JP2023106633A - Binder composition for nonaqueous secondary battery, composition for electrode, electrode sheet and nonaqueous secondary battery, and methods for manufacturing electrode sheet and nonaqueous secondary battery - Google Patents

Abstract

To provide a binder composition for a nonaqueous secondary battery, which allows a composition (slurry) superior in solid particle dispersibility to be obtained, which can sufficiently rise a binding property between electrode active substance particles or between an electrode active substance particle and a collector when the composition is used to form an electrode active substance layer, and which can achieve a nonaqueous secondary battery of sufficiently low resistance even in such a case that an electrode active substance that causes a large volume change during a charge/discharge operation is used for the electrode active substance layer and further achieve a satisfactorily long cycle life in the nonaqueous secondary battery.SOLUTION: Provided are: a binder composition for a nonaqueous secondary battery comprising a binder formed by a polymer having a constituent including a betaine structure; a composition for an electrode, comprising the binder composition and an electrode active substance; an electrode sheet having a layer formed by the composition for an electrode and a manufacturing method thereof; and a nonaqueous secondary battery of which at least one of positive and negative electrode active substance layers is a layer formed by the composition for an electrode, and a manufacturing method thereof.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a binder composition for nonaqueous secondary batteries, an electrode composition, an electrode sheet, a nonaqueous secondary battery, a method for producing an electrode sheet, and a method for producing a nonaqueous secondary battery.

Non-aqueous secondary batteries, typified by lithium-ion secondary batteries, are used as power sources for portable electronic devices such as personal computers, video cameras, and mobile phones. Recently, against the background of the global environmental issue of reducing carbon dioxide emissions, it is becoming popular as a power source for transportation equipment such as automobiles, and as a power storage application such as nighttime power and power generated by natural energy generation.

The electrodes (positive electrode and negative electrode) of the lithium ion secondary battery have an electrode active material layer (positive electrode active material layer and negative electrode active material layer), and this electrode active material layer can absorb or release lithium ions during charging and discharging. Contains electrode active material particles. In addition, since electrons are also transported between the electrode active material particles or between the electrode active material particles and the current collector, it is required to ensure electron conductivity. The binding between the electrode active material particles or between the electrode active material particles and the current collector is important for the efficiency of this electron conduction, and the electrode active material layer usually contains a binder. However, the binder itself has a low electron-transporting ability, and improvement in binding property and improvement in electron conductivity are usually in a so-called trade-off relationship with each other.

An electrode for a lithium ion secondary battery is usually formed by applying an electrode-forming composition (slurry) onto a current collector and drying it. Therefore, a slurry for electrode formation is prepared by dispersing an electrode active material and a binder in a liquid medium. Against the background of the growing interest in environmental issues in recent years, a water-based liquid medium is required, and water-based binders suitable for water-based slurries have been developed.
For example, Patent Document 1 contains 50 to 80% by mass of structural units derived from ethylenically unsaturated carboxylate monomers, and contains 20 to 50% by mass of structural units derived from ethylenically unsaturated carboxylic acid ester monomers. , describes the use of a water-soluble polymer having a specific viscosity as an aqueous electrode binder for a secondary battery.
Further, in Patent Document 2, an ethylenically unsaturated monomer that may contain a phosphate group-containing ethylenically unsaturated monomer, a surfactant that may contain a phosphate group-containing surfactant, and A water-dispersed binder for non-aqueous battery electrodes is described which is obtained by emulsion polymerization of a composition containing at least one neutralizing agent selected from alkali metals and alkaline earth metals.

In order to further increase the capacity of lithium-ion secondary batteries, extensive studies have been conducted on the use of silicon-based active materials as negative electrode active materials. High energy density can be achieved by using a silicon-based active material for the negative electrode. However, the silicon-based active material absorbs a large amount of lithium ions during charging and expands greatly, and the shrinkage width of the silicon-based active material during discharging also increases accordingly. Therefore, in a lithium-ion battery using a silicon-based active material as a negative electrode active material, the negative electrode active material undergoes a large volume change during charging and discharging, and battery performance tends to deteriorate due to repeated charging and discharging. In other words, there are restrictions on improving the cycle life.
As a technique for dealing with such problems, for example, Patent Document 3 discloses a negative electrode active material containing 20% by mass or more of silicon particles having a median diameter of 0.1 to 2 μm, a (meth)acrylamide skeleton-containing monomer, and sulfonic acid. A slurry for a lithium ion battery negative electrode, comprising poly(meth)acrylamide, which is a radical copolymer of a monomer group containing a group-substituted unsaturated hydrocarbon group-containing monomer and exhibits a specific viscosity in an aqueous solution of a specific concentration, and water. is described. According to the technique described in Patent Document 3, the dispersibility of the slurry can be improved, the electrode formed from this slurry has excellent flexibility, and a lithium ion secondary battery with a long cycle life can be obtained.

JP 2015-18776 A Japanese Patent No. 6462125 JP 2018-6334 A

With the expansion of the use of non-aqueous secondary batteries, higher energy density, lower resistance, and further improvement in cycle life are required for non-aqueous secondary batteries. However, as a result of examining conventional electrode binders including the electrode binders described in the above patent documents, the present inventors have found that high energy density non-aqueous secondary batteries can be obtained by using silicon-based active materials as negative electrode active materials. It has become clear that it is difficult to sufficiently suppress the battery resistance and the cycle life has not yet reached the desired high level.

According to the present invention, a composition (slurry) having excellent dispersibility of these solid particles can be obtained by mixing solid particles such as an electrode active material and a conductive agent, and this composition can be used to activate an electrode. By forming the material layer, the adhesion between the electrode active material particles or between the electrode active material particles and the current collector can be sufficiently improved, and the electrode active material that undergoes a large volume change during charging and discharging can be used as an electrode. For non-aqueous secondary batteries, the resistance of the obtained non-aqueous secondary battery can be sufficiently reduced even when used in the active material layer, and the cycle life of the non-aqueous secondary battery can be sufficiently prolonged. An object of the present invention is to provide a binder composition. Another object of the present invention is to provide an electrode composition obtained by combining the binder composition and the electrode active material, and an electrode sheet and a non-aqueous secondary battery using the electrode composition. A further object of the present invention is to provide a method for manufacturing the electrode sheet and the non-aqueous secondary battery.

In view of the above problems, the present inventors conducted various studies on the polymer structure that constitutes the binder. As a result, when a binder composition containing an aqueous polymer having a constituent component containing a betaine structure in an aqueous medium is mixed with solid particles such as an electrode active material and a conductive agent, aggregation of the solid particles is suppressed. If this composition is used to form an electrode active material layer, it is possible to obtain a composition in which solid particles are dispersed to sufficiently small particle diameters, and if this composition is used to form an electrode active material layer, there will be no gap between the electrode active material particles or between the electrode active material particles and the current collector. By incorporating an electrode including this electrode active material layer into a non-aqueous secondary battery, the resistance of the obtained non-aqueous secondary battery can be effectively suppressed, They also found that the cycle life can be sufficiently prolonged. The present invention has been completed through further studies based on these findings.

式中、Ｒ^３１～Ｒ^３３は各々独立に水素原子、シアノ基、ハロゲン原子又は炭素数１～２４のアルキル基を示す。
Ｒ^３４は水素原子、ヒドロキシ基、炭素数１～１２のアルキル基、フェニル基、脂肪族環基又はハロゲン原子を示す。
Ｙ^２１はイミノ基又は酸素原子を示す。
Ｌ^４１は炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、若しくはカルボニル基、又はこれらを組み合わせた連結基を示す。ただし、Ｌ^４１のＲ^３４と結合する側が炭素数１～１６のアルキレン基である場合、Ｒ^３４は水素原子、ヒドロキシ基、フェニル基、脂肪族環基又はハロゲン原子を示す。
＜６＞
上記式（Ｏ－３１）で表される構成成分が、ガラス転移温度が６０℃以下の構成成分を含む、＜５＞に記載の非水二次電池用バインダー組成物。
＜７＞
上記ポリマーの重量平均分子量が１０００００以上である、＜１＞～＜６＞のいずれか１つに記載の非水二次電池用バインダー組成物。
＜８＞
前記バインダー組成物中の水の含有量が１０質量％以上である、＜１＞～＜７＞のいずれか１つに記載の非水二次電池用バインダー組成物。
＜９＞
＜１＞～＜８＞のいずれか１つに記載の非水二次電池用バインダー組成物と、周期律表第一族又は第二族に属する金属のイオンの挿入放出が可能な電極活物質とを含む電極用組成物。
＜１０＞
＜９＞に記載の電極用組成物で構成した層を有する電極シート。
＜１１＞
正極活物質層とセパレータと負極活物質層とをこの順で有する非水二次電池であって、上記正極活物質層及び上記負極活物質層の少なくとも１つの層が、＜９＞に記載の電極用組成物で構成した層である、非水二次電池。
＜１２＞
＜９＞に記載の電極用組成物を用いて成膜する工程を含む、電極シートの製造方法。
＜１３＞
＜１２＞に記載の製造方法により得られた電極シートを非水二次電池の電極に組み込むことを含む、非水二次電池の製造方法。 That is, the above problems have been solved by the following means.
<1>
A binder composition for a non-aqueous secondary battery, comprising a binder composed of a polymer having a component containing a betaine structure.
<2>
The nonaqueous secondary battery according to <1>, wherein the polymer has a component having a salt structure of at least one of carboxylate, sulfonate, phosphate, phosphonate, nitrate and ammonium salt. binder composition.
<3>
<2>, wherein the salt structure is at least one of carboxylate, sulfonate, phosphate, phosphonate, and nitrate, and the salt structure has a counter ion derived from a polyvalent amine. A binder composition for water secondary batteries.
<4>
<1> to <3>, wherein the polymer has a swelling rate of 1% or more and less than 200% in a solvent obtained by mixing ethylene carbonate and ethyl methyl carbonate at a mass ratio of ethylene carbonate/ethyl methyl carbonate=1/2. The binder composition for non-aqueous secondary batteries according to any one of the above.
<5>
The binder composition for nonaqueous secondary batteries according to any one of <1> to <4>, wherein the polymer has a component represented by the following formula (O-31).

