WO2021172560A1

WO2021172560A1 - Conductive carbon material dispersant for energy device, conductive carbon material dispersion for energy device, composition for energy device electrode formation and manufacturing method therefor, energy device electrode, and energy device

Info

Publication number: WO2021172560A1
Application number: PCT/JP2021/007505
Authority: WO
Inventors: 広喜葛岡; 拓也西村; 琢澤木; 健司鈴木
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2020-02-28
Filing date: 2021-02-26
Publication date: 2021-09-02
Also published as: WO2021171568A1; TW202137615A; JPWO2021172560A1

Abstract

This conductive carbon material dispersant for an energy device contains a resin comprising structural units derived from nitrile group-containing monomers.

Description

Conductive carbon material dispersant for energy devices, conductive carbon material dispersion for energy devices, compositions for forming energy device electrodes and their manufacturing methods, energy device electrodes, and energy devices

The present disclosure relates to a conductive carbon material dispersant for an energy device, a conductive carbon material dispersion for an energy device, a composition for forming an energy device electrode and a method for producing the same, an energy device electrode, and an energy device.

A lithium ion secondary battery, which is a non-aqueous electrolyte energy device having a high energy density, is widely used as a power source for mobile information terminals such as notebook personal computers, mobile phones, and PDAs (Personal Digital Assistants).

A carbon material having a multilayer structure capable of inserting and releasing lithium ions between layers (formation of a lithium interlayer compound) is mainly used as an active material for a negative electrode in a lithium ion secondary battery. Further, as the active material of the positive electrode, a lithium-containing metal composite oxide is mainly used. For the electrodes of the lithium ion secondary battery, these active materials, a binder resin, a carbon material such as carbon black, a solvent (N-methyl-2-pyrrolidone, water, etc.), etc. are kneaded to prepare a slurry, and then this is prepared. Is applied to one or both sides of a metal foil as a current collector with a transfer roll or the like, the solvent is removed by drying to form a mixture layer, and then compression molding is performed with a roll press machine or the like.

The carbon material is added for the purpose of imparting electron conductivity in the electrode. In the recent trend of increasing the capacity of lithium ion secondary batteries, the amount of carbon material added, which does not contribute to the increase in capacity, is being reduced. The particle size of carbon materials is becoming smaller in order to reduce the amount of carbon materials added.

Japanese Unexamined Patent Publication No. 2012-59466 proposes a kneading process for efficiently and stably and uniformly dispersing a positive electrode mixture containing a carbon material.
Further, International Publication No. 2012/014616 proposes a carbon slurry containing a polyvinylpyrrolidone-based polymer and a nonionic surfactant as a dispersant. Dispersants such as polyvinylpyrrolidone-based polymers and nonionic surfactants are effective in dispersing carbon materials.

In order to reduce the amount of carbon material added, it is effective to use a carbon material having a small average particle size. However, the kneading process described in JP2012-59466 may be less effective for carbon materials having a small average particle size.
Further, although the dispersant described in International Publication No. 2012/014616 is effective for dispersing carbon materials, side reactions such as oxidative decomposition are likely to occur in the battery, and the capacity of the battery is reduced, gas is generated, and the like. There is a concern that it will lead to problems.
Therefore, an effective dispersant for dispersing a carbon material having a small average particle size has been required.
The present disclosure has been made in view of the above-mentioned conventional circumstances, and an object of the present disclosure is to provide a conductive carbon material dispersant for an energy device having excellent dispersibility. Furthermore, it is an object of the present disclosure to provide a conductive carbon material dispersion for an energy device using this dispersant, a composition for forming an energy device electrode and a method for producing the same, an energy device electrode, and an energy device. ..

Specific means for achieving the above-mentioned problems are as follows.
<1> A conductive carbon material dispersant for energy devices containing a resin containing a structural unit derived from a nitrile group-containing monomer.
<2> The conductive carbon material dispersant for an energy device according to <1>, wherein the resin further contains a structural unit derived from a monomer represented by the following formula (I).

[In formula (I), R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom or a monovalent hydrocarbon group, and n represents an integer of 1 to 50. ]
<3> The conductive carbon material dispersant for energy devices according to <1> or <2>, wherein the structural unit derived from the nitrile group-containing monomer is contained in the main chain of the resin.
<4> The item according to any one of <1> to <3>, wherein the ratio of the structural unit derived from the nitrile group-containing monomer to the resin based on the mass is more than 80% by mass and 100% by mass or less. Conductive carbon material dispersant for energy devices.
<5> A conductive carbon material dispersion liquid for an energy device containing a conductive carbon material, a conductive carbon material dispersant for an energy device according to any one of <1> to <4>, and a solvent. ..
<6> The conductive carbon material dispersion liquid for an energy device according to <5>, wherein the average primary particle size of the conductive carbon material is 50 nm or less.
<7> The conductive carbon material dispersion liquid for an energy device according to <5> or <6>, wherein the conductive carbon material contains carbon black.
<8> The conductive carbon material dispersion liquid for an energy device according to any one of <5> to <7>, wherein the average particle size of the conductive carbon material is 0.3 μm to 3 μm.
<9> The conductive carbon material dispersion liquid for an energy device according to <5>, wherein the conductive carbon material contains carbon fibers.
<10> The conductive carbon material dispersion liquid for an energy device according to any one of <5> to <9>, wherein the solvent contains at least one of N-methyl-2-pyrrolidone and γ-butyrolactone.
<11> A binder resin, an active material, a conductive carbon material, a dispersant for dispersing the conductive carbon material, and a solvent are contained, and the dispersant is any of <1> to <4>. A composition for forming an energy device electrode, which comprises the conductive carbon material dispersant for an energy device according to item 1.
<12> A step of preparing an active material dispersion liquid by mixing the active material and the conductive carbon material dispersion liquid for an energy device according to any one of <5> to <10>, and the above-mentioned active material. A method for producing a composition for forming an energy device electrode, comprising a step of adding a binder resin to a dispersion liquid.
<13> The method for producing an energy device electrode forming composition according to <12>, which comprises a step of adding a conductive carbon material to the active material dispersion liquid.
<14> With the current collector
It is formed by using the energy device electrode forming composition provided on at least one surface of the current collector and produced by the method for producing the energy device electrode forming composition according to <12> or <13>. With the electrode mixture layer
Energy device electrode with.
<15> An energy device including the energy device electrode according to <14>.

According to the present disclosure, it is possible to provide a conductive carbon material dispersant for an energy device having excellent dispersibility. Further, according to the present disclosure, it is possible to provide a conductive carbon material dispersion for an energy device using this dispersant, a composition for forming an energy device electrode and a method for producing the same, an energy device electrode, and an energy device. ..

It is sectional drawing of the lithium ion secondary battery to which this disclosure is applied.

Hereinafter, the mode for implementing the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to the numerical values and their ranges, and does not limit this disclosure.

In the present disclosure, the term "process" includes not only a process independent of other processes but also the process if the purpose of the process is achieved even if the process cannot be clearly distinguished from the other process. ..
The numerical range indicated by using "-" in the present disclosure includes the numerical values before and after "-" as the minimum value and the maximum value, respectively.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. .. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
In the present disclosure, each component may contain a plurality of applicable substances. When a plurality of substances corresponding to each component are present in the composition, the content or content of each component is the total content or content of the plurality of substances present in the composition unless otherwise specified. Means quantity.
In the present disclosure, the particles corresponding to each component may include a plurality of types of particles. When a plurality of particles corresponding to each component are present in the composition, the particle size of each component means a value for a mixture of the plurality of particles present in the composition unless otherwise specified.
In the present disclosure, the term "layer" or "membrane" is used only in a part of the region in addition to the case where the layer or the membrane is formed in the entire region when the region in which the layer or the membrane is present is observed. The case where it is formed is also included.
In the present disclosure, the term "laminated" refers to stacking layers, and two or more layers may be bonded or the two or more layers may be removable.
In the present disclosure, "(meth) acrylic" means at least one of acrylic and methacryl, and "(meth) acrylate" means at least one of acrylate and methacrylate.
In the present disclosure, the average thickness of a layer or film is a value given as an arithmetic mean value obtained by measuring the thickness of five points of the target layer or film.
The thickness of the layer or film can be measured using a micrometer or the like. In the present disclosure, when the thickness of a layer or a film can be directly measured, it is measured using a micrometer. On the other hand, when measuring the thickness of one layer or the total thickness of a plurality of layers, the measurement may be performed by observing the cross section of the measurement target using an electron microscope.

<Conductive carbon material dispersant for energy devices>
The conductive carbon material dispersant for energy devices of the present disclosure (hereinafter, may be simply referred to as “dispersant”) is a resin containing a structural unit derived from a nitrile group-containing monomer (hereinafter, “specific nitrile resin”). May be referred to as).
As a result of diligent studies, the present inventors have found that the dispersant of the present disclosure has excellent dispersibility with respect to carbon materials such as carbon black, and have completed the present invention.

The components constituting the dispersant of the present disclosure will be described in detail below.

-Nitrile group-containing monomer-
The nitrile group-containing monomer, which is the source of the structural unit derived from the nitrile group-containing monomer contained in the specific nitrile resin, is not particularly limited. Examples thereof include acrylic nitrile group-containing monomers such as acrylonitrile and methacrylonitrile, cyanide nitrile group-containing monomers such as α-cyanoacrylate and dicyanovinylidene, and fumal nitrile group-containing monomers such as fumaronitrile. Be done.
Among these, acrylonitrile is preferable in terms of ease of polymerization, cost performance, further improvement in dispersibility of the conductive carbon material, and the like. The ratio of acrylonitrile to the nitrile group-containing monomer is preferably 5% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, and 70% by mass to 100% by mass. Is even more preferable. These nitrile group-containing monomers may be used alone or in combination of two or more.
When acrylonitrile and methacrylonitrile are used in combination as the nitrile group-containing monomer, the content of acrylonitrile is preferably, for example, 5% by mass to 95% by mass with respect to the total amount of the nitrile group-containing monomer. , 50% by mass to 95% by mass, more preferably.
The mass-based ratio of the structural unit derived from the nitrile group-containing monomer to the specific nitrile resin may be more than 80% by mass and 100% by mass or less, or 90% by mass to 100% by mass. , 92% by mass to 100% by mass.

