JPH0729604A - Non-aqueous secondary battery - Google Patents

Abstract

PURPOSE:To provide a non-aqueous secondary battery having a high electric discharging operating voltage, a large electric discharging capacity, an excellent electric charging/discharging cycle characteristic, and high safety. CONSTITUTION:A non-aqueous secondary battery is composed of a negative electrode active material composed of a transition metal chalcogenide, which may include lithium, a positive electrode active material, and an organic electrolyte including lithium salt. An average particle diameter of the negative electrode active material is set to 0.2-30mum, and a specific surface area thereof is set to 0.1-5m<2>/g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous secondary battery having improved charge / discharge characteristics such as discharge potential, discharge capacity and charge / discharge cycle life and safety. The use of the battery according to the present invention is not particularly limited, for example, a portable personal computer, a pen input personal computer, a portable word processor, an electronic book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile facsimile, Portable copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, electric shaver, electronic translator, mobile phone, specified low power transceiver, power tool, electronic organizer, calculator, memory card,
It can be used for electronic tape recorders, watches, cameras, hearing aids, etc.

[0002]

2. Description of the Related Art Lithium metal and lithium alloys are typically used as a negative electrode active material for non-aqueous secondary batteries. When they are used, lithium metal grows in a dendritic form during charge / discharge, causing internal short circuit. , The activity of the dendritic metal itself is high,
There is a risk of ignition. On the other hand, recently, a baked carbonaceous material capable of inserting and extracting lithium has been put into practical use. This carbonaceous material is excellent in that the risk of ignition is relatively low and the charge / discharge capacity is high. However, the disadvantage is that lithium metal is deposited on the carbonaceous material at the time of overcharging or rapid charging because it itself has conductivity, and eventually there is a problem that dendritic metal is deposited. . In order to avoid this, we have devised a charger or adopted a method of reducing the amount of positive electrode active material to prevent overcharge.
In the latter method, the amount of active material is limited, so the discharge capacity is also limited. Further, since the carbonaceous material has a relatively low density, the discharge capacity per volume is small. Therefore, the discharge capacity is limited in terms of both the limitation of the amount of active material and the small capacity per volume.

On the other hand, as negative electrode active materials other than lithium metal, lithium alloys and carbonaceous materials, TiS ₂ and LiTiS capable of inserting and extracting lithium ions.
₂ (US Pat. No. 3,983,476), WO _{2 having} a rutile structure (US Pat. No. 4,198,476), Lix F.
Spinel compounds such as e (Fe ₂ ) O ₄ (JP-A-58-58)
220362), electrochemically synthesized Fe ₂
Lithium compound of O ₃ (US Pat. No. 4,464,447
No.), a lithium compound of Fe ₂ O ₃ (JP-A-3-112)
070), Nb ₂ O ₅ (Japanese Patent Publication No. 62-59412).
No. 2, JP-A-2-82447), iron oxide, Fe
O, Fe ₂ O ₃ , Fe ₃ O ₄ , cobalt oxide, CoO,
Co ₂ O ₃ and Co ₃ O ₄ (JP-A-3-291862) are known. Since all of these compounds have high redox potential, even if these compounds are used,
It is not possible to obtain a non-aqueous secondary battery having characteristics such as high discharge potential of 3 V class and high discharge capacity.

A positive electrode active material that is a metal chalcogenide and a negative electrode
As a combination with a polar active material, TiS ₂And LiTiS
₂(US Pat. No. 983,476), chemically synthesized
Li_{0. 1}V₂O_FiveAnd LiMn₁-s Mes O₂(0.1
<S <1, Me = transition metal; JP-A-63-210028
No.), chemically synthesized Li_0.1V₂O_FiveAnd Li
Co₁-s Fes O₂(S = 0.05 to 0.3; Japanese Patent Laid-Open No. Sho 6)
3-211564), chemically synthesized Li
_0.1V₂O_FiveAnd LiCo₁-s Nis O₂(S = 0.5 ~
0.9; JP-A-1-294364), V₂O_FiveWhen
Nb₂O_Five+ Lithium metal (JP-A-2-82447)
Report), V₂O_FiveAnd TiS₂And electrochemically synthesized L
ix Fe₂O₃(U.S. Pat. No. 4,464,447; J
Journal of Power Sources, Vol. 8, 289, 198
2 years), LiNix Co as positive electrode active material and negative electrode active material₁-x
O₂(0 ≦ x <1; JP-A-1-120765;
In the detailed description, the positive electrode active material and the negative electrode active material are the same from the examples.
It is described as a compound. ), LiCoO₂Or L
iMn₂O_FourAnd iron oxide, FeO, Fe₂O₃, Fe₃O
_Four, Cobalt oxide, CoO, Co₂O₃Or Co₃
O_Four(Japanese Patent Laid-Open No. 3-291862) and the like are known.
There is. However, any combination of these non-aqueous solutions
The secondary battery also has a discharge potential lower than 3V and is
However, it is not high enough.

Lix Fe ₂ O synthesized by electrochemically inserting lithium ions into the above transition metal
₃ (Journal of Power Sources, Volume 8, 289 pages,
(1982), it is described that the X-ray diffraction pattern changes due to the insertion of lithium ions, but the X-ray diffraction pattern also changes during charging and discharging. For this reason, the capacity decreases during charge and discharge, the discharge potential is low, and the life of the charge and discharge cycle becomes short. In addition, the above-mentioned JP-A-58-
In JP-A-220362, when lithium ions are inserted into a spinel compound such as Lix Mn ₂ O ₄ , the spinel structure is inserted so as not to be destroyed, and charging / discharging is performed so as not to change the structure. It is described that if lithium ions are excessively inserted into the spinel structure to destroy the spinel structure, the spinel compound will deteriorate in characteristics as an active material of a secondary battery.

As described above, it is not preferable that the crystal structure of the compound is changed or destroyed by repeated charging / discharging, so that there is almost no change in the crystal structure due to repeated charging / discharging, and the lithium ion insertion is largely restricted. A compound that does not exist is preferable as the negative electrode active material. Therefore, such a compound is required in order to obtain a non-aqueous secondary battery having the above-mentioned high discharge potential and high discharge capacity and having a small decrease in capacity during charge and discharge.

Under such circumstances, for example, Japanese Patent Application No. 5-12
No. 0,908, a transition metal oxide in which the basic structure of a crystal is changed by inserting lithium ions as a negative electrode active material, and the basic structure of the crystal after the change is in a state where the basic structure of the crystal does not change due to charge and discharge. A certain transition metal oxide (for example, a transition metal oxide before lithium ion insertion is Lia MOb (where M is at least one of Ti, V, Mn, Co, Fe, Ni, Cr, Nb, Mo).
Transition metal containing a, a = 0 to 3.1, b = 1.6 to 4.
A non-aqueous secondary battery using 1) etc. has been proposed. A battery using this transition metal oxide as a negative electrode active material has various advantages such as a high discharge potential and a high discharge capacity, good charge / discharge cycle characteristics, and high safety. However, if an attempt is made to put a non-aqueous secondary battery into practical use by using this negative electrode active material, the discharge capacity will be slightly insufficient, and its improvement is a major issue.

[0008]

The object of the present invention is to improve the discharge capacity of a non-aqueous secondary battery using a transition metal chalcogenide as a negative electrode active material, and to achieve high discharge potential and high discharge capacity. And to provide a safe non-aqueous secondary battery having excellent charge-discharge cycle characteristics.

