JP2020149901A - Manufacturing method of positive electrode material for lithium ion secondary battery, positive electrode material for lithium ion secondary battery, manufacturing method of positive electrode mixture for lithium ion secondary battery, and lithium ion secondary battery - Google Patents

Abstract

To provide a manufacturing method of a positive electrode material for a lithium ion secondary battery, in which the cycle characteristics are unlikely to deteriorate even when the amount of nickel relative to cobalt is relatively high.SOLUTION: The manufacturing method of a positive electrode material for a lithium ion secondary battery is provided in which lithium metal composite oxide powder including lithium (Li), nickel (Ni), cobalt (Co), and an element M with an atomic number ratio represented by Li:Ni:Co:M=z:(1-x-y):x:y (however, 0.97≤z≤1.20, 0≤x<0.01, 0≤y≤0.10, 0≤x+y≤0.10, M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al), and a tungsten oxide material having tungsten oxide with a particle size of 0.01 to 0.09 μm, and lithium tungstate with a particle size of 0.01-0.09 μm are mixed.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a positive electrode material for a lithium ion secondary battery, a positive electrode material for a lithium ion secondary battery, a method for producing a positive electrode mixture for a lithium ion secondary battery, and a lithium ion secondary battery.

In recent years, with the spread of portable electronic devices such as mobile phones and notebook computers, the development of small and lightweight non-aqueous electrolyte secondary batteries with high energy density has been strongly desired, and electric vehicles such as hybrid vehicles have been strongly desired. The development of a high-power secondary battery as a battery for use is also strongly desired.

As a secondary battery satisfying such a requirement, there is a lithium ion secondary battery.

In this lithium ion secondary battery, a material capable of desorbing and inserting lithium is used as the active material of the negative electrode and the positive electrode.

Currently, research and development of such lithium ion secondary batteries are being actively carried out. Among them, lithium ion secondary batteries using a layered or spinel type lithium metal composite oxide as a positive electrode material are used. Since a high voltage of 4V class can be obtained, it is being put into practical use as a battery having a high energy density.

As active material materials proposed so far, lithium cobalt composite oxide (LiCoO ₂ ), which is relatively easy to synthesize, lithium nickel composite oxide (LiNiO ₂ ) using nickel, which is cheaper than cobalt, and lithium. Nickel cobalt manganese composite oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), lithium manganese composite oxide using manganese (LiMn ₂ O ₄ ) and the like can be mentioned.

Of these, lithium-nickel composite oxide and lithium-nickel-cobalt-manganese composite oxide are attracting attention as materials with good cycle characteristics, low resistance, high output, and excellent battery characteristics, and have been required for higher output in recent years. It is important to reduce the resistance.

As a method for improving such battery characteristics, addition of a different element is used, and in particular, a transition metal such as W, Mo, Nb, Ta, Re, which can take an expensive number, is considered to be useful.

For example, Patent Document 1 proposes a positive electrode material capable of providing high capacity and high output by mixing lithium metal composite oxide powder and lithium tungstate as a positive electrode material for a non-aqueous electrolyte secondary battery. There is. Further, Patent Document 2 states that the same effect can be obtained by mixing lithium metal composite oxide powder and tungsten oxide.

Japanese Unexamined Patent Publication No. 2013-171785 Japanese Unexamined Patent Publication No. 2012-28313

For the further spread of electric vehicles, it is necessary to further increase the capacity and cost of lithium-ion secondary batteries. Therefore, it is considered to reduce the amount of cobalt contained in the positive electrode active material and increase the amount of nickel. Has been done.

However, with such a measure, nickel oxide is likely to be formed on the surface of the positive electrode active material, and the structure of the positive electrode active material may become unstable. In particular, the formation of nickel oxide can not only increase the resistance of the positive electrode active material, but also cause a non-uniform lithium desorption reaction. Further, if the desorption reaction of lithium occurs locally in the positive electrode active material, there may be a problem that the cycle characteristics of the secondary battery are deteriorated.

The present invention has been made in view of such a background, and in the present invention, even when the amount of nickel with respect to cobalt is relatively increased, the cycle characteristics are unlikely to be deteriorated for a lithium ion secondary battery. It is an object of the present invention to provide a method for producing a positive electrode material and a method for producing a positive electrode mixture for a lithium ion secondary battery. Further, the present invention provides a positive electrode material for a lithium ion secondary battery and a lithium ion secondary battery in which the cycle characteristics are unlikely to deteriorate even when the amount of nickel relative to cobalt is relatively increased. The purpose.

In the present invention
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y.
(However, 0.97 ≦ z ≦ 1.20, 0 ≦ x <0.01, 0 ≦ y ≦ 0.10, 0 ≦ x + y ≦ 0.10. M is Mn, V, Mg, Mo, Nb, Lithium metal composite oxide powder contained in an atomic number ratio represented by (at least one element selected from Ti and Al), tungsten oxide having a particle size of 0.01 to 0.09 μm, or a particle size of 0.01 to 0. Provided is a method for producing a positive electrode material for a lithium ion secondary battery, which comprises mixing a tungsten-added material of .09 μm lithium tartrate.

Further, in the present invention,
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Species element) Lithium metal composite oxide powder contained in the atomic number ratio represented by v, at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, and a particle size of 0.01 to 0. Provided is a method for producing a positive electrode material for a lithium ion secondary battery, which comprises mixing a tungsten oxide material of .09 μm or a tungsten-added material of lithium tartrate having a particle size of 0.01 to 0.09 μm.

Here, the production method may include a step of washing the lithium metal composite oxide powder with water before mixing the lithium metal composite oxide powder and the tungsten-added material.

Further, the amount of tungsten contained in the positive electrode material may be 0.1 to 3.0 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M contained in the lithium metal composite oxide powder. Good.

Further, the tungsten-added material may be tungsten oxide of WO ₃ , or at least one lithium tungstate selected from Li ₂ WO ₄ , Li ₄ WO ₅ , and Li ₆ W ₂ O ₉ .

Further, in the present invention,
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by (species element) and tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tungstate having a particle size of 0.01 to 0.09 μm. Provided is a positive electrode material for a lithium ion secondary battery, which comprises an additive material.

