WO2018087897A1 - Resin for energy device electrodes, composition for forming energy device electrode, energy device electrode, and energy device - Google Patents

Abstract

This resin for energy device electrodes contains: a structural unit that is derived from a nitrile group-containing monomer; and a structural unit that is derived from a crosslinking agent containing at least two groups, each of which contains an ethylenically unsaturated double bond, in each molecule.

Description

Resin for energy device electrode, composition for forming energy device electrode, energy device electrode and energy device

The present invention relates to an energy device electrode resin, an energy device electrode forming composition, an energy device electrode, and an energy device.

As a power source for portable information terminals such as notebook computers and mobile phones, lithium ion secondary batteries are widely used as energy devices having high energy density.
In a typical lithium ion secondary battery, a positive electrode, a separator, a negative electrode, and a separator are stacked in this order, and a wound electrode group obtained by winding, or a stacked electrode formed by stacking a positive electrode, a separator, and a negative electrode Groups are used. As an active material of the negative electrode, a carbon material having a multilayer structure capable of inserting lithium ions between layers (forming a lithium intercalation compound) and releasing is mainly used. As the positive electrode active material, a lithium-containing composite metal oxide is mainly used. A polyolefin porous film is mainly used for the separator. Such a lithium ion secondary battery has high battery capacity and output, and good charge / discharge cycle characteristics.

The electrode of the lithium ion secondary battery is prepared by mixing the active material, binder resin and solvent (N-methyl-2-pyrrolidone, etc.) described above to prepare a slurry, which is then collected by a transfer roll or the like. It is applied to one or both sides of the metal foil, and the solvent is removed by drying to form an electrode mixture layer, and then compression-molded with a roll press or the like.
As the binder resin for the positive electrode, a fluorine resin having high reliability in terms of electrochemical stability is often used because of the high potential at the positive electrode. However, in general, the fluorine-based resin has low adhesion to other materials. Therefore, a resin material that exhibits high adhesion in a small amount and that can ensure electrochemical stability at the potential of the positive electrode is desired.
Further, the conventional binder resin has low swelling resistance to the electrolyte solution of lithium ion secondary battery (liquid that mediates the exchange of lithium ions between the positive electrode and the negative electrode due to charge / discharge), and the electrode mixture layer is formed by swelling. In some cases, the interface between the electrode and the current collector and the contact state between the active materials in the electrode mixture layer are difficult to be maintained. For this reason, when the conductive network in the electrode gradually collapses and the lithium ion secondary battery is repeatedly charged and discharged, this is a cause of a decrease in capacity over time.

As a solution to these problems, Patent Document 1 discloses a nitrile group-containing monomer, a relatively long-chain monomer including an oxyethylene skeleton responsible for flexibility and flexibility, and a relatively long-chain monomer. A binder resin composition for a non-aqueous electrolyte-based energy device electrode comprising a copolymer of at least one of monomers having a long alkyl group and any carboxy group-containing monomer responsible for adhesion is disclosed. .

Japanese Patent No. 4636444

By using the binder resin composition for non-aqueous electrolyte-based energy device electrodes disclosed in Patent Document 1, the swelling resistance to the electrolyte and the adhesion of the electrode to the current collector are improved, and the electrode Flexibility and flexibility tend to be good.
However, the rollability is low, and the electrode density after compression molding may not increase. Today, the demand for higher density energy devices is increasing, and materials with high rollability are desired.
In order to increase the electrode density after compression molding, the binder resin is required to have excellent rollability. In the present disclosure, “rollability” refers to a characteristic that the electrode density is easily improved by compression molding when forming the electrode. By increasing the electrode density by compression molding, the capacity of the lithium ion secondary battery can be increased.

This invention is made | formed in view of the said situation, and aims at providing the resin for energy device electrodes which is excellent in rolling property, and the composition for energy device electrode formation. Furthermore, this invention aims at providing the energy device electrode which shows high electrode density, and an energy device using the same.

The present invention relates to the following.
<1> a structural unit derived from a nitrile group-containing monomer;
A structural unit derived from a crosslinking agent containing at least two groups containing an ethylenically unsaturated double bond in one molecule;
Resin for energy device electrode containing.
<2> The energy device electrode resin according to <1>, wherein the group containing an ethylenically unsaturated double bond is at least one selected from the group consisting of an acryloyl group and a methacryloyl group.
<3> The energy device electrode resin according to <1> or <2>, wherein the crosslinking agent includes a compound represented by the following formula (I).

[In Formula (I), R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, R ₃ represents an alkylene group, and n represents an integer of 1 to 50. ]
<4> The energy device electrode resin according to <3>, wherein the compound represented by the formula (I) includes a compound represented by the following formula (II).

[In Formula (II), R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. ]
<5> The energy device electrode resin according to <4>, wherein the compound represented by the formula (II) includes triethylene glycol diacrylate.
<6> Any one of <1> to <5>, wherein a ratio of the structural unit derived from the crosslinking agent to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.0001 mol to 0.02 mol. The energy device electrode resin according to Item.
<7> The resin for energy device electrodes according to any one of <1> to <6>, further comprising a structural unit derived from a carboxy group-containing monomer and containing a carboxy group.
<8> The energy device electrode resin according to <7>, wherein the carboxy group-containing monomer contains acrylic acid.
<9> The ratio of the structural unit derived from the carboxy group-containing monomer and containing a carboxy group to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol < Resin for energy device electrodes as described in 7> or <8>.
<10> The energy device electrode resin according to any one of <1> to <9>, wherein the nitrile group-containing monomer includes acrylonitrile.
<11> The energy device electrode resin according to any one of <1> to <10>, further including a structural unit derived from a monomer represented by the following formula (III).

[In the formula (III), R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom or a monovalent hydrocarbon group, and m represents an integer of 1 to 50. ]
<12> The resin for energy device electrodes according to <11>, wherein R ₅ in the monomer represented by the formula (III) is an alkyl group or a phenyl group.
<13> The energy device electrode resin according to <11>, wherein the monomer represented by the formula (III) includes methoxytriethylene glycol acrylate.
<14> The ratio of the structural unit derived from the monomer represented by the formula (III) to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol <11 The resin for an energy device electrode according to any one of> to <13>.
<15> The energy device electrode resin according to any one of <1> to <14>, further comprising a structural unit derived from a monomer represented by the following formula (IV).

[In the formula (IV), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an alkyl group having 4 to 100 carbon atoms. ]
<16> The ratio of the structural unit derived from the monomer represented by the formula (IV) to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol <15 > Resin for energy device electrodes as described in>.
<17> An energy device electrode forming composition comprising the energy device electrode resin according to any one of <1> to <16>.
<18> The energy device electrode formation according to <17>, further including a positive electrode active material including a lithium-containing composite metal oxide having lithium and nickel and having a proportion of nickel in the metal excluding lithium of 50 mol% or more. Composition.
<19> The composition for forming an energy device electrode according to <18>, wherein the lithium-containing composite metal oxide includes a compound represented by the following formula (V).
_{Li a Ni b Co c M d} O 2 + e Formula (V)
[In Formula (V), M is at least one selected from the group consisting of Al, Mn, Mg and Ca, and a, b, c, d and e are 0.2 ≦ a ≦ 1. 2, 0.5 ≦ b ≦ 0.9, 0.1 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.2, −0.2 ≦ e ≦ 0.2 B + c + d = 1. ]
<20> current collector;
An electrode mixture layer provided on at least one surface of the current collector and formed from the composition for forming an energy device electrode according to any one of <17> to <19>;
Having energy device electrode.
<21> An energy device comprising the energy device electrode according to <20>.
<22> The energy device according to <21>, which is a lithium ion secondary battery.

According to the present invention, there are provided an energy device electrode resin and an energy device electrode forming composition excellent in rollability. Furthermore, according to this invention, the energy device electrode which shows high electrode density, and an energy device using the same are provided.