[0009]

The object of the present invention is to use, as a negative electrode active material, a transition metal chalcogenide having an average particle size of 0.2 to 30 μm or a specific surface area of 0.1 to ⁵ m ² / g. It was achieved by a non-aqueous secondary battery characterized by being used.

As the negative electrode active material used in the present invention, one having an average particle size of 0.2 to 30 μm is selected and used. More preferably 0.3 to 20 μm, particularly preferably 0.5 to 1
Select and use the one of 5 μm. In the present invention, the average particle diameter is the mode diameter showing the most frequent point. Therefore, it can be measured using a laser diffraction type particle size distribution measuring device. The particle size distribution preferably has one peak, but may have two or more peaks. As the negative electrode active material used in the present invention, one having a specific surface area of 0.1 to ⁵ m ² / g is selected and used. More preferably 0.5 to ⁴ m ² / g, particularly preferably 2 m ² / g
More than 4 m ² / g less than 4 m ² / g is selected and used. In the present invention, the specific surface area can be measured by a commonly used BET one-point method. In the present invention, well-known crushers and classifiers are used to obtain particles having a predetermined particle size and specific surface area. For example, mortar, ball mill,
Vibratory ball mills, cone crushers, satellite ball mills, jet mills and sieves are used. The method for pulverizing the negative electrode active material used in the present invention is preferably a swirling airflow type jet mill (a method in which particles are collided with each other in a high-speed airflow to pulverize). The chemical formula of the compound obtained by the above calcination is measured by inductively coupled plasma (ICP).
As an emission spectral analysis method and a simple method, it was calculated from the weight difference between the powders before and after firing. It is considered that the positive electrode active material and the negative electrode active material used in the present invention obtained as described above are both compounds that occlude and release lithium ions and change the valence of the transition metal by charging and discharging. Therefore, the negative electrode active material of the present invention is a negative electrode active material having a concept that is fundamentally different from the method of depositing and dissolving lithium by charging and discharging, like a metal negative electrode active material such as lithium metal or lithium alloy. Also,
Similarly, when compared to carbonaceous compounds, carbon is not a compound that changes its valence clearly, and also has high conductivity,
It is a compound that easily deposits lithium metal during charging. Therefore, the negative electrode active material of the present invention is a negative electrode active material whose concept is fundamentally different from that of lithium metal or carbonaceous material.

The transition metal referred to in the present invention has an element number of 2.
From 1 of Sc to Zn of element number 30 and Y of element number 39 to Cd of element number 48 and La of element number 57 to Hg of element number 80. The chalcogenide referred to in the present invention is an oxygen group element, that is, oxygen, sulfur, selenium, tellurium, and polonium. The non-aqueous secondary battery of the present invention has a basic structure including a positive electrode active material, a negative electrode active material, and a non-aqueous electrolyte containing a lithium salt. The negative electrode active material is a transition metal chalcogenide which may contain lithium, or a lithium-containing transition metal chalcogenide obtained by inserting lithium ions therein (preferably electrochemically inserting it). When a battery is constructed using this negative electrode active material, a higher discharge voltage and a higher discharge capacity can be obtained when a lithium-containing transition metal oxide obtained by inserting lithium ions is used. Write down.

Insertion of lithium ions into the oxide of the transition metal, which may contain lithium, changes the basic structure of the crystal (the change in the basic structure of the oxide of the transition metal depends on the X-ray diffraction pattern). Of the lithium-containing transition metal oxide having lithium ions inserted thereinto until the basic structure of the changed crystal is substantially unchanged during charge / discharge (that is, X Until the line diffraction pattern is substantially unchanged). In the present invention, the change in the basic structure of the crystal means a change from a certain crystal structure to a different crystal structure, or a change from a certain crystal structure to an amorphous structure (a state having no crystal structure). The transition metal oxide before insertion of lithium ions (hereinafter referred to as a negative electrode active material precursor) used in the present invention is synthesized by mixing two or more kinds of transition metal compounds at a desired ratio, or one or two kinds with a lithium compound. It is preferable to synthesize at least one kind of transition metal compound so that the molar ratio of lithium compound / total transition metal compound is 3.1 or less. However, transition metals include Ti, V, Mn, Co, N
The transition metal contains at least one of i, Fe, Cr, Nb, and Mo. Further, the negative electrode active material precursor is preferably synthesized by mixing a lithium compound and a transition metal compound so that the molar ratio of lithium compound / total transition metal compound is 0.2 to 3.1. Here, the transition metal is
The transition metal contains at least one of Ti, V, Mn, Co, Ni and Fe.

At least one of the transition metal oxides which is the precursor of the negative electrode active material of the present invention is LipMOj (provided that M
Represents at least one transition metal and at least one of the transition metals is Ti, V, Mn, Co, Ni, F
e, Cr, Nb, and Mo, p is in the range of 0 to 3.1, and j is in the range of 1.6 to 4.1). The negative electrode active material precursor further comprises Lip M ₁ q1 M ₂ q2 ... Mnqn Oj
(However, each of M ₁ M ₂ ... Mn represents the transition metal, at least one of which is Ti, V, Mn, or C.
represents o, Ni or Fe, and p is 0 to 3.1.
, Q ₁ + q ₂ + ... + q n = 1 and
n ranges from 1 to 10 and j ranges from 1.6 to 4.1
In the range)) is preferred. Furthermore, in the above formula, p is in the range of 0.2 to 3.1 and n is 1 to 4
More preferably, and j is in the range of 1.8 to 4.1. In particular, in the above equation, p is 0.
Preferably, it is in the range 2-3.1, n is in the range 1-3, and j is in the range 1.8-4.1.

As described above, the negative electrode active material precursor of the present invention is a transition metal having stable valences of 5 to 6 (eg,
V, Cr, Nb, Mo) is preferably contained in order to obtain a high discharge capacity. From this viewpoint, as the negative electrode active material precursor of the present invention, at least V
It is particularly preferable to include

Examples of the negative electrode active material precursor containing V include:
Lip M₁q₁M₂q₂... Mnqn VqvOj (However, M is
It is a transition metal, p is in the range of 0 to 3.1, q₁
+ Q ₂+ ... + qn + qv = 1 and n is 1 to 9
Range, and j is in the range 1.3 to 4.1)
Is preferred. In addition, before the negative electrode active material containing V
The body is Lip Mq₁Mq₂V₁-(q₁+ q₂) Oj (However, M is
It is a transition metal, p is in the range of 0.2 to 3.1, and q
₁+ Q₂Is in the range 0 to 0.7, and j is 1.3
To 4.1)) is more preferable.
The negative electrode active material precursor containing V is Lip Coq.
V₁-q Oj, Lip Niq V₁-q Oj (where p is 0.
It is in the range of 3 to 2.2 and q is in the range of 0.02 to 0.7.
, And j is in the range 1.5-2.5)
Most preferably. Particularly preferred negative electrode active material in the present invention
As an example of the polymer precursor, Lip CoVO_FourAnd Lip NiV
O_Four(Where p is in the range of 0.3 to 2.2)
You can Here, the above p-value is before the start of charging / discharging.
Value, which increases or decreases depending on charge and discharge. Also, the negative electrode active material
Is the precursor composition formula with an increased lithium content.
In addition, the X-ray diffraction pattern is different from that of the negative electrode active material precursor.
They are qualitatively different. The general formula (eg, L
ip MOj), the total number of transition metals M is 1.
In case of multiple transition metals or in crystallographic composition formula, it is an integer
You may double.