Further, in the present invention,
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by the element of the species), at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, and a particle size of 0.01 to 0. Provided is a positive electrode material for a lithium ion secondary battery, which comprises a tungsten oxide material of 09 μm or a tungsten-added material of lithium tartrate having a particle size of 0.01 to 0.09 μm.

Here, the amount of tungsten contained in the positive electrode material is 0.1 to 3.0 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M contained in the lithium metal composite oxide powder. May be good.

Further, the tungsten-added material may be tungsten oxide of WO ₃ , or at least one lithium tungstate selected from Li ₂ WO ₄ , Li ₄ WO ₅ , and Li ₆ W ₂ O ₉ .

Further, the tungsten-added material may be lithium tungstate containing Li ₄ WO ₅ when it is lithium tungstate.

Further, in the present invention,
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by (species element), N-methyl-2-pyrrolidinone, tungsten oxide having a particle size of 0.01 to 0.09 μm or a particle size of 0.01 to 0 Provided is a positive electrode material for a lithium ion secondary battery, which comprises a tung-added material of .09 μm lithium tartrate.

Further, the present invention provides a lithium ion secondary battery characterized by having a positive electrode containing the above-mentioned positive electrode material for a lithium ion secondary battery.

Further, in the present invention,
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by (seed element) and tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tungstate having a particle size of 0.01 to 0.09 μm are added. Production of a positive electrode mixture for a lithium ion secondary battery, which comprises mixing a conductive material and a binder with a mixture with the material and N-methyl-2-pyrrolidinone, which is a solvent for dissolving the binder. The method is provided.

Further, in the present invention,
Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least one selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder containing an atomic number ratio represented by (species element), at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, and a particle size of 0.01 to 0. In a mixture of 09 μm tungsten oxide or a lithium tungsten-added material having a particle size of 0.01 to 0.09 μm,
Provided is a method for producing a positive electrode mixture for a lithium ion secondary battery, which comprises mixing a conductive material and a binder with N-methyl-2-pyrrolidinone, a solvent that dissolves the binder.

Further, the present invention provides a lithium ion secondary battery characterized by having a positive electrode including the above-mentioned positive electrode mixture for a lithium ion secondary battery.

In the present invention, a method for producing a positive electrode material for a lithium ion secondary battery and a positive electrode mixture for a lithium ion secondary battery, in which the cycle characteristics are unlikely to deteriorate even when the amount of nickel relative to cobalt is relatively increased. Manufacturing method can be provided. Further, in the present invention, it is possible to provide a positive electrode material for a lithium ion secondary battery and a lithium ion secondary battery in which the cycle characteristics are unlikely to deteriorate even when the amount of nickel relative to cobalt is relatively increased. it can.

The manufacturing method of the present invention is easy and suitable for production on an industrial scale, and its industrial value is extremely large.

It is a schematic explanatory diagram of the measurement example of impedance evaluation and the equivalent circuit used for analysis. It is the schematic sectional drawing of the coin type battery 1 used for the battery evaluation.

Hereinafter, the present invention will be described in detail. First, the positive electrode active material (positive electrode material) of the present invention will be described, and then a method for producing the positive electrode active material and a non-aqueous electrolyte secondary battery using the positive electrode active material will be described.

(1) Positive electrode active material (positive electrode material)
The positive electrode material for a lithium ion secondary battery of the present invention contains lithium (Li), nickel (Ni), cobalt (Co), and element M, Li: Ni: Co: M = z: (1-xy). ): X: y (where 0.97 ≦ z ≦ 1.20, 0 ≦ x <0.01, 0 ≦ y ≦ 0.10, 0 ≦ x + y ≦ 0.10, M is Mn, V, Mg , Mo, Nb, Ti and Al) and lithium metal composite oxide powder contained in the atomic number ratio represented by the atomic number ratio, and tungsten oxide having a particle size of 0.01 to 0.09 μm, or a particle size. It is characterized in that it is mixed with a tungsten-added material of 0.01 to 0.09 μm lithium tartrate.

In the present invention, as a positive electrode active material comprising a base material, the general formula _{Li z Ni 1-x-y} Co x M y O 2 + α ( although, 0 ≦ x <0.01,0 ≦ y ≦ 0.10,0 ≤x + y≤0.10, 0.97≤z≤1.20, -0.2≤α≤0.2, M is an additive element and is selected from Mn, V, Mg, Mo, Nb, Ti and Al. By using the lithium metal composite oxide powder represented by at least one element), a high charge / discharge capacity can be obtained, and the lithium metal composite oxide powder and oxidation having a particle size of 0.01 to 0.09 μm can be obtained. By mixing tungsten or a tungsten-added material of lithium tungstenate having a particle size of 0.01 to 0.09 μm, the output characteristics are improved while maintaining the charge / discharge capacity.

The lithium metal composite oxide preferably has a layered hexagonal rock salt type crystal structure.

In the positive electrode material for a lithium ion secondary battery according to an embodiment of the present invention, a tungsten-added material is present on the surfaces of the primary particles and the secondary particles of the lithium metal composite oxide powder (hereinafter, also referred to as “skeleton material”). .. Due to the presence of the tungsten-added material, it is possible to significantly suppress an increase in the resistance of the positive electrode active material even when the amount of nickel contained in the skeleton material is relatively high with respect to the amount of cobalt.

Further, as a result, the desorption of lithium ions occurs relatively uniformly in the entire positive electrode material, and the deterioration of the cycle characteristics of the positive electrode material can be significantly suppressed.

It is considered that the tungsten oxide used in the present invention reacts with the excess lithium on the surface of the positive electrode active material to change to lithium tungstate and exists on the surface of the active material.

Lithium tungate is also a compound having high lithium ion conductivity, but in the case of lithium tungstate, it is simply mixed with the lithium metal composite oxide and dispersed between the particles of the lithium metal composite oxide. It has the effect of promoting the movement of lithium and significantly reducing the positive electrode resistance.

When this lithium tartrate is uniformly present as fine particles on the surface of the active material, it acts on the electrolytic solution or the positive electrode active material to form a lithium conduction path between the electrolytic solution and the positive electrode active material interface. The reaction resistance of the active material is reduced to improve the output characteristics.

When tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tantistate having a particle size of 0.01 to 0.09 μm, which is a tungsten-added material, is unevenly distributed in the positive electrode material, a lithium metal composite oxide Since the movement of lithium ions becomes non-uniform between the particles, a load is applied to specific lithium metal composite oxide particles, which tends to cause deterioration of cycle characteristics and increase of reaction resistance.

Therefore, fine particles of lithium tungstate are uniformly present on the surface of the active material, and tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tungstate having a particle size of 0.01 to 0.09 μm is uniformly present in the positive electrode material. It is preferably distributed.

Therefore, it is necessary to uniformly disperse the fine particles of tungsten oxide or lithium tungstate in the surface of the positive electrode active material and in the positive electrode material, and the particle size is preferably 0.01 to 0.09 μm, preferably 0.01 to 0.09 μm. It is more preferably 0.05 μm.

If the particle size is less than 0.01 μm, the pulverization cost may be too high, which is not preferable. If the particle size exceeds 0.09 μm, lithium tungstate cannot be uniformly adhered to the surface of the positive electrode material, resulting in a reaction. It is not preferable because the effect of reducing resistance may not be sufficiently obtained.

For this particle size, the average particle size measured by the laser diffraction / scattering method or the volume integration average value in Microtrac is used.

When the particle size exceeds the above range, it is preferable to pulverize the particles before mixing.

Further, the amount of tungsten contained in this positive electrode material is 0.1 to 3.0 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M contained in the mixed lithium metal composite oxide powder. Is preferable.

As a result, both high charge / discharge capacity and output characteristics can be achieved, but if the amount of tungsten is less than 0.1 atomic%, fine particles cannot be uniformly provided on the surface of the active material, and the effect of improving the output characteristics can be improved. It may not be enough. On the other hand, when the amount of tungsten exceeds 3.0 atomic%, the amount of lithium tungstate becomes too large and the lithium conduction between the lithium metal composite oxide and the electrolytic solution is hindered, or the amount of the active material is relatively reduced. The discharge capacity may decrease.

The lithium tungstate is preferably at least one selected from Li ₂ WO ₄ , Li ₄ WO ₅ or Li ₆ W ₂ O _9, and more preferably contains Li ₄ WO ₅ .

It is particularly preferable that the lithium tungstate contains 50% or more of Li ₄ WO ₅ .

These lithium tungstates have high lithium ion conductivity, and the above effects can be sufficiently obtained by mixing with lithium metal composite oxide powder.

The amount of lithium in the lithium metal composite oxide is 0 as the ratio (Li / Me) of the sum of the number of atoms of nickel, cobalt and the additive element M (Me) in the lithium metal composite oxide to the number of atoms of lithium (Li). It is .97 to 1.20.

If Li / Me is less than 0.97, the reaction resistance of the positive electrode in the non-aqueous electrolyte secondary battery using the positive electrode material becomes large, so that the output of the battery becomes low. Further, when Li / Me exceeds 1.20, the discharge capacity of the positive electrode material decreases and the reaction resistance of the positive electrode also increases. Therefore, in order to obtain a larger discharge capacity, it is preferable to set Li / Me to 1.10 or less.

Co and the additive element M are added in order to improve battery characteristics such as cycle characteristics and output characteristics, and when x and y indicating the amount of these additions exceed 0.10, they contribute to the Redox reaction. Since Ni decreases, the battery capacity decreases.

Therefore, in order to obtain a sufficient battery capacity when used in a battery, it is preferable that y indicating the amount of the additive element M added is 0.1 or less.

Further, since increasing the contact area with the electrolytic solution is advantageous for improving the output characteristics, lithium metal composite oxide particles composed of primary particles and secondary particles formed by aggregating the primary particles are used. ..

In the positive electrode material of the present invention, fine particles of tungsten oxide or lithium tungstate are mixed with an organic solvent by mixing a lithium metal composite oxide powder and a fine powder of tungsten oxide or lithium tungstate on the surface of the positive electrode active material and in the positive electrode material. The output characteristics are improved by uniformly dispersing, and the powder characteristics such as the particle size and tap density of the lithium metal composite oxide as the positive electrode active material are within the range of the commonly used positive electrode active material. Well, the lithium metal composite oxide may be obtained by a known method, and those satisfying the above composition and powder characteristics can be used.

The effect obtained by mixing the lithium metal composite oxide powder with tungsten oxide or lithium tungstate is, for example, a lithium cobalt-based composite oxide, a lithium manganese-based composite oxide, a lithium nickel cobalt manganese-based composite oxide, or the like. It can be applied not only to the positive electrode active material described in the present invention but also to the commonly used positive electrode active material for a lithium secondary battery.

(2) In the manufacturing method of the positive electrode active material a positive electrode material for a nonaqueous electrolyte secondary battery manufacturing method present invention (positive electrode material), as the positive electrode active material as a base material, the general formula Li z _{Ni 1-x-y Co x M y O 2 + α} ( although, 0 ≦ x <0.01,0 ≦ y ≦ 0.10,0 ≦ x + y ≦ 0.10,0.97 ≦ z ≦ 1.20, -0.2 ≦ α ≦ 0.2 and M are additive elements, and lithium metal composite oxide powder represented by (at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al), ethanol, methanol and propanol. , Butanol, and acetonitrile are mixed with at least one organic solvent and a tungsten oxide material having a particle size of 0.01 to 0.09 μm of tungsten oxide or lithium tungstenate having a particle size of 0.01 to 0.09 μm. To do.

After mixing, the positive electrode material containing the solvent may be dried, or may be used as it is in the production of the positive electrode mixture. Drying may be performed by a known method and conditions, and may be performed within a range in which the battery characteristics of the lithium metal composite oxide are not deteriorated.

Lithium metal composite oxide powder and tungsten oxide or lithium tungstate need to be sufficiently mixed in order to form fine particles on the surface of the positive electrode active material and uniformly disperse the fine particles in the positive electrode material. In the invention, at least one organic substance selected from ethanol, methanol, propanol, butanol, and acetonitrile having good wettability with the lithium metal composite oxide powder when the lithium metal composite oxide powder and the tungsten-added material are mixed. The solvent is added and mixed in the range of 10 to 200 ml, more preferably 30 to 100 ml per 100 g of the lithium metal composite oxide powder. If it is less than 10 ml, uniform mixing becomes difficult, and if it exceeds 200 ml, it takes time to dry, which is not preferable.