The structural unit derived from the nitrile group-containing monomer is preferably contained in the main chain of the specific nitrile resin. In the present disclosure, the "main chain" of the specific nitrile resin means a site in which the monomers are linked by polymerization when the specific nitrile resin is synthesized when the specific nitrile resin is linear, for example, acrylonitrile is polymerized. In the case of a polymer, it means an alkylene moiety in which vinyl groups in acrylonitrile are linked by polymerization. When the specific nitrile resin is a graft polymer, the "main chain" of the specific nitrile resin means a portion of the copolymer that serves as a trunk.

-Monomer represented by the formula (I)-
The specific nitrile resin may contain a structural unit derived from a monomer represented by the following general formula (I), if necessary.

In formula (I), R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom or a monovalent hydrocarbon group, and n represents an integer of 1 to 50.

In formula (I), n is an integer of 1 to 50, preferably an integer of 2 to 30, more preferably an integer of 2 to 15, and an integer of 2 to 10. Is even more preferable. In another aspect, n is preferably an integer of 1 to 30, more preferably an integer of 1 to 15, and even more preferably an integer of 1 to 10.
In the formula (I), R ₂ is a hydrogen atom or a monovalent hydrocarbon group, preferably a monovalent hydrocarbon group, for example, and a monovalent hydrocarbon group having 1 to 50 carbon atoms. It is more preferable that it is a monovalent hydrocarbon group having 1 to 25 carbon atoms, and it is particularly preferable that it is a monovalent hydrocarbon group having 1 to 12 carbon atoms.
Examples of the hydrocarbon group include an alkyl group and a phenyl group. R ₂ is particularly, it is appropriate that the carbon number of alkyl group or a phenyl group having 1 to 12. The alkyl group may be linear, branched or cyclic.
Alkyl group and phenyl group represented by R _2, a part of hydrogen atoms may be substituted with a substituent. Examples of the substituent when R ₂ is an alkyl group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a substituent containing a nitrogen atom, a substituent containing a phosphorus atom, an aromatic ring and the like. .. When R ₂ is a phenyl group, the substituents include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, substituents containing nitrogen atom, substituents containing phosphorus atom, aromatic ring and carbon number. Examples thereof include 3 to 10 cycloalkyl groups.

As the monomer represented by the formula (I), a commercially available product or a synthetic product may be used. Specific examples of the monomer represented by the formula (I) that can be obtained as a commercially available product include 2-methoxyethyl acrylate and ethoxydiethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate EC-). A), methoxytriethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate MTG-A and manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name: NK ester AM-30G), methoxypoly (n = 9) ethylene glycol Acrylic (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate 130-A and Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AM-90G), methoxypoly (n = 13) ethylene glycol acrylate (Shin-Nakamura Chemical Co., Ltd.) Company, trade name: NK ester AM-130G), methoxypoly (n = 23) ethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name: NK ester AM-230G), octoxypoly (n = 18) ethylene glycol acrylate (Made by Shin-Nakamura Chemical Co., Ltd., Product name: NK ester A-OC-18E), Phenoxydiethylene glycol acrylate (Made by Kyoeisha Chemical Co., Ltd., Product name: Light acrylate P-200A and Shin-Nakamura Chemical Co., Ltd., Product name : NK ester AMP-20GY), Phenoxypoly (n = 6) ethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AMP-60G), nonylphenol EO adduct (n = 4) acrylate (Kyoeisha Chemical Co., Ltd.) Made by Kyoeisha Chemical Co., Ltd., trade name: Light Acrylate NP-4EA), nonylphenol EO adduct (n = 8) acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Acrylate NP-8EA), methoxydiethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) , Product name: Light ester MC and manufactured by Shin-Nakamura Chemical Industry Co., Ltd., Product name: NK ester M-20G), methoxytriethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., Product name: Light ester MTG), methoxypoly (n = 9) Ethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester 130MA and Shin Nakamura Chemical Co., Ltd., trade name: NK ester M-90G), methoxypoly (n = 23) ethylene glycol methacrylate (Shin Nakamura Chemical Co., Ltd.) Made by Kogyo Co., Ltd., trade name: NK Ester M-230G) and Met Examples thereof include xipoly (n = 30) ethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light ester 041MA).
Among these, from the viewpoint of reactivity when copolymerized with a nitrile group-containing monomer, methoxypoly (n = 9) ethylene glycol acrylate (R _{1 of the} general formula (I) is a hydrogen atom, and R ₂ is A compound having a methyl group and n of 9) is more preferable. As these monomers represented by the general formula (I), one type may be used alone, or two or more types may be used in combination.

-Monomer represented by formula (II)-
The specific nitrile resin may contain a structural unit derived from a monomer represented by the formula (II), if necessary. The monomer represented by the formula (II) used in the present disclosure is not particularly limited.

In formula (II), R ₃ represents a hydrogen atom or a methyl group, and R ₄ represents an alkyl group having 4 to 100 carbon atoms.

In formula (II), R ₄ is an alkyl group having 4 to 100 carbon atoms, preferably an alkyl group having 4 to 50 carbon atoms, and more preferably an alkyl group having 6 to 30 carbon atoms. , More preferably an alkyl group having 8 to 15 carbon atoms.
The _{alkyl group represented by R 4} may be linear, branched or cyclic.
Alkyl group represented by R _4, a part of hydrogen atoms may be substituted with a substituent. Examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a substituent containing a nitrogen atom, a substituent containing a phosphorus atom, and an aromatic ring. For example, the alkyl group represented by R _4, linear, other saturated alkyl group branched or cyclic fluoroalkyl group, chloroalkyl group, bromo group, halogenated alkyl group such as an alkyl iodide group And so on.

As the monomer represented by the formula (II), a commercially available product or a synthetic product may be used. Specific examples of the commercially available monomer represented by the formula (II) include n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and amyl (meth). ) Acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) ) Acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, etc. Examples thereof include (meth) acrylic acid esters containing 4 to 100 alkyl groups.
When R ₄ is a fluoroalkyl group, 1,1-bis (trifluoromethyl) -2,2,2-trifluoroethyl acrylate, 2,2,3,3,4,5,4-heptafluoro Butyl acrylate, 2,2,3,4,5-hexafluorobutyl acrylate, nonafluoroisobutyl acrylate, 2,2,3,3,4,5,5-octafluoropentyl acrylate, 2,2 , 3,3,4,4,5,5,5-nonafluoropentyl acrylate, 2,2,3,3,4,5,5,6,6,6-undecafluorohexyl acrylate, 2, 2,3,3,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl acrylate, 3,3,4,4,5,5,6,6 7,7,8,8,9,9,10,10,10-heptadecafluorodecylacrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8, Acrylate compounds such as 8,9,9,10,10,10-nonadecafluorodecylacrylate, nonafluoro-t-butyl methacrylate, 2,2,3,3,4,4-heptafluorobutyl methacrylate, 2, 2,3,3,4,5,5-octafluoropentyl methacrylate, 2,2,3,3,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate, heptadeca Fluorooctyl methacrylate, 2,2,3,3,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl methacrylate, 2,2,3,3,4 Examples thereof include methacrylate compounds such as 4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononyl methacrylate.
As these monomers represented by the general formula (II), one type may be used alone, or two or more types may be used in combination.

-Carboxy group-containing monomer-
The specific nitrile resin may contain a structural unit derived from a carboxy group-containing monomer, if necessary.
Specific examples of the carboxy group-containing monomer are not particularly limited, and are acrylic carboxy group-containing monomer such as acrylic acid and methacrylic acid, croton-based carboxy group-containing monomer such as crotonic acid, maleic acid and its anhydride. Examples thereof include a maleine-based carboxy group-containing monomer such as a product, an itaconic acid-based carboxy group-containing monomer such as itaconic acid and its anhydride, and a citraconic carboxy group-containing monomer such as citraconic acid and its anhydride.

-Other monomers-
The specific nitrile resin is derived from a monomer-derived structural unit represented by the general formula (I), a monomer-derived structural unit represented by the general formula (II), and a carboxy group-containing monomer, if necessary. It may contain structural units derived from other monomers other than the structural units of.
The other monomer is not particularly limited, and is a (meth) acrylic containing an alkyl group having 1 to 3 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. Acid esters, vinyl chloride, vinyl bromide, vinyl halides such as vinylidene chloride, imide maleate, phenylmaleimide, (meth) acrylamide, styrene, α-methylstyrene, vinyl acetate, sodium (meth) allylsulfonate, Examples thereof include sodium (meth) allyloxybenzene sulfonic acid, sodium styrene sulfonate, 2-acrylamide-2-methylpropanesulfonic acid and salts thereof. These other monomers may be used alone or in combination of two or more.

-Ratio of structural units derived from each monomer-
The ratio of the structural units derived from each of the above monomers contained in the specific nitrile resin is not particularly limited.
The ratio of the structural units derived from the nitrile group-containing monomer to the total of the structural units derived from each of the above-mentioned monomers contained in the specific nitrile resin may be 50 mol% to 100 mol%, and may be 80 mol% to 80 mol%. It may be 100 mol%, 90 mol% to 100 mol%, 95 mol% to 100 mol%.
When the ratio of the structural units derived from the nitrile group-containing monomer to the total structural units derived from each monomer is 90 mol% to 100 mol%, n in the monomer represented by the formula (I) is It may indicate an integer of 2 to 50.
The ratio of the structural unit derived from the carboxy group-containing monomer and containing the carboxy group to 1 mol of the structural unit derived from the nitrile group-containing monomer may be 0.005 mol or less, and 0.001 mol or less. There may be.
The ratio of the structural unit derived from the monomer represented by the formula (I) to 1 mol of the structural unit derived from the nitrile group-containing monomer may be, for example, 0.001 mol to 0.2 mol, and is 0. It may be 0.003 mol to 0.05 mol, or 0.005 mol to 0.035 mol. If the ratio of the structural unit derived from the monomer represented by the formula (I) to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol, the dispersant of the present disclosure can be used. The ionic conductivity of the containing electrode mixture layer tends to be improved.

When the specific nitrile resin contains a structural unit derived from a monomer represented by the formula (II), it is derived from the monomer represented by the formula (II) with respect to 1 mol of the structural unit derived from the nitrile group-containing monomer. The ratio of structural units may be, for example, 0.001 mol to 0.2 mol, 0.003 mol to 0.05 mol, and 0.005 mol to 0.02 mol. May be good.