The negative electrode active material of the present invention is obtained by inserting lithium ions into the above negative electrode active material precursor. Therefore,
The Lip of the transition metal oxide that may contain lithium as the negative electrode active material precursor is Lix. That is, x is generally in the range of 0.17 to 11.25 (the lithium increase x-p due to lithium ion insertion is generally 0.
The range is from 17 to 8.15). For example, a preferable negative electrode active material of the present invention, which is obtained by inserting lithium ions into Lip MOj of the preferable negative electrode active material precursor, is Lix MOj (where M represents at least one transition metal and At least one is Ti,
It is selected from V, Mn, Co, Fe, Ni, Nb and Mo, p is in the range of 0 to 3.1, and x is 0.
Is in the range 17-11.25, and j is 1.6-
It is composed of at least one lithium-containing transition metal oxide represented by (4. 1). x is preferably in the range of 0.26 to 10.2, and x is 0.3.
The range of 4 to 9.3 is preferable. Further, a preferable negative electrode active material is Lix Mq V ₁ -q Oj (where M represents a transition metal, p is in the range of 0 to 3.1, and x is 0.17 to
In the range 8.15, q in the range 0-0.7,
And j is in the range of 1.3 to 4.1).
x is preferably in the above range.

The negative electrode active material of the present invention can be obtained by inserting lithium ions into a negative electrode active material precursor of a transition metal oxide and / or a lithium-containing transition metal oxide as follows. For example, a method of reacting with lithium metal, a lithium alloy, butyl lithium, or the like, or a method of electrochemically inserting lithium ions is preferable. In the present invention, it is particularly preferable to electrochemically insert lithium ions into the transition metal oxide that is the negative electrode active material precursor. Above all, it is most preferable to use a lithium-containing transition metal oxide as a negative electrode active material precursor and electrochemically insert lithium ions into the transition metal oxide. As a method of electrochemically inserting lithium ions, a target lithium-containing transition metal oxide (a negative electrode active material precursor in the present invention) is included as a positive electrode active material, and lithium metal and a lithium salt are included as a negative electrode active material. It can be obtained by discharging a redox system composed of a non-aqueous electrolyte (for example, an open system (electrolysis) or a closed system (battery)). Furthermore, a redox system (for example, an open system) composed of a lithium-containing transition metal oxide as a positive electrode active material, a negative electrode active material precursor having a composition formula different from that of the positive electrode active material as a negative electrode active material, and a non-aqueous electrolyte containing a lithium salt. A method obtained by charging (electrolysis) or closed system (battery)) is preferable.

The amount of lithium ions inserted is not particularly limited, but is 27 to 1340 mA per 1 g of the negative electrode active material precursor.
h (corresponding to 1 to 50 mmol) is preferable. Especially 40 to 1
070 mAh (corresponding to 1.5 to 40 mmol) is preferable.
And 54-938 mAh (2-35 mmol equivalent) is the most preferable. The use ratio of the positive electrode active material and the negative electrode active material is not particularly limited, but it is preferable to set them so that the effective equivalents are equal to each other (the effective equivalent is an equivalent that can substantially maintain the cycle property). ). At that time, it is also preferable to increase the amount of either the positive electrode active material or the negative electrode active material. The cut-off voltage of the charge / discharge cycle cannot be uniquely determined because it changes depending on the type and combination of the positive electrode active material and the negative electrode active material used, but the voltage that can increase the discharge voltage and substantially maintain the cycleability. Is preferred.

The negative electrode active material thus obtained is one in which the basic structure of the crystal of this precursor has been changed, and this change is preferably from the diffraction angle (2θ) 5 of the X-ray diffraction pattern by CuKα rays. This is a change confirmed by changing the intensity of the X-ray diffraction maximum peak in the range of 70 degrees to ⅕ or less. Particularly, 1/10 or less is preferable, and 1/20 or less is most preferable. The intensity 0 here means that substantially all of the precursor of the negative electrode active material has changed to a negative electrode active material capable of charging and discharging, and specifically, noise of the X-ray diffraction pattern (baseline ) Level. Furthermore, it is preferable that at least one of the peaks other than the main peak disappears or a new peak is expressed.

The negative electrode active material thus obtained is generally a lithium-containing transition metal oxide, and the crystal thereof has a diffraction angle (2θ) of 5 to 70 degrees in an X-ray diffraction pattern by CuKα ray. It has a basic structure characterized by the intensity of all X-ray diffraction peaks within the range of 20 to 1000 cps. The peak intensity is preferably 20 to 800 cps, and further 20 to 5
00 cps is preferred, and 20-400 cps is most preferred. As the measurement conditions for the above X-ray diffraction, 40 k
V, 120 mA, scan speed = 32 ° / min. In addition, as a standard compound, the signal intensity of the main peak 2θ of LiCoO ₂ = 18.9 ° (4.691 A) was 7990 cps. (Synthesis method of LiCoO ₂ : Li ₂ CO ₃ and CoCO ₃ were mixed in a mortar so that Li / Co = 1 (molar ratio) and transferred to a magnetic crucible,
After left at 130 ° C. for 1 hour, it is baked in air at 900 ° C. for 6 hours. After cooling at 2 ° C./min, the mixture is ground in a mortar until the average particle size is about 7.5 μm in median diameter. The crystal form of the negative electrode active material is not a layered structure, a spinel structure or a rutile structure, but one having another crystal structure or one having no crystal structure.

Further, in the present invention, "the X-ray diffraction pattern of the negative electrode active material does not substantially change during charging / discharging" means that the crystalline or amorphous material expands and contracts due to the absorption and desorption of lithium ions. It means that the bond distance and the morphology of the particles change, but the basic crystalline or amorphous structure does not change. Specifically, during charging / discharging, the variation range of the lattice (plane) spacing obtained from the peak value of the X-ray diffraction method is preferably −0.1 to 0.1 A, and further −0.
05-0.05A is preferable. Further, the peak intensity ratio and the half width may vary.

As described above, the X-ray diffraction pattern of the negative electrode active material in which the lithium ions of the present invention are inserted does not substantially change even after repeated charging and discharging. For example, the negative electrode active material precursor LiCoVO ₄ is V ₅ + (Li ⁺ Co ²⁺ ) O
_The inverse spinel structure represented by ₄ changes the crystal structure when lithium ions are electrochemically inserted into this oxide, and becomes an unknown crystal structure or amorphous structure that gives a broad peak around 2 angstroms. change. This once-changed crystal structure or amorphous structure does not substantially change even if charging and discharging are repeated. This means that, as described in Japanese Patent Laid-Open No. 58-220362, "If too many lithium ions are inserted into the spinel structure, the spinel structure is destroyed and an unknown compound is formed. It is completely opposite to the conventional knowledge that "it is not preferable." Since the compound having this new structure has a low redox potential, it can be a negative electrode active material.