In the formula, R ³¹ to R ³³ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group having 1 to 24 carbon atoms.
R ³⁴ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a phenyl group, an aliphatic cyclic group or a halogen atom.
^Y21 represents an imino group or an oxygen atom.
L ⁴¹ represents an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, or a linking group combining these. However, when the side of L ⁴¹ that bonds to R ³⁴ is an alkylene group having 1 to 16 carbon atoms, R ³⁴ represents a hydrogen atom, a hydroxy group, a phenyl group, an aliphatic cyclic group or a halogen atom.
<6>
The binder composition for non-aqueous secondary batteries according to <5>, wherein the component represented by formula (O-31) includes a component having a glass transition temperature of 60° C. or lower.
<7>
The binder composition for non-aqueous secondary batteries according to any one of <1> to <6>, wherein the polymer has a weight average molecular weight of 100,000 or more.
<8>
The binder composition for non-aqueous secondary batteries according to any one of <1> to <7>, wherein the water content in the binder composition is 10% by mass or more.
<9>
The binder composition for a non-aqueous secondary battery according to any one of <1> to <8>, and an electrode active material capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table. and a composition for an electrode.
<10>
An electrode sheet having a layer composed of the electrode composition according to <9>.
<11>
A non-aqueous secondary battery having a positive electrode active material layer, a separator, and a negative electrode active material layer in this order, wherein at least one layer of the positive electrode active material layer and the negative electrode active material layer is the layer according to <9>. A non-aqueous secondary battery, which is a layer composed of an electrode composition.
<12>
A method for producing an electrode sheet, comprising forming a film using the electrode composition according to <9>.
<13>
A method for producing a non-aqueous secondary battery, comprising incorporating the electrode sheet obtained by the production method according to <12> into an electrode of the non-aqueous secondary battery.

By mixing the binder composition for a non-aqueous secondary battery of the present invention with solid particles such as an electrode active material and a conductive agent, a composition (slurry) having excellent dispersibility of these solid particles can be obtained. can. The binder composition for a non-aqueous secondary battery, the electrode composition, and the electrode sheet of the present invention can be used between the electrode active material particles or together with the electrode active material particles in a non-aqueous secondary battery in which an electrode is produced using these. It is possible to sufficiently improve the binding property between the electric body and the low resistance of the non-aqueous secondary battery even when using an electrode active material that has a large volume change during charging and discharging, and the non-aqueous secondary battery. The cycle life of the secondary battery can also be sufficiently extended.
In the non-aqueous secondary battery of the present invention, the adhesion between the electrode active material particles or between the electrode active material particles and the current collector is sufficiently enhanced, and the electrode active material has a large volume change during charging and discharging. Even when the material is adopted, it is possible to realize a low resistance when the battery is driven, and it has a sufficiently long cycle life.
According to the method for producing an electrode sheet of the present invention, the electrode sheet of the present invention can be obtained. Further, according to the method for manufacturing a non-aqueous secondary battery of the present invention, the non-aqueous secondary battery of the present invention can be obtained.

FIG. 1 is a vertical cross-sectional view schematically showing the basic lamination structure of a non-aqueous secondary battery.

In the description of the present invention, a numerical range represented using "-" means a range including the numerical values described before and after "-" as lower and upper limits.
In the present specification, the expression of a compound (for example, when it is called with a compound at the end) is used to mean the compound itself, its salts, and its ions. It also includes derivatives in which a part of the structure is changed, such as by introducing a substituent, as long as the desired effect is achieved.
In the present specification, when a substituent has a dissociable hydrogen atom (a group in which a hydrogen atom is dissociated by the action of a base), this substituent includes ions or salts.
In the present specification, substituents, linking groups, etc. (hereinafter referred to as substituents, etc.) for which substitution or unsubstitution is not specified are intended to mean that the group may have an appropriate substituent. Therefore, in this specification, even when simply described as "- group" (eg, "alkyl group"), this "- group" (eg, "alkyl group") does not have a substituent In addition to embodiments (eg, "unsubstituted alkyl group"), embodiments with further substituents (eg, "substituted alkyl group") are also included. This also applies to compounds that are not specified as substituted or unsubstituted. Preferred substituents include the substituent T described later.
When simply referred to as a "substituent" in the present specification, a substituent selected from substituents T described later is preferably applied.
In this specification, when there are multiple substituents or the like indicated by a specific symbol, or when multiple substituents or the like are defined simultaneously or alternatively, the respective substituents or the like may be the same or different from each other. means good. Further, even if not otherwise specified, when a plurality of substituents and the like are adjacent to each other, they may be connected to each other or condensed to form a ring.
In this specification, when a polymer has a plurality of constituents with the same designation (indicated by the same general formula), each constituent may be the same or different.
In the present invention, the term "non-aqueous secondary battery" includes both non-aqueous electrolyte secondary batteries and all-solid secondary batteries. "Non-aqueous electrolyte" means an electrolyte that does not substantially contain water. That is, the "non-aqueous electrolyte" may contain a small amount of water as long as the effects of the present invention are not impaired. In the present invention, the "non-aqueous electrolyte" has a water concentration of 1000 ppm (by mass) or less, preferably 100 ppm or less, more preferably 20 ppm or less. It is practically difficult to make the non-aqueous electrolyte completely anhydrous, and usually contains 1 ppm or more of water. An "all-solid secondary battery" means a secondary battery using a solid electrolyte such as an inorganic solid electrolyte or a solid polymer electrolyte without using a liquid as an electrolyte.

[Binder composition for non-aqueous secondary battery]
The binder composition for non-aqueous secondary batteries of the present invention (also referred to as "binder composition of the present invention") is a binder composition suitable as a material for forming members or constituent layers constituting non-aqueous secondary batteries. . Typically, the binder composition of the present invention is mixed with an electrode active material (positive electrode active material or negative electrode active material, collectively referred to simply as "active material") to form an electrode of a non-aqueous secondary battery ( positive electrode and/or negative electrode) can be used to form an active material layer. In addition, the binder composition of the present invention may be used by coating it on the surface of a separator of a non-aqueous electrolyte secondary battery in order to form a heat-resistant layer, or may be used as a binder for coating a current collector. can.
The binder composition of the present invention contains a polymer having a component containing a betaine structure as a binder component. Also, the binder composition of the present invention contains a liquid medium for dissolving or dispersing the above polymer. The liquid medium is usually an aqueous medium containing water. In the present invention, the "aqueous medium containing water" is water or a mixed solution of water and a water-soluble organic solvent, and may contain a neutralizing agent to be described later. The term "water-soluble organic solvent" refers to an organic solvent that mixes with water without causing phase separation, and includes, for example, N-methylpyrrolidone, methanol, ethanol, acetone, and tetrahydrofuran.
It is preferable that the polymer, which is the binder component, is dissolved in the liquid medium.

<Polymer>
The binder composition of the present invention contains a polymer having a component containing a betaine structure (a component derived from a monomer containing a betaine structure, hereinafter also referred to as "component (a)"). A "betaine structure" has a positive charge and a negative charge at non-adjacent positions in the same molecule, no dissociable hydrogen atoms are bonded to the atoms with positive charges, and the molecule as a whole is uncharged. means a structure that is
A polymer having a constituent component containing a betaine structure can act with affinity to both positive and negative charges that may be possessed by solid particles such as electrode active materials and conductive aids. In the state where the substance layer is formed, the binding property between the solid particles can be further enhanced. On the other hand, when an electrode composition (slurry) to be described later is prepared, the repulsion between positive charges or negative charges contributes to the improvement of the dispersibility of solid particles, effectively aggregating solid particles in the slurry. can be reduced to
Therefore, if the constituent component of the polymer has a betaine structure, it is possible to exhibit the desired effects described above.

The betaine structure of the component (a) includes, for example, a carbobetaine structure, a sulfobetaine structure, or a phosphobetaine structure. Here, the carboxy group dissociated from the carbobetaine structure constitutes the negative charge of the betaine structure, the sulfo group dissociated from the sulfobetaine structure constitutes the negative charge of the betaine structure, and the phosphate dissociated from the phosphobetaine structure A betaine structure in which the group constitutes the negative charge of the betaine structure.
The betaine structure of component (a) usually has an ammonium cation structure, a sulfonium cation structure or a phosphonium cation structure as a positive charge, and more preferably has a quaternary ammonium cation structure.
The component (a) preferably has a betaine structure in its side chain from the viewpoint of enhancing the binding efficiency with solid particles. In this case, the main chain of the polymer can be formed by a polymerization reaction of ethylenically unsaturated groups (carbon-carbon double bonds).

The component (a) can be represented, for example, by any one of the following formulas (J-1) to (J-4).

In the formulas, R ¹¹ to R ¹³ , R ¹⁶ to R ¹⁸ , R ²¹ to R ²³ and R ²⁶ to R ²⁸ each independently represent a hydrogen atom, a cyano group, a halogen atom or an alkyl group. R ¹⁴ , R ¹⁵ , R ¹⁹ , R ²⁰ , R ²⁴ , R ²⁵ , R ²⁹ , R ³⁰ and R ³¹ each independently represent a hydrogen atom or a substituent. L ¹¹ to L ¹⁸ represent divalent linking groups.

Halogen atoms that can be used as R ¹¹ to R ¹³ , R ¹⁶ to R ¹⁸ , R ²¹ to R ²³ and R ²⁶ to R ²⁸ include, for example, fluorine, chlorine, bromine and iodine atoms. The halogen atoms that can be taken as R ¹¹ to R ¹³ , R ¹⁶ to R ¹⁸ , R ²¹ to R ²³ and R ²⁶ to R ²⁸ are preferably fluorine atoms or chlorine atoms.