When the specific nitrile resin contains a structural unit derived from a monomer represented by the formula (I) and a structural unit derived from a monomer represented by the formula (II), a structural unit derived from a nitrile group-containing monomer. The total ratio of the monomer-derived structural unit represented by the formula (I) and the monomer-derived structural unit represented by the formula (II) to 1 mol is, for example, 0.001 mol to 0.2. It may be a molar amount, 0.003 mol to 0.05 mol, or 0.005 mol to 0.035 mol.

When the specific nitrile resin contains structural units derived from other monomers, the ratio of structural units derived from other monomers to 1 mol of structural units derived from nitrile group-containing monomers is, for example, 0.005 mol. It may be up to 0.1 mol, 0.01 mol to 0.06 mol, or 0.03 mol to 0.05 mol.

-Manufacturing method of specific nitrile resin-
The method for producing the specific nitrile resin is not particularly limited. Polymerization methods such as underwater precipitation polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization can be applied. Precipitation polymerization in water is preferable in terms of ease of resin synthesis, ease of post-treatment such as recovery and purification, and the like.
Hereinafter, the precipitation polymerization in water will be described in detail.

-Polymerization initiator-
As the polymerization initiator when performing precipitation polymerization in water, it is preferable to use a water-soluble polymerization initiator in terms of polymerization initiation efficiency and the like.
Examples of the water-soluble polymerization initiator include persulfates such as ammonium persulfate, potassium persulfite and sodium bisulfite, water-soluble peroxides such as hydrogen peroxide, and 2,2'-azobis (2-methylpropion amidine hydrochloride). A combination of a water-soluble azo compound such as, an oxidizing agent such as persulfate, a reducing agent such as sodium bisulfite, ammonium hydrogen peroxide, sodium thiosulfite, and hydrosulfite, and a polymerization accelerator such as sulfuric acid, iron sulfate, and copper sulfate. Redox type (redox type) and the like.
Among these, persulfates, water-soluble azo compounds and the like are preferable in terms of ease of resin synthesis and the like. Among the persulfates, ammonium persulfate is particularly preferable.
When acrylonitrile is selected as the nitrile group-containing monomer and methoxypoly (n = 9) ethylene glycol acrylate is selected as the monomer represented by the formula (I) and precipitation polymerization is carried out in water, the monomer is used. Since both are water-soluble in the above state, the water-soluble polymerization initiator acts effectively and the polymerization starts smoothly. Then, as the polymerization progresses, the polymer is precipitated, so that the reaction system is suspended, and finally, a specific nitrile resin having a small amount of unreacted substances can be obtained in high yield.
The polymerization initiator is preferably used in the range of, for example, 0.001 mol% to 5 mol%, and 0.003 mol% to 2 with respect to the total amount of the monomers used in the synthesis of the specific nitrile resin. More preferably, it is used in the range of mol%.

-Chain transfer agent-
When performing precipitation polymerization in water, a chain transfer agent can be used for the purpose of adjusting the molecular weight and the like. Examples of the chain transfer agent include mercaptan compounds such as thioglycol, carbon tetrachloride, α-methylstyrene dimer and the like. Among these, α-methylstyrene dimer and the like are preferable in terms of having less odor and the like.

-solvent-
When performing precipitation polymerization in water, a solvent other than water can be added as needed, such as adjusting the particle size of the precipitated resin.
Solvents other than water include amides such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, N-dimethylethyleneurea, N, N-dimethylpropyleneurea, and tetra. Ureas such as methyl urea, lactones such as γ-butyrolactone and γ-caprolactone, carbonates such as propylene carbonate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate , Butyl cellosolve acetate, butyl carbitol acetate, ethyl cellosolve acetate, ethyl carbitol acetate and other esters, jig lime, triglime, tetraglyme and other glymes, toluene, xylene, cyclohexane and other hydrocarbons, dimethyl sulfoxide and other sulfoxides. , Sulfones such as sulfolane, alcohols such as methanol, isopropanol and n-butanol. These solvents may be used alone or in combination of two or more.

-Polymerization conditions-
In the precipitation polymerization in water, for example, the monomer is introduced into a solvent, and the polymerization temperature is preferably 0 ° C. to 100 ° C., more preferably 30 ° C. to 90 ° C., preferably 1 hour to 50 hours, more preferably 2 This is done by holding for hours to 12 hours.
When the polymerization temperature is 0 ° C. or higher, the polymerization reaction tends to be promoted. Further, when the polymerization temperature is 100 ° C. or lower, even when water is used as a solvent, the water tends to evaporate and the polymerization tends to be difficult to occur.
In particular, since the heat of polymerization of the nitrile group-containing monomer tends to be large, it is preferable to proceed with the polymerization while dropping the nitrile group-containing monomer into the solvent.

The weight average molecular weight of the specific nitrile resin is preferably 10,000 to 1,000,000, more preferably 100,000 to 800,000, and even more preferably 250,000 to 700,000.
In the present disclosure, the weight average molecular weight refers to a value measured by the following method.
The object to be measured is dissolved in N-methyl-2-pyrrolidone, and a filter made of PTFE (polytetrafluoroethylene) [manufactured by Kurashiki Spinning Co., Ltd., for HPLC (high performance liquid chromatography) pretreatment, chromatographic disk, model number: 13N, pore size: 0.45 μm] to remove insoluble matter. GPC [Pump: L6200 Pump (manufactured by Hitachi, Ltd.), Detector: Differential refractometer detector L3300 RI Matter (manufactured by Hitachi, Ltd.), Columns: TSKgel-G5000HXL and TSKgel-G2000HXL (2 in total) (both Tosoh) (Manufactured by Co., Ltd.) are connected in series, column temperature: 30 ° C., eluent: N-methyl-2-pyrrolidone, flow velocity: 1.0 mL / min, standard substance: polystyrene], and the weight average molecular weight is measured.

The acid value of the specific nitrile resin is preferably 0 mgKOH / g to 70 mgKOH / g, more preferably 0 mgKOH / g to 20 mgKOH / g, and even more preferably 0 mgKOH / g to 5 mgKOH / g.
In the present disclosure, the acid value refers to a value measured by the following method.
First, 1 g of the measurement target is precisely weighed, and then 30 g of acetone is added to the measurement target to dissolve the measurement target. Next, an appropriate amount of phenolphthalein, which is an indicator, is added to the solution to be measured, and titration is performed using a 0.1 N KOH aqueous solution. Then, the acid value is calculated from the titration result by the following formula (A) (in the formula, Vf indicates the titration amount (mL) of phenolphthalein, Wp indicates the mass (g) of the solution to be measured, and I is The percentage (% by mass) of the non-volatile content of the solution to be measured).
Acid value (mgKOH / g) = 10 x Vf x 56.1 / (Wp x I) (A)
The non-volatile content of the solution to be measured is calculated from the weight of the residue after measuring about 1 mL of the solution to be measured in an aluminum pan, drying it on a hot plate heated to 160 ° C. for 15 minutes.

In the dispersant of the present disclosure, an unreacted monomer used when synthesizing the specific nitrile resin may remain as a component other than the specific nitrile resin. The content of the unreacted monomer contained in the dispersant of the present disclosure is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less.

<Conductive carbon material dispersion for energy devices>
The conductive carbon material dispersion liquid for energy devices of the present disclosure (hereinafter, may be simply referred to as “dispersion liquid”) contains a conductive carbon material, a dispersant of the present disclosure, and a solvent.

The components constituting the dispersion liquid of the present disclosure will be described in detail below.

-Conductive carbon material-
The conductive carbon material contained in the dispersion liquid of the present disclosure is not particularly limited as long as it exhibits conductivity.
As the conductive carbon material, carbon black, graphite, carbon nanotubes, carbon fiber (carbon fiber) and the like can be used.
Examples of carbon black include acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black and the like. Examples of graphite include natural graphite and artificial graphite.
Examples of carbon nanotubes include single-walled carbon nanotubes, two-walled carbon nanotubes, and multi-walled carbon nanotubes.
Examples of the carbon fiber include pitch-based carbon fiber, PAN-based carbon fiber, vapor phase carbon fiber (VGCF (registered trademark)) and the like.
As the conductive carbon material, carbon black is preferable.
One type of conductive carbon material may be used alone, or two or more types may be used in combination.

When a particulate material such as carbon black or graphite is used as the conductive carbon material, the average primary particle size of the conductive carbon material is preferably 50 nm or less, more preferably 40 nm or less, and more preferably 30 nm or less. It is more preferable to have. The average primary particle size of the conductive carbon material may be 10 nm or more.
In the present disclosure, the average primary particle size means an average value of the diameters of several thousand primary particles.

When a particulate material such as carbon black or graphite is used as the conductive carbon material, the average particle size of the conductive carbon material is preferably 0.3 μm to 3 μm, more preferably 0.3 μm to 2 μm. It is more preferably 0.5 μm to 1.5 μm, and particularly preferably 0.8 μm to 1.0 μm.
The average particle size of the conductive carbon material is the particle size distribution obtained by measuring the particle size distribution of the conductive carbon material dispersion for energy devices based on the dynamic light scattering method (photon correlation method). It refers to the particle size where the number ratio is 50% when the number ratio is integrated from the one with the smallest diameter. Examples of the measuring device based on the dynamic light scattering method (photon correlation method) include Zeta-potential & Particularsize Analyzer and ELSZ (Otsuka Electronics Co., Ltd.).
When a fibrous material such as carbon nanotubes or carbon fibers is used as the conductive carbon material, the average length of the conductive carbon material is preferably 1 μm to 50 μm, more preferably 2 μm to 30 μm, and 3 μm. It is more preferably about 10 μm.
When a fibrous material such as carbon nanotubes or carbon fibers is used as the conductive carbon material, the average diameter of the conductive carbon material is preferably 1 nm to 500 nm, more preferably 5 nm to 400 nm, and 10 nm to 10 nm. It is more preferably 300 nm.
For the average length of the conductive carbon material, select any 30 conductive carbon materials, measure the length of each, and set the numerical value from the maximum side to the 5th and the numerical value from the minimum side to the 5th. Can be omitted, and the average value of the 20 intermediate values can be used as the average length. Since the average length of carbon nanotubes, carbon fibers, etc. is as short as several tens of μm or less, the length of the conductive carbon material can be approximated to be approximately linear. Therefore, the length of the conductive carbon material can be the length of the straight line when both ends thereof are connected by a straight line.
The average diameter of the conductive carbon material can be analyzed from electron micrographs (SEM, TEM, etc.). For example, select any 30 conductive carbon materials, measure the diameter of each, omit the 5th numerical value from the maximum side and the 5th numerical value from the minimum side, and 20 numerical values in the middle. The average value of may be the average diameter. The diameter of the conductive carbon material means the maximum length in the direction orthogonal to the length direction of the conductive carbon material.