Examples of the negative electrode active material and the negative electrode active material precursor of the present invention include the following compounds, but the invention is not limited to these compounds. For example, TiS _2.0 , LiTi
_{S 2. 0, WO 2.0, Nb} 2.0 O 5.0, Co 3.0 O 4.0,
_{LiVO 3.1, LiTiO 2. 3, CoVO} 3.7, LiC
oVO _4.0 , LiCo _0.5 V _0.5 O _2.1 , LiNiVO
_4.0 , Li _0.75 Ni _0.5 V _0.5 O _2.1 , Li _1.75 Ni
_0.5 V _0.5 O _2.4 , LiTi _0.5 V _0.5 O _2.9 , LiM
_{n 0.5 V 0.5 O 2.5, LiFe} 0.5 Mn 0.5 O 2. 1, L
iCo _0.25 V _0.75 O _2.8 , LiNi _0.25 V _0.75 O _2.7 ,
_{LiNi 0.05 V 0. 95 O 3.1,} LiFe 0.05 V
_{0.95 O 3.1, LiMn 0.05 V 0.95} O 3.0, LiCa 0. 05
V _0.95 O _3.2 , LiCo _0.75 V _0.25 O _1.9 , LiMn
_{0.25 Ti 0.5 V 0.25 O 2. 6} , LiCr 0.05 V
_0.95 O _3.2 , LiNb _0.05 V _0.95 O _3.1 , LiMo _0.05
V _0. is a ₉₅ O _3.0. The oxygen number is a value obtained from the weight of the compound before firing and the weight after firing. Therefore, it is necessary to add an error of -10 to 10% of the above value to the oxygen number in view of the accuracy of the measuring method.

The positive electrode active material used in the present invention may be a transition metal oxide capable of reversibly occluding and releasing lithium ions, but a lithium-containing transition metal oxide is preferable. Preferred lithium-containing transition metal oxide positive electrode active materials include lithium-containing Ti, V, Cr, Mn, Fe and Co.
The oxide containing Ni, Cu, Mo and / or W can be mentioned. It is preferable that the positive electrode active material and the negative electrode active material have different composition formulas. The lithium-containing transition metal oxide that is the positive electrode active material of the present invention contains a lithium compound and one or more transition metal compounds in a lithium compound / total transition metal compound molar ratio of 0.3 to 2.2. It is preferable that they are mixed so as to be synthesized (however, the transition metal is at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Mo and W). Further, the transition metal is preferably at least one selected from V, Cr, Mn, Fe, Co and Ni.

The above-mentioned lithium-containing transition metal oxide, which is the positive electrode active material of the present invention, is Liy MOz (where M is Co,
A transition metal containing at least one selected from Mn, Ni, V and Fe, y is in the range of 0.3 to 1.2, and z is in the range of 1.4 to 3).

Preferred Lithium-Containing Metal Oxides of the Present Invention
As a positive electrode active material of Liy CoO₂, Liy NiO
₂, Liy Coa Ni₁-a O₂, Liy Cob V₁-b O
z, Liy Cob Fe₁-b O₂, Liy Mn₂O_Four, L
iy Mnc Co₂-c O_Four, Liy Mnc Ni₂-c O_Four,
Liy Mnc V₂-c O_FourAnd Liy Mnc Fe₂-c
O _Four, And Liy Mn₂O_FourAnd MnO₂Mixture with,
Li₂yMn₂O₃And MnO ₂Mixture with, and Liy M
n₂O_Four, Li₂yMn₂O₃And MnO₂Mixture with
, Y is in the range of 0.5 to 1.2, and a is 0.1 to
Is in the range of 0.9 and b is in the range of 0.8 to 0.98.
, C is in the range 1.6 to 1.96, and z is
2.01 to 5).

More preferred positive electrode active materials for lithium-containing metal oxides of the present invention include LiyCoO ₂ and Liy N.
iO ₂ , Liy Coa Ni ₁ -a O ₂ , Liy Cob V _1-
b Oz, Liy Cob Fe ₁ -b O ₂ , Liy Mn
₂ O ₄ , Liy Mnc Co ₂ -c O ₄ , Liy Mnc Ni ₂
-c O ₄ , Liy Mnc V ₂ -c O ₄ , Liy Mnc Fe ₂
-cO ₄ (however, y is in the range of 0.7 to 1.04, a
Is in the range of 0.1 to 0.9, and b is 0.8 to 0.98.
, C is in the range 1.6 to 1.96, and z is in the range 2.01 to 2.3). The most preferable lithium-containing transition metal oxides of the present invention include Liy CoO ₂ and Liy Ni.
O ₂ , Liy Coa Ni ₁ -a O ₂ , Liy Mn ₂ O ₄ ,
LiyCob V ₁ -b Oz (where y is in the range of 0.7 to 1.1, a is in the range of 0.1 to 0.9, b is in the range of 0.9 to 0.98) , And z is 2.01
(In the range of 2.3). further,
y is in the range of 0.7 to 1.04, and a is 0.1 to 0.
9, b is in the range of 0.9 to 0.98,
And z is preferably in the range of 2.02 to 2.3. Here, the above-mentioned y value is a value before the start of charging / discharging, and increases / decreases due to charging / discharging. The oxide of the positive electrode active material used in the present invention may be crystalline or amorphous, but a crystalline compound is preferable.

In the present invention, "the positive electrode active material and the negative electrode active material have different composition formulas" means the following: Different combinations of metal elements, and 2. Positive electrode active material Liy Cob V ₁ -b Oz and negative electrode active material L
The example of ix Coq V ₁ -q Oj means that the values of y and x, b and q, and z and j are not equal at the same time. In particular, this means that b and q and z and j are not equal at the same time. The positive electrode active material and the negative electrode active material used in the present invention are preferably combined with compounds having different standard redox potentials. The positive electrode active material of the present invention is a method of chemically inserting lithium ions into a transition metal oxide, a method of electrochemically inserting lithium ions into a transition metal oxide, or a method in which a lithium compound and a transition metal compound are mixed and fired. Can be synthesized by. When synthesizing the positive electrode active material of the present invention, as a method of inserting lithium ions into the transition metal oxide, a method of reacting lithium metal, a lithium alloy or butyllithium with the transition metal oxide is preferable. The positive electrode active material used in the present invention is particularly preferably synthesized by mixing a lithium compound and a transition metal compound and firing.

The negative electrode active material precursor of the present invention can also be synthesized by a method of mixing and firing a lithium compound and a transition metal compound or by a solution reaction, but a firing method is particularly preferable. The firing temperature used in the present invention may be a temperature at which a part of the mixed compound used in the present invention is decomposed and melted, and for example, 250 to 2000 ° C is preferable,
Particularly, 350 to 1500 ° C. is preferable. The firing gas atmosphere used in the present invention is not particularly limited, but the positive electrode active material is in air or in a gas containing a large proportion of oxygen (for example,
It is preferable that the negative electrode active material is in the air or a gas having a low oxygen content (for example, about 10% or less) or an inert gas (nitrogen gas, argon gas). Further, for example, when a lithium compound, a vanadium compound or a cobalt compound is mixed and fired, LiVO ₃ or Li ₃
VO ₄ may be generated. As described above, a compound having a low activity as a negative electrode active material precursor may be included in the synthesis process. Although such compounds may be included,
It may be removed if desired. The negative electrode active material precursor and the positive electrode active material of the present invention are preferably synthesized by firing a mixture of a lithium compound and a transition metal compound described below. Examples of the lithium compound include oxygen compounds, oxyacid salts and halides. As the transition metal compound, a monovalent to hexavalent transition metal oxide, the same transition metal salt, or the same transition metal complex salt is used.

