KR20160137449A - Positive active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same - Google Patents

Abstract

The present invention relates to a cathode active material for a lithium secondary battery, a manufacturing method thereof, and a lithium secondary battery comprising the same. The cathode active material for a lithium secondary battery according to the present invention comprises: a compound capable of reversible intercalation and deintercalation of lithium; and a coated layer located on at least a part of a surface of the compound. The coated layer includes Li3PO4, and is a complex coated layer additionally including a lithium metal oxide, a metal oxide, or a combination thereof, wherein at least one of the lithium metal oxide and the metal oxide includes metal M independent of each other. Metal M1 is an element selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, V and Zr, and includes a compound containing at least one element selected from metal M2 consisting of Ni, Co, and Mn separately from the compound capable of reversible intercalation and deintercalation of lithium. The cathode active material for a lithium secondary battery according to the present invention can have high capacity and high efficiency.

Description

TECHNICAL FIELD The present invention relates to a cathode active material for a lithium secondary battery, a method for producing the same, and a lithium secondary battery including the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

A cathode active material for a lithium secondary battery, a method for producing the same, and a lithium secondary battery comprising the same.

Recently, with regard to the tendency to miniaturize and lighten portable electronic devices, there is an increasing need for high performance and large capacity of batteries used as power sources for these devices.

Cells generate electricity by using materials that can electrochemically react to the positive and negative electrodes. A representative example of such a battery is a lithium secondary battery that generates electrical energy by a change in chemical potential when the lithium ions are intercalated / deintercalated in the positive electrode and the negative electrode.

The lithium secondary battery is manufactured by using a material capable of reversible intercalation / deintercalation of lithium ions as a positive electrode and a negative electrode active material, and filling an organic electrolyte or a polymer electrolyte between the positive electrode and the negative electrode.

As a cathode active material of a lithium secondary battery, a lithium composite metal compound is used. For example, composite metal oxides such as LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ and LiMnO ₂ have been studied.

Of the above cathode active materials, Mn-based cathode active materials such as LiMn ₂ O ₄ and LiMnO ₂ are easy to synthesize and are relatively inexpensive and have excellent thermal stability compared to other active materials in overcharging, However, it has a disadvantage of low capacity.

LiCoO ₂ is a typical cathode active material commercially available and commercially available since it has good electric conductivity, high battery voltage of about 3.7 V, excellent cycle life characteristics, stability and discharge capacity. However, since LiCoO ₂ is expensive, it accounts for more than 30% of the battery price, which causes the price competitiveness to deteriorate.

LiNiO ₂ also exhibits the highest discharge capacity of the battery among the above-mentioned cathode active materials, but it is difficult to synthesize LiNiO ₂ . Also, the high oxidation state of nickel causes degradation of battery life and electrode life, and there is a problem that self discharge is severe and reversibility is low. In addition, it is difficult to commercialize it because the stability is not completely secured.

As described above, there have been provided cathode active materials for lithium secondary batteries including various coating layers for improving battery characteristics in the prior art.

The present invention provides a positive electrode active material for lithium secondary batteries excellent in high capacity, high efficiency, and long life characteristics, and a lithium secondary battery including the positive electrode active material.

In one embodiment of the present invention, a first compound capable of reversible intercalation and deintercalation of lithium; And a second compound that is independent of the first compound and comprises at least one metal M2 of Ni, Co, and Mn, and that is located at least in part of a surface of the first compound, Wherein the coating layer comprises Li ₃ PO ₄ and the coating layer is a composite coating layer further comprising a lithium metal oxide, a metal oxide, or a combination thereof, wherein at least one of the lithium metal oxide and the metal oxide is a metal M, and the metal M1 is at least one element selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, And a positive electrode active material for a lithium secondary battery.

The Li ₃ PO ₄ contained in the composite coating layer or the lithium of the lithium metal oxide may originate from Li contained in the first compound capable of reversibly intercalating and deintercalating lithium, Lt; / RTI >

The second compound may be capable of reversible intercalation and deintercalation of lithium.

The second compound may include Co.

The second compound may be a Li-deficient compound (Li / M ratio < 1.0).

The composite coating layer may further include LiF.

The second compound may include a metal M and the metal M may be at least one element selected from the group consisting of Mg, Ni, Ti, Al, Si, Sn, Mn and Zr.

The P of Li ₃ PO ₄ contained in the composite coating layer can be attributed to the P compound provided separately.

The composite coating layer may further include MgF ₂ .

The lithium metal oxide included in the composite coating layer may be LiAlO ₂ , Li ₂ MgO ₂ , Li ₂ TiO ₃ , Li ₂ ZrO ₃ , Li ₂ SiO ₃ , Li ₄ SiO _4, or a combination thereof.

The metal oxide contained in the composite coating layer may be _{Al 2 O 3, MgO, TiO} 2, ZrO 2, SiO 2, or combinations thereof.

