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CN1419303A - Negative electrode material for nonelectrolyte cell and making method, negative electrode and cell - Google Patents

Negative electrode material for nonelectrolyte cell and making method, negative electrode and cell Download PDF

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CN1419303A
CN1419303A CN02147000A CN02147000A CN1419303A CN 1419303 A CN1419303 A CN 1419303A CN 02147000 A CN02147000 A CN 02147000A CN 02147000 A CN02147000 A CN 02147000A CN 1419303 A CN1419303 A CN 1419303A
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negative electrode
phase
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ltoreq
group
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泽孝雄
坂本敏也
河野龙兴
高见则雄
松野真辅
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Toshiba Corp
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Toshiba Corp
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Priority claimed from JP2001336931A external-priority patent/JP3844676B2/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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Abstract

The object of the present invention is to provide a negative electrode material for a nonaqueous electrolyte battery with a high discharge capacity, long charge-discharge cycle life, and excellent rate characteristics. The characteristics of the negative electrode material is that it has a composition represented by a general formula (1):(Al<1-x>Si<x>)<a>M<b>M'<c>T<d>......(1) and is essentially composed of an amorphous phase.

Description

Negative electrode material for nonaqueous electrolyte battery, method for producing same, negative electrode, and battery
Technical Field
The present invention relates to a negative electrode material for a nonaqueous electrolyte battery, a negative electrode comprising the negative electrode material, a nonaqueous electrolyte battery provided with the negative electrode, and a method for producing the negative electrode material for a nonaqueous electrolyte battery. The nonaqueous electrolyte battery of the present invention includes a nonaqueous electrolyte primary battery and a nonaqueous electrolyte secondary battery.
Background
In recent years, nonaqueous electrolyte batteries using metallic lithium as a negative electrode active material have attracted attention as high energy density batteries. Manganese dioxide (MnO) is used as the positive electrode active material2) Fluorinated carbon [ (CF)2)n]Thionyl chloride (SOCl)2) Etc. have been used for small electronic computers, power supplies for clocks, and backup batteries for memories. In recent years, with the miniaturization and weight reduction of various electronic devices such as VTRs and communication devices, lithium secondary batteries using lithium as a negative electrode active material have been actively studied as secondary batteries having a higher energy density required as power sources thereof.
As a lithium secondary battery, a battery having the following configuration has been studied. That is, the negative electrode containing metallic lithium is obtained by dissolving LiClO in a nonaqueous solvent such as Propylene Carbonate (PC), 1, 2-Dimethoxyethane (DME), γ -butyrolactone (γ -BL), Tetrahydrofuran (THF), or the like4、LiBF4、LiAsF6An electrolyte composed of a non-aqueous electrolyte or a lithium-conductive solid electrolyte of an equal lithium salt, and a compound (e.g., TiS) containing a compound which undergoes a partial chemical reaction with lithium as a positive electrode active material2、MoS2、V2O5、V6O13、MnO2Etc.) of the positive electrode.
However, the lithium secondary battery has not yet been put to practical use. The main reason for this is that the metal lithium used in the negative electrode is pulverized during repeated charge and discharge, and becomes reactive lithium dendrites, which deteriorate the safety of the battery and cause damage, short circuit, thermal explosion, and the like of the battery. Further, there is a problem that the charge-discharge efficiency is lowered due to the deterioration of lithium metal, and the cycle life is shortened.
Therefore, it has been proposed to use, instead of lithium metal, carbides capable of occluding and releasing lithium, such as coke, a resin sintered body, carbon fibers, and thermally decomposed gaseous carbon. In recent years, commercial lithium ion secondary batteries have been provided with a negative electrode containing a carbide and a negative electrode containing LiCoO2The positive electrode and the nonaqueous electrolyte of (1). In such a lithium ion secondary battery, when discharge occurs, lithium ions released from the negative electrode enter the nonaqueous electrolyte, and the lithium ions in the nonaqueous electrolyte are occluded by the negative electrode and react with each other during charge.
However, with the demand for further miniaturization and continuous use of electronic devices for a long time, further improvement in battery capacity is strongly desired. However, the improvement of the charge and discharge capacity of the conventional carbon material is limited, and the low-temperature sintered carbon having a high capacity has a low material density, and therefore, it is difficult to increase the charge and discharge capacity per unit volume. Therefore, in the course of research into high-capacity batteries, development of new negative electrode materials is required.
Japanese patent application laid-open No. 2000-311681 discloses a negative electrode material for a lithium secondary battery comprising particles containing an amorphous Sn.A.X alloy having a non-stoichiometric composition as a main component. In the formula, A represents at least one transition metal, and X represents at least one selected from O, F, N, Mg, Ba, Sr, Ca, La, Ce, Si, Ge, C, P, B, Bi, Sb, Al, In, S, Se, Te and Zn. Wherein X may not be included. The number of atoms in the above formula satisfies the relationship of Sn/(Sn + A + X) being 20 to 80 atom%.
As disclosed in Japanese patent laid-open No. 2000-311681, in an alloy system containing Sn as a basic element for Li-storing ability, if the Sn content is 20 atomic% or less, a high capacity cannot be obtained. In fact, Sn is used in Table 118Co82In the amorphous alloy shown, the initial charge-discharge efficiency, the discharge capacity and the cycle life were allNot as much as an amorphous alloy having a Sn content exceeding 80 atomic%. On the other hand, if the Sn content exceeds 80 atomic%, the capacity is increased, but the cycle life is shortened. Even with a composition having a relatively balanced capacity and cycle life, the battery cannot have a high capacity and a long life.
On the other hand, in paragraphs [0010] to [0012] of Japanese patent application laid-open No. 10-223221, in order to improve the discharge capacity and the charge-discharge cycle life of the secondary battery, it is disclosed to use a binary or ternary intermetallic compound containing a transition metal element such as Ni, Co, Fe and Al and a binary intermetallic compound of Al and Mg.
However, the nonaqueous electrolyte battery using the intermetallic compound described in JP-A-10-223221 is not satisfactory in not only discharge capacity and cycle life but also discharge rate characteristics.
In order to improve the discharge capacity, coulombic efficiency and rate characteristics, JP-A-10-302770 discloses x(0.5. ltoreq. X. ltoreq.3) in the above formula. Wherein A is one or more elements selected from Fe, Ni, Mn, Co, Mo, Cr, Nb, V, Cu and W, and B is one or more elements selected from Si, C, Ge, Sn, Pb, Al and P.
Paragraph [0025] of the above publication describes that the ratio Si to M (C, Ge, Sn, Pb, Al, P) of Si and M represented by B is in the range of 1: 0.2 (0.83: 0.17) to 1: 0.
However, ABxEven if the presence ratio of Si in B is 0.83 or more, the discharge capacity, cycle life and discharge ratio characteristics are not satisfactory.
Patent document 1: japanese patent laid-open No. 2000-311681 (claims scope, Table 1); patent document 2: japanese patent laid-open publication No. Hei 10-223221 (paragraphs [0010] - [0012 ]); patent document 3: japanese patent laid-open No. Hei 10-302770 (claim scope, paragraph [0025 ]).
The invention aims to provide a negative electrode material for a nonaqueous electrolyte battery, a method for producing the same, a negative electrode and a nonaqueous electrolyte battery, which are excellent in discharge capacity, charge-discharge cycle life and rate characteristics.
The invention aims to provide a negative electrode material for a nonaqueous electrolyte battery, a method for producing the same, a negative electrode and a nonaqueous electrolyte battery, which can realize a high discharge capacity and excellent rate characteristics.
Disclosure of Invention
The present invention 1 provides a negative electrode material for a nonaqueous electrolyte battery, having the following general formula (1): (A11-xSix)aMbM’cTd… … (1) substantially consisting of an amorphous phase, wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and M, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy the conditions that a + b + C + d is 100 at%, a is 50 at% or more and 95 at% or less, b is 5 at% or more and 40 at% or less, C is 0 at% or less and 10 at% or less, d is 0 at% or more and 20 at% or less, and x is 0 < 0.75.
The present invention 2 provides a negative electrode material for a nonaqueous electrolyte battery, which has the following general formula (2): (Al)1-xAx)aMbM’cTd… … (2) substantially consisting of an amorphous phase, wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a 50 at% or more and 95 at% or less, b 5 at% or more and 40 at% or less, C0 or more and 10 at% or less, d 0 or more and 20 at% or less, and x 0 < x or less and 0.9.
The invention 3 provides a non-aqueous solutionA negative electrode material for an electrolyte battery, which comprises a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a 50 at% or more and 95 at% or less, b 5 at% or more and 40 at% or less, C0 or less and 10 at% or less, d 0 or less and 20 at% or less, and x 0 and 0.75 at most.
The present invention 4 provides a negative electrode material for a nonaqueous electrolyte battery, which contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (4): (Al)1-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atom%, a is 50 atom% or more and 95 atom% or less, b is 5 atom% or more and 40 atom% or less, C is 0 atom% or more and 10 atom% or less, d is 0 atom% or more and 20 atom% or less, and x is 0 < x and 0.9.
The present invention 5 provides a negative electrode material for a nonaqueous electrolyte battery, having the following general formula (5): [ (Al)1-xSix)aMbM’cTd]yLiz… … (5) substantially consisting of an amorphous phase, wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z each satisfy the conditions that a + b + C + d is 1, a is 0.5. ltoreq. a.ltoreq.0.95, and b is 0.05. ltoreq. b.ltoreq.0And 4, c is more than or equal to 0 and less than or equal to 0.1, d is more than or equal to 0 and less than 0.2, x is more than 0 and less than 0.75, y and z are 100 atomic percent, and z is more than 0 and less than or equal to 50 atomic percent.
The present invention 6 provides a negative electrode material for a nonaqueous electrolyte battery, which has the following general formula (6): [ (Al)1-xAx)aMbM’cTd]yLiz… … (6) substantially consisting of an amorphous phase, wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z satisfy a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq. b.ltoreq.0.4, c.ltoreq.0.1, d.ltoreq.0.2, x.ltoreq.0.9, y + z is 100 at%, and z is 0 < z.ltoreq.50 at%.
The present invention 7 provides a negative electrode material for a nonaqueous electrolyte battery, which contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (7): [ (Al)1-xSix)aMbM’cTd]yLiz… … (7), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each a + b + C + d equal to 1, 0.5. ltoreq. a equal to or less than 0.95, 0.05. ltoreq. b equal to or less than 0.4, 0. ltoreq. C equal to or less than 0.1, 0. ltoreq. d equal to or less than 0.2, 0. ltoreq. x < 0.75, y + z equal to 100 atomic%, 0. ltoreq. z equal to or less than 50 atomic%.
The present invention 8 provides a negative electrode material for a nonaqueous electrolyte battery, which contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, and M is at least one element selected from the group consisting of Fe, Co, Ni and MnM' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq. b.ltoreq.0.4, C is 0. ltoreq. c.ltoreq.0.1, d is 0. ltoreq. d.ltoreq.0.2, x is 0. ltoreq. x.0.9, y + z is 100 atomic%, and z is 0. ltoreq. 50 atomic%.
The present invention 9 provides a negative electrode material for a nonaqueous electrolyte battery, which can store and release lithium, and which exhibits at least one exothermic peak in a range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, and in X-ray diffraction, a diffraction peak based on a crystalline phase.
The present invention 10 provides a negative electrode material for a nonaqueous electrolyte battery, which comprises a first phase containing intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm and containing two or more elements alloyable with lithium, and a second phase mainly composed of an element alloyable with lithium and having a particle diameter of 1 μm2The number of the intermetallic compound crystal particles is 10 to 2000, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
The present invention 11 provides a negative electrode material for a nonaqueous electrolyte battery, comprising a first phase and a second phase, wherein the first phase contains intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase is mainly composed of an element capable of alloying with lithium, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, the average distance between the intermetallic compound crystal particles is 500nm or less, and the second phase is precipitated in a state of being buried between the isolated crystal particles.
The present invention 12 provides a negative electrode material for a nonaqueous electrolyte battery, which comprises a first phase containing intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, and a second phase mainly containing an element capable of alloying with lithium, wherein the intermetallic compound crystal particles have a cubic fluorite structure having a lattice constant of 5.42 to 6.3 a or an inverted fluorite structure having a lattice constant of 5.42 to 6.3 a, at least a part of the intermetallic compound crystal particles are isolated from each other, and the second phase is deposited in a state of being buried between the isolated crystal particles.
The present invention 13 provides a negative electrode material for a nonaqueous electrolyte battery, which comprises an intermetallic compound phase containing two or more elements capable of alloying with lithium and a second phase mainly composed of an element capable of alloying with lithium, and in a powder X-ray diffraction measurement, a diffraction peak from the intermetallic compound phase appears when a d value is at least 3.13 to 3.64. ang. and 1.92 to 2.23. ang. and a diffraction peak from the second phase appears when a d value is at least 2.31 to 2.40. ang.
The present invention 14 provides a negative electrode material for a nonaqueous electrolyte battery, which comprises a monomer phase of an element that alloys with lithium and a plurality of intermetallic compound phases, wherein at least two of the plurality of intermetallic compound phases respectively contain an element that alloys with lithium and an element that does not alloy with lithium, and wherein combinations of the element that alloys with lithium and the element that does not alloy with lithium are different from each other.
The present invention 15 provides a negative electrode material for a nonaqueous electrolyte battery, which has a monomer phase, an intermetallic compound phase, and a nonequilibrium phase of an element that is alloyed with lithium.
The present invention 16 provides a negative electrode comprising a negative electrode having the following general formula (1): (Al)1-xSix)aMbM’cTd… … (1), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and M, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and the alloy is substantially composed of an amorphous phasea. b, c, d and x respectively satisfy the conditions that a + b + c + d is 100 atom percent, a is more than or equal to 50 atom percent and less than or equal to 95 atom percent, b is more than or equal to 5 atom percent and less than or equal to 40 atom percent, c is more than or equal to 0 and less than or equal to 10 atom percent, d is more than or equal to 0 and less than 20 atom percent, and x is more than 0 and less than 0.75.
The present invention 17 provides an anode comprising a metal having the following general formula (2): (Al)1-xAx)aMbM’cTd… … (2), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a is 50 at% or more and 95 at% or less, b is 5 at% or more and 40 at% or less, C is 0 or more and 10 at% or less, d is 0 or more and 20 at% or less, and x is 0 or more and 0.9 or less, respectively.
The present invention 18 provides a negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, 50 at% or more and a less than 95 at%, 5 at% or more and b less than 40 at%, 0 or more and C less than 10 at%, 0 or more and d less than 20 at%, and 0 < x < 0.75, respectively.
The present invention 19 provides a negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (4): (Al)1-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, and M' is at least one element selected from the group consisting of Cu, Ti, and Mn,Zr, Hf, V, Nb, Ta, Cr, Mo, W and at least one element of rare earth elements, the T is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d and x respectively satisfy the condition that a + b + C + d is 100 atom%, a is not less than 50 atom% and not more than 95 atom%, b is not less than 5 atom% and not more than 40 atom%, C is not less than 0 and not more than 10 atom%, d is not less than 0 and not more than 20 atom%, x is not less than 0 and not more than 0.9.
The present invention 20 provides an anode comprising a metal having the following general formula (5): [ (Al)1-xSix)aMbM’cTd]yLiz… … (5), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z each satisfy a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z.50 atomic%.
The present invention 21 provides an anode comprising a metal having the following general formula (6): [ (Al)1-xAx)aMbM’cTd]yLiz… … (6) wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each a + b + C + d ═ 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.ltoreq.0.9, y + z ═ 100 atomic%, 0. ltoreq. z.ltoreq. 50 atomic%.
The present invention 22 provides a negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (7): [ (Al)1-xSix)aMbM’cTd]yLiz… … (7), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z are each a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z 50 atomic%.
The present invention 23 provides a negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, M is at least one element selected from Fe, Co, Ni and Mn, M' is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d, x, y and z satisfy a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq.0.4, C is 0. ltoreq.0.1, d is 0. ltoreq. 0.2, x is 0. ltoreq.0.9, y + z is 100 atomic%, and z is 0. ltoreq. z.50 atomic%.
The present invention 24 provides a negative electrode comprising a negative electrode material capable of occluding and releasing lithium, wherein the negative electrode material exhibits at least one exothermic peak in a range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, and exhibits a diffraction peak based on a crystal phase in X-ray diffraction.
The present invention 25 provides a negative electrode comprising a negative electrode material having a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm and containing two or more elements alloyable with lithium, and the second phase mainly contains an element alloyable with lithium and has a particle diameter of 1 μm2The number of the intermetallic compound crystal particles is 10 to 2000, and the number of the intermetallic compound crystal particles is up toAt least a part of the phases are isolated from each other and precipitated, and the second phase is buried between the isolated crystal grains.
The present invention 26 provides a negative electrode comprising a negative electrode material including a first phase and a second phase, wherein the first phase includes intermetallic compound crystal particles containing two or more elements that can be alloyed with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element that can be alloyed with lithium, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, an average distance between the intermetallic compound crystal particles is 500nm or less, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
The present invention 27 provides a negative electrode comprising a negative electrode material having a first phase and a second phase, wherein the first phase contains intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, the intermetallic compound crystal particles have a cubic fluorite structure having a lattice constant of 5.42 to 6.3 a or an inverted fluorite structure having a lattice constant of 5.42 to 6.3 a, at least a part of the intermetallic compound crystal particles are isolated from each other, and the second phase is isolated in a state of being buried between the isolated crystal particles.
The present invention 28 provides a negative electrode comprising a negative electrode material having an intermetallic compound phase containing two or more elements alloyable with lithium and a second phase mainly composed of an element alloyable with lithium, wherein in a powder X-ray diffraction measurement, a diffraction peak from the intermetallic compound phase appears at d values of at least 3.13 to 3.64 and 1.92 to 2.23, and a diffraction peak from the second phase appears at d values of at least 2.31 to 2.40.
The present invention 29 provides a negative electrode including a negative electrode material having a single phase of an element that alloys with lithium and a plurality of intermetallic compound phases, at least two of the plurality of intermetallic compound phases respectively including an element that alloys with lithium and an element that does not alloy with lithium, combinations of the element that alloys with lithium and the element that does not alloy with lithium being different from each other.
The present invention 30 provides a negative electrode comprising a negative electrode material having a monomer phase, an intermetallic compound phase, and a non-equilibrium phase of an element that alloys with lithium.
The present invention 31 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, the negative electrode comprising a negative electrode having the following general formula (1): (Al)1-xSix)aMbM’cTd… … (1), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and M, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atomic%, a is 50 atomic% or more and 95 atomic% or less, b is 5 atomic% or more and 40 atomic% or less, C is 0 atomic% or more and 10 atomic% or less, d is 0 atomic% or more and 20 atomic% or less, and x is 0 < 0.75.
The present invention 32 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode comprises a negative electrode having the following general formula (2): (Al)1-xAx)aMbM’cTd… … (2), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a is 50 at% or more and 95 at% or less, b is 5 at% or more and 40 at% or less, C is 0 or more and 10 at% or less, d is 0 or more and 20 at% or less, and x is 0 or more and 0.9 or less, respectively.
The invention 33 provides a nonaqueous electrolyte battery having a negative electrode, a positive electrode and a nonaqueous electrolyteThe negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less, and has the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, 50 at% or more and a less than 95 at%, 5 at% or more and b less than 40 at%, 0 or more and C less than 10 at%, 0 or more and d less than 20 at%, and 0 < x < 0.75, respectively.
The present invention 34 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (4): (A11-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atom%, a is 50 atom% or more and 95 atom% or less, b is 5 atom% or more and 40 atom% or less, C is 0 atom% or more and 10 atom% or less, d is 0 atom% or more and 20 atom% or less, and x is 0 < x and 0.9.
The present invention 35 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, the negative electrode comprising a negative electrode having the following general formula (5): [ (Al)1-xSix)aMbM’cTd]yLiz… … (5), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, and T is at least one element selected from the group consisting of C, Ge, Pb, P and SnAn element wherein a, b, c, d, x, y and z are each 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq. b.ltoreq.0.4, c is 0. ltoreq. c.ltoreq.0.1, d is 0. ltoreq. d.ltoreq.0.2, x is 0. ltoreq. x.ltoreq.0.75, y + z is 100 atomic%, and z is 0. ltoreq. z.ltoreq.50 atomic%.
The present invention 36 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, the negative electrode comprising a negative electrode having the following general formula (6): [ (Al)1-xAx)aMbM’cTd]yLiz… … (6) wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each a + b + C + d ═ 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.ltoreq.0.9, y + z ═ 100 atomic%, 0. ltoreq. z.ltoreq. 50 atomic%.
The present invention 37 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (7): [ (Al)1-xSix)aMbM’cTd]yLiz… … (7), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z are each a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z 50 atomic%.
The invention 38 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal grain size of 500nm or less, andhaving the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, M is at least one element selected from Fe, Co, Ni and Mn, M' is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d, x, y and z satisfy a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq.0.4, C is 0. ltoreq.0.1, d is 0. ltoreq. 0.2, x is 0. ltoreq.0.9, y + z is 100 atomic%, and z is 0. ltoreq. z.50 atomic%.
The present invention 39 provides a nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode comprises a negative electrode material capable of occluding and releasing lithium, and the negative electrode material exhibits at least one exothermic peak in a range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, and exhibits a diffraction peak based on a crystal phase in X-ray diffraction.
The present invention 40 provides a nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode, and a nonaqueous electrolyte, wherein the negative electrode material comprises a first phase and a second phase, the first phase comprises intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm and containing two or more elements alloyable with lithium, and the second phase mainly contains an element alloyable with lithium and has a particle diameter of 1 μm2The number of the intermetallic compound crystal particles is 10 to 2000, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
The present invention 41 provides a nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode, and a nonaqueous electrolyte, wherein the negative electrode material comprises a first phase and a second phase, the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, the average distance between the intermetallic compound crystal particles is 500nm or less, and the second phase is precipitated in a state of being buried between the isolated crystal particles.
The present invention 42 provides a nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode, and a nonaqueous electrolyte, wherein the negative electrode material comprises a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal grain diameter of 5 to 500nm, the second phase is mainly composed of an element capable of alloying with lithium, the intermetallic compound crystal particles have a cubic fluorite structure having a lattice constant of 5.42 to 6.3 a or an inverse fluorite structure having a lattice constant of 5.42 to 6.3 a, at least a part of the intermetallic compound crystal particles are isolated from each other and precipitated in a state where the second phase is embedded between the isolated crystal particles.
The present invention 43 provides a nonaqueous electrolyte battery comprising a negative electrode material, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode material comprises an intermetallic compound phase comprising two or more elements capable of alloying with lithium and a second phase mainly composed of an element capable of alloying with lithium, and wherein in a powder X-ray diffraction measurement, a diffraction peak derived from the intermetallic compound phase appears at d values of at least 3.13 to 3.64_ and 1.92 to 2.23_ and a diffraction peak derived from the second phase appears at d values of at least 2.31 to 2.40 _.
The present invention 44 provides a nonaqueous electrolyte battery comprising a negative electrode including a negative electrode material, a positive electrode, and a nonaqueous electrolyte, wherein the negative electrode material includes a single phase of an element that is alloyed with lithium and a plurality of intermetallic compound phases, at least two of the plurality of intermetallic compound phases include an element that is alloyed with lithium and an element that is not alloyed with lithium, respectively, and combinations of the element that is alloyed with lithium and the element that is not alloyed with lithium are different from each other.
The present invention 45 provides a nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material having a monomer phase of an element that is alloyed with lithium, an intermetallic compound phase, and a nonequilibrium phase, a positive electrode, and a nonaqueous electrolyte.
The present invention 46 provides a method for producing a negative electrode material for a nonaqueous electrolyte battery, comprising injecting a metal solution containing first to third elements onto a single roll, rapidly cooling the metal solution to a thickness of 10 to 500 μm, and solidifying a metal structure containing an intermetallic compound phase having a high melting point and a second phase, wherein the intermetallic compound phase contains the first to third elements, the second phase is mainly composed of the first element and has a melting point lower than that of the intermetallic compound phase, the first element is at least one element selected from the group consisting of Al, In, Pb, Ga, Sb, Bi, Sn, and Zn, the second element is at least one element selected from the group consisting of elements other than Al, In, Pb, Ga, Sb, Bi, Sn, and Zn which can be alloyed with lithium, and the third element is an element capable of forming an intermetallic compound with the first element and the second element.
The present invention 47 provides a method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by injecting a metal solution containing Al, an element N1, an element N2, and an element N3 into a single roll, rapidly cooling the metal solution to a thickness of 10 to 500 μm, and solidifying a metal structure containing an intermetallic compound phase having a high melting point and a second phase, wherein the intermetallic compound phase contains Al, an element N1, and an element N2, the second phase is mainly Al and has a lower melting point than the intermetallic compound phase, the element N1 is Si or Si and Mg, the element N2 is at least one element selected from Ni and Co, the element N3 is at least one element selected from In, Bi, Pb, Sn, Ga, Sb, Zn, Fe, Cu, Mn, Cr, Ti, Zr, Nb, Ta, and the metal solution contains h atom%, and the element N1 In the metal solution is i atom%, When the content of N2 in the metal solution is j atom%, and the content of N3 in the metal solution is k atom%, h, i, j and k respectively satisfy 12.5-h < 95, 0-i < 71, 5-j < 40, and 0-k < 20, the invention provides a non-aqueous electrolyteA method for producing a negative electrode material for a cell, which is characterized by comprising subjecting a material having the following general formula (9): x xTlyJz… … (9) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein X is at least two elements selected from Al, Si, Mg, Sn, Ge, In, Pb, P and C, Tl is at least one element selected from Fe, Co, Ni, Cr and Mn, J is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, X, y and z respectively satisfy X + y + z as 100 atom%, X is not less than 50 and not more than 90, y is not less than 10 and not more than 33, and z is not less than 0 and not more than 10.
The present invention 49 provides a method for producing a negative electrode material for a nonaqueous electrolyte battery, the method being characterized by comprising forming a negative electrode material having the following general formula (10) by a single roll method: al (Al)aTlbJcZd… … (10) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein Al is at least one element selected from the group consisting of Si, Mg and Al, Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C and d satisfy a + b + C + d as 100 atomic%, a is 50. ltoreq. a.ltoreq.95, b is 5. ltoreq. b.ltoreq.40, C is 0. ltoreq. c.ltoreq.10, and d is 0. ltoreq. d.ltoreq.20, respectively.
The present invention 50 provides a method for producing a negative electrode material for a nonaqueous electrolyte battery, the method being characterized by comprising forming a negative electrode material having the following general formula (11): tl100-a-b-c(A21-xJ’x)aBbJc… … (11) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein,tl is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, A2 is at least one element selected from the group consisting of Al and Si, J is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, J' is at least one element selected from the group consisting of C, Ge, Pb, P, Sn and Mg, a, b, C and x satisfy, respectively, 10 atom% or less of a and 85 atom%, 0 < b and 35 atom%, 0 or less of C and 10 atom%, 0 or less of x and 0.3, and the content of Sn is less than 20 atom% (including 0 atom%).
The present invention 51 provides a method for producing a negative electrode material for a nonaqueous electrolyte battery, the method being characterized by comprising forming a negative electrode material having the following general formula (12) by a single roll method: (Mg)1-xA3x)100-a-b-c-d(RE)aTlbMlcA4d… … (12) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein A3 is at least one element selected from the group consisting of Al, Si and Ge, RE is at least one element selected from the group consisting of Y and rare earth elements, Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, M1 is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, A4 is at least one element selected from the group consisting of Sn, Pb, Zn, P and C, a, b, C, d and x are each 0 < a < 40 at%, 0 < b < 40 at%, 0 < C < 10 at%, 0 < d < 20 at%, and 0 < x < 0.5.
The present invention 52 provides a method for producing a negative electrode material for a nonaqueous electrolyte battery, the method being characterized by comprising forming a negative electrode material having the following general formula (13) by a single roll method: (Al)1-xA5x)aTlbJcZd… … (13) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein A5 is at least one element selected from Si and Mg, T1 is at least one element selected from Fe, Co, Ni, Cr and Mn, and J is at least one element selected fromAt least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, wherein Z is at least one element selected from C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atomic%, a is not less than 50 and not more than 95, b is not less than 5 and not more than 40, C is not less than 0 and not more than 10, d is not less than 0 and not more than 20, and x is not less than 0 and not more than 0.9, respectively.
Drawings
Fig. 1 is a sectional view of a thin nonaqueous electrolyte secondary battery as an example of the nonaqueous electrolyte battery of the present invention.