Preferred lithium compounds that can be used in the present invention include lithium oxide, lithium hydroxide, lithium carbonate, lithium nitrate, lithium sulfate, lithium sulfite, lithium phosphate, lithium tetraborate, lithium chlorate and perchloric acid. Lithium, lithium thiocyanate,
Lithium formate, lithium acetate, lithium oxalate, lithium citrate, lithium lactate, lithium tartrate, lithium pyruvate, lithium trifluoromethanesulfonate, lithium tetraborate, lithium hexafluorophosphate, lithium fluoride, lithium chloride, bromide Examples thereof include lithium and lithium iodide.

Preferred transitions that can be used in the present invention
As a metal transfer compound, TiO₂, Lithium titanate,
Acetylacetonato titanyl, titanium tetrachloride, tetraiodide
Tan, titanyl ammonium oxalate, VOd (d = 2
2.5 d = 2.5 compound is vanadium pentoxide), V
Lithium compound of Od, vanadium hydroxide, metavanadi
Ammonium phosphate, ammonium orthovanadate, pi
Ammonium robanadate, vanadium oxosulfate, o
Vanadium trichloride, vanadium tetrachloride, lithium chromate
Tium, ammonium chromate, cobalt chromate, black
Rom acetylacetonate, MnO₂, Mn₂O₃,water
Manganese oxide, manganese carbonate, manganese nitrate, man sulfate
Cancer, ammonium manganese sulfate, manganese sulfite, phosphorus
Manganese acid, manganese borate, manganese chlorate, perchlorine
Manganese acid, manganese thiocyanate, manganese formate, vinegar
Manganese acid, manganese oxalate, manganese citrate, lactate
Gangan, manganese tartrate, manganese stearate, fluorinated
Manganese, manganese chloride, manganese bromide, manganese iodide
Iron, manganese acetylacetonate, iron oxide (2, 3
Value), ferric oxide, iron hydroxide (2, 3 value), iron chloride
(2,3 valence), iron bromide (2,3 valence), iron iodide (2,3 valence)
Value), iron sulfate (2,3 value), ammonium iron sulfate (2,3)
Trivalent), iron nitrate (2,3 valent) iron phosphate (2,3 valent), persalt
Iron oxide, iron chlorate, iron acetate (2,3 valent), iron citrate
(2,3 valence), ammonium iron citrate (2,3 valence),
Iron oxalate (2,3 valent), ammonium iron oxalate (2,3)
Value), CoO, Co₂O₃, Co₃O_Four, LiCo
O₂, Cobalt carbonate, basic cobalt carbonate, coba hydroxide
Rut, cobalt sulfate, cobalt nitrate, cobalt sulfite,
Cobalt perchlorate, cobalt thiocyanate, cobalt oxalate
Tobacco, cobalt acetate, cobalt fluoride, cobalt chloride, bromide
Cobalt, cobalt iodide, hexammine cobalt complex salt
(As salts, sulfuric acid, nitric acid, perchloric acid, thiocyanic acid, oxalic
Acid, acetic acid, fluorine, chlorine, bromine, iodine), nickel oxide,
Nickel hydroxide, nickel carbonate, basic nickel carbonate,
Nickel sulfate, nickel nitrate, nickel fluoride, nickel chloride
Gel, nickel bromide, nickel iodide, nickel formate, vinegar
Nickel acid salt, nickel acetylacetonate, copper oxide
(1, 2 valent), copper hydroxide, copper sulfate, copper nitrate, copper phosphate, fluorine
Copper oxide, copper chloride, ammonium chloride copper, copper bromide, copper iodide,
Copper formate, copper acetate, copper oxalate, copper citrate, nitric oxychloride
Bu, niobium pentachloride, niobium pentaiodide, niobium monoxide, diacid
Niobium oxide, niobium trioxide, niobium pentoxide, niobium oxalate,
Niobium methoxide, niobium ethoxide, niobium propoxide
Sid, niobium butoxide, lithium niobate, Mo
O₃, MoO₂, LiMo₂O_Four, Molybdenum pentachloride,
Ammonium molybdate, lithium molybdate, molybdenum
Ammonium ribdophosphate, molybdenum oxide acetylacetate
Tonato, WO ₂, WO₃, Tungstic acid, tangs
Ammonium tenate and Tungsto ammonium phosphate are listed.
You can get it.

Particularly preferred which can be used in the present invention
As a transition metal compound, TiO 2 ₂, Titanyl oxalate
Limonium, VOd (d = 2-2.5), VOd
Um compounds, ammonium metavanadate, MnO₂,
Mn₂O₃, Manganese hydroxide, manganese carbonate, man nitrate
Cancer, ammonium manganese sulfate, manganese acetate, oxalic acid
Manganese, manganese citrate, iron oxide (2,3 valent), four
Iron trioxide, iron hydroxide (2,3 valent), iron acetate (2,3)
Value), iron citrate (2,3 value), iron citrate ammoniu
(2,3 values), iron oxalate (2,3 values), iron oxalate ammonium
Um (2,3 valence), CoO, Co₂O₃, Co₃O_Four,
LiCoO₂, Cobalt carbonate, basic cobalt carbonate, water
Cobalt oxide, cobalt oxalate, cobalt acetate, nickel oxide
Gel, nickel hydroxide, nickel carbonate, basic nitric carbonate
Kell, nickel sulfate, nickel nitrate, nickel acetate, acid
Copper (1 and 2), copper hydroxide, copper acetate, copper citrate, M
oO₃, MoO₂, LiMo₂O_Four, WO₂, WO₃To
Can be mentioned.

Particularly preferred combinations of lithium compounds and transition metal compounds which can be used in the present invention are lithium oxide, lithium hydroxide, lithium carbonate, lithium acetate and VOd (d = 2 to 2.5), lithium of VOd. Compound, ammonium metavanadate, MnO ₂ , Mn ₂
O ₃ , manganese hydroxide, manganese carbonate, manganese nitrate iron oxide (2,3 valent), ferric tetroxide, iron hydroxide (2,3 valent)
Iron acetate (2,3 valent), iron citrate (2,3 valent), ammonium iron citrate (2,3 valent), iron oxalate (2,3 valent),
Ammonium iron oxalate (2,3 valent), CoO, Co
₂ O ₃ , Co ₃ O ₄ , LiCoO ₂ , cobalt carbonate, basic cobalt carbonate, cobalt hydroxide, cobalt sulfate, cobalt nitrate, nickel oxide, nickel hydroxide, nickel carbonate, basic nickel carbonate, nickel sulfate, nickel nitrate , Nickel acetate, MoO ₃ , MoO ₂ , LiMo ₂ O
₄ , WO ₃ can be mentioned.

In addition to lithium compounds and transition metal compounds,
In general, compounds that enhance ionic conductivity, such as Ca ₂ ⁺ (eg, calcium carbonate, calcium chloride, calcium oxide, calcium hydroxide, calcium sulfate, calcium nitrate, calcium acetate, calcium oxalate, calcium citrate, calcium phosphate). Alternatively, P, B, S
An amorphous former such as i (eg, P ₂ O ₅ , Li
₃ PO ₄ , H ₃ BO ₃ , SiO ₂ etc.) and the mixture may be fired. Further, alkali metal ions such as Na, K and Mg and / or Sn, Al, Ga, Ge, Ce,
You may mix with a compound containing In, Bi, etc. (for example, each oxide, hydroxide, carbonate, nitrate, etc.), and bake. Among them, calcium carbonate or P ₂ O ₅
It is preferable to mix with and fire. The addition amount is not particularly limited, but 0.2 to 10 mol% is preferable.