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

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention 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 numerical values and ranges thereof, and the present invention is not limited thereto.
In this specification, the term “process” includes a process that is independent of other processes and includes the process if the purpose of the process is achieved even if it cannot be clearly distinguished from the other processes. It is.
In the present specification, numerical values indicated by using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in this specification, 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. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present specification, the content of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. It means the content rate of.
In the present specification, the particle diameter of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
In this specification, the term “layer” or “film” refers to a part of the region in addition to the case where the layer or the film is formed when the region where the layer or film exists is observed. It is also included when it is formed only.
In this specification, the term “lamination” indicates that layers are stacked, and two or more layers may be combined, or two or more layers may be detachable.
In the present specification, “(meth) acryl” means at least one of acryl and methacryl, “(meth) acrylate” means at least one of acrylate and methacrylate, and “(meth) allyl” means at least one of allyl and methallyl. Mean one.

<Resin for energy device electrode>
The resin for energy device electrodes of the present disclosure comprises a structural unit derived from a nitrile group-containing monomer and a structural unit derived from a crosslinking agent containing at least two groups containing an ethylenically unsaturated double bond in one molecule. Including.

The resin for energy device electrodes of the present disclosure is excellent in rollability. The reason is not clear, but is presumed as follows.
As described above, when forming an electrode of a lithium ion secondary battery, the electrode mixture layer containing the binder resin, active material, etc. formed on the current collector is subjected to compression molding with a roll press or the like. Is done. In the electrode mixture layer, the active materials are considered to be bound by the binder resin. Therefore, at the time of compression molding, the active materials bound by the binder resin by pressurization are once separated, and the active materials are bound again with the density of the electrode mixture layer increased, It is considered that the active material is rearranged in the electrode mixture layer in a compressed state.
Since the resin for energy device electrodes of the present disclosure includes a structural unit derived from a crosslinking agent, it is considered that the adhesive force is low as compared with a resin not including a structural unit derived from a crosslinking agent. Therefore, it is considered that the binding force between the active materials when the resin for an energy device electrode of the present disclosure is used as a binder resin is lower than that of a resin not including a structural unit derived from a crosslinking agent. By using the energy device electrode resin of the present disclosure that binds the active materials with a weak binding force as the binder resin, the active materials are likely to be separated from each other during compression molding. Since the active materials are easily rearranged by being easily separated from each other, it is assumed that the density of the electrode mixture layer is easily improved and the rollability is improved.

In the present disclosure, “binder resin” refers to a resin having a function of binding particles such as active materials.

Hereinafter, components constituting the energy device electrode resin of the present disclosure will be described in detail.

-Nitrile group-containing monomer-
There is no restriction | limiting in particular as a nitrile group containing monomer used by this indication. Examples thereof include acrylic nitrile group-containing monomers such as acrylonitrile and methacrylonitrile, cyan nitrile group-containing monomers such as α-cyanoacrylate and dicyanovinylidene, and fumaric nitrile group-containing monomers such as fumaronitrile. It is done.
Among these, acrylonitrile or methacrylonitrile is preferable in terms of cost performance, electrode flexibility, flexibility, and the like, and acrylonitrile is more preferable in terms of ease of polymerization. The ratio of acrylonitrile in the nitrile group-containing monomer is, for example, preferably 50 mol% to 100 mol%, more preferably 80 mol% to 100 mol%, and even more preferably 100 mol%. preferable. One of these nitrile group-containing monomers may be used alone, or two or more thereof may be used in combination.
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 mass% to 95 mass% is more preferable.

-Crosslinking agent containing at least two groups containing ethylenically unsaturated double bonds in one molecule-
The crosslinking agent used in the present disclosure is not particularly limited as long as it contains at least two groups containing an ethylenically unsaturated double bond in one molecule. Hereinafter, a crosslinking agent containing at least two groups containing an ethylenically unsaturated double bond in one molecule may be referred to as a specific crosslinking agent.
There is no restriction | limiting in particular as group containing the ethylenically unsaturated double bond contained in a specific crosslinking agent. Examples thereof include polymerizable functional groups such as acryloyl group, methacryloyl group, vinyl group, styryl group, and allyl group. Among these, at least one selected from the group consisting of an acryloyl group and a methacryloyl group is preferable, and an acryloyl group is more preferable.
The number of groups containing an ethylenically unsaturated double bond contained in one molecule of the specific crosslinking agent is preferably 2 to 4, more preferably 2 to 3, More preferably it is.

The specific crosslinking agent preferably contains a compound represented by the following formula (I).

In formula (I), R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, preferably a hydrogen atom.
R ₃ represents an alkylene group, preferably an alkylene group having 1 to 20 carbon atoms. The alkylene group may have a linear structure or a branched structure. Moreover, even if it has a substituent, it may be unsubstituted. Examples of the substituent that may have include a halogen atom. The alkylene group is more preferably an unsubstituted alkylene group having 1 to 20 carbon atoms, more preferably an unsubstituted alkylene group having 1 to 10 carbon atoms, and an unsubstituted alkylene group having 2 to 6 carbon atoms. A substituted linear alkylene group is particularly preferred. Specific examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an octylene group, and a decylene group. Note that the carbon number of the alkylene group does not include the carbon number of the substituent.
n represents an integer of 1 to 50, preferably an integer of 2 to 30, and more preferably an integer of 2 to 10.

When the specific crosslinking agent contains a compound represented by formula (I), the structural unit derived from the compound represented by formula (I) occupies the structural unit derived from the specific crosslinking agent contained in the energy device electrode resin of the present disclosure. The ratio is preferably 50 mol% to 100 mol%, and more preferably 80 mol% to 100 mol%.

The compound represented by the formula (I) preferably includes a compound represented by the following formula (II).

In the formula (II), R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. Preferred ranges of R ₁ , R ₂ and n in the formula (II) are the same as in the case of the compound represented by the formula (I).
When the specific crosslinking agent contains a compound represented by formula (II), the structural unit derived from the compound represented by formula (II) occupies the structural unit derived from the specific crosslinking agent contained in the energy device electrode resin of the present disclosure. The ratio is preferably 50 mol% to 100 mol%, and more preferably 80 mol% to 100 mol%.

As the specific crosslinking agent, a commercially available product or a synthetic product may be used. Specific crosslinks available as commercial products are specifically triethylene glycol diacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-232A), nonanediol diacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-129AS), EO-modified bisphenol A diacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-324A), 1,4-butanediol dimethacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-124M), EO Modified bisphenol A dimethacrylate (trade name: FA-321M, manufactured by Hitachi Chemical Co., Ltd.), neopentyl glycol dimethacrylate (trade name: FA-125M, manufactured by Hitachi Chemical Co., Ltd.), 1,4-bis (acryloyloxy) butane (Manufactured by Tokyo Chemical Industry Co., Ltd.), 1,10-bis (acryloyloxy) de (Tokyo Chemical Industry Co., Ltd.), 1,6-bis (acryloyloxy) hexane (Tokyo Chemical Industry Co., Ltd.), 1,9-bis (acryloyloxy) nonane (Tokyo Chemical Industry Co., Ltd.), 1, 6-bis (acryloyloxy) -2,2,3,3,4,4,5,5-octafluorohexane (manufactured by Tokyo Chemical Industry Co., Ltd.), 1,5-bis (acryloyloxy) pentane (Tokyo Chemical Industry Co., Ltd.) Co., Ltd.), 1,3-butanediol dimethacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 1,6-hexanediol dimethacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) and the like. Among these, triethylene glycol diacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-232A) is preferable from the viewpoint of reactivity. These specific crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more type.

-Carboxy group-containing monomer-
In the present disclosure, a carboxy group-containing monomer may be used as necessary. There is no restriction | limiting in particular as a carboxy-group containing monomer used by this indication. Examples of the carboxy group-containing monomer include maleic monomers such as acrylic carboxy group-containing monomers such as acrylic acid and methacrylic acid, croton carboxy group-containing monomers such as crotonic acid, maleic acid, and anhydrides thereof. Examples include carboxy group-containing monomers, itaconic carboxy group-containing monomers such as itaconic acid and its anhydride, and citraconic carboxy group-containing monomers such as citraconic acid and its anhydride.
Among these, acrylic acid or methacrylic acid is preferable in terms of cost performance, electrode rollability, and the like, and acrylic acid is more preferable in terms of reactivity during polymerization. One of these carboxy group-containing monomers may be used alone, or two or more thereof may be used in combination. When acrylic acid and methacrylic acid are used in combination as the carboxy group-containing monomer, the acrylic acid content is preferably 5% by mass to 95% by mass with respect to the total amount of the carboxy group-containing monomer. 50% by mass to 95% by mass is more preferable.

