JP2016225277A - Positive electrode material for nonaqueous electrolyte secondary battery and method of producing the same, and nonaqueous electrolyte secondary battery using the positive electrode material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive electrode material for a nonaqueous electrolyte secondary battery, with which both of high capacity and high output can be obtained when the positive electrode material is used for a positive electrode.SOLUTION: A method for manufacturing a positive electrode material for a nonaqueous electrolyte secondary battery is characterized in that lithium metal composite oxide powder, at least one organic solvent selected from among ethanol, methanol, propanol, butanol, and acetonitrile, and a tungsten additive material of a tungsten oxide with a grain size of 0.01-0.09 μm or lithium tungstate with a grain size of 0.01-0.09 μm are mixed, the lithium metal composite oxide powder being represented by general formula LiNiCoMO(where, 0.01≤x≤0.35, 0≤y≤0.35, 0.97≤z≤1.20, and M represents an additive element and is at least one element selected from among Mn, V, Mg, Mo, Nb, Ti and Al) and comprising a primary particle and a secondary particle formed by the aggregation of the primary particles.SELECTED DRAWING: None

Description

  The present invention relates to a positive electrode material for a non-aqueous electrolyte secondary battery, a manufacturing method thereof, and a non-aqueous electrolyte secondary battery using the positive electrode material.

In recent years, with the widespread use of portable electronic devices such as mobile phones and notebook computers, development of small and lightweight non-aqueous electrolyte secondary batteries with high energy density is strongly desired, and electric vehicles including hybrid vehicles Development of a high-power secondary battery as a battery for power generation is also strongly desired.
As a secondary battery satisfying such requirements, there is a lithium ion secondary battery.

In this lithium ion secondary battery, a material from which lithium can be desorbed and inserted is used for the active material of the negative electrode and the positive electrode.
Such lithium ion secondary batteries are currently being actively researched and developed. Among them, lithium ion secondary batteries using a layered or spinel type lithium metal composite oxide as a positive electrode material are among them. Since a high voltage of 4V class can be obtained, practical use is progressing as a battery having a high energy density.

Examples of active material materials that have been proposed so far include lithium cobalt composite oxide (LiCoO ₂ ) that is relatively easy to synthesize, lithium nickel composite oxide (LiNiO ₂ ) using nickel that is less expensive than cobalt, lithium Examples thereof include nickel cobalt manganese composite oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), lithium manganese composite oxide (LiMn ₂ O ₄ ) using manganese, and the like.
Of these, lithium nickel composite oxide and lithium nickel cobalt manganese composite oxide are attracting attention as materials with good cycle characteristics, low resistance and high output, and excellent battery characteristics. Low resistance is regarded as important.

Addition of foreign elements is used as a method for improving such battery characteristics, and transition metals capable of taking high numbers such as W, Mo, Nb, Ta and Re are particularly useful.
For example, Patent Document 1 proposes a positive electrode material that can provide high capacity and high output by mixing lithium metal composite oxide powder and lithium tungstate as a positive electrode material of a non-aqueous electrolyte secondary battery. Yes. Further, in Patent Document 2, it is said that the same effect can be obtained by mixing lithium metal composite oxide powder and tungsten oxide.
However, in either case, the effect is obtained by uniformly dispersing the tungsten compound in the positive electrode material. However, when the amount of mixing increases, the instability of uniformly covering the surface of the active material with lithium tungstate is not stable. There is a risk that it will increase, and it has been difficult to stably improve lithium ion conductivity.

JP 2013-171785 A JP 2012-28313 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a positive electrode material for a non-aqueous electrolyte secondary battery that can provide a high output with a high capacity when used in a positive electrode.

  In order to solve the above-mentioned problems, the present inventors have intensively studied the influence of the lithium metal composite oxide used as the positive electrode active material for the nonaqueous electrolyte secondary battery on the powder characteristics and the positive electrode resistance of the battery. By mixing 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 through an organic solvent in consideration of wettability with the oxide powder, The inventors have found that the output characteristics can be improved by significantly reducing the positive electrode resistance, and the present invention has been completed.

That is, the manufacturing method of the first positive electrode material for a nonaqueous electrolyte secondary battery which is the invention of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35, 0 ≦ y ≦ 0.35, 0.97 ≦ z ≦ 1.20, M is an additive element, and at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al Lithium metal composite oxide powder composed of primary particles and secondary particles formed by aggregation of primary particles, and tungsten oxide having a particle size of 0.01 to 0.09 μm or a particle size of 0.01 to 0 A method for producing a positive electrode material for a non-aqueous electrolyte secondary battery, characterized by mixing a tungsten additive material of 0.09 μm lithium tungstate.