The average particle size of the positive electrode active material used in the present invention is not particularly limited, but is preferably 0.03 to 50 μm.

Materials that can be used with the negative electrode active material of the present invention include lithium metal and lithium alloys (Al, Al-
Mn (US Pat. No. 4,820,599), Al-Mg
(JP-A-57-98977), Al-Sn (JP-A-63-6742), Al-In, Al-Cd.
(JP-A-1-144573) or the like, or a calcined carbonaceous compound capable of occluding and releasing lithium ions or lithium metal (for example, JP-A-58-209864, JP-A-61-214417, JP-A-62-162). 88269, JP-A-62-216170, JP-A-63-
13282, JP 63-24555, JP 63-12147, and JP 63-1212.
57, JP-A-63-155568, JP-A-63-276873, and JP-A-63-314821.
JP, JP-A-1-204361, JP, 1-2
21859, JP-A-1-274360 and the like). The purpose of using the lithium metal or lithium alloy together is to insert lithium ions into the battery, and does not utilize the dissolution / precipitation reaction of lithium metal or the like as the battery reaction.

A conductive agent, a binder, a filler and the like can be added to the electrode mixture. The conductive agent may be any electron-conductive material that does not cause a chemical change in the constructed battery. Usually, natural graphite (scaly graphite, flake graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers and metals (copper, nickel, aluminum, silver (JP-A-63) -1
No. 48554), powders, metal fibers, or polyphenylene derivatives (Japanese Patent Laid-Open No. 59-20971) can be included as one kind or a mixture thereof. The combined use of graphite and acetylene black is particularly preferred. The amount added is not particularly limited, but is 1
-50% by weight is preferable, and 2-30% by weight is particularly preferable. For carbon and graphite, 2 to 15% by weight is particularly preferable.

As the binder, one or a mixture of polysaccharides, thermoplastic resins and polymers having rubber elasticity can be used. Preferred examples are starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose,
Diacetyl cellulose, polyvinyl chloride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, polybutadiene, fluororubber and polyethylene oxide. Can be mentioned. When a compound containing a functional group that reacts with lithium, such as a polysaccharide, is used, it is preferable to add a compound such as an isocyanate group to deactivate the functional group. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight, and particularly 2
-30% by weight is preferred. As the filler, any fibrous material that does not cause a chemical change in the constructed battery can be used. Generally, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. The amount of the filler added is not particularly limited, but is preferably 0 to 30% by weight.

The electrolyte is generally composed of a solvent and a lithium salt (anion and lithium cation) which is soluble in the solvent. As the solvent, propylene carbonate, ethylene carbonate, butylene carbonate,
Dimethyl carbonate, diethyl carbonate, γ-butyrolactone, methyl formate, methyl acetate, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, Ethyl monoglyme, phosphoric acid triester (JP-A-60-23973)
JP-A-61-4170.
JP-A-62-1577.
1, JP-A-62-22372, JP-A-62-62
-108474), sulfolane (JP-A-62-3)
1959), 3-methyl-2-oxazolidinone (JP-A-62-44961), propylene carbonate derivative (JP-A-62-290069, JP-A-6-290069).
2-290071), tetrahydrofuran derivative (JP-A-63-32872), ethyl ether (JP-A-63-62166), 1,3-propanesultone (JP-A-63-102173). Aprotic organic solvents such as, and these are used alone or in combination of two or more. Examples of the cation of a lithium salt that dissolves in these solvents include ClO
_{4 -, BF 4 -, PF} 6 -, CF3 SO 3 -, CF 3 C
O ₂ −, AsF ₆ −, SbF ₆ −, (CF ₃ SO ₂ ) ₂
N-, B ₁₀ Cl ₁₀₂ - (JP 57-74974 JP), (1,2-dimethoxyethane) ₂ ClO ₄ - (JP 57-74977 JP), lower aliphatic carboxylic acid ion (especially (Kaisho 60-41773), AlCl ₄
^{-, Cl -, Br -,} I - ( JP 60-247265
No.), an anion of a chloroborane compound (JP-A-61)
165957) and tetraphenyl borate ion (JP-A-61-214376).
These 1 type (s) or 2 or more types can be used.
Among them, propylene mosquitoes - BONNET - DOO or ethylene carbonate and 1,2-dimethoxyethane and / or LiCF ₃ SO ₃ in a mixture of diethyl carbonate, Li
An electrolyte containing ClO ₄ , LiBF ₇ and / or LiPF ₆ is preferred.

The amount of these electrolytes added to the battery is not particularly limited, but can be used in the required amount depending on the amount of the positive electrode active material or the negative electrode active material and the size of the battery. The volume ratio of the solvent is not particularly limited, but in the case of a mixed solution of propylene carbonate or ethylene capote and 1,2-dimethoxyethane and / or diethyl carbonate, 0.4 / 0.6 to 0.6 / 0.4. (The mixing ratio when both 1,2-dimethoxyethane and diethyl carbonate are used is 0.4 / 0.6 to 0.6 / 0.4). The concentration of the supporting electrolyte is not particularly limited, but is preferably 0.2 to 3 mol per liter of the electrolytic solution.

In addition to the electrolytic solution, the following solid electrolytes can be used. Solid electrolytes are classified into inorganic solid electrolytes and organic solid electrolytes. Li-nitrides, halides, oxyacid salts, and the like are well known as inorganic solid electrolytes. Among them, Li ₃ N, LiI, Li ₅ N
_{I 2, Li 3 N-LiI} -LiOH, LiSiO 4, L
iSiO ₄ -LiI-LiOH (JP-A-49-8189)
9 _{JP), xLi 3 PO 4 - (} 1-x) Li4 SiO
₄ (Japanese Patent Laid-Open No. 59-60866), Li ₂ SiS ₃
(JP-A-60-501731), phosphorus sulfide compounds (JP-A-62-82665) and the like are effective.

In the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative (JP-A-63-1).
35447), polypropylene oxide derivatives or polymers containing these derivatives, polymers containing ion dissociative groups (JP-A-62-254302, JP-A-6-254302).
2-254303, JP-A-63-193954), a mixture of a polymer containing an ion dissociative group and the aprotic electrolyte (US Pat. No. 4,792,504,
U.S. Pat. No. 4,830,939, JP-A-62-223
75, JP 62-22376, and JP 6
3-22375, JP-A-63-22776, JP-A-1-95117), a phosphoric acid ester polymer (JP-A-61-256573), and a polymer containing an aprotic polar solvent. Matrix material (US Pat. No. 4,822,70, US Pat. No. 4,83
0,939, JP-A-63-239779, Japanese Patent Application No. 2-30318, and Japanese Patent Application No. 2-78531) are effective. Furthermore, there is also a method of adding polyacrylonitrile to the electrolytic solution (JP-A-62-278774).
Issue). Further, a method of using an inorganic and organic solid electrolyte in combination (Japanese Patent Laid-Open No. 60-1768) is also known.

As the separator, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. A sheet or non-woven fabric made of olefin polymer such as polypropylene or glass fiber or polyethylene is used because of its resistance to organic solvent and hydrophobicity. The pore size of the separator is in the range generally used for batteries. For example, 0.01 to 10 μ
m is used. The thickness of the separator is generally within the range for batteries. For example, 5 to 300 μm is used.