Fig. 2 is an enlarged sectional view of a portion a of fig. 1.
Fig. 3 is an X-ray diffraction pattern of the anode material of example 1.
Fig. 4 is an X-ray diffraction pattern of the anode material of example 15.
Fig. 5 is a schematic view of the metal structure of the negative electrode material for a nonaqueous electrolyte battery of the present invention.
Fig. 6 is an X-ray diffraction pattern of the anode material of example 52.
Fig. 7 is a transmission electron micrograph (magnification: 10 ten thousand times) of the anode material of example 52.
Fig. 8 is a DSC graph showing differential scanning calorimetry of the anode material of example 52.
FIG. 9 is an X-ray diffraction pattern of the anode material of example 73.
Fig. 10 is an X-ray diffraction pattern of the negative electrode material of example 89.
Description of the symbols:
the number 1 is an outer package member, and,
2 is an electrode group, and the electrode group,
3 is an interlayer which is used as a coating,
4 is a positive electrode layer, and the anode layer,
5 is a positive electrode current collector, and,
the positive electrode is 6, and the negative electrode is,
7 is a negative electrode layer, and the negative electrode layer,
8 is a negative electrode current collector,
9 is a negative electrode, and the negative electrode,
a positive electrode terminal 10 is provided as a positive electrode terminal,
and 11 is a negative electrode terminal.
Detailed Description
First, the negative electrode material for nonaqueous electrolyte batteries according to the present invention 1 to 12 will be described.
< negative electrode Material for nonaqueous electrolyte Battery 1>
The negative electrode material for a nonaqueous electrolyte battery of the present invention 1 comprises a negative electrode material having the following general formula (1): (Al)1-xSix)aMbM’cTd… … (1), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and M, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atomic%, a is 50 atomic% or more and 95 atomic% or less, b is 5 atomic% or more and 40 atomic% or less, C is 0 atomic% or more and 10 atomic% or less, d is 0 atomic% or more and 20 atomic% or less, and x is 0 < 0.75.
As the metal structure substantially composed of an amorphous phase, a structure in which a peak due to a crystalline phase does not appear in X-ray diffraction can be exemplified.
(aluminum and Si)
Al and Si are basic elements for occluding lithium. When the atomic ratio x of Si is 0.75 or more, a metal structure substantially consisting of an amorphous phase is not obtained, and the cycle life of the secondary battery is reduced. The atomic ratio x is more preferably in the range of 0.3 to 0.75.
The total atomic ratio of Al and Si is in the range of 50 to 95 atomic%. When the total atomic ratio is less than 50 atomic%, the lithium storage energy of the negative electrode material decreases, and it is difficult to further improve the discharge capacity, cycle life, and rate characteristics of the secondary battery. On the other hand, when the total atomic ratio exceeds 95 atomic%, the lithium release reaction hardly occurs in the negative electrode material. The total atomic ratio is more than 67 atomic% and less than 90 atomic%, preferably 70 atomic% to 88 atomic%.
(element M)
Three elements of Al and Si and the element M promote amorphization. The element M can suppress micronization in the case of storing and releasing lithium in the negative electrode material. When the atomic ratio b of the element M is less than 5 atomic%, amorphization becomes difficult. On the other hand, when the atomic ratio b of the element M is more than 40 atomic%, the discharge capacity of the secondary battery is significantly reduced. The atomic ratio b of the element M is more preferably in the range of 7 to 35 atomic%.
(element M')
Examples of the rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. Among them, La, Ce, Pr, Nd, Sm are preferred.
The element M' is contained at an atomic ratio of 10 at% or less, whereby amorphization can be promoted. In addition, the retention of occluded Li in the alloy can be reduced, and the decrease in charge and discharge capacity can be suppressed. The atomic ratio c is more preferably 8 atomic% or less. Among them, when the amount of the atomic ratio c is less than 0.01 atomic%, the effects of promoting amorphization and suppressing the decrease in charge-discharge capacity may not be obtained, and therefore the lower limit of the atomic ratio c is preferably 0.01 atomic%.
(element T)
The element T may promote amorphization. When the element T is contained in an atomic ratio d of 20 atomic% or less, the capacity can be increased or the service life can be prolonged. However, when the atomic ratio d is 20 atomic% or more, the cycle life is reduced. A more preferable range of the atomic ratio d is 15 atomic% or less.
In the nonaqueous electrolyte secondary battery having the negative electrode material of the present invention 1, the alloy composition contained in the negative electrode material does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may change the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (5).
< negative electrode Material for nonaqueous electrolyte Battery 2>
The negative electrode material 2 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (2): (Al)1-xAx)aMbM’cTd… … (2), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a is 50 at% or more and 95 at% or less, b is 5 at% or more and 40 at% or less, C is 0 or more and 10 at% or less, d is 0 or more and 20 at% or less, and x is 0 or more and 0.9 or less, respectively.
As the metal structure substantially composed of an amorphous phase, a structure in which a peak due to a crystalline phase does not appear in X-ray diffraction can be exemplified.
(aluminum and element A)
Al and the element A (Mg or Mg and Si) are basic elements for occluding lithium. When the atomic ratio x of the element a is 0.9 or more, a metal structure composed of an amorphous phase is not substantially obtained, and the cycle life and the rate characteristics of the secondary battery are also degraded. A more preferable range of the atomic ratio x is 0.3. ltoreq. x.ltoreq.0.8.
The total atomic ratio of Al and the element A is in the range of 50 to 95 atomic%. When the total atomic ratio is less than 50 atomic%, the lithium storage energy of the negative electrode material decreases, and the discharge capacity, cycle life, and rate characteristics of the secondary battery are difficult to improve. On the other hand, when the total atomic ratio exceeds 95 atomic%, the lithium release reaction hardly occurs in the negative electrode material. The total atomic ratio is more preferably 70 to 90 atomic%.
(element M)
Three elements of Al, element a, and element M may promote amorphization. The element M can suppress micronization in the case of storing and releasing lithium in the negative electrode material. When the atomic ratio b of the element M is less than 5 atomic%, amorphization becomes difficult. On the other hand, when the atomic ratio b of the element M is more than 40 atomic%, the discharge capacity of the secondary battery is significantly reduced. The atomic ratio b of the element M is more preferably in the range of 7 to 35 atomic%.
(element M')
The rare earth elements are the same as those exemplified for the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
By containing the element M' in an atomic ratio of 10 at% or less, amorphization can be promoted. In addition, the retention of the occluded Li in the alloy can be reduced, and the decrease in charge/discharge capacity can be suppressed. The atomic ratio c is more preferably 8 atomic% or less. However, when the amount of the atomic ratio c is less than 0.01 atomic%, the effects of promoting amorphization and suppressing the decrease in charge-discharge capacity may not be obtained, and therefore the lower limit of the atomic ratio c is preferably 0.01 atomic%.
(element T)
The element T may promote amorphization. By including the element T in the range of 20 atomic% or less in the atomic ratio d, the capacity can be improved or the service life can be prolonged. However, when the atomic ratio d is 20 atomic% or more, the cycle life is reduced. A more preferable range of the atomic ratio d is 15 atomic% or less.
In the nonaqueous electrolyte secondary battery having the negative electrode material of the present invention 2, the alloy composition contained in the negative electrode material does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may change the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (6).
The anode materials 1 and 2 may be prepared by a liquid quenching method, a mechanical alloying method, or a mechanical milling method.
(liquid quenching method)
The liquid quenching method is a method of ejecting an alloy metal solution prepared to have a predetermined composition from a small nozzle onto a cooling member (e.g., a roll) rotating at a high speed to quench the alloy metal solution. The shape of the sample obtained by the liquid quenching method includes a long thin strip shape, a flake shape, and the like. When the composition of the sample is changed, the melting point thereof is changed, and thus the shape of the sample is also changed according to the change in the composition. When the metallic structure is substantially constituted by an amorphous phase, a long thin strip is easily obtained. On the other hand, the cooling rate mainly dominates the thickness of the quenched sample, and the sample thickness is adjusted depending on the material of the roll, the number of revolutions of the roll, and the nozzle hole diameter.
The optimum material is determined by the wettability of the roll material and the alloy metal solution, and an alloy containing Cu as a main component (e.g., Cu, TiCu, ZrCu, BeCu) is preferable.
The rotational speed of the roller is determined by the material composition, but the amorphization is easily realized within the range of 20 to 60 m/s. When the roller rotation speed is less than 20m/s, a mixed phase of a microcrystalline phase and an amorphous phase is easily obtained. On the other hand, when the roll rotation speed is more than 60m/s, the alloy metal solution is hard to be held on the cooling roll rotating at a high speed, and therefore, the cooling speed is lowered, and the fine crystal phase is liable to be precipitated. Generally, the target crystallites are obtained at a roll rotation speed of about 10m/s or more depending on the composition.
The nozzle diameter is preferably in the range of 0.3 to 2 mm. When the nozzle diameter is less than 0.3mm, it is difficult to eject the metal solution from the nozzle. On the other hand, if the nozzle diameter exceeds 2mm, a thick sample can be easily obtained, but it is difficult to obtain a sufficient cooling rate.
The gap between the roller and the nozzle is preferably in the range of 0.2 to 10mm, and when the gap exceeds 10mm, if the flow of the metal solution is laminar, the cooling rate can be uniformly increased. However, when the gap is widened, a thicker sample is obtained, and therefore the cooling rate is slower as the gap is wider.
It is desirable to increase the heat capacity of the roll because of the large amount of heat that needs to be extracted from the alloy metal solution in mass production. The roll diameter is preferably over 300mm phi, more preferably over 500mm phi. The width of the roller is preferably 50mm or more, more preferably 100mm or more.
(mechanical alloying method and mechanical grinding method)
The mechanical alloying method and the mechanical milling method are methods in which powders prepared to have a predetermined composition are charged into a crucible in an inert atmosphere, and the powders are sandwiched by rolling balls in the crucible by rotation, whereby an alloy is obtained by the energy at that time
An alloy substantially composed of amorphous, which is obtained by a liquid quenching method, a mechanical alloying method, or a mechanical milling method, can be embrittled by performing a heat treatment. From the viewpoint of avoiding microcrystallization, the heat treatment temperature is preferably not higher than the crystallization temperature.
In addition to the liquid quenching method, the mechanical alloying method, and the mechanical milling method, a gas atomization method, a rotary disk method, a rotary electrode method, and the like can be used to obtain a powdery sample. These methods can obtain a spherical sample by selecting conditions, and therefore, the negative electrode material can be most densely packed in the negative electrode, thereby realizing a high capacity battery.
< negative electrode Material for nonaqueous electrolyte Battery 3>
The negative electrode material 3 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a 50 at% or more and 95 at% or less, b 5 at% or more and 40 at% or less, C0 or more and 10 at% or less, d 0 or more and 20 at% or less, and x 0 < 0.75.
The negative electrode material 3 may be substantially composed of the above-described microcrystalline phase, or may be composed of a composite phase of the above-described microcrystalline phase and an amorphous phase.
The microcrystalline phase may be composed of an intermetallic compound, a compound having a non-stoichiometric composition, or an alloy having a non-stoichiometric composition, and is preferably composed of a plurality of compound or alloy phases from the viewpoint of the service life and capacity.
When the average crystal grain size of the microcrystalline phase is more than 500nm, since micronization of the negative electrode material is performed quickly, electrical contact between the negative electrode materials or between the conductive additive and the negative electrode material is reduced during electrode fabrication, discharge capacity is reduced, and charge-discharge life cycle life is reduced. The average crystal grain size is more preferably in the range of 5nm to 500nm, still more preferably in the range of 5nm to 300 nm.
The average crystal grain size can be determined from the half width of the X-ray diffraction line according to the Scherrer formula. A Transmission Electron Microscope (TEM) photograph may be taken, and the average of the maximum particle diameters of 20 particles arbitrarily selected therefrom is taken as the average crystal particle diameter. In a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), 50 crystal grains adjacent to each other are selected, the longest portion of each crystal grain is defined as a grain diameter, the length thereof is measured, and the average value thereof is defined as an average crystal grain diameter. The magnification of the TEM photograph can be changed depending on the measured particle size.
The ratio of the microcrystalline phase in the composite phase of the microcrystalline phase and the amorphous phase is measured by (a) Differential Scanning Calorimetry (DSC) or (b) X-ray diffraction measurement.
(a) Differential Scanning Calorimetry (DSC)
When an alloy composed of an amorphous phase is measured by Differential Scanning Calorimetry (DSC), the heat is released at the crystallization temperature, and thus the amount of heat released is used as a reference amount of heat. The ratio of the microcrystalline phases was evaluated by comparing the heat release with a reference heat release by performing Differential Scanning Calorimetry (DSC) on an alloy with an unknown ratio of the microcrystalline phases.
(b) Diffraction by X-ray
The ratio of the microcrystalline phases was evaluated by comparing the intensity of the same diffraction peak of an alloy with an unknown ratio of the microcrystalline phases with a reference intensity, based on the diffraction intensity of the strongest peak in the X-ray diffraction pattern of the alloy with the known ratio of the microcrystalline phases.
(aluminum and Si)
Al and Si are basic elements for occluding lithium. When the atomic ratio x of Si is 0.75 or more, the cycle life of the secondary battery is reduced. The atomic ratio x is more preferably in the range of 0.3 to 0.75.
The total atomic ratio of Al and Si is in the range of 50 to 95 atomic%. When the total atomic ratio is less than 50 atomic%, the lithium storage energy of the negative electrode material decreases, and the discharge capacity, cycle life, and rate characteristics of the secondary battery are difficult to improve. On the other hand, when the total atomic ratio exceeds 95 atomic%, the negative electrode material hardly causes a lithium release reaction. The total atomic ratio is more than 67 atomic% and less than 90 atomic%, preferably 70 atomic% or more and 88 atomic% or less.
(element M)
Three elements, Al, Si and M, promote the grain refinement. The element M suppresses micronization of the negative electrode material during the occlusion and release of lithium. When the atomic ratio b of the element M is less than 5 atomic%, it is difficult to refine the crystal grains. On the other hand, when the atomic ratio b of the element M is more than 40 atomic%, the discharge capacity of the secondary battery is significantly reduced. The atomic ratio b of the element M is more preferably in the range of 7 to 35 atomic%.
(element M')
Specific examples of the rare earth elements are the same as those of the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
By containing the element M' in an atomic ratio of 10 atomic% or less, the grain refinement can be promoted. The retention of the occluded Li in the alloy is reduced, and the decrease of the charge/discharge capacity is suppressed. The atomic ratio c is more preferably 8 atomic% or less. However, when the amount of the atomic ratio c is less than 0.01 atomic%, there is a possibility that the effect of promoting the refinement of crystal grains and suppressing the decrease in charge-discharge capacity cannot be obtained, and therefore the lower limit of the atomic ratio c is preferably 0.01 atomic%.
(element T)
The element T promotes the refinement of crystal grains. When the element T is contained in an atomic ratio d of 20 atomic% or less, the capacity can be increased or the service life can be prolonged. However, when the atomic ratio d is 20 atomic% or more, the cycle life is reduced. A more preferable range of the atomic ratio d is 15 atomic% or less.
In the nonaqueous electrolyte secondary battery having the negative electrode material of the present invention 3, the alloy composition contained in the negative electrode material does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may change the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (7).
The negative electrode material 3 can be produced by the following methods (1) to (3).
(1) The alloy substantially composed of an amorphous phase obtained by the liquid quenching method, the mechanical alloying method, or the mechanical milling method is heated at a temperature higher than the crystallization temperature thereof, and a microcrystalline phase is precipitated by heat treatment, thereby obtaining the negative electrode material 3.
The crystallization temperature is a temperature obtained from the first exothermic peak when the material is subjected to thermal analysis. Specifically, the temperature of the intersection point of the extension line of the line having no change and the steepest rise in the gradient of the exothermic peak was measured at a temperature rise rate of 10 ℃/min using a differential scanning calorimeter. When the negative electrode material contains a trace amount of the element M', the average crystal grain size can be easily controlled to 500nm or less. The 4d, 4f, 5d transition metals in which Zr, Hf, Nb, Ta, Mo, W, rare earth elements are added in small amounts to the element M' can achieve a high accelerating effect in terms of grain refinement. When the addition amounts of Ti, V and Cr in the element M' are increased, a high effect of refining crystal grains can be obtained.
(2) The liquid quenching method can directly separate out the microcrystals. In this case, by adjusting the cooling rate of the metal solution, crystals having an appropriate particle diameter can be precipitated in an optimum ratio. The thickness of the quenched material depends on the cooling rate, and the thickness is controlled by adjusting the rotational speed of the cooling roll, the material of the roll, the amount of the metal solution supplied (nozzle hole diameter), and the like. The alloy obtained by the liquid quenching method is subjected to heat treatment to embrittle the alloy or control the microstructure (adjustment of the size of the grain size and the precipitation ratio of the microcrystalline phase).
(3) The negative electrode material 3 can be obtained by a mechanical alloying method or a mechanical grinding method.
< negative electrode Material for nonaqueous electrolyte Battery 4>
The negative electrode material 4 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (4): (Al)1-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy the conditions that a + b + C + d is 100 atomic%, a is 50 atomic% or more and 95 atomic% or less, b is 5 atomic% or more and 40 atomic% or less, C is 0 atomic% or less and 10 atomic% or less, d is 0 atomic% or less and 20 atomic% or less, and x is 0 < x and 0.9.
The negative electrode material 4 may be substantially composed of the above-described microcrystalline phase, or may be composed of a composite phase of the above-described microcrystalline phase and an amorphous phase.
The microcrystalline phase may be composed of an intermetallic compound, a compound having a nonstoichiometric composition, or an alloy having a nonstoichiometric composition, and is preferably composed of a plurality of compound or alloy phases from the viewpoint of service life and capacity.
The reason why the average crystal grain size of the microcrystalline phase is 500nm or less is the same as that described for the negative electrode material 3. The average crystal grain size is more preferably in the range of 5nm to 500nm, still more preferably in the range of 5nm to 300 nm.
The average crystal grain size can be determined from the half width of the X-ray diffraction line according to the Scherrer formula. A Transmission Electron Microscope (TEM) photograph may be taken, and the average of the maximum particle diameters of 20 particles arbitrarily selected therefrom is taken as the average crystal particle diameter. In a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), 50 crystal grains adjacent to each other are selected, the longest portion of each crystal grain is defined as a grain diameter, the length thereof is measured, and the average value thereof is defined as an average crystal grain diameter. The magnification of the TEM photograph can be changed depending on the measured particle size.
The ratio of the microcrystalline phase in the composite phase of the microcrystalline phase and the amorphous phase can be determined by (a) Differential Scanning Calorimetry (DSC) or (b) X-ray diffraction measurement. Differential Scanning Calorimetry (DSC) and X-ray diffraction measurements were the same as described for negative electrode material 3 above.
(aluminum and element A)
Al and the element A (Mg or Mg and Si) are basic elements for occluding lithium. When the atomic ratio x of the element a is 0.9 or more, microcrystallization is difficult, and the cycle life and the rate characteristics of the secondary battery are reduced. A more preferable range of the atomic ratio x is 0.3. ltoreq. x.ltoreq.0.8.
The total atomic ratio of Al and the element A is in the range of 50 to 95 atomic%. When the total atomic ratio is less than 50 atomic%, the lithium storage energy of the negative electrode material decreases, and the discharge capacity, cycle life, and rate characteristics of the secondary battery are difficult to improve. On the other hand, when the total atomic ratio exceeds 95 atomic%, the negative electrode material hardly causes a lithium release reaction. The total atomic ratio is more preferably 70 to 90 atomic%.
(element M)
The three elements of Al, element a and element M promote the refinement of crystal grains. The element M can suppress micronization in the case of storing and releasing lithium in the negative electrode material. When the atomic ratio b of the element M is less than 5 atomic%, it is difficult to refine the crystal grains. On the other hand, when the atomic ratio b of the element M is more than 40 atomic%, the discharge capacity of the secondary battery is significantly reduced. The atomic ratio b of the element M is more preferably in the range of 7 to 35 atomic%.
(element M')
Specific examples of the rare earth elements are the same as those described for the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
For the same reason as in the negative electrode material 3, it is preferable that the element M' is contained in an atomic ratio of 10 atomic% or less. The atomic ratio c is more preferably 8 atomic% or less. For the same reason as that of the negative electrode material 3, the lower limit of the atomic ratio c is preferably 0.01 atomic%.
(element T)
The reason why the atomic ratio d of the element T is 20 atomic% or less is the same as that described for the negative electrode material 3. A more preferable range of the atomic ratio d is 15 atomic% or less.
In the nonaqueous electrolyte secondary battery having the negative electrode material of the present invention 4, the alloy composition contained in the negative electrode material does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may change the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (8).
The negative electrode material 4 can be produced by any of the above-described methods (1) to (3) for producing the negative electrode material 3.
The negative electrode material for a nonaqueous electrolyte battery according to the present invention 1 or 2 can be used to obtain a nonaqueous electrolyte battery in which the discharge capacity and the charge/discharge cycle life are improved, a higher discharge capacity can be obtained when the discharge rate is increased, and the maximum discharge capacity can be obtained with a smaller number of charge/discharge cycles. In addition, the negative electrode material 1 or 2 can improve the charge/discharge cycle life because the metal structure thereof is substantially composed of an amorphous phase, and extension in a single direction of the crystal lattice during lithium occlusion is alleviated, and micronization is suppressed.
The negative electrode material for a nonaqueous electrolyte battery according to the present invention 3 or 4 can be used to obtain a nonaqueous electrolyte battery in which the discharge capacity and the charge/discharge cycle life are improved, a higher discharge capacity can be obtained when the discharge rate is increased, and the maximum discharge capacity can be obtained with a smaller number of charge/discharge cycles. Further, the negative electrode material 3 or 4 can improve the charge/discharge cycle life because it has a metal structure containing a microcrystalline phase having an average crystal particle diameter of 500nm or less, and this metal structure alleviates deformation caused by lattice expansion accompanying lithium occlusion, and suppresses micronization.
Since the alloy constituent elements of the negative electrode materials 1 to 4 for nonaqueous electrolyte batteries do not contain lithium, the negative electrode materials are simple in element treatment during synthesis, and the negative electrode materials are synthesized by a liquid quenching method without risks such as sparking and the like, and thus mass production is facilitated. In an alloy system not containing a lithium alloy, the activation energy of an amorphous phase and a metastable opposing stable phase is high or the grain growth of a microcrystalline phase is slow, so that the crystal structure itself is stable and is advantageous for the cycle life of the electrode characteristics. In addition, the manufacturing yield of the negative electrode material is improved because the negative electrode material is hardly affected by the fluctuation of the heat treatment conditions.
Next, the negative electrode materials 5 to 8 for nonaqueous electrolyte batteries of the present invention will be described.
< negative electrode Material for nonaqueous electrolyte Battery 5>
The negative electrode material 5 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (5): [ (Al)1-xSix)aMbM’cTd]yLiz… … (5), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z each satisfy a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z.50 atomic%.
As the metal structure substantially composed of an amorphous phase, a structure in which a peak due to a crystalline phase does not appear in X-ray diffraction can be exemplified.
(aluminum and Si)
Al and Si are basic elements for occluding lithium. The reason why the atomic ratio x of Si is 0.75 or less is the same as that described in the above negative electrode material 1. The atomic ratio x is more preferably in the range of 0.3 to 0.75.
The reason why the total atomic ratio of Al and Si is in the range of 0.50 to 0.95 is the same as that described for the negative electrode material 1. The total atomic ratio is more than 0.67 and less than 0.90, preferably 0.7 to 0.88.
(element M)
The reason why the atomic ratio b of the element M is in the range of 0.05 to 0.4 is the same as that described for the negative electrode material 1. The atomic ratio b of the element M is more preferably in the range of 0.07 to 0.35.
(element M')
Specific examples of the rare earth elements are the same as those described for the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
For the same reason as described above for the negative electrode material 1, it is preferable that the element M' is contained in an atomic ratio of 0.1 or less. The range of the atomic ratio c is preferably 0.08 or less. For the same reason as in the case of the negative electrode material 1, the lower limit of the atomic ratio c is preferably 0.0001.
(element T)
The reason why the atomic ratio d of the element T is 0.20 or less is the same as that described for the negative electrode material 1. A more preferable range of the atomic ratio d is 0.15 or less.
(Li)
Lithium is an element that takes charge transfer of the nonaqueous electrolyte battery. Therefore, when lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The anode material 5 is easily activated as compared with the anode material 1, and therefore, the maximum discharge capacity can be obtained earlier in the charge-discharge cycle.
However, in the case where the constituent elements do not contain lithium as in the negative electrode material 1, it is necessary to use a lithium-containing compound such as a lithium composite metal oxide for the positive electrode active material. The negative electrode material 5 can use a compound containing no lithium in the constituent elements as a positive electrode active material, which can widen the kinds of usable positive electrode active materials. However, if the lithium content z exceeds 50 atomic%, amorphization becomes difficult. The lithium content z is more preferably 25 atomic% or less.
The negative electrode material 5 can be produced by a liquid quenching method, a mechanical alloying method, a mechanical milling method, a gas atomization method, a rotating disk method, a rotating electrode method. These methods were carried out under the conditions described for the negative electrode material 1.
< negative electrode Material 6 for nonaqueous electrolyte Battery >
The negative electrode material 6 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (6): [ (Al)1-xAx)aMbM’cTd]yLiz… … (6) wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each a + b + C + d ═ 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.ltoreq.0.9, y + z ═ 100 atomic%, 0. ltoreq. z.ltoreq. 50 atomic%.
As the metal structure substantially composed of an amorphous phase, a structure in which a peak due to a crystalline phase does not appear in X-ray diffraction can be exemplified.
(aluminum and element A)
Al and element a are basic elements for occluding lithium. The reason why the atomic ratio x of the element a is 0.9 or less is the same as that described for the negative electrode material 2. A more preferable range of the atomic ratio x is 0.3. ltoreq. x.ltoreq.0.8.
The reason why the total atomic ratio of Al and the element a is in the range of 0.50 to 0.95 is the same as that described for the negative electrode material 2. The total atomic ratio is more preferably in the range of 0.7 to 0.9.
(element M)
The reason why the atomic ratio b of the element M is in the range of 0.05 to 0.4 is the same as that described for the negative electrode material 2. The atomic ratio b of the element M is more preferably in the range of 0.07 to 0.35.
(element M')
Specific examples of the rare earth elements are the same as those described for the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
For the same reason as in the negative electrode material 2, it is preferable that the element M' is contained in an atomic ratio c of 0.1 or less. The range of the atomic ratio c is preferably 0.08 or less. For the same reason as in the case of the negative electrode material 2, the lower limit of the atomic ratio c is preferably 0.0001.
(element T)
The reason why the atomic ratio d of the element T is 0.20 or less is the same as that described for the negative electrode material 2. A more preferable range of the atomic ratio d is 0.15 or less.
(Li)
When lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The anode material 6 is easily activated as compared with the anode material 2, and therefore, the maximum discharge capacity can be obtained earlier in the charge-discharge cycle.
The negative electrode material 6 can use a compound containing no lithium in the constituent elements as a positive electrode active material, thus widening the usable positive electrode active material classes. However, if the lithium content z exceeds 50 atomic%, amorphization becomes difficult. The lithium content z is more preferably 25 atomic% or less.
The negative electrode material 6 can be produced by a liquid quenching method, a mechanical alloying method, a mechanical milling method, a gas atomization method, a rotating disk method, a rotating electrode method. These methods can be carried out under the same conditions as described for the negative electrode material 1.
< negative electrode Material 7 for nonaqueous electrolyte Battery >
The negative electrode material 7 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (7): [ (Al)1-xSix)aMbM’cTd]yLiz… … (7) wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z each satisfy the relationship a + b + C + d 1, a 0.5. ltoreq. a.ltoreq.0.95, b 0.05. ltoreq.0.4, c.ltoreq.01, d 0. ltoreq.0.2, x 0. ltoreq.0.75, y + z 100 at%, and z 0. ltoreq.50 at% and having an average crystal grain size of 500nm or less.
The negative electrode material 7 may be substantially composed of the above-described microcrystalline phase, or may be composed of a composite phase of the above-described microcrystalline phase and an amorphous phase.
The microcrystalline phase may be composed of an intermetallic compound, a compound having a nonstoichiometric composition, or an alloy having a nonstoichiometric composition, and is preferably composed of a plurality of compound or alloy phases from the viewpoint of service life and capacity.
The reason why the average crystal grain size of the microcrystalline phase is 500nm or less is the same as that described for the negative electrode material 3. The average crystal grain size is more preferably in the range of 5nm to 500nm, still more preferably in the range of 5nm to 300 nm.