The first compound capable of reversible intercalation and deintercalation of lithium is Li _a A _{1 - b} X _b D ₂ (0.90? A? 1.8, 0? B? 0.5); Li _a A _{1 - b} X _b O _{2 - c} T _c (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05); LiE _{1 - b} X _b O _{2 - c} D _c (0? B? 0.5, 0? C? 0.05); LiE _2-b X _b O _4-c T _c (0? B? 0.5, 0? C? 0.05); Li _a Ni _{1 -b- c} Co _b X _c D _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2); Li _a Ni _{1 -b- c} Co _b X _c O _{2 - ?} T _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Co _b X _c O _{2 - ?} T ₂ (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _{1 -b- c} Mn _b X _c D _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2); Li _a Ni _{1 -b- c} Mn _b X _c O _{2 - ?} T _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _{1 -b- c} Mn _b X _c O _{2 - ?} T ₂ (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _b E _c G _d O _{2 -e} T _e (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1, 0 ≤ e ≤ 0.05); _{Li a Ni b Co c Mn d} G e O 2 - f T f (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1, 0 ≤ e ? 0.05); Li _a NiG _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a CoG _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a MnG ' _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a Mn ₂ G _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a MnG ' _b PO ₄ (0.90? A? 1.8, 0.001? B? 0.1); LiNiVO _4; And Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2).

In the above formula, A is selected from the group consisting of Ni, Co, Mn, and combinations thereof; X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and combinations thereof; D is selected from the group consisting of O, F, S, P, and combinations thereof; E is selected from the group consisting of Co, Mn, and combinations thereof; T is selected from the group consisting of F, S, P, and combinations thereof; G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof; Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof; J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

The content of the composite coating layer with respect to the total weight of the cathode active material may be 0.2 to 2.0 wt%.

The second compound may be contained in an amount of 1 to 5% by weight based on the total amount of the cathode active material.

In another embodiment of the present invention, there is provided a method of preparing a lithium secondary battery, comprising: preparing a first compound capable of reversible intercalation and deintercalation of lithium; A lithium source; Phosphorus source; Metal M source; And a separate metal M2 source; The lithium source to a first compound capable of reversible intercalation and deintercalation of lithium; Phosphorus source; Metal M source; And a separate source of metal M2 to provide a lithium source on the surface of the first compound capable of reversible intercalation and deintercalation of lithium; Phosphorus source; Metal M source; And a separate metal M2 source; And the lithium source; Phosphorus source; Metal M source; And a second compound capable of reversible intercalation and deintercalation of lithium to which a separate metal M2 source is attached is subjected to a heat treatment to form Li ₃ PO ₄ and a lithium metal oxide, a metal oxide, A first compound capable of reversibly intercalating and deintercalating lithium formed on the surface of the composite coating layer that further comprises at least one metal M2 of Ni, Co, and Mn, independently of the first compound, To obtain a cathode active material comprising a second compound,

Wherein the metal M comprises at least one selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, V and Zr, Wherein at least one of the oxide and the metal oxide comprises a metal M independently from each other. The present invention also provides a method for producing a cathode active material for a lithium secondary battery.

The lithium source; Phosphorus source; Metal M source; And a second compound capable of reversible intercalation and deintercalation of lithium to which a separate metal M2 source is attached are heat treated to form Li ₃ PO ₄ and a lithium metal oxide, a metal oxide, and / A first compound capable of reversible intercalation and deintercalation of lithium formed on the surface of the composite coating layer, and a first compound capable of reversibly intercalating and deintercalating lithium Independently obtaining a cathode active material comprising a second compound comprising at least one metal M2 of Ni, Co, and Mn; , The heat treatment temperature may be 650 to 950 캜.

According to another embodiment of the present invention, there is provided a positive electrode comprising a positive electrode active material for a lithium secondary battery according to an embodiment of the present invention; A negative electrode comprising a negative electrode active material; And an electrolyte; The present invention provides a lithium secondary battery comprising the same.

A positive electrode active material having excellent battery characteristics and a lithium secondary battery including the same can be provided.

1 is a schematic view of a lithium secondary battery.
2 is a scanning electron micrograph of Example 4. Fig.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

In one embodiment of the present invention, a first compound capable of reversible intercalation and deintercalation of lithium; And a second compound that is independent of the first compound and comprises at least one metal M2 of Ni, Co, and Mn, and that is located at least in part of a surface of the first compound, Wherein the coating layer comprises Li ₃ PO ₄ and the coating layer is a composite coating layer further comprising a lithium metal oxide, a metal oxide, or a combination thereof, wherein at least one of the lithium metal oxide and the metal oxide is a metal M, and the metal M1 is at least one element selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, And a positive electrode active material for a lithium secondary battery.

The compound in the composite coating layer may be a compound generated by a heat treatment reaction.

The Li ₃ PO ₄ contained in the composite coating layer or the lithium of the lithium metal oxide may originate from Li contained in the first compound capable of reversibly intercalating and deintercalating lithium, Or may be from a material.

The cathode active material comprising the first compound including the composite coating layer containing Li ₃ PO ₄ and further including a lithium metal oxide, a metal oxide, or a combination thereof can improve the battery characteristics of the lithium secondary battery . More specifically, it is possible to provide a cathode active material having an initial capacity higher than that of a conventional cathode active material, an improved efficiency characteristic, and excellent cell characteristics.