Other compounds may be added to the electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine (JP-A-49-108525), triethylphosphite (JP-A-47-4376), triethanolamine (JP-A-52-72425), cyclic ether (JP-A-57-57425). 152684), ethylenediamine (JP-A-58-87777), n-glyme (JP-A-58-87778), hexaphosphoric acid triamide (JP-A-58-8777).
9), nitrobenzene derivatives (JP-A-58-21)
No. 4281), sulfur (JP-A-59-8280), quinone imine dye (JP-A-59-68184), N-substituted oxazolidinone and N, N'-substituted imidazolidinone (JP-A-59-154778). Gazette), ethylene glycol dialkyl ether (JP-A-59-20)
No. 5167), quaternary ammonium salts (Japanese Patent Laid-Open No. Sho 60).
-30065), polyethylene glycol (JP-A-60-41773), pyrrole (JP-A-60-).
79677), 2-methoxyethanol (JP-A-60-
89075), AlCl3 (JP-A-61-884).
No. 66), a monomer of a conductive polymer electrode active material (JP-A 61-161673), triethylene phosphoramide (JP-A 61-208758), trialkylphosphine (JP-A 62-80976). No.), morpholine (JP-A-62-80977),
Aryl compounds having a carbonyl group (JP-A-62-86)
No. 673), crown ethers such as 12-crown 4 (Physical Review)
B, 42, 6424 (1990)), hexamethylphosphoric triamide and 4-alkylmorpholine (JP 62-217575A), secondary tertiary amine (JP 62-217578A). , Oil (JP-A-62-287580), quaternary phosphonium salt (JP-A-63-1212268), tertiary sulfonium salt (JP-A-3-121269) and the like.

Further, in order to make the electrolytic solution nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolytic solution (JP-A-48-36,6).
32). Further, the electrolytic solution may contain carbon dioxide gas in order to have suitability for high temperature storage (JP-A-59-13).
4567). Further, the mixture of the positive electrode and the negative electrode can contain an electrolytic solution or an electrolyte. For example, the ion-conductive polymer or nitromethane (Japanese Patent Laid-Open No. 48-3
6633), electrolytic solution (JP-A-57-124870).
(Japanese Patent Publication) is known. Further, the surface of the positive electrode active material can be modified. For example, the surface of a metal oxide is treated with an esterifying agent (JP-A-55-16).
3779) or treatment with a chelating agent (JP-A-55-163780), conductive polymer (JP-A-5-163).
No. 8-163188, No. 59-14274), polyethylene oxide, etc. (JP-A-60-97).
No. 561). Also, the surface of the negative electrode active material can be modified. For example, an ion conductive polymer or polyacetylene layer is provided (JP-A-58-111276), or LiC
1 (JP-A-58-142771) and the like.

The collector of the electrode active material may be any electron conductor as long as it does not undergo a chemical change in the constructed battery. For example, for the positive electrode, in addition to stainless steel, nickel, aluminum, titanium, calcined carbon, etc. as the material, carbon on the surface of aluminum or stainless steel,
Those treated with nickel, titanium or silver, and the negative electrode are made of stainless steel, nickel, copper, titanium,
In addition to aluminum and calcined carbon, copper, stainless steel whose surface is treated with carbon, nickel, titanium, or silver), an Al-Cd alloy, or the like is used. It is also used to oxidize the surface of these materials. The shape is
In addition to the foil, a film, a sheet, a net, a punched product, a lath body, a porous body, a foamed body, a molded body of a fiber group and the like are used. The thickness is not particularly limited, but is 1 to 5
Those having a diameter of 00 μm are used.

The shape of the battery can be any of coins, buttons, sheets, cylinders, corners and the like. When the shape of the battery is a coin or a button, the mixture of the positive electrode active material and the negative electrode active material is used by being compressed into a pellet shape. The thickness and diameter of the pellet are determined by the size of the battery. Further, when the shape of the battery is a sheet, a cylinder, or a corner, the mixture of the positive electrode active material and the negative electrode active material is applied (coated) on the current collector, dried and compressed, and is mainly used. As a coating method, a general method can be used. Examples thereof include a reverse roll method, a direct roll method, a blade method, a knife method, an extrusion method, a curtain method, a gravure method, a bar method, a dip method and a squeeze method. The blade method, knife method and extrusion method are preferred. The coating is preferably carried out at a speed of 0.1 to 100 m / min. At this time, a good surface condition of the coating layer can be obtained by selecting the above-mentioned coating method according to the solution physical properties and drying properties of the mixture. The thickness, length and width of the coating layer are determined by the size of the battery, but the thickness of the coating layer is particularly preferably 1 to 2000 μm in a compressed state after drying.

As a method for drying or dehydrating the pellets or sheets, a generally adopted method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far infrared rays, electron beams, and low humidity air alone or in combination. The temperature is preferably in the range of 80 to 350 ° C, particularly 10
The range of 0 to 250 ° C. is preferable. The water content of the whole battery is preferably 2000 ppm or less, and the content of each of the positive electrode mixture, the negative electrode mixture and the electrolyte is preferably 500 ppm or less from the viewpoint of cycleability. As a pellet or sheet pressing method, a generally adopted method can be used, but a die pressing method or a calendar pressing method is particularly preferable. The pressing pressure is not particularly limited, but is 0.2 to 3 t /
m ² is preferred. The press speed of the calendar press method is
0.1 to 50 m / min is preferable. Press temperature is room temperature ~
200 ° C. is preferred.

The mixture sheet is rolled or folded and inserted into a can, the can and the sheet are electrically connected, an electrolytic solution is injected, and a sealing plate is used to form a battery can. At this time, the safety valve can be used as a sealing plate. Other than safety valve,
Various conventionally known safety elements may be provided. For example, a fuse, a bimetal, a PTC element or the like is used as the overcurrent prevention element. In addition to the safety valve, a method of making a notch in the battery can, a method of cracking a gasket, or a method of cracking a sealing plate can be used as a measure for increasing the internal pressure of the battery can. Further, the charger may be provided with a circuit incorporating measures against overcharge and overdischarge. For the can and the lead plate, a metal or alloy having electrical conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper and aluminum or alloys thereof are used. As a method for welding the cap, the can, the sheet, and the lead plate, a known method (eg, DC or AC electric welding, laser welding, ultrasonic welding) can be used. As the sealing agent for sealing, a conventionally known compound or mixture such as asphalt can be used.

[0050]

EXAMPLES The present invention will be described in more detail with reference to specific examples below, but the present invention is not limited to the examples as long as the gist of the invention is not exceeded. Example 1 The negative electrode and the positive electrode active material shown in Tables 1 and 2 are respectively the negative electrode active material (z value is the value of the fired sample obtained by the above-mentioned simple method). Li _0.5 Co _0.5 V _0.5 O _2.0 (calcination of lithium carbonate, cobalt oxide, and vanadium pentoxide in air at 800 ° C. for 6 hours) B. Li _1.0 Co _0.5 .5 V _0.5 O _2.0 (Lithium carbonate, cobalt carbonate and ammonium metavananoate 8
Calcination at 00 ° C. for 6 hours) Positive electrode active material (z value is the value of the calcined sample obtained by the simple method) LiCoO ₂ (calcined lithium carbonate and cobalt carbonate in air at 900 ° C. for 6 hours) b. LiCo _0.95 V _0.05 O _2.0 (900% lithium carbonate, cobalt carbonate and ammonium metavanadate in air
Calcination for 6 hours).