A general mixer can be used for the mixing, for example, using a shaker mixer, a Ladyge mixer, a Julia mixer, a V blender, etc., to the extent that the skeleton of the lithium metal composite oxide particles is not destroyed. It suffices to mix well with tungsten oxide or lithium tungstate.

Thereby, the fine particles of tungsten oxide or lithium tungstate can be uniformly distributed on the surface of the lithium metal composite oxide powder.

In the production method of the present invention, in order to improve the battery capacity and safety of the positive electrode material, the lithium metal composite oxide powder can be further washed with water before the mixing step.

This washing with water may be carried out by a known method and conditions, and may be carried out within a range in which lithium is not excessively eluted from the lithium metal composite oxide powder and the battery characteristics are not deteriorated.

When washed with water, it can be dried and then mixed with tungsten oxide or lithium tungstate, or it can be mixed with tungsten oxide or lithium tungstate without drying by solid-liquid separation and then dried. It may be.

Further, the drying may be carried out by a known method and conditions as long as the battery characteristics of the lithium metal composite oxide are not deteriorated.

(Lithium-ion secondary battery)
The lithium ion secondary battery of the present embodiment (hereinafter, also referred to as “secondary battery”) can have a positive electrode containing the above-mentioned positive electrode active material.

Hereinafter, one configuration example of the secondary battery of the present embodiment will be described for each component. The secondary battery of the present embodiment includes, for example, a positive electrode, a negative electrode, and a non-aqueous electrolyte, and is composed of the same components as a general lithium ion secondary battery. The embodiment described below is merely an example, and the lithium ion secondary battery of the present embodiment is implemented in a form in which various changes and improvements are made based on the knowledge of those skilled in the art, including the following embodiment. can do. Moreover, the use of the secondary battery is not particularly limited.

(Positive electrode)
The positive electrode of the secondary battery of the present embodiment may contain the above-mentioned positive electrode active material.

An example of a method for manufacturing a positive electrode will be described below. First, the above-mentioned positive electrode active material (powder), conductive material and binder (binder) are mixed to form a positive electrode mixture, and if necessary, activated carbon or a solvent for viscosity adjustment or the like is added. This can be kneaded to prepare a positive electrode mixture paste.

Since the mixing ratio of each material in the positive electrode mixture is a factor that determines the performance of the lithium ion secondary battery, it can be adjusted according to the application. The mixing ratio of the materials can be the same as that of the positive electrode of a known lithium ion secondary battery. For example, when the total mass of the solid content of the positive electrode mixture excluding the solvent is 100% by mass, the positive electrode active material is used. The conductive material can be contained in a proportion of 60% by mass or more and 95% by mass or less, the conductive material in an amount of 1% by mass or more and 20% by mass or less, and the binder in an amount of 1% by mass or more and 20% by mass or less.

The obtained positive electrode mixture paste is applied to the surface of a current collector made of aluminum foil, for example, and dried to disperse the solvent to prepare a sheet-shaped positive electrode. If necessary, pressurization can be performed by a roll press or the like in order to increase the electrode density. The sheet-shaped positive electrode thus obtained can be cut into an appropriate size according to the target battery and used for manufacturing the battery.

As the conductive material, for example, graphite (natural graphite, artificial graphite, expanded graphite, etc.), carbon black materials such as acetylene black and Ketjen black (registered trademark), and the like can be used.

As a binder, it plays a role of binding active material particles. For example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluororubber, ethylene propylene diene rubber, styrene butadiene, cellulose-based One or more kinds selected from resin, polyacrylic acid and the like can be used.

If necessary, a positive electrode active material, a conductive material, or the like can be dispersed, and a solvent that dissolves the binder can be added to the positive electrode mixture. Specifically, as the solvent, an organic solvent such as N-methyl-2-pyrrolidone can be used. In addition, activated carbon can be added to the positive electrode mixture in order to increase the electric double layer capacity.

The method for producing the positive electrode is not limited to the above-described example, and other methods may be used. For example, it can be produced by press-molding a positive electrode mixture and then drying it in a vacuum atmosphere.

(Negative electrode)
As the negative electrode, metallic lithium, a lithium alloy, or the like can be used. For the negative electrode, a binder is mixed with a negative electrode active material that can occlude and desorb lithium ions, and a paste-like negative electrode mixture is added to a suitable solvent on the surface of a metal leaf current collector such as copper. It may be coated, dried, and if necessary, compressed to increase the electrode density.

As the negative electrode active material, for example, a calcined organic compound such as natural graphite, artificial graphite and phenol resin, and a powdered carbon substance such as coke can be used. In this case, a fluororesin such as PVDF can be used as the negative electrode binder as in the case of the positive electrode, and an organic such as N-methyl-2-pyrrolidone can be used as the solvent for dispersing these active substances and the binder. A solvent can be used.

(Separator)
A separator can be sandwiched between the positive electrode and the negative electrode, if necessary. As the separator, a positive electrode and a negative electrode are separated to retain an electrolyte, and a known one can be used. For example, a thin film such as polyethylene or polypropylene, which has a large number of fine pores, may be used. it can.

(Non-aqueous electrolyte)
As the non-aqueous electrolyte, for example, a non-aqueous electrolyte solution can be used.

As the non-aqueous electrolyte solution, for example, a solution in which a lithium salt as a supporting salt is dissolved in an organic solvent can be used. Further, as the non-aqueous electrolyte solution, one in which a lithium salt is dissolved in an ionic liquid may be used. The ionic liquid is a salt that is composed of cations and anions other than lithium ions and is liquid even at room temperature.

Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and trifluoropropylene carbonate, chain carbonates such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate and dipropyl carbonate, and tetrahydrofuran and 2-methyltetrahydrofuran. And one selected from ether compounds such as dimethoxyethane, sulfur compounds such as ethylmethyl sulfone and butane sulton, phosphorus compounds such as triethyl phosphate and trioctyl phosphate may be used alone, or two or more thereof may be mixed. It can also be used.