-Monomer represented by the formula (III)-
In the present disclosure, a monomer represented by the following formula (III) may be used as necessary. There is no restriction | limiting in particular as a monomer represented by Formula (III) used by this indication.

In the formula (III), R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom or a monovalent hydrocarbon group, and m represents an integer of 1 to 50.

In formula (III), R ₄ represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom.
In the formula (III), m represents an integer of 1 to 50, preferably an integer of 2 to 30, and more preferably an integer of 2 to 10.
In formula (III), R ₅ represents a hydrogen atom or a monovalent hydrocarbon group, and is preferably a monovalent hydrocarbon group having 1 to 50 carbon atoms, for example, having 1 to 25 carbon atoms. The monovalent hydrocarbon group is more preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms.
If R ₅ is a hydrogen atom or a monovalent hydrocarbon group having 50 or less carbon atoms, sufficient swelling resistance to the electrolytic solution tends to be obtained. Here, examples of the hydrocarbon group include an alkyl group and a phenyl group. R ₅ is preferably an alkyl group or a phenyl group, and more preferably an alkyl group having 1 to 12 carbon atoms or a phenyl group. The alkyl group may be linear, branched or cyclic.
In the alkyl group and phenyl group represented by R ₅ , some hydrogen atoms may be substituted with a substituent. Examples of the substituent when R ₅ 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, and an aromatic ring. . Examples of the substituent when R ₅ is a phenyl 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 a carbon number. Examples thereof include 3 to 10 cycloalkyl groups. Note that the carbon number of the monovalent hydrocarbon group does not include the carbon number of the substituent.

As the monomer represented by the formula (III), a commercially available product or a synthetic product may be used. Specific examples of the monomer represented by the formula (III) available as a commercial product include ethoxydiethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate EC-A), methoxytriethylene, and the like. Glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate MTG-A and Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AM-30G), methoxypoly (n = 9) ethylene glycol acrylate (Kyoeisha Chemical Co., Ltd.) Product 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., trade name: NK ester AM-130G), methoxypoly (n = 3) Ethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AM-230G), octoxypoly (n = 18) ethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester A-OC) -18E), phenoxydiethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate P-200A and Shin Nakamura Chemical Co., Ltd., trade 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 (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate NP-4EA), nonylphenol EO addition Thing (n = ) Acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate NP-8EA), methoxydiethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester MC and Shin Nakamura Chemical Co., Ltd., trade name: NK Ester M -20G), methoxytriethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade 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) Manufactured by Kogyo Co., Ltd., trade name: NK ester M-90G), methoxypoly (n = 23) ethylene glycol methacrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester M-230G) and methoxypoly (n = 30) ethylene Glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester 041MA).
Among these, methoxytriethylene glycol acrylate (R _{4 in the} general formula (III) is a hydrogen atom, and R ₅ is a methyl group from the viewpoint of reactivity when copolymerized with a nitrile group-containing monomer. And a monomer wherein n is 3) is more preferred. One of these monomers represented by the general formula (III) may be used alone, or two or more thereof may be used in combination.

-Monomer represented by the formula (IV)-
In the present disclosure, a monomer represented by the following formula (IV) may be used as necessary. There is no restriction | limiting in particular as a monomer represented by Formula (IV) used by this indication.

In the formula (IV), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an alkyl group having 4 to 100 carbon atoms.

In the formula (IV), R ₇ is an alkyl group having 4 to 100 carbon atoms, preferably an alkyl group having 4 to 50 carbon atoms, more preferably an alkyl group having 6 to 30 carbon atoms. More preferably, it is an alkyl group having 8 to 15 carbon atoms.
If R ₇ is an alkyl group having 4 or more carbon atoms, sufficient flexibility tends to be obtained. When R ₇ is an alkyl group having 100 or less carbon atoms, sufficient swelling resistance to the electrolytic solution tends to be obtained.
The alkyl group represented by R ₇ may be linear, branched or cyclic.
In the alkyl group represented by R ₇ , some hydrogen atoms may be substituted with a substituent. Examples of the substituent include halogen atoms such as a fluorine atom, chlorine atom, bromine atom and iodine atom, a substituent containing a nitrogen atom, a substituent containing a phosphorus atom, and an aromatic ring. For example, examples of the alkyl group represented by R ₇ include linear or branched saturated alkyl groups, and halogenated alkyl groups such as fluoroalkyl groups, chloroalkyl groups, bromoalkyl groups, and iodide iodide groups. . Note that the carbon number of the alkyl group does not include the carbon number of the substituent.

As the monomer represented by the formula (IV), a commercially available product or a synthetic product may be used. Specific examples of commercially available monomers represented by formula (IV) 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 Long chain (meth) acrylic acid esters such relations are exemplified.
When R ₇ is a fluoroalkyl group, 1,1-bis (trifluoromethyl) -2,2,2-trifluoroethyl acrylate, 2,2,3,3,4,4,4-heptafluoro Butyl acrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, nonafluoroisobutyl acrylate, 2,2,3,3,4,4,5,5-octafluoropentyl acrylate, 2,2 , 3,3,4,4,5,5,5-nonafluoropentyl acrylate, 2,2,3,3,4,4,5,5,6,6,6-undecafluorohexyl acrylate, 2, 2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl acrylate, 3,3,4,4,5,5,6,6 7, 7, 8, 8, 9, 9, 10, 10, 10-heptadecafluorodecyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-nonadecafluorodecyl Acrylate compounds such as acrylate, nonafluoro-t-butyl methacrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2,2,3,3,4,4,5,5-octafluoro Pentyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate, heptadecafluorooctyl methacrylate, 2,2,3,3,4,4 5,5,6,6,7,7,8,8,8-pentadecafluorooctyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8, 8,9,9-Hexadecaful Methacrylate compounds of b nonyl methacrylate, and the like.
One of these monomers represented by the general formula (IV) may be used alone, or two or more thereof may be used in combination.

-Other monomers-
The resin for energy device electrodes of the present disclosure comprises a structural unit derived from a nitrile group-containing monomer and a structural unit derived from a crosslinking agent containing at least two groups containing an ethylenically unsaturated double bond in one molecule. If included, structural units derived from other monomers different from these monomers can be appropriately combined.
Other monomers are not particularly limited, and short chain (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, vinyl chloride, bromide Vinyl halides such as vinyl and vinylidene chloride, maleic acid imide, phenylmaleimide, (meth) acrylamide, styrene, α-methylstyrene, vinyl acetate, sodium (meth) allylsulfonate, sodium (meth) allyloxybenzenesulfonate , Sodium styrenesulfonate, 2-acrylamido-2-methylpropanesulfonic acid and its salts. These other monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

-Ratio of structural units derived from each monomer and crosslinking agent-
The ratio of the structural units derived from the respective monomers contained in the energy device electrode resin of the present disclosure is not particularly limited.
The ratio of the structural unit derived from the nitrile group-containing monomer to the structural unit derived from each monomer contained in the energy device electrode resin of the present disclosure is preferably 50 mol% to 99.8 mol%. 80 mol% to 99.5 mol% is more preferable, and 90 mol to 99.3 mol% is still more preferable.
The ratio of the structural unit derived from the specific crosslinking agent to 1 mol of the structural unit derived from the nitrile group-containing monomer is preferably 0.0001 mol to 0.02 mol, and preferably 0.0001 mol to 0.01 mol. More preferred is 0.0001 mol to 0.005 mol. When the ratio of the structural unit derived from the specific cross-linking agent is 0.0001 mol to 0.02 mol, gelation can be suppressed during synthesis, adhesion to the current collector, and swelling resistance to the electrolyte The electrode tends to have good rolling properties.
When the resin for energy device electrode of the present disclosure is derived from a carboxy group-containing monomer and contains a structural unit containing a carboxy group, derived from a carboxy group-containing monomer with respect to 1 mol of a structural unit derived from a nitrile group-containing monomer The ratio of the structural unit containing a carboxy group is preferably 0.001 mol to 0.2 mol, more preferably 0.001 mol to 0.1 mol, and 0.001 mol to 0 mol. More preferably, it is 0.05 mole.