Next, each of the negative electrode active materials A and B was subjected to an average particle size (1) using a swirling airflow type jet mill.
0.1 μm, (2) 0.2 μm, (3) 0.3 μm,
(4) 0.5 μm, (5) 1 μm, (6) 10 μm,
(7) 15 μm, (8) 20 μm, (9) 30 μm,
(10) An active material of 50 μm was obtained. A laser diffraction particle size distribution analyzer LA-500 manufactured by Horiba, Ltd. was used to measure the average particle size.

As a method of preparing the mixture, in the negative electrode material, the negative electrode active material precursor was 82% by weight, the scaly graphite was 12% by weight as the conductive agent, and the polyvinylidene fluoride was 6% by weight as the binder. The negative electrode pellet (15 mmΦ, 0.12 g) obtained by compression-molding the mixture mixed at the mixing ratio was thoroughly dehydrated with a far infrared heater in a dry box (dew point −40 to −70 ° C., dry air) before use. In the positive electrode material, 82% by weight of the positive electrode active material, 12% by weight of flake graphite as a conductive agent, and 6% by weight of tetrafluoroethylene as a binder.
The positive electrode pellet (15 mmΦ, 0.6 g) obtained by compression-molding the mixture mixed at the mixing ratio of was thoroughly dehydrated with a far infrared heater in the same dry box as above and used. As a current collector, a SUS316 net having a thickness of 80 μm was welded to a coin can for both the positive and negative electrode cans. 1 mol as electrolyte
/ Liter LiPF ₆ (equal volume mixture of ethylene carbonate and diethylene carbonate) was used in an amount of 250 μl, and a microporous polypropylene sheet and a polypropylene non-woven fabric were used as a separator to impregnate the non-woven fabric with the electrolytic solution. Using. Then, a coin type lithium battery as shown in FIG. 1 was produced in the same dry box as above. Test 1. This lithium battery was subjected to a charge / discharge test at a current density of 1 mA / cm ² , and the number of cycles until the capacity reached 60% of the maximum capacity was determined. Test 2. This lithium battery was subjected to a 100% depth (3.9 V to 1.8 V) charge / discharge test at a current density of 1 mA / cm ² , and the discharge capacity at the 10th cycle was determined. All tests started with charging.

[0053]

[Table 1]

[0054]

[Table 2]

Example 2 A test was conducted in the same manner as in Example 1 except that an electrode mixture was dissolved in a solvent, coated on a metal foil by a blade method, punched to 15 mmΦ and then pressed to form an electrode.

[0056]

[Table 3]

[0057]

[Table 4]

Example 3 Negative electrode active materials A and B were each subjected to a specific surface area (1) 0.05 m ^{2 /} g, ( ² ) 0.1 using a swirling airflow type jet mill.
^{m 2 /g,(3)0.5m 2 / g, (} 4) 1m 2 / g, (5)
2m ² / g, (6) 3m ² / g, (7) 4m ² / g, (8) 5
m ² / g, (9) 6 m ² / g of active material was obtained. The specific surface area was measured using nitrogen gas, using Cantasorb manufactured by Cantachrome. A test was conducted in the same manner as in Example 2 except that the above active material was used.

[0059]

[Table 5]

[0060]

[Table 6]

As a result of Examples 1, 2 and 3, it was shown that the discharge voltage was high, the charge / discharge cycle was long, and the discharge capacity was particularly large with the particle diameter and specific surface area of the present invention. In addition, the pellet specific gravity of the lithium-containing transition metal oxide that is the negative electrode active material of the present invention is 2.5 to 2.8, and that of the calcined carbonaceous material is about twice that of 1.1 to 1.4. Big again
The negative electrode active material whose structure is changed by inserting lithium ions has a discharge capacity per unit weight that is about 2-3 times larger, and the discharge capacity per volume of the negative electrode active material of the present invention is 4 times that of the calcined carbonaceous material. It turns out that it will be about twice as big.

[0062]

INDUSTRIAL APPLICABILITY As in the present invention, in a non-aqueous secondary battery comprising a positive electrode active material, a negative electrode active material, and an organic electrolyte, the transition metal oxide as the negative electrode active material has an average particle size of 0.2 to 30 μm.
m and the specific surface area of 0.1 to 5 m ² / g improve the discharge capacity of the non-aqueous secondary battery, have a high discharge potential and a high discharge capacity, and have good charge-discharge cycle characteristics. A non-aqueous secondary battery can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a coin battery used in an example.

[Explanation of symbols]

 1 Negative Electrode Sealing Plate 2 Negative Electrode Mixture Pellet 3 Separator 4 Positive Electrode Mixture Pellet 5 Current Collector 6 Positive Electrode Case 7 Gasket

Claims (12)

[Claims] 1. A non-aqueous secondary battery comprising a positive electrode active material, a negative electrode active material and a non-aqueous electrolyte containing a lithium salt, wherein the negative electrode active material is a transition metal chalcogenide having an average particle size of 0.2 to 30 μm. A non-aqueous secondary battery characterized by being present. 2. A non-aqueous secondary battery comprising a positive electrode active material, a negative electrode active material, and a non-aqueous electrolyte containing a lithium salt, wherein the negative electrode active material is a sheet-shaped electrode. Non-aqueous secondary battery. 3. The average particle size of the negative electrode active material is 0.3 to 20.
The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery has a thickness of μm. 4. The average particle size of the negative electrode active material is 0.5 to 15.
The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery has a thickness of μm. 5. A non-aqueous secondary battery comprising a positive electrode active material, a negative electrode active material and a non-aqueous electrolyte containing a lithium salt, wherein the negative electrode active material is a transition metal having a specific surface area of 0.1 to ⁵ m ² / g. A non-aqueous secondary battery characterized by being a chalcogenide. 6. The non-aqueous secondary battery according to claim 5, wherein the negative electrode active material is a sheet electrode. 7. The specific surface area of the negative electrode active material is 0.5 to ⁴ m ^2.
It is / g, The non-aqueous secondary battery of Claim 5 or 6 characterized by the above-mentioned. 8. A nonaqueous secondary battery according to claim 5 or 6, wherein the specific surface area of the negative electrode active material is less than 4m ² / g to more than 2m ² / g. 9. The negative electrode active material comprises a transition metal oxide, according to any one of claims 1 to 4 or 5 to 8.
The non-aqueous secondary battery described in. 10. The negative electrode active material is a transition metal oxide in which the basic crystal structure is changed by inserting lithium ions, and the basic crystal structure after the change is in a state where the basic crystal structure does not change due to charge and discharge. The non-aqueous secondary battery according to claim 1, which is made of a certain transition metal oxide. 11. The negative electrode active material comprises Lia MOb (provided that
M is Ti, V, Mn, Co, Fe, Ni, Cr, Nb
And Mo represents at least one transition metal, a is in the range of 0 to 11.25, and b is 1.
The non-aqueous secondary battery according to any one of claims 1 to 4 or 5 to 8, which comprises a transition metal oxide represented by the formula (6 to 4.1). 12. The negative electrode active material is obtained by pulverization with a swirling airflow type jet mill.
11. The non-aqueous secondary battery according to item 11.