Second method for manufacturing a positive electrode material for a nonaqueous electrolyte secondary battery which is the invention of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0. 35, 0 ≦ y ≦ 0.35, 0.97 ≦ z ≦ 1.20, M is an additive element, and at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al) A lithium metal composite oxide powder composed of primary particles and secondary particles composed of aggregated primary particles, at least one organic solvent selected from ethanol, methanol, propanol, butanol, and acetonitrile, A positive electrode for a non-aqueous electrolyte secondary battery, wherein a tungsten additive material of tungsten oxide having a diameter of 0.01 to 0.09 μm or lithium tungstate having a particle diameter of 0.01 to 0.09 μm is mixed. It is a fee method of manufacturing.

  The third invention of the present invention includes a step of washing the lithium metal composite oxide powder with water before mixing the lithium metal composite oxide powder and the tungsten additive material of lithium tungstate in the first and second inventions. This is a method for producing a positive electrode material for a non-aqueous electrolyte secondary battery.

  According to a fourth aspect of the present invention, the amount of tungsten contained in the positive electrode material for a non-aqueous electrolyte secondary battery in the first to third aspects is the amount of nickel, cobalt, and additive element M contained in the lithium metal composite oxide powder. It is a manufacturing method of the positive electrode material for nonaqueous electrolyte secondary batteries characterized by being 0.1-3.0 atomic% with respect to the sum total of the number of atoms.

According to a fifth aspect of the present invention, the tungsten additive material in the first to _fourth aspects is at least one selected from tungsten oxide of WO ₃ or Li ₂ WO ₄ , Li ₄ WO ₅ , Li ₆ W ₂ O _9. A method for producing a positive electrode material for a non-aqueous electrolyte secondary battery, characterized by being a lithium tungstate.

Sixth positive electrode material for a nonaqueous electrolyte secondary battery which is the invention of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35, 0.97 ≦ z ≦ 1.20, M is an additive element, and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al) Lithium metal composite oxide powder comprising primary particles and secondary particles formed by agglomeration of primary particles, and tungsten oxide having a particle size of 0.01 to 0.09 μm or tungstic acid having a particle size of 0.01 to 0.09 μm A positive electrode material for a non-aqueous electrolyte secondary battery comprising a mixture of lithium and a tungsten additive material.

Seventh aspect of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is an additive element, and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), and the primary particles and the primary particles are aggregated. Lithium metal composite oxide powder composed of the formed secondary particles, at least one organic solvent selected from ethanol, methanol, propanol, butanol and acetonitrile, and tungsten oxide having a particle size of 0.01 to 0.09 μm, or A positive electrode material for a non-aqueous electrolyte secondary battery, comprising a mixture of lithium tungstate having a particle size of 0.01 to 0.09 μm and a tungsten additive material.

  In an eighth aspect of the present invention, the amount of tungsten contained in the positive electrode material for a non-aqueous electrolyte secondary battery in the sixth and seventh aspects is nickel, cobalt, and additive element M contained in the lithium metal composite oxide powder. The positive electrode material for a non-aqueous electrolyte secondary battery is characterized in that the number of tungsten atoms is 0.1 to 3.0 atomic% with respect to the total number of atoms.

According to a ninth aspect of the present invention, the tungsten-added material in the sixth to eighth aspects is at least one selected from tungsten oxide of WO ₃ or Li ₂ WO ₄ , Li ₄ WO ₅ , Li ₆ W ₂ O _9. The tenth aspect of the invention is a lithium tungstate containing Li ₄ WO ₅ when the tungsten-added material in the ninth aspect of the invention is lithium tungstate. The positive electrode material for a non-aqueous electrolyte secondary battery.

Eleventh aspect of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is an additive element, and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), and is formed by agglomeration of primary particles and primary particles. Lithium metal composite oxide powder comprising secondary particles, N-methyl-2-pyrrolidinone, 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 non-aqueous electrolyte secondary battery, comprising a mixture with a tungsten additive material.

  A twelfth aspect of the present invention is a nonaqueous electrolyte secondary battery comprising a positive electrode including the positive electrode material for a nonaqueous electrolyte secondary battery according to the sixth to eleventh aspects of the present invention.

Thirteenth aspect of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is an additive element, and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), and the primary particles and the primary particles are aggregated. A mixture of the lithium metal composite oxide powder composed of the secondary particles and tungsten-added material of 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 mixture for a non-aqueous electrolyte secondary battery, comprising mixing a conductive material and a binder, and N-methyl-2-pyrrolidinone as a solvent for dissolving the binder.

Fourteenth aspect of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is an additive element, and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), and is formed by aggregation of primary particles and primary particles. Lithium metal composite oxide powder comprising secondary particles, at least one organic solvent selected from ethanol, methanol, propanol, butanol and acetonitrile, tungsten oxide having a particle size of 0.01 to 0.09 μm, or a particle size of 0 Conductive material, binder, and N-methyl-2-pyrrolidinone, a solvent that dissolves the binder, are mixed in a mixture of 0.01 to 0.09 μm lithium tungstate with a tungsten additive material. Which is a method for producing a positive electrode for a non-aqueous electrolyte secondary battery characterized.