When the structural unit derived from the monomer represented by the formula (III) is contained in the energy device electrode resin of the present disclosure, the structural unit represented by the formula (III) with respect to 1 mol of the structural unit derived from the nitrile group-containing monomer. The ratio of structural units derived from monomers is, for example, preferably 0.001 mol to 0.2 mol, more preferably 0.003 mol to 0.05 mol, and 0.005 mol to 0 mol. More preferably, it is 0.02 mol. If the ratio of the structural unit derived from the monomer represented by the formula (III) is 0.001 mol to 0.2 mol, the swelling resistance to the electrolytic solution is excellent and the rolling property of the electrode tends to be better. It is in.

When the structural unit derived from the monomer represented by the formula (IV) is contained in the energy device electrode resin of the present disclosure, the resin is represented by the formula (IV) with respect to 1 mol of the structural unit derived from the nitrile group-containing monomer. The ratio of structural units derived from monomers is, for example, preferably 0.001 mol to 0.2 mol, more preferably 0.003 mol to 0.05 mol, and 0.005 mol to 0 mol. More preferably, it is 0.02 mol. If the ratio of the structural unit derived from the monomer represented by the formula (IV) is 0.001 mol to 0.2 mol, the swelling resistance to the electrolytic solution is excellent and the rolling property of the electrode tends to be better. It is in.

When the energy device electrode resin of the present disclosure contains structural units derived from other monomers, the ratio of structural units derived from other monomers to 1 mol of structural units derived from a nitrile group-containing monomer is, for example, 0.005 mol to 0.1 mol is preferable, 0.01 mol to 0.06 mol is more preferable, and 0.03 mol to 0.05 mol is more preferable.

-Manufacturing method of resin for energy device electrode-
The method for producing the energy device electrode resin of the present disclosure is not particularly limited. Polymerization methods such as precipitation polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization can be applied. Precipitation polymerization in water is preferred in terms of ease of resin synthesis, ease of post-treatment such as recovery and purification.
Hereinafter, the precipitation polymerization in water will be described in detail.

-Polymerization initiator-
As a polymerization initiator for performing precipitation polymerization in water, a water-soluble polymerization initiator is preferably used in view of polymerization initiation efficiency and the like.
Water-soluble polymerization initiators include persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate, water-soluble peroxides such as hydrogen peroxide, 2,2′-azobis (2-methylpropionamidine hydrochloride) Combined with water-soluble azo compounds such as persulfate, etc. and reducing agents such as sodium bisulfite, ammonium bisulfite, sodium thiosulfate, hydrosulfite and polymerization accelerators such as sulfuric acid, iron sulfate, copper sulfate Examples include redox type (redox type).
Of these, persulfates, water-soluble azo compounds, and the like are preferable in terms of ease of resin synthesis. Of the persulfates, ammonium persulfate is particularly preferred.
In addition, when acrylonitrile is selected as the nitrile group-containing monomer and methoxytriethylene glycol acrylate is selected as the monomer represented by the formula (III) to be used as necessary, water precipitation polymerization is performed. Since both are water-soluble in the state of a monomer, a water-soluble polymerization initiator acts effectively and polymerization starts smoothly. And since a polymer precipitates as superposition | polymerization progresses, a reaction system will be in a suspended state, and resin for energy device electrodes with few unreacted substances will be finally obtained with a high yield.
The polymerization initiator is preferably used, for example, in the range of 0.001 mol% to 5 mol% with respect to the total amount of monomers used for the synthesis of the energy device electrode resin, 0.01 mol% More preferably, it is used in the range of ˜2 mol%.

-Chain transfer agent-
When carrying out precipitation polymerization in water, a chain transfer agent can be used for the purpose of adjusting the molecular weight. 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 from the viewpoint of low odor.

-solvent-
When performing precipitation polymerization in water, a solvent other than water can be added as necessary, for example, by adjusting the particle diameter of the precipitated resin.
Examples of solvents other than water include amides such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, N-dimethylethyleneurea, N, N-dimethylpropyleneurea, tetra Ureas such as methylurea, lactones such as γ-butyrolactone and γ-caprolactone, carbonates such as propylene carbonate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate , Esters such as butyl cellosolve acetate, butyl carbitol acetate, ethyl cellosolve acetate and ethyl carbitol acetate, glymes such as diglyme, triglyme and tetraglyme, carbonized such as toluene, xylene and cyclohexane Examples include hydrogens, sulfoxides such as dimethyl sulfoxide, sulfones such as sulfolane, alcohols such as methanol, isopropanol, and n-butanol. These solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

-Polymerization conditions-
In the precipitation polymerization in water, for example, a monomer is introduced into a solvent, and the polymerization temperature is preferably 0 to 100 ° C., more preferably 30 to 90 ° C., preferably 1 to 50 hours, more preferably 2 By holding for 12 hours.
If 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 it becomes difficult to perform polymerization.
In particular, since the polymerization heat of the nitrile group-containing monomer tends to be large, it is preferable to proceed the polymerization while dropping the nitrile group-containing monomer into the solvent.

The weight average molecular weight of the energy device electrode resin of the present disclosure is preferably 10,000 to 1,000,000, more preferably 100,000 to 800,000, and still more preferably 250,000 to 700,000.
In the present disclosure, the weight average molecular weight is a value measured by the following method.
A measurement object is dissolved in N-methyl-2-pyrrolidone, and a PTFE (polytetrafluoroethylene) filter (manufactured by Kurashiki Boseki Co., Ltd., HPLC (high performance liquid chromatography) pretreatment, chromatodisc, model number: 13N, pore size: 0.45 μm] to remove insoluble matter. GPC (pump: L6200 Pump (manufactured by Hitachi, Ltd.), detector: differential refractive index detector L3300 RI Monitor (manufactured by Hitachi, Ltd.), column: TSKgel-G5000HXL and TSKgel-G2000HXL (both in total) (Manufactured by Co., Ltd.) in series, column temperature: 30 ° C., eluent: N-methyl-2-pyrrolidone, flow rate: 1.0 ml / min, standard material: polystyrene], and the weight average molecular weight is measured.

The acid value of the energy device electrode resin of the present disclosure is preferably 0 mgKOH / g to 70 mgKOH / g, more preferably 0 mgKOH / g to 20 mgKOH / g, and 0 mgKOH / g to 5 mgKOH / g. Is more preferable.
In the present disclosure, the acid value refers to a value measured by the following method.
First, after precisely weighing 1 g of a measurement object, 30 g of acetone is added to the measurement object, and the measurement object is dissolved. Next, an appropriate amount of an indicator, phenolphthalein, is added to the solution to be measured and titrated with a 0.1N aqueous KOH solution. Then, the acid value is calculated from the titration result by the following formula (A) (where Vf represents the titration amount (mL) of phenolphthalein, Wp represents the mass (g) of the solution to be measured, and I represents (The ratio (% by mass) of the nonvolatile content of the solution to be measured is shown.)
Acid value (mgKOH / g) = 10 × Vf × 56.1 / (Wp × I) (A)
The nonvolatile content of the solution to be measured is calculated from the residue mass by weighing 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.

-Applications of resin for energy device electrodes-
The resin for an energy device electrode of the present disclosure is suitably used for an energy device, particularly a non-aqueous electrolyte type energy device. A non-aqueous electrolyte-based energy device refers to a power storage or power generation device (apparatus) that uses an electrolyte other than water.
Examples of the energy device include a lithium ion secondary battery, an electric double layer capacitor, a solar cell, and a fuel cell. The energy device electrode resin of the present disclosure has high swelling resistance against a non-aqueous electrolyte solution such as an organic solvent other than water, and is preferably used in an electrode of a lithium ion secondary battery.
In addition, the resin for energy device electrodes of the present disclosure is not limited to energy devices, but includes paints, adhesives, curing agents, printing inks, solder resists, abrasives, electronic component sealants, semiconductor surface protective films, and interlayer insulation. It can be widely used for various coating resins such as membranes, varnishes for electrical insulation and biomaterials, molding materials and fibers.