Further comprising a second compound comprising at least one metal M2 selected from Ni, Co, and Mn that is independent of the first compound capable of reversible intercalation and deintercalation of lithium, Can absorb the Li of the first compound capable of reversible intercalation and deintercalation of Li. From this, it is possible to control the impurity on the surface of the positive electrode active material.

Further, the surface crystal structure of the cathode active material can be rearranged to secure excellent battery characteristics.

The second compound can reversibly intercalate and deintercalate lithium. However, it is independent of the above-described first compound capable of reversible intercalation and deintercalation of lithium.

The second compound may be one containing Co. However, the present invention is not limited thereto.

The second compound may be a Li-deficient (Li / M ratio <1.0) cathode active material. Because of this property of the second compound as described above, it can assist the Li absorption function of the first compound.

The second compound may be a Li-deficient active material capable of reversible lithium intercalation and deintercalation by various Li sources through heat treatment.

The metal compound including Li in the composite coating layer can perform a driving force to enhance the diffusion of Li ions in the cathode active material. From this, it is possible to facilitate the movement of Li ions and to contribute to the improvement of battery characteristics.

More specifically, the composite coating layer causes a synergistic effect on the surface modification through complex bonding with each other on the surface of the cathode active material.

The above-mentioned Li ₃ PO ₄ also improves the ion conductivity and is effective in improving the efficiency.

The composite coating layer may further include LiF. When LiF is further included, it inhibits side reactions with the electrolyte, contributing to the stabilization of the surface structure, and is more advantageous in improving battery characteristics.

In addition, the cathode active material according to one embodiment of the present invention can improve the battery characteristics of the lithium secondary battery. Examples of improved battery characteristics include the initial capacity of the cell at high voltage characteristics, improved efficiency characteristics, and excellent lifetime characteristics.

And Li ₃ PO ₄ contained in the composite coating layer. By further including MgF ₂ in the composite coating layer, side reactions with the electrolyte can be further suppressed by including F in the coating layer.

The second compound may include a metal M and the metal M may be at least one element selected from the group consisting of Mg, Ni, Ti, Al, Si, Sn, Mn and Zr.

The metal M originates from the coating element of the first compound and includes the metal M, so that it plays a role not only in the Li adsorption of the first compound but also in the characterization of the cathode active material.

The content of the composite coating layer with respect to the total weight of the cathode active material may be 0.2 to 2.0 wt%. If the weight ratio is less than 0.2, the role of the coating layer may decrease. If the weight ratio is more than 2.0, the initial capacity decrease and the charge / discharge efficiency may be decreased. However, the present invention is not limited thereto.

The second compound comprising at least one metal M2 of Ni, Co, and Mn, independent of the compound capable of reversible intercalation and deintercalation of lithium, To 5% by weight.

If the content is less than 1 wt%, the role may be reduced. If the content is more than 5 wt%, the initial capacity decrease and the charge / discharge efficiency may be decreased. However, the present invention is not limited thereto.

Specific example, the reversible intercalation and de-intercalation is possible first compound of _{lithium, Li a A 1 - b X} b D 2 (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5); Li _a A _{1 - b} X _b O _{2 - c} T _c (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05); LiE _{1 - b} X _b O _{2 - c} D _c (0? B? 0.5, 0? C? 0.05); LiE _{2 - b} X _b O _{4 - c} T _c (0? B? 0.5, 0? C? 0.05); Li _a Ni _{1 -bc} Co _b X _c D _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2); Li _a Ni _{1 -bc} Co _b X _c O _2-α T _α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2); Li _a Ni _{1- b c} Co _b X _c O _2-α T ₂ (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2); Li _a Ni _{1 -b- c} Mn _b X _c D _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2); Li _a Ni _{1 -b- c} Mn _b X _c O _{2 - ?} T _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _{1 -b- c} Mn _b X _c O _{2 - ?} T ₂ (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _b E _c G _d O _{2 - e} T _e (0.90? A? 1.8, 0? B? 0.9, 0? C? 0.5, 0.001? D? 0.1, 0? E? 0.05); _{Li a Ni b Co c Mn d} G e O 2 - f T f (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1, 0 ≤ e ? 0.05); Li _a NiG _b O _{2 -c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a CoG _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a MnG ' _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a Mn ₂ G _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a MnG ' _b PO ₄ (0.90? A? 1.8, 0.001? B? 0.1); LiNiVO _4; And Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2). .