The alkyl groups that can be used as R ¹¹ to R ¹³ , R ¹⁶ to R ¹⁸ , R ²¹ to R ²³ and R ²⁶ to R ²⁸ may be linear or branched. The number of carbon atoms in the alkyl group that can be taken as R ¹¹ to R ¹³ , R ¹⁶ to R ¹⁸ , R ²¹ to R ²³ and R ²⁶ to R ²⁸ is preferably 1 to 24, more preferably 1 to 12, and more preferably 1 to 8. More preferably, 1 to 4 are particularly preferable. A particularly preferred example of this alkyl group is methyl or ethyl, with methyl being preferred.
R ¹¹ , R ¹² , R ¹⁶ , R ¹⁷ , R ²¹ , R ²² , R ²⁶ and R ²⁷ are preferably hydrogen atoms. Also, R ¹³ , R ¹⁸ , R ²³ and R ²⁸ are preferably hydrogen atoms or alkyl groups.

R ¹⁴ , R ¹⁵ , R ¹⁹ , R ²⁰ , R ²⁴ , R ²⁵ , R ²⁹ , R ³⁰ and R ³¹ are preferably groups selected from substituents T described later, more preferably alkyl groups or aryl groups.
Preferred forms of the alkyl group that can be taken as R ¹⁴ , R ¹⁵ , R ¹⁹ , R ²⁰ , R ²⁴ , R ²⁵ , R ²⁹ , R ³⁰ and R ³¹ are the same as the preferred forms of the alkyl group that can be taken as R ¹¹ above. is. The aryl group that can be taken as R ¹⁴ , R ¹⁵ , R ¹⁹ , R ²⁰ , R ²⁴ , R ²⁵ , R ²⁹ , R ³⁰ and R ³¹ preferably has 6 to 20 carbon atoms, more preferably 6 to 15 carbon atoms. 6 to 12 are more preferred, and 6 to 10 are particularly preferred. A particularly preferred embodiment of this aryl group is phenyl.

L ¹¹ to L ¹⁸ represent divalent linking groups. The structures of L ¹¹ to L ¹⁸ are not particularly limited as long as a betaine structure can be introduced into the polymer side chain. The chemical formula weight of L ¹¹ to L ¹⁸ is preferably 14-2000, more preferably 14-200, even more preferably 14-100.
Divalent linking groups that can be used as L ¹¹ to L ¹⁸ can have, for example, the following structures.
an alkylene group having 1 to 16 carbon atoms, an aromatic group, an oxygen atom, a sulfur atom, an imino group (--N(R ^N )--), a carbonyl group, or a combination of two or more thereof;
In the present invention, R 3 ^N of “imino group (—N(R ^N )—)” is a hydrogen atom or a substituent. Substituents that can be taken as ^RN are not particularly limited, but include groups selected from substituents T described later, among which hydrogen atoms and alkyl groups are preferred.

The alkylene group having 1 to 16 carbon atoms that can be contained in L ¹¹ to L ¹⁸ may be linear or branched. The alkylene group that can be contained in L ¹¹ to L ¹⁸ preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms.
The aromatic group that can be contained in L ¹¹ to L ¹⁸ may be an aromatic hydrocarbon group or a heteroaromatic group having a heteroatom as a ring-constituting atom. Also, the aromatic group may be a condensed ring. Aromatic rings constituting aromatic groups that can be contained in L ¹¹ to L ¹⁸ include benzene ring, furan ring, thiophene ring, pyrrole ring, pyrazole ring, imidazole ring, triazole ring, pyridine ring, pyridazine ring and pyrimidine ring. , pyrazine ring, triazine ring, oxazole ring, thiazole ring, etc., and two or more (preferably two or three) of these rings may be condensed. Among them, the aromatic group that can be contained in ^L21 is preferably a phenylene group.

L ¹¹ , L ¹³ , L ¹⁵ and L ¹⁷ are an ester bond (-C(=O)O-) or an amide bond (-C(=O)NR ^N -, R ^N is the above ^RN in the imino group synonymous). These ester bonds and amide bonds are preferably derived from the (meth)acryloyloxy group and (meth)acrylamide group of the monomer, respectively. In the present invention, "(meth)acryloyl" includes both methacryloyl and acryloyl (the same applies to "(meth)acryl" and "(meth)acrylamide").
It is also preferred that L ¹¹ , L ¹³ , L ¹⁵ and L ¹⁷ have the above aromatic groups. In addition, L ¹¹ , L ¹³ , L ¹⁵ and L ¹⁷ preferably have an alkylene group, and preferably have an oxygen atom (-O-, an oxygen atom not forming an ester bond).
L ¹¹ , L ¹³ , L ¹⁵ and L ¹⁷ are a combination of an ester bond and an alkylene group, a combination of an amide bond and an alkylene group, a combination of an ester bond, an alkylene group and an oxygen atom, or an amide bond and an alkylene Combinations of radicals and oxygen atoms are preferred. In these cases, the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.
In the amide bond (-C(=O)NR ^N -) that L ¹¹ , L ¹³ , L ¹⁵ and L ¹⁷ may have, R ^N may have a betaine structure. For example, ^RN is an alkyl group, and this alkyl group can have a betaine structure in its substituent.
Further, in formulas (J-1), (J-2) and (J-3), in the amide bond that L ¹¹ , L ¹³ and L ¹⁵ may have, each R ^N of the amide bond is It can also be a form in which each of R ¹⁴ , R ¹⁹ and R ²⁴ is bound.

L ¹² , L ¹⁴ , L ¹⁶ and L ¹⁸ preferably have an alkylene group, may be a combination of an alkylene group and an oxygen atom, and are more preferably an alkylene group or an oxyalkylene group. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.

Preferable specific examples of the component (a) are shown below, but the above components in the present invention should not be construed as being limited to these.

The polymer constituting the binder component is a component having a salt structure of at least one of carboxylate, sulfonate, phosphate, phosphonate, nitrate and ammonium salt (hereinafter also referred to as component (b) .). This component (b) is a different component from the component (a).
The above salt structure may be contained in the main chain or in the side chain, but is preferably contained in the side chain. By including the component having the above salt structure, the content can be adjusted to increase the water solubility of the polymer to a desired level. In addition, it is thought that the interaction with the surface of the active material or the current collector is also enhanced, which can contribute to the improvement of binding properties.

Component (b) is preferably derived from compounds having (meth)acryloyl or (meth)acrylamide groups.
The chemical formula weight of the component (b) is preferably 60-60,000, more preferably 70-20,000. A form in which a crosslinked structure is formed by neutralization of a divalent or higher valent metal or a polyfunctional organic base is also preferred. In the present invention, "(meth)acryloyl" is a concept that includes both methacryloyl and acryloyl.
Component (b) is preferably a component having a salt structure of at least one of carboxylate, sulfonate and phosphate.

Usual cations or anions can be used as counterions for forming the salt structure. Examples of cations as counter ions include metal cations such as sodium ions, lithium ions, potassium ions, calcium ions, magnesium ions and zinc ions. It is also preferred to have cations derived from amines. Examples of such amines include polyvalent amines such as polyethyleneimine, monoalkylamines such as hexylamine, dialkylamines such as dibutylamine, trialkylamines such as triethylamine, alcohol amines such as ethanolamine, and aromatic rings such as benzylamine and dimethylaminopyridine. Polycyclic amines such as containing amines and diazabicycloundecene can be preferably used.
Examples of anions as counterions include, for example, halogen anions.
Two or more counterions may be used to form the salt structure. For example, it is also preferable to use together a metal cation and a cation derived from an amine (preferably a cation derived from a polyvalent amine such as polyethyleneimine).

The above polymer may have a structural component (bH) in which a hydrogen atom is bonded to the end of the structural component (b) without forming a salt structure. That is, when a polymer having the component (bH) is present with a neutralizing agent, part or all of the component (bH) forms a salt structure and exists as the component (b). The ratio of the molar amount (Z) of the component (b) to the total (Q) of the molar amount of the component (bH) and the component (b) (100 x Z/Q) is the degree of neutralization of the polymer. (mol%). The degree of neutralization of the polymer is preferably 30 mol % or more, more preferably 50 mol % or more, still more preferably 60 mol % or more, and particularly preferably 70 mol % or more. The degree of neutralization of the polymer may be 100 mol %, preferably 95 mol % or less, more preferably 90 mol % or less.
Examples of neutralizing agents include inorganic bases such as hydroxides, carbonates, and hydrogencarbonates of metals belonging to Group 1 of the periodic table, hydroxides and carbonates of metals belonging to Group 2 of the periodic table, and polyethylene. polyvalent amines such as imine; organic bases such as diazabicycloundecene, pyridine, triethylamine, benzylamine, pentylamine, octylamine, dibutylamine, ethanolamine and histidine; inorganic compounds such as hydrochloric acid, hydrogen bromide, sulfuric acid and nitric acid. organic acids such as acid, formic acid, acetic acid, oxalic acid, and citric acid; The neutralizing agent may be used singly or in combination of two or more, preferably in combination of two or more. Preferred neutralizing agents include lithium hydroxide, sodium hydroxide, polyethylenimine and diazabicycloundecene as sources of counterion cations, and hydrochloric acid as sources of counterion anions. .

Specific examples of the component (b) are shown below, but the component (b) in the present invention should not be construed as being limited thereto.

Salts of (meth)acrylic acid can be preferably used as the component (b).

The polymer constituting the binder component preferably has a component represented by the following formula (O-31) (hereinafter also referred to as component (c)). Component (c) represented by formula (O-31) is a component different from component (a), component (b), and component (bH).

In formula (O-31), R ³¹ to R ³³ each independently represent a hydrogen atom, a cyano group, a halogen atom or an alkyl group. The alkyl groups that can be taken as R ³¹ to R ³³ are synonymous with the alkyl groups that can be taken as R ¹¹ to R ¹³ in formula (J-1), and the preferred forms are also the same.

R ³⁴ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a phenyl group, an aliphatic cyclic group or a halogen atom.
The alkyl group having 1 to 12 carbon atoms that can be taken as R ³⁴ may be linear or branched. The number of carbon atoms in this alkyl group is preferably 1-6, more preferably 1-4.
The aliphatic ring group that can be taken as R ³⁴ is preferably a 5- or 6-membered ring. Moreover, it is preferably an aliphatic heterocyclic group. The ring-constituting heteroatom possessed by the aliphatic heterocyclic group is preferably an oxygen atom, a sulfur atom or a nitrogen atom, more preferably an oxygen atom.
R ³⁴ is more preferably a hydroxy group.