<Composition for energy device electrode formation>
The composition for energy device electrode formation of this indication contains resin for energy device electrodes of this indication.
The composition for energy device electrode formation of this indication should just contain resin for energy device electrodes of this indication, and may contain various other ingredients if needed.

-solvent-
When the composition for forming an energy device electrode of the present disclosure is handled as a slurry, the composition for forming an energy device electrode of the present disclosure preferably includes a solvent.
There is no restriction | limiting in particular as a solvent used for preparation of the composition for slurry-like energy device electrode formation, For example, the solvent, water, etc. which can be added when performing precipitation polymerization in water mentioned above can be used. Of these, amide solvents, urea solvents, lactone solvents, and the like or mixed solvents containing them are preferable from the viewpoint of solubility of the energy device electrode resin, and N-methyl-2-pyrrolidone, γ-butyrolactone is preferable. Or the mixed solvent containing them is more preferable. These solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the solvent is not particularly limited as long as it is equal to or higher than a necessary minimum amount capable of maintaining the dissolved state of the energy device electrode resin at room temperature (for example, 25 ° C.). In addition, in the slurry preparation process in electrode production of an energy device, since viscosity adjustment is normally performed while adding a solvent, it is preferable to set it as the arbitrary quantity which is not diluted too much more than necessary.

When the composition for forming an energy device electrode of the present disclosure contains a solvent, the viscosity at 25 ° C. is preferably 500 mPa · s to 50000 mPa · s, more preferably 1000 mPa · s to 20000 mPa · s, and 2000 mPa · s. More preferably, it is s to 10,000 mPa · s.
The viscosity is measured at 25 ° C. and a shear rate of 1.0 s ⁻¹ using a rotary shear viscometer.

-Active material-
The composition for forming an energy device electrode 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, for example, charging and discharging of a lithium ion secondary battery that 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. For this reason, as the active material used in the positive electrode and the negative electrode, materials that are suitable for the respective functions are usually used.

As an active material (negative electrode active material) used for a negative electrode of a lithium ion secondary battery, a material capable of occluding and releasing lithium ions, which is commonly used in the field of lithium ion secondary batteries can be used. Examples of the negative electrode active material include lithium metal, lithium alloy, intermetallic compound, carbon material, metal complex, and organic polymer compound. A negative electrode active material may be used individually by 1 type, and may be used in combination of 2 or more type. Among these, a carbon material is preferable. Examples of the carbon material include graphite such as natural graphite (such as flake graphite) and artificial graphite, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black, and carbon fiber. The average particle size of the carbon 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 carbon material is preferably 1 m ² / g to 10 m ² / g.

Among carbon materials, in particular, from the viewpoint of further improving battery characteristics, graphite having a carbon hexagonal plane spacing (d ₀₀₂ ) of 3.35 to 3.40 and a c-axis direction crystallite (Lc) of 100 or more. Is preferred.
Further, among carbon materials, in particular, from the viewpoint of further improving cycle characteristics and safety, amorphous carbon having an interval (d ₀₀₂ ) between carbon hexagonal planes in the X-ray wide angle diffraction method of 3.50 mm to 3.95 mm is used. Is preferred.

In this specification, the average particle size is a volume-based particle size measured by dispersing a sample in purified water containing a surfactant and measuring with a laser diffraction particle size distribution analyzer (for example, SALD-3000J manufactured by Shimadzu Corporation). In the distribution, the value when the integration from the small diameter side becomes 50% (median diameter (D50)) is used.
A BET specific surface area can be measured from nitrogen adsorption capacity according to JIS Z 8830: 2013, for example. As the evaluation apparatus, for example, AUTOSORB-1 (trade name) manufactured by QUANTACHROME can be used. Since water adsorbed on the sample surface and in the structure is considered to affect the gas adsorption capacity, it is preferable to first perform pretreatment for removing water by heating when measuring the BET specific surface area.
In the pretreatment, a measurement cell charged with 0.05 g of a measurement sample is depressurized to 10 Pa or less with a vacuum pump, heated at 110 ° C. and held for 3 hours or more, and then kept at a normal temperature ( Cool to 25 ° C). After performing this pretreatment, the evaluation temperature is 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 an active material (positive electrode active material) used for a positive electrode of a lithium ion secondary battery, those commonly used in this field can be used. For example, a lithium-containing composite metal oxide, an olivine type lithium salt, a chalcogen compound, Examples include manganese dioxide. The lithium-containing composite metal 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 substituted with a different element. Here, examples of the different element include Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, V, and B. Mn, Al, Co, Ni, Mg and the like are preferable. Different elements may be used alone or in combination of two or more.

Examples of the lithium-containing composite metal 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 O _z , 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 ), Li _x Ni _1-y M ² _y O _z (in Li _x Ni _1-y M ² _y O _z , M ² is Na, Mg, Sc, Y, Mn, Fe, Co, And 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 and Li _x Mn _2-y M ³ _y O ₄ ( In Li _x Mn _2-y M ³ _y O ₄ , M ³ is Na, Mg, And at least one element selected from the group consisting of Sc, Y, Fe, Co, Cu, Zn, Al, Cr, Pb, Sb, V, and B.). 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 due to charge / discharge. _Furthermore, it includes _{Li 1 Ni 1/3 Mn 1/3 Co 1/3} O 2.
Further, as the olivine type lithium salts, for example, LiFePO _4, and the like. Examples of the chalcogen compound include titanium disulfide and molybdenum disulfide. As other positive electrode active materials, 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 B represents at least one element selected from the group consisting of B). A positive electrode active material may be used individually by 1 type, and may be used in combination of 2 or more type.

As the positive electrode active material, it is preferable to use a lithium-containing composite metal oxide that has lithium and nickel and has a nickel content of 50 mol% or more in the metal excluding lithium.
When a resin composition is produced by applying PVDF, which is widely used as a binder resin, to a positive electrode active material in which the proportion of nickel in the metal excluding lithium is 50 mol% or more, the resin composition may be gelled. On the other hand, when the resin for energy device electrodes of the present disclosure is used as a binder resin, the gelation of the resin composition tends to be suppressed.

In particular, in order to increase the charge / discharge capacity per unit mass in the positive electrode active material and to obtain a high capacity positive electrode for energy devices, the positive electrode active material is represented by the following formula (V). It is preferable to use a positive electrode active material.
_{Li a Ni b Co c M d} O 2 + e Formula (V)
In the formula (V), M is at least one selected from the group consisting of Al, Mn, Mg and Ca, and a, b, c, d and e are each 0.2 ≦ a ≦ 1.2. 0.5 ≦ b ≦ 0.9, 0.1 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.2, −0.2 ≦ e ≦ 0.2, b + c + d = 1.

As the Ni ratio increases, the capacity density of the positive electrode active material increases. As the Ni ratio decreases, the thermodynamic stability of the positive electrode active material increases. Therefore, the Ni ratio is 0.5 ≦ b ≦. 0.9 is preferable, 0.55 ≦ b ≦ 0.85 is more preferable, and 0.6 ≦ b ≦ 0.8 is further more preferable. Moreover, since the discharge performance of a positive electrode active material improves, so that the ratio of Co becomes large, and the capacity density of a positive electrode active material becomes large, so that the ratio of Co is small, 0.1 <= c <= 0.4 is preferable.

Further, M in the formula (V) can contain at least one selected from the group consisting of Al, Mn, Mg and Ca. When such an element is contained, it is possible to increase the thermodynamic stability of the positive electrode active material and to suppress an increase in resistance caused by nickel entering the lithium site. On the other hand, the smaller the ratio of M, the larger the capacity density of the positive electrode active material. From such a viewpoint, the ratio of M is preferably 0 ≦ d ≦ 0.2.

The positive electrode active material represented by the formula (V) can be produced by a method commonly used in this field. An example of production is shown below.