As the supporting salt, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiN (CF ₃ SO ₂ ) ₂ , and a composite salt thereof can be used. Further, the non-aqueous electrolyte solution may contain a radical scavenger, a surfactant, a flame retardant and the like.

Moreover, you may use a solid electrolyte as a non-aqueous electrolyte. The solid electrolyte has a property of being able to withstand a high voltage. Examples of the solid electrolyte include an inorganic solid electrolyte and an organic solid electrolyte.

Examples of the inorganic solid electrolyte include oxide-based solid electrolytes and sulfide-based solid electrolytes.

The oxide-based solid electrolyte is not particularly limited, and for example, one containing oxygen (O) and having lithium ion conductivity and electron insulating property can be preferably used. Examples of the oxide-based solid electrolyte include lithium phosphate (Li ₃ PO ₄ ), Li ₃ PO ₄ N _X , LiBO ₂ N _X , LiNbO ₃ , LiTaO ₃ , Li ₂ SiO ₃ , Li ₄ SiO _4- Li ₃ PO ₄ , Li ₄ SiO _4- Li ₃ VO ₄ , Li ₂ O-B ₂ O _3- P ₂ O ₅ , Li ₂ O-SiO ₂ , Li ₂ O-B ₂ O _3- ZnO, Li _{1 + X} Al _X Ti _2-X (PO ₄ ) ₃ (0 ≦ X ≦ 1), Li _{1 + X} Al _X Ge _2-X (PO ₄ ) ₃ (0 ≦ X ≦ 1), LiTi ₂ (PO ₄ ) ₃ , Li _3X La _{2 / 3-X} TiO ₃ (0 ≤ X ≤ 2/3), Li ₅ La ₃ Ta ₂ O ₁₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₆ BaLa ₂ Ta ₂ O ₁₂ , Li _3.6 Si _0.6 One or more types selected from P _0.4 O _{4 and the} like can be used.

The sulfide-based solid electrolyte is not particularly limited, and for example, one containing sulfur (S) and having lithium ion conductivity and electron insulating property can be preferably used. Examples of the sulfide-based solid electrolyte include Li ₂ S-P ₂ S ₅ , Li ₂ S-SiS ₂ , LiI-Li ₂ S-SiS ₂ , LiI-Li ₂ S-P ₂ S ₅ , LiI-Li _{2. S-B 2 S 3, Li} 3 PO 4 -Li 2 S-Si 2 S, Li 3 PO 4 -Li 2 S-SiS 2, LiPO 4 -Li 2 S-SiS, LiI-Li 2 S-P 2 O One or more types selected from ₅ , LiI-Li ₃ PO _4- P ₂ S _{5 and the} like can be used.

As the inorganic solid electrolyte, an electrolyte other than the above may be used, and for example, Li ₃ N, LiI, Li ₃ N-LiI-LiOH or the like may be used.

The organic solid electrolyte is not particularly limited as long as it is a polymer compound exhibiting ionic conductivity, and for example, polyethylene oxide, polypropylene oxide, copolymers thereof and the like can be used. Further, the organic solid electrolyte may contain a supporting salt (lithium salt).

(Shape and configuration of secondary battery)
The lithium ion secondary battery of the present embodiment described as described above can have various shapes such as a cylindrical shape and a laminated shape. Regardless of which shape is adopted, if the secondary battery of the present embodiment uses a non-aqueous electrolyte solution as the non-aqueous electrolyte, the positive electrode and the negative electrode are laminated via a separator to form an electrode body. The obtained electrode body is impregnated with a non-aqueous electrolyte solution, and a lead for collecting current is provided between the positive electrode current collector and the positive electrode terminal communicating with the outside, and between the negative electrode current collector and the negative electrode terminal communicating with the outside. It can be connected using such as, and the structure can be sealed in the battery case.

As described above, the secondary battery of the present embodiment is not limited to the form in which the non-aqueous electrolyte solution is used as the non-aqueous electrolyte. For example, the secondary battery using a solid non-aqueous electrolyte, that is, all. It can also be a solid-state battery. In the case of an all-solid-state battery, the configurations other than the positive electrode active material can be changed as needed.

The secondary battery of the present embodiment can suppress the generation of gas and is excellent in storage stability. Therefore, it can be particularly preferably used for a battery that is easily affected by gas generation, such as a laminated battery. Further, since the secondary battery of the present embodiment can stabilize the battery characteristics by suppressing the generation of gas, it can be suitably used for batteries other than the laminated type.

The secondary battery of the present embodiment can be used for various purposes, but since it can be a high-capacity, high-output secondary battery, for example, a small portable electronic device (notebook) that always requires a high capacity. It is suitable as a power source for (type personal computers, mobile phone terminals, etc.), and is also suitable as a power source for electric vehicles that require high output.

Further, since the secondary battery of the present embodiment can be miniaturized and has a high output, it is suitable as a power source for an electric vehicle whose mounting space is restricted. The secondary battery of the present embodiment can be used not only as a power source for an electric vehicle driven by purely electric energy, but also as a power source for a so-called hybrid vehicle used in combination with a combustion engine such as a gasoline engine or a diesel engine. it can.

(Characteristic)
The non-aqueous electrolyte secondary battery using the positive electrode active material of the present invention has a high capacity and a high output.

A non-aqueous electrolyte secondary battery using a positive electrode active material obtained in a particularly preferable form can obtain a high initial discharge capacity of 165 mAh / g or more and a low positive electrode resistance, for example, when used for the positive electrode of a 2032 type coin battery. It has a higher capacity and higher output. In addition, it has high thermal stability and is also excellent in safety.

The method for measuring the positive electrode resistance in the present invention is illustrated below.

When the frequency dependence of the battery reaction is measured by the general AC impedance method as an electrochemical evaluation method, the Nyquist diagram based on the solution resistance, the negative electrode resistance and the negative electrode capacitance, and the positive electrode resistance and the positive electrode capacitance is shown in FIG. Obtained like this.

The battery reaction at this electrode consists of a resistance component due to charge transfer and a capacitance component due to the electric double layer. When these are represented by an electric circuit, it becomes a parallel circuit of resistance and capacitance, and the battery as a whole is a solution resistance, a negative electrode, and a positive electrode in parallel. It is represented by an equivalent circuit in which the circuits are connected in series.

