WO2018168502A1

WO2018168502A1 - Binder composition for nonaqueous secondary battery electrode, conductive-material paste composition for nonaqueous secondary battery electrode, slurry composition for nonaqueous secondary battery electrode, electrode for nonaqueous secondary battery, and nonaqueous secondary battery

Info

Publication number: WO2018168502A1
Application number: PCT/JP2018/007841
Authority: WO
Inventors: 慎介菅原; 卓松村
Original assignee: 日本ゼオン株式会社
Priority date: 2017-03-13
Filing date: 2018-03-01
Publication date: 2018-09-20
Also published as: JPWO2018168502A1; KR20190122690A; KR102569975B1; JP7031655B2

Abstract

The purpose of the present invention is to provide a binder composition for a nonaqueous secondary battery electrode having excellent viscosity stability and the ability to form an electrode mix layer for which swelling in an electrolyte solution is reduced. This binder composition contains a polymer having a functional group capable of binding with a cationic group and an organic compound having 2 or more cationic groups and a molecular weight of 8,000 or less.

Description

Non-aqueous secondary battery electrode binder composition, non-aqueous secondary battery electrode conductive material paste composition, non-aqueous secondary battery electrode slurry composition, non-aqueous secondary battery electrode and non-aqueous secondary battery

The present invention relates to a binder composition for a non-aqueous secondary battery electrode, a conductive material paste composition for a non-aqueous secondary battery electrode, a slurry composition for a non-aqueous secondary battery electrode, an electrode for a non-aqueous secondary battery, and a non-aqueous secondary battery. The present invention relates to a secondary battery.

Non-aqueous secondary batteries such as lithium ion secondary batteries (hereinafter sometimes simply referred to as “secondary batteries”) have the characteristics of being small and light, having high energy density, and capable of repeated charge and discharge. Yes, it is used for a wide range of purposes. Therefore, in recent years, improvement of battery members such as electrodes has been studied for the purpose of further improving the performance of non-aqueous secondary batteries.

Here, an electrode used in a secondary battery such as a lithium ion secondary battery is usually a current collector and an electrode mixture layer (a positive electrode mixture layer or a negative electrode mixture layer) formed on the current collector. It has. And this electrode compound material layer apply | coats the slurry composition containing an electrode active material, the binder composition containing a binder, etc. on a collector, for example, and dries the apply | coated slurry composition. It is formed.

Thus, in recent years, attempts have been made to improve the binder composition used for forming the electrode mixture layer in order to achieve further improvement in the performance of the secondary battery.
Specifically, for example, in Patent Document 1, a non-crosslinked polymer having a functional group capable of binding to a polyvalent metal ion, a polyvalent metal compound containing a polyvalent metal and a ligand having a molecular weight of 30 or more, and an organic The binder composition containing the solvent is excellent in viscosity stability, and by using this binder composition, the adhesion between the electrode mixture layer and the current collector is improved, and the cycle characteristics of the secondary battery are improved. It has been reported that it can be improved.

JP 2008-166058 A

However, it cannot be said that the viscosity stability of the conventional binder composition is sufficiently satisfactory. Moreover, the electrode mixture layer obtained by using the conventional binder composition is excessively swollen in the electrolytic solution. And in the electrode provided with the electrode compound-material layer obtained from such a binder composition, it was difficult to exhibit the cycling characteristics excellent in the secondary battery. That is, the conventional binder composition is improved in terms of sufficiently enhancing the cycle characteristics of the secondary battery by suppressing the swelling of the electrode mixture layer in the electrolyte while ensuring the viscosity stability. There was room for.

Then, this invention aims at providing the binder composition for non-aqueous secondary battery electrodes which can form the electrode compound-material layer which was excellent in viscosity stability, and the swelling in electrolyte solution was suppressed. .
In addition, the present invention provides a non-aqueous secondary battery capable of forming an electrode mixture layer in which swelling in an electrolyte is suppressed and capable of exhibiting excellent cycle characteristics in a non-aqueous secondary battery It aims at providing the electrically conductive material paste composition for electrodes, and the slurry composition for non-aqueous secondary battery electrodes.
Furthermore, the present invention provides an electrode for a non-aqueous secondary battery that includes an electrode mixture layer in which swelling in an electrolytic solution is suppressed and that can exhibit excellent cycle characteristics in a non-aqueous secondary battery. The purpose is to provide.
And an object of this invention is to provide the non-aqueous secondary battery which has the outstanding cycling characteristics.

The present inventor has intensively studied for the purpose of solving the above problems. And this inventor is the binder composition containing the polymer which has a functional group which can couple | bond with a cationic group, and the organic compound which has two or more cationic groups, and molecular weight is below a predetermined value However, it was found that if the binder composition was excellent in viscosity stability and the swelling in the electrolytic solution was suppressed, an electrode mixture layer with reduced swelling could be formed, and the present invention was completed.

That is, the present invention aims to advantageously solve the above-mentioned problems, and the binder composition for a non-aqueous secondary battery electrode according to the present invention is a polymer having a functional group capable of binding to a cationic group. And an organic compound having two or more cationic groups and having a molecular weight of 8,000 or less. Thus, a binder composition containing a polymer having a functional group capable of binding to a cationic group and an organic compound having two or more cationic groups and having a molecular weight of a predetermined value or less has a viscosity. If it is excellent in stability and the said binder composition is used, the electrode compound-material layer by which the swelling in electrolyte solution was suppressed can be formed.
In the present invention, the “cationic group” refers to a functional group that can be cationic by being present alone or together with a substance that supplies a positive charge in a solvent. In the present invention, “functional group capable of binding to a cationic group” refers to a functional group capable of interacting with a cationic group in a solvent by an ionic bond, a hydrogen bond, a covalent bond, or the like.

Here, in the binder composition for a non-aqueous secondary battery electrode of the present invention, the functional group capable of binding to the cationic group is selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a hydroxyl group. It is preferable that it is at least one kind. If the polymer which has the predetermined functional group mentioned above is used, the swelling in the electrolyte solution of an electrode compound-material layer can be further suppressed, ensuring the viscosity stability of a binder composition fully.

In the binder composition for a non-aqueous secondary battery electrode of the present invention, the polymer has a monomer unit containing a functional group capable of binding to a cationic group in an amount of 0.1% by mass to 20% by mass. It is preferable to include by a ratio. If a polymer containing a monomer unit containing a functional group capable of binding to a cationic group in an amount within the above range is used, the electrode mixture layer is sufficiently secured while ensuring the viscosity stability of the binder composition. The swelling in the electrolyte can be further suppressed.
In the present invention, “including a monomer unit” means “a repeating unit derived from a monomer is contained in a polymer obtained using the monomer”. The proportion of each monomer unit and / or structural unit in the polymer can be measured using a nuclear magnetic resonance (NMR) method such as ¹ H-NMR and ¹³ C-NMR.

Furthermore, the binder composition for a non-aqueous secondary battery electrode of the present invention preferably contains 0.1 to 20 parts by mass of the organic compound per 100 parts by mass of the polymer. If the blending amount of the organic compound is within the above range, swelling of the electrode mixture layer in the electrolytic solution can be further suppressed while sufficiently ensuring the viscosity stability of the binder composition.

Here, in the binder composition for a non-aqueous secondary battery electrode according to the present invention, the polymer includes a nitrile group-containing monomer unit, and at least one of a conjugated diene monomer unit and an alkylene structural unit, The proportion of the nitrile group-containing monomer unit in the polymer is 5% by mass or more and 35% by mass or less, and the total of the proportion of the conjugated diene monomer unit and the proportion of the alkylene structural unit in the polymer is 30 mass% or more and 90 mass% or less is preferable. The above-described polymer can be dissolved well in the solvent of the binder composition, and can be adsorbed well to the conductive material and can be dispersed well (that is, excellent dispersibility in the conductive material). And by using the said polymer, the swelling in the electrolyte solution of an electrode compound-material layer can further be suppressed, ensuring the viscosity stability of a binder composition fully.

Moreover, this invention aims at solving the said subject advantageously, The electrically conductive material paste composition for non-aqueous secondary battery electrodes of this invention is a conductive material and any one of the non-aqueous systems described above. And a binder composition for a secondary battery electrode. If a conductive material paste composition containing a conductive material and any of the binder compositions described above is prepared, and an electrode active material is added to the conductive material paste composition to prepare a slurry composition, an electrolytic solution It is possible to form an electrode mixture layer in which swelling in the inside is suppressed, and to exhibit excellent cycle characteristics in the secondary battery.

Moreover, this invention aims at solving the said subject advantageously, The slurry composition for non-aqueous secondary battery electrodes of this invention is an electrode active material and any one of the non-aqueous secondary batteries described above. It contains the binder composition for secondary battery electrodes, or the electrically conductive material paste for non-aqueous secondary battery electrodes mentioned above. Thus, by using a slurry composition containing an electrode active material and any of the binder composition or conductive material paste described above, an electrode mixture layer in which swelling in the electrolyte is suppressed can be formed. The secondary battery can exhibit excellent cycle characteristics.