The average crystal grain size can be determined from the half width of the X-ray diffraction line according to the Scherrer formula. A Transmission Electron Microscope (TEM) photograph may be taken, and the average of the maximum particle diameters of 20 particles arbitrarily selected therefrom is taken as the average crystal particle diameter. In a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), 50 crystal grains adjacent to each other are selected, the longest portion of each crystal grain is defined as a grain diameter, the length thereof is measured, and the average value thereof is defined as an average crystal grain diameter. The magnification of the TEM photograph can be changed depending on the measured particle size.
The ratio of the microcrystalline phase in the composite phase of the microcrystalline phase and the amorphous phase can be determined by (a) Differential Scanning Calorimetry (DSC) or (b) X-ray diffraction measurement. Differential Scanning Calorimetry (DSC) and X-ray diffraction measurements were the same as described for negative electrode material 3 above.
(aluminum and Si)
Al and Si are basic elements for occluding lithium. The reason why the element a is contained at the atomic ratio x of 0.75 or less is the same as that described in the above negative electrode material 3. The atomic ratio x is more preferably in the range of 0.3 to 0.75.
The reason why the total atomic ratio of Al and Si is in the range of 0.50 to 0.95 is the same as that described for the negative electrode material 3. The total atomic ratio is more than 0.67 and less than 0.90, preferably 0.70 to 0.88.
(element M)
The reason why the atomic ratio b of the element M is 0.05 to 0.40 is the same as that of the negative electrode material 3. The atomic ratio b of the element M is more preferably in the range of 0.07 to 0.35.
(element M')
Specific examples of the rare earth elements are the same as those described for the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
For the same reason as in the case of the negative electrode material 3, the element M' is contained at an atomic ratio of 0.1 or less, and a more preferable range of the atomic ratio c is 0.08 or less. For the same reason as in the case of the negative electrode material 3, the lower limit of the atomic ratio c is preferably 0.0001.
(element T)
The reason why the atomic ratio d of the element T is 0.20 or less is the same as that described for the negative electrode material 3. A more preferable range of the atomic ratio d is 0.15 or less.
(Li)
When lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The negative electrode material 7 is more easily activated than the negative electrode material 3, and therefore, the maximum discharge capacity can be obtained earlier in the charge-discharge cycle.
The negative electrode material 7 can use a compound containing no lithium in the constituent elements as a positive electrode active material, which can widen the types of usable positive electrode active materials. However, if the lithium content z exceeds 50 atomic%, microcrystallization is difficult. The lithium content z is more preferably 25 atomic% or less.
The negative electrode material 7 can be produced by any of the production methods (1) to (3) described for the negative electrode material 3.
< negative electrode Material 8 for nonaqueous electrolyte Battery >
The negative electrode material 8 for a nonaqueous electrolyte battery comprises a negative electrode having the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.ltoreq.0.9, y. ltoreq.100 atomic%, 0. z.ltoreq.50 atomic%.
The negative electrode material 8 may be substantially composed of the above-described microcrystalline phase, or may be composed of a composite phase of the above-described microcrystalline phase and an amorphous phase.
The microcrystalline phase may be composed of an intermetallic compound, a compound having a nonstoichiometric composition, or an alloy having a nonstoichiometric composition, and is preferably composed of a plurality of compound or alloy phases from the viewpoint of service life and capacity.
The reason why the average crystal grain size of the microcrystalline phase is 500nm or less is the same as that described for the negative electrode material 3. The average crystal grain size is more preferably in the range of 5nm to 500nm, still more preferably in the range of 5nm to 300 nm.
The average crystal grain size can be determined from the half width of the X-ray diffraction line according to the Scherrer formula. A Transmission Electron Microscope (TEM) photograph may be taken, and the average of the maximum particle diameters of 20 particles arbitrarily selected therefrom is taken as the average crystal particle diameter. In a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), 50 crystal grains adjacent to each other are selected, the longest portion of each crystal grain is defined as a grain diameter, the length thereof is measured, and the average value thereof is defined as an average crystal grain diameter. The magnification of the TEM photograph can be changed depending on the measured particle size.
The ratio of the microcrystalline phase in the composite phase of the microcrystalline phase and the amorphous phase can be determined by (a) Differential Scanning Calorimetry (DSC) or (b) X-ray diffraction measurement. Differential Scanning Calorimetry (DSC) and X-ray diffraction measurements were the same as described for negative electrode material 3 above.
(aluminum and element A)
A1 and element a (Mg or Mg and Si) are basic elements for occluding lithium. The reason why the element a is contained in the atomic ratio x of 0.9 or less is the same as that described for the negative electrode material 4. A more preferable range of the atomic ratio x is 0.3. ltoreq. x.ltoreq.0.8.
The reason why the total atomic ratio of Al and the element a is in the range of 0.50 to 0.95 is the same as that described for the negative electrode material 4. The total atomic ratio is more preferably in the range of 0.7 to 0.9.
(element M)
The reason why the atomic ratio b of the element M is 0.05 to 0.40 is the same as that of the negative electrode material 4. The atomic ratio b of the element M is more preferably in the range of 0.07 to 0.35.
(element M')
Specific examples of the rare earth elements are the same as those described for the negative electrode material 1. Among them, La, Ce, Pr, Nd, Sm are preferred.
For the same reason as in the case of the negative electrode material 3, the element M' is contained at an atomic ratio of 0.1 or less. The preferable range of the atomic ratio c is 0.08 or less. For the same reason as in the case of the negative electrode material 3, the lower limit of the atomic ratio c is preferably 0.0001.
(element T)
The reason why the atomic ratio d of the element T is 0.20 or less is the same as that described in the above negative electrode material 3. A more preferable range of the atomic ratio d is 0.15 or less.
(Li)
When lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The negative electrode material 8 is easily activated as compared with the negative electrode material 4, and therefore, the maximum discharge capacity can be obtained earlier in the charge-discharge cycle.
The negative electrode material 8 can use a compound containing no lithium in the constituent elements as a positive electrode active material, thus widening the usable positive electrode active material class. However, if the lithium content z exceeds 50 atomic%, microcrystallization is difficult. The lithium content z is more preferably 25 atomic% or less.
The negative electrode material 8 can be produced by any of the production methods (1) to (3) described for the negative electrode material 3.
By using the negative electrode material 5 or 6 for a nonaqueous electrolyte battery of the present invention, a nonaqueous electrolyte battery having improved discharge capacity and charge/discharge cycle life, a higher discharge capacity even when the discharge rate is increased, and a maximum discharge capacity with a smaller number of charge/discharge cycles can be obtained. In addition, the negative electrode material 5 or 6 can improve the charge/discharge cycle life because the metal structure thereof is substantially composed of an amorphous phase, and extension in a single direction of the crystal lattice during lithium occlusion is alleviated, and micronization is suppressed.
By using the negative electrode material 7 or 8 for a nonaqueous electrolyte battery of the present invention, a nonaqueous electrolyte battery can be obtained in which the discharge capacity and the charge/discharge cycle life are improved, a higher discharge capacity can be obtained when the discharge rate is increased, and the maximum discharge capacity can be obtained with a smaller number of charge/discharge cycles. Further, the negative electrode material 7 or 8 can improve the charge/discharge cycle life because it has a metal structure containing a microcrystalline phase having an average crystal particle diameter of 500nm or less, and this metal structure alleviates deformation caused by lattice expansion accompanying lithium occlusion, and suppresses micronization.
< negative electrode Material 9 for nonaqueous electrolyte Battery >
The negative electrode material for a nonaqueous electrolyte battery of the present invention 9 is a negative electrode material for occluding and releasing lithium, and is characterized in that at least one exothermic peak is present in the range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) in which the temperature rise rate is 10 ℃/min, and a diffraction peak based on a crystal phase is present in X-ray diffraction.
The thermal process from the non-equilibrium state to the equilibrium state was investigated by Differential Scanning Calorimetry (DSC). The peak of heat generation in Differential Scanning Calorimetry (DSC) corresponds to the change in heat from a non-equilibrium state to a state more stable than the phase. A negative electrode material which exhibits at least one exothermic peak in the range of 200 to 450 ℃ when a Differential Scanning Calorimetry (DSC) is performed at a temperature rise rate of 10 ℃/min after X-ray diffraction measurement based on a diffraction peak of a crystalline phase occurring in X-ray diffraction, comprises an non-equilibrium phase which is not an amorphous phase, and can improve the charge-discharge cycle life of a secondary battery. The improvement in charge-discharge cycle life may be caused by the increased diffusion rate of lithium ions due to the above-mentioned non-equilibrium phase. In order to further improve the charge-discharge cycle life, the temperature at which the exothermic peak occurs is desirably in the range of 220 to 400 ℃.
The number of exothermic peaks is not particularly limited, since it varies depending on the composition. That is, the number of steps is not particularly limited since the process from the non-equilibrium state to the equilibrium state varies depending on the composition, and there are approximately 1 to 4 heat release peaks.
The non-equilibrium phase contained in the negative electrode material of the invention 9 has a cubic fluorite structure or an inverted fluorite structure. The lattice constant of this crystal phase is 5.42-6.3. The reason for this is that if the lattice constant is less than 5.42, a high capacity may not be obtained. On the other hand, if the lattice constant is larger than 6.3. ANGSTROM, it is difficult to sufficiently improve the charge-discharge cycle life. The lattice constant is preferably in the range of 5.45 to 6, more preferably 5.5 to 5.9.
The nonequilibrium phase of the cubic fluorite structure or the inverted fluorite structure having a lattice constant of 5.42-6.3 is easily obtained when the nonequilibrium phase composition contains Al, Si, Ni, or Al, Si, Co. In this composition, a part of Ni or Co may be substituted with another element (e.g., Fe, Nb, or La), thereby obtaining the above-described crystal structure. In the non-equilibrium phase having such a crystal structure, it is more preferable to replace Si in the solid-dissolved Al with another element (e.g., Co, Fe, Cu, Mn, Ti, Zr, Hf, Nb, Ta, Cr, La, Ce, Pr, Nd) 2Ni phase, Si in solid solution with Al2Co phase, the above Si2Ni or Si of the Ni phase, or replacement of the Si with another element (e.g., Fe, Ni, Nb, La)2Co or Si of the Co phase. The kind of the non-equilibrium phase contained in the alloy may be one kind or two or more kinds.
The average crystal grain size of the non-equilibrium phase, which is not an amorphous phase, contained in the negative electrode material of the invention 9 is in the range of 5 to 500 nm. The reason for this is that when the average crystal grain size is less than 5nm, the crystal grains are too fine, and lithium occlusion is difficult, and a high capacity cannot be obtained. On the other hand, when the average crystal particle size is larger than 500nm, the negative electrode material is micronized, and the charge-discharge cycle life is reduced. The average crystal grain size is more preferably 10 to 400 nm.
The average crystal grain size of the non-equilibrium phase is determined by selecting 50 crystal grains adjacent to each other in a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), and calculating the average value of the maximum length of each crystal grain as the grain size. The magnification of the TEM photograph can be changed depending on the measured particle size.
< negative electrode Material 10 for nonaqueous electrolyte Battery >
The negative electrode material for a nonaqueous electrolyte battery of the present invention 10 comprises a first phase which is an intermetallic compound phase containing two or more elements that can be alloyed with lithium, and a second phase mainly containing an element that can be alloyed with lithium, and is characterized in that a diffraction peak (first phase) derived from the intermetallic compound phase is exhibited when the d value is at least 3.13 to 3.64_ and 1.92 to 2.23_ in a powder X-ray diffraction measurement, and a diffraction peak derived from the second phase is exhibited when the d value is at least 2.31 to 2.40 _.
In the powder X-ray diffraction measurement, it is preferable that the first phase exhibits diffraction peaks at d values of at least 3.13 to 3.64. ang. and 1.92 to 2.23. ang. Meanwhile, the second phase exhibits a diffraction peak at a d value of at least 2.31 to 2.40. When no diffraction peak appears at any of 3.13 to 3.64, 1.92 to 2.23, and 2.31 to 2.40, the discharge capacity, the charge-discharge cycle life, or the discharge rate characteristic is lowered.
From the viewpoint of further improving the discharge rate characteristics of the battery, it is desirable that the first phase further exhibits diffraction peaks in the powder X-ray diffraction measurement at d values of 1.64 to 1.90, 1.36 to 1.58, and 1.25 to 1.45, respectively. It is desirable that the second phase further exhibits diffraction peaks in powder X-ray diffraction measurement at d values of 2.00 to 2.08, 1.41 to 1.47, and 1.21 to 1.25, respectively.
The d value in the powder X-ray diffraction measurement of the first phase and the second phase may vary depending on the composition or the state of quenching, the subsequent heat treatment, and the like.
< negative electrode Material 11 for nonaqueous electrolyte Battery >
The negative electrode material for a nonaqueous electrolyte battery of the present invention 11 comprises a first phase in which at least a part of intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm, which contain two or more elements alloyable with lithium, are isolated from each other and precipitated, and a second phase mainly composed of an element alloyable with lithium and precipitated in a state of being embedded between the isolated crystal particles.
The metal structure of the negative electrode material of the invention 11 will be described with reference to fig. 5.
The metal structure of the negative electrode material of the present invention 11 includes a first phase in which the intermetallic compound crystal particles 21 are isolated and precipitated from each other, and a second phase 22 in which the isolated intermetallic compound crystal particles 21 are embedded and precipitated. The metal structure has a sea-island structure in which isolated crystal grains 21 are islands and the second phase 22 corresponds to a sea. In fig. 5, only islands in which the intermetallic compound crystal particles 21 are isolated and precipitated are shown, but two or more intermetallic compound crystal particles 21 may be precipitated adjacent to each other in the metal structure (in the case where 2 or more islands are in contact with each other).
When the second phase 22 has a continuous network structure, the binding force of the first phase to the second phase can be increased, and therefore, deformation accompanying the occlusion and release of lithium in the second phase can be suppressed. However, since a plurality of intermetallic compound crystal particles are likely to precipitate in a state of being adjacent to each other or the second phase is likely to aggregate by the heat treatment, the network structure is cut as a result of the aggregation of the second phase by the heat treatment, and a part of the second phase 22 is isolated, which is also included in the present invention. When the second phase 22 is isolated, the number of islands per unit area decreases, and the distance L between the islands tends to increase.
(first phase)
The reason why the average crystal grain size of the intermetallic compound crystal grains is defined to be within the above range is as follows. When the average crystal grain size is less than 5nm, the crystal grains are too fine to cause difficulty in lithium occlusion, and a high capacity cannot be obtained. On the other hand, when the average crystal grain size is larger than 500nm, deformation accompanying the lithium occlusion and release of the second phase is hardly absorbed by the intermetallic compound phase, and therefore the negative electrode material is rapidly pulverized, resulting in a decrease in charge-discharge cycle life. The average crystal grain size is more preferably 10 to 300 nm.
The average crystal grain size of the intermetallic compound crystal grains is determined by selecting 50 metal compound crystal grains adjacent to each other in a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), measuring the maximum length of each crystal grain, and calculating the average value thereof. The magnification of the TEM photograph can be changed depending on the measured particle size. When 2 or more intermetallic compound crystal particles are in contact with each other, the maximum length of each intermetallic compound crystal particle dispersed at the grain boundary is measured as the particle diameter.
1μm2The reason why the number of the intermetallic compound crystal particles in (1) is in the range of 10 to 2000 is as follows. 1 μm 2When the number of the intermetallic compound crystal particles in (b) is 10 or less, the binding force of the first phase to the second phase is weak, and the deformation accompanying the occlusion and release of lithium in the second phase becomes larger, so that the negative electrode material is rapidly pulverized, and the charge-discharge cycle life is reduced. On the other hand, 1 μm2When the number of intermetallic compound crystal particles in (b) is 2000 or more, the lithium storage characteristics of the negative electrode material decrease, and a high capacity cannot be obtained. To make 1 μm2The number of intermetallic compound crystal particles in the negative electrode material is in the range of 10 to 2000, and the negative electrode material can sufficiently suppress expansion and contraction accompanying the absorption and release of lithium in the second phase, suppress micronization of the negative electrode material, and improve the charge-discharge cycle life, and more preferably, the number of the intermetallic compound crystal particles is in the range of 20 to 1800.
The reason why the average value of the distance L between the intermetallic compound crystal particles is 500nm or less is as follows. When the average value of the distance L between the crystal particles is more than 500nm, the first phase is difficult to restrain the second phase, and the negative electrode material is quickly micronized along with the absorption and release of lithium of the second phase, so that the charge-discharge cycle life is reduced. The average value of the distance L between the intermetallic compound crystal particles is set to 500nm or less, the second phase is confined by the intermetallic compound crystal particles surrounding the second phase, expansion and contraction accompanying the release of lithium occlusion by the second phase can be sufficiently suppressed, the negative electrode material can be suppressed from being micronized, and the charge-discharge cycle life can be improved. The average distance between crystal grains is preferably 400nm or less, particularly preferably 300nm or less.
The intermetallic compound crystal particles have cubic fluorite (CaF)2) Structure or inverse fluorite structure of cubic system. The lattice constant of the crystal particles is 5.42-6.3. The reason for this is that if the lattice constant is less than 5.42, a high capacity may not be obtained. On the other hand, if the lattice constant is larger than 6.3. ANGSTROM, it is difficult to sufficiently improve the charge-discharge cycle life. The lattice constant is set to be 5.42-6.3-inclusive, and the absorption and release of lithium associated with the second phase can be sufficiently suppressedAnd the generated expansion and contraction can inhibit the micronization of the negative electrode material and prolong the charge-discharge cycle life of the secondary battery. The lattice constant is more preferably in the range of 5.45 to 6, still more preferably 5.5 to 5.9.
In the crystal structure of the intermetallic compound crystal particles, it is preferable that Al is solid-dissolved in fluorite (CaF)2) Form Si2Crystal structure A in Ni lattice, and solid solution of Al in fluorite-type Si2Crystal structure B in Co lattice. Si of the above crystal structure A2A part of Ni or Si in the Ni lattice may be substituted with other elements (e.g., Co, Fe, Cu, Mn, Ti, Zr, Hf, Nb, Ta, Cr, La, Ce, Pr, Nd). On the other hand, Si of the above crystal structure B2A part of Co or Si in the Co lattice may be substituted with other elements (e.g., Fe, Ni, Nb, La). The intermetallic compound crystal particles having the crystal structure a and the intermetallic compound crystal particles having the crystal structure B may coexist in the anode material of the invention 11.
When the first phase is subjected to Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, the first phase shows at least one non-equilibrium phase with an exothermic peak in the range of 200 to 450 ℃. This structure can improve the charge-discharge cycle life of the secondary battery. The temperature range of exothermic peak is 220-400 ℃.
(second phase)
The occupancy of the second phase in the negative electrode material is preferably in the range of 1 to 50%. When the occupancy of the second phase is less than 1%, lithium storage is difficult, and a high capacity cannot be obtained. On the other hand, if the occupancy of the second phase is more than 50%, it is difficult to suppress the micronization of the negative electrode material, and a long service life may not be obtained. The occupancy is more preferably 5 to 40%.
The occupancy ratio of the second phase in the negative electrode material was measured by the method described below. That is, in one field of view (magnification is changed depending on particle diameter, for example, magnification is 10 ten thousand times) of the TEM photograph, the area ratio (%) of the first phase is obtained by image processing in a region (area 100%) containing at least 50 intermetallic compound crystal particles, and the area ratio (%) of the first phase is removed from the area (100%) of the entire region to obtain the area ratio of the second phase, that is, the occupancy of the second phase in the negative electrode material. When 2 or more intermetallic compound crystal particles are in contact with each other, the number of the intermetallic compound crystal particles dispersed at the grain boundaries is counted without counting one intermetallic compound crystal particle.
The first phase preferably exhibits diffraction peaks at d values of at least 3.13 to 3.64 a and 1.92 to 2.23 a in powder X-ray diffraction measurement. Meanwhile, the second phase preferably exhibits a diffraction peak at a d value of at least 2.31 to 2.40. This structure can further improve the discharge rate characteristics of the battery. In the powder X-ray diffraction measurement, the first phase preferably has diffraction peaks at d values of 1.64 to 1.90, 1.36 to 1.58, and 1.25 to 1.45, respectively. The second phase preferably exhibits diffraction peaks at d values of 2.00 to 2.08, 1.41 to 1.47, and 1.21 to 1.25, respectively.
The first phase and the second phase of the negative electrode material for nonaqueous electrolyte batteries of the invention 10 and 11 preferably have the following compositions.
(composition of the first phase)
As the element alloyable with lithium contained In the first phase, Al, In, Pb, Ga, Mg, Sb, Bi, Sn, Zn are preferable. As an element capable of forming an intermetallic compound with an element alloyable with lithium, Ni or Co, or both Ni and Co are used. A part of Ni may be substituted with other elements. As other elements, transition metal elements such as Co, Fe, and Nb, and rare earth elements such as La can be used. On the other hand, other elements that substitute for Co include transition metal elements such as Fe and Nb, and rare earth elements such as La. The kind of other elements is one or more than two.
(composition of second phase)
The second phase mainly contains an element that can be alloyed with lithium, and the other elements may be dissolved in an amount of 10 atomic% or less. Elements alloyable with lithium include Al, In, Pb, Ga, Mg, Sb, Bi, Sn, Zn, and the like. Among them, Al is preferred. It is desirable that the element solid-solved in the second phase is an element capable of alloying with lithium, since the lithium occlusion release amount of the second phase can be increased. The solid solution of the M element and M' element such as Ni and Co in the second phase improves the mechanical strength to suppress the effect of micronization.
The negative electrode material for nonaqueous electrolyte batteries according to the present invention is an alloy containing Al, Si or Si and Mg as an element N1, at least one element selected from Ni and Co as an element N2, and at least one element selected from In, Bi, Pb, Sn, Ga, Sb, Zn, Fe, Cu, Mn, Cr, Ti, Zr, Nb, Ta and a rare earth element as an element N3. When the Al content in the alloy is h atom%, the N1 content in the alloy is i atom%, the N2 content in the alloy is j atom%, and the N3 content in the alloy is k atom%, h, i, j and k respectively satisfy 12.5-95 h, 0-71 i, 5-40 j and 0-20 k.
The reason why the contents of Al, N1, N2 and N3 in the alloy are limited to the above ranges is as follows.
(Al)
When the Al content h in the alloy is 12.5 atomic% or less, precipitation of the second phase (sea) may become difficult, and the charge-discharge cycle life may be reduced. On the other hand, when the Al content h in the alloy is 95 atomic% or more, the formation of the first phase (island) is extremely small, and the capacity and the charge-discharge cycle life may be reduced. The Al content is more preferably 20 to 85 atomic%.
(element N1)
When Si is not contained in the alloy, the capacity is significantly reduced, and a high capacity cannot be obtained, and a long life cannot be obtained without precipitation of the first phase (island) suitable for a long life. On the other hand, when the content of the element N1 in the alloy exceeds 71 atomic%, although the capacity increases, it may be difficult to form a second phase (sea). When the second phase (sea) is not formed, the charge-discharge cycle life is greatly reduced, and the number of charge-discharge cycles or the rate characteristics required to achieve the maximum capacity are deteriorated. The content i of the element N1 is more preferably 10 to 60 atomic%.
(element N2)
When the content j of the element N2 in the alloy is less than 5 atomic%, the first phase is difficult to form and the charge-discharge cycle life is reduced. On the other hand, when the content j of the element N2 in the alloy exceeds 40 atomic%, the second phase is hardly formed and the entire first phase occupies the second phase. At this time, the number of charge and discharge cycles or the rate characteristic required to reach the maximum capacity is deteriorated. The content i of the element N2 is more preferably 12 to 35 atomic%.
(element N3)
When the content k of the element N3 In the alloy is 20 atomic%, the charge-discharge cycle life is reduced when the element N3 is In, Bi, Pb, Sn, Ga, Mg, Sb or Zn. On the other hand, when the element N3 is Fe, Cu, Mn, Cr, Ti, Zr, Nb, Ta, Cr or a rare earth element, the capacity decreases. The content k of the element N3 is more preferably in the range of 15 atomic% or less.
More preferably, the alloy composition is represented by the above formulae (3) and (7), the composition represented by the above formulae (4) and (8) is a composition in which the element A is Si or Mg, and the following formula (9): (Al)1-m-nSimM1n)pM2qM3rM4s… … (9).
In the formula (9), M1 represents at least one element selected from the group consisting of In, Bi, Pb, Sn, Ga, Mg, Sb and Zn, M2 represents at least one element selected from the group consisting of Ni and Co, M3 represents at least one element selected from the group consisting of Fe, Cu, Mn and Cr, M4 represents at least one element selected from the group consisting of Ti, Zr, Nb, Ta and rare earth elements, and the atomic ratios M, n, p, q, r and s are such that p + q + r + s is 100 atomic%, p is 60 atomic% or more and 90 atomic% or less, q is 10 atomic% or more and 40 atomic% or less, r is 0 or more and 10 atomic% or less, s is 0 or more and 10 atomic% or less, M is 0 < 0.75, and n is 0 or more and 0.2, respectively.
< negative electrode Material 12 for nonaqueous electrolyte Battery >
The negative electrode material for a nonaqueous electrolyte battery of the present invention 12 includes an alloy containing a microcrystalline phase having an average crystal grain diameter of 500nm or less and having a composition represented by any one of the above general formulae (3), (4), (7), and (8). Except for the case where the element A in the compositions represented by the general formulae (4) and (8) is Mg.
The negative electrode material 12 includes a negative electrode material substantially composed of the above-described microcrystalline phase, a negative electrode material substantially composed of a composite phase of the above-described microcrystalline phase and an amorphous phase, a negative electrode material mainly composed of the above-described microcrystalline phase, and the like.
The microcrystalline phase is composed of intermetallic compounds, but may also be composed of compounds of non-stoichiometric composition or of alloys of non-stoichiometric composition.
When the average crystal particle size of the microcrystalline phase is 500nm or more, the negative electrode material is rapidly micronized, and thus the charge/discharge life cycle life is reduced. Although the average crystal grain size is small, micronization can be suppressed, when the average crystal grain size is less than 5nm, the occlusion of lithium becomes difficult, and the discharge capacity of the secondary battery decreases. Therefore, the average crystal grain size is preferably in the range of 5nm to 500nm, more preferably in the range of 5nm to 300 nm.
The average crystal grain size of the microcrystalline phase is determined by selecting 50 crystal grains adjacent to each other in a Transmission Electron Microscope (TEM) photograph (for example, 10 ten thousand times), measuring the maximum length of each crystal grain, and calculating the average value thereof. The magnification of the TEM photograph can be changed depending on the measured particle size.
The microcrystalline phase has cubic fluorite (CaF) 2) Structure or cubic inverted fluorite structure. The lattice constant of this crystal phase is 5.42-6.3. The microcrystalline phase having the cubic fluorite structure and the inverse fluorite structure with the lattice constant of more than 5.42 < 6.3 < is not an amorphous phase but an unbalanced phase, which can improve the charge-discharge cycle life and discharge capacity of the secondary battery. When the lattice constant is less than 5.42, a high capacity may not be obtained. On the other hand, when the lattice constant is more than 6.3, it is difficult to sufficiently improve the charge-discharge cycle life. The lattice constant is more preferably in the range of 5.45 to 6, still more preferably 5.5 to 5.9.
Having cubic fluorite (CaF)2) In the microcrystalline phase of the structure, Si in which Al is dissolved in a solid is preferred2Ni phase and solidSi dissolved in Al2Co phase of the above Si2The Ni or Si of the Ni phase may be partially substituted with other elements (e.g., Co, Fe, Cu, Mn, Ti, Zr, Hf, Nb, Ta, Cr, La, Ce, Pr, Nd), and the above-mentioned Si2A part of Co or Si in the Co phase may be substituted with other elements (e.g., Fe, Ni, Nb, La). These microcrystalline phases are not amorphous phases but are nonequilibrium phases. These microcrystalline phases can increase the diffusion rate of lithium ions of the negative electrode material, and thus can improve the charge-discharge cycle life of the secondary battery.
When Differential Scanning Calorimetry (DSC) is performed on the negative electrode material of the invention 12 at a temperature rise rate of 10 ℃/min, at least one nonequilibrium phase with an exothermic peak appears in a temperature range of 200-450 ℃. The negative electrode material can improve the charge-discharge cycle life of the secondary battery. The temperature range in which the exothermic peak appears is preferably 220 to 400 ℃.