Fitting calculation can be performed on the Nyquist diagram measured using this equivalent circuit, and each resistance component and capacitance component can be estimated.

The positive electrode resistance is equal to the diameter of the resulting semicircle on the low frequency side of the Nyquist diagram.

From the above, the positive electrode resistance can be estimated by measuring the AC impedance of the manufactured positive electrode and calculating the fitting of the obtained Nyquist diagram with an equivalent circuit.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. As described below, a battery was manufactured using the positive electrode active material prepared in each Example and Comparative Example, and the evaluation was carried out. First, a battery manufacturing method and an evaluation method will be described.

(Battery manufacturing and evaluation)
A 2032 type coin-type battery 10 (hereinafter referred to as a coin-type battery) shown in FIG. 2 was used for the evaluation of the positive electrode active material.

As shown in FIG. 2, the coin-type battery 10 is composed of a case 11 and an electrode 12 housed in the case 11.

The case 11 has a positive electrode can 11a that is hollow and has one end opened, and a negative electrode can 11b that is arranged in the opening of the positive electrode can 11a. When the negative electrode can 11b is arranged in the opening of the positive electrode can 11a, , A space for accommodating the electrode 12 is formed between the negative electrode can 11b and the positive electrode can 11a.

The electrode 12 is composed of a positive electrode 12a, a separator 12c, and a negative electrode 12b, and is laminated so as to be arranged in this order. The positive electrode 12a contacts the inner surface of the positive electrode can 11a via a current collector 13, and the negative electrode 12b collects. It is housed in the case 11 so as to come into contact with the inner surface of the negative electrode can 11b via the electric body 13. A current collector 13 is also arranged between the positive electrode 12a and the separator 12c.

The case 11 is provided with a gasket 11c, and the gasket 11c fixes the relative movement of the case 11 so as to maintain a non-contact state between the positive electrode can 11a and the negative electrode can 11b. Further, the gasket 11c also has a function of sealing the gap between the positive electrode can 11a and the negative electrode can 11b to hermetically and liquidally shut off the inside and the outside of the case 11.

The coin-type battery 10 shown in FIG. 2 above was manufactured as follows.

First, 52.5 mg of the positive electrode active material for a lithium ion secondary battery, 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE) prepared in the following Examples and Comparative Examples were mixed, and the diameter was 11 mm at a pressure of 100 MPa. , Press-molded to a thickness of 100 μm to prepare a positive electrode 12a. The prepared positive electrode 12a was dried in a vacuum dryer at 120 ° C. for 12 hours.

Using the positive electrode 12a, the negative electrode 12b, the separator 12c, and the electrolytic solution, the coin-type battery 10 described above was produced in a glove box having an Ar atmosphere with a dew point controlled at −80 ° C.

For the negative electrode 12b, a graphite powder having an average particle diameter of about 20 μm punched into a disk shape having a diameter of 14 mm and a negative electrode sheet coated with polyvinylidene fluoride on a copper foil were used.

A polyethylene porous membrane having a film thickness of 25 μm was used for the separator 12c. As the electrolytic solution, an equal amount mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1M LiClO ₄ as a supporting electrolyte (manufactured by Tomiyama Pure Chemical Industries, Ltd.) was used.

The initial discharge capacity and cycle characteristics indicating the performance of the manufactured coin-type battery 10 were evaluated as follows.

The initial discharge capacity is the cutoff voltage 4 with the current density for the positive electrode set to 0.1 mA / cm ² after the open circuit voltage OCV (Open Circuit Voltage) stabilizes after leaving the coin-type battery 10 for about 24 hours after manufacturing it. The initial discharge capacity was defined as the capacity when the battery was charged to 3 V, paused for 1 hour, and then discharged to a cutoff voltage of 3.0 V.

In addition, the cycle characteristics of the obtained coin-type battery were evaluated as a battery evaluation. The cycle characteristics were evaluated by measuring the capacity retention rate after 200 cycles of charging and discharging. Specifically, the produced coin-type battery is charged to a cutoff voltage of 4.3 V in a constant temperature bath held at 25 ° C. with a current density of 0.3 mA / cm ² , and cut after a one-hour rest. After conditioning to repeat the cycle of discharging to an off voltage of 3.0 V for 5 cycles, the current density is set to 2.0 mA / cm ² and the cut-off voltage is charged to 4.3 V in a constant temperature bath maintained at 60 ° C. After a one-hour rest, the cycle of discharging to a cutoff voltage of 3.0 V was repeated for 200 cycles, and the discharge capacity of each cycle was measured for evaluation.

Then, the capacity retention rate, which is the ratio obtained by dividing the discharge capacity obtained in the first cycle after conditioning of the coin-type battery by the discharge capacity obtained in the cycle 200 cycles after conditioning, is only the lithium metal composite oxide. When it was higher than the case evaluated in, it was judged that the cycle characteristics were excellent.

In this example, each sample of special grade reagent manufactured by Wako Pure Chemical Industries, Ltd. was used for producing the positive electrode active material and the secondary battery.

Hereinafter, each condition of Examples and Comparative Examples will be described.

Lithium metal composite represented by Li _1.02 Ni _0.94 Co _0.008 Al _0.052 O ₂ obtained by a known technique of mixing and firing an oxide containing nickel as a main component and lithium hydroxide. The oxide powder was washed with water under the condition of 1.5 g / ml to prepare a base material for the positive electrode material.

The composition was analyzed by the ICP method, and the average particle size was evaluated using the volume integrated average value in the laser diffraction scattering method.

To 20 g of the produced lithium metal composite oxide powder, 0.09 g of lithium tungstate (Li ₂ WO ₄ ) powder having a particle size of 0.01 μm was added as a tungsten-added material, and a shaker mixer device (Willie e-Baccofen (WAB)) was added. ) TURBULA Type T2C) was used to sufficiently mix the mixture to obtain a mixture of lithium tungstenate and lithium metal composite oxide powder, which was used as a positive electrode material.

When the tungsten content in this positive electrode material was analyzed by the ICP method, it was confirmed that the composition was 0.15 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M.