The content of the conductive carbon material contained in the dispersion liquid of the present disclosure is, for example, preferably 1% by mass to 50% by mass, more preferably 5% by mass to 25% by mass, and 5% by mass. It is more preferably to 15% by mass.

-Dispersant-
The dispersion liquid of the present disclosure contains the dispersant of the present disclosure. The content of the dispersant of the present disclosure contained in the dispersion liquid of the present disclosure is, for example, preferably 0.1% by mass to 20% by mass, and 0.5% by mass to 15% by mass in some embodiments. It is more preferably 1% by mass to 10% by mass. In another aspect, it is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 8% by mass, and 0.3% by mass to 6% by mass. Is even more preferable.

-solvent-
The solvent contained in the dispersion liquid of the present disclosure is not particularly limited as long as it can disperse the conductive carbon material.
As the solvent, an amide-based solvent, a urea-based solvent, a lactone-based solvent, or a mixed solvent containing them is preferable from the viewpoint of solubility of the dispersant, and N-methyl-2-pyrrolidone, γ-butyrolactone, or a mixed solvent containing them is contained. A mixed solvent is more preferable. These solvents may be used alone or in combination of two or more.
Among these, the solvent preferably contains at least one of N-methyl-2-pyrrolidone and γ-butyrolactone.

-Viscosity of dispersion-
The viscosity of the dispersion liquid of the present disclosure at 25 ° C. is preferably 500 mPa · s to 50,000 mPa · s, more preferably 1000 mPa · s to 20000 mPa · s, and 2000 mPa · s to 10000 mPa · s. Is even more preferable.
In the present disclosure, the viscosity is measured using a rotary shear viscometer at 25 ° C. and a shear rate of 1.0 s- ^1.

-Preparation of dispersion-
The dispersion liquid of the present disclosure can be prepared by mixing a conductive carbon material, the dispersant of the present disclosure, other components such as a leveling agent used as necessary, and a solvent, and stirring the mixture.
Examples of the disperser used for preparing the dispersion liquid include a homomixer, a high-pressure homomixer, a disperser, a high-pressure homogenizer, a static mixer, a membrane emulsifier, a fill mix (manufactured by Primix Corporation), and an ultrasonic disperser. Of these, fill mix is preferred.
It is more preferable that various components used for preparing the dispersion liquid are pre-stirred with a disperser such as a homomixer and then stirred with a fill mix. The distributed processing can be completed in a short time by using the fill mix. The conditions for stirring with the fill mix are not particularly limited and can be carried out by a conventional method. For example, the conductive carbon material can be dispersed by stirring at a peripheral speed of 30 m / s for 30 seconds. The stirring time when stirring with the fill mix may be in the range of 30 seconds to 10 minutes.

<Composition for forming energy device electrodes and method for producing the same>
The energy device electrode forming composition of the present disclosure (hereinafter, may be referred to as an electrode forming composition) is a dispersion in which a binder resin, an active material, a conductive carbon material, and the conductive carbon material are dispersed. It contains an agent and a solvent, and the dispersant contains the dispersant of the present disclosure.

The components constituting the electrode-forming composition of the present disclosure will be described in detail below.

-Binder resin-
The electrode-forming composition of the present disclosure contains a binder resin. The type of the binder resin is not particularly limited, and examples thereof include polyvinyl acetate, polymethylmethacrylate, nitrocellulose, fluororesin, and resins containing structural units derived from nitrile group-containing monomers.
Among these, at least one of a fluororesin and a resin containing a structural unit derived from a nitrile group-containing monomer is preferable.

The fluororesin is not particularly limited as long as it contains a structural unit in which a part or all of hydrogen atoms in the polyethylene skeleton is replaced with a fluorine atom in the main chain.
Examples of the fluororesin include homopolymers such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylfluoride (PVF), and polychlorotrifluoroethylene (PCTFE), and tetrafluoroethylene-perfluoropropylene copolymers. (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer and other copolymers, and carboxy these. Examples thereof include a modified product modified with a group or the like. Among these, PVDF is preferable from the viewpoints of solubility in a solvent, swelling property in an electrolytic solution, flexibility of a resin, and the like. Further, these fluororesins may be used alone or in combination of two or more.

The resin containing a structural unit derived from a nitrile group-containing monomer may be the above-mentioned specific nitrile resin. As the resin containing a structural unit derived from a nitrile group-containing monomer, one type may be used alone, or two or more types may be used in combination.

The content of the binder resin in the solid content of the electrode-forming composition of the present disclosure is preferably 0.1% by mass to 10% by mass, and more preferably 0.5% by mass to 5% by mass. , 0.5% by mass to 3% by mass, more preferably.
In the present disclosure, the “solid content” refers to a component obtained by removing a solvent from the components constituting the electrode-forming composition.

-Active material-
The electrode-forming composition of the present disclosure may contain an active material. The active material used in the present disclosure is not particularly limited as long as it can reversibly insert and release lithium ions by charging and discharging a lithium ion secondary battery which is an energy device. The positive electrode has a function of releasing lithium ions at the time of charging and receiving lithium ions at the time of discharging, while the negative electrode has a function opposite to that of the positive electrode of receiving lithium ions at the time of charging and releasing lithium ions at the time of discharging. Have. Therefore, as the active material used in the positive electrode and the negative electrode, different materials are usually used according to the functions of each.

As the active material (negative electrode active material) used for the negative electrode of the lithium ion secondary battery, a material that can occlude and release lithium ions and is commonly used in the field of the lithium ion secondary battery can be used. Examples of the negative electrode active material include metallic lithium, lithium alloys, intermetallic compounds, carbon materials, metal complexes, organic polymer compounds and the like. One type of negative electrode active material may be used alone, or two or more types may be used in combination. Among these, a carbon material is preferable. Examples of the carbon material include natural graphite (scaly graphite and the like), graphite such as artificial graphite, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black and other carbon black, and carbon fiber. The average particle size of the carbon material is preferably 0.1 μm to 60 μm, more preferably 0.5 μm to 30 μm. The BET specific surface area of the carbon material ^{is preferably 1 m 2} / g to 10 m ² / g.
In the present disclosure, the average particle size of particles other than the conductive carbon material refers to a laser diffraction type particle size distribution measuring device (for example, SALD-3000J manufactured by Shimadzu Corporation) in which a sample is dispersed in purified water containing a surfactant. ), The value when the integration from the small diameter side is 50% (median diameter (D50)) in the volume-based particle size distribution.

Among the carbon materials, the distance between the carbon hexagonal planes (d ₀₀₂ ) in the X-ray wide-angle diffraction method is 3.35 Å to 3.40 Å from the viewpoint of further improving the battery characteristics, and the crystallites (Lc) in the c-axis direction. Graphite having a value of 100 Å or more is preferable.
_{Amorphous carbon having a carbon hexagonal plane spacing (d 002} ) of 3.50 Å to 3.95 Å in the X-ray wide-angle diffraction method, among other carbon materials, from the viewpoint of further improving cycle characteristics and safety. Is preferable.

The BET specific surface area can be measured from the nitrogen adsorption capacity according to, for example, JIS Z 8830: 2013. As the evaluation device, for example, QUANTACHROME Co., Ltd .: AUTOSORB-1 (trade name) can be used. Since it is considered that the water adsorbed on the sample surface and the structure affects the gas adsorption capacity, it is preferable to first perform a pretreatment for removing water by heating when measuring the BET specific surface area.
In the pretreatment, the measurement cell containing 0.05 g of the measurement sample is depressurized to 10 Pa or less with a vacuum pump, heated at 110 ° C., held for 3 hours or more, and then kept at room temperature (maintained in the depressurized state). Naturally cool to 25 ° C.). After this pretreatment, the evaluation temperature is set to 77K, and the evaluation pressure range is measured as a relative pressure (equilibrium pressure with respect to saturated vapor pressure) of less than 1.

On the other hand, as the active material (positive electrode active material) used for the positive electrode of the lithium ion secondary battery, those commonly used in this field can be used, for example, a lithium-containing metal composite oxide, an olivine-type lithium salt, a chalcogen compound, and the like. Examples thereof include manganese dioxide. The lithium-containing metal composite oxide is a metal oxide containing lithium and a transition metal, or a metal oxide in which a part of the transition metal in the metal oxide is replaced by a dissimilar element. Here, examples of the dissimilar elements include Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, V, B and the like, and Mn, Al, etc. Co, Ni, Mg and the like are preferable. One type of dissimilar element may be used alone, or two or more types may be used in combination.

Examples of the lithium-containing metal composite oxide include Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _y Ni _1-y O ₂ , and Li _x Co _y M ¹ _1-y O _z (Li). _{In x} Co _y M ¹ _1-y _Oz , M ¹ is at least one selected from the group consisting of Na, Mg, Sc, Y, Mn, Fe, Cu, Zn, Al, Cr, Pb, Sb, V and B. (Indicates the element of the species.), Li _x Ni _1-y M ² _y _Oz (in Li _x Ni _1-y M ² _y _Oz , M ² is Na, Mg, Sc, Y, Mn, Fe, Co, Indicates at least one element selected from the group consisting of Cu, Zn, Al, Cr, Pb, Sb, V and B), Li _x Mn ₂ O ₄ , Li _x Mn _2-y M ³ _y O ₄ ( In Li _x Mn _2-y M ³ _y O ₄ , M ³ is selected from the group consisting of Na, Mg, Sc, Y, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, V and B. It indicates at least one kind of element.) And the like. Here, x is in the range of 0 <x ≦ 1.2, y is in the range of 0 to 0.9, and z is in the range of 2.0 to 2.3. Further, the x value indicating the molar ratio of lithium increases or decreases depending on charging and discharging.
Moreover, as an olivine type lithium salt, for example, LiFePO _{4 and the} like can be mentioned. Examples of the chalcogen compound include titanium disulfide and molybdenum disulfide. Other positive electrode active materials include Li ₂ MPO ₄ F (in Li ₂ MPO ₄ F, M is Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb. , Sb, V and at least one element selected from the group consisting of B). One type of positive electrode active material may be used alone, or two or more types may be used in combination.