First, a metal salt solution of a metal to be introduced into the positive electrode active material is prepared. As the metal salt, those commonly used in the art can be used, and examples thereof include sulfates, chloride salts, nitrates and acetates.
Among them, nitrate is preferable because it functions as an oxidant in the subsequent firing step, so that the oxidation of the metal in the firing raw material is easily promoted, and it is difficult to remain because it volatilizes by firing. The molar ratio of each metal contained in the metal salt solution is preferably equal to the molar ratio of each metal of the positive electrode active material to be produced.

Next, the lithium source is suspended in pure water. As the lithium source, those commonly used in this field can be used, and examples include lithium carbonate, lithium nitrate, lithium hydroxide, lithium acetate, alkyl lithium, fatty acid lithium, and lithium lithium. Then, the metal salt solution of the said metal is added and lithium salt solution slurry is produced. At this time, fine lithium-containing carbonate precipitates in the slurry. The average particle diameter of the lithium-containing carbonate in the slurry can be adjusted by the shear rate of the slurry. The precipitated lithium-containing carbonate is filtered off and dried to obtain a precursor of the positive electrode active material.

The obtained lithium-containing carbonate is filled in a firing container and fired in a firing furnace. Firing is preferably held in a heated state for a predetermined time in an oxygen-containing atmosphere, preferably in an oxygen atmosphere. Further, the firing is preferably performed under a pressure of 101 kPa to 202 kPa. The amount of oxygen in the composition can be increased by heating under pressure. The firing temperature is preferably 850 ° C. to 1200 ° C., more preferably 850 ° C. to 1100 ° C., and further preferably 850 ° C. to 1000 ° C. When firing in such a temperature range, the crystallinity of the positive electrode active material tends to be improved.

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. Further, the BET specific surface area of the positive electrode active material is preferably 1 m ² / g to 10 m ² / g.

-Conductive agent-
A conductive agent may be used in combination with the active material.
As the conductive agent, for example, carbon black, graphite, carbon fiber, metal fiber, or the like can be used. Examples of carbon black include acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. Examples of graphite include natural graphite and artificial graphite. A conductive agent may be used individually by 1 type, and may be used in combination of 2 or more type.

-Other additives-
In the composition for forming an energy device electrode of the present disclosure, a crosslinking component for supplementing swelling resistance to other materials, for example, an electrolyte solution, and flexibility and flexibility of the electrode, as necessary. Various additives such as an anti-settling agent, an antifoaming agent, a leveling agent and the like for improving the rubber component and the electrode coatability of the slurry can also be blended.

<Energy device electrode>
The energy device electrode of the present disclosure includes a current collector, and an electrode mixture layer provided on at least one surface of the current collector and formed from the composition for forming an energy device electrode of the present disclosure.
The energy device electrode of the present disclosure can be used as an electrode of a lithium ion secondary battery, an electric double layer capacitor, a solar cell, a fuel cell, or the like.
Hereinafter, a case where the energy device electrode of the present disclosure is applied to an electrode of a lithium ion secondary battery will be described in detail. However, 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 lithium ion secondary batteries 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 foil is not particularly limited, and is preferably 1 μm to 500 μm, more preferably 2 μm to 80 μm, and more preferably 5 μm, from the viewpoint of ensuring the strength and workability required for the current collector. More preferably, it is ˜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 foil is not particularly limited, and is preferably 1 μm to 500 μm, more preferably 2 μm to 100 μm, and more preferably 5 μm from the viewpoint of ensuring the strength and workability required for the current collector. More preferably, it is ˜50 μm.

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

The electrode mixture layer is prepared, for example, by preparing a slurry of the composition for forming an energy device electrode, applying the slurry onto at least one surface of the current collector, and then drying and removing the solvent. It can be formed by rolling.
The application of the slurry can be performed using, for example, a comma coater. The coating is suitably performed so that the ratio between the positive electrode capacity and the negative electrode capacity (negative electrode capacity / positive electrode capacity) is 1 or more in the opposing electrode.
The amount of slurry applied is, for example, preferably an amount such that the dry mass of the electrode mixture layer is 5 g / m ² to 30 g / m ^2, and is an amount such that 10 g / m ² to 15 g / m ^2. Is more preferable.
The removal of the solvent is performed, for example, by drying at preferably 50 ° C. to 150 ° C., more preferably 80 ° C. to 120 ° C., preferably 1 minute to 20 minutes, more preferably 3 minutes to 10 minutes.
Rolling is performed using, for example, a roll press, and when the density of the electrode mixture layer is a negative electrode mixture layer, for example, 1 g / cm ³ to 2 g / cm ³ , preferably 1.2 g / cm ³ to as will be 1.8 g / cm ^3, when the positive electrode mixture layer, for ^{example, 2g / cm 3 ~ 5g /} cm 3, preferably, is pressed so that ^{3g / cm 3 ~ 4g / cm} 3.
Furthermore, in order to remove the residual solvent and adsorbed water in the electrode mixture layer, 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 includes 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, and a fuel cell. The energy device of the present disclosure is preferably applied to a non-aqueous electrolyte-based energy device. A non-aqueous electrolyte-based energy device refers to a power storage or power generation device (apparatus) that uses an electrolyte other than water.
Hereinafter, although the case where the energy device is a lithium ion secondary battery will be described in detail, 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 electrode of the present disclosure is used as at least one of the positive electrode and the negative electrode. Since the energy device electrode of the present disclosure includes the energy device electrode resin of the present disclosure as a binder resin, the discharge capacity is improved and gas generation tends to be suppressed. The reason for this is not clear, but the energy device electrode resin of the present disclosure forms a film having excellent ion permeability with respect to the components of the energy device electrode such as an active material and a conductive agent, and suppresses decomposition of the electrolyte. It is guessed that this is because.
In addition, when electrodes other than the energy device electrode of the present disclosure are used as one of the positive electrode and the negative electrode, those commonly used in this field can be used.

-Separator-
The separator is not particularly limited as long as it has ion permeability while electronically insulating between the positive electrode and the negative electrode, and has resistance to oxidation on the positive electrode side and reducibility on the negative electrode side. As a material (material) of the separator that satisfies such characteristics, a resin, an inorganic substance, or the like is used.

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

Examples of inorganic substances include oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, sulfates such as barium sulfate and calcium sulfate, and glass. For example, what made the said inorganic substance of fiber shape or particle shape adhere to thin film-shaped base materials, such as a nonwoven fabric, a woven fabric, and a microporous film, can be used as a separator.
As the thin film-shaped substrate, a substrate having a pore diameter of 0.01 μm to 1 μm and a thickness of 5 μm to 50 μm is preferably used. In addition, for example, a separator in which a composite porous layer is formed using the above-described inorganic material in a fiber shape or a particle shape by using a binder such as a resin can be used as a separator. Furthermore, this composite porous layer may be formed on the surface of the positive electrode or the negative electrode to form a separator. For example, a composite porous layer in which alumina particles having a 90% particle diameter (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 nonaqueous solvent, and further contains various additives as necessary. Solutes usually dissolve in non-aqueous solvents. For example, the electrolytic solution is 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 lithium carboxylates, LiCl, LiBr, LiI, chloroborane lithium, borates, imide salts and the like. Examples of borates include lithium bis (1,2-benzenediolate (2-)-O, O ′) borate, bis (2,3-naphthalenedioleate (2-)-O, O ′) boric acid. Lithium, bis (2,2′-biphenyldiolate (2-)-O, O ′) lithium borate, bis (5-fluoro-2-olate-1-benzenesulfonic acid-O, O ′) lithium borate Etc. Examples of imide salts include lithium bistrifluoromethanesulfonate imide ((CF ₃ SO ₂ ) ₂ NLi), lithium trifluoromethanesulfonate nonafluorobutanesulfonate ((CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) NLi ), Lithium bispentafluoroethanesulfonate imide ((C ₂ F ₅ SO ₂ ) ₂ NLi), and the like. A solute may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the solute dissolved in the nonaqueous 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 a cyclic carbonate ester, a chain carbonate ester, and a cyclic carboxylate ester. Examples of the cyclic carbonate include propylene carbonate (PC) and ethylene carbonate (EC). Examples of the chain carbonate 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). A non-aqueous solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

Moreover, it is preferable to contain vinylene carbonate (VC) in the nonaqueous solvent from the viewpoint of further improving battery characteristics.