Moreover, this invention aims at solving the said subject advantageously, The electrode for non-aqueous secondary batteries of this invention is formed using the slurry composition for non-aqueous secondary battery electrodes mentioned above. It is characterized by comprising the electrode mixture layer. Thus, the electrode mixture layer obtained using the slurry composition described above is suppressed from swelling in the electrolytic solution, and the electrode including this electrode mixture layer has excellent cycle characteristics for secondary batteries. It can be demonstrated.

Moreover, this invention aims at solving the said subject advantageously, The non-aqueous secondary battery of this invention is equipped with a positive electrode, a negative electrode, electrolyte solution, and a separator, At least one of the said positive electrode and negative electrode Is the electrode for a non-aqueous secondary battery described above. Thus, the non-aqueous secondary battery including the above-described electrode has excellent cycle characteristics.

ADVANTAGE OF THE INVENTION According to this invention, the binder composition for non-aqueous secondary battery electrodes which is excellent in viscosity stability and can form the electrode compound-material layer by which the swelling in electrolyte solution was suppressed is obtained.
In addition, according to the present invention, a non-aqueous secondary layer that can form an electrode mixture layer in which swelling in the electrolytic solution is suppressed and that can exhibit excellent cycle characteristics in a non-aqueous secondary battery can be formed. A conductive material paste composition for a secondary battery electrode and a slurry composition for a non-aqueous secondary battery electrode are obtained.
Furthermore, according to the present invention, the non-aqueous secondary battery is provided with an electrode mixture layer in which swelling in the electrolytic solution is suppressed and can exhibit excellent cycle characteristics in the non-aqueous secondary battery. An electrode is obtained.
And according to this invention, the non-aqueous secondary battery which has the outstanding cycling characteristics is obtained.

Hereinafter, embodiments of the present invention will be described in detail.
Here, the binder composition for non-aqueous secondary battery electrodes of the present invention can be used when preparing a slurry composition for non-aqueous secondary battery electrodes. Moreover, the binder composition for non-aqueous secondary battery electrodes of the present invention is mixed with a conductive material, and contains a non-aqueous secondary battery electrode binder composition and a conductive material. It can use for preparation of the slurry composition for non-aqueous secondary battery electrodes, after making it into a composition. And the slurry composition for non-aqueous secondary battery electrodes prepared using the binder composition for non-aqueous secondary battery electrodes of the present invention is used for forming electrodes of non-aqueous secondary batteries such as lithium ion secondary batteries. Can be used. Furthermore, the non-aqueous secondary battery of the present invention is characterized by using a non-aqueous secondary battery electrode formed using the slurry composition for a non-aqueous secondary battery electrode of the present invention.
The binder composition for non-aqueous secondary battery electrodes, the conductive material paste composition for non-aqueous secondary battery electrodes, and the slurry composition for non-aqueous secondary battery electrodes of the present invention form the positive electrode of the non-aqueous secondary battery. In particular, it can be suitably used.

(Binder composition for non-aqueous secondary battery electrode)
The binder composition for a non-aqueous secondary battery electrode of the present invention has a polymer having a functional group capable of binding to a cationic group (hereinafter sometimes referred to as “polymer (A)”) and two or more. An organic compound having a cationic group (hereinafter, sometimes referred to as “polyvalent cationic organic compound (B)”), and optionally further containing other components that can be blended in the electrode of the secondary battery. contains. Here, in the binder composition for nonaqueous secondary battery electrodes of the present invention, the above-described polyvalent cationic organic compound (B) has a molecular weight of 8000 or less. Moreover, the binder composition for nonaqueous secondary battery electrodes of the present invention usually further contains a solvent such as an organic solvent.

And since the binder composition of this invention contains the polymer which has a functional group which can couple | bond with a cationic group, and the polyvalent cationic organic compound (B) whose molecular weight is 8000 or less, it preserve | saved for a long time. Even if it is a case, a viscosity change is small and the swelling in the electrolyte solution of an electrode compound-material layer can be suppressed.
The reason why the binder composition of the present invention is excellent in viscosity stability and can suppress swelling of the electrode mixture layer in the electrolytic solution is not clear, but is presumed to be as follows.
That is, the binder composition of the present invention allows the functional group in the polymer (A) and the cationic group in the polyvalent cationic organic compound (B) to interact well in a solvent. Compared with the case where the coalesced (A) and the polyvalent metal compound containing the predetermined ligand described in Patent Document 1 are used in combination, the viscosity change with time is suppressed. Further, since the binder composition of the present invention contains the polymer (A) and the polyvalent cationic organic compound (B), the slurry composition containing the binder composition is dried and the electrode mixture layer. Is formed, the functional group in the polymer (A) and the cationic group in the polyvalent cationic organic compound (B) interact more strongly due to crosslinking or the like. By this strong interaction, a rigid network is formed, and the electrode mixture layer does not swell excessively in the electrolytic solution. Moreover, since the molecular weight of the above-described polyvalent cationic organic compound (B) is 8000 or less, the polyvalent cationic organic compound (B) does not excessively thicken the binder composition, and Viscosity change with time is further suppressed.
Therefore, according to the present invention, while ensuring the viscosity stability of the binder composition, swelling of the electrode mixture layer in the electrolytic solution can be suppressed, and excellent cycle characteristics can be exhibited in the secondary battery. .

<Polymer (A)>
The polymer (A) is an electrode produced by forming an electrode mixture layer on a current collector using a slurry composition for a nonaqueous secondary battery electrode prepared using a binder composition. It keeps so that the component contained in a material layer may not detach | leave from an electrode compound-material layer (namely, it is an adhesive polymer which functions as a binder).

<< Functional group capable of binding to cationic group >>
The functional group capable of binding to the cationic group of the polymer (A) (hereinafter sometimes referred to as “binding functional group”) is not particularly limited, but can interact well with the cationic group. Examples include carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, and hydroxyl groups. Among these, a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group are more preferable, and a carboxylic acid group is particularly preferable. When the polymer (A) having these functional groups is used, the viscosity of the binder composition is sufficiently ensured, and the swelling of the electrode mixture layer in the electrolytic solution is further suppressed. The cycle characteristics can be further improved. The polymer (A) may have only one type of binding functional group or may have two or more types.

<< Composition of Polymer (A) >>
Here, the method for introducing the binding functional group into the polymer (A) is not particularly limited, and the polymer using the monomer (binding functional group-containing monomer) containing the binding functional group described above. The polymer (A) containing a binding functional group-containing monomer unit may be obtained, or any polymer having a terminal binding functional group may be obtained by, for example, end-modifying any polymer. The union (A) may be obtained, but the former is preferred. The polymer (A) containing a binding functional group-containing monomer unit may contain a repeating unit other than the binding functional group-containing monomer unit.

[Binding functional group-containing monomer unit]
Here, as the binding functional group-containing monomer capable of forming the binding functional group-containing monomer unit, preferably, a monomer having a carboxylic acid group, a monomer having a sulfonic acid group, phosphorous Examples include monomers having an acid group and monomers having a hydroxyl group.

Examples of the monomer having a carboxylic acid group include monocarboxylic acids and derivatives thereof, dicarboxylic acids and acid anhydrides, and derivatives thereof.
Examples of monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid.
Examples of monocarboxylic acid derivatives include 2-ethylacrylic acid, isocrotonic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, β-diaminoacrylic acid, and the like. Can be mentioned.
Examples of the dicarboxylic acid include maleic acid, fumaric acid, itaconic acid and the like.
Dicarboxylic acid derivatives include methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, monobutyl maleate, monononyl maleate, monodecyl maleate, monododecyl maleate, maleic acid And maleic acid monoesters such as monooctadecyl and monofluoroalkyl maleate.
Examples of the acid anhydride of dicarboxylic acid include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
Moreover, as a monomer which has a carboxylic acid group, the acid anhydride which produces | generates a carboxyl group by hydrolysis can also be used.

Examples of the monomer having a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, and 2-acrylamido-2-methylpropane. Examples thereof include sulfonic acid.
In the present invention, “(meth) allyl” means allyl and / or methallyl.

Furthermore, examples of the monomer having a phosphoric acid group include phosphoric acid-2- (meth) acryloyloxyethyl phosphate, methyl-2- (meth) acryloyloxyethyl phosphate, and ethyl phosphate- (meth) acryloyloxyethyl phosphate. Etc.
In the present invention, “(meth) acryloyl” means acryloyl and / or methacryloyl.