The average particle size of the positive electrode active material is preferably 0.1 μm to 60 μm, and more preferably 0.5 μm to 30 μm. The BET specific surface area of the positive electrode active material ^{is preferably 1 m 2} / g to 10 m ² / g.

-Conductive carbon material-
The electrode-forming composition of the present disclosure contains a conductive carbon material. Specific examples of the conductive carbon material contained in the electrode forming composition of the present disclosure are as described above.
The content of the conductive carbon material in the solid content of the electrode forming composition of the present disclosure is preferably 0.1% by mass to 10% by mass, and preferably 0.5% by mass to 5% by mass. More preferably, it is 1% by mass to 3% by mass.

-Dispersant-
The electrode-forming composition of the present disclosure contains a dispersant. The dispersant contained in the electrode-forming composition of the present disclosure includes the dispersant of the present disclosure. The electrode-forming composition of the present disclosure may contain other dispersants other than the dispersants of the present disclosure, if necessary.
Examples of other dispersants include polyvinylpyrrolidone, polyvinyl alcohol and the like.
The content of the dispersant in the solid content of the electrode forming composition of the present disclosure is preferably 0.1% by mass to 10% by mass, and more preferably 0.2% by mass to 5% by mass. , 0.3% by mass to 3% by mass, more preferably.
The content of the dispersant of the present disclosure in the dispersant contained in the composition for forming electrodes of the present disclosure is preferably 70% by mass or more, more preferably 80% by mass or more, and 90% by mass or more. It is more preferably mass% or more, and particularly preferably 100 mass%.

-solvent-
The electrode-forming composition of the present disclosure contains a solvent. Examples of the solvent include water, an amide solvent, a urea solvent, a lactone solvent and the like, or a mixed solvent containing them. In terms of solubility of the binder resin and the like, an amide solvent, a urea solvent, a lactone solvent and the like, etc. Alternatively, a mixed solvent containing them is preferable, and N-methyl-2-pyrrolidone, γ-butyrolactone or a mixed solvent containing them is more preferable. These solvents may be used alone or in combination of two or more.

The content of the solvent is not particularly limited as long as it is equal to or more than the minimum amount necessary for the binder resin to be kept in a dissolved state at room temperature (for example, 25 ° C.). In the slurry preparation step in the electrode production of the energy device, the viscosity is usually adjusted while adding a solvent, so it is preferable to use an arbitrary amount that is not excessively diluted.

-Other additives-
The electrode-forming composition of the present disclosure includes, as necessary, other materials such as a cross-linking component for complementing the swelling resistance to the electrolytic solution, and a rubber component for complementing the flexibility and flexibility of the electrode. It is also possible to add various additives such as a settling inhibitor, a defoaming agent, a leveling agent and the like for improving the electrode coatability of the slurry.

-Physical characteristics of the electrode forming composition-
The electrode-forming composition of the present disclosure preferably has a viscosity at 25 ° C. of 500 mPa · s to 50,000 mPa · s, more preferably 1000 mPa · s to 20000 mPa · s, and 2000 mPa · s to 10000 mPa · s. Is more preferable.

-Manufacturing method of electrode forming composition-
The method for producing the electrode-forming composition of the present disclosure is not particularly limited.
As an example of the method for producing the electrode-forming composition of the present disclosure, a step of preparing an active material dispersion liquid by mixing the active material and the dispersion liquid of the present disclosure, and adding a binder resin to the active material dispersion liquid. It may have a step of adding.
In the step of preparing the active material dispersion liquid, the active material dispersion liquid is prepared by mixing the active material, the dispersion liquid of the present disclosure, and other components used as necessary, and stirring the mixture.
Examples of the apparatus used for mixing and stirring include a planetary mixer, a homomixer, a high-pressure homomixer, a disperser, a high-pressure homogenizer, a static mixer, a membrane emulsifier, and an ultrasonic disperser.

In the step of adding the binder resin to the active material dispersion liquid, the binder resin added to the active material dispersion liquid is mixed by stirring to obtain the electrode forming composition of the present disclosure. The stirring method is not particularly limited, and examples thereof include the stirring method using the above-mentioned device mentioned in the step of preparing the active material dispersion liquid.

In the step of adding the binder resin to the active material dispersion liquid, a powdery conductive carbon material may be further added in order to adjust the content of the conductive carbon material.
Further, the method for producing the electrode-forming composition of the present disclosure may include a step of adding a conductive carbon material to the active material dispersion liquid obtained in the step of preparing the active material dispersion liquid.

When the electrode-forming composition of the present disclosure contains other components other than the active material, the binder resin, and the conductive carbon material, the other components may be added in the step of preparing the active material dispersion liquid. It may be added in the step of adding the binder resin to the active material dispersion liquid, or may be added in both steps.

<Energy device electrode>
The energy device electrode of the present disclosure is provided on the surface of at least one of the current collector and the current collector, and is produced by the method for producing the energy device electrode forming composition of the present disclosure. It has an electrode mixture layer formed by using an object.
The energy device electrodes of the present disclosure can be used as electrodes for lithium ion secondary batteries, electric double layer capacitors, solar cells, fuel cells and the like.
The case where the energy device electrode of the present disclosure is applied to the electrode of the lithium ion secondary battery will be described in detail below, but the energy device electrode of the present disclosure is not limited to the following contents.

-Current collector-
The current collector used in the present disclosure is not particularly limited, and a current collector commonly used in the field of a lithium ion secondary battery can be used.
Examples of the current collector (positive electrode current collector) used for the positive electrode of the lithium ion secondary battery include sheets and foils containing stainless steel, aluminum, titanium and the like.
Among these, a sheet or foil containing aluminum is preferable. The thickness of the sheet and the foil is not particularly limited, and from the viewpoint of ensuring the strength and workability required for the current collector, for example, it is preferably 1 μm to 500 μm, more preferably 2 μm to 80 μm, and 5 μm. It is more preferably ~ 50 μm.
Examples of the current collector (negative electrode current collector) used for the negative electrode of the lithium ion secondary battery include sheets and foils containing stainless steel, nickel, copper and the like.
Among these, a sheet or foil containing copper is preferable. The thickness of the sheet and the foil is not particularly limited, and from the viewpoint of ensuring the strength and workability required for the current collector, for example, it is preferably 1 μm to 500 μm, more preferably 2 μm to 100 μm, and 5 μm. It is more preferably ~ 50 μm.

-Electrode mixture layer-
The electrode mixture layer used in the lithium ion secondary battery can be formed by using an energy device electrode forming composition containing an active material, a solvent and the like.
A positive electrode mixture layer is formed by using a composition for forming an energy device electrode containing a positive electrode active material. On the other hand, a negative electrode mixture layer is formed by using a composition for forming an energy device electrode containing a negative electrode active material.

For the electrode mixture layer, a slurry of the energy device electrode forming composition produced by the method for producing the electrode forming composition of the present disclosure is applied onto at least one surface of the current collector, and then the solvent is dried. It can be removed and rolled if necessary.
The slurry can be applied using, for example, a comma coater or the like. It is appropriate that the coating is performed so that the ratio of the positive electrode capacity to the negative electrode capacity (negative electrode capacity / positive electrode capacity) is 1 or more in the opposing electrodes.
The amount of the slurry applied is, for example, preferably 5 g / m ² to 500 g / m ² and more preferably 50 g / m ² to 300 g / m ² in terms of the dry mass of the electrode mixture layer per side. ..
The solvent is removed, for example, by drying at 50 ° C. to 150 ° C., preferably 80 ° C. to 120 ° C. for 1 minute to 20 minutes, preferably 3 minutes to 10 minutes.
The rolling is carried out using, for example, a roll press machine, and when the density of the mixture layer is the mixture layer of the negative electrode, for example, 1 g / cm ³ to 2 g / cm ³ , preferably 1.2 g / cm ³ to In the case of the positive mixture layer so as to be 1.8 g / cm ³ , for example, it is pressed to be ^{2 g / cm 3} to 5 g / cm ³ , preferably 2 g / cm ³ to 4 g / cm ^3. ..
Further, in order to remove the residual solvent and adsorbed water in the electrode, for example, vacuum drying may be performed at 100 ° C. to 150 ° C. for 1 hour to 20 hours.

<Energy device>
The energy device of the present disclosure comprises the energy device electrode of the present disclosure. Examples of the energy device of the present disclosure include a lithium ion secondary battery, an electric double layer capacitor, a solar cell, a fuel cell and the like.
The case where the energy device is a lithium ion secondary battery will be described in detail below, but the energy device of the present disclosure is not limited to the following contents.

The lithium ion secondary battery includes, for example, a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolytic solution.
The energy device electrodes of the present disclosure are used as at least one of a positive electrode and a negative electrode. When an electrode other than the energy device electrode of the present disclosure is used as one of the positive electrode and the negative electrode, examples of the other electrode include those commonly used in the field of energy devices.

-Separator-
The separator is not particularly limited as long as it electronically insulates between the positive electrode and the negative electrode, has ion permeability, and has resistance to oxidizing property on the positive electrode side and reducing property on the negative electrode side. As the material (material) of the separator satisfying such characteristics, a resin, an inorganic substance, or the like is used.

As the resin, an olefin polymer, a fluoropolymer, a cellulosic polymer, a polyimide, a nylon, or the like is used. Specifically, it is preferable to select from materials that are stable to the electrolytic solution and have excellent liquid retention properties, and it is preferable to use a porous sheet made of polyolefin such as polyethylene or polypropylene, a non-woven fabric, or the like.

As the inorganic substance, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, barium sulfate, sulfates such as calcium sulfate, and glass are used. For example, a fiber-shaped or particle-shaped inorganic substance adhered to a thin-film-shaped base material such as a non-woven fabric, a woven fabric, or a microporous film can be used as a separator.
As the thin film-shaped base material, those having a pore diameter of 0.01 μm to 1 μm and a thickness of 5 μm to 50 μm are preferably used. Further, for example, a fiber-shaped or particle-shaped inorganic substance formed into a composite porous layer by using a binder such as a resin can be used as a separator. Further, this composite porous layer may be formed on the surface of the positive electrode or the negative electrode to serve as a separator. Alternatively, this composite porous layer may be formed on the surface of another separator to form a multilayer separator. For example, a composite porous layer in which alumina particles having a 90% particle size (D90) of less than 1 μm are bound using a fluororesin as a binder may be formed on the surface of the positive electrode.