The content when vinylene carbonate (VC) is contained is preferably 0.1% by mass to 2% by mass, and more preferably 0.2% by mass to 1.5% by mass with respect to the total amount of the nonaqueous solvent.

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

The laminate type lithium ion secondary battery can be manufactured, for example, as follows. First, the positive electrode and the negative electrode are cut into squares, and tabs are welded to the respective electrodes to produce a positive electrode terminal and a negative electrode terminal. An electrode laminate is produced by laminating a separator between a positive electrode and a negative electrode, and accommodated in an aluminum laminate pack in that state, and the positive electrode terminal and the negative electrode terminal are taken out of the aluminum laminate pack and sealed. Next, an electrolytic solution is poured into the aluminum laminate pack, and the opening of the aluminum laminate pack is sealed. Thereby, a lithium ion secondary battery is obtained.

Next, an embodiment in which the present disclosure is applied to an 18650 type cylindrical 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, a lithium ion secondary battery 1 of the present disclosure has a bottomed cylindrical battery container 6 made of nickel-plated steel. The battery case 6 accommodates an electrode group 5 in which a strip-like positive electrode plate 2 and a negative electrode plate 3 are wound in a spiral shape with a separator 4 interposed therebetween. For example, the separator 4 has a width of 58 mm and a thickness of 30 μm. A ribbon-like positive electrode tab terminal made of aluminum and having one end fixed to the positive electrode plate 2 is led out on the upper end surface of the electrode group 5. The other end of the positive electrode tab terminal is joined by ultrasonic welding to the lower surface of a disk-shaped battery lid that is disposed on the upper side of the electrode group 5 and serves as a positive electrode external terminal. On the other hand, a ribbon-like negative electrode tab terminal made of copper with one end fixed to the negative electrode plate 3 is led out on the lower end surface of the electrode group 5. 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 the opposite sides of the both end faces of the electrode group 5, respectively. In addition, the insulation coating which abbreviate | omitted illustration is given to the outer peripheral surface whole periphery of the electrode group 5. FIG. The battery lid is caulked and fixed to the upper part of the battery container 6 via an insulating resin gasket. For this reason, the inside of the lithium ion secondary battery 1 is sealed. In addition, an electrolyte solution (not shown) is injected into the battery container 6.

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

[Example 1]
Into a 1 liter separable flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe, charged with 400 g of purified water and up to 74 ° C. with stirring under a nitrogen gas flow rate of 200 mL / min. After raising the temperature, the nitrogen gas flow was stopped. Next, an aqueous solution obtained by dissolving 0.347 g of a polymerization initiator ammonium persulfate in 2.5 g of purified water was added, and immediately, 40.0 g of a nitrile group-containing monomer acrylonitrile (manufactured by Wako Pure Chemical Industries, Ltd.), a formula ( II) 0.5 g of a cross-linking agent represented by triethylene glycol diacrylate (trade name: FA-232A, manufactured by Hitachi Chemical Co., Ltd.), 2.1 g of carboxy group-containing monomer, and formula (III) A mixture of 0.9 g of methoxytriethylene glycol acrylate (trade name: NK ester AM-30G, manufactured by Shin-Nakamura Chemical Co., Ltd.) represented by the following formula is maintained, and the temperature of the reaction system is maintained at 74 ± 2 ° C. However, it was dripped over 2 hours. Subsequently, an aqueous solution in which 0.42 g of ammonium persulfate was dissolved in 3.1 g of purified water was added to the suspended reaction system, and the temperature of the reaction system was maintained at 74 ± 2 ° C. for another 2 hours. Thereafter, the temperature of the reaction system was raised to 90 ± 5 ° C., an aqueous solution in which 0.21 g of ammonium persulfate was dissolved in 1.5 g of purified water was added, and the mixture was held at the same temperature for 2 hours. Then, after cooling to 40 ° C. over 1 hour, stirring was stopped and the mixture was allowed to stand overnight at room temperature (25 ° C.) to obtain a reaction solution in which a resin having a structural unit derived from a nitrile group-containing monomer was precipitated. . The reaction solution was filtered by suction, and the collected wet precipitate was washed 4 times with 500 g of purified water and then dried at 100 ° C. for 8 hours to obtain a resin A having a structural unit derived from a nitrile group-containing monomer. Obtained. Table 1 shows the composition of the monomer and the crosslinking agent.

[Example 2]
Into a 1 liter separable flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe, charged with 400 g of purified water and up to 74 ° C. with stirring under a nitrogen gas flow rate of 200 mL / min. After raising the temperature, the nitrogen gas flow was stopped. Next, an aqueous solution obtained by dissolving 0.347 g of a polymerization initiator ammonium persulfate in 2.5 g of purified water was added, and immediately, 40.0 g of a nitrile group-containing monomer acrylonitrile (manufactured by Wako Pure Chemical Industries, Ltd.), a formula ( II) 0.5 g of a cross-linking agent represented by triethylene glycol diacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-232A) and a carboxy group-containing monomer of 2.1 g of acrylic acid, The reaction system was added dropwise over 2 hours while maintaining the temperature of the reaction system at 74 ± 2 ° C. Subsequently, an aqueous solution in which 0.42 g of ammonium persulfate was dissolved in 3.1 g of purified water was added to the suspended reaction system, and the temperature of the reaction system was maintained at 74 ± 2 ° C. for another 2 hours. Thereafter, the temperature of the reaction system was raised to 90 ± 5 ° C., an aqueous solution in which 0.21 g of ammonium persulfate was dissolved in 1.5 g of purified water was added, and the mixture was held at the same temperature for 2 hours. Then, after cooling to 40 ° C. over 1 hour, stirring was stopped and the mixture was allowed to stand overnight at room temperature (25 ° C.) to obtain a reaction solution in which a resin having a structural unit derived from a nitrile group-containing monomer was precipitated. . The reaction solution was filtered by suction, and the collected wet precipitate was washed 4 times with 500 g of purified water and then dried at 100 ° C. for 8 hours to obtain a resin B having a structural unit derived from a nitrile group-containing monomer. Obtained. Table 1 shows the composition of the monomer and the crosslinking agent.

[Example 3]
Resin in the same manner as in Example 1, except that the amount of the monomer represented by the formula (II), triethylene glycol diacrylate (trade name: FA-232A, manufactured by Hitachi Chemical Co., Ltd.) was 0.05 g C was obtained. Table 1 shows the composition of the monomer and the crosslinking agent.

[Example 4]
Resin D was obtained in the same manner as in Example 1 except that the amount of acrylic acid used as the carboxy group-containing monomer was changed to 0.1 g. Table 1 shows the composition of the monomer and the crosslinking agent.

[Comparative Example 1]
Example except that the amount of the methoxytriethylene glycol acrylate as the monomer represented by the formula (III) was changed to 1.4 g without using the triethylene glycol diacrylate as the crosslinking agent represented by the formula (II). In the same manner as in Example 1, Resin E was obtained. Table 1 shows the composition of the monomer and the crosslinking agent.

[Example 5]
(1) Preparation of binder resin composition In a 500 mL separable flask equipped with a stirrer, a thermometer, and a cooling tube, 13.5 g of the resin A obtained in Example 1 was charged, and while stirring, N -212 g of methyl-2-pyrrolidone (organic solvent, Wako Pure Chemical Industries, Ltd., special grade) was added and stirred at 100 ± 5 ° C. for 5 hours. After confirming dissolution of the resin, it was cooled to 40 ° C. over 1 hour to obtain a binder resin composition A (N-methyl-2-pyrrolidone solution containing resin A).