  A fifteenth aspect of the present invention is a non-aqueous electrolyte secondary battery comprising a positive electrode including a positive electrode mixture for a non-aqueous electrolyte secondary battery by the production method according to the thirteenth or fourteenth aspect. .

  According to the present invention, when used as a positive electrode material of a battery, a positive electrode active material for a non-aqueous electrolyte secondary battery that can realize a high-capacity and high-output non-aqueous electrolyte secondary battery is obtained, and its manufacture The method is easy and suitable for production on an industrial scale, and its industrial value is extremely high.

It is a schematic explanatory drawing of the measurement example of impedance evaluation, and the equivalent circuit used for analysis. It is a schematic sectional drawing of the coin-type battery 1 used for 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 manufacturing method thereof 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 nonaqueous electrolyte secondary battery of the present invention have the general formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35 0.97 ≦ z ≦ 1.20, where M is an additive element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al). Tungsten addition of lithium metal composite oxide powder composed of secondary particles formed by aggregation of particles 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 It is a mixture of materials.
In the present invention, a high charge / discharge capacity can be obtained by using the lithium metal composite oxide powder represented by the above general formula as the positive electrode active material as a base material. By mixing a tungsten-added material of 0.01 to 0.09 μm tungsten oxide or lithium tungstate having a particle size of 0.01 to 0.09 μm, the output characteristics are improved while maintaining the charge / discharge capacity.

Normally, when the surface of the positive electrode active material is completely covered with a different compound, the movement (intercalation) of lithium ions is greatly restricted, and as a result, the advantage of the high capacity of the lithium composite oxide is eliminated. Will be. In addition, dissolving different elements in the lithium composite oxide tends to cause a decrease in capacity.
On the other hand, since a compound having high lithium ion conductivity has an effect of promoting the movement of lithium ions, the surface of the positive electrode active material can be intercalated on the surface of the positive electrode active material by coating the surface of the positive electrode active material with such a compound. However, post-treatment such as heat treatment is necessary for coating, which may lead to deterioration of excellent battery characteristics of the positive electrode active material.
Therefore, it was found that a compound having a high lithium ion conductivity was used as fine particles and the fine particles were present on the surface of the positive electrode active material, thereby eliminating the need for coating by heat treatment and improving the performance.
However, when the fine particles of the tungsten additive material are coated on the surface of the positive electrode active material, segregation of the particles easily occurs, it is difficult to obtain a uniform coating, and it is difficult to exert all the effects.
Therefore, when the cathode active material particles are coated or before coating, the tungsten additive material fine particles are mixed by mixing ethanol, which is an organic solvent that has high wettability with the cathode active material and does not adversely affect battery characteristics. It was found that segregation was suppressed and a more uniform coating was possible.

  The tungsten oxide used in the present invention is considered to be present on the surface of the active material by reacting with excess lithium on the surface of the positive electrode active material to change into lithium tungstate.

Lithium tungstate is also a compound with 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. The effect of promoting the movement of lithium and greatly reducing the positive electrode resistance is shown.
Since this lithium tungstate is present uniformly as fine particles on the surface of the active material, it acts on the electrolytic solution or the positive electrode active material, and a lithium conduction path is formed between the electrolytic solution and the positive electrode active material interface, Reduce the reaction resistance of the active material and improve the output characteristics.

When tungsten oxide with a particle size of 0.01 to 0.09 μm or lithium tungstate with a particle size of 0.01 to 0.09 μm, which is a tungsten additive material, is unevenly distributed in the positive electrode material, a lithium metal composite oxide Since the movement of lithium ions between these particles becomes non-uniform, a load is applied to specific lithium metal composite oxide particles, which tends to deteriorate cycle characteristics and increase reaction resistance.
Therefore, lithium tungstate fine particles are uniformly present on the active material surface, 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 preferable that they are distributed.

Therefore, it is necessary to uniformly disperse the tungsten oxide or lithium tungstate fine particles on the surface of the positive electrode active material and the positive electrode material, and the particle size is preferably 0.01 to 0.09 μm, More preferably, the thickness is 0.05 μm.
If the particle size is less than 0.01 μm, the pulverization cost may be excessive, which is not preferable. If the particle size exceeds 0.09 μm, lithium tungstate cannot be uniformly attached to the surface of the positive electrode material, and the reaction The resistance reduction effect may not be obtained sufficiently, which is not preferable.
As this particle size, an average particle size measured using a laser diffraction scattering method or a volume integrated average value in a microtrack is used.
In addition, when a particle diameter exceeds the said range, it is preferable to grind | pulverize before mixing.