Examples of the monomer having a hydroxyl group include ethylenically unsaturated alcohols such as (meth) allyl alcohol, 3-buten-1-ol, 5-hexen-1-ol; 2-hydroxyethyl acrylate, acrylic 2-hydroxypropyl acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate, di-2-hydroxypropyl itaconate, etc. An alkanol ester of an ethylenically unsaturated carboxylic acid of the general formula: CH ₂ ═CR ^Z —COO— (C _n H _2n O) _m —H (wherein m is an integer of 2 to 9, and n is 2 to 4) integer, R ^Z of the esters of a polyalkylene glycol and (meth) acrylic acid represented by hydrogen or a methyl group) Mono (meth) acrylic acid esters of dihydroxy esters of dicarboxylic acids such as 2-hydroxyethyl-2 ′-(meth) acryloyloxyphthalate and 2-hydroxyethyl-2 ′-(meth) acryloyloxysuccinate; Vinyl ethers such as hydroxyethyl vinyl ether and 2-hydroxypropyl vinyl ether; (meth) allyl-2-hydroxyethyl ether, (meth) allyl-2-hydroxypropyl ether, (meth) allyl-3-hydroxypropyl ether, (meth) Mono (me) of alkylene glycol such as allyl-2-hydroxybutyl ether, (meth) allyl-3-hydroxybutyl ether, (meth) allyl-4-hydroxybutyl ether, (meth) allyl-6-hydroxyhexyl ether ) Allyl ethers; polyoxyalkylene glycol mono (meth) allyl ethers such as diethylene glycol mono (meth) allyl ether and dipropylene glycol mono (meth) allyl ether; glycerin mono (meth) allyl ether, (meth) allyl-2 -Mono (meth) allyl ethers of halogen and hydroxy-substituted products of (poly) alkylene glycol, such as chloro-3-hydroxypropyl ether, (meth) allyl-2-hydroxy-3-chloropropyl ether; eugenol, isoeugenol, etc. (Meth) allyl-2-hydroxyethyl thioether, (meth) allyl-2-hydroxypropyl thioether, and other alkylene glycols (Meth) allyl thioethers; and the like.
In the present invention, “(meth) acryl” means acryl and / or methacryl.

Among these, the polymer (A) interacts well with the polyvalent cationic organic compound (B), and the viscosity of the binder composition is sufficiently ensured to swell in the electrolyte solution while ensuring sufficient viscosity stability. From the viewpoint of further improving the cycle characteristics of the secondary battery, as the binding functional group-containing monomer, a monomer having a carboxylic acid group, a monomer having a sulfonic acid group, and A monomer having a phosphoric acid group is preferable, and a monomer having a carboxylic acid group is more preferable. That is, the binding functional group-containing monomer unit is selected from the group consisting of a monomer unit having a carboxylic acid group, a monomer unit having a sulfonic acid group, and a monomer unit having a phosphate group. At least one is preferable, and a monomer unit having a carboxylic acid group is more preferable.
Moreover, a binding functional group containing monomer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The proportion of the binding functional group-containing monomer unit contained in the polymer (A) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and 1% by mass. % Or more, more preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 6% by mass or less. If the ratio of the binding functional group-containing monomer unit contained in the polymer (A) is not more than the above upper limit value, the polymer (A) excessively interacts with the polyvalent cationic organic compound (B). Nor. Therefore, aggregation of these components can be suppressed to sufficiently ensure the viscosity stability of the binder composition, and the cycle characteristics of the secondary battery can be further improved. Moreover, if the ratio of the binding functional group-containing monomer unit contained in the polymer (A) is not less than the above lower limit value, the electrolyte solution of the electrode mixture layer while sufficiently ensuring the viscosity stability of the binder composition Swelling in the inside can be further suppressed, and the cycle characteristics of the secondary battery can be further improved.

[Repeating unit other than the binding functional group-containing monomer unit]
In addition, the repeating unit other than the binding functional group-containing monomer unit that can be contained in the polymer (A) is not particularly limited, and is a conjugated diene monomer unit, an alkylene structural unit, a nitrile group-containing single amount. Examples include body units, (meth) acrylic acid ester monomer units, and aromatic vinyl monomer units.

-Conjugated diene monomer unit-
Here, examples of the conjugated diene monomer that can form a conjugated diene monomer unit include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and the like. Examples thereof include conjugated diene compounds having 4 or more carbon atoms. Of these, 1,3-butadiene is preferred.
These can be used alone or in combination of two or more.

-Alkylene structural unit-
The alkylene structural unit is a repeating unit composed of only an alkylene structure represented by the general formula: —C _n H _2n — [where n is an integer of 2 or more].
Here, the alkylene structural unit may be linear or branched, but from the viewpoint of improving the dispersion stability of the slurry composition for a non-aqueous secondary battery electrode, the alkylene structural unit is a straight chain. It is preferably a chain, that is, a linear alkylene structural unit. From the viewpoint of further improving the dispersion stability of the slurry composition for non-aqueous secondary battery electrodes, the carbon number of the alkylene structural unit is 4 or more (that is, n in the above general formula is an integer of 4 or more). Is preferred.

The method for introducing the alkylene structural unit into the polymer (A) is not particularly limited. For example, the following method (1) or (2):
(1) Method of converting a conjugated diene monomer unit into an alkylene structural unit by preparing a copolymer from a monomer composition containing a conjugated diene monomer and hydrogenating the copolymer (2 And a method of preparing a copolymer from a monomer composition containing a 1-olefin monomer. Among these, the method (1) is preferable because the production of the polymer (A) is easy.

The conjugated diene monomer used in the above method (1) includes 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and the like having 4 or more carbon atoms. Examples thereof include conjugated diene compounds, among which 1,3-butadiene is preferable. That is, the alkylene structural unit is preferably a structural unit obtained by hydrogenating a conjugated diene monomer unit (conjugated diene hydride unit), and a structural unit obtained by hydrogenating a 1,3-butadiene unit (1 , 3-butadiene hydride unit). The selective hydrogenation of the conjugated diene monomer unit can be performed using a known method such as an oil layer hydrogenation method or an aqueous layer hydrogenation method.
Examples of the 1-olefin monomer used in the method (2) include ethylene, propylene, 1-butene, 1-hexene and the like.
These conjugated diene monomers and 1-olefin monomers can be used alone or in combination of two or more.

-Nitrile group-containing monomer unit-
Furthermore, examples of the nitrile group-containing monomer that can form a nitrile group-containing monomer unit include α, β-ethylenically unsaturated nitrile monomers. Specifically, the α, β-ethylenically unsaturated nitrile monomer is not particularly limited as long as it is an α, β-ethylenically unsaturated compound having a nitrile group. For example, acrylonitrile; α-chloroacrylonitrile, α-halogenoacrylonitrile such as α-bromoacrylonitrile; α-alkylacrylonitrile such as methacrylonitrile and α-ethylacrylonitrile; and the like. Among these, as the nitrile group-containing monomer, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable.
These can be used alone or in combination of two or more.

-(Meth) acrylate monomer units-
Examples of the (meth) acrylate monomer that can form a (meth) acrylate monomer unit include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, and t-butyl. Alkyl acrylates such as acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate Esters: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-buty Methacrylate, t-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, stearyl methacrylate Methacrylic acid alkyl esters such as; Among these, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate are preferable, and n-butyl acrylate, ethyl methacrylate, and 2-ethylhexyl acrylate are more preferable. preferable.
These can be used alone or in combination of two or more.

-Aromatic vinyl monomer unit-
Furthermore, examples of the aromatic vinyl monomer that can form an aromatic vinyl monomer unit include styrene, α-methylstyrene, butoxystyrene, and vinylnaphthalene. Of these, styrene is preferred.
These can be used alone or in combination of two or more.

Among the repeating units other than the above-mentioned binding functional group-containing monomer units, the solubility of the polymer (A) in the binder composition in the solvent and the dispersibility of the conductive material and the like are improved, and as a result, the binder composition From the viewpoint of further improving the cycle characteristics of the secondary battery by further suppressing the swelling of the electrode mixture layer in the electrolyte while sufficiently ensuring the viscosity stability of the polymer, the polymer (A) is a nitrile group. It preferably includes a monomer unit, and at least one of a conjugated diene monomer unit and an alkylene structural unit, and more preferably includes a nitrile group-containing monomer unit and an alkylene structural unit.

The ratio of the nitrile group-containing monomer unit contained in the polymer (A) is preferably 5% by mass or more, more preferably 7% by mass or more, and further preferably 9% by mass or more. Preferably, it is 10 mass% or more, It is especially preferable that it is 35 mass% or less, It is more preferable that it is 29 mass% or less, It is still more preferable that it is 23 mass% or less. If the ratio of the nitrile group-containing monomer unit contained in the polymer (A) is not more than the above upper limit value, the swelling of the electrode mixture layer in the electrolyte solution is further suppressed, and the cycle characteristics of the secondary battery are improved. It can be further increased. Moreover, if the ratio of the nitrile group-containing monomer unit contained in the polymer (A) is not less than the above lower limit, the solubility of the polymer (A) in the binder composition of the binder increases, Sufficient viscosity stability can be ensured.