(2) Production of Rollability Evaluation Sample Lithium Manganese Cobaltate (Positive Electrode Active Material, LiNi _1/3 Mn _1/3 Co _1/3 O ₂ (Ni: Mn: Co (Molar Ratio) = 1: 1: 1) ), Average particle size: 6.5 μm), acetylene black (conductive agent, trade name: HS-100, average particle size 48 nm (Denka Co., Ltd. catalog value), manufactured by Denka Co., Ltd.), and binder resin composition A, N-methyl-2-pyrrolidone (organic solvent, Wako Pure Chemical Industries, Ltd.) was mixed so that the mass ratio of the solid content was positive electrode active material: conductive agent: resin A = 94.0: 4.5: 1.5. It was sufficiently dispersed in a special grade), and a positive electrode mixture paste was prepared. This positive electrode mixture paste was applied to one side of a 15 μm-thick aluminum foil (positive electrode current collector, Mitsubishi Aluminum Co., Ltd.) so that the coating amount was 150 ± 1 g / m ² and dried at 100 ° C. for 30 minutes. . Furthermore, it dried for 12 hours with the vacuum dryer set to 120 degreeC, and obtained the sample A for rollability evaluation.

(3) Rollability evaluation Sample A for rollability evaluation was cut into strips having a width of 53 mm, and the electrode thickness after being pressed once at a pressure of 70 kN / 53 mm using a roll press at room temperature was measured. The electrode thickness was measured at a total of 10 locations within the same electrode using a micrometer (manufactured by Mitutoyo Corporation), and the average value was adopted. The mixture density was calculated from the electrode thickness, and the higher the density, the better the rollability. The results are shown in Table 2.

(4) Adhesive evaluation Amorphous carbon having an average particle diameter of 20 μm and the binder resin composition A obtained in Example 1 were 99.0% by mass in terms of solid content of amorphous carbon and resin A. Was mixed at a ratio of 1.0% by mass, and N-methyl-2-pyrrolidone was further added to adjust the viscosity to prepare a slurry. The slurry was applied to a copper foil (current collector) having a thickness of 10 μm, and then dried for 1 hour with a blow-type dryer set at 80 ° C. to produce a sheet-like electrode. This was pressed with a roll press to produce an electrode having an electrode mixture layer density of 1.5 g / cm ³ . At this time, the presence or absence of peeling of the electrode mixture layer was visually confirmed. The results are shown in Table 2.

(5) Swelling resistance to electrolytic solution Resin A and N-methyl-2-pyrrolidone (organic solvent, manufactured by Wako Pure Chemical Industries, Ltd., special grade) are mixed and contain 6% by mass of resin A based on the whole. A slurry was prepared. This slurry was applied on a glass substrate so that the film thickness after drying was about 10 μm, dried for 2 hours with a 120 ° C. blow-type dryer, and then dried for 10 hours with a vacuum dryer (120 ° C./1 torr). Thus, a resin film was prepared. The obtained resin film was cut into 2 cm square in a glove box in an argon atmosphere, and the mass was measured. Thereafter, the cut resin film and a sufficient amount of electrolyte to immerse the resin film in a sealable container (ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 mixed solution containing 1M LiPF ₆₎ (Volume ratio)) was added and sealed. The sealed container containing the resin film and the electrolytic solution was placed in a constant temperature bath at 25 ° C. and allowed to stand for 24 hours. The sealed container was again put in a glove box in an argon atmosphere, the resin film was taken out, the electrolyte solution on the surface was wiped off with filter paper, and the mass after immersion was measured. The degree of swelling was calculated from the following formula. It was judged that the lower the degree of swelling, the better the swelling resistance. The results are shown in Table 2.
Swelling degree (%) = (mass after immersion (g) −mass before immersion (g)) / (mass before immersion (g) × 100

[Examples 6 to 8 and Comparative Example 2]
The method shown in Example 1 except that Resin B (Example 6), Resin C (Example 7), Resin D (Example 8) and Resin E (Comparative Example 1) were used instead of Resin A. Evaluation was performed. The results are shown in Table 2.

As is clear from Table 2, in Examples 5 to 8 using the resins A to D obtained in Examples 1 to 4, it was found that the film thickness after pressing was small and the density after pressing was high. When methoxytriethylene glycol acrylate was used in combination (Examples 5, 7 and 8), the density after pressing tended to be particularly high. On the other hand, when triethylene glycol diacrylate was not used (Comparative Example 2), the film thickness after pressing was large and the density after pressing was low. From this, it can be seen that the resins A to D containing the structural unit derived from the specific cross-linking agent are excellent in rollability.

All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

Claims (22)

1. A structural unit derived from a nitrile group-containing monomer;
   A structural unit derived from a crosslinking agent containing at least two groups containing an ethylenically unsaturated double bond in one molecule;
   Resin for energy device electrode containing.
2. The resin for an energy device electrode according to claim 1, wherein the group containing an ethylenically unsaturated double bond is at least one selected from the group consisting of an acryloyl group and a methacryloyl group.
3. The resin for energy device electrodes according to claim 1 or 2, wherein the crosslinking agent contains a compound represented by the following formula (I).
   

   

   
   [In Formula (I), R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, R ₃ represents an alkylene group, and n represents an integer of 1 to 50. ]
4. The resin for energy device electrodes according to claim 3, wherein the compound represented by the formula (I) includes a compound represented by the following formula (II).
   

   

   
   [In Formula (II), R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. ]
5. The resin for energy device electrodes according to claim 4, wherein the compound represented by the formula (II) contains triethylene glycol diacrylate.
6. The ratio of the structural unit derived from the crosslinking agent to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.0001 mol to 0.02 mol. Resin for energy device electrodes.
7. The resin for an energy device electrode according to any one of claims 1 to 6, further comprising a structural unit derived from a carboxy group-containing monomer and containing a carboxy group.
8. The resin for energy device electrodes according to claim 7, wherein the carboxy group-containing monomer contains acrylic acid.
9. The ratio of the structural unit derived from the carboxy group-containing monomer and containing a carboxy group to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol. The resin for energy device electrodes according to claim 8.
10. The energy device electrode resin according to any one of claims 1 to 9, wherein the nitrile group-containing monomer contains acrylonitrile.
11. The resin for an energy device electrode according to any one of claims 1 to 10, further comprising a structural unit derived from a monomer represented by the following formula (III).
    

    

    
    [In the formula (III), R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom or a monovalent hydrocarbon group, and m represents an integer of 1 to 50. ]
12. The resin for energy device electrodes according to claim 11, wherein R ₅ in the monomer represented by the formula (III) is an alkyl group or a phenyl group.
13. The resin for energy device electrodes according to claim 11, wherein the monomer represented by the formula (III) contains methoxytriethylene glycol acrylate.
14. The ratio of the structural unit derived from the monomer represented by the formula (III) to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol. Item 14. The energy device electrode resin according to any one of Items 13 to 13.
15. The resin for an energy device electrode according to any one of claims 1 to 14, further comprising a structural unit derived from a monomer represented by the following formula (IV).
    

    

    
    [In the formula (IV), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an alkyl group having 4 to 100 carbon atoms. ]
16. The ratio of the structural unit derived from the monomer represented by the formula (IV) to 1 mol of the structural unit derived from the nitrile group-containing monomer is 0.001 mol to 0.2 mol. Resin for energy device electrodes.
17. An energy device electrode forming composition comprising the energy device electrode resin according to any one of claims 1 to 16.
18. 18. The composition for forming an energy device electrode according to claim 17, further comprising a positive electrode active material containing a lithium-containing composite metal oxide having lithium and nickel and a proportion of nickel in the metal excluding lithium being 50 mol% or more. .
19. The composition for forming an energy device electrode according to claim 18, wherein the lithium-containing composite metal oxide contains a compound represented by the following formula (V).
    _{Li a Ni b Co c M d} O 2 + e Formula (V)
    [In Formula (V), M is at least one selected from the group consisting of Al, Mn, Mg and Ca, and a, b, c, d and e are 0.2 ≦ a ≦ 1. 2, 0.5 ≦ b ≦ 0.9, 0.1 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.2, −0.2 ≦ e ≦ 0.2 B + c + d = 1. ]
20. A current collector,
    An electrode mixture layer provided on at least one surface of the current collector and formed from the composition for forming an energy device electrode according to any one of claims 17 to 19,
    Having energy device electrode.
21. An energy device comprising the energy device electrode according to claim 20.
22. The energy device according to claim 21, which is a lithium ion secondary battery.

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