The anode material of the invention 12 shows a diffraction peak from Al when the d value is at least 2.31 to 2.40 in the powder X-ray diffraction measurement, and shows a diffraction peak from an intermetallic compound containing Al and Si when the d value is at least 3.13 to 3.64 and 1.92 to 2.23. The resulting electrolyte secondary battery having such a structure is improved in discharge capacity, cycle life and discharge rate, and the number of charge/discharge cycles to achieve the maximum capacity is reduced.
In order to further improve the discharge rate characteristics of the nonaqueous electrolyte battery, it is preferable that a diffraction peak derived from Al is generated when the d value is 2.00 to 2.08-, 1.41 to 1.47-, and 1.21 to 1.25-in the powder X-ray diffraction measurement. It is also desirable that diffraction peaks from intermetallic compounds containing Al and Si occur at d values of 1.64 to 1.90, 1.36 to 1.58 and 1.25 to 1.45.
In the powder X-ray diffraction measurement, the d value at which a diffraction peak appears varies depending on the composition, the quenching state, or the subsequent process such as heat treatment.
The metal structure of the negative electrode material of the present invention 12 includes a first phase and a second phase, and the first phase contains Al. At least a part of the intermetallic compound crystal particles of Si and the element M are precipitated in isolation from each other, and the second phase is mainly a1 precipitated by being embedded between the isolated crystal particles. The second phase mainly composed of Al has a larger amount of lithium occlusion and release than the first phase, and the amount of deformation during occlusion and release is also increased. The metal structure having the above structure can relax deformation accompanying the absorption and release of lithium in the second phase, suppress the micronization of the negative electrode material, and further improve the charge-discharge cycle life, because the second phase can be constrained by the first phase. Elements other than Al may be dissolved in the second phase mainly composed of Al in an amount of 10 atomic% or less. The solid solution of the M element such as Ni and Co and the M' element in the second phase suppresses micronization by improving mechanical strength.
The negative electrode material of the invention 9-12 can be prepared by the following method.
A metal solution containing a first element, a second element and a third element is injected onto a single roll, and quenched so that the thickness of the metal solution becomes 10 to 500 [ mu ] m, and a metal structure containing a high-melting intermetallic compound phase containing the first to third elements and a second phase mainly composed of the first element and having a lower melting point than the intermetallic compound phase is solidified, whereby negative electrode materials 9 to 12 can be obtained.
The first element is at least one element selected from Al, In, Pb, Ga, Mg, Sb, Bi, Sn, Zn, the second element is at least one element selected from elements other than Al, In, Pb, Ga, Mg, Sb, Bi, Sn, Zn alloyable with lithium, and the third element is at least one element capable of forming an intermetallic compound with the first element and the second element.
(composition of Metal solution)
The metal solution can be obtained by the method described in the following (a) or (b).
(a) The first to third elements are mixed at a prescribed atomic ratio (at%), and the resulting mixture is melted to obtain a metal solution.
(b) An alloy having a desired composition is produced by a casting method using the first to third elements, and the obtained alloy is melted to obtain a metal solution.
Among the first elements, Al is preferred. When the anode material using Al as the first element is used, Si is preferably used as the second element. As the third element which can form an intermetallic compound with Al and Si, Ni and Co can be used. A part of the Ni may be substituted with other elements. As such other elements, transition metal elements such as Co, Fe and Nb, and rare earth elements such as La can be used. On the other hand, as other elements for replacing part of Co, transition metal elements such as Fe and Nb, and rare earth elements such as La can be used. The kind of the other element may be one or two or more.
Among the metal solutions containing the first to third elements, a metal solution containing a1, Si or Si and Mg as the element N1, at least one selected from Ni and Co as the element N2, and at least one selected from In, Bi, Pb, Sn, Ga, Sb, Zn, Fe, Cu, Mn, Cr, Ti, Zr, Nb, Ta, Cr and rare earth elements as the element N3 is preferable. When the Al content in the metal solution is h atom%, the element N1 content in the metal solution is i atom%, the element N2 content in the metal solution is j atom%, and the element N3 content in the metal solution is k atom%, the h, i, j, and k respectively satisfy the conditions that h is greater than or equal to 12.5 and less than or equal to 95, i is greater than or equal to 0 and less than or equal to 71, j is greater than or equal to 5 and less than or equal to 40, and k is greater than or equal to 0 and less than or equal to 20.
The thickness of the sheet can be made 10 to 500 μm by injecting the metal solution having the above composition onto a single roll and quenching the metal solution. And solidifying a metal structure having a high-melting intermetallic compound phase containing Al, the element N1 and the element N2, and a second phase mainly composed of Al and having a lower melting point than the intermetallic compound.
Of the compositions of the metal solutions, those represented by the above-mentioned formulae (3) and (7) are preferred, and those represented by the above-mentioned formulae (4) and (8) are those in which the element A is Si or Mg, and those represented by the above-mentioned formula (9).
The metal solution having a composition represented by the above formula (9) has fluorite (CaF)2) Form Si2Intermetallic compound phase of crystal structure in which Al is dissolved in Ni lattice or fluorite-type Si2An intermetallic compound phase having a crystal structure in which Al is dissolved in Co crystal lattice is precipitated as primary crystals.At the same time, the grain size of the intermetallic compound phase, the distance between the crystal grains, and the number of crystal grains per unit area can be optimized.
(intermetallic compound crystal particles)
The intermetallic compound crystal particles are composed of fluorite (CaF)2) Form Si2A crystal structure A in which Al is dissolved in a part of the lattice of Ni, and Si in which Al is dissolved in fluorite form2Crystal structure B in Co lattice. Si of the above crystal structure A2A part of Ni or Si in the Ni lattice may be substituted with other elements (e.g., Co, Fe, Cu, Mn, Ti, Zr, Hf, Nb, Ta, Cr, La, Ce, Pr, Nd). Si of the above crystal structure B2A part of Co or Si in the Co lattice may be substituted with other elements (e.g., Fe, Ni, Nb, La).
(second phase)
The second phase is mainly composed of the first element, but may contain 10 atomic% or less of other elements. In particular, when the second element is contained in the second phase in an amount of 10 atomic% or less, the monomer phase capacity can be increased, and therefore, it is preferable. The melting point of the second phase is lower than that of the first phase, and when the melting point of the second phase is equal to or higher than that of the intermetallic compound, the first phase is relatively difficult to precipitate as a primary crystal, and it is difficult to form the sea-island structure of the present invention.
The second phase is preferably mainly Al. The second phase mainly composed of Al contains 10 atomic% or less of M element and M' element such as Ni and Co. When the M element and the M' element such as Ni and Co are dissolved in the second phase, the mechanical strength is increased to suppress the micronization.
(quenching conditions)
The material of the roller is preferably an alloy mainly composed of Cu (e.g., Cu, TiCu, ZrCu, BeCu) or an alloy mainly composed of Fe, which is determined by the wettability with the alloy metal solution. In addition, Cr or Ni may be plated on the surface of the roll to a thickness of 1 to 100 μm without using the above-mentioned Cu alloy or Fe alloy.
The thickness of the sample on the roll is preferably set in the range of 10 to 500 μm. The reason for this is that when the thickness of the sample plate is larger than 500. mu.m, the cooling rate becomes slow, and therefore, the first element is hardly dissolved in the intermetallic compound composed of the second element and the third element. The thinner the thickness of the sample plate, the faster the cooling rate. When the thickness of the sample plate is less than 10 μm, the strength of the alloy obtained is insufficient, and the alloy is difficult to handle. The preferable range of the plate thickness is 15 to 300 μm.
Although the roll rotation speed is determined by the material composition, it is generally within the range of 10 to 60m/s, so that the treatment for making the non-equilibrium (non-equilibrium phase of forced solid solution, quasi-crystal phase, etc.) is easy.
The nozzle diameter is preferably in the range of 0.3 to 1 mm. When the nozzle diameter is less than 0.3mm, it is difficult to eject the metal solution from the nozzle. On the other hand, if the nozzle diameter exceeds 1mm, a thick sample is easily obtained, and it is difficult to obtain a sufficient cooling rate.
The gap between the roller and the nozzle is preferably in the range of 0.2 to 10mm, but when the gap exceeds 10mm, if the flow of the metal solution is laminar, the cooling rate can be uniformly increased. However, when the gap is widened, a thick sample is obtained, and the cooling rate is slower as the gap is wider.
In mass production, it is desirable to extract a large amount of heat from the alloy metal solution, and therefore to increase the heat capacity of the roll. The diameter of the roller is preferably at least 300mm phi, more preferably at least 500mm phi. The width of the roller is preferably 50mm or more, more preferably 100mm or more.
The negative electrode materials for nonaqueous electrolyte batteries according to the present invention 13 and 14 will be explained below.
The negative electrode material for a nonaqueous electrolyte battery of the present invention 13 contains a single phase of an element that is alloyed with lithium and a plurality of intermetallic compound phases.
At least two kinds of the intermetallic compound phases (hereinafter, referred to as two or more kinds of intermetallic compound phases X) include an element that is alloyed with lithium (hereinafter, referred to as element P) and an element that is not alloyed with lithium (hereinafter, referred to as element Q), respectively, and combinations of the element P and the element Q are different from each other.
(element monomer phase)
As the element to be alloyed with lithium, Zn, Cd, Al, Ga, In, Si, Ge, Sn, Pb, P, Sb, Bi, S, Se, Te and the like are included. Among them, Al, Sn, Si, Bi and Pb are preferred.
The elemental monomer phase may contain elements that alloy with lithium and other elements that constitute the alloy. In most cases, other elements are solid-dissolved in the metal alloyed with lithium. The content of other elements in the elemental monomer phase is not limited to the extent that it does not affect the battery characteristics, and is generally small, for example, 10 at% or less.
The kind of the elemental monomer phase contained in the anode material 13 may be one kind or two or more kinds.
(multiple intermetallic phases)
First, the two or more intermetallic compound phases X will be described.
The two or more intermetallic compound phases X are each a metal compound of stoichiometric composition. The metal compound of the stoichiometric composition is an intermetallic compound in which the ratio of constituent atoms is expressed as a simple integer ratio (graphic, dictionary for technical metal materials (2 nd edition), written by institute of technical metal materials, published by news agency of the journal industry, release date: 2000, 1/30/2000, p 394).
The element P that is alloyed with lithium contained in each intermetallic compound phase X is the same as the element described in the above-described elemental monomer phase. The kind of the element constituting the element P may be one or two or more. On the other hand, the element Q not alloyed with lithium includes Cr, Mn, Fe, Co, Ni, Cu, and the like. Among them, Fe, Ni, Cu and Cr are preferred. The kind of the element constituting the element Q may be one or two or more.
In the two or more intermetallic compound phases X, all the element types including both the element P and the element Q are different from each other. This structure can increase the number of sites for storing lithium, and thus can alleviate lattice distortion during lithium storage. The combination of the element P and the element Q in the intermetallic compound phase X is different from one another in the kind of the element P constituting each intermetallic compound phase X, the kind of the element Q, or both the kind of the element P and the kind of the element Q. In order to improve the charge-discharge cycle life, it is desirable that the kind of the element constituting the element P is different between the intermetallic compound phases X. By using an intermetallic compound containing an element which is relatively easily alloyed with lithium among the elements P as a lithium storage phase and an intermetallic compound containing an element which is relatively hardly alloyed as a transition point of lithium occlusion and release, lattice deformation accompanying lithium occlusion and release can be effectively alleviated.
The plurality of intermetallic compound phases include other kinds of intermetallic compound phases in addition to the two or more kinds of intermetallic compound phases X. Other types of intermetallic compound phases include intermetallic compound phases having stoichiometric compositions other than the intermetallic compound phase X, and intermetallic compounds having non-stoichiometric compositions. As the intermetallic compound phase having a stoichiometric composition other than the intermetallic compound phase X, two or more kinds of intermetallic compound phases having the same kind of constituent elements but different ratios of constituent elements from each other may be used.
From the viewpoint of capacity, cycle life balance and rate characteristics, the average particle diameter of the plurality of intermetallic compound phases is preferably in the range of 5 to 500 nm. When the average particle diameter exceeds 500nm, a long cycle life cannot be obtained. When the average particle diameter is less than 5nm, excellent ratio characteristics cannot be obtained. The average particle diameter is more preferably 10 to 400 nm.
The average crystal grain size is the longest portion of crystal grains photographed by TEM (transmission electron microscope), and 50 crystal grains adjacent to each other are measured in a photograph (for example, 10 ten thousand times) observed by TEM, and the average value thereof is calculated. The magnification of the TEM photograph may be changed according to the crystal grain size.
The negative electrode material for a nonaqueous electrolyte battery of the present invention 13 contains an unbalanced phase such as an amorphous phase in addition to a plurality of intermetallic compound phases and elemental monomer phases.
The negative electrode material 13 has the following compositions (9) to (13) and (9) '- (13)'.
< composition 1>
XxTlyJz……(9)
Wherein X is at least two elements selected from Al, Si, Mg, Sn, Ge, In, Pb, P and C, T1 is at least one element selected from Fe, Co, Ni, Cr and Mn, J is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, X, y and z satisfy X + y + z 100 atomic%, X is not less than 50 and not more than 90, y is not less than 10 and not more than 33, and z is not less than 0 and not more than 10, respectively.
(element X)
This element X has high affinity with lithium and is a basic element for occluding lithium. By setting the kind of the element constituting the element X to two or more kinds, lattice deformation due to lithium occlusion and release can be alleviated. The reason why the atomic ratio X of the element X is defined within the above range is as follows. When the atomic ratio x is less than 50 atomic%, it is difficult to precipitate a monomer phase of an element that is alloyed with lithium when a negative electrode material is produced by a liquid quenching method such as a single-roll method or an atomization method. On the other hand, if the atomic ratio x is greater than 90 atomic%, the lithium release characteristics of the negative electrode material during charge and discharge are impaired. Since the larger the atomic ratio x is, the more likely the precipitation of the elemental monomer phase is caused, the atomic ratio x is preferably in a range of more than 67 atomic% and less than 90 atomic%, more preferably in a range of 70 to 90 atomic%.
(element Tl)
The reason why the atomic ratio y of the element Tl is defined within the above range is as follows. When the atomic ratio y of the element Tl is less than 10 at%, amorphization and ultrafine crystallization are difficult, and the cycle characteristics are deteriorated. On the other hand, when the atomic ratio y is more than 33 atomic%, the discharge capacity of the battery is remarkably decreased. The atomic ratio y of the element Tl is in the range of 10 to 33 atomic%, which promotes amorphization and ultrafine crystallization and suppresses micronization during occlusion and release of lithium in the negative electrode material. Particularly, when Al, Si, or Mg is contained in the element X, amorphization and ultrafine crystallization can be further promoted. The atomic ratio y of the element Tl is more preferably in the range of 15 to 25 atomic%.
(element J)
Examples of the rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among them, La, Ce, Pr, Nd, Sm are preferred.
By containing the element J in an atomic ratio of 10 at% or less, amorphization and ultrafine crystallization can be promoted. In particular, it is easy to control the average crystal grain size of the microcrystalline phase to 500nm or less. The 4d and 5d transition metals of Zr, Hf, Nb, Ta, Mo and W are added to the element J in a small amount to promote the refinement of crystal grains. The grain refining effect can be improved by increasing Ti and V in the element J. Element J is also useful in releasing occluded lithium. The atomic ratio z is more preferably 8 atomic% or less. However, in the case where the element Tl is of one type, if the amount of the atomic ratio z is less than 0.01 atomic%, the effect of promoting amorphization and ultrafine crystallization may not be obtained, and the effect of suppressing the decrease in charge/discharge capacity may not be obtained, so the lower limit value of the atomic ratio z is preferably 0.01 atomic%.
In the nonaqueous electrolyte secondary battery having the alloy represented by the above formula (9), the alloy composition does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may change the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (9').
< composition 1' >
[XxTlyJz]yLiw……(9’)
Wherein X is at least two or more elements selected from Al, Si, Mg, Sn, Ge, In, Pb, P and C, Tl is at least one element selected from Fe, Co, Ni, Cr and Mn, J is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Mo and W and rare earth elements, X, y, z, V and W respectively satisfy X + y + z-1, X is 0.5-0.9, y is 0.1-0.33, z is 0-0.1, V + W is 100 atomic%, and W is 0 & lt, 50.
The atomic ratios X, y, and z of the element X, the element Tl, and the element J are defined in the above ranges for the same reason as described in the above composition 1.
(Li)
Lithium is an element that takes charge transfer of the nonaqueous electrolyte battery. Therefore, when lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The negative electrode material of composition 1' is easily activated as compared with the negative electrode material of composition 1 containing no lithium, and thus the maximum discharge capacity is obtained earlier in charge and discharge cycles.
However, in the case where the constituent elements do not contain lithium as in the negative electrode material of composition 1, it is necessary to use a lithium-containing compound such as a lithium composite metal oxide for the positive electrode active material. The negative electrode material of composition 1' can use a compound containing no lithium in the constituent elements as a positive electrode active material, which can broaden the kinds of usable positive electrode active materials. However, when the lithium content w exceeds 50 atomic%, amorphization and ultrafine crystallization are difficult. A more preferable range of the lithium content w is 25 atomic% or less.
< composition 2>
AlaTlbJcZd……(10)
Wherein Al is at least one element selected from the group consisting of Si, Mg and AL, Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C and d satisfy a + b + C + d 100 atomic%, a is 50. ltoreq. a.ltoreq.95, b is 5. ltoreq. b.ltoreq.40, C is 0. ltoreq. c.ltoreq.10, and d is 0. ltoreq. d.ltoreq.20, respectively.
(element Al)
The element Al is an essential element for occluding lithium. The reason why the atomic ratio a of the element Al is defined in the above range is as follows. When the atomic ratio a is less than 50 atomic%, it is difficult to precipitate a monomer phase of an element that is alloyed with lithium when a negative electrode material is produced by a liquid quenching method such as a single-roll method or an atomization method. On the other hand, if the atomic ratio a is more than 95 atomic%, lithium release characteristics of the negative electrode material during charge and discharge are impaired. Since the larger the atomic ratio a, the more likely the precipitation of the elemental monomer phase is caused, the atomic ratio a is preferably in a range of more than 67 atomic% and less than 95 atomic%, more preferably in a range of 70 to 95 atomic%.
(element Tl)
The reason why the atomic ratio b of the element Tl is defined within the above range is as follows. When the atomic ratio b of the element Tl is less than 5 at%, amorphization and ultrafine crystallization are difficult, and the cycle characteristics are deteriorated. On the other hand, when the atomic ratio b is more than 40 atomic%, the discharge capacity of the battery is remarkably reduced. The atomic ratio b of the element Tl is in the range of 5 to 40 atomic%, which promotes amorphization and ultrafine crystallization and suppresses micronization during occlusion and release of lithium in the negative electrode material. The atomic ratio b of the element Tl is more preferably in the range of 7 to 35 at%.
(element J)
Examples of the rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among them, La, Ce, Pr, Nd, Sm are preferred.
By containing the element J in an atomic ratio of 10 at% or less, amorphization and ultrafine crystallization can be promoted. In particular, it is easy to control the average crystal grain size of the microcrystalline phase to 500nm or less. The 4d and 5d transition metals of Zr, Hf, Nb, Ta, Mo and W are added to the element J in a small amount to promote the refinement of crystal grains. When the addition amounts of Ti and V in the element J are increased, the effect of refining crystal grains can be improved. Element J is also useful in releasing occluded lithium. The atomic ratio c is more preferably 8 atomic% or less. However, when the element Tl is of one type, if the amount of the atomic ratio c is less than 0.01 atomic%, the effect of promoting amorphization and ultrafine crystallization may not be obtained, and the effect of suppressing the decrease in charge/discharge capacity may not be obtained, so that the lower limit of the atomic ratio c is 0.01 atomic%.
(element Z)
The element Z promotes amorphization and ultrafine crystallization. The content of the element Z is set to 20 atomic% or less in terms of the atomic ratio d, whereby the capacity can be increased or the service life can be prolonged. However, when the atomic ratio d is 20 atomic% or more, the cycle life is reduced. A more preferable range of the atomic ratio d is 15 atomic% or less.
In the nonaqueous electrolyte secondary battery having the alloy represented by the above formula (10), the alloy composition does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may cause a change in the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (10').
< composition 2' >
[AlaTlbJcZd]yLiz……(10’)
Wherein Al is at least one element selected from the group consisting of Si, Mg and Al, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, y and Z each satisfy a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq. b.ltoreq.0.4, C is 0. ltoreq.0.1, d is 0. ltoreq.0.20, y + Z is 100 atomic%, and Z is 0 < 50. ltoreq.50
The reason why the atomic ratios a, b, c, and d of the element Al, the element Tl, the element J, and the element Z are respectively defined within the above ranges is the same as that described in the above composition 2.
(Li)
Lithium is an element that takes charge transfer of the nonaqueous electrolyte battery. Therefore, when lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The negative electrode material of composition 2' is easily activated compared to the negative electrode material of composition 2 not containing lithium, and thus the maximum discharge capacity is obtained earlier in charge and discharge cycles.
However, in the case where the constituent elements do not contain lithium as in the negative electrode material of composition 2, it is necessary to use a lithium-containing compound such as a lithium composite metal oxide for the positive electrode active material. The negative electrode material of composition 2' can use a compound containing no lithium in the constituent elements as a positive electrode active material, which can broaden the kinds of usable positive electrode active materials. However, if the lithium content z exceeds 50 atomic%, amorphization and ultrafine crystallization are difficult. The lithium content z is more preferably 25 atomic% or less.
< composition 3>
Tl100-a-b-c(A21-xJ’x)aBbJc……(11)
Wherein Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, A2 is at least one element selected from the group consisting of Al and Si, J is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, J' is at least one element selected from the group consisting of C, Ge, Pb, P, Sn and Mg, a, b, C and x satisfy, respectively, 10 atom% or more and 85 atom% or less of a, 0 < b > and 35 atom% or less of C, 0 < C > and 10 atom% or less of x, 0 < x > and 0.3, and the content of Sn is less than 20 atom% (including 0 atom%).
(element A2)
The elements Al and Si are basic elements for lithium occlusion. The reason why the atomic ratio a is defined within the above range is as follows. When the atomic ratio a is less than 10 atomic%, the discharge capacity is reduced. On the other hand, when the atomic ratio a is more than 85 atomic%, the cycle life is shortened. The atomic ratio a is more preferably in the range of 15 to 80 atomic%.
(element J')
Replacement of a portion of element A2 with element J' can extend cycle life. When the substitution amount x exceeds 0.3, the discharge capacity decreases or the life prolonging effect cannot be obtained. The content of Sn is set to 20 atomic% or less (including 0 atomic%) when the total of the alloys is 100 atomic%. When the Sn content is 20 atomic% or more, the discharge capacity decreases or the charge-discharge cycle life decreases.
(boron)
When the atomic ratio b exceeds 35 atomic%, the discharge capacity and cycle life are reduced, the discharge capacity reduction rate when the discharge ratio is increased, and the number of charge and discharge cycles required to achieve the maximum discharge capacity is increased. When the atomic ratio b is 35 atomic% or less, the grain refinement (ultrafine crystallization) is promoted, the discharge capacity, cycle life, and rate characteristics are improved, and the number of charge and discharge cycles required to achieve the maximum discharge capacity is reduced. Therefore, in order to promote amorphization, the atomic ratio b is preferably 30 at% or less. The atomic ratio b is more preferably in the range of 0.1 to 28 atomic%. The preferable range is 1 to 25 atomic%.
Boron greatly affects amorphization and grain refinement, and when boron and the element T are contained, amorphization and grain refinement can be greatly promoted.
(element J)
Examples of the rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among them, La, Ce, Pr, Nd, Sm are preferred.
The element J is an element effective for promoting amorphization and grain refinement, and has an effect of suppressing the occurrence of micronization accompanying the release of lithium occlusion. It is also effective in reducing the retention of occluded lithium in the alloy and suppressing the decrease in charge/discharge capacity. However, when the atomic ratio c exceeds 10 atomic%, the discharge capacity is lowered, and therefore the atomic ratio c is preferably 10 atomic% or less. The atomic ratio c is more preferably 8 atomic% or less, still more preferably 5 atomic% or less.
(element Tl)
The element Tl has a function of releasing occluded lithium, and is also an element which needs to be used in combination with B in order to promote amorphization or grain refinement.
In the nonaqueous electrolyte secondary battery having the alloy represented by the above formula (11), the alloy composition does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may cause a change in the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (11').
< composition 3' >
[Tl1-a-b-c(A21-xJ’x)aBbJc]yLiz………………(11’)
Wherein Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr, and Mn, A2 is at least one element selected from the group consisting of Al and Si, J is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, and rare earth elements, J' is at least one element selected from the group consisting of C, Ge, Pb, P, Sn, and Mg, a, b, C, x, y, and z each satisfy 0.1. ltoreq. a.ltoreq.0.85, 0. ltoreq. b.ltoreq.0.35, 0. ltoreq. c.ltoreq.0.1 atomic%, 0. ltoreq. x.ltoreq.0.3, 0. ltoreq. z.50 atomic%, (y + z)% 100 atomic%, and the content of Sn is less than 20 atomic% (including 0 atomic%).
The reason why the atomic ratios a, b, c, and x of the element Tl, the element a2, the element J', boron, and the element J are defined to be within the above ranges is the same as that described in the above composition 3.
(Li)
Lithium is an element that takes charge transfer of the nonaqueous electrolyte battery. Therefore, when lithium is contained as an alloy constituent element, the amount of lithium occluded and released in the negative electrode can be increased, and the battery capacity and the charge-discharge cycle life can be improved. The negative electrode material of composition 3' is easily activated compared to the negative electrode material of composition 3 not containing lithium, and thus the maximum discharge capacity is obtained earlier in charge and discharge cycles. The negative electrode material of composition 3' can use a compound containing no lithium in the constituent elements as a positive electrode active material, thus widening the range of usable positive electrode active materials. However, when the lithium content z exceeds 50 atomic%, amorphization and ultrafine crystallization are difficult. The lithium content z is more preferably 25 atomic% or less.
< composition 4>
(Mg1-xA3x)100-a-b-c-d(RE)aTlbM1cA4d……(12)
Wherein A3 is at least one element selected from the group consisting of Al, Si and Ge, RE is at least one element selected from the group consisting of Y and rare earth elements, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, M1 is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, A4 is at least one element selected from the group consisting of Sn, Pb, Zn, P and C, a, b, C, d and x are each 0 < a < 40 at%, 0 < b < 40 at%, 0 < C < 10 at%, 0 < d < 20 at%, and 0 < x < 0.5.
(magnesium and element A3)
Mg is an essential element for occluding lithium. A part of Mg may be substituted with an element a3 (one or more elements selected from Al, Si, and Ge). However, when the atomic ratio x exceeds 0.5, the cycle life is shortened.
(RE element)
The RE element is an element necessary for obtaining an amorphous phase or an ultrafine crystal phase. The reason why the atomic ratio a is 40 atomic% or less is that if the atomic ratio a is 40 atomic% or more, the capacity decreases. In order to promote amorphization and increase the capacity, the atomic ratio a is preferably in the range of 5 to 40 atomic%, more preferably 7 to 30 atomic%. In order to promote the ultrafine crystallization and increase the capacity, the atomic ratio a should be 40 atomic% or less, preferably 2 to 30 atomic%.
(element Tl)
The combination of the element Tl, Mg and the element RE promotes amorphization and grain refinement. The reason why the atomic ratio b is 40 atomic% or less is as follows. When the atomic ratio b is 40 atomic% or more, the capacity is lowered. In order to promote amorphization and increase the capacity, the atomic ratio b is preferably 5 to 40 atomic%, more preferably 7 to 30 atomic%. In order to promote the ultrafine crystallization and increase the capacity, the atomic ratio b should be 40 atomic% or less, preferably 2 to 30 atomic%.
(element M1)
The element M1 promotes grain refinement and amorphization. It is also effective in reducing the retention of occluded lithium in the alloy and suppressing the decrease in charge/discharge capacity. The atomic ratio c is more preferably 8 atomic% or less.
(element A4)
The content of the element A4 is set to 20 atomic% or less in terms of atomic ratio, whereby the capacity can be improved or the service life can be prolonged. However, when the atomic ratio d is 20 atomic% or more, the cycle life is reduced.
In the nonaqueous electrolyte secondary battery having the alloy represented by the above formula (12), the alloy composition does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may cause a change in the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (12').