In the above formula, A is selected from the group consisting of Ni, Co, Mn, and combinations thereof; X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and combinations thereof; D is selected from the group consisting of O, F, S, P, and combinations thereof; E is selected from the group consisting of Co, Mn, and combinations thereof; T is selected from the group consisting of F, S, P, and combinations thereof; G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof; Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof; J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

In another embodiment of the present invention, there is provided a method of preparing a lithium secondary battery, comprising: preparing a first compound capable of reversible intercalation and deintercalation of lithium;

A lithium source; Phosphorus source; Metal M source; And a separate metal M2 source;

The lithium source to a first compound capable of reversible intercalation and deintercalation of lithium; Phosphorus source; Metal M source; And a separate source of metal M2 to provide a lithium source on the surface of the first compound capable of reversible intercalation and deintercalation of lithium; Phosphorus source; Metal M source; And a separate metal M2 source; And

The lithium source; Phosphorus source; Metal M source; And a second compound capable of reversible intercalation and deintercalation of lithium to which a separate metal M2 source is attached is subjected to a heat treatment to form Li ₃ PO ₄ and a lithium metal oxide, a metal oxide, Wherein the composite coating layer further comprises a first compound capable of reversibly intercalating and deintercalating lithium formed on the surface thereof and a second compound capable of reversibly intercalating and deintercalating lithium , A second compound including at least one metal M2 of Ni, Co, and Mn,

Wherein the metal M comprises at least one selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, V and Zr, Wherein at least one of the oxide and the metal oxide comprises a metal M independently from each other. The present invention also provides a method for producing a cathode active material for a lithium secondary battery.

The lithium source; Phosphorus source; Metal M source; And a second compound capable of reversible intercalation and deintercalation of lithium to which a separate metal M2 source is attached is subjected to a heat treatment to form Li ₃ PO ₄ and a lithium metal oxide, a metal oxide, Wherein the composite coating layer further comprises a first compound capable of reversibly intercalating and deintercalating lithium formed on the surface thereof and a second compound capable of reversibly intercalating and deintercalating lithium, , A second compound comprising at least one metal M2 selected from Co, and Mn; in,

The heat treatment temperature may be 650 to 950 캜. When the temperature is within the above range, the composite coating layer can be stably formed.

The description of the remaining configuration is the same as that of the above-described embodiment of the present invention, so that the description thereof will be omitted.

According to another embodiment of the present invention, there is provided a lithium secondary battery including a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode includes a current collector and a positive electrode active material layer formed on the current collector, And a lithium secondary battery comprising the above-described cathode active material.

The description related to the cathode active material is omitted since it is the same as the one embodiment of the present invention described above.

The cathode active material layer may include a binder and a conductive material.

The binder serves to adhere the positive electrode active material particles to each other and to adhere the positive electrode active material to the current collector. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl Polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-acrylonitrile, styrene-butadiene rubber, Butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, and the like, but not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any conductive material can be used without causing any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, Carbon-based materials such as black and carbon fiber; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives; Or a mixture thereof may be used.

The negative electrode includes a current collector and a negative active material layer formed on the current collector, and the negative active material layer includes a negative active material.

The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, a lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

As a material capable of reversibly intercalating / deintercalating lithium ions, any carbonaceous anode active material commonly used in lithium ion secondary batteries can be used as the carbonaceous material. Typical examples thereof include crystalline carbon , Amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in the form of amorphous, plate-like, flake, spherical or fibrous type. Examples of the amorphous carbon include soft carbon (soft carbon) Or hard carbon, mesophase pitch carbide, fired coke, and the like.

As the lithium metal alloy, a lithium-metal alloy may be selected from the group consisting of lithium, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, An alloy of a selected metal may be used.

As the material capable of doping and dedoping lithium, Si, SiO _x (0 <x <2), Si-Y alloy (Y is an alkali metal, an alkali earth metal, a Group 13 element, a Group 14 element, Rare earth elements and combinations thereof, but not Si), Sn, SnO ₂ , Sn-Y (wherein Y is at least one element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Element and an element selected from the group consisting of combinations thereof, and not Sn), and at least one of them may be mixed with SiO ₂ . The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Se, Te, Po, and combinations thereof.

Examples of the transition metal oxide include vanadium oxide, lithium vanadium oxide, and the like.

The negative electrode active material layer also includes a binder, and may optionally further include a conductive material.

The binder serves to adhere the anode active material particles to each other and to adhere the anode active material to the current collector. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, Such as polyvinyl chloride, polyvinyl fluoride, polymers comprising ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, Styrene-butadiene rubber, epoxy resin, nylon, and the like may be used, but the present invention is not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any conductive material can be used without causing any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, Carbon-based materials such as black and carbon fiber; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives; Or a mixture thereof may be used.

The collector may be selected from the group consisting of a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foil, a polymer substrate coated with a conductive metal, and a combination thereof.

As the current collector, Al may be used, but the present invention is not limited thereto.

The negative electrode and the positive electrode are prepared by mixing an active material, a conductive material and a binder in a solvent to prepare an active material composition, and applying the composition to a current collector. The method of manufacturing the electrode is well known in the art, and therefore, a detailed description thereof will be omitted herein. As the solvent, N-methylpyrrolidone or the like can be used, but it is not limited thereto.

The electrolyte includes a non-aqueous organic solvent and a lithium salt.