^Y21 represents an imino group or an oxygen atom.

L ⁴¹ represents an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, or a linking group combining these. However, when the side of L ⁴¹ that bonds to R ³⁴ is an alkylene group having 1 to 16 carbon atoms, R ³⁴ is a hydrogen atom, a hydroxy group, a phenyl group, an aliphatic cyclic group or a halogen atom (preferably a fluorine atom or a chlorine atom). The number of carbon atoms in the alkylene group having 1 to 16 carbon atoms is preferably 1 to 12, more preferably 1 to 10, still more preferably 1 to 8, and particularly preferably 1 to 6.
The chemical formula weight of L ⁴¹ is preferably 14-2000, more preferably 28-500, even more preferably 40-200.
The alkylene group having 1 to 16 carbon atoms that L ⁴¹ may have may be linear or branched. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms.

L ⁴¹ is an alkylene group having 1 to 16 carbon atoms, an alkyleneoxy group (the number of carbon atoms in the alkyleneoxy group is preferably 1 to 10, more preferably 2 to 6, and still more preferably 2 to 4), a polyalkyleneoxy group. (The number of repetitions (average number of repetitions) of the alkyleneoxy group is preferably 2 to 10, more preferably 2 to 5, more preferably 2 or 3; the number of carbon atoms in the alkyleneoxy group is preferably 1 to 10, and 2 to 6 more preferably 2 to 4) or an arylene group having 6 to 12 carbon atoms. Among them, an alkylene group having 1 to 16 carbon atoms is more preferable, an alkylene group having 1 to 12 carbon atoms is more preferable, an alkylene group having 1 to 10 carbon atoms is particularly preferable, and an alkylene group having 1 to 8 carbon atoms is more preferable. , is most preferably an alkylene group having 1 to 6 carbon atoms.

Component (c) preferably has a glass transition temperature (Tg) of 60° C. or lower, more preferably 40° C. or lower, even more preferably 20° C. or lower, and preferably 0° C. or lower. Especially preferred.
The Tg of the component (c) is the Tg of the polymer composed of the component (c) alone, and the Tg described in the table in POLYMER HANDBOOK fourth edition VI is adopted. The Tg of polymers not listed in the table above is determined experimentally. That is, a dry sample of the polymer is prepared and measured under the following conditions using a differential scanning calorimeter: X-DSC7000 (trade name, manufactured by SII Nanotechnology). The same sample is measured twice, and the result of the second measurement is adopted.
Atmosphere in measurement chamber: Nitrogen gas (50 mL/min)
Heating rate: 5°C/min Measurement start temperature: -80°C
Measurement end temperature: 250°C
Sample pan: Aluminum pan Mass of measurement sample: 5 mg
Calculation of Tg: Tg is calculated by rounding off the decimal point of the intermediate temperature between the falling start point and the falling end point on the DSC chart.
The Tg of the component (c) is preferably -45°C or higher.

Specific examples of the component (c) are shown below, but the component (c) in the present invention should not be construed as being limited thereto.

It is also preferable that the above polymer has, as the component (c), two or more hydroxyalkyl acrylate components having different chain lengths of alkylene groups.

Substituent T includes the following.
alkyl groups (preferably alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl etc.), cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), aryl groups (preferably having 6 to 26 carbon atoms aryl groups such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, more preferably A 5- or 6-membered heterocyclic group having at least one oxygen atom, sulfur atom, or nitrogen atom, including aromatic heterocyclic groups and aliphatic heterocyclic groups, such as a tetrahydropyran ring group , tetrahydrofuran ring group, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc.), alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, such as methoxy , ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), Heterocyclic oxy group (group in which -O- group is bonded to the above heterocyclic group), alkoxycarbonyl group (preferably alkoxycarbonyl group having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc.) , an aryloxycarbonyl group (preferably an aryloxycarbonyl group having 6 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), an amino group (preferably includes amino groups, alkylamino groups and arylamino groups having 0 to 20 carbon atoms, such as amino (—NH ₂ ), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino etc.), a sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, such as N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), an acyl group (an alkylcarbonyl group, an alkenylcarbonyl group, Acyl groups, including alkynylcarbonyl groups, arylcarbonyl groups and heterocyclic carbonyl groups, preferably having 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy groups (including alkylcarbonyloxy groups, alkenylcarbonyloxy groups, alkynylcarbonyloxy groups, arylcarbonyloxy groups, and heterocyclic carbonyloxy groups, preferably acyloxy groups having 1 to 20 carbon atoms, For example, acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), aryloxy groups (preferably carbon aryloyloxy group having a number of 7 to 23, such as benzoyloxy), carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, such as N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.) , an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, such as methylthio, ethylthio, isopropyl thio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclic thio groups (the above -S- group bonded to a heterocyclic group), alkylsulfonyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl group (preferably a arylsulfonyl group having 6 to 22, such as benzenesulfonyl), alkylsilyl group (preferably alkylsilyl group having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), An arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, such as triphenylsilyl), a phosphoryl group (preferably a phosphate group having 0 to 20 carbon atoms, such as —OP (=O )(R ^P ) ₂ ), a phosphonyl group (preferably a phosphonyl group having 0 to 20 carbon atoms, such as —P(=O)(R ^P ) ₂ ), a phosphinyl group (preferably having 0 to 20 carbon atoms is a phosphinyl group, such as —P(R ^P ) ₂ ), a sulfo group (sulfonic acid group), a carboxy group, a hydroxy group, a sulfanyl group, a cyano group, a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, atoms, etc.). R ^P is a hydrogen atom or a substituent (preferably a group selected from substituent T).
In addition, each of the groups exemplified for the substituent T may further have the above substituent T as a substituent.

The content of the constituent component (a) represented by formula (J-1) in the polymer that is the binder component is preferably 2 to 60% by mass, more preferably 3 to 25% by mass, and 4 to 20% by mass. % is more preferred, and 5 to 15% by mass is particularly preferred.
Further, when the polymer has a component (b) and/or a component (bH) separately from the component (a) represented by formula (J-1), the component (b ) and/or the total content of the constituent component (bH) is preferably 2 to 95% by mass, more preferably 3 to 70% by mass, even more preferably 5 to 60% by mass, and 5 to 30% by mass. Especially preferred. The total content of component (b) and/or component (bH) may be 6 to 95% by mass, 7 to 95% by mass, or 7 to 90% by mass. The ratio of the molar amount of component (b) to the total molar amount of component (b) and component (bH) is as described above for the degree of neutralization of the polymer.
Further, when the polymer has a component (c) represented by formula (O-31), the content of component (c) represented by formula (O-31) in the polymer is 2 to 90. % by mass is preferable, 5 to 90% by mass is more preferable, 10 to 90% by mass is even more preferable, 20 to 90% by mass is particularly preferable, and 40 to 85% by mass is particularly preferable. , 60 to 85% by mass.

The polymer, which is a binder component that constitutes the binder composition of the present invention, has properties that can follow repeated swelling and contraction of the active material and a desired result when it is assumed to be used in a non-aqueous electrolyte secondary battery. From the viewpoint of exhibiting adhesiveness and prolonging the cycle life, it is preferred that the electrolyte swells to some extent. For example, the swelling rate of the polymer with respect to a solvent (pseudo-electrolytic solution) obtained by mixing ethylene carbonate and ethyl methyl carbonate at a mass ratio of ethylene carbonate/ethyl methyl carbonate = 1/2 is 1% or more and less than 200%. is preferably 7% or more and less than 150%, more preferably 8% or more and less than 150%, and particularly preferably 10% or more and less than 150%. Here, when the polymer does not swell in the solvent, the swelling rate is 0%. The swelling rate is determined by the method described in Examples below.

The weight average molecular weight of the polymer is preferably 100,000 or more. When the weight-average molecular weight of the polymer is sufficiently large, the binding action of the polymer is enhanced, and the cycle life of the non-aqueous secondary battery using the binder composition containing the polymer is prolonged.

The weight average molecular weight is the weight average molecular weight converted to sodium polyacrylate by gel permeation chromatography (GPC), and can be determined under the following conditions.
Measuring instrument: HLC-8220GPC (trade name, manufactured by Tosoh Corporation)
Column: TOSOH TSKgel 5000PWXL (trade name, manufactured by Tosoh Corporation), TOSOH TSKgel G4000PWXL (trade name, manufactured by Tosoh Corporation), and TOSOH TSKgel G2500PWXL (trade name, manufactured by Tosoh Corporation) are connected.
Carrier: 200 mM sodium nitrate aqueous solution Measurement temperature: 40°C
Carrier flow rate: 1.0 ml/min
Sample concentration: 0.2%
Detector: RI (refractive index) detector

If the weight average molecular weight cannot be measured under the above measurement conditions because the polymer is crosslinked, etc., the weight average molecular weight is measured by static light scattering under the following conditions.
Measuring instrument: DLS-8000 (trade name, manufactured by Otsuka Electronics Co., Ltd.)
Measurement concentration: 0.25, 0.50, 0.75, 1.00mg/ml
Diluent: 0.1 M NaCl aqueous solution Laser wavelength: 633 nm
Pinhole: PH1=Open, PH2=Slit
Measurement angle: 60, 70, 80, 90, 100, 110, 120, 130 degrees Analysis method: Molecular weight was measured from Zimm square root plot. dn/dc required for analysis is actually measured with an Abbe refractometer.

The binder composition of the present invention may contain one of the above polymers alone or two or more of them.

The above polymer can be synthesized by combining monomers leading to each of the above constituents according to the purpose and subjecting them to addition polymerization in the presence of a catalyst (including a polymerization initiator, a chain transfer agent, etc.) if necessary. The method and conditions for addition polymerization are not particularly limited, and ordinary methods and conditions can be selected as appropriate.