< composition 4' >
[(Mg1-xA3x)1-a-b-c-d(RE)aTlbM1cA4d]yLiz……(12’)
Wherein A3 is at least one element selected from the group consisting of Al, Si and Ge, RE is at least one element selected from the group consisting of Y and rare earth elements, Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, M1 is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, A4 is at least one element selected from the group consisting of Sn, Pb, Zn, P and C, a, b, C, d, x, Y and z each satisfy 0 < a < 0.4, 0 < b < 0.4, 0 < C < 0.1, 0 < d < 0.2, 0 < x < 0.5, 0 < a < 50 at%, and (Y + z) ═ 100 at%.
The reason why the atomic ratios a, b, c, d, and x of Mg, the element A3, the element RE, the element Tl, the element M1, and the element A4 are defined to be within the above ranges is the same as that described in the above composition 4.
< composition 5>
(Al1-xA5x)aTlbJcZd……(13)
Wherein A5 is at least one element selected from the group consisting of Si and Mg, Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atomic%, a is 50. ltoreq. a.ltoreq.95, b is 5. ltoreq.40, C is 0. ltoreq. 10, d is 0. ltoreq. 20, and x is 0. ltoreq. x.0.9, respectively.
(aluminum and element A5)
When Si is used as the element A5, the atomic ratio x is preferably in the range of 0 < x.ltoreq.0.75. When the atomic ratio x of Si exceeds 0.75, the cycle life of the secondary battery decreases. The atomic ratio x is more preferably in the range of 0.2 to 0.6.
When Si is used as the element A5, the total atomic ratio a of Al and Si is preferably in the range of 50 to 95 atomic%. When the total atomic ratio is 50 atomic% or less, the lithium storage capacity of the negative electrode material decreases, and the discharge capacity, cycle life, and rate characteristics of the secondary battery are difficult to improve. On the other hand, when the total atomic ratio is 95 atomic% or more, the negative electrode material hardly causes a lithium release reaction. The total atomic ratio is more than 67 atomic% and less than 90 atomic%, preferably 70 to 90 atomic%.
When Mg or Mg and Si are used as A5, the atomic ratio x is preferably in the range of 0 < x.ltoreq.0.9. If the atomic ratio x of the element a5 exceeds 0.9, the cycle life and rate characteristics of the secondary battery may be degraded. A more preferable range of the atomic ratio x is 0.3. ltoreq. x.ltoreq.0.8.
When Mg or Mg and Si are used as A5, the total atomic ratio a of Al and the element A5 is preferably in the range of 50 to 95 atomic%. When the total atomic ratio is 50 atomic% or less, the lithium storage capacity of the negative electrode material decreases, and the discharge capacity, cycle life, and rate characteristics of the secondary battery are difficult to improve. On the other hand, when the total atomic ratio is 95 atomic% or more, the negative electrode material hardly causes a lithium release reaction. The total atomic ratio is more than 67 atomic% and less than 90 atomic%, preferably 70 to 85 atomic%.
(element Tl)
The reason why the atomic ratio b of the element Tl is defined in the above range is as follows. When the atomic ratio b of the element Tl is less than 5 at%, amorphization and ultrafine crystallization are difficult. On the other hand, when the atomic ratio b of the element Tl exceeds 40 at%, the discharge capacity of the secondary battery is significantly reduced. The atomic ratio b of the element Tl is set to 10 to 33 atomic%, which promotes amorphization and ultrafine crystallization and suppresses micronization during occlusion and release of lithium in the negative electrode material. The atomic ratio b of the element Tl is more preferably in the range of 15 to 30 at%.
(element J)
Examples of the rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among them, La, Ce, Pr, Nd, Sm are preferred.
By containing the element J in an atomic ratio of 10 at% or less, amorphization and ultrafine crystallization can be promoted. The retention of the occluded Li in the alloy is reduced, and the decrease of the charge/discharge capacity is suppressed. The atomic ratio c is more preferably 8 atomic% or less. In the case where the type of the element Tl is one, if the amount of the atomic ratio c is less than 0.01 atomic%, the effect of promoting amorphization and ultrafine crystallization and the effect of suppressing the decrease in charge/discharge capacity may not be obtained, and therefore the lower limit of the atomic ratio c is preferably 0.01 atomic%.
(element Z)
The element Z promotes amorphization and ultrafine crystallization. The content of the element Z is set to 20 atomic% or less in terms of the atomic ratio d, whereby the capacity can be increased or the service life can be prolonged. However, when the atomic ratio d is 20 atomic% or more, the cycle life is shortened. A more preferable range of the atomic ratio d is 15 atomic% or less.
In the nonaqueous electrolyte secondary battery having the alloy represented by the above formula (13), the alloy composition does not change before charge and discharge are performed, and Li remaining as an irreversible capacity may change the alloy composition when charge and discharge are performed. The alloy composition after the change is represented by the following general formula (13').
< composition 5' >
[(Al1-xA5x)aTlbJcZd]yLiz……(13’)
Wherein A5 is at least one element selected from the group consisting of Si and Mg, Tl is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and Z are each a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.9, y + Z100 atomic%, 0. ltoreq. z.50 atomic%.
The reason why the atomic ratios a, b, c, d, and x of the element A5, the element Tl, the element J, and the element Z are defined to be within the above ranges is the same as that described in the above composition 5. The reason why the atomic ratio z of Li is defined within the above range is the same as that described in the above composition 5.
The negative electrode material for a nonaqueous electrolyte battery having a composition represented by the formula (9), (10), (11), (12) or (13) has no lithium contained in the constituent elements of the alloy, and therefore, the element treatment at the time of synthesizing the negative electrode material is simple. When the liquid quenching method is adopted to synthesize the cathode material, the danger of ignition and the like is avoided, and the large-scale production is easy. In the alloy system not containing a lithium alloy, the activation energy of an amorphous phase, a metastable phase, and a stable phase is high, or the grain growth of a microcrystalline phase is slow, and therefore, the crystal structure itself is stable, which is advantageous for the cycle life of the electrode characteristics. In addition, the manufacturing yield of the negative electrode material can be improved with little influence of the fluctuation of the heat treatment conditions.
By using the negative electrode material for a nonaqueous electrolyte battery of the present invention 13, a nonaqueous electrolyte secondary battery can be obtained which does not suffer from deterioration in cycle life of discharge capacity and charge capacity and can improve rate characteristics and satisfy requirements for discharge capacity, charge-discharge cycle life and rate characteristics at the same time. The number of charge and discharge times required for the secondary battery to reach the maximum discharge capacity is reduced.
That is, the monomer phase of the element alloyed with lithium improves the lithium occlusion/release rate and at the same time, the capacity can be increased. On the other hand, the intermetallic compound phase is also effective in improving the lithium occlusion/release rate. In a plurality of intermetallic compound phases including two or more intermetallic compound phases X, since the lithium occlusion easiness of the intermetallic compound phases is significantly different, a phase which is relatively likely to cause a lithium occlusion reaction is used as a lithium storage phase, and a phase which is relatively less likely to cause a lithium occlusion reaction is used as a transition point of lithium occlusion/release, thereby alleviating lattice deformation at the time of lithium occlusion/release. As a result, the rate characteristics are improved without affecting the discharge capacity and the charge-discharge cycle life, and the number of charge-discharge cycles required to achieve the maximum discharge capacity is reduced.
The composition of the negative electrode material for nonaqueous electrolyte batteries of the present invention 13 is represented by the general formulae (9) to (13) and (9 ') to (13'), and the discharge capacity, charge-discharge cycle life and rate characteristics of nonaqueous electrolyte secondary batteries can be improved. Among them, the compositions represented by the general formulae (13) and (13') are most preferable because the charge-discharge cycle life can be further improved.
< negative electrode Material for nonaqueous electrolyte Battery 14>
The negative electrode material for a nonaqueous electrolyte battery of the present invention 14 contains a monomer phase, an intermetallic compound phase, and a nonequilibrium phase of an element that alloys with lithium.
(element monomer phase)
The elemental monomer phase is the same as described above for the negative electrode material 13 for a nonaqueous electrolyte battery.
(intermetallic compound phase)
The kind of the intermetallic compound phase included in the anode material 14 may be one kind or two or more kinds.
The intermetallic compound contains an element that is alloyed with lithium and an element that is not alloyed with lithium. Specific examples of the element that alloys with lithium and the element that does not alloy with lithium are the same as those described for the negative electrode material 13. From the viewpoint of improving the charge-discharge cycle life, two or more types of elements that can be alloyed with lithium are desired.
The intermetallic phase has a stoichiometric composition. The intermetallic compound phase of the stoichiometric composition includes the intermetallic compound phase (two or more intermetallic compound phases X) described in the above-described negative electrode material 13, two or more intermetallic compound phases having the same kind of the constituent elements and different composition ratios of the constituent elements, a plurality of intermetallic compounds having no specific relationship between the compositions, and the like.
For the same reason as that for the negative electrode material 13, the average particle diameter of the intermetallic compound phase is in the range of 5 to 500 nm. The average particle diameter is more preferably 10 to 400 nm.
(nonequilibrium phase)
As the non-equilibrium phase, an amorphous phase, a quasi-crystalline phase, an intermetallic compound of non-stoichiometric composition, and the like are included. The non-equilibrium phase may be a single phase or a composite phase.
The non-equilibrium phase was confirmed by the following method.
First, the negative electrode material was subjected to thermal analysis and measurement to confirm whether or not an exothermic peak occurred. When an exothermic peak (for example, an exothermic peak at 200 to 700 ℃ at a rate of 10 ℃/min) occurs, the negative electrode material contains an unbalanced phase. Then, the microstructure of the nonequilibrium phase was observed by X-ray diffraction or transmission electron microscope. In the X-ray diffraction of the negative electrode material containing the non-equilibrium phase, the diffraction data by the known intermetallic compound is not detected, and when the heat treatment is performed at a temperature at which the exothermic peak appears and then the X-ray diffraction measurement is performed again, the diffraction peak by the known intermetallic compound can be confirmed.
The composition of the negative electrode material of the invention 14 may, for example, be represented by the general formulae (9) to (13'). Among them, the compositions represented by the general formulae (13) and (13') can further improve the charge-discharge cycle life.
The use of the negative electrode material for a nonaqueous electrolyte battery of the present invention 14 improves the rate characteristics without affecting the discharge capacity and the charge/discharge cycle life, and therefore, a nonaqueous electrolyte secondary battery excellent in the discharge capacity, the charge/discharge cycle life and the rate characteristics can be provided, and the number of charge/discharge cycles required for the secondary battery to reach the maximum discharge capacity can be reduced.
That is, the monomer phase and the intermetallic compound phase of the element alloyed with lithium can improve the capacity while improving the rate of occlusion and release of lithium. On the other hand, since the nonequilibrium phase has a crystal structure deformed in advance, deformation at the time of lithium insertion can be alleviated, and micronization of the negative electrode material can be suppressed. As a result, the rate characteristics can be improved and the number of charge and discharge cycles required to achieve the maximum discharge capacity can be reduced without impairing the discharge capacity and the charge and discharge cycle life.
The anode materials of the present invention 13 and 14 can be produced by a liquid quenching method, a mechanical alloying method, or a mechanical milling method.
(liquid quenching method)
The liquid quenching method is a method in which an alloy metal solution prepared to have a predetermined composition is discharged from a small nozzle onto a cooling body (e.g., a roll) rotating at high speed to be quenched. The sample obtained by the liquid quenching method may have a long thin band shape, a thin sheet shape, or the like. When the composition of the sample is changed, the melting point and the amorphous phase formation energy or the microcrystalline phase formation energy are different from each other, and therefore the shape of the sample tends to change depending on the composition. In another aspect. The cooling rate mainly dominates the thickness of the quenched sample, and the thickness of the sample is adjusted depending on the material of the roll, the number of revolutions of the roll, and the diameter of the nozzle hole.
The metal solution may have any one of the compositions represented by the above formulae (9) to (13) and (9 ') to (13').
The material of the roller is determined to be optimum depending on the wettability with the alloy metal solution, and is preferably an alloy mainly containing Cu (e.g., Cu, TiCu, ZrCu, BeCu).
The roll rotation speed is determined depending on the composition, and the microcrystals can be obtained at a roll rotation speed of about 10m/s or more. When the roller rotation speed is less than 20m/s, a mixed phase of a microcrystalline phase and an amorphous phase is easily obtained. On the other hand, when the roll rotation speed is more than 60m/s, the alloy metal solution is hard to be held on the cooling roll rotating at a high speed, and therefore, the cooling speed is lowered, and the fine crystal phase is liable to be precipitated. Therefore, although the roll rotation speed can be determined according to the composition, it is generally in the range of about 20 to 60m/s, and the amorphization is easily achieved.
The nozzle diameter is preferably in the range of 0.3 to 2 mm. When the nozzle diameter is less than 0.3mm, it is difficult to eject the metal solution from the nozzle. On the other hand, if the nozzle diameter exceeds 2mm, a thick sample is easily obtained, and it is difficult to obtain a sufficient cooling rate.
The gap between the roller and the nozzle is preferably in the range of 0.2 to 10mm, but when the gap exceeds 10mm, if the flow of the metal solution is laminar, the cooling rate can be uniformly increased. However, since a thick sample is obtained when the gap is wide, the cooling rate is slow as the gap is wide.
In mass production, it is desirable to increase the heat capacity of the roll because a large amount of heat needs to be extracted from the alloy metal solution. For these reasons, it is desirable to increase the roller diameter and widen the roller width. Specifically, the roll diameter is preferably 300mm φ or more, and more preferably 500mm φ or more. The width of the roller is preferably 50mm or more, more preferably 100mm or more.
(mechanical alloying, mechanical grinding)
Mechanical alloying and mechanical grinding are methods in which powder prepared to a predetermined composition is charged into a pot (pot) in an inert atmosphere, the powder is held by rolling balls in the pot by rotation, and alloying is performed by energy at that time.
Alloys produced by liquid quenching, mechanical alloying or mechanical milling processes can be subjected to a heat treatment for embrittlement. From the viewpoint of suppressing the progress of crystallization, in the case where the exothermic peak is one, the heat treatment temperature is in the range from a temperature lower by 50 ℃ than the temperature rise degree (crystallization temperature) thereof to a temperature higher by 50 ℃ than the temperature. When a plurality of exothermic peaks are present, it is preferable that the temperature range is not less than 50 ℃ lower than the temperature of rise of the lowest exothermic peak and not more than the temperature of the exothermic peak located on the highest temperature side.
In addition to the liquid quenching method, the mechanical alloying method, and the mechanical milling method, a gas atomization method, a rotary disk method, a rotary electrode method, and the like can be used to obtain a powdery sample. Since a spherical sample can be obtained by selecting a certain condition and using these methods, the negative electrode material can be packed most densely in the negative electrode, and the capacity of the battery can be increased.
A nonaqueous electrolyte battery includes a negative electrode including at least one of negative electrode materials 1 to 14, a positive electrode, and a nonaqueous electrolyte layer disposed between the positive electrode and the negative electrode.
1) Negative electrode
The negative electrode comprises a current collector and a negative electrode layer formed on one or both surfaces of the current collector and containing at least one of the negative electrode materials 1 to 14.
The negative electrode is produced by kneading a powder of a negative electrode material and a binder in the presence of an organic solvent, applying the resultant suspension to a current collector, drying the resultant suspension, and compacting the dried resultant suspension.
When obtaining the powders of the negative electrode materials 1, 2, 5, 6, 13 and 14, the powders are embrittled by performing a heat treatment at a temperature of not higher than the crystallization temperature for 0.1 to 24 hours before being pulverized. As the pulverization method, a pin mill, a jet mill, a hammer mill and a ball mill can be used.
On the other hand, in the case where the samples temporarily amorphized are synthesized from the negative electrode materials 3, 4, 7, 8, 13 and 14 by heat-treating the samples at a temperature higher than the crystallization temperature thereof for 0.1 to 24 hours, it is desirable that the pulverization treatment be performed after the heat treatment. The production cost of the negative electrode material can be reduced by heat-treating the amorphized sample at a temperature higher than the crystallization temperature of the sample to produce the negative electrode material. The crystallization temperature of the amorphized sample can be determined from the exothermic peak of Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃ per minute. Specifically, when one exothermic peak is detected, the transition temperature at which the amorphous phase in the sample shifts to the equilibrium phase is measured from the exothermic peak, and the obtained transition temperature is taken as the crystallization temperature. On the other hand, when a plurality of exothermic peaks are detected, the transition temperature of the sample is measured from the exothermic peak detected on the lowest temperature side, and the obtained transition temperature is defined as the crystallization temperature. The measurement of the transition temperature from the heat emission peak can be carried out by the method described in the differential scanning calorimetry of example 52 described later. The sample can be synthesized by precipitating a microcrystalline phase by a rapid cooling method, and in this case, the presence or absence of heat treatment before pulverization may be acceptable.
The sample is pulverized into particles having an average particle diameter of 5 to 80 μm by a pulverizing device such as a jet mill, a pin mill, a hammer mill, etc. The average particle diameter can be measured by the micro-orbital method using a laser. The sample used in the present invention has a shape close to a flat plate, and in the measurement by the micro-orbital method, the sample having a shape close to a flat plate is assumed to be spherical, and data processing is performed to determine the average particle diameter.
As the binder, Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), or the like can be used.
The mixing ratio of the negative electrode material and the binder is preferably 90 to 98 wt% of the negative electrode material and 1 to 10 wt% of the binder.
The current collector is not particularly limited as long as it is made of a conductive material. Foils, screens, perforated metals, lath metals, etc., of copper, stainless steel or nickel may be used.
2) Positive electrode
The positive electrode includes a current collector and a positive electrode active material layer containing a positive electrode active material formed on one or both surfaces of the current collector.
The positive electrode is produced by suspending a positive electrode active material, a conductive agent, and a binder in a solvent as appropriate, applying the resultant suspension to the surface of a current collector, and then drying and compacting the coating.
The positive electrode active material is not particularly limited as long as it can absorb an alkali metal such as lithium during discharge of the battery and can release the alkali metal during charge. As the positive electrode active material, various oxides and sulfides are included, for example, manganese dioxide (MnO)2) Lithium manganese complex oxide (e.g., LiMn)2O4、LiMnO2) Lithium nickel composite oxide (e.g., LiNiO)2) Lithium cobalt composite oxide (e.g., LiCoO)2) Lithium nickel cobalt complex oxide (e.g., LiNi)1-xCoxO2) Lithium manganese cobalt composite oxides (e.g., LiMn)xCo1-xO2) Vanadium oxide (V)2O5) And the like. In addition, the conductive polymer material, disulfide polymer material and other organic materials. Preferred positive electrode active materials include lithium manganese composite oxides (e.g., LiMn) having high cell voltages2O4) Lithium nickel composite oxide (e.g., LiNiO)2) Lithium cobalt composite oxide (e.g., LiCoO)2) Lithium nickel cobalt complex oxide (e.g., LiNi)0.8Co0.2O2) Lithium manganese cobalt composite oxides (e.g., LiMn)xCo1-xO2) And the like.
As the binder, Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluororubber, or the like is included.
As the conductive agent, acetylene black, carbon black, graphite, and the like are included.
The mixing ratio of the positive electrode active substance, the adhesive and the conductive agent is preferably 80-95 wt% of the positive electrode active substance, 3-20 wt% of the conductive agent and 2-7 wt% of the adhesive.
The current collector is not particularly limited as long as it is made of a conductive material. However, as the positive electrode current collector, it is preferable to use a material that is difficult to oxidize during battery reaction, for example, aluminum, stainless steel, titanium, or the like.
3) Non-aqueous electrolyte layer
The nonaqueous electrolyte layer may provide ion conductivity between the positive electrode and the negative electrode.
Examples of the nonaqueous electrolyte layer include a separator for retaining a nonaqueous electrolyte solution, a gel-like nonaqueous electrolyte layer, a separator for retaining a gel-like nonaqueous electrolyte solution, a solid polymer electrolyte layer, and an inorganic solid electrolyte layer.
As the separator, a porous material can be used. The material of the separator includes a nonwoven fabric made of synthetic resin, a polyethylene porous film, a polypropylene porous film, and the like.
The nonaqueous electrolytic solution can be prepared by dissolving an electrolyte in a nonaqueous solvent.
As the nonaqueous solvent, a cyclic carbonate such as Ethylene Carbonate (EC) or Propylene Carbonate (PC) may be used, and a nonaqueous solvent mainly composed of a mixed solvent of the cyclic carbonate and a nonaqueous solvent having a lower viscosity than the cyclic carbonate may be used. Examples of the nonaqueous solvent having a low viscosity include chain carbonates (e.g., dimethyl carbonate, methylethyl carbonate, diethyl carbonate, etc.), γ -butyrolactone, acetonitrile, methyl propionate, ethyl propionate, cyclic ethers (e.g., tetrahydrofuran, 2-methyltetrahydrofuran, etc.), and chain ethers (e.g., dimethoxyethane, diethoxyethane, etc.).
As the electrolyte, a lithium salt is used. Specifically, lithium hexafluorophosphate (LiPF) is included6) Lithium borofluoride (LiBF)4) Lithium hexafluoroarsenate (LiAsF)6) Lithium perchlorate (LiClO)4) Lithium trifluoromethanesulfonate (LiCF)3SO3) And the like. Among them, preferred is lithium hexafluorophosphate (LiPF)6) Lithium borofluoride (LiBF)4)。
The total amount of the electrolyte dissolved in the nonaqueous solvent is preferably 0.5 to 2 mol/L.
The gel-like nonaqueous electrolyte can be obtained by combining a nonaqueous electrolyte and a polymer material. The polymer material includes a polymer of a monomer such as polyacrylonitrile, polyacrylate, polyvinylidene fluoride (PVdF), or polyethylene oxide (PECO), or a copolymer with another monomer.
The solid polyelectrolyte layer can be obtained by dissolving an electrolyte in a polymer material and solidifying the solution. The polymer material includes a polymer of a monomer such as polyacrylonitrile, polyvinylidene fluoride (PVdF), or polyethylene oxide (PEO), or a copolymer with another monomer.
As the inorganic solid electrolyte, a lithium-containing ceramic material is included. Specific examples Li3N、Li3PO4-Li2S-SiS2、LiI-Li2S-SiS2Glass, and the like.
A thin nonaqueous electrolyte secondary battery as an example of the nonaqueous electrolyte battery of the present invention will be described in detail with reference to fig. 1 and 2.
Fig. 1 is a cross-sectional view of a thin nonaqueous electrolyte secondary battery according to an example of the nonaqueous electrolyte battery of the present invention, and fig. 2 is an enlarged cross-sectional view showing a portion a of fig. 1.
As shown in fig. 1, an electrode group 2 is built in an outer jacket material 1 made of a laminated film. The electrode group 2 has a structure in which a laminate of a positive electrode, a separator, and a negative electrode is wound in a flat shape. As shown in fig. 2 (from the lower side of the figure), the above laminate sequentially laminates a separator 3, a positive electrode 6 having a positive electrode layer 4, a positive electrode collector 5, and a positive electrode layer 4, a separator 3, a negative electrode 9 having a negative electrode layer 7, a negative electrode collector 8, and a negative electrode layer 7, a separator 3, a positive electrode 6 having a positive electrode layer 4, a positive electrode collector 5, and a positive electrode layer 4, a separator 3, and a negative electrode 9 having a negative electrode layer 7 and a negative electrode collector 8. The negative electrode current collector 8 is placed on the outermost layer of the electrode group 2. A strip-shaped positive electrode lead 10 has one end connected to the positive electrode current collector 5 of the electrode group 2 and the other end extending from the outer jacket material 1. On the other hand, the band-shaped negative electrode lead 11 has one end connected to the negative electrode current collector 8 of the electrode group 2 and the other end extending from the outer jacket material 1.
While fig. 1 and 2 show an example in which an electrode group formed by winding a positive electrode, a nonaqueous electrolyte layer, and a negative electrode in a flat shape is used, the present invention is also applicable to an electrode group formed by a laminate of a positive electrode, a nonaqueous electrolyte layer, and a negative electrode, and an electrode group having a structure in which the laminate of a positive electrode, a nonaqueous electrolyte layer, and a negative electrode is bent 1 or more times.
Embodiments of the present invention are described in detail below with reference to the accompanying drawings.
(examples 1 to 10)
< preparation of negative electrode >
The elements in the ratios shown in table 1 were heated and melted, and then a ribbon-like alloy was obtained by a single-roll method in an inert atmosphere. Specifically, a metal solution was injected from a nozzle hole of 0.6mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and the molten metal was quenched to obtain a ribbon-like alloy. The same alloy can be obtained by either allowing the atmosphere to be atmospheric gas during quenching or allowing an inert gas to flow toward the tip of the nozzle.
The crystallinity of the obtained alloys of examples 1 to 10 was measured by an X-ray diffraction method, and it was confirmed that no peak based on the crystal phase was observed. FIG. 3 shows an X-ray diffraction pattern (X-ray; CuK. alpha.) of the alloy of example 1.
The thin strip alloys of examples 1 to 3 and 7 to 8 were cut and pulverized by a jet mill to obtain alloy powders having an average particle size of 10 μm. The ribbon-like alloys of examples 4 to 6 and 9 to 10 were cut, then subjected to a heat treatment at 250 ℃ which is a temperature not higher than the crystallization temperature for 3 hours to maintain the amorphous phase and embrittle the alloy as it is, and further pulverized by a jet mill to obtain alloy powder having an average particle size of 10 μm.
94 wt% of the alloy powder, 3 wt% of graphite powder as a conductive material, 2 wt% of styrene butadiene rubber as a binder, and 1 wt% of carboxymethyl cellulose as an organic solvent were mixed and dispersed in water to prepare a suspension. This suspension was applied to a copper foil having a thickness of 18 μm as a current collector, dried, and then compacted to produce a negative electrode.
< preparation of Positive electrode >
A slurry was prepared by mixing 91 wt% of lithium cobalt oxide powder, 6 wt% of graphite powder, and 3 wt% of polyvinylidene fluoride, and dispersing them in N-methyl-2-pyrrolidone. The slurry was applied to an aluminum foil as a current collector, dried, and then compacted to produce a positive electrode.
< preparation of lithium ion Secondary Battery >
A separator comprising a polyethylene porous film was prepared. The separator was inserted between the positive electrode and the negative electrode, and the electrode group was wound in a spiral shape. Lithium hexafluorophosphate as an electrolyte was dissolved at 1mol/L in a mixed solvent of ethylene carbonate and methyl ethyl carbonate (volume ratio: 1: 2) to prepare a nonaqueous electrolytic solution.
The electrode group was placed in a cylindrical container made of stainless steel and having a bottom, and then a nonaqueous electrolyte solution was injected into the container to seal the container, thereby assembling a cylindrical lithium ion secondary battery.
(examples 11 to 12)
Alloys having the compositions shown in table 1 below were produced by a mechanical alloying method. The crystallinity of the obtained alloy was measured by X-ray diffraction. It was confirmed that no peak based on the crystal phase was observed. Further, the resultant was pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 13 to 14)
After heating and melting the elements in the ratios shown in Table 2, an alloy metal solution was injected by a single-roll method from a nozzle hole of 0.8 mm. phi. into a cooling roll made of BeCu alloy rotating at a speed of 45m/s in an inert atmosphere, and quenched to obtain a thin ribbon-like or flake-like alloy. The crystallinity of the obtained alloy was measured by an X-ray diffraction method, and it was confirmed that no peak based on the crystal phase was observed. The same alloy can be obtained by either allowing the atmosphere to be atmospheric gas during quenching or allowing an inert gas to flow toward the tip of the nozzle.
The alloy was heat-treated at 300 ℃ or higher in an inert atmosphere for 1 hour, cut, and pulverized with a jet mill to obtain an alloy powder having an average particle size of 10 μm.
1) Determination of the proportion of microcrystalline phases in the alloy
The heat release at a temperature increase rate of 10 ℃/min was measured by Differential Scanning Calorimetry (DSC) on an alloy having the same composition as in examples 13 to 14 and consisting of an amorphous phase, to obtain a reference heat release. The heat release amount was measured at a temperature increase rate of 10 ℃ per minute for the alloys of examples 13 to 14 in which the ratio of the microcrystalline phase was unknown by Differential Scanning Calorimetry (DSC). The ratio of the microcrystalline phase was measured by comparing the heat release amount with the reference heat release amount, and the results are shown in table 2 below.