Further, the total of the ratio of the conjugated diene monomer unit and the alkylene structural unit contained in the polymer (A) is preferably 30% by mass or more, more preferably 40% by mass or more, and 90% by mass. Or less, more preferably 75% by mass or less. If the total of the ratio of the conjugated diene monomer unit and the alkylene structural unit contained in the polymer (A) is not more than the above upper limit, the solubility of the binder composition of the polymer (A) in the solvent is impaired. In addition, the viscosity stability of the binder composition can be sufficiently ensured. Moreover, if the sum total of the ratio of the conjugated diene monomer unit and alkylene structural unit which a polymer (A) contains is more than the said lower limit, the dispersibility with respect to a polymer (A) electrically conductive material etc. will increase. And while ensuring the viscosity stability of a binder composition fully, the cycling characteristics of a secondary battery can be improved further.

The proportion of the repeating unit other than the binding functional group-containing monomer unit, the conjugated diene monomer unit, the alkylene structural unit, and the nitrile group-containing monomer unit contained in the polymer (A) is 0% by mass. It can be set to 60% by mass or less.

[Method for Preparing Polymer (A)]
Although the preparation method of the polymer (A) described above is not particularly limited, the polymer (A) is necessary after, for example, polymerizing a monomer composition containing the monomer described above to obtain a copolymer. Can be prepared by hydrogenating (hydrogenating) the copolymer obtained.

Here, the content ratio of each monomer in the monomer composition used for the preparation of the polymer (A) can be determined according to the content ratio of each repeating unit in the polymer (A).
The polymerization mode is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be used. As the polymerization reaction, any reaction such as ionic polymerization, radical polymerization, and living radical polymerization can be used.
Further, the hydrogenation method of the copolymer is not particularly limited, and is a general method using a catalyst (for example, see International Publication No. 2012/165120, International Publication No. 2013/088099 and JP2013-8485A). Can be used.

<Multivalent cationic organic compound (B)>
The polyvalent cationic organic compound (B) is not particularly limited as long as it is an organic compound having a plurality of cationic groups in one molecule. Examples of the cationic group include a substituted or unsubstituted amino group (—NH ₂ , —NHR ¹ , —NR ¹ R ² , —N ⁺ R ¹ R ² R ^3, wherein R ¹ to R ³ are optional ), A substituted or unsubstituted imino group (═NH, ═NR ^4, where R ⁴ represents an arbitrary substituent), a nitrogen-containing functional group such as an oxazoline group (an amide group) Except). Among these, the polyvalent cationic organic compound (B) interacts favorably with the polymer (A), and the electrode composition layer swells in the electrolyte while ensuring the viscosity stability of the binder composition. From the viewpoint of further improving the cycle characteristics of the secondary battery and further improving the secondary battery, the primary amino group (unsubstituted amino group, —NH ₂ ), secondary amino group (—NHR ¹ ), substituted or An unsubstituted imino group is preferred. In addition, the polyvalent cationic organic compound (B) may have only one type of cationic group, or may have two or more types of cationic groups.
In the present invention, when the polymer which is an organic compound having two or more cationic groups has a functional group capable of binding to the cationic group, the polymer is not a polymer (A) but a polyvalent one. It shall correspond to the cationic organic compound (B).

<Molecular weight of polyvalent cationic organic compound (B)>
Here, the molecular weight of the polyvalent cationic organic compound (B) (in the case where the polyvalent cationic organic compound (B) is a polymer, it indicates “number average molecular weight”) needs to be 8000 or less. Yes, preferably 2000 or less, more preferably 1800 or less, still more preferably 1600 or less, and particularly preferably 1500 or less. When the molecular weight of the polyvalent cationic organic compound (B) exceeds 8000, the binder composition is excessively thickened, and the viscosity stability cannot be sufficiently secured, and the cycle characteristics of the secondary battery are also deteriorated. On the other hand, the molecular weight of the polyvalent cationic organic compound (B) is 60 or more from the viewpoint of sufficiently suppressing the swelling of the electrode mixture layer in the electrolyte and further improving the cycle characteristics of the secondary battery. It is preferable that it is 100 or more.
In the present invention, when the polyvalent cationic organic compound (B) is a polymer, the number average molecular weight is obtained as a polystyrene-equivalent molecular weight measured by gel permeation chromatography (developing solvent: tetrahydrofuran). it can.

<Example of polyvalent cationic organic compound (B)>
As the polyvalent cationic organic compound (B), the non-polymeric polyvalent cationic organic compound (B) can be used as long as the molecular weight is within the above-mentioned range, or the polyvalent cationic compound is a polymer. The organic compound (B) can also be used.
Here, the non-polymeric polyvalent cationic organic compound (B) includes ethylenediamine, diethylenetriamine, triethylenetetramine, phenyldiamine, 4,4′-diaminodiphenyl ether, N, N′-bis (3-phenyl-). 2-propenylidene) -1,6-hexanediamine, bisanilines and the like.
Examples of the polyvalent cationic organic compound (B) that is a polymer include polyethyleneimine; polyethyleneimine derivatives such as poly N-hydroxylethyleneimine and carboxymethylated polyethyleneimine sodium salt; polypropyleneimine; polyN-2- Polypropyleneimine derivatives such as dihydropropylpropylenimine; polyallylamine; polyallylamine derivatives such as polydimethyldiallylammonium halide; aminoethylated acrylic polymers obtained by aminoethylation of acrylic acid polymers; having substituted or unsubstituted amino groups Examples thereof include cationized cellulose obtained by modifying a cellulose derivative (such as hydroxyethyl cellulose or carboxymethyl cellulose) with a cationizing agent.
These can be used alone or in combination of two or more. Among these, from the viewpoint of further improving the cycle characteristics of the secondary battery by further suppressing the swelling of the electrode mixture layer in the electrolyte while sufficiently ensuring the viscosity stability of the binder composition. More preferred are polyethyleneimine derivatives, N, N′-bis (3-phenyl-2-propenylidene) -1,6-hexanediamine, polyallylamine, and diethylenetriamine.

<Amount of polyvalent cationic organic compound (B)>
And the compounding quantity of the polyvalent cationic organic compound (B) whose molecular weight is in the above-mentioned range is preferably 0.1 parts by mass or more per 100 parts by mass of the polymer (A), and 0.2 parts by mass. More preferably, it is more preferably 0.5 parts by mass or more, particularly preferably 2 parts by mass or more, preferably 20 parts by mass or less, and preferably 10 parts by mass or less. More preferably, it is 6 parts by mass or less. When the amount of the polyvalent cationic organic compound (B) is excessive, the viscosity stability of the binder composition is decreased. However, when the blending amount of the polyvalent cationic organic compound (B) is 20 parts by mass or less, the viscosity stability of the binder composition can be sufficiently ensured. Moreover, if the compounding quantity of the polyvalent cationic organic compound (B) is 0.1 parts by mass or more, the polymer (A) and the polyvalent cationic organic compound (B) are more rigid in the electrode mixture layer. A network can be formed. Therefore, the swelling of the electrode mixture layer in the electrolytic solution can be further suppressed, and the cycle characteristics of the secondary battery can be further improved.

<Solvent>
As a solvent of the binder composition for non-aqueous secondary battery electrodes, an organic solvent is preferable. The organic solvent is not particularly limited, and for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, amyl alcohol Alcohols such as acetone, ketones such as methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; ethers such as diethyl ether, dioxane and tetrahydrofuran; N, N-dimethylformamide, N-methylpyrrolidone (NMP) Amide polar organic solvents such as; aromatic hydrocarbons such as toluene, xylene, chlorobenzene, orthodichlorobenzene, paradichlorobenzene; These may be used alone or in combination of two or more.
Especially, as a solvent, a polar organic solvent is preferable and NMP is more preferable.

<Other ingredients>
In addition to the above components, the binder composition for nonaqueous secondary battery electrodes of the present invention includes a binder (polyvinylidene fluoride, polyacrylonitrile, polyacrylate, etc.) other than the polymer (A), a reinforcing material, Components such as a leveling agent, a viscosity modifier, and an electrolytic solution additive may be included in the binder composition. These are not particularly limited as long as they do not affect the battery reaction, and known ones such as those described in International Publication No. 2012/115096 can be used. Moreover, these components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

<Swelling degree of electrolyte solution of film made of binder composition>
The degree of swelling of the electrolytic solution of the film obtained by drying the binder composition of the present invention containing the above-mentioned components is preferably less than 2000% by mass, more preferably less than 1000% by mass, and 800% by mass. % Is more preferable, and it is particularly preferable that it is less than 600% by mass. When the electrolyte solution swelling degree of the film made of the binder composition is less than 2000% by mass, the cycle characteristics of the secondary battery can be sufficiently enhanced. Moreover, the electrolyte solution swelling degree of the film which consists of a binder composition is 100 mass% or more normally.
In addition, the electrolyte solution swelling degree of the film which consists of a binder composition can be measured using the method as described in the Example of this specification.