Furthermore, 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 additive element M contained in the lithium metal composite oxide powder to be mixed. It is preferable.
This makes it possible to achieve both high charge / discharge capacity and output characteristics. However, 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 achieved. You may not get enough. On the other hand, when the amount of tungsten exceeds 3.0 atomic%, the lithium tungstate increases too much and lithium conduction between the lithium metal composite oxide and the electrolytic solution is hindered, or the amount of the active material is relatively decreased. 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 includes Li ₄ WO ₅ .
It is particularly preferable that 50% or more of Li ₄ WO ₅ is contained in lithium tungstate.
These lithium tungstates have high lithium ion conductivity, and the above effect can be sufficiently obtained by mixing with lithium metal composite oxide powder.

The amount of lithium in the lithium metal composite oxide is 0 in terms of the ratio (Li / Me) of the sum of atoms (Me) of nickel, cobalt, and additive element M in the lithium metal composite oxide to the number of atoms of lithium (Li). 97 to 1.20.
When 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 is increased, so that the output of the battery is lowered. On the other hand, 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, Li / Me is preferably set to 1.10 or less.

Co and additive element M are added in order to improve battery characteristics such as cycle characteristics and output characteristics. If x and y indicating these addition amounts exceed 0.35, they contribute to the Redox reaction. Since Ni decreases, the battery capacity decreases.
On the other hand, when x indicating the amount of Co added is less than 0.01, cycle characteristics and thermal stability cannot be obtained sufficiently. Therefore, in order to obtain a sufficient battery capacity when used in a battery, it is preferable that y indicating the amount of additive element M added is 0.15 or less.

  In addition, since it is advantageous for improving the output characteristics to increase the contact area with the electrolytic solution, lithium metal composite oxide particles composed of primary particles and secondary particles formed by aggregation of the primary particles are used. .

The positive electrode material of the present invention mixes lithium metal composite oxide powder and fine powder of tungsten oxide or lithium tungstate together with an organic solvent, whereby tungsten oxide or lithium tungstate fine particles are mixed in the surface of the positive electrode active material and the positive electrode material. Uniformly dispersed to improve the output characteristics, and the powder properties 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 positive electrode active material normally used. In addition, the lithium metal composite oxide may be obtained by a known method, and one satisfying the above composition and powder characteristics can be used.
The effects obtained by mixing the lithium metal composite oxide powder with tungsten oxide or lithium tungstate include, for example, lithium cobalt composite oxide, lithium manganese composite oxide, lithium nickel cobalt manganese composite oxide, The present invention can be applied not only to the positive electrode active material described in the present invention but also to a 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), the general formula as a cathode active material for a base material _{Li z Ni 1-x-y} Co _x M _y O ₂ (where 0.01 ≦ x ≦ 0.35, 0 ≦ y ≦ 0.35, 0.97 ≦ z ≦ 1.20, M is Mn, V, Mg, Mo, Nb, Ti And lithium metal composite oxide powder composed of primary particles and secondary particles formed by aggregation of the primary particles, ethanol, methanol, propanol, butanol, acetonitrile And at least one organic solvent selected from the group consisting of 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. To. After mixing, the positive electrode material containing a solvent may be dried or used as it is for the production of a positive electrode mixture. The drying may be performed by a known method and conditions as long as 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 to form fine particles on the surface of the positive electrode active material and to make the fine particles dispersed uniformly in the positive electrode material. In the invention, at the time of mixing the lithium metal composite oxide powder and the tungsten-added material, at least one organic compound selected from ethanol, methanol, propanol, butanol, and acetonitrile having good wettability with the lithium metal composite oxide powder. 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 preferred.
For the mixing, a general mixer can be used. For example, the shape of the lithium metal composite oxide particles is not destroyed using a shaker mixer, a Laedige mixer, a Julia mixer, a V blender, etc. Tungsten oxide or lithium tungstate may be mixed sufficiently.
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 performed by a known method and conditions as long as lithium is not excessively eluted from the lithium metal composite oxide powder and the battery characteristics are not deteriorated.
In case of washing with water, it can be either dried and mixed with tungsten oxide or lithium tungstate, or it can be mixed with tungsten oxide or lithium tungstate without drying only by solid-liquid separation and then dried. But you can.
The drying may be performed by a known method and conditions as long as the battery characteristics of the lithium metal composite oxide are not deteriorated.

(3) Non-aqueous electrolyte secondary battery The non-aqueous electrolyte secondary battery of the present invention includes a positive electrode, a negative electrode, a non-aqueous electrolyte solution, and the like, and includes the same components as those of a general non-aqueous electrolyte secondary battery.
The embodiment described below is merely an example, and the nonaqueous electrolyte secondary battery of the present invention can be variously modified based on the knowledge of those skilled in the art based on the embodiment described in the present specification. It can be implemented in an improved form. Moreover, the use of the nonaqueous electrolyte secondary battery of the present invention is not particularly limited.