The binder composition of the present invention preferably contains water in an amount of 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and particularly preferably 40% by mass or more. The binder composition of the present invention may contain water in an amount of 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more.
The content of the polymer in the binder composition of the present invention may be appropriately set depending on the purpose. For example, the polymer content in the binder composition can be 2 to 50% by mass, preferably 4 to 30% by mass, more preferably 6 to 20% by mass. In the binder composition of the present invention, the balance excluding the polymer is preferably composed of water, a neutralizing agent, and a water-soluble organic solvent, and the balance excluding the polymer is water and the neutralizing agent. is more preferred.

[Electrode composition]
The electrode composition of the present invention contains, in addition to the binder composition, an active material capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table. Conductivity aids and other additives may be added as necessary. The active material may be a positive electrode active material or a negative electrode active material. When the electrode composition contains a positive electrode active material, the electrode composition can be used as slurry for forming a positive electrode active material layer of a non-aqueous secondary battery. Moreover, when the composition for electrodes contains a negative electrode active material, the composition for electrodes can be used as slurry for forming a negative electrode active material layer. Although the above binder composition can be applied to both positive and negative electrode compositions, it is preferably used for negative electrodes, and particularly preferably used for negative electrode compositions having a silicon atom-containing active material.
The active material, conductive aid, and other additives are not particularly limited, and may be appropriately selected and used from those used in conventionally known non-aqueous secondary batteries according to the purpose.

(Positive electrode active material)
The positive electrode active material is preferably one capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above properties, and may be a transition metal oxide, an organic substance, an element such as sulfur that can be combined with Li, or a compound of sulfur and a metal.
Among them, it is preferable to use a transition metal oxide as ^the positive electrode active material. things are more preferred. In addition, the element M ^b (an element of group 1 (Ia) of the periodic table other than lithium, an element of group 2 (IIa) of the periodic table, Al, Ga, In, Ge, Sn, Pb, Sb) is added to the transition metal oxide. , Bi, Si, P or B) may be mixed. The mixing amount is preferably 0 to 30 mol % with respect to the amount (100 mol %) of the transition metal element ^Ma . More preferably, they are synthesized by mixing so that the molar ratio of Li/Ma is 0.3 to 2.2.
Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD ) lithium-containing transition metal halide phosphate compounds and (ME) lithium-containing transition metal silicate compounds.

(MA) Specific examples of transition metal oxides having a layered rocksalt structure include LiCoO ₂ (lithium cobalt oxide [LCO]), LiNi ₂ O ₂ (lithium nickel oxide), and LiNi _0.85 Co _0.10 Al _{0.85. 05O2} (lithium nickel cobalt _aluminum oxide [NCA]), _{LiNi1 /3Co1/ 3Mn1} / _{3O2 (} lithium nickel manganese cobaltate [NMC]) and _{LiNi0.5Mn0.5O2 (} lithium manganese nickelate).
(MB) Specific examples of transition metal oxides having a spinel structure include LiMn ₂ O ₄ (LMO), LiCoMnO ₄ , Li ₂ FeMn ₃ O ₈ , Li ₂ CuMn ₃ O ₈ , Li ₂ CrMn ₃ O ₈ and Li _{2NiMn3O8 . _}
Examples of (MC) lithium-containing transition metal phosphate compounds include olivine-type iron phosphates such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , and LiCoPO ₄ . and monoclinic Nasicon-type vanadium phosphates such as Li ₃ V ₂ (PO ₄ ) ₃ (lithium vanadium phosphate).
Examples of (MD) lithium-containing transition metal halogenated phosphate compounds include iron fluorophosphates such as Li ₂ FePO ₄ F, manganese fluorophosphates such as Li ₂ MnPO ₄ F, and Li ₂ CoPO ₄ F. and cobalt fluoride phosphates.
(ME) Lithium-containing transition metal silicate compounds include, for example, Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ and Li ₂ CoSiO ₄ .
In the present invention, transition metal oxides having a (MA) layered rocksalt structure are preferred, and LCO or NMC is more preferred.

Although the shape of the positive electrode active material is not particularly limited, it is preferably particulate. The average particle size (average particle size in terms of spheres) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 μm. An ordinary pulverizer or classifier may be used to reduce the positive electrode active material to a predetermined particle size. The positive electrode active material obtained by the calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent before use.

The said positive electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.
When the positive electrode active material layer is formed, the mass (mg) (basis weight) of the positive electrode active material per unit area (cm ² ) of the positive electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.

The content of the positive electrode active material in the electrode layer composition is not particularly limited. More preferably, 55 to 95% by mass is particularly preferable.

(Negative electrode active material)
The negative electrode active material is preferably capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above properties, carbonaceous materials, silicon-based materials, metal oxides, metal composite oxides, elemental lithium, lithium alloys, negative electrode active materials capable of forming an alloy with lithium. etc. Among them, a carbonaceous material or a silicon-based material is preferably used from the viewpoint of reliability.

A carbonaceous material used as a negative electrode active material is a material substantially composed of carbon. For example, carbon black such as petroleum pitch, graphite (natural graphite, artificial graphite such as vapor growth graphite, etc.), and carbonaceous materials obtained by baking various synthetic resins such as PAN (polyacrylonitrile) resin or furfuryl alcohol resin Materials can be mentioned. Furthermore, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor growth carbon fiber, dehydrated PVA (polyvinyl alcohol)-based carbon fiber, lignin carbon fiber, vitreous carbon fiber and activated carbon fiber. , mesophase microspheres, graphite whiskers and tabular graphite.

The metal oxide and metal composite oxide used as the negative electrode active material are not particularly limited as long as they are oxides capable of intercalating and deintercalating lithium, and amorphous oxides are preferred. Chalcogenites, which are reaction products with Group 16 elements, are also preferred. The term “amorphous” as used herein means a broad scattering band having an apex in the region of 20° to 40° in terms of 2θ value in an X-ray diffraction method using CuKα rays, and a crystalline diffraction line. may have
Among the compound group consisting of the above amorphous oxides and chalcogenides, amorphous oxides of metalloid elements and the above chalcogenides are more preferable, elements of groups 13 (IIIB) to 15 (VB) of the periodic table, Particularly preferred are oxides or chalcogenides composed of Al, Ga, Si, Sn, Ge, Pb, Sb and Bi alone or in combination of two or more thereof. Specific examples of preferred amorphous oxides and chalcogenides include Ga ₂ O ₃ , GeO, PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ and Sb _{2 . O4 , Sb2O8Bi2O3, Sb2O8Si2O3 , Sb2O5 , Bi2O3 , Bi2O4 , GeS} , _{PbS , PbS2 , Sb2S3 and Sb2 S5} is preferred.

The metal (composite) oxide and the chalcogenide preferably contain at least one of titanium and lithium as a constituent component from the viewpoint of high current density charge/discharge characteristics. Examples of lithium-containing metal composite oxides (lithium composite metal oxides) include composite oxides of lithium oxide and the above metal (composite) oxides or chalcogenides, more specifically Li ₂ SnO _{2 .} mentioned.

It is also preferable that the negative electrode active material contains titanium atoms. More specifically, TiNb ₂ O ₇ (niobium titanate [NTO]) and Li ₄ Ti ₅ O ₁₂ (lithium titanate [LTO]) have small volume fluctuations when lithium ions are absorbed and desorbed, and thus are suitable for rapid charging. It is preferable in that it has excellent discharge characteristics, suppresses deterioration of the electrode, and can improve the life of the lithium ion secondary battery.

The lithium alloy as the negative electrode active material is not particularly limited as long as it is an alloy normally used as a negative electrode active material for secondary batteries, and examples thereof include lithium aluminum alloys.

The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is commonly used as a negative electrode active material for secondary batteries. Such an active material expands and shrinks significantly due to charging and discharging, and the binding property of solid particles is lowered as described above. Examples of such active materials include negative electrode active materials having silicon atoms or tin atoms, metals such as Al and In, and negative electrode active materials having silicon atoms that enable higher battery capacity (silicon atom-containing active materials ) is preferable, and a silicon atom-containing active material having a silicon atom content of 40 mol % or more of all constituent atoms is more preferable.
In general, a negative electrode containing these negative electrode active materials (e.g., a Si negative electrode containing a silicon atom-containing active material, a Sn negative electrode containing an active material having a tin atom) is a carbon negative electrode (graphite, acetylene black, etc.) can occlude more Li ions than That is, the amount of Li ions stored per unit mass increases. Therefore, the battery capacity (energy density) can be increased. As a result, there is an advantage that the battery driving time can be lengthened.
Examples of active materials containing silicon atoms include silicon materials such as Si and SiOx (0<x≦1), and alloys containing titanium, vanadium, chromium, manganese, nickel, copper, or lanthanum (for example, LaSi ₂ , VSi ₂ ), or organized active materials (eg, LaSi ₂ /Si), and active materials containing silicon and tin atoms such as SnSiO ₃ and SnSiS ₃ . In addition, SiOx itself can be used as a negative electrode active material (semimetal oxide), and since Si is generated by the operation of the battery, it can be used as an active material (precursor material thereof) that can be alloyed with lithium. can be used.
Examples of negative electrode active materials containing tin atoms include Sn, SnO, SnO ₂ , SnS, SnS ₂ , active materials containing silicon atoms and tin atoms, and the like. Also included are composite oxides with lithium oxide, such as Li ₂ SnO ₂ .

Although the shape of the negative electrode active material is not particularly limited, it is preferably particulate. The average particle size of the negative electrode active material is preferably 0.1 to 60 μm. A conventional pulverizer or classifier is used to obtain a predetermined particle size. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a whirling jet mill, a sieve, or the like is preferably used. At the time of pulverization, wet pulverization in which water or an organic solvent such as methanol is allowed to coexist can also be performed. Classification is preferably carried out in order to obtain a desired particle size. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as desired. Both dry and wet classification can be used.

The negative electrode active materials may be used singly or in combination of two or more. Among them, a combination of a silicon atom-containing active material and a carbonaceous material is preferred, and a combination of SiOx (0<x≦1) and graphite is particularly preferred. When SiOx (0<x≦1) and graphite are combined, the mass ratio (SiOx/graphite) is preferably 2 or less, more preferably 1 or less, and still more preferably 0.5 or less.
When the negative electrode active material layer is formed, the mass (mg) (basis weight) of the negative electrode active material per unit area (cm ² ) of the negative electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.