(Slurry composition for non-aqueous secondary battery electrode)
The slurry composition for non-aqueous secondary battery electrodes of the present invention includes an electrode active material and the binder composition described above, and optionally further includes a conductive material and other components. That is, the slurry composition of the present invention contains an electrode active material, the polymer (A) described above, the polyvalent cationic organic compound (B) described above, and a solvent, and optionally, a conductive material, It further contains other components. And since the slurry composition of this invention contains the binder composition mentioned above, as for the electrode compound-material layer formed using the slurry composition of this invention, the swelling in electrolyte solution is suppressed, and The secondary battery can exhibit excellent cycle characteristics.

<Electrode active material>
Here, the electrode active material is a material that transfers electrons in the electrode of the non-aqueous secondary battery. For example, when the non-aqueous secondary battery is a lithium ion secondary battery, a material that can occlude and release lithium is usually used as the electrode active material.
In addition, although the case where the slurry composition for non-aqueous secondary battery electrodes is a slurry composition for lithium ion secondary battery electrodes is demonstrated as an example below, this invention is not limited to the following example.

Then, as the positive electrode active material for a lithium ion secondary battery is not particularly limited, lithium-containing cobalt oxide (LiCoO _2), lithium manganate (LiMn ₂ O _4), lithium-containing nickel oxides (LiNiO ₂ ), Co—Ni—Mn lithium-containing composite oxide (Li (Co ₂ Mn Ni) O ₂ ), Ni—Mn—Al lithium-containing composite oxide, Ni—Co—Al lithium-containing composite oxide, olivine type Lithium iron phosphate (LiFePO ₄ ), olivine lithium manganese phosphate (LiMnPO ₄ ), Li ₂ MnO ₃ —LiNiO ₂ solid solution, Li _{1 + x} Mn _2−x O ₄ (0 <X <2) excess spinel _{_{_{_{compound, Li [Ni 0.17 Li 0.2 Co}}}} 0.07 Mn 0.56] O 2, LiNi Known positive electrode active material such _.5 Mn _1.5 O ₄ and the like.
In addition, the compounding quantity and particle diameter of a positive electrode active material are not specifically limited, It can be made to be the same as that of the positive electrode active material used conventionally.

Also, examples of the negative electrode active material for the lithium ion secondary battery include a carbon-based negative electrode active material, a metal-based negative electrode active material, and a negative electrode active material obtained by combining these.

Here, the carbon-based negative electrode active material refers to an active material having carbon as a main skeleton capable of inserting lithium (also referred to as “dope”). Examples of the carbon-based negative electrode active material include carbonaceous materials and graphite. Quality materials.
Examples of the carbonaceous material include graphitizable carbon and non-graphitizable carbon having a structure close to an amorphous structure typified by glassy carbon.
Here, as the graphitizable carbon, for example, a carbon material using tar pitch obtained from petroleum or coal as a raw material can be mentioned. Specific examples include coke, mesocarbon microbeads (MCMB), mesophase pitch carbon fibers, pyrolytic vapor grown carbon fibers, and the like.
In addition, examples of the non-graphitizable carbon include a phenol resin fired body, polyacrylonitrile-based carbon fiber, pseudo-isotropic carbon, furfuryl alcohol resin fired body (PFA), and hard carbon.

Furthermore, examples of the graphite material include natural graphite and artificial graphite.
Here, as the artificial graphite, for example, artificial graphite obtained by heat-treating carbon containing graphitizable carbon mainly at 2800 ° C. or higher, graphitized MCMB heat-treated at 2000 ° C. or higher, and mesophase pitch-based carbon fiber at 2000 ° C. Examples thereof include graphitized mesophase pitch-based carbon fibers that have been heat-treated.

Further, the metal-based negative electrode active material is an active material containing a metal, and usually includes an element capable of inserting lithium in the structure, and the theoretical electric capacity per unit mass when lithium is inserted is 500 mAh / The active material which is more than g. Examples of the metal active material include lithium metal and a single metal capable of forming a lithium alloy (for example, Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, Si, Sn). , Sr, Zn, Ti, etc.) and alloys thereof, and oxides, sulfides, nitrides, silicides, carbides, phosphides, and the like thereof. Among these, as the metal-based negative electrode active material, an active material containing silicon (silicon-based negative electrode active material) is preferable. This is because the capacity of the lithium ion secondary battery can be increased by using the silicon-based negative electrode active material.

Examples of the silicon-based negative electrode active material include silicon (Si), an alloy containing silicon, SiO, SiO _x , and a composite of a Si-containing material and a conductive carbon obtained by coating or combining a Si-containing material with a conductive carbon. Etc. In addition, these silicon type negative electrode active materials may be used individually by 1 type, and may be used in combination of 2 types.
In addition, the compounding quantity and particle diameter of a negative electrode active material are not specifically limited, It can be made to be the same as that of the negative electrode active material used conventionally.

<Binder composition for non-aqueous secondary battery electrode>
As the binder composition for a non-aqueous secondary battery electrode, a binder composition for a non-aqueous secondary battery electrode containing the polymer (A) and the polyvalent cationic organic compound (B) described above is used.

Here, the content ratio of the binder composition in the slurry composition for a non-aqueous secondary battery electrode is an amount such that the amount of the polymer (A) is 0.1 parts by mass or more per 100 parts by mass of the electrode active material. The amount is preferably 0.3 parts by mass or more, more preferably 3 parts by mass or less, and even more preferably 1.5 parts by mass or less. If the slurry composition contains the binder composition in such an amount that the amount of the polymer (A) is within the above range, the swelling of the electrode mixture layer in the electrolytic solution is further suppressed, and the secondary battery The cycle characteristics can be further improved.

<Conductive material>
The conductive material is for ensuring electrical contact between the electrode active materials. Examples of the conductive material include carbon black (for example, acetylene black, ketjen black (registered trademark), furnace black, etc.), single-walled or multi-walled carbon nanotubes (multi-walled carbon nanotubes include cup stack type), carbon Conductive carbon materials such as nanohorns, vapor-grown carbon fibers, milled carbon fibers obtained by crushing polymer fibers after firing, single-layer or multilayer graphene, and carbon nonwoven fabric sheets obtained by firing nonwoven fabrics made of polymer fibers; Metal fibers or foils can be used.
These can be used alone or in combination of two or more.

In addition, it is preferable that the content rate of the electrically conductive material in the slurry composition for non-aqueous secondary battery electrodes is 0.1 mass part or more per 100 mass parts of electrode active materials, and is 0.5 mass part or more. Is more preferably 5 parts by mass or less, and more preferably 3 parts by mass or less. When the amount of the conductive material is within the above range, sufficient electrical contact between the electrode active materials can be ensured, and excellent battery characteristics (such as cycle characteristics) can be exhibited in the secondary battery.

<Other ingredients>
Other components that can be blended in the slurry composition are not particularly limited, and examples thereof include those similar to the other components that can be blended in the binder composition described above. Moreover, the other component may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

<Preparation of slurry composition>
The slurry composition described above can be prepared by dissolving or dispersing the above components in a solvent such as an organic solvent. Specifically, by mixing each of the above components and a solvent using a mixer such as a ball mill, sand mill, bead mill, pigment disperser, crushed grinder, ultrasonic disperser, homogenizer, planetary mixer, fill mix, etc. A slurry composition can be prepared. In addition, as a solvent used for preparation of a slurry composition, you may use the solvent contained in the binder composition.

Here, the order in which the above components are mixed in the solvent is not particularly limited, and can be any order. Specifically, when preparing the slurry composition, the above components can be mixed, for example, in any order of (1) to (3) below.
(1) The above components are mixed together.
(2) A binder composition containing the polymer (A) and the polyvalent cationic organic compound (B) and a conductive material are mixed to obtain a conductive material paste composition for a non-aqueous secondary battery electrode. An electrode active material is added to and mixed with the conductive material paste composition for an aqueous secondary battery electrode.
(3) After mixing the conductive material and the electrode active material, a binder composition containing the polymer (A) and the polyvalent cationic organic compound (B) is added to and mixed with the obtained mixture.