(A) Positive electrode Using the positive electrode material for a non-aqueous electrolyte secondary battery according to the present invention, for example, a positive electrode of a non-aqueous electrolyte secondary battery is produced as follows.
First, a powdered positive electrode material, a conductive material, and a binder are mixed, and if necessary, a target solvent such as activated carbon and viscosity adjustment is added and kneaded to prepare a positive electrode mixture paste. The lithium metal composite oxide powder, which is a method for producing the positive electrode material of the present invention, an organic solvent having good wettability with the powder, and a fine powder of tungsten oxide or lithium tungstate are mixed simultaneously with the conductive material, A binder and a solvent may be added and kneaded to produce a positive electrode mixture paste (hereinafter referred to as a positive electrode mixture paste) for use.
Here, each mixing ratio in the positive electrode mixture paste is also an important factor that determines the performance of the non-aqueous electrolyte secondary battery.
Therefore, when the total mass of the solid content of the positive electrode mixture excluding the solvent is 100 parts by mass, the content of the positive electrode active material is 60 to 95 parts by mass, like the positive electrode of a general nonaqueous electrolyte secondary battery, It is desirable that the content of the conductive material is 1 to 20 parts by mass and the content of the binder is 1 to 20 parts by mass.

The obtained positive electrode mixture paste is applied to the surface of a current collector made of, for example, an aluminum foil and dried to disperse the solvent. If necessary, pressurization may be performed by a roll press or the like to increase the electrode density.
In this way, a sheet-like positive electrode can be produced.
The produced sheet-like positive electrode can be cut into an appropriate size or the like according to the intended battery and used for battery production. However, the method for manufacturing the positive electrode is not limited to the above-described examples, and other methods may be used.

In producing the positive electrode, as the conductive agent, for example, graphite (natural graphite, artificial graphite, expanded graphite, etc.), carbon black materials such as acetylene black, ketjen black, and the like can be used.
The binder plays a role of anchoring the active material particles. For example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluorine rubber, ethylene propylene diene rubber, styrene butadiene, cellulosic resin, polyacrylic. An acid or the like can be used.
If necessary, a positive electrode active material, a conductive material, and activated carbon are dispersed, and a solvent that dissolves the binder is added to the positive electrode mixture.
Specifically, an organic solvent such as N-methyl-2-pyrrolidone can be used as the solvent to be used. Activated carbon can be added to the positive electrode mixture in order to increase the electric double layer capacity.

(B) Negative electrode A negative electrode mixture in which a negative electrode active material capable of occluding and desorbing lithium ions is mixed with a binder and an appropriate solvent is added to the negative electrode. Is applied to the surface of a metal foil current collector such as copper, dried, and compressed to increase the electrode density as necessary.

As the negative electrode active material, for example, natural graphite, artificial graphite, a fired organic compound such as phenol resin, or a powdery carbon material such as coke can be used.
In this case, as the negative electrode binder, a fluorine-containing resin such as PVDF can be used as in the case of the positive electrode, and as a solvent for dispersing these active materials and the binder, N-methyl-2-pyrrolidone or the like can be used. Organic solvents can be used.

(C) Separator A separator is interposed between the positive electrode and the negative electrode.
The separator separates the positive electrode and the negative electrode and retains the electrolyte, and a thin film such as polyethylene or polypropylene and a film having many minute holes can be used.

(D) Non-aqueous electrolyte The non-aqueous electrolyte is obtained by dissolving a lithium salt as a supporting salt in an organic solvent.
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, ethyl methyl carbonate, and dipropyl carbonate, tetrahydrofuran, 2- One kind selected from ether compounds such as methyltetrahydrofuran and dimethoxyethane, sulfur compounds such as ethylmethylsulfone and butanesultone, phosphorus compounds such as triethyl phosphate and trioctyl phosphate, etc. are used alone or in admixture of two or more. be able to.

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

(E) Shape and configuration of non-aqueous electrolyte secondary battery The shape of the non-aqueous electrolyte secondary battery of the present invention composed of the positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte described above is cylindrical, Various types such as a laminated type can be used.
In any case, the positive electrode and the negative electrode are laminated via a separator to form an electrode body, and the obtained electrode body is impregnated with a non-aqueous electrolyte and communicated with the positive electrode current collector and the outside. The positive electrode terminal and the negative electrode current collector and the negative electrode terminal communicating with the outside are connected using a current collecting lead or the like and sealed in a battery case to complete a non-aqueous electrolyte secondary battery. .

(F) Characteristics The nonaqueous 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 more preferable form, for example, has a high initial discharge capacity of 165 mAh / g or more and a low positive electrode resistance when used for the positive electrode of a 2032 type coin battery. Higher capacity and higher output. Further, it has high thermal stability and is excellent in safety.

In addition, the measuring method of the positive electrode resistance in this invention is illustrated below.
When the frequency dependence of the battery reaction is measured by a 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 capacity, and the positive electrode resistance and the positive electrode capacity is shown in FIG. Is obtained as follows.