The non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

The non-aqueous organic solvent may be a carbonate, ester, ether, ketone, alcohol, or aprotic solvent. Examples of the carbonate solvent include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC) EC), propylene carbonate (PC), and butylene carbonate (BC) may be used. As the ester solvent, methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate , gamma -butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone, and the like can be used. Examples of the ether solvent include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, and tetrahydrofuran. As the ketone solvent, cyclohexanone may be used have. As the alcoholic solvent, ethyl alcohol, isopropyl alcohol and the like can be used. As the aprotic solvent, R-CN (R is a linear, branched or cyclic hydrocarbon group having 2 to 20 carbon atoms, , A double bond aromatic ring or an ether bond), and dioxolanes such as 1,3-dioxolane, sulfolanes, and the like can be used.

The non-aqueous organic solvent may be used alone or in admixture of one or more. If the non-aqueous organic solvent is used in combination, the mixing ratio may be appropriately adjusted according to the performance of the desired cell. .

In the case of the carbonate-based solvent, it is preferable to use a mixture of a cyclic carbonate and a chain carbonate. In this case, when the cyclic carbonate and the chain carbonate are mixed in a volume ratio of 1: 1 to 1: 9, the performance of the electrolytic solution may be excellent.

The non-aqueous organic solvent according to an embodiment of the present invention may further include an aromatic hydrocarbon-based organic solvent in the carbonate-based solvent. In this case, the carbonate-based solvent and the aromatic hydrocarbon-based organic solvent may be mixed in a volume ratio of 1: 1 to 30: 1.

The aromatic hydrocarbon-based organic solvent may be an aromatic hydrocarbon-based compound represented by the following formula (1).

[Chemical Formula 1]

(Wherein R ₁ to R ₆ are each independently hydrogen, halogen, a C1 to C10 alkyl group, a haloalkyl group, or a combination thereof)

The aromatic hydrocarbon-based organic solvent is selected from the group consisting of benzene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3- , 1,2,4-trifluorobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 4-trichlorobenzene, iodobenzene, 1,2-diiodobenzene, 1,3-diiodobenzene, 1,4-diiodobenzene, 1,2,3-triiodobenzene, 1,2,4 - triiodobenzene, toluene, fluorotoluene, 1,2-difluorotoluene, 1,3-difluorotoluene, 1,4-difluorotoluene, 1,2,3-trifluorotoluene, 1,2,4-trifluorotoluene, chlorotoluene, 1,2-dichlorotoluene, 1,3-dichlorotoluene, 1,4-dichlorotoluene, 1,2,3-trichlorotoluene, 1,2,4 - trichlorotoluene, iodotoluene, 1,2-diiodotoluene, 1,3-diiodotoluene, 1,4-diiodotol Yen, it is 1,2,3-tree-iodo toluene, 1,2,4-iodo toluene, xylene, and selected from the group consisting of.

The non-aqueous electrolyte may further include vinylene carbonate or an ethylene carbonate-based compound represented by the following formula (2) to improve battery life.

(2)

(In Formula 2, R ₇ and R ₈ are each independently hydrogen, halogen, cyano (CN), nitro group (NO ₂₎ or a C1 to a to C5 fluoroalkyl group, at least one of the R ₇ and R ₈ Is a halogen group, a cyano group (CN), a nitro group (NO ₂ ) or a C1 to C5 fluoroalkyl group.

Representative examples of the ethylene carbonate-based compound include diethylene carbonate, diethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, fluoroethylene carbonate, and the like, such as difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, . When such a life improving additive is further used, its amount can be appropriately adjusted.

The lithium salt is dissolved in an organic solvent to act as a source of lithium ions in the cell to enable operation of a basic lithium secondary battery and to promote the movement of lithium ions between the anode and the cathode. The lithium salt Representative examples are _{LiPF 6, LiBF 4, LiSbF 6} , LiAsF 6, LiC 4 F 9 SO 3, LiClO 4, LiAlO 2, LiAlCl 4, LiN (C x F 2x + 1 SO 2) (C y F 2y ₊₁ SO ₂₎ (where, x and y are natural numbers), LiCl, LiI, and _{LiB (C 2 O 4) 2} ( lithium bis oxalate reyito borate (lithium bis (oxalato) borate; LiBOB) is selected from the group consisting of The concentration of the lithium salt is preferably in the range of 0.1 to 2.0 M. When the concentration of the lithium salt is within the above range, the electrolyte has appropriate conductivity and viscosity Can exhibit excellent electrolyte performance, and lithium ions can effectively migrate.

Depending on the type of the lithium secondary battery, a separator may exist between the positive electrode and the negative electrode. The separator may be a polyethylene / polypropylene double layer separator, a polyethylene / polypropylene / polyethylene triple layer separator, a polypropylene / polyethylene / poly It is needless to say that a mixed multilayer film such as a propylene three-layer separator and the like can be used.

The lithium secondary battery can be classified into a lithium ion battery, a lithium ion polymer battery, and a lithium polymer battery depending on the type of the separator and electrolyte used. The lithium secondary battery can be classified into a cylindrical shape, a square shape, a coin shape, Depending on the size, it can be divided into bulk type and thin type. The structure and the manufacturing method of these cells are well known in the art, and detailed description thereof will be omitted.

FIG. 1 schematically shows a representative structure of the lithium secondary battery of the present invention. 1, the lithium secondary battery 1 includes a positive electrode 3, a negative electrode 2, and a battery 4 including an electrolyte solution impregnated in the separator 4 existing between the positive electrode 3 and the negative electrode 2, And a sealing member (6) for sealing the battery container (5).

Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are only illustrative of the present invention and are not intended to limit the scope of the present invention.

Example

Example 1

A mixer LiCoO ₂ of 100g and 0.054g LiOH powder and Zr (OH) ₄ powder and SiO ₂ powder 0.172g 0.054g and (NH _{4) 2} HPO ₄ powder, 0.387g, CoOOH 4000ppm the powder by dry mixing LiCoO _2, the main body The mixture adhered to the surface was prepared, and then the mixture was heat-treated at 800 DEG C for 6 hours to prepare a cathode active material.

Example 2

100 g of LiCoO _2, 0.054 g of LiOH powder, 0.387 g of (NH ₄ ) ₂ HPO ₄ powder and 4000 ppm of CoOOH were dry mixed to prepare a mixture in which the powder was adhered to the surface of the LiCoO ₂ body, The cathode active material was prepared by heat treatment for 6 hours.

Example 3

100 g of LiCoO _2, 0.054 g of LiOH powder, 0.387 g of (NH ₄ ) ₂ HPO ₄ powder, 4000 ppm of CoOOH and 1000 ppm of MgF ₂ were dry mixed to prepare a mixture in which the powder was attached to the surface of the LiCoO ₂ body, Was heat-treated at 800 DEG C for 6 hours to prepare a cathode active material.

Example 4

A mixer LiCoO ₂ 100g and 0.054g LiOH powder and Zr (OH) ₄ powder and SiO ₂ powder 0.172g 0.054g and (NH _{4) 2} HPO ₄ powder, 0.387g, Ni _{0. 35} Co _{0 . 30 Mn 0 .35 (OH) 2} 3.5g was prepared with a dry mixed to prepare a mixture of the powder attached to the surface of the LiCoO ₂ positive electrode body and then heat-treating the mixture 6 hours at 800 ℃ active material.

Example 5

LiNi _{0 in the} mixer _{. 60} Co _{0 . 20} Mn _{0 . 20} O _2, 0.054 g of LiOH powder, 0.259 g of MgCO ₃ powder, 0.615 g of TiO ₂ powder, and 0.387 g of CoOOH 4000 ppm of (NH ₄ ) ₂ HPO ₄ powder were mixed and the powder was mixed with LiNi _{0 . 60} Co _{0 . 20} Mn _{0 . 20} O ₂ , and the mixture was heat-treated at 700 ° C. for 6 hours to prepare a cathode active material.

Comparative Example 1

100 g of LiCoO _2, 0.054 g of LiOH powder, 0.172 g of Zr (OH) ₄ powder, 0.054 g of SiO ₂ powder and 0.387 g of (NH ₄ ) ₂ HPO ₄ powder were mixed in the mixer and the powder was adhered to the surface of the LiCoO ₂ body And the mixture was heat-treated at 800 DEG C for 6 hours to prepare a cathode active material.

Comparative Example 2

100 g of LiCoO _2, 0.054 g of LiOH powder and 0.387 g of (NH ₄ ) ₂ HPO ₄ powder were dry mixed to prepare a mixture in which the powder was adhered to the surface of the LiCoO ₂ body, followed by heat treatment at 800 ° C. for 6 hours To prepare a cathode active material.

Comparative Example 3

General LiCoO ₂ was prepared.

Comparative Example 4

100 g of LiCoO _2, 0.054 g of LiOH powder and 4000 ppm of CoOOH were dry mixed to prepare a mixture in which the powder was adhered to the surface of the LiCoO ₂ body, and the mixture was heat-treated at 800 ° C for 6 hours to prepare a cathode active material.

Comparative Example 5

The cathode active material was prepared in the same manner as in Example 5, except that CoOOH was excluded from the mixer to produce a mixture by dry mixing.

Manufacture of Coin Cell

N-methyl-2-pyrrolidone (NMP) as a solvent was mixed with 95 weight% of the cathode active material prepared in the above Examples and Comparative Examples, 2.5 weight% of carbon black as a conductive agent and 2.5 weight% of PVDF as a binder. To 5.0 wt% to prepare a positive electrode slurry. The positive electrode slurry was coated on an aluminum (Al) thin film as a positive electrode current collector having a thickness of 20 to 40 mu m, followed by vacuum drying and roll pressing to produce a positive electrode.

Li-metal was used as the cathode.

A coin-cell type half-cell was fabricated by using the thus prepared positive electrode and Li-metal as a counter electrode and using 1.15M LiPF6EC: DMC (1: 1 vol%) as an electrolyte solution.

Charging and discharging were performed in the range of 4.5-3.0V.

Experimental Example 1: Evaluation of Battery Characteristics

Table 1 below shows the 4.5 V initial formations, rate characteristics, 1 cycle, 20 cycle, 30 cycle capacity and life characteristic data of the examples and comparative examples. Table 2 shows information on the coating layers of the above-described Examples and Comparative Examples.