Among the above-mentioned components, it is preferable that the components are mixed in the order of (1) or (2). When the order of (2) is adopted, that is, the binder composition and the conductive material are mixed in advance, and the conductive material and the binder composition described above are included (that is, the conductive material, the polymer (A), When a conductive material paste composition for a non-aqueous secondary battery electrode (including a polyvalent cationic organic compound (B) and a solvent) is used, the polymer (A) is adsorbed on the surface of the conductive material, It can be dispersed well. As a result, excellent battery characteristics (such as cycle characteristics) can be exhibited in the secondary battery.
In the present invention, the non-aqueous secondary battery electrode conductive material paste composition is an intermediate product for preparing the non-aqueous secondary battery electrode slurry composition of the present invention. It is a paste-like composition which contains a material, a polymer (A), a polyvalent cationic organic compound (B), and a solvent, but does not contain an electrode active material.

(Electrode for non-aqueous secondary battery)
The electrode for a secondary battery of the present invention includes a current collector and an electrode mixture layer formed on the current collector, and the electrode mixture layer uses the above slurry composition for non-aqueous secondary battery electrodes. Is formed. That is, the electrode mixture layer contains at least an electrode active material, a polymer (A), and a polyvalent cationic organic compound (B) having a molecular weight of a predetermined value or less. Here, the polymer (A) and the polyvalent cationic organic compound (B) may form a crosslinked structure. That is, the electrode mixture layer may contain a crosslinked product of the polymer (A) and the polyvalent cationic organic compound (B). In addition, each component contained in the electrode mixture layer is contained in the slurry composition for non-aqueous secondary battery electrodes, and a suitable abundance ratio of each of these components is the slurry composition. It is the same as the suitable abundance ratio of each component in the inside.
And since the slurry composition containing the binder composition for nonaqueous secondary battery electrodes of the present invention is used in the electrode for nonaqueous secondary batteries of the present invention, the polymer (A) and the polyvalent cationic organic material are used. A rigid electrode mixture layer in which the compound (B) interacts firmly can be formed favorably on the current collector. Therefore, when the electrode is used, swelling of the electrode mixture layer in the electrolytic solution is suppressed, and a secondary battery excellent in battery characteristics such as cycle characteristics can be obtained.

<Method for producing electrode>
In addition, the electrode for non-aqueous secondary batteries of the present invention includes, for example, a step of applying the slurry composition described above on the current collector (application step), and a drying of the slurry composition applied on the current collector. And a step of forming an electrode mixture layer on the current collector (drying step).

<< Application process >>
The method for applying the slurry composition onto the current collector is not particularly limited, and a known method can be used. Specifically, as a coating method, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method, or the like can be used. At this time, the slurry composition may be applied to only one side of the current collector or may be applied to both sides. The thickness of the slurry film on the current collector after application and before drying can be appropriately set according to the thickness of the electrode mixture layer obtained by drying.

Here, as the current collector to which the slurry composition is applied, an electrically conductive and electrochemically durable material is used. Specifically, as the current collector, for example, a current collector made of iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum, or the like can be used. In addition, the said material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

<< Drying process >>
The method for drying the slurry composition on the current collector is not particularly limited, and a known method can be used. For example, a drying method using hot air, hot air, low-humidity air, vacuum drying method, infrared ray, electron beam, etc. The drying method by irradiation is mentioned. By drying the slurry composition on the current collector in this way, an electrode mixture layer is formed on the current collector, and a secondary battery electrode including the current collector and the electrode mixture layer can be obtained. it can. The drying temperature is preferably 60 ° C. or higher and 200 ° C. or lower, and more preferably 90 ° C. or higher and 150 ° C. or lower.
For example, a polymer having at least one of a carboxylic acid group, a sulfonic acid group and a phosphoric acid group is used as the polymer (A), and a compound containing an amino group is used as the polyvalent cationic organic compound (B). The polymer (A) and the polyvalent cationic organic compound (B) are cross-linked by an amide bond, further suppressing the swelling of the electrode mixture layer in the electrolyte solution, and the cycle of the secondary battery The characteristics can be further improved.

In addition, after the drying step, the electrode mixture layer may be subjected to pressure treatment using a die press or a roll press. The adhesion between the electrode mixture layer and the current collector can be improved by the pressure treatment. Moreover, when an electrode compound-material layer contains a curable polymer, it is preferable to harden the said polymer after formation of an electrode compound-material layer.

(Non-aqueous secondary battery)
The nonaqueous secondary battery of the present invention includes a positive electrode, a negative electrode, an electrolytic solution, and a separator, and uses the secondary battery electrode of the present invention as at least one of the positive electrode and the negative electrode. And since the non-aqueous secondary battery of this invention is equipped with the electrode for non-aqueous secondary batteries of this invention, it is excellent in battery characteristics, such as a cycle characteristic.
In the following, the case where the non-aqueous secondary battery is a lithium ion secondary battery will be described as an example, but the present invention is not limited to the following example.

<Electrode>
Here, as electrodes other than the electrode for non-aqueous secondary batteries described above that can be used for the non-aqueous secondary battery of the present invention, there is no particular limitation, and known electrodes used for manufacturing secondary batteries are known. An electrode can be used. Specifically, as an electrode other than the electrode for a non-aqueous secondary battery described above, an electrode formed by forming an electrode mixture layer on a current collector using a known manufacturing method can be used.

<Electrolyte>
As the electrolytic solution, an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is usually used. As the supporting electrolyte for the lithium ion secondary battery, for example, a lithium salt is used. Examples of the lithium salt include LiPF ₆ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAlCl ₄ , LiClO ₄ , CF ₃ SO ₃ Li, C ₄ F ₉ SO ₃ Li, CF ₃ COOLi, (CF ₃ CO) ₂ NLi , (CF ₃ SO ₂ ) ₂ NLi, (C ₂ F ₅ SO ₂ ) NLi, and the like. Among them, LiPF ₆ , LiClO ₄ , and CF ₃ SO ₃ Li are preferable, and LiPF ₆ is particularly preferable because it is easily dissolved in a solvent and exhibits a high degree of dissociation. In addition, electrolyte may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. Usually, the lithium ion conductivity tends to increase as the supporting electrolyte having a higher degree of dissociation is used, so that the lithium ion conductivity can be adjusted depending on the type of the supporting electrolyte.

The organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte. For example, dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), Carbonates such as butylene carbonate (BC) and ethyl methyl carbonate (EMC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide Etc. are preferably used. Moreover, you may use the liquid mixture of these solvents. Among these, carbonates are preferably used because they have a high dielectric constant and a wide stable potential region.
The concentration of the electrolyte in the electrolytic solution can be adjusted as appropriate. Further, known additives can be added to the electrolytic solution.

<Separator>
The separator is not particularly limited, and for example, those described in JP 2012-204303 A can be used. Among these, the film thickness of the entire separator can be reduced, thereby increasing the ratio of the electrode active material in the secondary battery and increasing the capacity per volume. A microporous film made of a resin such as polyethylene, polypropylene, polybutene, or polyvinyl chloride is preferable.

<Method for producing secondary battery>
The secondary battery of the present invention includes, for example, a positive electrode and a negative electrode that are stacked with a separator interposed between them, wound as necessary according to the shape of the battery, folded into a battery container, and electrolyzed in the battery container. It can be manufactured by injecting and sealing the liquid. In order to prevent an increase in pressure inside the secondary battery, overcharge / discharge, and the like, a fuse, an overcurrent prevention element such as a PTC element, an expanded metal, a lead plate, and the like may be provided as necessary. The shape of the secondary battery may be any of, for example, a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, and a flat shape.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the following description, “%”, “ppm”, and “parts” representing amounts are based on mass unless otherwise specified.
In addition, in a polymer produced by copolymerizing a plurality of types of monomers, the proportion of monomer units formed by polymerizing a certain monomer in the polymer is usually unless otherwise specified. This coincides with the ratio (preparation ratio) of the certain monomer in the total monomers used for polymerization of the polymer.
In Examples and Comparative Examples, the viscosity stability of the binder composition, the electrolyte swelling degree of the film made of the binder composition, and the cycle characteristics of the secondary battery were evaluated by the following methods.