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 expressed as an electric circuit, it becomes a parallel circuit of resistance and capacity. It is represented by an equivalent circuit in which circuits are connected in series.
Fitting calculation is 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 semicircle on the low frequency side of the obtained Nyquist diagram.
From the above, the positive electrode resistance can be estimated by performing AC impedance measurement on the manufactured positive electrode and performing fitting calculation on the obtained Nyquist diagram with an equivalent circuit.

The performance (initial discharge capacity, positive electrode resistance) of a nonaqueous electrolyte secondary battery having a positive electrode using the positive electrode material obtained by the present invention was confirmed.
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Battery manufacture and evaluation)
For the evaluation of the positive electrode material, a 2032 type coin battery (hereinafter referred to as coin type battery 1) shown in FIG. 2 was used.
As shown in FIG. 2, the coin-type battery 1 is composed of a case 2 and an electrode 3 accommodated in the case 2.
The case 2 has a positive electrode can 2a that is hollow and open at one end, and a negative electrode can 2b that is disposed in the opening of the positive electrode can 2a. When the negative electrode can 2b is disposed in the opening of the positive electrode can 2a, A space for accommodating the electrode 3 is formed between the negative electrode can 2b and the positive electrode can 2a.

The electrode 3 includes a positive electrode 3a, a separator 3c, and a negative electrode 3b, which are stacked in this order. The positive electrode 3a contacts the inner surface of the positive electrode can 2a, and the negative electrode 3b contacts the inner surface of the negative electrode can 2b. As shown in FIG.
The case 2 includes a gasket 2c, and relative movement is fixed by the gasket 2c so as to maintain a non-contact state between the positive electrode can 2a and the negative electrode can 2b. Further, the gasket 2c also has a function of sealing a gap between the positive electrode can 2a and the negative electrode can 2b to block the inside and outside of the case 2 in an airtight and liquid tight manner.

The coin-type battery 1 used was manufactured as follows.
First, 52.5 mg of a positive electrode material for a non-aqueous electrolyte secondary battery, 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE) are mixed, press-molded to a diameter of 11 mm and a thickness of 100 μm at a pressure of 100 MPa, and the positive electrode 3a was produced.
Next, the produced positive electrode 3a was dried in a vacuum dryer at 120 ° C. for 12 hours.
Using the dried positive electrode 3a, the negative electrode 3b, the separator 3c, and the electrolyte, the coin-type battery 1 of FIG. 2 was produced in a glove box in an Ar atmosphere in which the dew point was controlled at −80 ° C.

As the negative electrode 3b, a negative electrode sheet in which graphite powder having an average particle diameter of about 20 μm punched into a disk shape with a diameter of 14 mm and polyvinylidene fluoride were applied to a copper foil was used.
Further, a polyethylene porous film having a film thickness of 25 μm was used for the separator 3c.
As the electrolytic solution, an equivalent mixed solution (manufactured by Toyama Pharmaceutical Co., Ltd.) of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1M LiClO ₄ as a supporting electrolyte was used.

The initial discharge capacity and positive electrode resistance showing the performance of the manufactured coin-type battery 1 were evaluated by the following methods.
The initial discharge capacity is left for about 24 hours after the coin-type battery 1 is manufactured. After the open circuit voltage OCV (open circuit voltage) is stabilized, the current density with respect to the positive electrode is set to 0.1 mA / cm ² and the cut-off voltage 4 The capacity when the battery was charged to 3 V, discharged after a pause of 1 hour to a cutoff voltage of 3.0 V was defined as the initial discharge capacity.

The positive resistance is measured by the AC impedance method using a frequency response analyzer and potentio galvanostat (1255B manufactured by Solartron) after charging the coin-type battery 1 at a charging potential of 4.1 V. The Nyquist plot shown in FIG. Got.
The obtained Nyquist plot is represented as the sum of the characteristic curves indicating the solution resistance, the negative electrode resistance and its capacity, and the positive electrode resistance and its capacity, so that fitting calculation is performed using an equivalent circuit based on this Nyquist plot, The value of the positive electrode resistance was calculated.
Note that, in this example, Wako Pure Chemical Industries, Ltd. reagent grade samples were used for the production of composite hydroxide, the production of the positive electrode active material, and the secondary battery.

A lithium metal composite represented by Li _1.02 Ni _0.82 Co _0.15 Al _0.03 O ₂ obtained by a known technique in which an oxide mainly composed of nickel and lithium hydroxide are mixed and fired The oxide powder was washed with water under the condition of 1.5 g / ml to obtain 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, 0.9 g of lithium tungstate (Li ₂ WO ₄ ) powder having a particle size of 0.01 μm was added as a tungsten additive material, and a shaker mixer apparatus (Willy e Bacchofen (WAB) ) TURBULA Type T2C manufactured by the company) was sufficiently mixed to obtain a mixture of lithium tungstate and lithium metal composite oxide powder, which was used as a positive electrode material.
When the tungsten content in the positive electrode material was analyzed by the ICP method, it was confirmed that the composition was 1.5 atomic% with respect to the total number of atoms of nickel, cobalt, and additive element M.
From this, it was also confirmed that the mixture of the mixture of the lithium tungstate powder and the lithium metal composite oxide powder and the composition of the positive electrode material were equivalent.