2) Measurement of average Crystal particle diameter of microcrystalline phase
Transmission Electron Microscope (TEM) photographs were taken, and for 50 crystal grains adjacent to each other, the maximum diameter of each crystal grain was measured, and the average value thereof was taken as the average crystal grain diameter, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 15 to 16)
The elements in the ratios shown in table 2 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. Specifically, an alloy metal solution was injected from a nozzle hole of 0.8mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 25m/s in an inert atmosphere, and quenched to obtain a flake alloy. The alloy was cut and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 2 below. FIG. 4 shows an X-ray diffraction pattern (X-ray; CuK. alpha.) of the alloy of example 15. As can be seen from fig. 4, the alloy of example 15 exhibited peaks based on the crystal phase in the X-ray diffraction pattern. In fig. 4, the peak P1 near 40 ° at 2 θ is from the Al monomer phase, and the peak P2 near 30 ° and the peak P3 near 45 ° at 2 θ are from the microcrystalline phase. As is clear from the X-ray diffraction pattern of fig. 4, the crystal structure of the microcrystalline phase contained in the alloy of example 15 is a fluorite structure having a lattice constant of 5.52 a.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 17 to 18)
The elements in the ratios shown in table 2 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. Specifically, an alloy metal solution was injected from a nozzle hole of 0.8mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 25m/s in an inert atmosphere, and quenched to obtain a flake alloy. The alloy was heat-treated at 300 ℃ for 1 hour to adjust the microstructure. Then, the alloy was cut and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
Examples 19 to 20
The elements in the ratios shown in table 2 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. Specifically, an alloy metal solution was injected from a nozzle hole of 0.6mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and quenched to obtain a thin ribbon-like or flake-like alloy. The crystallinity of the obtained alloy was measured by an X-ray diffraction method, and peaks based on crystal phases which were not observed were confirmed. The same alloy can be obtained by either allowing the atmosphere to be atmospheric gas during quenching or allowing an inert gas to flow toward the tip of the nozzle.
The alloy was heat-treated at 300 ℃ in an inert atmosphere for 1 hour, cut, and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
1) Determination of the proportion of microcrystalline phases in the alloy
The ratio of the microcrystalline phases was evaluated by comparing the intensity of the same diffraction peak of the alloys of examples 19 to 20, in which the ratio of the microcrystalline phases was unknown, with the reference intensity, based on the diffraction intensity of the strongest peak in the X-ray diffraction pattern of the alloys having the same compositions as examples 19 to 20 and the microcrystalline phase ratio of 100%, and the results are shown in table 2 below.
2) Measurement of average Crystal particle diameter of microcrystalline phase
The average crystal grain size of the microcrystalline phase was measured in the same manner as in example 13, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
Examples 21 to 22
The elements in the ratios shown in table 2 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. Specifically, an alloy metal solution was injected from a nozzle hole of 0.7mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 20m/s in an inert atmosphere, and quenched to obtain a flake alloy. The crystallinity of the obtained alloy was measured by X-ray diffraction method, and a peak based on the crystal phase was observed.
The alloy was subjected to heat treatment at 300 ℃ for 1 hour to embrittle the alloy, and then cut into pieces, which were pulverized by a jet mill to obtain alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 23 to 24)
Alloys having the compositions shown in Table 2 below were produced by a mechanical alloying method. Further, the resultant was pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 19, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 25 to 27)
The elements in the ratios shown in table 2 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. Specifically, an alloy metal solution was injected from a nozzle hole of 0.5mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and quenched to obtain a thin ribbon-like or flake-like alloy. The crystallinity of the obtained alloy was measured by X-ray diffraction, and it was confirmed that no peak based on the crystal phase was observed.
The alloy was heat-treated at 300 ℃ in an inert atmosphere for 1 hour, cut, and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
Comparative example 1
Mesophase pitch-based carbon fibers (average fiber diameter of 10 μm, average fiber length of 25 μm, and surface spacing d) heat-treated at 3250 ℃ were used in place of the alloy powder0020.3355nm, a specific surface area of 3m by the BET method2A lithium ion secondary battery was produced in the same manner as in example 1 except for the carbon powder in the above-mentioned amount.
Comparative example 2
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that Al powder having an average particle size of 10 μm was used instead of the alloy powder.
Comparative example 3
Sn is prepared by mechanical alloying method for 100 hours30Co70And (3) alloying. The obtained alloy was confirmed to be amorphous by X-ray diffraction. Except for using this alloy, a lithium ion secondary battery was fabricated in the same manner as described in example 1 above.
Comparative examples 4 to 6
As a negative electrode material, Si is prepared by a single-roll method33Ni67Alloy, (Al)0.1Si0.9)33Ni67Alloy, Cu50Ni25Sn25And (3) alloying. The material of the roller is BeCu alloy, and the rotating speed of the roller is 25 m/s. The microcrystallization of the obtained alloy was confirmed by X-ray diffraction. The average particle size was calculated by the Scherrer formula, and the results are shown in table 3 below. Except for using this alloy, a lithium ion secondary battery was fabricated in the same manner as described in example 1 above.
Comparative example 7
As a negative electrode material, Fe is prepared by grinding25Si75And (3) alloying. The average particle size was calculated by the Scherrer formula, and the average crystal particle size was 300 nm. Except for using this alloy, a lithium ion secondary battery was fabricated in the same manner as described in example 1 above.
Comparative examples 8 to 10
After heating and melting the elements in the ratios shown in Table 3, an alloy metal solution was injected from a nozzle hole of 0.7 mm. phi. into a cooling roll rotating at a speed of 30m/s (the roll material was BeCu alloy) in an inert atmosphere by a single roll method, and quenched to obtain a thin ribbon-like or flake-like alloy. The crystallinity of the obtained alloy was measured by X-ray diffraction, and it was confirmed that no peak based on the crystal phase was observed.
The alloy was heat-treated at 300 ℃ in an inert atmosphere for 1 hour, cut, and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 2 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
The secondary batteries of examples 1 to 27 and comparative examples 1 to 10 were subjected to the following charge-discharge cycle test. That is, after charging was carried out at 20 ℃ for 2 hours with a charging current of 1.5A to 4.2V, the discharge capacity was measured from 1.5V to 2.7V, and the discharge capacity ratio and the capacity retention rate at 300 cycles were measured, and the results are shown in tables 1 to 3 below. The discharge capacity ratio was represented by a ratio at which the discharge capacity of comparative example 1 was 1, and the capacity retention rate was represented by a discharge capacity at 300 cycles at which the maximum discharge capacity was 100%.
After charging at a constant current and a constant voltage of 4.2V at a rate of 1C for 1 hour at 20 ℃, the discharge capacity at 3.0V was measured at a rate of 0.1 to obtain a discharge capacity of 0.1C. After charging under the same conditions, the discharge capacity at 1C rate until 3.0V was measured, and the discharge capacity at 1C was obtained. The discharge capacity at 1C was expressed by taking the discharge capacity at 0.1C as 100%, and the results are shown in tables 1 to 3 below as rate characteristics.
The results of measuring the number of cycles required to achieve the maximum discharge capacity in the charge-discharge cycles at 1C for the secondary batteries of examples 1 to 27 and comparative examples 1 to 10 are shown in tables 1 to 3 below.
TABLE 1
Negative electrode material Characteristics of battery
Alloy composition Metallic structure Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge
Example 1 (Al0.75Si0.25)80Ni14Co4C2 Amorphous form 1.5 85 97 7
Example 2 (Al0.95Si0.05)84Ni13Nb2Cr1 Amorphous form 1.6 85 97 7
Example 3 (Al0.85Si0.15)84Ni10Co3Mo2W1 Amorphous form 1.6 86 94 7
Example 4 (Al0.8Si0.2)80Ni15Fe3Zr1La1 Amorphous form 1.5 90 94 7
Example 5 (Al0.7Si0.3)79Ni15Cu2Ta3Hf1 Amorphous form 1.4 91 95 7
Example 6 (Al0.65Si0.35)76Ni10Mn1Ti2V1Fe10 Amorphous form 1.4 89 97 7
Example 7 [(Al0.8Si0.05Ni0.1Co0.04C0.01)]80Li20 Amorphous form 1.7 86 98 3
Example 8 [(Al0.9Si0.1)0.84Ni0.13Nb0.02Cr0.01]80Li20 Amorphous form 1.7 87 97 3
Example 9 [(Al0.8Si0.2)0.84Ni0.1Co0.03Mo0.02W0.01]85Li15 Amorphous form 1.7 88 96 3
Example 10 [(Al0.7Si0.3)0.8Ni0.15Fe0.03Zr0.02]85Li15 Amorphous form 1.6 92 96 3
Example 11 [(Al0.6Si0.4)0.78Ni0.1Cu0.08Ta0.03Hf0.01]90Li10 Amorphous form 1.5 92 95 3
Example 12 [(Al0.5Si0.5)0.76Ni0.15Fe0.05Mn0.01Ti0.02V0.01]88Li12 Amorphous form 1.5 90 95 3
TABLE 2
Negative electrode material Characteristics of battery
Alloy composition Microcrystalline phase Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge
Ratio (%) Average particle diameter (nm)
Example 13 (Al0.8Si0.2)85Ni10Co3Nb2 30 30 1.6 86 97 7
Example 14 (Al0.7Si0.3)84Ni10Fe2Nb2Cr1P1 60 50 1.8 85 97 7
Example 15 (Al0.5Si0.5)78Ni10Fe7W2Mo1Ge2 80 70 1.4 87 94 7
Example 16 (Al0.6Si0.4)80Ni10Co7Ta1Pb1Ce1 50 50 1.5 84 94 7
Example 17 (Al0.7Si0.3)77Ni14Cu4Zr3Hf1Sn1 100 80 1.5 86 95 7
Example 18 (Al0.6Si0.4)80Ni10Mn1Co5Ti3V1 100 120 1.6 85 97 7
Example 19 [(Al0.7Si0.3)0.8Ni0.12Co0.05Nb0.03)]80Li20 20 40 1.7 87 98 3
Example 20 [(Al0.8Si0.2)0.84Ni0.1Fe0.02Nb0.02Cr0.01P0.01]80Li20 50 70 1.9 86 97 3
Example 21 [(Al0.6Si0.4)0.77Ni0.1Fe0.08W0.02Mo0.01Ge0.02]85Li15 100 90 1.5 91 96 3
Example 22 [(Al0.5Si0.5)0.8Ni0.1Co0.07Ta0.02Pb0.01]85Li15 90 80 1.6 85 96 3
Example 23 [(Al0.75Si0.25)0.77Ni0.14Cu0.04Zr0.03Hf0.01Sn0.01]90Li10 80 80 1.6 87 95 3
Example 24 [(Al0.8Si0.2)0.8Ni0.1Mn0.01Co0.05Ti0.03V0.01]88Li12 100 120 1.8 86 95 3
Example 25 (Al0.7Si0.3)75Fe10Ni10Cr5 20 30 1.5 87 96 7
Example 26 (Al0.5Si0.5)75Fe10Ni10Cr5 30 60 1.7 85 96 7
Example 27 (Al0.3Si0.7)75Fe10Ni10Cr5 50 90 1.8 82 96 7
TABLE 3
Negative electrode material Characteristics of battery
Alloy composition Microcrystalline phase Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge
Ratio (%) Average particle diameter (nm)
Comparative example 1 C - 5000 1 70 80 7
Comparative example 2 Al 100 10000 3 2 40 Can not measure
Comparative example 3 Sn30CO70 Amorphous form - 1.1 80 82 9
Comparative example 4 Si33Ni67 100 40 1.0 82 85 9
Comparative example 5 (Al0.1Si0.9)33Ni67 100 300 1.0 55 70 7
Comparative example 6 Cu50Ni25Sn25 100 200 1.0 70 75 8
Comparative example 7 Si25Fe75 100 300 0.7 65 70 7
Comparative example 8 Ni(Si0.8Al0.2)2 100 400 1.2 60 65 5
Comparative example 9 (Al0.1Si0.9)75Fe10Ni10Cr5 80 150 1.5 60 80 7
Comparative example 10 Si75Fe10Ni10Cr5 100 300 1.2 55 70 6
As is clear from tables 1 to 3, the secondary batteries of examples 1 to 27 were excellent in discharge capacity, capacity retention rate at 300 cycles, and rate characteristics.
In contrast, the secondary battery of comparative example 1, in which carbide was used as the negative electrode material, was inferior to examples 1 to 27 in discharge capacity, capacity retention rate at 300 cycles, and rate characteristics. The secondary battery of comparative example 2, in which Al metal was used as the negative electrode material, had a higher discharge capacity than examples 1 to 27, but had a poor capacity retention rate and rate characteristics at 300 cycles. The ratio characteristics of the secondary batteries of comparative examples 3 to 7 were inferior to those of examples 1 to 27.
When the negative electrodes were observed after 300 cycles of charge and discharge, no change was observed in the alloys in the negative electrode materials used in examples 1 to 24, and dendrites of Al were precipitated in the negative electrode of comparative example 2. The Al dendrite deposition was estimated to be high in the initial battery discharge capacity of the secondary battery of comparative example 2, and the capacity retention rate after 300 cycles was significantly reduced. Al dendrite easily reacts with the electrolyte, and thus the battery safety is lowered.
By comparing examples 25 to 27 with comparative examples 9 to 10, the capacity retention rate and the rate characteristics at 300 cycles can be improved when the atomic ratio x of Si is less than 0.75.
On the other hand, the secondary battery of comparative example 8 using the alloy having the composition described in Japanese patent application laid-open No. Hei 10-302770 had a capacity maintenance rate as low as 60% and a rate characteristic deteriorated to 65% at 300 cycles.
(examples 28 to 37)
< preparation of negative electrode >
The elements in the ratios shown in table 4 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 0.6mm phi into a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and quenched to produce a ribbon-like alloy. The same alloy can be obtained by either allowing the atmosphere to be atmospheric gas during quenching or allowing an inert gas to flow toward the tip of the nozzle.
The crystallinity of the alloys of examples 28 to 37 was measured by X-ray diffraction, and it was confirmed that no peak based on the crystal phase was observed.
The ribbon-shaped alloys of examples 28 to 30 and 36 to 37 were cut and pulverized by a jet mill to obtain alloy powders having an average particle size of 10 μm. The ribbon-like alloys of examples 31 to 35 were cut, then subjected to a heat treatment at 300 ℃ or lower for 5 hours to maintain the amorphous phase and embrittle the alloy as it is, and further pulverized by a jet mill to obtain alloy powders having an average particle size of 10 μm.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 38 to 39)
Alloys having the compositions shown in Table 4 below were produced by a mechanical alloying method. The crystallinity of the obtained alloy was measured by X-ray diffraction. It was confirmed that no peak based on the crystal phase was observed. Further, the resultant was pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 40 to 41)
The elements in the ratios shown in table 5 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 0.6mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 45m/s in an inert atmosphere, and quenched to obtain a thin ribbon-like or flake-like alloy. The crystallinity of the obtained alloy was measured by an X-ray diffraction method, and it was confirmed that no peak based on the crystal phase was observed.
The alloy was heat-treated in an inert atmosphere at 350 ℃ or higher than the crystallization temperature for 1 hour, cut, and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases of the obtained alloy were measured in the same manner as in example 13, and the results are shown in table 5 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 42 to 43)
The elements in the ratios shown in table 5 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 0.7mm in diameter onto a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and quenched to obtain a thin sheet alloy. The alloy was cut and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases of the obtained alloy were measured in the same manner as in example 13, and the results are shown in table 5 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 44 to 45)
The elements in the ratios shown in table 5 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 0.7mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and rapidly cooled to obtain a flake alloy. The alloy was heat-treated at 300 ℃ for 1 hour to adjust the microstructure. The alloy was cut and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The obtained alloy was subjected to the measurement of the ratio of the microcrystalline phases and the measurement of the average crystal grain size of the microcrystalline phases in the same manner as in example 13, and the results are shown in table 5 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
Examples 46 to 47
The elements in the ratios shown in table 5 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 0.5mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 35m/s in an inert atmosphere, and rapidly cooled to obtain a thin ribbon-like or flake-like alloy. The crystallinity of the obtained alloy was measured by an X-ray diffraction method, and it was confirmed that no peak based on the crystal phase was observed.
The alloy was heat-treated at 300 ℃ for 1 hour in an inert atmosphere, cut, and pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases of the obtained alloy were measured in the same manner as in example 13, and the results are shown in table 5 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 48 to 49)
The elements in the ratios shown in table 5 were heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 0.45mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 45m/s in an inert atmosphere, and quenched to obtain a thin sheet alloy.
The alloy was subjected to heat treatment at 300 ℃ for 1 hour to embrittle the alloy, and then cut into pieces, which were pulverized by a jet mill to obtain alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 5 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
(examples 50 to 51)
Alloys having the compositions shown in the following Table 5 were produced by a mechanical alloying method. Further, the resultant was pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.
The ratio of the microcrystalline phases and the average crystal grain size of the microcrystalline phases were measured for the obtained alloy in the same manner as in example 13, and the results are shown in table 5 below.
A lithium ion secondary battery was fabricated in the same manner as described in example 1 above, except that this alloy powder was used.
Comparative examples 11 to 13
As a negative electrode material, Al is prepared by a single-roll method3Mg4Alloy, Al8Mg5Alloy, Cu3Mg2An Si alloy. The roller is made of BeCu alloy, and the rotating speed of the roller is 30 m/s. The microcrystallization of the obtained alloy was confirmed by X-ray diffraction. The average particle diameter was calculated by the Scherrer formula and is shown in table 6 below. Except for using this alloy, a lithium ion secondary battery was fabricated by the same operation as described in example 1 above.
The obtained secondary batteries of examples 28 to 51 and comparative examples 11 to 13 were evaluated for discharge capacity ratio, capacity retention rate, rate characteristics, and the number of charge and discharge times to reach the maximum capacity in the same manner as described in example 1, and the results are shown in tables 4 to 6 below. Table 6 also shows the results of comparative examples 3 and 6.
TABLE 4
Negative electrode material Characteristics of battery
Alloy composition Metallic structure Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge
Example 28 (Al0.9Mg0.1)87Ni8Co4C1 Amorphous form 1.5 85 95 7
Example 29 (Al0.95Mg0.05)84Ni13Nb2Cr1 Amorphous form 1.5 85 97 7
Example 30 (Al0.85Mg0.15)84Ni10Co3Mo2W1 Amorphous form 1.5 86 96 7
Example 31 (Al0.8Mg0.2)80Ni15Fe3Zr1Pr1 Amorphous form 1.4 90 98 7
Example 32 (Al0.75Mg0.15Si0.1)77Ni16Co3Cu1Ta2Hf1 Amorphous form 1.3 91 95 7
Example 33 (Al0.75Mg0.15Si0.1)76Ni17Fe2Mn1Ti3V1 Amorphous form 1.3 89 97 7
Example 34 [(Al0.9Mg0.1)0.87Ni0.08Co0.04C0.01]80Li20 Amorphous form 1.6 86 98 3
Example 35 [(Al0.95Mg0.05)0.84Ni0.13Nb0.02Cr0.01]80Li20 Amorphous form 1.6 87 94 3
Example 36 [(Al0.85Mg0.15)0.84Ni0.1Co0.03Mo0.02W0.01]85Li15 Amorphous form 1.6 88 94 3
Example 37 [(Al0.8Mg0.2)0.8Ni0.1Fe0.08Zr0.02]85Li15 Amorphous form 1.5 92 94 3
Example 38 [(Al0.75Mg0.25)0.78Ni0.15Co0.03Cu0.02Ta0.01Hf0.01]90Li10 Amorphous form 1.4 92 96 3
Example 39 [(Al0.75Mg0.25)0.76Ni0.14Fe0.05Mn0.01Ti0.03V0.01]88Li12 Amorphous form 1.4 90 98 3
TABLE 5
Negative electrode material Characteristics of battery
Alloy composition Microcrystalline phase Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge
Ratio (%) Average particle diameter (nm)
Example 40 (Al0.7Mg0.3)80Ni12Co5Nb2Nd1 90 40 1.5 86 96 7
EXAMPLE 41 (Al0.8Mg0.2)79Ni15Fe2Nb2Cr1P1 70 60 1.7 85 95 7
Example 42 (Al0.5Mg0.5)76Ni11Fe10W1Mo1Ge1 90 80 1.3 87 95 7
Example 43 (Al0.8Mg0.2)80Ni10Co7Ta2Pb1 60 60 1.4 84 96 7
Example 44 (Al0.75Mg0.25)77Ni14Cu4Zr3Hf1Sn1 100 50 1.4 86 94 7
Example 45 (Al0.6Mg0.4)80Ni10Mn1Co5Ti3V1 100 90 1.5 85 92 7
Example 46 [(Al0.8Mg0.2)08Ni0.12Co0.05Nb0.03)]80Li20 100 60 1.6 87 91 3
Example 47 [(Al0.7Mg0.3)0.82Ni0.12Fe0.02Nb0.02Cr0.01P0.01]80Li20 90 80 1.8 86 92 3
Example 48 [(Al0.9MG0.1)0.78Ni0.1Fe0.07W0.02Mo0.01Ge0.02]85Li15 100 110 1.4 91 91 3
Example 49 [(Al0.7Mg0.3)0.8Ni0.1Co0.07Ta0.02Pb0.01]85Li15 90 100 1.5 85 93 3
Example 50 [(Al0.7Mg0.3)0.77Ni0.14Cu0.04Zr0.03Hf0.01Sn0.01]90Li10 90 90 1.5 87 93 3
Example 51 [(Al0.8Mg0.2)0.8Ni0.1Mn0.01Co0.05Ti0.03V0.01]88Li12 100 150 1.7 86 92 3
TABLE 6
Negative electrode material Characteristics of battery
Alloy composition Microcrystalline phase Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge
Ratio (%) Average particle diameter (nm)
Comparative example 3 Sn30Co70 Amorphous form - 1.2 80 82 9
Comparative example 6 Cu50Ni25Sn25 100 200 1.1 70 75 8
Comparative example 11 Al3Mg4 100 500 1.0 60 75 8
Comparative example 12 Al8Mg5 100 600 1.0 70 75 8
Comparative example 13 Cu3Mg2Si 100 400 0.9 75 77 8
As is clear from tables 4 to 6, the secondary batteries of examples 28 to 51 were excellent in discharge capacity, capacity retention rate at 300 cycles and rate characteristics.
In contrast, the secondary batteries of comparative examples 3 and 6 using the alloy having an Sn content of more than 20 atomic% were inferior to those of examples 28 to 51 in discharge capacity, capacity retention rate at 300 cycles, and rate characteristics. The secondary batteries of comparative examples 11 and 12 using a binary alloy of Al and Mg and the secondary battery of comparative example 13 using a ternary alloy of Cu, Mg and Si had inferior capacity retention rate and rate characteristics at 300 cycles to those of examples 28 to 51.
(examples 52 to 53)
A master alloy having a composition shown in table 7 was heated and melted, and then an alloy was obtained by a single-roll method in an inert atmosphere. That is, an alloy metal solution was injected in an inert atmosphere from a nozzle hole (0.5 mm. phi.) disposed at a gap of 0.5mm between the roll and the nozzle to a cooling roll (roll material is BeCu alloy, roll diameter is 500mm, roll width is 150mm) rotating at a speed of 25m/s to obtain a sample plate thickness of 15 μm, and the sample plate was quenched to obtain a ribbon-like alloy.
The alloys of examples 52 to 53 were subjected to the following evaluation tests (1) to (4), and the results are shown in tables 7 to 8 below.
(1) Diffraction by X-ray
The obtained alloy was subjected to powder X-ray diffraction measurement, and diffraction peaks based on the intermetallic compound and diffraction peaks based on the second phase were obtained as shown in table 7. The X-ray diffraction pattern of example 52 is shown in fig. 6. Specifically, the presence of a second phase mainly composed of Al and an intermetallic compound phase was confirmed. In the X-ray diffraction pattern of fig. 6, peaks derived from Al metal were detected at 38.44 °, 44.74 °, 65.04 ° 2 θ, and Si derived from solid solution Al was detected at 27.76 °, 46.22 °, 54.80 °, 67.48 ° 2 θ 2Peak of Ni phase. The plane spacing d is obtained from experimental data expressed by the equation 2dsin θ ═ λ (θ diffraction angle, λ: wavelength of X-ray). The intermetallic compound of the first phase was presumed to be fluorite (CaF) from the X-ray diffraction pattern2) Structure, substantially in Si2Al is dissolved in Ni crystal lattice. It was confirmed that other constituent elements were also contained in the phase. The constitutional elements of TEM-EDX of the second phase are shown in table 8 below. The lattice constant of the fluorite structure was calculated from the obtained X-ray diffraction pattern, and the results are shown in table 7 below.
On the other hand, the master alloy used to make the alloys of examples 52 and 53 contained Al3Ni phase and Si2An Ni phase (undissolved Al) and an Al phase. From Si by comparing the X-ray diffraction patterns of the master alloys2Diffraction angle of Ni peak and Si from X-ray diffraction pattern of FIG. 62The diffraction angle of the peak of Ni confirmed that Si contained in the alloys of examples 52 and 532Al is dissolved in the Ni phase.
The relative intensity ratio of the fluorite structure to the strongest diffraction intensity according to the intermetallic compound varies depending on the alloy composition, passing Al through Si2Ni phase or Si2The solid solution ratio in the Co phase shifts the diffraction angle. The master alloys used to make the alloys of the various embodiments in the case of AlSi-based, From Al3Ni phase, Si2Ni phase (undissolved Al) and Al phase, and further contains Al according to the composition3Ni2And (4) phase(s). On the other hand, Al is used for AlSiCo-based9Co2Phase, Si2A Co phase and an Al phase. The maximum diameter of the grains in the master alloy is over 500nm, in all cases in the order of microns.
(2) Observation with Transmission Electron Microscope (TEM)
Taking a TEM photograph (10 ten thousand times) confirms that the metal structure is isolated and precipitated in at least a part of intermetallic compound crystal particles, and a second phase mainly composed of an element that alloys with lithium is embedded and precipitated between islands formed by the precipitation. A Transmission Electron Microscope (TEM) photograph of the alloy of example 52 is shown in fig. 7. In fig. 7, isolated crystal grains (black) are intermetallic compound crystal particles 21, and a phase (gray) buried between the isolated crystal grains 21 is a second phase 22. As can be seen from fig. 7, the network of the second phase is cut off, and a part of the second phase is isolated.
For 50 intermetallic compound crystal particles adjacent to each other in the TEM photograph, the maximum diameter of each crystal particle was measured, and the average value thereof was taken as the average crystal particle diameter. Examples 52 and 53 were 100nm and 60nm, respectively. Here, when 2 or more intermetallic compound crystal particles are in contact with each other, the maximum length of each intermetallic compound crystal particle dispersed at the grain boundary is defined as the crystal grain diameter.
In addition, the distances between arbitrary 50 intermetallic compound crystal particles were measured for 50 intermetallic compound crystal particles adjacent to each other in the TEM photograph, and the average value thereof was taken as the distance between the intermetallic compound crystal particles, which was 60nm and 30nm in examples 52 and 53, respectively.
In one field of view of the TEM photograph, the area ratio (%) of the first phase was determined by image processing in a region (area 100%) containing at least 50 intermetallic compound crystal particles, and the area ratio (%) of the first phase was removed from the area (100%) of the entire region to obtain the area ratio of the second phase, i.e., the occupancy of the second phase in the negative electrode material. Examples 52 and 53 were 17% and 30%, respectively. Here, when 2 or more intermetallic compound crystal particles are in contact with each other, the number of intermetallic compound crystal particles dispersed at the grain boundaries is counted without counting one.
Next, the alloy was measured for each 1 μm by the method described below2The number of intermetallic compound crystal particles per area was found to be 80 and 205 for the alloys of examples 52 and 53, respectively.
That is, 1 μm in one field of view of the TEM photograph is counted2The number of islands of the intermetallic compound in the range of (a). In this case, the number of islands on the boundary line of 1 μm × 1 μm to be divided is 1.
The results are shown in table 10, where, when 2 or more intermetallic compound crystal particles are in contact with each other, the number of intermetallic compound crystal particles dispersed at the grain boundaries is counted without counting one.
(3) Differential scanning calorimetry
Differential Scanning Calorimetry (DSC) was performed at a temperature rise rate of 10 ℃/min under an inert atmosphere, and the temperature at which the non-equilibrium phase shifts to the equilibrium phase was evaluated by the exothermic peak. The DSC curve of the alloy of example 52 is shown in FIG. 8. The intersection of the line of least change in the exothermic peak (baseline) and the maximum slope of the exothermic peak is the transition temperature, and is shown in table 8 below. An initial exothermic peak was seen at 293 ℃ in example 52 and 267 ℃ in example 53. The transition temperature determined by this method is a temperature relatively close to the rise of the exothermic peak.