-Electrolyte-
The electrolytic solution contains a solute (supporting salt) and a non-aqueous solvent, and further contains various additives as needed. The solute is usually dissolved in a non-aqueous solvent. The electrolyte is, for example, impregnated in the separator.

As the solute, those commonly used in this field can be used, for example, LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ _{, LiB 10} Cl. _10. Lower aliphatic carboxylic acid lithium, LiCl, LiBr, LiI, chloroborane lithium, borates, imide salts and the like can be mentioned. Examples of borates include bis (1,2-benzenediorate (2-) -O, O') lithium borate and bis (2,3-naphthalenedioleate (2-) -O, O') borate. Lithium, bis (2,2'-biphenyldiorate (2-) -O, O') lithium borate, bis (5-fluoro-2-olate-1-benzenesulfonic acid-O, O') lithium borate And so on. Examples of imide salts include imidelithium bistrifluoromethanesulfonate ((CF ₃ SO ₂ ) ₂ NLi) and imide lithium trifluoromethanesulfonate nonafluorobutane sulfonate ((CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) NLi). ), Imid lithium bispentafluoroethanesulfonate ((C ₂ F ₅ SO ₂ ) ₂ NLi) and the like. One type of solute may be used alone, or two or more types may be used in combination. The amount of the solute dissolved in a non-aqueous solvent is preferably 0.5 mol / L to 2 mol / L.

As the non-aqueous solvent, those commonly used in this field can be used, and examples thereof include cyclic carbonate ester, chain carbonate ester, and cyclic carboxylic acid ester. Examples of the cyclic carbonate include propylene carbonate (PC) and ethylene carbonate (EC). Examples of the chain carbonic acid ester include diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC) and the like. Examples of the cyclic carboxylic acid ester include γ-butyrolactone (GBL) and γ-valerolactone (GVL). One type of non-aqueous solvent may be used alone, or two or more types may be used in combination.

Further, from the viewpoint of further improving the battery characteristics, the non-aqueous solvent preferably contains vinylene carbonate (VC).

When vinylene carbonate (VC) is contained, the content is preferably 0.1% by mass to 2% by mass, and 0.2% by mass to 1.5% by mass, based on the total amount of the non-aqueous solvent. Is more preferable.

Hereinafter, embodiments in which the present disclosure is applied to a laminated lithium ion secondary battery will be described.

A laminated lithium ion secondary battery can be manufactured, for example, as follows. First, the positive electrode and the negative electrode are cut into a square shape, and tabs are welded to the respective electrodes to prepare positive electrode terminals and negative electrode terminals. An electrode laminate laminated with a separator interposed between the positive electrode and the negative electrode is produced, and in that state, the electrode laminate is housed in an aluminum laminate pack, and the positive electrode terminal and the negative electrode terminal are taken out of the aluminum laminate pack and sealed. Next, the electrolytic solution is poured into the aluminum laminate pack, and the opening of the aluminum laminate pack is sealed. As a result, a lithium ion secondary battery can be obtained.

Next, an embodiment in which the present disclosure is applied to an 18650 type columnar lithium ion secondary battery will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of a lithium ion secondary battery to which the present disclosure is applied.
As shown in FIG. 1, the lithium ion secondary battery 1 of the present disclosure has a battery container 6 made of nickel-plated steel and having a bottomed cylindrical shape. The battery container 6 houses an electrode group 5 in which a strip-shaped positive electrode plate 2 and a negative electrode plate 3 are wound in a spiral cross section via a separator 4. The separator 4 is set to, for example, a width of 58 mm and a thickness of 30 μm. A ribbon-shaped positive electrode tab terminal made of aluminum whose one end is fixed to the positive electrode plate 2 is led out from the upper end surface of the electrode group 5. The other end of the positive electrode tab terminal is arranged above the electrode group 5 and is ultrasonically bonded to the lower surface of the disk-shaped battery lid that serves as the positive electrode external terminal. On the other hand, on the lower end surface of the electrode group 5, a ribbon-shaped negative electrode tab terminal made of copper whose one end is fixed to the negative electrode plate 3 is led out. The other end of the negative electrode tab terminal is joined to the inner bottom of the battery container 6 by resistance welding. Therefore, the positive electrode tab terminal and the negative electrode tab terminal are led out to opposite sides of both end faces of the electrode group 5, respectively. The entire circumference of the outer peripheral surface of the electrode group 5 is provided with an insulating coating (not shown). The battery lid is caulked and fixed to the upper part of the battery container 6 via an insulating resin gasket. Therefore, the inside of the lithium ion secondary battery 1 is sealed. Further, an electrolytic solution (not shown) is injected into the battery container 6.

Hereinafter, the present disclosure will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

<Example 1>
(Synthesis of specific nitrile resin)
397.2 g of purified water was added to a 0.5 liter separable flask equipped with a stirrer, a thermometer, a cooling tube and a nitrogen introduction tube, the inside of the system was replaced with nitrogen, and the temperature was raised to 73.0 ° C. After dissolving 347.0 mg of ammonium persulfate in 2.5 g of purified water, the whole amount was added into the system. Next, as monomers in the system, 38.1 g of acrylonitrile (nitrile group-containing monomer, hereinafter sometimes referred to as AN) and methoxypolyethylene glycol acrylate (monomer described in formula (I), Shin-Nakamura Kagaku). AM-90G manufactured by Kogyo Co., Ltd., hereinafter may be referred to as AM-90G.) A mixture of 5.2 g was added dropwise over 2 hours and then reacted for 1 hour. After dissolving 420.0 mg of ammonium persulfate in 7.8 g of purified water, the whole amount was added into the system and reacted for 1 hour. Then, the temperature in the system was raised to 90.0 ° C., and the reaction was carried out over 1 hour. During the above step, the inside of the system was kept in a nitrogen atmosphere, and stirring was continued at 250 rpm. After cooling to room temperature (25 ° C.), the reaction solution was suction-filtered, and the precipitated resin was filtered off. The filtered resin was washed with 1000.0 g of purified water. The washed resin was dried in a vacuum dryer set at 60 ° C. and 150 Pa for 24 hours to obtain a specific nitrile resin. 423.0 g of N-methyl-2-pyrrolidone (hereinafter sometimes referred to as NMP) was added to a 0.5 liter separable flask equipped with a stirrer, a thermometer and a cooling tube, and the temperature was raised to 100 ° C. After that, 27.0 g of the specific nitrile resin powder was added, and the mixture was stirred at 300 rpm for 5 hours to prepare an NMP solution of the specific nitrile resin.

(Preparation of conductive carbon material dispersion for energy devices)
Carbon black (manufactured by Denka Co., Ltd., Li-435, primary particle size 23 nm (catalog value), hereinafter sometimes referred to as Li-435) in a special container for a disperser (Primix Co., Ltd., Fillmix FM-30L). 1.0 g and 8.3 g of an NMP solution of a specific nitrile resin were added, and NMP was further added so that the solid content concentration became 12.0% by mass (3.2 g in Example 1), and then Philmix FM-30L. Was stirred at a peripheral speed of 30 m / s for 30 seconds to obtain a conductive carbon material dispersion liquid 1 for an energy device.

<Example 2>
A conductive carbon material dispersion 2 for an energy device was obtained in the same manner as in Example 1 except that the stirring time in Fillmix FM-30L was changed from 30 seconds to 1 minute.

<Example 3>
A conductive carbon material dispersion 3 for an energy device was obtained in the same manner as in Example 1 except that the stirring time in Fillmix FM-30L was changed from 30 seconds to 3 minutes.

<Example 4>
A conductive carbon material dispersion 4 for an energy device was obtained in the same manner as in Example 1 except that the stirring time in Fillmix FM-30L was changed from 30 seconds to 5 minutes.

<Example 5>
A conductive carbon material dispersion 5 for an energy device was obtained in the same manner as in Example 1 except that the stirring time in Fillmix FM-30L was changed from 30 seconds to 10 minutes.

<Example 6>
A conductive carbon material dispersion 6 for an energy device was obtained in the same manner as in Example 3 except that 1.0 g of Li-435 and 2.3 g of an NMP solution of a specific nitrile resin were used.

<Example 7>
A conductive carbon material dispersion 7 for an energy device was obtained in the same manner as in Example 3 except that the amount of Li-435 was 1.0 g and the amount of the NMP solution of the specific nitrile resin was 6.5 g.

<Example 8>
A conductive carbon material dispersion 8 for an energy device was obtained in the same manner as in Example 3 except that Li-435 was 0.8 g and the NMP solution of the specific nitrile resin was 9.6 g.

<Example 9>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion liquid 9 for an energy device was obtained in the same manner as in Example 3 except that the reaction temperature was changed from 73.0 ° C. to 75.0 ° C.

<Example 10>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion liquid 10 for an energy device was obtained in the same manner as in Example 3 except that the reaction temperature was changed from 73.0 ° C. to 76.0 ° C.

<Example 11>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion 11 for an energy device was obtained in the same manner as in Example 3 except that the monomer was changed to a mixture of 37.2 g of AN and 6.1 g of AM-90G. ..

<Example 12>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion liquid 12 for an energy device was obtained in the same manner as in Example 3 except that the monomer was changed to a mixture of 39.0 g of AN and 4.3 g of AM-90G. ..

<Example 13>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion liquid 13 for an energy device was obtained in the same manner as in Example 3 except that the monomer was changed to a mixture of 39.8 g of AN and 3.5 g of AM-90G. ..

<Example 14>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion 14 for an energy device was obtained in the same manner as in Example 3 except that the monomer was changed to a mixture of 40.7 g of AN and 2.6 g of AM-90G. ..

<Example 15>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion 15 for an energy device was obtained in the same manner as in Example 3 except that the monomer was changed to a mixture of 42.0 g of AN and 1.3 g of AM-90G. ..

<Example 16>
In the synthesis of the specific nitrile resin, a conductive carbon material dispersion liquid 16 for an energy device was obtained in the same manner as in Example 3 except that the monomer was changed to 43.3 g of AN.