The content of the negative electrode active material in the electrode layer composition is not particularly limited, and is preferably 10 to 98% by mass, more preferably 20 to 90% by mass based on 100% by mass of solid content.

The chemical formula of the compound obtained by the above firing method can be calculated by inductively coupled plasma (ICP) emission spectrometry as a measuring method, or from the difference in mass of the powder before and after firing as a simple method.

In the present invention, when the negative electrode active material layer is formed by charging the battery, ions of a metal belonging to Group 1 or Group 2 of the periodic table generated in the all-solid secondary battery are used instead of the negative electrode active material. can be used. A negative electrode active material layer can be formed by combining this ion with an electron and depositing it as a metal.

(Coating of active material)
The surfaces of the positive electrode active material and the negative electrode active material may be surface-coated with another metal oxide. Examples of surface coating agents include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si or Li. Specific examples include titanate spinel, tantalum- _based oxides, _niobium -based oxides, and lithium _niobate -based compounds. Specific examples include _Li4Ti5O12 , _Li2Ti2O5 , and _{LiTaO3 .} , _LiNbO3 , _{LiAlO2 , Li2ZrO3} , _{Li2WO4 , Li2TiO3 , Li2B4O7 , Li3PO4 , Li2MoO4 , Li3BO3 , LiBO2 , Li2CO 3} , Li ₂ SiO ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ and the like.
Moreover, the surface of the electrode containing the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus.
Furthermore, the surface of the particles of the positive electrode active material or the negative electrode active material may be surface-treated with actinic rays or an active gas (such as plasma) before and after the surface coating.

(Conductivity aid)
The electrode composition of the present invention can also contain a conductive aid, and it is particularly preferred that the silicon atom-containing active material as the negative electrode active material is used in combination with the conductive aid.
There are no particular restrictions on the conductive aid, and any commonly known conductive aid can be used. For example, electronic conductive materials such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black and furnace black, amorphous carbon such as needle coke, vapor grown carbon fiber or carbon nanotube. Carbon fibers such as carbon fibers such as graphene or fullerene may be used, metal powders such as copper and nickel, metal fibers may be used, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives may be used. may be used.
In the present invention, when an active material and a conductive aid are used in combination, among the above conductive aids, a conductive aid that does not cause insertion and release of Li during charging and discharging of the battery and does not function as an active material. and Therefore, among the conductive aids, those that can function as an active material in the active material layer during charging and discharging of the battery are classified as active materials rather than conductive aids. Whether or not it functions as an active material when the battery is charged/discharged is not univocally determined by the combination with the active material.

1 type may be used for a conductive support agent, and 2 or more types may be used for it.
The content of the conductive aid in the electrode layer composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on 100% by mass of the solid content.

The shape of the conductive aid is not particularly limited, but is preferably particulate. The median diameter D50 of the conductive aid is not particularly limited, and is preferably 0.01 to 50 μm, more preferably 0.02 to 10.0 μm.

(other additives)
The solid electrolyte composition of the present invention may optionally contain lithium salts, ionic liquids, thickeners, antifoaming agents, leveling agents, dehydrating agents, antioxidants, etc. as other components in addition to the above components. can be done. In addition, for chemically cross-linking the above polymer, a cross-linking agent (such as those that undergo a cross-linking reaction by radical polymerization, condensation polymerization, or ring-opening polymerization), and further a polymerization initiator (such as those that generate acid or radicals by heat or light). may contain.
Regarding the active materials, conductive aids, and other additives used in non-aqueous secondary batteries, for example, International Publication No. 2019/203334, Japanese Patent Application Laid-Open No. 2015-46389, etc. can be referred to.

The content of the active material in the electrode composition of the present invention can be adjusted to, for example, 50 to 99% by mass. Further, in the electrode composition of the present invention, the mass ratio of the content of the active material and the polymer (binder component) can be set to active material/polymer = 1/1 to 200/1. = 1/33 to 5/1 is more preferable.

[Electrode sheet]
The electrode sheet of the present invention has a layer (active material layer, ie, negative electrode active material layer or positive electrode active material layer) formed using the electrode composition of the present invention. The electrode sheet of the present invention may be an electrode sheet having an active material layer. ) It may be a sheet formed only of an active material layer. This electrode sheet is usually a sheet having a structure in which an active material layer is laminated on a current collector. The electrode sheet of the present invention may have other layers such as a protective layer (release sheet) and a coat layer.
The electrode sheet of the present invention can be suitably used as a material constituting a negative electrode active material layer or a positive electrode active material layer of a non-aqueous secondary battery.

[Manufacturing method of electrode sheet]
The electrode sheet of the present invention can be obtained by forming an active material layer using the electrode composition of the present invention. For example, a current collector or the like is used as a substrate, and the composition for an electrode of the present invention is applied thereon (may be via another layer) to form a coating film, which is dried to form a substrate. An electrode sheet having an active material layer (coated dry layer) thereon can be obtained.

[Non-aqueous secondary battery]
In the present invention, the non-aqueous secondary battery means all devices in which ions pass between the positive and negative electrodes through a non-aqueous medium due to charging and discharging, and energy is stored and released at the positive and negative electrodes. That is, it means to include both batteries and capacitors (lithium ion capacitors). From the viewpoint of energy storage capacity, the non-aqueous secondary battery of the present invention is preferably used for battery applications (not a capacitor).
A non-aqueous secondary battery of the present invention has a configuration including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. In an all-solid secondary battery using an inorganic solid electrolyte, the separator can be an inorganic solid electrolyte layer.
The positive electrode has a positive electrode current collector and a positive electrode active material layer in contact with the positive electrode current collector, and the negative electrode has a negative electrode current collector and a negative electrode active material layer in contact with the negative electrode current collector. In the non-aqueous secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention.

FIG. 1 is a schematic cross-sectional view showing a laminate structure of a general non-aqueous secondary battery 10 including working electrodes when operated as a battery. The non-aqueous secondary battery 10 has a laminated structure having, viewed from the negative electrode side, a negative electrode current collector 1, a negative electrode active material layer 2, a separator 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order. there is
When the non-aqueous secondary battery 10 is a non-aqueous electrolyte secondary battery, the space between the negative electrode active material layer and the positive electrode active material layer is filled with a non-aqueous electrolyte (not shown) and separated by the separator 3 . ing. In this case, the separator 3 has pores, and functions as a positive/negative separator that insulates the positive/negative electrodes while permeating the electrolytic solution and ions under normal battery usage conditions.
When the non-aqueous secondary battery 10 is an all-solid secondary battery, the solid electrolyte layer 3 separates the negative electrode active material layer and the positive electrode active material layer.
With such a structure, for example, in the case of a lithium ion secondary battery, during charging, electrons (e ⁻ ) are supplied to the negative electrode side through an external circuit, and at the same time lithium ions (Li ⁺ ) are released from the positive electrode through the electrolyte. It moves and accumulates at the negative electrode. On the other hand, during discharge, the lithium ions (Li ⁺ ) accumulated in the negative electrode are returned to the positive electrode side through the electrolyte or solid electrolyte layer, and electrons are supplied to the operating portion 6 . In the illustrated example, the working portion 6 employs a light bulb, which is lit by electrical discharge.
In the present invention, the negative electrode current collector 1 and the negative electrode active material layer 2 are collectively referred to as a negative electrode, and the positive electrode active material layer 4 and the positive electrode current collector 5 are collectively referred to as a positive electrode.

Materials, non-aqueous electrolytes, solid electrolytes, members, etc. used in the non-aqueous secondary battery of the present invention are particularly limited except that the binder composition or electrode composition of the present invention is used to form a specific layer. not. For these materials, members, etc., those used in ordinary non-aqueous secondary batteries can be appropriately applied. As for the method for producing the non-aqueous secondary battery of the present invention, the usual method for producing an electrode sheet is used, except that the binder composition or the electrode composition of the present invention is used to form a specific layer. It can be adopted as appropriate. For example, JP-A-2016-201308, JP-A-2005-108835, JP-A-2012-185938, etc. can be referred to as appropriate.
A preferred form of the non-aqueous electrolyte will be described in more detail.

(Electrolytes)
The electrolyte used for the non-aqueous electrolyte is preferably a salt of a metal ion belonging to Group 1 or Group 2 of the periodic table. The metal ion salt to be used is appropriately selected depending on the intended use of the non-aqueous electrolyte. Examples include lithium salts, potassium salts, sodium salts, calcium salts, and magnesium salts. When used in non-aqueous electrolyte secondary batteries, lithium salts are preferred from the viewpoint of output. When the non-aqueous electrolyte of the present invention is used as a non-aqueous electrolyte for a lithium ion secondary battery, a lithium salt may be selected as the metal ion salt. The lithium salt is preferably a lithium salt that is commonly used in the electrolyte of a non-aqueous electrolyte for lithium ion secondary batteries, such as those described below.

(L-1) Inorganic lithium salts: inorganic fluoride salts such as LiPF ₆ , LiBF ₄ , LiAsF ₆ and LiSbF ₆ , perhalogenates such as LiClO ₄ , LiBrO ₄ and LiIO ₄ , inorganic chloride salts such as LiAlCl ₄ etc

(L-2) Fluorine-containing organic lithium salts: Perfluoroalkanesulfonates such as LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiN(CF ₃ CF ₂ SO ₂ ) ₂ , LiN(FSO ₂ ) ₂ , perfluoroalkanesulfonylimide salts such as LiN _{( CF3SO2 )} ( _C4F9SO2 ), perfluoroalkanesulfonylmethide salts such as LiC( _{CF3SO2 ) 3} , Li _{[PF5 ( CF2CF2 CF3} ) _] , Li[ _PF4 ( _CF2CF2CF3 ) ₂ ], _{Li [ PF3 (} CF2CF2CF3 _{) 3 ] ,} Li _{[ PF5} (CF2CF2CF2CF3)], _{Perfluoroalkyl} fluorophosphates such _as Li[ _PF4 ( _{CF2CF2CF2CF3 ) 2} ], _Li [ _{PF3 ( CF2CF2CF2CF3} ) ₃ ] _, etc.