Formation
Discharge capacity (mAh / g) efficiency 1CY
Discharge capacity 20CY
Discharge capacity 30CY
Discharge capacity Life characteristics
(20CY /
1CY,%) Life characteristics
(30CY /
1CY,%) Rate characteristic
(3.0 / 0.1C,%) Example 1 192.33 97.86 190.15 184.51 181.86 97.03 95.64 93.62 Example 2 193.12 97.81 191.22 185.68 182.97 97.10 95.69 93.72 Example 3 192.54 97.59 190.38 186.97 186.24 98.21 97.83 93.64 Example 4 193.82 97.59 190.97 188.25 186.31 98.58 97.56 94.12 Example 5 196.18 89.11 190.67 177.57 168.27 93.13 88.25 87.55 Comparative Example 1 191.79 97.44 188.70 180.03 179.15 95.41 94.94 92.87 Comparative Example 2 193.01 97.35 191.25 185.27 180.94 96.87 94.61 92.91 Comparative Example 3 192.69 94.62 189.57 168.57 150.47 88.92 79.37 86.19 Comparative Example 4 192.85 96.38 190.51 183.67 178.69 96.41 93.80 92.22 Comparative Example 5 195.55 87.96 190.54 176.66 164.64 92.72 86.41 85.64

Coated element Coating layer compound The second compound Example 1 Li, Zr, Si, P, Co Li ₃ PO ₄ , Li ₂ ZrO ₃ , Li ₂ SiO ₃ , ZrO ₂ , SiO ₂ LiCoO ₂ Example 2 Li, P, Co Li ₃ PO ₄ LiCoO ₂ Example 3 Li, Mg, P, F, Co Li ₃ PO ₄ , LiF, MgF ₂ , Li ₂ MgO ₂ , MgO LiCoO ₂ Example 4 Li, Zr, Si, P, Ni, Co, Mn Li ₃ PO ₄ , Li ₂ ZrO ₃ , Li ₂ SiO ₃ , ZrO ₂ , SiO ₂ LiNiCoMnO ₂ Example 5 Li, Mg, Ti, P, Co Li ₃ PO ₄ , Li ₂ MgO ₂ , Li ₂ TiO ₃ , MgO, TiO ₂ LiCoO ₂ Comparative Example 1 Li, Zr, Si, P Li ₃ PO ₄ , Li ₂ ZrO ₃ , Li ₂ SiO ₃ , ZrO ₂ , SiO ₂ - Comparative Example 2 Li, P Li ₃ PO ₄ - Comparative Example 3 - - - Comparative Example 4 Li, Co - LiCoO ₂ Comparative Example 5 Li, Mg, Ti, P Li ₃ PO ₄ , Li ₂ MgO ₂ , Li ₂ TiO ₃ , MgO, TiO ₂ LiCoO ₂

In Table 1, the battery characteristics of Examples 1 to 4 are superior to those of Comparative Examples 1 to 4.

More specifically, a second compound containing at least one element selected from a metal M2 consisting of Ni, Co, and Mn, which is separate from a compound capable of reversibly intercalating and deintercalating lithium, Are superior to those of the cathode active materials of Comparative Examples 1 to 4 in terms of resistance and service life characteristics. Comparing Example 2 and Comparative Examples 2 and 4, superior battery characteristics were confirmed in Example 2 including at least one element selected from the metal M2 consisting of Ni, Co, and Mn apart from the composite coating layer.

Also in the comparison between Example 5 and Comparative Example 5 in which the composition was different, the above battery characteristics were found to be different.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (17)