(4) TEM-EDX (energy dispersive X-ray diffraction)
It was confirmed by TEM-EDX that other elements were dissolved in the second phase of each alloy at a ratio of 10 atomic% or less. The second phase of the alloy of example 52 contains 3 at% Si and 2.5 at% Ni, and the second phase of the alloy of example 53 contains 2.2 at% Si and 1.9 at% Ni.
(1) After the evaluation of (1) to (4), the alloys of examples 52 and 53 were cut and pulverized by a jet mill to obtain alloy powders having an average particle size of 10 μm.
A lithium ion secondary battery was produced in the same manner as described in example 1 above, except that the obtained alloy powder was used.
(examples 54 to 72)
After heating and melting master alloys having the compositions shown in tables 8 and 9, an alloy metal solution was ejected from a nozzle hole (0.5 mm. phi.) disposed with a gap of 0.5mm between the roll and the nozzle by a single roll method in an inert atmosphere onto a cooling roll (roll material is BeCu alloy, roll diameter is 500mm, roll width is 150mm) rotating at a speed of 25m/s to obtain a sample plate having a thickness of 15 μm, and the plate was quenched to obtain a thin strip alloy.
The obtained alloys of examples 54 to 72 were subjected to the evaluation tests of (1) X-ray diffraction, (2) TEM observation, and (3) TEM-EDX composition analysis in the same manner as in examples 52 and 53, and the results are shown in tables 8 to 11 below.
(1) After the evaluation of (1) to (4), the alloys of examples 54 to 72 were cut and pulverized by a jet mill to obtain alloy powders having an average particle size of 10 μm.
A lithium ion secondary battery was produced in the same manner as described in example 1 above, except that the obtained alloy powder was used.
Comparative example 14
Except that Si of inverse fluorite structure having a lattice constant of 5.466.7Ni33.3A lithium ion secondary battery was produced in the same manner as described in example 1 above, except that the negative electrode material was used.
Comparative example 15
Except for using a fluorite-structured Mg having a lattice constant of 6.3566.7Si33.3A lithium ion secondary battery was obtained in the same manner as described in example 1 except that the negative electrode material was changed to a materialAnd (4) a pool.
Comparative example 16
The raw material is dissolved at a high frequency in an Ar atmosphere to form a metal solution, the metal solution is poured into a tundish, a thin stream of the metal solution is formed through a fine hole provided in the bottom of the tundish, and high-pressure Ar gas is sprayed on the thin stream of the metal solution to form powder.
The cross section of the obtained negative electrode material powder was observed by SEM (scanning electron microscope) and EPMA analysis of each phase confirmed that the composition was Co42Si58The CoSi phase precipitates as a primary crystal, and the Si phase and a part of the CoSi phase form a lamellar eutectic crystal. The average thickness (minor axis particle diameter) of the Si layer is 0.1 to 2 μm.
A lithium ion secondary battery was produced in the same manner as described in example 1 above, except that this anode material was used.
The secondary batteries of examples 54 to 72 and comparative examples 14 to 16 were measured for their discharge capacity ratio, capacity retention rate, rate characteristics, and number of charge/discharge cycles to the maximum capacity, which were the same as those described in example 1, and the results are shown in tables 8 to 11 below.
TABLE 7
Examples Composition of X-ray diffraction peak d (. alpha.) based on first phase X-ray diffraction peak d (. alpha.) based on second phase Lattice constant of intermetallic Compound (. alpha.)
52 (Al0.65Si0.35)75Ni25 3.2101 1.9658 1.6764 1.3902 1.2756 2.3399 2.0239 1.4328 1.2211 5.560
53 (Al0.8Si0.2)80Ni20 3.3311 2.0389 1.7380 1.4420 1.3210 2.3434 2.0308 1.4332 1.2244 5.770
TABLE 8
Alloy composition Second phase composition Intermetallic compound Lattice constant (. alpha.) Transition temperature (. degree. C.) Elemental monomer occupancy (%)
Example 52 (Al0.65Si0.35)75Ni25 Al body + Si + Ni CaF2Structure of the product 5.56 293 17
Example 53 (Al0.8Si0.2)80Ni20 Al body + Si + Ni CaF2Structure of the product 5.77 267 30
Example 54 (Al0.55Si0.45)77.5Co17.5Ni5 Al body + Si + Co + Ni CaF2Structure of the product 5.51 350 15
Example 55 (Al0.6Si0.4)77Ni20Co3 Al body + Si + Ni + Co CaF2Structure of the product 5.54 290 18
Example 56 (Al0.6Si0.4)77Ni20Fe3 Al body + Si + Ni + Fe CaF2Structure of the product 5.54 320 22
Example 57 (Al0.7Si0.3)76Ni22Nb2 Al body + Si + Ni CaF2Structure of the product 5.72 365 8
Example 58 (Al0.7Si0.3)76Ni18Co5Ta1 Al body + Si + Ni + Co CaF2Structure of the product 5.67 310 10
Example 59 (Al0.7Si0.3)76Ni18Co5La1 Al body + Si + Ni + Co CaF2Structure of the product 5.64 340 13
Example 60 (Al0.5In0.1Si0.4)76Ni18Co5Ce1 Al body + Si + In + Ni CaF2Structure of the product 5.82 262 12
Example 61 (Al0.5Bi0.1Si0.4)76Ni18Co6 Al body + Si + Bi + Ni CaF2Structure of the product 5.79 270 11
Example 62 (Al0.5Pb0.1Si0.4)76Ni18Mn6 Al body + Si + Pb + Ni CaF2Structure of the product 5.88 285 9
Example 63 (Al0.5Zn0.1Si0.4)76Ni18Cu6 Al body + Si + Zn + Ni CaF2Structure of the product 5.56 295 16
Example 64 (Al0.5Ga0.1Si0.4)76Ni18Co4Ti2 Al body + Si + Ga + Ni CaF2Structure of the product 5.50 248 23
Example 65 (Al0.5Sb0.1Si0.4)76Ni18Co5Zr1 Al body + Si + Sb + Ni CaF2Structure of the product 5.55 288 15
Example 66 (Al0.5Mg0.1Si0.4)76Ni18Co5Hf1 Al host + Si + Mg + Ni CaF2Structure of the product 5.80 285 15
Example 67 (Al0.5Sn0.1Si0.4)76Ni18Co4Cr2 Al body + Si + Sn + Ni CaF2Structure of the product 5.63 270 20
TABLE 9
Alloy composition Second phase composition Intermetallic compound Lattice constant (. alpha.) Transition temperature (. degree. C.) Elemental monomer occupancy (%)
Example 68 [(Al0.65Si0.35)75Ni25]90Li10 Al host + Si + Ni + Li CaF2Structure of the product 5.52 263 19
Example 69 [(Al0.8Si0.2)80Ni20]90Li10 Al host + Si + Ni + Li CaF2Structure of the product 5.73 257 33
Example 70 [(Al0.55Si0.45)77.5Co1.75Ni5]88Li12 Al host + Si + Co + Ni + Li CaF2Structure of the product 5.47 330 18
Example 71 [(Al0.65Si0.35)77Ni20Co3]92Li8 Al host + Si + Ni + Co + Li CaF2Structure of the product 5.50 270 21
Example 72 [(Al0.6Si0.4)76Ni20Fe4]90Li10 Al host + Si + Ni + Fe + Li CaF2Structure of the product 5.50 300 25
Comparative example 14 Si66.7Ni33.3 - Inverted fluorite structure 5.4 - -
Comparative example 15 Mg66.7Si33.3 - CaF2Structure of the product 6.35 - -
Comparative example 16 Co42Si58 - CoSi2Phase + CoSi phase 5.35 - 15(Si phase)
Watch 10
First phase Characteristics of battery
Average crystal grain size (nm) Number of grains (number) Average distance between grains (nm) Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of discharges at maximum capacity
Example 52 100 80 60 1.6 89 97 7
Example 53 60 205 30 1.6 89 96 7
Example 54 80 120 60 1.5 91 95 7
Example 55 50 280 35 1.7 90 92 7
Example 56 120 65 70 1.6 89 94 7
Example 57 60 350 30 1.5 93 94 7
Example 58 40 800 20 1.4 94 93 7
Example 59 50 320 30 1.5 93 95 7
Example 60 50 300 35 1.7 90 93 7
Example 61 50 320 30 1.7 89 93 7
Example 62 50 340 30 1.6 89 92 7
Example 63 50 280 40 1.6 89 92 7
Example 64 80 100 70 1.6 90 91 7
Example 65 60 250 40 1.5 91 92 7
Example 66 60 270 35 1.5 90 91 7
Example 67 50 290 30 1.6 90 92 7
TABLE 11
First phase Characteristics of battery
Average crystal grain size (nm) Number of grains (number) Average distance between grains (nm) Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of discharges at maximum capacity
Example 68 90 100 50 1.6 87 94 2
Example 69 60 205 30 1.6 87 93 2
Example 70 80 120 60 1.5 90 92 2
Example 71 50 280 35 1.7 87 90 2
Example 72 120 65 70 1.6 89 91 2
Comparative example 14 2000 1 - 0.8 40 20 -
Comparative example 15 3000 1 - 1 65 80 8
Comparative example 16 800 2 200 1 70 80 8
As is apparent from tables 8 to 11, the secondary batteries of examples 52 to 72 are superior in discharge capacity, capacity maintenance rate and rate characteristics to the secondary batteries of comparative examples 14 to 16, and the number of charge and discharge times to reach the maximum discharge capacity is reduced.
< comparison of characteristics of alloy containing amorphous phase and alloy containing microcrystalline phase >
The secondary batteries of examples 2, 3, 10 and 11 using the alloy composed of the amorphous phase and the secondary batteries of examples 17 and 18 using the alloy composed of the microcrystalline phase were selected from the above examples 1 to 51, and the secondary batteries of examples 52, 54, 55, 68 and 71 were manufactured.
An alloy (example 73) having a composition shown in table 12 below was produced in the same manner as in example 1. Then, a lithium ion secondary battery of example 73 was produced using the alloy in the same manner as described in example 1 above.
Charge and discharge cycle tests were carried out on these secondary batteries at room temperature and 60 ℃ under the same conditions as described in example 1 above. The discharge capacity after 100 cycles at room temperature was defined as 100%, and the discharge capacity after 100 cycles at 60 ℃ was shown, and the results are shown in table 12 below as high-temperature cycle characteristics. In the charge-discharge cycle test at 60 ℃, the discharge capacity at 300 cycles was determined with the maximum discharge capacity being 100%, and the results are shown in table 12 below as the capacity retention rate at 60 ℃.
TABLE 12
Negative electrode Characteristics of battery
Alloy composition Metallic structure Discharge capacity ratio Capacity retention rate at 60 DEG C High temperature cycle characteristics (%)
Example 2 (Al0.95Si0.05)84Ni13Nb2Cr1 Amorphous form 1.6 68 90.8
Example 3 (Al0.85Si0.15)84Ni10Co3Mo2W1 Amorphous form 1.6 65 88.4
Example 10 [(Al0.7Si0.2)0.8Ni0.15Fe0.03Zr0.02]85Li15 Amorphous form 1.6 63 86.5
Example 11 [(Al0.6Si0.4)0.78Ni0.1Cu0.08Ta0.03Hf0.01]90Li10 Amorphous form 1.5 66 85.5
Example 73 (Al0.8Si0.2)82Ni16Nb2 Amorphous form 1.6 70 89.1
Example 17 (Al0.7Si0.3)77Ni14Cu4Zr3Hf1Sn1 Microcrystals 1.5 80 95.8
Example 18 (Al0.6Si0.4)80Ni10Mn1Co5Ti3V1 Microcrystals 1.6 77 95.5
Example 52 (Al0.65Si0.35)75Ni25 Microcrystals 1.6 77 96.5
Example 54 (Al0.55Si0.45)77.5Co17.5Ni5 Microcrystals 1.5 82 97.2
Example 55 (Al0.6Si0.4)77Ni20Co3 Microcrystals 1.7 81 97.4
Example 68 [(Al0.65Si0.35)75Ni25]90Li10 Microcrystals 1.6 79 95.2
Example 71 [(Al0.65Si0.35)77Ni20Co3]92Li8 Microcrystals 1.7 79 94.9
As is apparent from table 12, the secondary batteries of examples 17, 18, 52, 54, 55, 68 and 71, which were provided with the alloy containing the microcrystalline phase, were better in charge-discharge cycle characteristics at 60 ℃ than the secondary batteries of examples 2, 3, 10, 11 and 73, which were provided with the alloy containing the amorphous phase.
(examples 73 to 88)
< preparation of negative electrode >
The master alloys prepared in the atomic% ratios shown in table 13 were heated and melted, and then the alloys were obtained by the single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 1.0mm in diameter into a cooling roll made of BeCu alloy rotating at a speed of 40m/s in an inert atmosphere, and quenched to obtain a ribbon-like alloy. The same alloy can be obtained in both cases where the atmosphere gas during quenching is atmospheric air and where an inert gas is flowed to the tip of the nozzle. These alloys were heat-treated at 450 ℃ for 1.5 hours in a nitrogen atmosphere.
The crystallinity of the alloys of examples 73 to 88 was measured by X-ray diffraction, and it was confirmed that no peak based on the crystal phase was observed.
The crystallinity of the alloys of examples 73 to 88 was measured by X-ray diffraction, and the presence of an Al phase or an Mg phase, which is a monomer phase of an element alloyed with lithium, and two or more intermetallic compound phases X having a stoichiometric composition shown in table 13 below was confirmed. When the compositions between the intermetallic compound phases X are compared, it is found that the kinds of elements that are alloyed with lithium are different from each other.
FIG. 9 shows an X-ray diffraction pattern (X-ray, CuK α) of an alloy of example 73. In FIG. 9, Al monomer phase (indicated by the symbol "O") and Al monomer phase appear3Ni phase (represented by □ symbol), Si monomer phase (represented by X symbol), and Si2Diffraction lines of Ni phase (represented by. DELTA.).
Then, the ribbon-shaped alloys of examples 73 to 88 were cut and pulverized by a jet mill to obtain alloy powders having an average particle size of 10 μm.
94 wt% of the alloy powder, 3 wt% of graphite powder as a conductive material, 2 wt% of styrene butadiene rubber as a binder, and 1 wt% of carboxymethyl cellulose as an organic solvent were mixed and dispersed in water to prepare a suspension. The suspension was applied to a copper foil having a thickness of 18 μm as a current collector, dried, and then compacted to obtain a negative electrode.
< preparation of Positive electrode >
A slurry was prepared by mixing 91 wt% of lithium cobalt oxide powder, 6 wt% of graphite powder, and 3 wt% of polyvinylidene fluoride and dispersing them in N-methyl-2-pyrrolidone. The slurry was applied to an aluminum foil as a current collector, dried, and then compacted to obtain a positive electrode.
< preparation of lithium ion Secondary Battery >
A separator comprising a polyethylene porous film was prepared. The separator was inserted between the positive electrode and the negative electrode, and the electrode group was wound in a spiral shape. Lithium hexafluorophosphate as an electrolyte was dissolved at 1mol/L in a mixed solvent of ethylene carbonate and methyl ethyl carbonate (volume ratio: 1: 2) to prepare a nonaqueous electrolytic solution.
The electrode group was placed in a bottomed cylindrical container made of stainless steel, and then a nonaqueous electrolyte solution was injected to perform sealing treatment, thereby assembling a cylindrical lithium ion secondary battery.
(examples 89 to 104)
The master alloys prepared in the atomic% ratios shown in table 14 were heated and melted, and then the alloys were obtained by the single-roll method in an inert atmosphere. That is, an alloy metal solution was injected from a nozzle hole of 1mm phi into a cooling roll made of BeCu alloy rotating at a speed of 30m/s in an inert atmosphere, and quenched to obtain a ribbon-like alloy. The alloy obtained was heat-treated at 350 ℃ for 1 hour in a nitrogen atmosphere.
The obtained alloys of examples 89 to 104 were measured by thermal analysis under the following conditions, and an exothermic peak was observed at 200 to 350 ℃ to confirm that they contained an unbalanced phase.
< measurement conditions for thermal analysis >
The peak of heat generation at the time of transition from the non-equilibrium phase to the equilibrium phase was determined by measuring the temperature at a temperature rise rate of 10 ℃/min in an inert atmosphere using a differential scanning calorimeter for thermal analysis.
The metallic structures of the alloys of examples 89 to 104 were measured by X-ray diffraction method, and the presence of an Al phase, which is a single phase of an element alloyed with lithium, and two intermetallic compound phases having the stoichiometric compositions shown in table 14 below were confirmed. When the compositions between the intermetallic compound phases are compared, it is found that the kinds of elements alloying with lithium are different from each other. FIG. 10 shows an X-ray diffraction pattern (X-ray, CuK α) of the alloy of example 89. In FIG. 10, a peak (indicated by a circle) based on the Al phase and a peak based on the Si phase appear2Peak of Ni phase (symbolized by. DELTA.), based on Al3The peak of the Ni phase (indicated by symbol X) was observed together with the peak (indicated by symbol □) derived from the non-equilibrium phase (substantially fluorite structure).
A lithium ion secondary battery was fabricated by the same operations as described in example 73 above, except that this alloy powder was used.
Comparative example 17
Mesophase pitch-based carbon fibers (average fiber diameter of 10 μm, average fiber length of 25 μm, and surface spacing d) heat-treated at 3250 ℃ were used in place of the alloy powder0020.3355nm, a specific surface area of 3m by the BET method2A lithium ion secondary battery was produced in the same manner as in example 73 except for the carbon powder in/g).
Comparative example 18
A lithium ion secondary battery was fabricated in the same manner as in example 73 above, except that Al powder having an average particle diameter of 10 μm was used instead of the alloy powder.
Comparative example 19
Manufacture of Sn by mechanical alloying method for 100 hours30Co70And (3) alloying. The resulting alloy was confirmed to be amorphous by X-ray diffraction. A lithium ion secondary battery was fabricated by the same operations as described in example 73 above, except that this alloy was used.
Comparative examples 20 to 22
As a negative electrode material, Si was produced by a single roll method33Ni67Alloy, (Al)0.1Si0.9)33Ni67Alloy, Cu50Ni25Sn25And (3) alloying. The material of the roller is BeCu alloy, and the rotating speed of the roller is 25 m/s. The microcrystallization of the obtained alloy was confirmed by X-ray diffraction. The results of calculating the average particle diameter by the Scherrer equation are shown in table 15 below. A lithium ion secondary battery was fabricated by the same operations as described in example 73 above, except that this alloy was used.
Comparative example 23
As a negative electrode material, Fe was produced by a milling method25Si75And (3) alloying. The average crystal grain size was calculated to be 300nm by the Scherrer formula. A lithium ion secondary battery was fabricated by the same operations as described in example 73 above, except that this alloy was used.
Comparative example 23
Molten AlNi2The alloy represented by Ti was quenched by a single-roll method to obtain a sample of comparative example 24. The production was carried out in an Ar atmosphere using a Cu roll having a diameter of 200 mm. X-ray diffraction measurement was performed, and it was confirmed that the material was an amorphous single phase. The obtained sample was pulverized to obtain an alloy powder having an average particle size of 9 μm. A lithium ion secondary battery was fabricated by the same operations as described in example 73 above, except that this alloy powder was used.
Comparative examples 25 to 27
Production of Ni (Si) by gas atomization1-xAlx)2X in the indicated alloys is 0.1, 0.2 and 0.25. The obtained sample was not subjected to heat treatment, and 15 to 45 μm powder was classified. A lithium ion secondary battery was produced in the same manner as described in example 73 above, except that this anode material was used.
Comparative example 28
Mixing Al and M at a ratio of 12: 1And o, alloying by arc melting. The cooling rate after dissolution is controlled to obtain Al phase and Al 12Mo phase and Al5A Mo phase.
The alloy was pulverized to prepare a negative electrode material having an average particle size of 20 μm. A lithium ion secondary battery was produced in the same manner as described in example 73 above, except that this anode material was used.
The secondary batteries of examples 73 to 104 and comparative examples 17 to 28 were subjected to the following evaluation tests, and the results are shown in tables 13 to 15 below.
1) Measurement of average Crystal particle diameter of microcrystalline phase
As shown in tables 13 to 15, the alloys of examples 73 to 104 contained mixed microcrystalline phases substantially composed of an elemental monomer phase and an intermetallic compound phase. In the alloys of examples 73 to 104, the longest part of the crystal grain taken in the TEM (transmission electron microscope) photograph was defined as the grain size, and 50 crystal grains adjacent to each other were measured in the photograph (for example, 10 ten thousand times) taken in the TEM observation, and the average value of these crystal grains was defined as the average crystal grain size of the intermetallic compound phase. When the islands of the intermetallic compound phase float in the sea of the monomer phase, evaluation was made only by the size of the islands (crystal grains). The magnification of the TEM photograph was changed depending on the crystal grain size.
2) Discharge capacity ratio and capacity retention rate at 300 cycles
For each secondary battery, the following charge-discharge cycle test was performed. That is, after charging was carried out at 20 ℃ for 2 hours with a charging current of 1.5A to 4.2V, discharging was carried out again to 2.7V with 1.5A, and the discharge capacity ratio and the capacity retention rate at 300 cycles were measured. The discharge capacity ratio was represented by a ratio at which the discharge capacity of comparative example 1 was 1, and the capacity retention rate was represented by a discharge capacity at 300 cycles at which the maximum discharge capacity was 100%.
3) Ratio characteristic
After each secondary battery was charged at 20 ℃ for 1 hour at a constant current and constant voltage of 4.2V at a rate of 1C, the discharge capacity was measured at a rate of 0.1C until 3.0V was discharged, and the discharge capacity at 0.1C was obtained. After charging under the same conditions, the discharge capacity was measured at 1C to 3.0V, and the discharge capacity at 1C was obtained. The discharge capacity at 0.1C was defined as 100%, and the discharge capacity at 1C was defined as a rate characteristic.
4) The number of charge/discharge cycles to reach the maximum capacity was measured as the number of cycles required to reach the maximum discharge capacity when each battery was subjected to charge/discharge cycles at 1C.
Watch 13
Negative electrode Characteristics of battery
Alloy composition Precipitated phase Average crystal grain size (nm) Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge times to reach maximum capacity
Example 73 (Al0.4Si0.6)77Ni22Nb1 Al+Al3Ni+Si2Ni+Si 280 1.6 85 91 6
Example 74 (Al0.3Si0.7)78Ni19Ti2Mo1 Al+Al3Ni+Si2Ni 250 1.5 87 92 6
Example 75 (Al0.5Si0.5)76Ni21V2Ta1 Al+Al3Ni+Si2Ni 300 1.7 83 93 6
Example 76 (Al0.4Si0.6)80Ni17Cr2W1 Al+Al3Ni+Si2Ni 320 1.4 85 92 6
Example 77 (Al0.5Si0.5)80Fe15Co2Ta1Pb1 Al+Al3Fe+Si2Fe 300 1.4 86 91 6
Example 78 (Al0.5Ge0.5)79Ni16Fe4Nb1 Al+Al3Ni+GeNi 320 1.6 85 91 6
Example 79 (Al0.6Ge0.4)81Cu14Ni4Mo1 Al+Al2Cu+Ga2Cu 350 1.4 87 88 6
Example 80 (Al0.5In0.5)76Ni23Zr1 Al+Al3Ni+In3Ni2 360 1.5 83 88 6
Example 81 (Al0.5Si0.4Ge0.1)80Ni15Co4Nb1 Al+Al3Ni+Si2Ni+GeNi 270 1.6 85 86 6
Example 82 (Al0.6Bi0.4)80Ni18Nb2 Al+Al3Ni+Bi3Ni 250 1.4 84 88 6
Example 83 (Al0.4Si0.6)76Fe20B4 Al+Al3Fe+Si2Fe 180 1.5 80 84 6
Example 84 (Al0.6Si0.4)72Ni20Cr2B6 Al+Al3Ni+Si2Ni+Al3Ni2 150 1.4 79 85 6
Example 85 (Al0.5Si0.5)74Ni20Co2B4 Al+Al3Ni+Si2Ni 140 1.5 80 85 6
Example 86 (Mg0.9Si0.1)75La6Ni18Nb1 Mg+Si2Ni+Mg2Ni 200 1.4 83 84 6
Example 87 (Mg0.7Al0.3)74Ce10Cu14Zr2 Mg+AlCu+Mg2Cu 180 1.4 82 86 6
Example 88 (Mg0.8Si0.2)73Pr8Ni18Mo1 Mg+Si2Ni+Mg2Ni 230 1.4 83 85 6
TABLE 14
Negative electrode Characteristics of battery
Alloy composition Precipitated phase Average crystal grain size (nm) Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge times to reach maximum capacity
Example 89 (Al0.5Si0.5)75Ni20Cr2Fe2Cu1 Al+Al3Ni+Si2Ni + non-equilibrium phase 230 1.7 86 93 6
Example 90 (Al0.55Si0.45)75Ni20Nb1Mn3Cr1 Al+Al3Ni+Si2Ni + non-equilibrium phase 220 1.7 88 91 6
Example 91 (Al0.5Si0.5)74Ni14Co3Nb1Cu2 Al+Al3Ni+Si2Ni + non-equilibrium phase 200 1.6 89 90 6
Example 92 (Al0.55Si0.45)76Ni14Fe3W1Co3Cu3 Al+Al3Ni+Si2Ni + non-equilibrium phase 190 1.6 87 90 6
Example 93 (Al0.5Si0.5)80Ni12Mn5Ta1Fe2 Al+Al3Ni+Si2Ni + non-equilibrium phase 190 1.4 90 90 6
Example 94 (Al0.5Si0.4Sn0.1)76Ni19Mo1Cu2Cr2 Al+Al3Ni+Si2Ni + non-equilibrium phase 180 1.5 90 90 6
Example 95 (Al0.55Si0.25Ge0.2)76Ni17Cu5Nb1Mo1 Al+Al3Ni+Si2Ni + non-equilibrium phase 160 1.6 89 91 6
Example 96 (Al0.4Si0.5Ga0.1)75Ni19Co3Nb1Mn2 Al+Al3Ni+Si2Ni + non-equilibrium phase 210 1.4 89 91 6
Example 97 (Al0.5Si0.45Zn0.05)78Ni14Fe5Zr1Cu2 Al+Al3Ni+Si2Ni + non-equilibrium phase 180 1.5 89 92 6
Example 98 (Al0.55Si0.45)76Ni18Cu2Nb1Co3 Al+Al3Ni+Si2Ni + non-equilibrium phase 200 1.5 90 93 6
Example 99 (Al0.5Si0.5)80Ni11Cr4B5 Al+Al3Ni+Si2Ni + non-equilibrium phase 150 1.5 84 86 6
Example 100 (A0.6Si0.4)77Ni15Cu3B5 Al+Al3Ni+Si2Ni + non-equilibrium phase 130 1.5 83 86 6
Example 101 (Al0.55Si0.45)82Ni11Co3B4 Al+Al3Ni+Si2Ni + non-equilibrium phase 160 1.5 84 87 6
Example 102 (Mg0.6Si0.1Al0.3)76La9Ni13Cr2 Mg+Al3Ni+Si2Ni + non-equilibrium phase 160 1.6 84 84 6
Example 103 (Mg0.5Si0.2Al0.3)77Ce8Ni13Fe2 Mg+Al3Ni+Si2Ni + non-equilibrium phase 160 1.4 84 86 6
Example 104 (Mg0.6Si0.2Al0.2)76Nd7Ni3Cu2Nb1 Mg+Al3Ni+Si2Ni + non-equilibrium phase 120 1.4 84 85 6
Watch 15
Negative electrode Characteristics of battery
Alloy composition Precipitated phase Average crystal grain size (nm) Discharge capacity ratio Capacity retention rate (%) Ratio characteristics (%) Number of charge and discharge times to reach maximum capacity
Comparative example 17 C - 5000 1 70 80 7
Comparative example 18 Al - 10000 3 2 40 Can not measure
Comparative example 19 Si30Co70 - Amorphous form 1.1 80 82 9
Comparison 20 Sn33Ni67 - 40 1.0 82 85 9
Comparative example 21 (Al0.1Si0.9)33Ni67 - 300 1.0 55 70 7
Comparative example 22 Cu50Ni25Sn25 - 200 1.0 70 75 8
Comparative example 23 Si75Fe25 - 300 1.2 30 50 7
Comparative example 24 AlNi2Ti (roller quenching method) AlNi2Ti 300 0.7 85 80 8
Comparative example 25 Ni(Si0.9Al0.1)2(gas atomization method) Si2Ni+AlNi 600 1.3 75 75 7
Comparative example 26 Ni(Si0.8Al0.2)2(gas atomization method) Si2Ni+AlNi 700 1.2 77 75 7
Comparative example 27 Ni(Si0.75Al0.25)2(gas atomization method) Si2Ni+AlNi 600 1.1 79 75 7
Comparative example 28 AlMo series alloy (Slow Cooling) Al+Al12Mo+Al5Mo 800 1.0 70 75 8
As is clear from Table 13, the alloy compositions of examples 73 to 78, 80 and 81 belong to the above general formulae (9), (10) and (13), the alloy compositions of examples 83 to 85 belong to the above general formula (11), and the secondary batteries of the alloy compositions of examples 86 to 88 belong to the above general formula (12). The alloy compositions of examples 73 to 88 all contained a monomer phase of an element alloying with lithium and two or more intermetallic compound phases X, and therefore the discharge capacity ratio was 1.4 or more, the capacity retention rate at 300 cycles was 79% or more, the rate characteristics were 84% or more, and the number of charge and discharge to reach the maximum capacity was as small as 6. Among them, the secondary batteries of examples 73 to 78 are better in rate characteristics than those of examples 79 to 88.