(L-3) Oxalatoborate salts: lithium bis(oxalato)borate, lithium difluorooxalatoborate, etc.

Among these, _LiPF6 , _LiBF4 , _LiAsF6 , LiSbF6, _LiClO4 , Li( _Rf1SO3 ), LiN( _Rf1SO2 ) ₂ , LiN( _FSO2 ) ₂ , and LiN( _{Rf1SO2 )} ( _Rf2SO2 ) are preferred, and lithium imide salts such as _LiPF6 , _LiBF4 , LiN( _Rf1SO2 ) ₂ , LiN( _FSO2 ) ₂ and LiN( _Rf1SO2 )( _Rf2SO2 ) are more preferred. Here, Rf1 and Rf2 each represent a perfluoroalkyl group.
In addition, the electrolyte used for a non-aqueous electrolyte may be used individually by 1 type, or may combine 2 or more types arbitrarily.

The salt concentration of the electrolyte in the non-aqueous electrolyte (preferably the ion of a metal belonging to Group 1 or Group 2 of the periodic table or a metal salt thereof) is appropriately selected depending on the purpose of use of the non-aqueous electrolyte, but generally is 10% by mass to 50% by mass, more preferably 15% by mass to 30% by mass, based on the total mass of the non-aqueous electrolyte. A molar concentration of 0.5M to 1.5M is preferable. When the concentration of ions is evaluated, it may be calculated by salt conversion with the suitably applied metal.

(Non-aqueous solvent)
The non-aqueous electrolyte of the present invention contains a non-aqueous solvent.
As the non-aqueous solvent used in the present invention, aprotic organic solvents are preferable, and aprotic organic solvents having 2 to 10 carbon atoms are particularly preferable.
Examples of such non-aqueous solvents include linear or cyclic carbonate compounds, lactone compounds, linear or cyclic ether compounds, ester compounds, nitrile compounds, amide compounds, oxazolidinone compounds, nitro compounds, linear or cyclic sulfones or sulfoxide compounds and phosphate esters.
A compound having an ether bond, a carbonyl bond, an ester bond or a carbonate bond is preferred. These compounds may have a substituent, such as the substituent T described above.

Non-aqueous solvents include, for example, ethylene carbonate, fluoroethylene carbonate, vinylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, γ-butyrolactone, γ-valerolactone, 1, 2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, propion Methyl acid, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N,N-dimethylformamide, N-methyl pyrrolidinone, N-methyloxazolidinone, N,N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethylsulfoxide or dimethylsulfoxyphosphoric acid; These may be used individually by 1 type, or may use 2 or more types together. Among them, at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and γ-butyrolactone is preferable, and in particular, high viscosity (high dielectric constant) such as ethylene carbonate or propylene carbonate. A combination of a solvent (eg dielectric constant ε≧30) and a low-viscosity solvent (eg viscosity ≦1 mPa·s) such as dimethyl carbonate, ethylmethyl carbonate or diethyl carbonate is more preferable. By using such a combination of mixed solvents, the dissociation property of the electrolyte salt and the mobility of ions are improved.
In addition, the non-aqueous solvent used in the present invention is not limited to these.

The non-aqueous secondary battery of the present invention can be used, for example, in notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, cordless phone slaves, pagers, handy terminals, mobile facsimiles, mobile copiers, mobile printers, and headphone stereos. , video movies, liquid crystal televisions, handy cleaners, portable CDs, minidiscs, electric shavers, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, memory cards, and other electronic devices. . In addition, for consumer use, it can be installed in automobiles, electric vehicles, motors, lighting equipment, toys, game devices, road conditioners, watches, strobes, cameras, medical devices (pacemakers, hearing aids, shoulder massagers, etc.). It can also be combined with a solar cell.

The present invention will be described in more detail below based on examples. In addition, this invention is not limited and interpreted by this. "Parts" and "%" representing compositions in the following examples are based on mass unless otherwise specified.

<Preparation of Binder Composition Containing Polymer B-1>
260.0 g of distilled water was added to a 1 L three-necked flask equipped with a reflux condenser and a gas inlet cock. After introducing nitrogen gas at a flow rate of 200 mL/min for 60 minutes, the temperature was raised to 75°C. Liquid prepared in a separate container (acrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 6.0 g, hydroxyethyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 48.0 g, 3-[[2-(methacryloyloxy) ethyl ] Dimethylammonio]propionate (manufactured by Tokyo Kasei Co., Ltd., a monomer that gives a repeating unit represented by the above formula a-3) 6.0 g, distilled water 80.0 g, VA-057 (trade name: FUJIFILM Wako Pure Chemical Industries, Ltd. A liquid obtained by stirring and mixing 0.46 g of product) was added dropwise over 1 hour. After completion of dropping, stirring was continued at 75° C. for 3 hours. After cooling in an ice bath, 5.6 g of a 48% sodium hydroxide aqueous solution (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added. Thereafter, 240.0 g of distilled water was added to obtain an aqueous solution of binder B-1. The solid content concentration was 10.0% and the weight average molecular weight was 243,000. The degree of neutralization of the polymer is 80 mol%.
The amount of monomer used (% by mass) in the table below is the ratio of each monomer when the amount of all monomers used is 100% by mass. In addition, in the column of the component (a), the code of the component itself ("a-1" etc.) is described, but the mass% indicates the amount of the monomer that leads to the component. is.

<Preparation of Binder Composition Containing Polymers B-2 to B-14>
A monomer leading to the component (a) shown in Table 1 (represented by the above formula a-1 or a-3), a neutralizing agent, another monomer (acrylic acid, methacrylic acid, 2-acrylamido-2-methyl Using propanesulfonic acid, N-(2-hydroxyethyl)acrylamide, 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, methoxypolyethylene glycol acrylate (molecular weight about 2000, 4-hydroxybutyl acrylate), Polymer B Aqueous solutions (binder compositions) containing polymers B-2 to B-14 as binder components were obtained in the same manner as in -1. All aqueous solutions had a solid concentration of 10.0%. The degree of neutralization of each polymer is 80 mol %.

The structures of polymers B-1 to B-14 are shown below.

(Measurement of weight average molecular weight)
The weight average molecular weights (Mw) of polymers B-1 to B-8, B-10, and B-12 to B-14 are weight average molecular weights converted to sodium polyacrylate by gel permeation chromatography (GPC). , are values measured under the following conditions.
Measuring instrument: HLC-8220GPC (trade name, manufactured by Tosoh Corporation)
Columns: TOSOH TSKgel 5000PWXL (trade name, manufactured by Tosoh Corporation), TOSOH TSKgel G4000PWXL (trade name, manufactured by Tosoh Corporation), and TOSOH TSKgel G2500PWXL (trade name, manufactured by Tosoh Corporation) were connected.
Carrier: 200 mM sodium nitrate aqueous solution Measurement temperature: 40°C
Carrier flow rate: 1.0 ml/min Sample concentration: 0.2%
Detector: RI (refractive index) detector

The weight average molecular weights (Mw) of polymers B-9 and B-11 were measured by static light scattering under the following conditions.
Measuring device: DLS-8000 (trade name, manufactured by Otsuka Electronics Co., Ltd.)
Measurement concentration: 0.25, 0.50, 0.75, 1.00mg/ml
Diluent: 0.1 M NaCl aqueous solution Laser wavelength: 633 nm
Pinhole: PH1=Open, PH2=Slit
Measurement angle: 60, 70, 80, 90, 100, 110, 120, 130 degrees Analysis method: Molecular weight was measured from Zimm square root plot. dn/dc required for analysis was actually measured with an Abbe refractometer.

(Determination of glass transition temperature)
The Tg's of the polymer components were determined by the method described above.

[Test Example 1] Evaluation of swelling ratio to simulated electrolytic solution 5 g of each binder composition prepared above was placed on a surface-hydrophobicized PET (NP75C, trade name, manufactured by Panac) sheet and dried at 50°C for 6 hours. After that, each binder film was peeled off from the hydrophobized PET. Each binder film obtained was dried at 150° C. in vacuum for 6 hours. 0.10 g of each binder film after drying was weighed into a glass bottle, and 1.90 g of a solvent (simulated electrolyte) mixed with ethylene carbonate/ethyl methyl carbonate = 1/2 by mass ratio was added thereto, and heated at 60°C for 24 hours. Heated for hours. After heating, each binder film was taken out and the mass (Ws) was measured. After drying each binder film in a vacuum at 150° C. for 5 hours, the weight (Wd) was measured again. The obtained Ws and Wd values were applied to the following formula to calculate the swelling rate. Table 1 shows the results.
Degree of swelling (%) = [(Ws-Wd) / Wd] × 100

[Test Example 2] Evaluation of solid particle dispersibility 0.30 g of acetylene black (trade name: Denka Black, manufactured by Denka, conductive aid) and 2.50 g of each binder aqueous solution were placed in a 60 mL ointment container (manufactured by Umano Kagaku Co., Ltd.). (solid content 0.25 g) was added, and dispersed for 10 minutes at 2000 rpm using a foaming mixer (manufactured by THINKY). 2.5 g of distilled water was added to the dispersed liquid, and dispersed for 3 minutes at 2000 rpm using a foaming mixer (manufactured by THINKY). 2.5 g of distilled water was added to the dispersed liquid, and dispersed for 3 minutes at 2000 rpm using a foaming mixer (manufactured by THINKY). 3.2 g of the resulting liquid was added to a 60 mL ointment container (manufactured by Umano Kagaku Co., Ltd.), 7.2 g of distilled water was added, and the mixture was dispersed at 2000 rpm for 3 minutes. 0.1 g of the resulting liquid and 14.5 g of water were added to a 30 mL sample bottle for dilution. The scattering intensity average particle size of the diluted solution was measured using ELSZ-1000S (trade name: manufactured by Otsuka Electronics Co., Ltd.). The above measurement was repeated 5 times, and the average value was evaluated based on the following evaluation ranks. Table 2 shows the results.
-Dispersibility evaluation rank-
6: Less than 1.9 µm 5: 1.9 µm or more and less than 2.2 µm 4: 2.2 µm or more and less than 2.7 µm 3: 2.7 µm or more and less than 3.3 µm 2: 3.3 µm or more and less than 4.0 µm 1: 4.0 μm or more