A first compound capable of reversible intercalation and deintercalation of lithium; And a second compound that is independent of the first compound and comprises at least one metal M2 of Ni, Co, and Mn,
A coating layer disposed on at least a portion of the surface of the first compound,
Wherein the coating layer comprises Li ₃ PO ₄ and the coating layer is a composite coating layer further comprising a lithium metal oxide, a metal oxide, or a combination thereof,
Wherein at least one of the lithium metal oxide and the metal oxide includes a metal M and the metal M 1 is at least one selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Cr, Fe, V, and Zr. The positive electrode active material for a lithium secondary battery according to claim 1, wherein the positive electrode active material is at least one element selected from the group consisting of Cr, Fe, V and Zr.
The method according to claim 1,
The lithium of Li ₃ PO ₄ , LiF, and / or the lithium metal oxide contained in the composite coating layer may be derived from Li contained in the first compound capable of reversible intercalation and deintercalation of lithium, Lt; RTI ID = 0.0 &gt; Li &lt; / RTI &gt; supply material.
The method according to claim 1,
The second compound may be,
Wherein the reversible intercalation and deintercalation of lithium can be performed.
The method according to claim 1,
The second compound may be,
Co as a positive electrode active material for a lithium secondary battery.
5. The method of claim 4,
The second compound may be,
And a Li deficient compound (Li / M ratio < 1.0).
The method according to claim 1,
Wherein the composite coating layer further comprises LiF. The method according to claim 1,
The second compound may be,
Wherein the metal M is at least one element selected from the group consisting of Mg, Ni, Ti, Al, Si, Sn, Mn and Zr.
The method according to claim 1,
The P of Li ₃ PO ₄ contained in the composite coating layer may be,
Wherein the positive active material is derived from a separately provided P compound.
The method according to claim 1,
Wherein the composite coating layer further comprises MgF ₂ .
The method according to claim 1,
Wherein the lithium metal oxide contained in the composite coating layer is LiAlO ₂ , Li ₂ MgO ₂ , Li ₂ TiO ₃ , Li ₂ ZrO ₃ , Li ₂ SiO ₃ , Li ₄ SiO _4, or a combination thereof.
The method according to claim 1,
Contained in the composite coating layer of metal oxide is _{Al 2 O 3, MgO, TiO} 2, ZrO 2, SiO 2, or combinations thereof would a cathode active material for a lithium secondary battery.
The method according to claim 1,
The first compound capable of reversible intercalation and deintercalation of lithium is Li _a A _{1 - b} X _b D ₂ (0.90? A? 1.8, 0? B? 0.5); Li _a A _{1 - b} X _b O _{2 - c} T _c (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05); LiE _{1 - b} X _b O _{2 - c} D _c (0? B? 0.5, 0? C? 0.05); LiE _2-b X _b O _4-c T _c (0? B? 0.5, 0? C? 0.05); Li _a Ni _{1 -b- c} Co _b X _c D _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2); Li _a Ni _{1 -b- c} Co _b X _c O _{2 - ?} T _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Co _b X _c O _{2 - ?} T ₂ (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _{1 -b- c} Mn _b X _c D _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2); Li _a Ni _{1 -b- c} Mn _b X _c O _{2 - ?} T _? (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _{1 -b- c} Mn _b X _c O _{2 - ?} T ₂ (0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? <2); Li _a Ni _b E _c G _d O _{2 -e} T _e (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1, 0 ≤ e ≤ 0.05); _{Li a Ni b Co c Mn d} G e O 2 - f T f (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1, 0 ≤ e ? 0.05); Li _a NiG _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a CoG _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a MnG ' _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a Mn ₂ G _b O _{2 - c} T _c (0.90? A? 1.8, 0.001? B? 0.1, 0? C? 0.05); Li _a MnG ' _b PO ₄ (0.90? A? 1.8, 0.001? B? 0.1); LiNiVO _4; And Li _(3-f) J ₂ (PO ₄ ) ₃ (0 ≦ f ≦ 2). 2. The lithium secondary battery according to claim 1,
In the above formula, A is selected from the group consisting of Ni, Co, Mn, and combinations thereof; X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and combinations thereof; D is selected from the group consisting of O, F, S, P, and combinations thereof; E is selected from the group consisting of Co, Mn, and combinations thereof; T is selected from the group consisting of F, S, P, and combinations thereof; G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof; Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof; J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.
The method according to claim 1,
Wherein the content of the composite coating layer with respect to the total weight of the cathode active material is 0.2 to 2.0 wt%.
The method according to claim 1,
The second compound may be,
And 1 to 5% by weight based on the total amount of the total cathode active material.
Preparing a first compound capable of reversible intercalation and deintercalation of lithium;
A lithium source; Phosphorus source; Metal M source; And a separate metal M2 source;
The lithium source to a first compound capable of reversible intercalation and deintercalation of lithium; Phosphorus source; Metal M source; And a separate source of metal M2 to provide a lithium source on the surface of the first compound capable of reversible intercalation and deintercalation of lithium; Phosphorus source; Metal M source; And a separate metal M2 source; And
The lithium source; Phosphorus source; Metal M source; And a first compound capable of reversible intercalation and deintercalation of lithium to which a separate metal M2 source is attached,
A first compound capable of reversibly intercalating and deintercalating lithium in which a composite coating layer containing Li ₃ PO ₄ and further including a lithium metal oxide, a metal oxide, or a combination thereof is formed on the surface, and
Obtaining a cathode active material comprising a second compound comprising at least one metal M2 selected from Ni, Co, and Mn independently of the first compound compound;
, &Lt; / RTI &
Wherein the metal M comprises at least one selected from the group consisting of Na, K, Mg, Ca, Sr, Ni, Co, Ti, Al, Si, Sn, Mn, Cr, Fe, V and Zr,
Wherein at least one of the lithium metal oxide and the metal oxide comprises a metal M independently from each other.
16. The method of claim 15,
The lithium source; Phosphorus source; Metal M source; And a second compound capable of reversible intercalation and deintercalation of lithium to which a separate metal M2 source is attached is subjected to a heat treatment to form Li ₃ PO ₄ and a lithium metal oxide, a metal oxide, A first compound capable of reversibly intercalating and deintercalating lithium formed on the surface of the composite coating layer,
Obtaining a cathode active material comprising a second compound comprising at least one metal M2 of Ni, Co, and Mn, independently of the first compound compound capable of reversible intercalation and deintercalation of lithium step; in,
And the heat treatment temperature is 650 to 950 占 폚.
A positive electrode comprising a positive electrode active material for a lithium secondary battery according to any one of claims 1 to 14;
A negative electrode comprising a negative electrode active material; And
Electrolyte;
&Lt; / RTI &gt;

Images