<Viscosity stability>
The viscosity M0 immediately after preparation of the binder composition and the viscosity M1 after storage at 60 ° C. for 7 days were measured. The viscosity was measured using a B-type viscometer, temperature: 25 ° C., rotor: No. 4. Rotor rotation speed: 60 rpm.
And viscosity change rate (DELTA) M (= M1 / M0 * 100 (%)) was computed, and the following reference | standard evaluated. It shows that the viscosity stability of a binder composition is so high that the value of viscosity change rate (DELTA) M is small.
A: Viscosity change rate ΔM is less than 110% B: Viscosity change rate ΔM is 110% or more and less than 120% C: Viscosity change rate ΔM is 120% or more and less than 130% D: Viscosity change rate ΔM is 130% or more and less than 150% E : Viscosity change rate ΔM is 150% or more <Swelling degree of electrolyte solution>
The binder composition in the Teflon (registered trademark) petri dish was dried at 120 ° C. for 12 hours to obtain a film having a thickness of 1 mm. This film was punched into a circular shape having a diameter of 1.6 mm and used as a measurement sample (pseudo electrode mixture layer), and the weight W0 of the measurement sample was measured.
The obtained measurement material was stored in an electrolyte solution at 60 ° C. for 72 hours, and then the electrolyte solution adhering to the measurement sample was wiped off, and the weight W1 of the measurement sample was measured.
As the electrolytic solution, ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), and propyl propionate (PP) are EC: PC: EMC: PP = 2: 1. : A solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / liter in a mixed solvent mixed at 1: 6 (mass ratio) and further adding 1.5% by volume of vinylene carbonate as an additive was used.
And electrolyte solution swelling degree (DELTA) W (= W1 / W0x100 (%)) was computed, and the following reference | standard evaluated. It shows that swelling in the electrolyte solution of the electrode compound material layer obtained using a binder composition can be suppressed, so that the value of electrolyte solution swelling degree (DELTA) W is small.
A: electrolyte solution swelling degree ΔW is less than 600% B: electrolyte solution swelling degree ΔW is 600% or more and less than 800% C: electrolyte solution swelling degree ΔW is 800% or more and less than 1000% D: electrolyte solution swelling degree ΔW is 1000% or more Less than 2000% E: electrolyte solution swelling degree ΔW is 2000% or more <Cycle characteristics>
About the produced secondary battery, the operation which charges to 4.35V at 0.2C and discharges to 3.0V was repeated 3 times in 25 degreeC environment. Thereafter, the operation of charging at 1 CmA until the battery voltage reached 4.35 V and discharging at 1 CmA until the battery voltage reached 3.0 V was repeated 100 times in a 45 ° C. environment. Then, a capacity retention ratio ΔC = (C1 / C0) × 100 (%) was calculated from the first discharge capacity (C0) and the 100th discharge capacity (C1), and evaluated according to the following criteria. The higher the capacity retention ratio, the less the discharge capacity is reduced and the better the cycle characteristics.
A: Capacity maintenance ratio ΔC is 85% or more B: Capacity maintenance ratio ΔC is 80% or more and less than 85% C: Capacity maintenance ratio ΔC is 75% or more and less than 80% D: Capacity maintenance ratio ΔC is 70% or more and less than 75% E : Capacity maintenance ratio ΔC is less than 70%

Example 1
<Preparation of polymer (A)>
In a metal bottle, 180 parts of ion-exchanged water, 25 parts of an aqueous solution of sodium dodecylbenzenesulfonate having a concentration of 10% by mass, 5 parts of methacrylic acid as a binding functional group-containing monomer, and acrylonitrile 10 as a nitrile group-containing monomer Parts, 25 parts of 2-ethylhexyl acrylate as a (meth) acrylic acid ester monomer, and 0.5 part of t-dodecyl mercaptan as a molecular weight regulator are sequentially charged, and the inside gas is replaced with nitrogen three times. After that, 60 parts of 1,3-butadiene as a conjugated diene monomer was added. The metal bottle was kept at 5 ° C., 0.1 part of cumene hydroperoxide as a polymerization initiator was added, and polymerization was performed for 16 hours while rotating the metal bottle. Next, 0.1 part of a hydroquinone aqueous solution having a concentration of 10% by mass as a polymerization terminator was added to terminate the polymerization reaction, and then the residual monomer was removed using a rotary evaporator at a water temperature of 60 ° C. (Solid content concentration of about 30% by mass) was obtained.
Next, in the autoclave, the aqueous dispersion prepared above and the palladium catalyst (1% by mass) so that the palladium content relative to the dry weight of the polymer contained in the aqueous dispersion obtained above was 750 ppm. A solution obtained by mixing a palladium acetate / acetone solution and ion-exchanged water at a ratio of 1: 1 (mass ratio) was added. And hydrogenation reaction was performed at a hydrogen pressure of 3 MPa and a temperature of 50 ° C. for 6 hours to obtain a hydrogenated polymer.
Subsequently, NMP as a solvent was added to the aqueous dispersion of the obtained hydrogenated polymer so that the solid content concentration of the hydrogenated polymer was 7%. Then, distillation under reduced pressure was performed at 90 ° C. to remove water and excess NMP to obtain an NMP solution (solid content concentration 8%) of the polymer (A) (hydrogenated polymer).
<Preparation of polyvalent cationic organic compound (B)>
As the polyvalent cationic organic compound (B), polyethyleneimine (number average molecular weight: 600, “Epomin SP-006”, manufactured by Nippon Shokubai Co., Ltd.) was prepared. And this NMP solution of polyethyleneimine (solid content concentration 8%) was prepared.
<Preparation of positive electrode binder composition>
The above-mentioned NMP solution of polymer (A) and NMP solution of polyethyleneimine were mixed so that the mixing ratio was 100: 5 in terms of solid content to obtain a positive electrode binder composition. Using this positive electrode binder composition, the viscosity stability and the degree of swelling of the electrolyte were evaluated. The results are shown in Table 1.
<Preparation of slurry composition for positive electrode>
100 parts of lithium cobaltate (LiCoO ₂ , volume average particle size: 12 μm) as a positive electrode active material and Ketjen black (made by Lion Corporation, special oil furnace carbon powder: number particle size 40 nm, specific surface area) as a conductive material 800 m ^{2 /} g) 1.5 parts, an amount of positive electrode binder composition in which the polymer (A) is 0.6 parts (in terms of solid content), and NMP of polyvinylidene fluoride (PVDF) as a binder A slurry composition for a positive electrode was prepared by mixing 0.6 part of the solution (in terms of solid content) and NMP as an additional solvent using a planetary mixer. The amount of additional NMP is within a range of 5000 ± 200 mPa · s of the viscosity of the obtained slurry composition for positive electrode (using a B-type viscometer. Temperature: 25 ° C., rotor: No. 4, rotor rotational speed: 60 rpm). It adjusted so that it might become in.
<Preparation of positive electrode>
The obtained positive electrode slurry composition was applied to one surface of a current collector made of an aluminum foil having a thickness of 15 μm so that the coating amount after drying was 20 mg / cm ² . The applied slurry composition was dried at 90 ° C. for 20 minutes and 120 ° C. for 20 minutes, and then heat-treated at 150 ° C. for 2 hours to obtain a positive electrode raw material. And the obtained positive electrode raw material was rolled with the roll press, and the positive electrode provided with the positive electrode compound-material layer whose density is 3.7 g / cm < ³ > on aluminum foil (current collector) was obtained.
<Production of negative electrode>
100 parts of spherical artificial graphite (volume average particle size: 12 μm) as a negative electrode active material, 1 part of styrene-butadiene copolymer as a binder, 1 part of carboxymethylcellulose as a thickener, and an appropriate amount as a dispersion medium The negative electrode slurry composition was prepared by mixing the water in a planetary mixer.
The obtained slurry composition for negative electrode was applied to one side of a current collector made of a copper foil having a thickness of 15 μm so that the coating amount after drying was 10 mg / cm ² . And the apply | coated slurry composition was dried at 60 degreeC for 20 minutes and 120 degreeC for 20 minutes, and the negative electrode original fabric was obtained. And the obtained negative electrode original fabric was rolled with the roll press, and the negative electrode provided with the negative electrode compound-material layer whose density is 1.5 g / cm < ³ > on copper foil (current collector) was obtained.
<Preparation of separator>
A single-layer polypropylene separator (width 65 mm, length 500 mm, thickness 25 μm, manufactured by a dry method, porosity 55%) was cut out to a square of 4.4 cm × 4.4 cm.
<Manufacture of secondary batteries>
An aluminum packaging exterior was prepared as the battery exterior. Then, the positive electrode obtained above was cut into a 4 cm × 4 cm square and arranged so that the surface on the current collector side was in contact with the aluminum packaging exterior. The square separator obtained above was disposed on the positive electrode mixture layer of the positive electrode. Further, the negative electrode obtained above was cut into a square of 4.2 cm × 4.2 cm, and this was placed on the separator so that the surface on the negative electrode mixture layer side faces the separator. Furthermore, in order to seal the opening of the aluminum packaging material exterior, it filled with electrolyte solution, 150 degreeC heat-sealed and the aluminum packaging material exterior was closed, and the lithium ion secondary battery was obtained. As the electrolytic solution, ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), and propyl propionate (PP) are EC: PC: EMC: PP = 2: 1. : A solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / liter in a mixed solvent mixed at 1: 6 (mass ratio) and further adding 1.5% by volume of vinylene carbonate as an additive was used.
And the cycle characteristic was evaluated using the obtained lithium ion secondary battery. The results are shown in Table 1.