(Battery evaluation)
Battery characteristics of the coin-type battery 1 having a positive electrode formed using the obtained positive electrode material were evaluated.
The initial discharge capacity in Example 1 was 196.4 mAh / g.

  Hereinafter, for Examples 2 to 4 and Comparative Examples 1 and 2, only the substances and conditions changed from Example 1 are shown. Table 1 shows evaluation values of initial discharge capacities and positive electrode resistances of Examples 1 to 4 and Comparative Examples 1 and 2.

A coin type using a positive electrode material for a non-aqueous electrolyte 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. A battery was produced and the battery was evaluated.

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

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

(Comparative Example 1)
A coin-type battery was prepared using the lithium metal composite oxide powder used as a base material in Example 1 as a positive electrode active material (positive electrode material), and the battery was evaluated.

(Comparative Example 2)
A positive electrode material for a non-aqueous electrolyte secondary battery produced in the same manner as in Example 1, except that lithium tungstate Li ₂ WO ₄ having a particle size of 10 μm was added to the lithium metal composite oxide powder used as the base material in Example 1. A coin-type battery was produced using the battery, and the battery was evaluated.
The measurement results of Examples 1 to 4 and Comparative Examples 1 and 2 are summarized in Table 1.

A lithium metal composite represented by Li _1.02 Ni _0.82 Co _0.15 Al _0.03 O ₂ obtained by a known technique in which an oxide mainly composed of nickel and lithium hydroxide are mixed and fired The oxide powder was washed with water under the condition of 1.5 g / ml to obtain 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 prepared 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 additive material are added, and a shaker mixer device ( Mix well using TURBULA Type T2C manufactured by Willy et Bacchofen (WAB), and after drying at 90 ° C. for 10 minutes, obtain a mixture of lithium tungstate and lithium metal composite oxide powder to be 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 additive element M.
From this, it was also confirmed that the mixture of the mixture of the lithium tungstate powder and the lithium metal composite oxide powder and the composition of the positive electrode material were equivalent.

(Battery evaluation)
Battery characteristics of the coin-type battery 1 having a positive electrode formed using the obtained positive electrode material were evaluated.
The initial discharge capacity in Example 5 was 196.0 mAh / g.
Hereinafter, also about Examples 6-9 and Comparative Example 3, only the substance and conditions changed from Example 5 are shown.

  A coin-type battery 1 was produced using a positive electrode material for a non-aqueous electrolyte secondary battery produced in the same manner as in Example 5 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 a positive electrode material for a non-aqueous electrolyte secondary battery produced in the same manner as in Example 5 except that acetonitrile was used as the organic solvent to be added, and the battery was evaluated.

  A coin-type battery 1 was produced using a positive electrode material for a non-aqueous electrolyte secondary battery produced in the same manner as in Example 5 except that N-methyl-2-pyrrolidinone (NMP) was added to the organic solvent. Evaluation was performed.

  Positive electrode mixture obtained by mixing 52.5 mg of the positive electrode material obtained by the method of Example 5 with 10 ml of N-methyl-2-pyrrolidinone (NMP), 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE). After that, a coin-type battery 1 was produced by the same method as in Example 5 and battery evaluation was performed. As a result, almost the same result as in Example 5 was obtained.

(Comparative Example 3)
To the lithium metal composite oxide powder used as the base material in Example 5, N-methyl-2-pyrrolidinone (NMP) was used as an organic solvent to be added, and lithium tungstate Li ₄ WO ₅ having a particle diameter of 0.01 μm was added. The coin type battery 1 was produced using the positive electrode material for nonaqueous electrolyte secondary batteries produced in the same manner as in Example 5, and the battery was evaluated.
The results of Examples 5 to 9 and Comparative Example 3 are summarized in Table 2.

(Evaluation)
Since the positive electrode materials of Examples 1 to 9 were manufactured according to the present invention, the non-aqueous electrolyte secondary battery using this positive electrode material had high initial discharge capacity and low positive electrode resistance, and excellent characteristics. It was confirmed that a battery having
In particular, since the positive electrode materials of Examples 5 to 9 contain an organic solvent excellent in wettability with the positive electrode active material, both the initial discharge capacity and the positive electrode resistance are good.

In Comparative Example 1, since lithium tungstate is not mixed, the positive electrode resistance is significantly high, and it is difficult to meet the demand for higher output.
In Comparative Example 2, since the particle size of lithium tungstate Li ₂ WO ₄ as a tungsten additive material was 10 μm, which was out of the scope of the present invention, the positive electrode resistance was increased similarly to Comparative Example 1, and there was a demand for higher output. It is difficult to respond.
Further, in Comparative Example 3, only NMP that was not excellent in wettability with the positive electrode active material was used as the organic solvent, so that the positive electrode resistance could not be lowered as compared with the case where an organic solvent excellent in wettability was used.