<Example 16-2>
A conductive carbon material dispersion liquid 16-2 for an energy device was obtained in the same manner as in Example 3 except that 1.0 g of Li-435 and 5.1 g of an NMP solution of a specific nitrile resin were used.

<Example 16-3>
A conductive carbon material dispersion liquid 16-3 for an energy device was obtained in the same manner as in Example 3 except that the amount of Li-435 was 0.8 g and the amount of the NMP solution of the specific nitrile resin was 8.0 g.

<Example 16-4>
A conductive carbon material dispersion liquid 16-4 for an energy device was obtained in the same manner as in Example 3 except that 0.7 g of Li-435 and 9.2 g of an NMP solution of a specific nitrile resin were used.

<Example 16-5>
Instead of Li-435, use 1.0 g of carbon black (manufactured by Denka Co., Ltd., Li-100, primary particle size 35 nm (catalog value), hereinafter sometimes referred to as Li-100), and use NMP solution 1 of a specific nitrile resin. A conductive carbon material dispersion 16-5 for an energy device was obtained in the same manner as in Example 3 except that the amount was .2 g.

<Example 16-6>
A conductive carbon material dispersion liquid 16-6 for an energy device was obtained in the same manner as in Example 3 except that Li-100 was 1.0 g instead of Li-435 and an NMP solution of a specific nitrile resin was 2.4 g. rice field.

<Example 16-7>
A conductive carbon material dispersion liquid 16-7 for an energy device was obtained in the same manner as in Example 3 except that Li-100 was 1.0 g instead of Li-435 and an NMP solution of a specific nitrile resin was 5.1 g. rice field.

<Example 16-8>
A conductive carbon material dispersion liquid 16-8 for an energy device was obtained in the same manner as in Example 3 except that Li-100 was 1.0 g instead of Li-435 and an NMP solution of a specific nitrile resin was 6.6 g. rice field.

<Example 16-9>
Instead of Li-435, use 1.5 g of carbon black (manufactured by Denka Co., Ltd., Li-400, primary particle size 48 nm (catalog value), hereinafter sometimes referred to as Li-400), and use NMP solution 0 of the specific nitrile resin. A conductive carbon material dispersion 16-9 for an energy device was obtained in the same manner as in Example 3 except that the amount was 9.9 g.

<Example 16-10>
A conductive carbon material dispersion liquid 16-10 for an energy device was obtained in the same manner as in Example 3 except that Li-400 was 1.0 g instead of Li-435 and an NMP solution of a specific nitrile resin was 1.2 g. rice field.

<Example 16-11>
A conductive carbon material dispersion for energy devices 16-11 was obtained in the same manner as in Example 3 except that Li-400 was 1.0 g instead of Li-435 and NMP solution of a specific nitrile resin was 2.4 g. rice field.

<Example 16-12>
A conductive carbon material dispersion for energy devices 16-12 was obtained in the same manner as in Example 3 except that Li-400 was 1.0 g instead of Li-435 and NMP solution of a specific nitrile resin was 5.1 g. rice field.

<Example 16-13>
Conductive carbon material dispersion liquid 16-13 for energy devices was obtained in the same manner as in Example 3 except that Li-400 was 1.0 g instead of Li-435 and the NMP solution of the specific nitrile resin was 6.6 g. rice field.

<Example 16-14>
Instead of Li-435, use 1.5 g of vapor-phase carbon fiber (Showa Denko Co., Ltd., VGCF-H, average length 6 μm, average diameter 150 nm, hereinafter sometimes referred to as VGCF-H), and use a specific nitrile resin. A conductive carbon material dispersion liquid 16-14 for an energy device was obtained in the same manner as in Example 3 except that the NMP solution was 0.9 g.

<Example 16-15>
A conductive carbon material dispersion liquid 16-15 for an energy device was obtained in the same manner as in Example 3 except that VGCF-H was 1.0 g instead of Li-435 and an NMP solution of a specific nitrile resin was 1.2 g. rice field.

<Example 16-16>
Conductive carbon material dispersion liquid 16-16 for energy devices was obtained in the same manner as in Example 3 except that VGCF-H was 1.0 g instead of Li-435 and NMP solution of the specific nitrile resin was 2.4 g. rice field.

<Comparative example 1>
A conductive carbon material dispersion C1 for an energy device was obtained in the same manner as in Example 1 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin.

<Comparative example 2>
A conductive carbon material dispersion C2 for an energy device was obtained in the same manner as in Example 2 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin.

<Comparative example 3>
A conductive carbon material dispersion C3 for an energy device was obtained in the same manner as in Example 3 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin.

<Comparative example 4>
A conductive carbon material dispersion C4 for an energy device was obtained in the same manner as in Example 4 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin.

<Comparative example 5>
A conductive carbon material dispersion C5 for an energy device was obtained in the same manner as in Example 5 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin.

<Comparative Example 5-2>
A conductive carbon material dispersion liquid C5-2 for an energy device was prepared in the same manner as in Example 3 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin and Li-100 was used instead of Li-435. Obtained.

<Comparative Example 5-3>
A conductive carbon material dispersion C5-3 for an energy device was prepared in the same manner as in Example 3 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin and Li-400 was used instead of Li-435. Obtained.

<Comparative Example 5-4>
A conductive carbon material dispersion liquid C5-4 for an energy device was prepared in the same manner as in Example 3 except that polyvinylidene fluoride (PVDF) was used instead of the specific nitrile resin and VGCF-H was used instead of Li-435. Obtained.

(Measurement of weight average molecular weight of specific nitrile resin)
The specific nitrile resin used in Examples 1 to 16 and the like is diluted with NMP so that the concentration becomes 0.1% by mass, and a filter made of PTFE (polytetrafluoroethylene) [manufactured by Kurashiki Spinning Co., Ltd., HPLC (high performance liquid)). Chromatography) Insoluble matter was removed through pretreatment, chromatodisc, model number: 13N, pore size: 0.45 μm]. GPC [Pump: L6200 Pump (manufactured by Hitachi, Ltd.), Detector: Differential refractometer detector L3300 RI Matter (manufactured by Hitachi, Ltd.), Columns: TSKgel-G5000HXL and TSKgel-G2000HXL (2 in total) (both Tosoh) (Manufactured by Co., Ltd.) were connected in series, and the weight average molecular weight was measured using a column temperature of 30 ° C., an eluent: N-methyl-2-pyrrolidone, a flow velocity: 1.0 mL / min, and a standard substance: polystyrene]. The results are shown in Tables 1 to 3.

(Evaluation of dispersibility of conductive carbon material dispersion for energy devices)
The dispersibility of the conductive carbon material dispersion liquid for energy devices according to Examples 1 to 16, Examples 16-2 to 16-16, Comparative Examples 1 to 5, and Comparative Examples 5-2 to 5-4 is observed in appearance. And evaluated based on the dispersed particle size. It was diluted with NMP so that the carbon black concentration or the VGCF-H concentration in the conductive carbon material dispersion for energy devices was 1.0% by mass. The diluted solution was visually observed to confirm the presence or absence of agglomerates. For those without agglomerates visually, the dispersed particle size was evaluated.
Examples and comparative examples using carbon black Li-435, Li-100 or Li-400 as the conductive carbon material are attached to a particle size distribution measuring instrument (Otsuka Electronics Co., Ltd., Zeta-potential & Liquidsize Analyzer, ELSZ). About 80% of the glass capacity was added to the glass cell of No. 1 and set in the measuring section of the particle size distribution measuring device, and the measurement was carried out 70 times. In the obtained number particle size distribution, the particle size (D50) was determined to be 50% when the number ratios were integrated from the one with the smallest particle size. This particle size (D50) corresponds to the dispersed particle size of carbon black. Dispersibility was evaluated according to the following criteria using visual appearance observation and dispersed particle size. It should be noted that A has the highest dispersibility and D has the lowest dispersibility.
A: Particle size (D50) is less than 1.0 μm B: Particle size (D50) is 1.0 μm or more and less than 3.0 μm C: Particle size (D50) is 3.0 μm or more D: Visually agglomerates Conductive For Examples and Comparative Examples in which VGCF-H was used as the sex carbon material, the dispersed particle size was determined in the same manner as in the case of carbon black, and dispersed according to the following criteria using visual appearance observation and the dispersed particle size. Gender was evaluated. It should be noted that A has the highest dispersibility and C has the lowest dispersibility.
A: Particle size (D50) is less than 7.0 μm B: Particle size (D50) is 7.0 μm or more and less than 10.0 μm C: Visually agglomerated

Examples 1 to 16 and 16-2 to 16-13 containing the specific nitrile resin are Comparative Examples 1 to 5, 5-2 or 5 containing PVDF, which is a resin containing no structural unit derived from a nitrile group-containing monomer. It can be seen that the dispersibility of carbon black, which is a conductive carbon material, is superior to that of -3. In Examples 3 and 11 to 16, the amount of the monomer represented by the formula (I) was changed, but since good dispersibility of the conductive carbon material was obtained in both cases, the conductivity was obtained. It is suggested that the improvement of the dispersibility of the carbon material is due to the effect of the structural unit derived from the nitrile group-containing monomer.
Examples 16-14 to 16-16 using VGCF-H as the conductive carbon material are compared with Comparative Example 5-4 containing PVDF, which is a resin containing no structural unit derived from a nitrile group-containing monomer. , It can be seen that the dispersibility of VGCF-H is excellent. From this, it can be seen that the specific nitrile resin is effective not only for carbon black but also for dispersion of vapor phase carbon fibers.

<Example 17>
(Preparation of composition for forming energy device electrodes (electrode slurry for energy devices))
After mixing the positive electrode active material (manufactured by Yumicore Japan Co., Ltd., MX6, hereinafter sometimes referred to as NMC) and the conductive carbon material dispersion liquid 3 for energy devices obtained in Example 3, the NMP solution of PVDF and An electrode slurry for an energy device was obtained by adding and mixing NMP for adjusting the viscosity. The solid content ratio (positive electrode active material: conductive carbon material: specific nitrile resin: PVDF) in the electrode slurry for energy devices was mixed so as to be 96% by mass: 2% by mass: 1% by mass: 1% by mass. ..