[Preparation of electrode sheet]
Silicon monoxide (particle size: 5 μm, manufactured by Osaka Titanium Co., Ltd.) 1.35 g, graphite (trade name: MAG-D, manufactured by Hitachi Chemical Co., Ltd.) 3.15 g, acetylene black ( Product name: Denka Black, manufactured by Denka Co., Ltd.), 2.50 g of each binder composition (solid content: 0.25 g), and distilled water of 1.6 g were added, and the mixture was stirred at 2000 rpm using a foaming mixer (manufactured by THINKY Co., Ltd.). for 10 minutes. 1.3 g of distilled water was added to the dispersed liquid, and the mixture was dispersed at 2000 rpm for 10 minutes using a foaming mixer (manufactured by THINKY).
The resulting composition for each electrode (negative electrode) (containing 27% silicon monoxide, 63% graphite, 5% acetylene black, and 5% binder) was applied onto a copper foil having a thickness of 20 μm with an applicator, and was applied at 80° C. for 1 hour. dried for an hour. Then, after pressurizing using a pressing machine, it was dried in vacuum at 150° C. for 6 hours to obtain each electrode (negative electrode) sheet having a negative electrode active material layer with a thickness of 25 μm.

[Test Example 3] Evaluation of Adhesiveness Adhesive tape was applied to the entire electrode sheet cut into a width of 10 mm and a length of 50 mm, and the average stress when peeled off in the length direction at an angle of 90° at 100 mm/min was measured. It was measured. The above measurement was repeated eight times, and the average value was evaluated based on the following evaluation ranks. Table 2 shows the results.
-Adhesion evaluation rank-
6: 0.6 N or more 5: 0.4 N or more and less than 0.6 N 4: 0.2 N or more and less than 0.4 N 3: 0.1 N or more and less than 0.2 N 2: 0.05 N or more and less than 0.1 N 1: Less than 0.05N

[Production of non-aqueous secondary battery (2032 type coin battery)]
Each of the above electrode sheets was cut into a disk shape with a diameter of 13.0 mm and used as a negative electrode. Lithium foil (thickness 50 μm, 14.5 mm φ), polypropylene separator (thickness 25 μm, 16.0 mm φ), stacked in this order 1M LiPF ₆ ethylene carbonate/ethyl methyl carbonate (volume ratio 1:2) electrolyte solution on 200 μL separator soaked in 200 μL of the electrolytic solution was further added on the separator, and the negative electrode was stacked so that the active material layer surface was in contact with the separator. After that, the 2032 type coin case was crimped to prepare each coin battery (laminate consisting of Li foil-separator-negative electrode active material layer-copper foil).

[Test Example 4] Evaluation of resistance The discharge capacity retention rate of each coin battery was measured using a charge/discharge evaluation device: TOSCAT-3000 (trade name, manufactured by Toyo System Co., Ltd.). The battery was charged at a C rate of 0.2C (the rate at which the battery is fully charged in 5 hours) until the battery voltage reached 0.02V. Discharge was performed at a C rate of 0.2C until the battery voltage reached 1.5V. Each coin battery was initialized by repeating 3 cycles of charging and discharging, with one charging and one discharging as one charging and discharging cycle. Note that since the cell is a negative half cell, the voltage drops during charging and rises during discharging.
After initialization, the battery was discharged at a C rate of 0.2C until the battery voltage reached 0.02V, and discharged at 2C until it reached 1.5V. The discharge capacity at this time was compared with the discharge capacity (discharge capacity retention rate) when the discharge capacity at the 3rd cycle at the time of initialization was taken as 100%, and the resistance was evaluated by applying the following evaluation rank. A smaller discharge capacity retention rate indicates a higher resistance. Table 2 shows the results.
-Evaluation rank of discharge capacity retention rate (resistance)-
6: 96% or more 5: 94% or more and less than 96% 4: 92% or more and less than 94% 3: 87% or more and less than 92% 2: 80% or more and less than 87% 1: less than 80%

[Test Example 5] Evaluation of Cycle Characteristics The discharge capacity retention rate of each coin battery was measured with a charge/discharge evaluation device: TOSCAT-3000 (trade name, manufactured by Toyo System Co., Ltd.). The battery was charged at a C rate of 0.2C (the rate at which the battery is fully charged in 5 hours) until the battery voltage reached 0.02V. Discharge was performed at a C rate of 0.2C until the battery voltage reached 1.5V. Each coin battery was initialized by repeating 3 cycles of charging and discharging, with one charging and one discharging as one charging and discharging cycle.
After initialization, charging was performed at 0.5C until reaching 0.02V. Discharge was performed at 0.5C until reaching 1.5V. Cycle characteristics were evaluated by repeating 50 charge/discharge cycles, with one charge/discharge cycle being defined as one charge/discharge cycle. When the discharge capacity (initial discharge capacity) at the first cycle after initialization is 100%, the discharge capacity at the 50th cycle (discharge capacity retention rate) discharge capacity relative to the initial discharge capacity) is measured and applied to the following evaluation rank Cycle properties were evaluated. Table 2 shows the results.
-Evaluation rank of discharge capacity retention rate (cycle characteristics)-
6: 92% or more 5: 87% or more and less than 92% 4: 80% or more and less than 87% 3: 70% or more and less than 80% 2: 50% or more and less than 70% 1: less than 50%

[Comparative Examples 1 and 2]
As a binder component, in Comparative Example 1, the polymer BC-1 (methacrylic acid/ethyl acrylate/1,6-hexanediol acrylate copolymer) described in Example 1 of JP-A-2015-18776 was used. In the polymer BC-2 described in Production Example 3 of JP-A-2018-6334 (acrylamide/N-methylolacrylamide/acrylamide t-butylsulfonic acid/sodium methacrylsulfonate/acrylic acid/ethyl acrylate/acrylonitrile copolymer ) was used to prepare a binder composition (solid content concentration 10%), and the coin batteries BC-1 and BC-2 were prepared in the same manner as described above. evaluated. Table 2 shows the results.

Each electrode sheet using polymers BC-1 and BC-2, which have an acidic group but do not have a component containing the betaine structure defined in the present invention in the polymer side chain, as a binder for the negative electrode active material layer. However, the dispersibility of solid particles was low, resulting in a battery with high resistance and poor cycle characteristics. In other words, all of the dispersibility, binding property, battery resistance and cycle characteristics of solid particles could not be brought to a satisfactory level.
On the other hand, each of the electrode sheets using polymers B-1 to B-14 having a constituent component containing a betaine structure defined in the present invention as a binder for the negative electrode active material layer has good dispersibility and binding properties for solid particles. It was found to be excellent, the resistance of the resulting battery was sufficiently low, and the cycle life was sufficiently prolonged.

REFERENCE SIGNS LIST 10 Nonaqueous electrolyte secondary battery 1 Negative electrode current collector 2 Negative electrode active material layer 3 Separator 4 Positive electrode active material layer 5 Positive electrode current collector 6 Operating part (bulb)

Claims (13)

A binder composition for a non-aqueous secondary battery, comprising a binder composed of a polymer having a component containing a betaine structure. 2. The non-aqueous secondary battery according to claim 1, wherein said polymer has a component having a salt structure of at least one of carboxylate, sulfonate, phosphate, phosphonate, nitrate and ammonium salt. binder composition. 3. The nonionic salt structure of claim 2, wherein the salt structure is at least one of carboxylate, sulfonate, phosphate, phosphonate, and nitrate, and wherein the salt structure has a counterion derived from a polyvalent amine. A binder composition for water secondary batteries. 4. Any one of claims 1 to 3, wherein the polymer has a swelling rate of 1% or more and less than 200% in a solvent obtained by mixing ethylene carbonate and ethyl methyl carbonate at a mass ratio of ethylene carbonate/ethyl methyl carbonate=1/2. 2. The binder composition for non-aqueous secondary batteries according to 1 or 2 above. The binder composition for non-aqueous secondary batteries according to any one of claims 1 to 4, wherein the polymer has a component represented by the following formula (O-31).

In the formula, R ³¹ to R ³³ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group having 1 to 24 carbon atoms.
R ³⁴ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a phenyl group, an aliphatic cyclic group or a halogen atom.
^Y21 represents an imino group or an oxygen atom.
L ⁴¹ represents an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, or a linking group combining these. However, when the side of L ⁴¹ that bonds to R ³⁴ is an alkylene group having 1 to 16 carbon atoms, R ³⁴ represents a hydrogen atom, a hydroxy group, a phenyl group, an aliphatic cyclic group or a halogen atom. 6. The binder composition for non-aqueous secondary batteries according to claim 5, wherein the component represented by formula (O-31) contains a component having a glass transition temperature of 60° C. or lower. The binder composition for non-aqueous secondary batteries according to any one of claims 1 to 6, wherein the polymer has a weight average molecular weight of 100,000 or more. The binder composition for non-aqueous secondary batteries according to any one of claims 1 to 7, wherein the water content in the binder composition is 10% by mass or more. The binder composition for a non-aqueous secondary battery according to any one of claims 1 to 8 and an electrode active material capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table A composition for an electrode comprising: An electrode sheet having a layer composed of the electrode composition according to claim 9 . 10. A non-aqueous secondary battery having a positive electrode active material layer, a separator, and a negative electrode active material layer in this order, wherein at least one layer of the positive electrode active material layer and the negative electrode active material layer is the A non-aqueous secondary battery, which is a layer composed of an electrode composition. A method for producing an electrode sheet, comprising the step of forming a film using the electrode composition according to claim 9 . A method for manufacturing a non-aqueous secondary battery, comprising incorporating the electrode sheet obtained by the manufacturing method according to claim 12 into an electrode of the non-aqueous secondary battery.

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