In Example 8, an organic solvent having good wettability with the powder was added and mixed, so that the initial discharge capacity was high and the positive electrode resistance was low.
In Example 9, after mixing an organic solvent having good wettability with the powder and forming a positive electrode material, N-methyl-2-pyrrolidinone, a solvent that dissolves the binder together with the conductive material and the binder. It can be seen that good characteristics are obtained even when (NMP) is mixed.

  From the above results, it can be confirmed that the non-aqueous electrolyte secondary battery using the positive electrode material of the present invention has a high initial discharge capacity and a low positive electrode resistance, and has excellent characteristics.

The non-aqueous electrolyte secondary battery of the present invention is suitable for a power source of a small portable electronic device (such as a notebook personal computer or a mobile phone terminal) that always requires a high capacity, and an electric vehicle battery that requires a high output. Also suitable.
In addition, the nonaqueous electrolyte secondary battery of the present invention has excellent safety, and can be downsized and increased in output, and thus is suitable as a power source for an electric vehicle subject to restrictions on mounting space.
The present invention can be used not only as a power source for an electric vehicle driven purely by 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.

DESCRIPTION OF SYMBOLS 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)

Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) A non-aqueous electrolyte secondary characterized by mixing a composite oxide powder and a tungsten additive material of 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 battery. Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) Composite oxide powder, at least one organic solvent selected from ethanol, methanol, propanol, butanol and acetonitrile, tungsten oxide having a particle size of 0.01 to 0.09 μm, or 0.01 to 0.09 μm A method for producing a positive electrode material for a non-aqueous electrolyte secondary battery, comprising mixing a tungsten-added material of lithium tungstate.   The non-aqueous electrolyte secondary according to claim 1, further comprising a step of washing the lithium metal composite oxide powder with water before mixing the lithium metal composite oxide powder and the tungsten additive material. A method for producing a positive electrode material for a battery.   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 additive element M contained in the lithium metal composite oxide powder. The manufacturing method of the positive electrode material for nonaqueous electrolyte secondary batteries of any one of Claims 1-3 to do. The tungsten additive 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 . 5. The method for producing a positive electrode material for a non-aqueous electrolyte secondary battery according to any one of 4. Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) A non-aqueous electrolyte comprising a mixture of a composite oxide powder and a tungsten additive material of 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 Positive electrode material for secondary battery. Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) Composite oxide powder, at least one organic solvent selected from ethanol, methanol, propanol, butanol and acetonitrile, tungsten oxide having a particle size of 0.01 to 0.09 μm, or 0.01 to 0.09 μm A positive electrode material for a non-aqueous electrolyte secondary battery, comprising a mixture of the lithium tungstate and a tungsten additive material.
  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 additive element M contained in the lithium metal composite oxide powder. The positive electrode material for a non-aqueous electrolyte secondary battery according to claim 6 or 7. The tungsten additive material according to claim, characterized in that tungsten oxide, or _{Li 2 WO 4, Li 4 WO} 5, at least one lithium tungstate selected from Li ₆ W 2 _{O 9} of WO ₃ 6 The positive electrode material for nonaqueous electrolyte secondary batteries of any one of -8. 10. The positive electrode material for a non-aqueous electrolyte secondary battery according to claim 9, wherein the tungsten-added material is lithium tungstate containing Li ₄ WO ₅ when lithium tungstate is used. Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) A mixture of a composite oxide powder, N-methyl-2-pyrrolidinone, and a tungsten additive material of 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 non-aqueous electrolyte secondary battery.   It has a positive electrode containing the positive electrode material for nonaqueous electrolyte secondary batteries of any one of Claims 6-11, The nonaqueous electrolyte secondary battery characterized by the above-mentioned. Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) In a mixture of a composite oxide powder and a tungsten additive material of 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 mixture for a non-aqueous electrolyte secondary battery, comprising mixing a conductive material and a binder, and N-methyl-2-pyrrolidinone as a solvent for dissolving the binder. Formula _{Li z Ni 1-x-y} Co x M y O 2 ( however, 0.01 ≦ x ≦ 0.35,0 ≦ y ≦ 0.35,0.97 ≦ z ≦ 1.20, M is added Lithium metal consisting of primary particles and secondary particles formed by agglomeration of the primary particles, which is an element and is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) Complex oxide powder;
Tungsten additive material of at least one organic solvent selected from ethanol, methanol, propanol, butanol and acetonitrile 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 To the mixture with
A method for producing a positive electrode mixture for a non-aqueous electrolyte secondary battery, comprising mixing a conductive material and a binder, and N-methyl-2-pyrrolidinone as a solvent for dissolving the binder.   A non-aqueous electrolyte secondary battery comprising a positive electrode containing a positive electrode mixture for a non-aqueous electrolyte secondary battery according to the production method according to claim 13 or 14.

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