From this, it was also confirmed that the composition of the positive electrode material was equivalent to that of the mixture of the lithium tungstate powder and the lithium metal composite oxide powder.
(Battery evaluation)
The battery characteristics of the coin-type battery 1 having a positive electrode formed by using the obtained positive electrode material were evaluated.

The initial discharge capacity in Example 1 was 217.9 mAh / g, the discharge capacity after 200 cycles was 138.6 mAh / g, and the capacity retention rate before and after the cycle was 63.6%.

Hereinafter, for Examples 2 to 6 and Comparative Examples 1 and 2, only the substances and conditions changed from Example 1 are shown. Table 1 shows the evaluation values of the initial discharge capacity and the cycle characteristics of Examples 1 to 6 and Comparative Examples 1 and 2.

A coin-type battery using a positive electrode material for a lithium ion secondary battery produced in the same manner as in Example 1 except that tungsten oxide WO ₃ having a particle size of 0.01 μm was added to a lithium metal composite oxide powder as a base material. Was prepared, and the battery was evaluated.

Using the positive electrode material for a lithium ion secondary battery produced in the same manner as in Example 1 except that lithium Li ₄ WO ₅ tartrate having a particle size of 0.01 μm was added to the lithium metal composite oxide powder as the base material. A coin-type battery was manufactured and the battery was evaluated.

Using the positive electrode material for a lithium ion secondary battery produced in the same manner as in Example 1 except that lithium lithium tantistate Li ₂ WO ₄ having a particle size of 0.09 μm was added to the lithium metal composite oxide powder as the base material. A coin-type battery was manufactured and the battery was evaluated.

Lithium ions produced in the same manner as in Example 1 except that the amount of lithium sulfonate Li ₂ WO ₄ added was 1.5 g (corresponding to 2.5 at% with respect to the total of nickel, cobalt and the added element M). A coin-type battery was manufactured using a positive electrode material for a secondary battery, and the battery was evaluated.
(Comparative Example 1)
A coin-type battery was prepared by using the lithium metal composite oxide powder used as the base material in Example 1 as the positive electrode active material (positive electrode material), and the battery was evaluated.
(Comparative Example 2)
Except that the addition of lithium tungstate particle size 10μm Li ₂ WO ₄ in the lithium metal composite oxide powder as a base material in Example 1, a positive electrode material for a lithium ion secondary battery manufactured by the same manner as in Example 1 A coin-type battery was manufactured using the battery, and the battery was evaluated.

Lithium ions produced in the same manner as in Example 1 except that the amount of lithium sulfonate Li ₂ WO ₄ added was 2.1 g (corresponding to 3.5 at% with respect to the total of nickel, cobalt and the added element M). A coin-type battery was manufactured using a positive electrode material for a secondary battery, and the battery was evaluated.

The measurement results of Examples 1 to 6 and Comparative Examples 1 and 2 are summarized in Table 1.

Lithium metal composite represented by Li _1.02 Ni _0.94 Co _0.008 Al _0.052 O ₂ obtained by a known technique of mixing and firing an oxide containing nickel as a main component and lithium hydroxide. The oxide powder was washed with water under the condition of 1.5 g / ml to prepare a base material for the positive electrode material.

The composition was analyzed by the ICP method, and the average particle size was evaluated using the volume integrated average value in the laser diffraction scattering method.

To 20 g of the produced lithium metal composite oxide powder, 10 ml of ethanol as an organic solvent and 0.18 g of lithium tungstate (Li ₄ WO ₅ ) powder having a particle size of 0.01 μm as a tungsten-added material were added, and further, a shaker mixer device (Shaker mixer device ( It was thoroughly mixed using TURBULA Type T2C manufactured by Willy et Bacoffen (WAB), dried at 90 ° C. for 10 minutes, and then a mixture of lithium tungstate and lithium metal composite oxide powder was obtained as a positive electrode material. ..

When the tungsten content in this positive electrode material was analyzed by the ICP method, it was confirmed that the composition was 0.3 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M.

From this, it was also confirmed that the composition of the positive electrode material was equivalent to that of the mixture of the lithium tungstate powder and the lithium metal composite oxide powder.
(Battery evaluation)
The battery characteristics of the coin-type battery 1 having a positive electrode formed by using the obtained positive electrode material were evaluated.

The initial discharge capacity in Example 7 was 212.4 mAh / g, the discharge capacity after 200 cycles was 169.0 mAh / g, and the capacity retention rate before and after the cycle was 79.6%.

A coin-type battery 1 was produced using the positive electrode material for a lithium ion secondary battery produced in the same manner as in Example 7 except that methanol was used as the organic solvent to be added, and the battery was evaluated.

A coin-type battery 1 was produced using the positive electrode material for a lithium ion secondary battery produced in the same manner as in Example 7 except that acetonitrile was used as the organic solvent to be added, and the battery was evaluated.

A coin-type battery 1 was prepared using the positive electrode material for a lithium ion secondary battery prepared in the same manner as in Example 7 except that N-methyl-2-pyrrolidinone (NMP) was added to the organic solvent, and the battery was evaluated. Was done.

A positive electrode mixture obtained by mixing 52.5 mg of the positive electrode material obtained by the method of Example 7 with 10 ml of N-methyl-2-pyrrolidinone (NMP), 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE). A coin-type battery 1 was produced and the battery was evaluated by the same method as in Example 7.

(Comparative Example 3)
To the lithium metal composite oxide powder used as the base material in Example 7, N-methyl-2-pyrrolidinone (NMP) was used as an organic solvent to be added, and lithium tungstate Li ₄ WO ₅ having a particle size of 0.01 μm was added. A coin-type battery 1 was produced using the positive electrode material for a lithium ion secondary battery produced in the same manner as in Example 7 except for the above, and the battery was evaluated.

Table 2 summarizes the results of Examples 7 to 11 and Comparative Example 3 described above.

（評価）
実施例１〜１１の正極材料は、本発明に従って製造されたため、この正極材料を用いたリチウムイオン二次電池は、初期放電容量が高く、２００サイクル後の放電容量維持率も高いものとなっており、優れた特性を有した電池が得られることが確認された。

(Evaluation)
Since the positive electrode materials of Examples 1 to 11 were manufactured according to the present invention, the lithium ion secondary battery using this positive electrode material has a high initial discharge capacity and a high discharge capacity retention rate after 200 cycles. It was confirmed that a battery having excellent characteristics can be obtained.