(Manufacturing of energy device electrodes)
The obtained electrode slurry for energy devices was applied evenly and uniformly to one side of an aluminum foil (current collector) having a thickness of 15 μm so that the coating amount after drying was 230 g / m ^2. Then, it was dried and rolled by a press to a density of 3.3 g / cm ³ to obtain an energy device electrode.

(Manufacturing of energy device)
In a stainless coin outer container having a diameter of 2.00 cm, an energy device electrode cut into a circle with a diameter of 1.50 cm and a separator made of a polyethylene microporous film having a thickness of 20 μm cut into a circle with a diameter of 1.80 cm are placed therein. Laminate in order and do not overflow the electrolytic solution (mixed solution of ethylene carbonate / ethylmethyl carbonate / dimethyl carbonate = _{2/2/3 (volume ratio) containing 1.20M LiPF 6 + vinylene carbonate 0.80% by mass).} A few drops were dropped. Further, metallic lithium cut into a circle with a diameter of 1.60 cm and a stainless plate with a thickness of 200 μm cut into a circle with a diameter of 1.60 cm as a spacer are stacked in this order, and a stainless cap is put on the metal via a polypropylene packing. , An energy device for evaluation was manufactured by sealing with a caulking machine for manufacturing a coin battery.

<Example 18>
Using the conductive carbon material dispersion for energy devices 6 obtained in Example 6, the solid content ratio (positive electrode active material: conductive carbon material: specific nitrile resin: PVDF) in the electrode slurry for energy devices was 96% by mass. An energy device for evaluation was produced in the same manner as in Example 17 except that it was changed to%: 2% by mass: 0.3% by mass: 1.7% by mass.

<Example 19>
Using the conductive carbon material dispersion for energy devices 7 obtained in Example 7, the solid content ratio (positive electrode active material: conductive carbon material: specific nitrile resin: PVDF) in the electrode slurry for energy devices was 96% by mass. An energy device for evaluation was produced in the same manner as in Example 17 except that the ratio was changed to%: 2% by mass: 0.8% by mass: 1.2% by mass.

<Example 20>
Using the conductive carbon material dispersion for energy devices 8 obtained in Example 8, the solid content ratio (positive electrode active material: conductive carbon material: specific nitrile resin: PVDF) in the electrode slurry for energy devices is 96 mass by mass. An energy device for evaluation was produced in the same manner as in Example 17 except that the ratio was changed to%: 2% by mass: 1.4% by mass: 0.6% by mass.

<Example 21>
An energy device for evaluation was produced in the same manner as in Example 18 except that the conductive carbon material dispersion liquid 11 for an energy device obtained in Example 11 was used.

<Example 22>
An energy device for evaluation was produced in the same manner as in Example 18 except that the conductive carbon material dispersion liquid 12 for an energy device obtained in Example 12 was used.

<Example 23>
An energy device for evaluation was produced in the same manner as in Example 18 except that the conductive carbon material dispersion liquid 13 for an energy device obtained in Example 13 was used.

<Example 24>
An energy device for evaluation was produced in the same manner as in Example 18 except that the conductive carbon material dispersion liquid 14 for an energy device obtained in Example 14 was used.

<Example 25>
An energy device for evaluation was produced in the same manner as in Example 18 except that the conductive carbon material dispersion liquid 15 for an energy device obtained in Example 15 was used.

<Example 26>
An energy device for evaluation was produced in the same manner as in Example 18 except that the conductive carbon material dispersion liquid 16 for an energy device obtained in Example 16 was used.

<Comparative Example 6>
Using the conductive carbon material dispersion C1 for energy devices obtained in Comparative Example 1, the solid content ratio (positive electrode active material: conductive carbon material: PVDF) in the electrode slurry for energy devices was 96% by mass: 2% by mass. %: An energy device for evaluation was produced in the same manner as in Example 17 except that the content was changed to 2% by mass.

<Comparative Example 7>
An energy device for evaluation was produced in the same manner as in Comparative Example 6 except that the conductive carbon material dispersion liquid C2 for an energy device obtained in Comparative Example 2 was used.

<Comparative Example 8>
An energy device for evaluation was produced in the same manner as in Comparative Example 6 except that the conductive carbon material dispersion liquid C3 for an energy device obtained in Comparative Example 3 was used.

<Comparative Example 9>
An energy device for evaluation was produced in the same manner as in Comparative Example 6 except that the conductive carbon material dispersion liquid C4 for an energy device obtained in Comparative Example 4 was used.

<Comparative Example 10>
An energy device for evaluation was produced in the same manner as in Comparative Example 6 except that the conductive carbon material dispersion liquid C5 for an energy device obtained in Comparative Example 5 was used.

(Initialization of evaluation energy device)
The prepared energy device for evaluation was placed in a constant temperature bath at 25.0 ° C. and connected to a charging / discharging device (Toyo System Co., Ltd., TOSCAT-3200). After a constant current charge of 0.10 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. Then, a constant current was discharged to 2.7 V at 0.10 C. This charging / discharging was repeated for 3 cycles to initialize the evaluation energy device. The unit "C" means "current value (A) / battery capacity (Ah)".

(Evaluation of output characteristics)
The initialized energy device for evaluation is placed in a constant temperature bath at 25.0 ° C., connected to a charging / discharging device (Toyo System Co., Ltd., TOSCAT-3200), and then charged / discharged in the order of (1) to (5) below. I let you.
(1) After a constant current charge of 0.20 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. A constant current discharge was performed up to 2.7 V with a current value of 0.20 C, and the discharge capacity was measured.
(2) After a constant current charge of 0.20 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. A constant current discharge was performed up to 2.7 V with a current value of 0.33 C, and the discharge capacity was measured.
(3) After a constant current charge of 0.20 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. A constant current discharge was performed up to 2.7 V with a current value of 0.50 C, and the discharge capacity was measured.
(4) After a constant current charge of 0.20 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. A constant current discharge was performed up to 2.7 V with a current value of 1.00 C, and the discharge capacity was measured.
(5) After a constant current charge of 0.20 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. A constant current discharge was performed up to 2.7 V at a current value of 3.00 C, and the discharge capacity was measured.

The maintenance rate was calculated by the following formula using the discharge capacity at 0.20 C and the discharge capacity at 3.00 C, and the output characteristics were evaluated according to the following criteria. It is shown that A has the best output characteristics and D has the worst output characteristics. The results are shown in Table 5.
Maintenance rate = Discharge capacity at 3.00C x Discharge capacity at 100 / 0.20C A: 85% or more B: 80% or more, less than 85% C: 75% or more, less than 80% D: less than 75%

(Evaluation of DC resistance)
The DC resistance was evaluated using the result of evaluating the output characteristics of the evaluation energy device.
The horizontal axis plots the current values during discharge of (1) to (5) above, and the vertical axis plots the voltage difference between before discharge and 5 seconds after the start of discharge, and the DC resistance is calculated from the slope.

(Evaluation of cycle characteristics)
The energy device whose output characteristics were evaluated was placed in a constant temperature bath at 25.0 ° C. and connected to a charging / discharging device (Toyo System Co., Ltd., TOSCAT-3200). After a constant current charge of 0.10 C to 4.2 V, a constant voltage charge was performed at 4.2 V until the current value became 0.01 C. A constant current discharge was performed at 0.10 C to 2.7 V, and the discharge capacity was measured. This charging / discharging was repeated 20 times. The DC resistance of the evaluation energy device after repeating charging and discharging 20 times was calculated by the above method, the DCR increase rate was calculated using the following formula, and the cycle characteristics were evaluated according to the following criteria. It is shown that A has the best cycle characteristics and C has the worst cycle characteristics. The results are shown in Table 2.
DCR increase rate = DC resistance before repeated charging / discharging x 100 / DC resistance after repeating charging / discharging A: Less than 180% B: 180% or more, less than 190% C: 190% or more

The disclosure of the international application PCT / JP2020 / 008361 filed on February 28, 2020 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims

A conductive carbon material dispersant for energy devices containing a resin containing a structural unit derived from a nitrile group-containing monomer.
The conductive carbon material dispersant for an energy device according to claim 1, wherein the resin further contains a structural unit derived from a monomer represented by the following formula (I).

[In formula (I), R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or a monovalent hydrocarbon group, and n represents an integer of 1 to 50. ]
The conductive carbon material dispersant for an energy device according to claim 1 or 2, wherein the structural unit derived from the nitrile group-containing monomer is contained in the main chain of the resin.
The energy device according to any one of claims 1 to 3, wherein the ratio of the structural unit derived from the nitrile group-containing monomer to the resin based on the mass is more than 80% by mass and 100% by mass or less. For conductive carbon material dispersant.
A conductive carbon material dispersion for an energy device containing a conductive carbon material, the conductive carbon material dispersant for an energy device according to any one of claims 1 to 4, and a solvent.
The conductive carbon material dispersion liquid for an energy device according to claim 5, wherein the average primary particle size of the conductive carbon material is 50 nm or less.
The conductive carbon material dispersion liquid for an energy device according to claim 5 or 6, wherein the conductive carbon material contains carbon black.
The conductive carbon material dispersion liquid for an energy device according to any one of claims 5 to 7, wherein the average particle size of the conductive carbon material is 0.3 μm to 3 μm.
The conductive carbon material dispersion liquid for an energy device according to claim 5, wherein the conductive carbon material contains carbon fibers.
The conductive carbon material dispersion for an energy device according to any one of claims 5 to 9, wherein the solvent contains at least one of N-methyl-2-pyrrolidone and γ-butyrolactone.
The dispersant contains a binder resin, an active material, a conductive carbon material, a dispersant for dispersing the conductive carbon material, and a solvent, and the dispersant is any one of claims 1 to 4. A composition for forming an energy device electrode, which comprises the conductive carbon material dispersant for an energy device according to.
A step of preparing an active material dispersion liquid by mixing the active material and the conductive carbon material dispersion liquid for an energy device according to any one of claims 5 to 10, and the active material dispersion liquid. A method for producing a composition for forming an energy device electrode, comprising a step of adding a binder resin.
The method for producing an energy device electrode forming composition according to claim 12, further comprising a step of adding a conductive carbon material to the active material dispersion liquid.
With the current collector
It is formed by using an energy device electrode forming composition provided on at least one surface of the current collector and produced by the method for producing an energy device electrode forming composition according to claim 12 or 13. With the electrode mixture layer
Energy device electrode with.
An energy device including the energy device electrode according to claim 14.