As is apparent from Table 14, the alloy compositions of examples 89 to 95 and 98 belong to the above general formulae (9), (10) and (13), the alloy compositions of examples 99 to 101 belong to the above general formula (11), and the secondary batteries of examples 102 to 104 belong to the above general formula (12). The compositions of the alloys of examples 89 to 104 all contained the monomer phase, intermetallic compound phase and non-equilibrium phase X of the elements alloyed with lithium, and therefore the discharge capacity ratio was 1.4 or more, the capacity retention rate at 300 cycles was 83% or more, the rate characteristics were 84% or more, and the number of charge and discharge times to reach the maximum capacity was as small as 6.
In contrast, as is clear from table 15, the secondary battery of comparative example 17 in which carbide was used as the negative electrode material was inferior to examples 73 to 104 in discharge capacity, capacity retention rate at 300 cycles, and rate characteristics. The secondary battery of comparative example 18, in which Al metal was used as the negative electrode material, had a higher discharge capacity than examples 73 to 104, but had a deteriorated capacity retention rate and rate characteristics at 300 cycles.
The discharge capacity of the secondary batteries of comparative examples 19 to 20 was higher than that of examples 73 to 104. The ratio characteristics of the secondary batteries of comparative examples 21 to 23 and 25 to 28 were lower than those of examples 73 to 104. The discharge capacity of the secondary battery of comparative example 24 was lower than that of examples 73 to 104. The number of times of charging and discharging the secondary battery of comparative examples 17 to 28 (except for comparative example 18, which could not be measured) reached the maximum capacity was larger than that of examples 73 to 104.
When the negative electrodes were observed after repeating 300 cycles of charge and discharge, no change in the alloy was observed in the negative electrodes used in examples 73 to 104, and Al dendrites precipitated in the negative electrode of comparative example 18. The precipitation of Al dendrites presumably resulted in the secondary battery of comparative example 18 having a high initial battery discharge capacity, but the capacity retention rate after 300 cycles was significantly reduced. In addition, Al dendrite easily reacts with the electrolyte, thus resulting in a decrease in battery safety.
In the above-described embodiments, the example of application to the cylindrical nonaqueous electrolyte secondary battery was described, but the same is applied to the rectangular nonaqueous electrolyte secondary battery and the thin nonaqueous electrolyte secondary battery.
In the above-described embodiments, the examples applied to the nonaqueous electrolyte secondary battery were described, but the application to the nonaqueous electrolyte primary battery can improve the discharge capacity and the discharge rate characteristic thereof.
As described above, the present invention provides a negative electrode material for a nonaqueous electrolyte battery, a method for producing the same, a negative electrode, and a nonaqueous electrolyte battery, each of which is excellent in discharge capacity, charge-discharge cycle life, and discharge rate characteristics.
The invention provides a negative electrode material for a nonaqueous electrolyte battery, which is excellent in both discharge capacity and rate characteristics, a method for producing the same, a negative electrode, and a nonaqueous electrolyte battery.

Claims (63)

1. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material has the following general formula (1): (Al)1-xSix)aMbM’cTd… … (1) substantially consisting of an amorphous phase, wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and M, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 at%, 50 at%, respectivelyA is more than or equal to 95 atom percent, b is more than or equal to 5 atom percent and less than or equal to 40 atom percent, c is more than or equal to 0 and less than or equal to 10 atom percent, d is more than or equal to 0 and less than 20 atom percent, and x is more than 0 and less than 0.75.
2. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material has the following general formula (2): (A11-xAx)aMbM’cTd… … (2) substantially consisting of an amorphous phase, wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a 50 at% or more and 95 at% or less, b 5 at% or more and 40 at% or less, C0 or more and 10 at% or less, d 0 or more and 20 at% or less, and x 0 < x or less and 0.9.
3. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a 50 at% or more and 95 at% or less, b 5 at% or more and 40 at% or less, C0 or less and 10 at% or less, d 0 or less and 20 at% or less, and x 0 and 0.75 at most.
4. The negative electrode material for nonaqueous electrolyte batteries according to claim 3, wherein the average crystal grain size is 5nm or more and 500nm or less.
5. The negative electrode material for nonaqueous electrolyte batteries according to claim 3, wherein diffraction peaks derived from an intermetallic compound comprising Al and Si appear at d values of at least 3.13 to 3.64. ang. and 1.92 to 2.23. ang. in powder X-ray diffraction measurement, and diffraction peaks derived from Al appear at d values of at least 2.31 to 2.40. ang.
6. The negative electrode material for nonaqueous electrolyte batteries according to claim 3, wherein the microcrystalline phase has a cubic fluorite structure with a lattice constant of 5.42-6.3 or less or an inverse fluorite structure with a lattice constant of 5.42-6.3 or less.
7. The negative electrode material for nonaqueous electrolyte batteries according to claim 3, wherein at least one heat release peak appears in a range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min.
8. The negative electrode material for nonaqueous electrolyte batteries according to claim 3, wherein the microcrystalline phase is a metal phase compound phase containing Al, SI and the element M, at least a part of crystal particles of the intermetallic compound phase are isolated and precipitated from each other, and the negative electrode material for nonaqueous electrolyte batteries further comprises a second phase mainly composed of Al precipitated in a state of being embedded between the isolated crystal particles.
9. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (4): (A11-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atom%, 50 atom% or more and a less than 95 atom%, 5 atom% or more and b less than 40 atom%, and 0 atom% or more and C or less than C or equal to 40 atom%, respectively 10 atomic percent, d is more than or equal to 0 and less than 20 atomic percent, and x is more than 0 and less than or equal to 0.9.
10. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material has the following general formula (5): [ (Al)1-xSix)aMbM’cTd]yLiz… … (5) substantially consisting of an amorphous phase, wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z each satisfy a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. x < 0.75.y + z 100 atomic%, 0. ltoreq. z.50 atomic%.
11. The negative electrode material for a nonaqueous electrolyte battery is further characterized by having the following general formula (6): [ (A1)1-xAx)aMbM’cTd]yLiz… … (6) substantially consisting of an amorphous phase, wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z satisfy a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq. b.ltoreq.0.4, c.ltoreq.0.1, d.ltoreq.0.2, x.ltoreq.0.9, y + z is 100 at%, and z is 0 < z.ltoreq.50 at%.
12. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (7): [ Al ]1-xSix)aMbM’cTd]yLiz… … (7), wherein M represents at least one element selected from the group consisting of Fe, Co, Ni and Mn, and M'The alloy is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d, x, y and z respectively satisfy a + b + C + d being 1, a being 0.5-0.95, b being 0.05-0.4, C being 0-0.1, d being 0-0.2, x being 0-0.75, y + z being 100 atomic percent and z being 0-50 atomic percent.
13. A negative electrode material for a nonaqueous electrolyte battery, characterized in that the material contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z each satisfy a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.9, y + z 100 atomic%, 0. ltoreq. z 50 atomic%.
14. A negative electrode material for a nonaqueous electrolyte battery, which can store and release lithium, characterized in that at least one exothermic peak appears in the range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, and that a diffraction peak based on a crystalline phase appears in X-ray diffraction.
15. A negative electrode material for a nonaqueous electrolyte battery, characterized by comprising a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm and containing two or more elements capable of alloying with lithium, and the second phase comprises an element capable of alloying with lithium as a main component and has a particle diameter of 1 [ mu ] m2The number of the intermetallic compound crystal particles is 10 to 2000, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, andthe second phase is precipitated in a state of being buried between the isolated crystal particles.
16. A negative electrode material for a nonaqueous electrolyte battery, comprising a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, the average distance between the intermetallic compound crystal particles is 500nm or less, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
17. A negative electrode material for a nonaqueous electrolyte battery, comprising a first phase containing intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, and a second phase mainly containing an element capable of alloying with lithium, wherein the intermetallic compound crystal particles have a cubic fluorite structure having a lattice constant of 5.42 to 6.3 a or an inverted fluorite structure having a lattice constant of 5.42 to 6.3 a, at least a part of the intermetallic compound crystal particles are isolated from each other, and the second phase is deposited in a state of being buried between the isolated crystal particles.
18. A negative electrode material for a nonaqueous electrolyte battery, comprising an intermetallic compound phase containing two or more elements capable of alloying with lithium and a second phase mainly composed of an element capable of alloying with lithium, characterized in that in a powder X-ray diffraction measurement, a diffraction peak derived from the intermetallic compound phase appears at d values of at least 3.13 to 3.64-and 1.92 to 2.23-and a diffraction peak derived from the second phase appears at d values of at least 2.31 to 2.40-.
19. A negative electrode material for a nonaqueous electrolyte battery, comprising a single phase of an element that alloys with lithium and a plurality of intermetallic compound phases, wherein at least two of the plurality of intermetallic compound phases respectively contain an element that alloys with lithium and an element that does not alloy with lithium, and wherein combinations of the element that alloys with lithium and the element that does not alloy with lithium are different from each other.
20. A negative electrode material for a nonaqueous electrolyte battery is characterized by comprising a monomer phase of an element that is alloyed with lithium, an intermetallic compound phase, and a nonequilibrium phase.
21. The negative electrode material for nonaqueous electrolyte batteries according to claim 20, wherein the average crystal grain size of the plurality of intermetallic compound phases is in the range of 5 to 500 nm.
22. The negative electrode material for a nonaqueous electrolyte battery according to claim 20, further characterized by having the following general formula (9): xxT1yJz… … (9), wherein X is at least two elements selected from the group consisting of Al, Si, Mg, Sn, Ge, In, Pb, P, and C, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cr, and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W, and rare earth elements, and X, y, and z satisfy X + y + z 100 atomic%, X is 50. ltoreq. x.ltoreq.90, y is 10. ltoreq. y.ltoreq.33, and z is 0. ltoreq. z.ltoreq.10.
23. The negative electrode material for a nonaqueous electrolyte battery according to claim 20, further characterized by having the following general formula (10): a1aT1bJcZd… … (10), wherein A1 represents at least one element selected from the group consisting of Si, Mg and Al, T1 represents at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J represents at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z represents at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C and d each satisfy the relationship a + b + C + d as 100 atomic%, a is 50. ltoreq. a.ltoreq.95, b is 5. ltoreq.40, C is 0. ltoreq.10 and d is 0. ltoreq.20.
24. The negative electrode material for a nonaqueous electrolyte battery according to claim 20, further characterized by having the following general formula (11): t1100-a-0(A21-xJ’x)aBbJc… … (11), wherein T1 represents at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr, and Mn, A2 represents at least one element selected from the group consisting of Al and Si, J represents at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W, and rare earth elements, and J' represents at least one element selected from the group consisting of C, Ge, Pb, P, Sn, and Mg, a, b, C, and x satisfy 10 atom% or less and 85 atom% or less, 0 < b < 35 atom% or less, 0 < C < 10 atom% or less, 0 < x < 0.3, and a Sn content is less than 20 atom% (including 0 atom%).
25. The negative electrode material for a nonaqueous electrolyte battery according to claim 20, further characterized by having the following general formula (12): (Mg)1-xA3x)100-a-b-c-d(RE)aT1bM1cA4d… … (12), wherein A3 is at least one element selected from the group consisting of Al, Si and Ge, RE is at least one element selected from the group consisting of Y and rare earth elements, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, M1 is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, A4 is at least one element selected from the group consisting of Sn, Pb, Zn, P and C, and a, b, C, d and x respectively satisfy 0 < a < 40 atomic%, 0 < b < 40 atomic%, 0 < C < 10 atomic%, 0 < d < 20 atomic%, and 0 < x < 0.5.
26. The negative electrode material for a nonaqueous electrolyte battery according to claim 20, further characterized by having the following general formula (13): (A11-xA5x)aT1bJcZd… … (13), wherein A5 is at least one element selected from the group consisting of Si and Mg, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, and J is at least one element selected from the group consisting of Fe, Co, Ni, Cr and MnCu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and at least one element of rare earth elements, wherein Z is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d and x respectively satisfy a + b + C + d as 100 atomic percent, a is not less than 50 and not more than 95, b is not less than 5 and not more than 40, C is not less than 0 and not more than 10, d is not less than 0 and not more than 20, and x is not less than 0 and not more than 0.9.
27. An anode, characterized in that the anode comprises a lithium secondary battery having the following general formula (1): (Al)1-xSix)aMbM’cTd… … (1), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and M, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atomic%, a is 50 atomic% or more and 95 atomic% or less, b is 5 atomic% or more and 40 atomic% or less, C is 0 atomic% or more and 10 atomic% or less, d is 0 atomic% or more and 20 atomic% or less, and x is 0 < 0.75.
28. An anode, characterized in that the anode comprises a lithium secondary battery having the following general formula (2): (A11-xAx)aMbM’cTd… … (2), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, a is 50 at% or more and 95 at% or less, b is 5 at% or more and 40 at% or less, C is 0 or more and 10 at% or less, d is 0 or more and 20 at% or less, and x is 0 or more and 0.9 or less, respectively.
29. A negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, 50 at% or more and a less than 95 at%, 5 at% or more and b less than 40 at%, 0 or more and C less than 10 at%, 0 or more and d less than 20 at%, and 0 < x < 0.75, respectively.
30. A negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (4): (A11-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atom%, a is 50 atom% or more and 95 atom% or less, b is 5 atom% or more and 40 atom% or less, C is 0 atom% or more and 10 atom% or less, d is 0 atom% or more and 20 atom% or less, and x is 0 < x and 0.9.
31. An anode, characterized in that the anode comprises a lithium secondary battery having the following general formula (5): [ (Al)1-xSix)aMbM’cTd]yLiz… … (5), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z each satisfy a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z.50 atomic%.
32. An anode, characterized in that the anode comprises a lithium secondary battery having the following general formula (6): [ (Al)1-xAx)aMbM’cTd]yLiz… … (6) wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are each a + b + C + d ═ 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.ltoreq.0.9, y + z ═ 100 atomic%, 0. ltoreq. z.ltoreq. 50 atomic%.
33. A negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (7): [ (Al)1-xSix)aMbM’cTd]yLiz… … (7), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z are each a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z 50 atomic%.
34. A negative electrode comprising a microcrystalline phase having an average crystal particle diameter of 500nm or less and having the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, M is at least one element selected from Fe, Co, Ni and Mn, and M' is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elementsT is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are respectively 1 + b + C + d, 0.5-0.95 of a, 0.05-0.4 of b, 0-0.1 of C, 0-0 d-0.2, 0-0 x-0.9, 100 atomic% of y + z, and 0-50 atomic% of z.
35. A negative electrode comprising a negative electrode material capable of occluding and releasing lithium, characterized in that the negative electrode material exhibits at least one exothermic peak in a range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, and exhibits a diffraction peak based on a crystal phase in X-ray diffraction.
36. A negative electrode comprising a negative electrode material, characterized in that the negative electrode material comprises a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm and containing two or more elements alloyable with lithium, and the second phase mainly contains an element alloyable with lithium and has a particle diameter of 1 [ mu ] m 2The number of the intermetallic compound crystal particles is 10 to 2000, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
37. A negative electrode comprising a negative electrode material, wherein the negative electrode material comprises a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, the average distance between the intermetallic compound crystal particles is 500nm or less, and the second phase is precipitated in a state of being buried between the isolated crystal particles.
38. A negative electrode comprising a negative electrode material, wherein the negative electrode material comprises a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, the intermetallic compound crystal particles have a cubic fluorite structure having a lattice constant of 5.42 to 6.3 a or an inverse fluorite structure having a lattice constant of 5.42 to 6.3 a, at least a part of the intermetallic compound crystal particles are isolated from each other and precipitated in a state of being buried between the isolated crystal particles.
39. A negative electrode comprising a negative electrode material, wherein the negative electrode material comprises an intermetallic compound phase containing two or more elements capable of alloying with lithium, and a second phase mainly composed of an element capable of alloying with lithium, and wherein in a powder X-ray diffraction measurement, a diffraction peak from the intermetallic compound phase appears at d values of at least 3.13 to 3.64-and 1.92 to 2.23-and a diffraction peak from the second phase appears at d values of at least 2.31 to 2.40-.
40. A negative electrode comprising a negative electrode material having a single phase of an element that alloys with lithium and a plurality of intermetallic compound phases, wherein at least two of the plurality of intermetallic compound phases respectively contain an element that alloys with lithium and an element that does not alloy with lithium, and combinations of the element that alloys with lithium and the element that does not alloy with lithium are different from each other.
41. A negative electrode comprising a negative electrode material having a monomer phase of an element that is alloyed with lithium, an intermetallic compound phase, and a non-equilibrium phase.
42. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode comprises a nonaqueous electrolyte having the following general formula (1): (Al) 1-xSix)aMbM’cTd… … (1), wherein M is selected from the group consisting of Fe, Co, Ni, Cu and MAt least one element, wherein M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d and x are each 100 atomic% of a + b + C + d, 50 atomic% or more and 95 atomic% of a or less, 5 atomic% or more and 40 atomic% or less of b or less, 0 or more and 10 atomic% or less of C or less, 0 or more and 20 atomic% or less of d or less, and 0 or more and x or less than 0.75.
43. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode comprises a nonaqueous electrolyte having the following general formula (2): (A11-xAx)aMbM’cTd… … (2) wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d and x satisfy the conditions that a + b + C + d is 100 atom%, a is 50 atom% or more and 95 atom% or less, b is 5 atom% or more and 40 atom% or less, C is 0 atom% or less and 10 atom% or less, d is 0 atom% or less and 20 atom% or less, and x is 0.9 or less
44. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (3): (Al)1-xSix)aMbM’cTd… … (3), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d 100 at%, 50 at% or more and a less than 95 at%, 5 at% or more and b less than 40 at%, 0 or more and C less than 10 at%, 0 or more and d less than 20 at%, and 0 < x < 0.75, respectively.
45. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (4): (Al)1-xAx)aMbM’cTd… … (4), wherein A is Mg or Si and Mg, M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atom%, a is 50 atom% or more and 95 atom% or less, b is 5 atom% or more and 40 atom% or less, C is 0 atom% or more and 10 atom% or less, d is 0 atom% or more and 20 atom% or less, and x is 0 < x and 0.9.
46. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode comprises a nonaqueous electrolyte having the following general formula (5): [ (A1)1-xSix)aMbM’cTd]yLiz… … (5), wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, M' is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C, d, x, y and z each satisfy a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z.50 atomic%.
47. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode comprises a nonaqueous electrolyte having the following general formula (6): [ (A1)1-xAx)aMbM’cTd]yLiz… … (6) wherein A is Mg or Si and Mg, and M is at least one element selected from the group consisting of Fe, Co, Ni, Cu and Mn, or an alloy substantially composed of an amorphous phaseM' is at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d, x, y and z are respectively satisfied that a + b + C + d is 1, a is not less than 0.5 and not more than 0.95, b is not less than 0.05 and not more than 0.4, C is not less than 0 and not more than 0.1, d is not less than 0 and not more than 0.2, x is not less than 0.9 and more than 0.9, y + z is 100 atomic percent, and z is not less than 0 and not more than 50 atomic percent
48. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (7): [ (Al)1-xSix)aMbM’cTd]yLiz… … (7), wherein M is at least one element selected from the group consisting of Fe, Co, Ni and Mn, M' is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d, x, y and z are each a + b + C + d 1, 0.5. ltoreq. a.ltoreq.0.95, 0.05. ltoreq. b.ltoreq.0.4, 0. ltoreq. c.ltoreq.0.1, 0. ltoreq. d.0.2, 0. ltoreq. x.0.75, y + z 100 atomic%, 0. ltoreq. z 50 atomic%.
49. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a microcrystalline phase having an average crystal particle diameter of 500nm or less and has the following general formula (8): [ (Al)1-xAx)aMbM’cTd]yLiz… … (8), wherein A is Mg or Si and Mg, M is at least one element selected from Fe, Co, Ni and Mn, M' is at least one element selected from Cu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and rare earth elements, T is at least one element selected from C, Ge, Pb, P and Sn, a, b, C, d, x, y and z satisfy a + b + C + d 1, a is 0.5. ltoreq. a.ltoreq.0.95, b is 0.05. ltoreq.0.4, C is 0. ltoreq.0.1, d is 0. ltoreq. 0.2, x is 0. ltoreq.0.9, y + z is 100 atomic%, and z is 0. ltoreq. z.50 atomic%.
50. A nonaqueous electrolyte battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode contains a negative electrode material capable of occluding and releasing lithium, and is characterized in that the negative electrode material exhibits at least one exothermic peak in the range of 200 to 450 ℃ in Differential Scanning Calorimetry (DSC) at a temperature rise rate of 10 ℃/min, and exhibits a diffraction peak based on a crystal phase in X-ray diffraction.
51. A nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode material comprises a first phase containing intermetallic compound crystal particles having an average crystal particle diameter of 5 to 500nm and containing two or more elements alloyable with lithium, and a second phase mainly containing an element alloyable with lithium and having a particle diameter of 1 μm2The number of the intermetallic compound crystal particles is 10 to 2000, at least a part of the intermetallic compound crystal particles are isolated and precipitated from each other, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
52. A nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode, and a nonaqueous electrolyte, wherein the negative electrode material comprises a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, at least a part of the intermetallic compound crystal particles are isolated and precipitated, the average distance between the intermetallic compound crystal particles is 500nm or less, and the second phase is precipitated in a state of being embedded between the isolated crystal particles.
53. A nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode material comprises a first phase and a second phase, wherein the first phase comprises intermetallic compound crystal particles containing two or more elements capable of alloying with lithium and having an average crystal particle diameter of 5 to 500nm, the second phase mainly contains an element capable of alloying with lithium, the intermetallic compound crystal particles have a cubic fluorite structure having a lattice constant of 5.42 to 6.3 a or a reverse fluorite structure having a lattice constant of 5.42 to 6.3 a, at least a part of the intermetallic compound crystal particles are isolated from each other, and the second phase is isolated by being buried between the isolated crystal particles.
54. A nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode material comprises an intermetallic compound phase containing two or more elements capable of alloying with lithium and a second phase mainly composed of an element capable of alloying with lithium, and wherein in a powder X-ray diffraction measurement, a diffraction peak derived from the intermetallic compound phase appears when a d value is at least 3.13 to 3.64-and 1.92 to 2.23-and a diffraction peak derived from the second phase appears when a d value is at least 2.31 to 2.40-.
55. A nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode material, a positive electrode and a nonaqueous electrolyte, wherein the negative electrode material comprises a single phase of an element that alloys with lithium and a plurality of intermetallic compound phases, and wherein at least two of the plurality of intermetallic compound phases respectively contain an element that alloys with lithium and an element that does not alloy with lithium, and combinations of the element that alloys with lithium and the element that does not alloy with lithium are different from each other.
56. A nonaqueous electrolyte battery is characterized by comprising a negative electrode containing a negative electrode material, a positive electrode, and a nonaqueous electrolyte, wherein the negative electrode material comprises a monomer phase of an element that is alloyed with lithium, an intermetallic compound phase, and a nonequilibrium phase.
57. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by injecting a metal solution containing first to third elements, the first element being at least one element selected from the group consisting of Al, In, Pb, Ga, Sb, Bi, Sn and Zn, onto a single roll, rapidly cooling the solution to a thickness of 10 to 500 [ mu ] m, and solidifying a metal structure containing a high-melting-point intermetallic compound phase containing the first to third elements and a second phase having a melting point lower than that of the intermetallic compound phase, wherein the second element is at least one element selected from the group consisting of elements other than Al, In, Pb, Ga, Sb, Bi, Sn and Zn, and the third element is an element capable of forming an intermetallic compound with the first element and the second element.
58. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by injecting a metal solution containing Al, an element N1, an element N2 and an element N3 into a single roll, rapidly cooling the metal solution to a thickness of 10 to 500 [ mu ] m, and solidifying a metal structure containing an intermetallic compound phase having a high melting point and a second phase, the intermetallic compound phase containing Al, an element N1 and an element N2, the second phase being mainly Al and having a melting point lower than that of the intermetallic compound phase, wherein the element N1 is Si or Si and Mg, the element N2 is at least one element selected from Ni and Co, the element N3 is at least one element selected from In, Bi, Pb, Sn, Ga, Sb, Zn, Fe, Cu, Mn, Cr, Ti, Zr, Nb, Ta and rare earth elements, the content of Al In the metal solution is h atom%, and the content of the element N1 In the metal solution is i atom%, When the content of the element N2 in the metal solution is j atom%, and the content of the element N3 in the metal solution is k atom%, h, i, j and k respectively satisfy 12.5-h < 95, 0-i < 71, 5-j < 40, and 0-k < 20.
59. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by comprising forming a negative electrode material having the following general formula (9): x xT1yJz… … (9) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein X is at least two elements selected from Al, Si, Mg, Sn, Ge, In, Pb, P and C, and T is1 is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, and x, y and z satisfy x + y + z of 100 atomic%, x is 50 or less and is 90 or less, y is 10 or less and is 33 or less, and z is 0 or less and is 10 or less, respectively.
60. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by comprising forming a negative electrode material having the following general formula (10) by a single-roll method: a1aT1bJcZd… … (10) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein A1 is at least one element selected from the group consisting of Si, Mg and Al, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, a, b, C and d satisfy a + b + C + d 100 atomic%, a is 50. ltoreq. 95, b is 5. ltoreq. 40, C is 0. ltoreq. 10 and d is 0. ltoreq. d < 20.
61. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by comprising forming a negative electrode material having the following general formula (11): tl100-a-b-c(A21-xJ’x)aBbJc… … (11) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, A2 is at least one element selected from the group consisting of Al and Si, J is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, J' is at least one element selected from the group consisting of C, Ge, Pb, P, Sn and Mg, a, b, C and x are each 10 atom% or more and 85 atom% or less, 0 < b or less and 35 atom% or less, 0 < C or less and 10 atom% or less, 0 < x or less and 0.3 or less, and the content of Sn is less than 20 atom% (includingContaining O atom%).
62. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by comprising forming a negative electrode material having the following general formula (12) by a single-roll method: (Mg)1-xA3x)100-a-b-c-d(RE)aT1bM1cA4d… … (12) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein A3 is at least one element selected from the group consisting of Al, Si and Ge, RE is at least one element selected from the group consisting of Y and rare earth elements, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr and Mn, M1 is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, A4 is at least one element selected from the group consisting of Sn, Pb, Zn, P and C, a, b, C, d and x are each 0 < a < 40 at%, 0 < b < 40 at%, 0 < C < 10 at%, 0 < d < 20 at%, and 0 < x < 0.5.
63. A method for producing a negative electrode material for a nonaqueous electrolyte battery, characterized by comprising forming a negative electrode material having the following general formula (13) by a single-roll method: (A11-xA5x)aT1bJcZd… … (13) to obtain an alloy substantially consisting of an amorphous phase, and heat-treating the alloy at a temperature equal to or higher than the crystallization temperature of the alloy; wherein A5 is at least one element selected from the group consisting of Si and Mg, T1 is at least one element selected from the group consisting of Fe, Co, Ni, Cr and Mn, J is at least one element selected from the group consisting of Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W and rare earth elements, Z is at least one element selected from the group consisting of C, Ge, Pb, P and Sn, and a, b, C, d and x satisfy a + b + C + d as 100 atomic%, a is 50. ltoreq. a.ltoreq.95, b is 5. ltoreq.40, C is 0. ltoreq. 10, d is 0. ltoreq. 20, and x is 0. ltoreq. 0.9.
CN02147000A 2001-09-28 2002-09-28 Negative electrode material for nonelectrolyte cell and making method, negative electrode and cell Pending CN1419303A (en)

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