(Examples 2, 4 to 15)
The polymer (A), the positive electrode binder composition, the positive electrode slurry composition, and the positive electrode were prepared in the same manner as in Example 1 except that the monomer composition shown in Table 1 was adopted during the preparation of the polymer (A). A negative electrode and a secondary battery were produced. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
When the polymer (A) was prepared, the monomer composition shown in Table 1 was adopted, and when the positive electrode binder composition was prepared, N, N′-bis was replaced with an NMP solution of polyethyleneimine. The polymer (A) was prepared in the same manner as in Example 1 except that an NMP solution (solid content concentration 8%) of (3-phenyl-2-propenylidene) -1,6-hexanediamine (molecular weight: 344) was used. A positive electrode binder composition, a positive electrode slurry composition, a positive electrode, a negative electrode, and a secondary battery were prepared. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Examples 16 and 17)
The polymer (A) and the positive electrode binder were prepared in the same manner as in Example 1 except that the amount of the polyvalent cationic organic compound (B) was changed as shown in Table 1 when preparing the positive electrode binder composition. A composition, a slurry composition for a positive electrode, a positive electrode, a negative electrode, and a secondary battery were produced. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Examples 18 and 19)
In preparing the positive electrode binder composition, polyethyleneimine (number average molecular weight: 1200, “Epomin SP-012”, manufactured by Nippon Shokubai Co., Ltd.) or polyethylene is used instead of the polyethyleneimine (number average molecular weight: 600) NMP solution. In the same manner as in Example 1 except that an NMP solution (solid content concentration: 8%) of imine (number average molecular weight: 1800, “Epomin SP-018”, manufactured by Nippon Shokubai Co., Ltd.) was used, the polymer (A), A positive electrode binder composition, a positive electrode slurry composition, a positive electrode, a negative electrode, and a secondary battery were produced. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Examples 20 to 23)
In preparing the positive electrode binder composition, N, N′-bis (3-phenyl-2-propenylidene) -1,6-hexanediamine (in place of the NMP solution of polyethyleneimine (number average molecular weight: 600)) ( Molecular weight: 344), polyallylamine (number average molecular weight: 1600, “PAA-01”, manufactured by Nitteau Medical), diethylenetriamine (molecular weight: 103), or ethylenediamine (molecular weight: 60) in NMP solution (solid content concentration 8%) A polymer (A), a positive electrode binder composition, a positive electrode slurry composition, a positive electrode, a negative electrode, and a secondary battery were produced in the same manner as Example 1 except that was used. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
In preparing the positive electrode binder composition, the polymer (A), the positive electrode binder composition, and the positive electrode slurry composition were the same as in Example 1 except that the polyvalent cationic organic compound (B) was not used. Product, positive electrode, negative electrode, and secondary battery were prepared. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
In preparing the binder composition for the positive electrode, NMP of polyethyleneimine (number average molecular weight: 10,000, “Epomin SP-200”, manufactured by Nippon Shokubai Co., Ltd.) is used instead of the NMP solution of polyethyleneimine (number average molecular weight: 600). A polymer (A), a positive electrode binder composition, a positive electrode slurry composition, a positive electrode, a negative electrode, and a secondary battery were prepared in the same manner as in Example 1 except that the solution (solid content concentration 8%) was used. did. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
The polymer (A), the positive electrode binder composition, the positive electrode slurry composition, and the positive electrode were prepared in the same manner as in Example 1 except that the monomer composition shown in Table 1 was adopted during the preparation of the polymer (A). A negative electrode and a secondary battery were produced. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
In preparing the positive electrode binder composition, an aluminum chelate (manufactured by Kawaken Fine Chemical Co., Ltd., product name “Aluminum Chelate A (W)”, aluminum tris (acetylacetonate)) is used instead of the polyvalent cationic organic compound (B). Except having used, it carried out similarly to Example 1, and produced the polymer (A), the positive electrode binder composition, the positive electrode slurry composition, the positive electrode, the negative electrode, and the secondary battery. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

In Table 1 shown below,
“COOH” refers to a carboxylic acid group;
“AA” indicates an acrylic acid unit;
“IA” indicates an itaconic acid unit;
“MAA” indicates a methacrylic acid unit;
“MBM” indicates a monobutyl maleate unit;
“MMA” for methyl methacrylate units
“EA” indicates an ethyl acrylate unit;
“BA” represents an n-butyl acrylate unit;
“2-EHA” refers to a 2-ethylhexyl acrylate unit;
“AN” represents an acrylonitrile unit;
“BD” indicates 1,3-butadiene units or 1,3-butadiene hydride units;
“PEI” indicates polyethyleneimine,
“NBH” refers to N, N′-bis (3-phenyl-2-propenylidene) -1,6-hexanediamine,
“PAA” refers to polyallylamine,
“DETA” refers to diethylenetriamine,
“ED” represents ethylenediamine,
“AL” indicates an aluminum chelate.

From Table 1, in Examples 1 to 23 using a binder composition containing a polymer (A) having a binding functional group and a polyvalent cationic organic compound (B) having a molecular weight of a predetermined value or less, A binder composition having excellent viscosity stability and capable of forming an electrode mixture layer in which swelling in the electrolyte is suppressed is obtained, and a secondary battery having excellent cycle characteristics is manufactured. I understand that I can do it.
On the other hand, from Table 1, in Comparative Example 1 using a binder composition containing a polymer (A) having a binding functional group and not containing a polyvalent cationic organic compound (B) having a molecular weight of a predetermined value or less. It can be seen that the swelling of the electrode mixture layer in the electrolytic solution cannot be sufficiently suppressed, and the cycle characteristics of the secondary battery are deteriorated.
Moreover, from Table 1, the polymer (A) having a binding functional group and the polyvalent cationic organic compound (B) are included, but the molecular weight of the polyvalent cationic organic compound (B) exceeds a predetermined value. In the comparative example 2 using a binder composition, it turns out that a binder composition is inferior in viscosity stability, and the cycling characteristics of a secondary battery will fall.
And from Table 1, in Comparative Example 3 using a binder composition containing a polymer having no binding functional group and a polyvalent cationic organic compound (B) having a molecular weight of a predetermined value or less, an electrode It can be seen that the swelling of the composite layer in the electrolytic solution cannot be sufficiently suppressed, and the cycle characteristics of the secondary battery are deteriorated.
Furthermore, from Table 1, in Comparative Example 4 using the polymer (A) having a binding functional group and a binder composition containing an aluminum chelate, the binder composition is inferior in viscosity stability, and the cycle characteristics of the secondary battery. It turns out that falls. These reductions in performance are presumed to be due to aluminum ions derived from the aluminum chelate. Specifically, the decrease in viscosity stability is presumed to be because the high mobility of aluminum ions in the solvent causes a cross-linking reaction with the polymer (A) to thicken the polymer (A). The In addition, the deterioration of the cycle characteristics is due to a temperature increase due to shear during preparation of the slurry composition, so that aluminum ions cause a crosslinking reaction with the polymer (A), and as a result, the polymer (A) is difficult to cover the conductive material. This is presumably because the dispersibility of the conductive material is impaired.

Claims

A binder composition for a non-aqueous secondary battery electrode, comprising: a polymer having a functional group capable of binding to a cationic group; and an organic compound having two or more cationic groups and having a molecular weight of 8000 or less.
The non-aqueous secondary battery according to claim 1, wherein the functional group capable of binding to the cationic group is at least one selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a hydroxyl group. Electrode binder composition.
The non-aqueous secondary according to claim 1, wherein the polymer contains a monomer unit containing a functional group capable of binding to a cationic group in a proportion of 0.1% by mass or more and 20% by mass or less. Binder composition for battery electrodes.
The binder composition for a non-aqueous secondary battery electrode according to any one of claims 1 to 3, comprising 0.1 to 20 parts by mass of the organic compound per 100 parts by mass of the polymer.
The polymer includes a nitrile group-containing monomer unit, and at least one of a conjugated diene monomer unit and an alkylene structural unit,
A ratio of the nitrile group-containing monomer unit in the polymer is 5% by mass or more and 35% by mass or less, and a total of a ratio of the conjugated diene monomer unit and a ratio of the alkylene structural unit in the polymer. The binder composition for a non-aqueous secondary battery electrode according to any one of claims 1 to 4, wherein is from 30% by mass to 90% by mass.
A conductive material paste composition for a non-aqueous secondary battery electrode, comprising a conductive material and the binder composition for a non-aqueous secondary battery electrode according to any one of claims 1 to 5.
A non-aqueous secondary battery electrode binder composition according to any one of claims 1 to 5 or a non-aqueous secondary battery electrode conductive material paste composition according to claim 6 comprising: an electrode active material; A slurry composition for an aqueous secondary battery electrode.
A non-aqueous secondary battery electrode comprising an electrode mixture layer formed using the slurry composition for a non-aqueous secondary battery electrode according to claim 7.
A positive electrode, a negative electrode, an electrolyte and a separator;
A nonaqueous secondary battery, wherein at least one of the positive electrode and the negative electrode is the electrode for a nonaqueous secondary battery according to claim 8.