In particular, since the positive electrode materials of Examples 7 to 11 contain an organic solvent having excellent wettability with the positive electrode active material, both the initial discharge capacity and the discharge capacity retention rate after 200 cycles are good.

In Comparative Example 1, since lithium tungstate is not mixed, the cycle characteristics are low.

In Comparative Example 2, since the particle size of the tungsten-added material lithium tungstate Li ₂ WO ₄ was 10 μm, which was out of the range of the present invention, the cycle characteristics were low as in Comparative Example 1.

Further, in Comparative Example 3, since only NMP having poor wettability with the positive electrode active material was used as the organic solvent, the cycle characteristics were lower than those using the organic solvent having excellent wettability.

In Example 11, an organic solvent having good wettability with powder is mixed to form a positive electrode material, and then N-methyl-2-pyrrolidinone (NMP), which is a solvent that dissolves the binder together with a conductive material and a binder, is used. It can be seen that good characteristics are obtained even when) is mixed.

From the above results, it can be confirmed that the lithium ion secondary battery using the positive electrode material of the present invention has a high initial discharge capacity and high cycle characteristics, and is a battery having excellent characteristics.

The lithium-ion secondary battery of the present invention is suitable as a power source for small portable electronic devices (notebook personal computers, mobile phone terminals, etc.) that always require high capacity, and is suitable for electric vehicle batteries that require high output. Is also suitable.

Further, the lithium ion secondary battery of the present invention has excellent safety, can be miniaturized and has a high output, and is therefore suitable as a power source for an electric vehicle whose mounting space is restricted.

The present invention can be used not only as a power source for an electric vehicle driven by purely electric energy, but also as a power source for a so-called hybrid vehicle used in combination with a combustion engine such as a gasoline engine or a diesel engine.

1 Coin type battery 2 Case 2a Positive electrode can 2b Negative electrode can 2c Gasket 3 Electrode 3a Positive electrode 3b Negative electrode 3c Separator

Claims (15)

Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by (species element) and tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tungstate having a particle size of 0.01 to 0.09 μm. A method for producing a positive electrode material for a lithium ion secondary battery, which comprises mixing an additive material with the additive material. Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by the element of the species), at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, and a particle size of 0.01 to 0. A method for producing a positive electrode material for a lithium ion secondary battery, which comprises mixing 09 μm tungsten oxide or a tungsten-added material of lithium tartrate having a particle size of 0.01 to 0.09 μm. The production method according to claim 1 or 2, wherein the step of washing the lithium metal composite oxide powder with water before mixing the lithium metal composite oxide powder and the tungsten-added material is included. The amount of tungsten contained in the positive electrode material is 0.1 to 3.0 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M contained in the lithium metal composite oxide powder. The manufacturing method according to any one of claims 1 to 3. Claims 1 to 1, wherein the tungsten-added material is tungsten oxide of WO ₃ , or at least one lithium tungstate selected from Li ₂ WO ₄ , Li ₄ WO ₅ , and Li ₆ W ₂ O ₉ . The production method according to any one of 4. Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by (species element) and tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tungstate having a particle size of 0.01 to 0.09 μm. A positive electrode material for a lithium ion secondary battery, which comprises an additive material. Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by the element of the species), at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, and a particle size of 0.01 to 0. A positive electrode material for a lithium ion secondary battery, which comprises a tungsten oxide material having a particle size of 09 μm or lithium tartrate having a particle size of 0.01 to 0.09 μm. The positive electrode material is characterized in that the amount of tungsten is 0.1 to 3.0 atomic% with respect to the total number of atoms of nickel, cobalt and the additive element M contained in the lithium metal composite oxide powder. The positive electrode material for a lithium ion secondary battery according to claim 6 or 7. 6. Claim 6 characterized in that the tungsten-added material is tungsten oxide of WO ₃ , or at least one lithium tungstate selected from Li ₂ WO ₄ , Li ₄ WO ₅ , and Li ₆ W ₂ O _9. The positive electrode material for a lithium ion secondary battery according to any one of 8 to 8. The positive electrode material for a lithium ion secondary battery according to claim 9, wherein the tungsten-added material is lithium tungstate containing Li ₄ WO ₅ when it is lithium tungstate. Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by (species element), N-methyl-2-pyrrolidinone, tungsten oxide having a particle size of 0.01 to 0.09 μm or a particle size of 0.01 to 0 A positive electrode material for a lithium ion secondary battery, which comprises a tungsten-added material of .09 μm lithium tartrate. A lithium ion secondary battery comprising a positive electrode containing the positive electrode material for a lithium ion secondary battery according to any one of claims 6 to 11. Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least 1 selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder contained in the atomic number ratio represented by the seed element) and tungsten oxide having a particle size of 0.01 to 0.09 μm or lithium tungstate having a particle size of 0.01 to 0.09 μm are added. Production of a positive electrode mixture for a lithium ion secondary battery, which comprises mixing a conductive material and a binder and N-methyl-2-pyrrolidinone, a solvent that dissolves the binder, in a mixture with the material. Method. Lithium (Li), nickel (Ni), cobalt (Co), and element M are composed of Li: Ni: Co: M = z: (1-xy): x: y (where 0.97 ≦ z). ≤1.20, 0≤x <0.01, 0≤y≤0.10, 0≤x + y≤0.10, M is at least one selected from Mn, V, Mg, Mo, Nb, Ti and Al. Lithium metal composite oxide powder containing an atomic number ratio represented by (species element), at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, and a particle size of 0.01 to 0. In a mixture of 09 μm tungsten oxide or a lithium tungsten-added material having a particle size of 0.01 to 0.09 μm,
A method for producing a positive electrode mixture for a lithium ion secondary battery, which comprises mixing a conductive material and a binder with N-methyl-2-pyrrolidinone, a solvent that dissolves the binder. A lithium ion secondary battery comprising a positive electrode containing a positive electrode mixture for a lithium ion secondary battery according to the production method according to claim 13 or 14.

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