JP2007299738A - Binder resin composition for nonaqueous electrolyte system energy device electrode, nonaqueous electrolyte system energy device electrode using the same, and nonaqueous electrolyte system energy device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder resin composition of a nonaqueous electrolyte system energy device with excellent adhesiveness to a collector of an electrode, especially one of an anode, as well as an anti-swelling property against electrolyte solution, and that, with the electrode with excellent elasticity and flexibility, and an electrode for the nonaqueous electrolyte system energy device with a large capacity and a small capacity deterioration at charge/discharge cycles with the use of the binder resin composition. <P>SOLUTION: The binder resin composition for a nonaqueous electrolyte system energy device electrode made by including a nitrile system polymer containing 80% by mass of repeating units derived from a nitrile group-containing monomer, and an α-olefin-α,β-unsaturated carboxylic acid copolymer containing a repeating unit derived from α-olefin and a repeating unit derived from α,β-unsaturated carboxylic acid, and the electrode of the nonaqueous electrolyte system energy device using the same, as well as the nonaqueous electrolyte system energy device are structured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a binder resin composition for a non-aqueous electrolyte-based energy device electrode, a non-aqueous electrolyte-based energy device electrode using the same, and a non-aqueous electrolyte-based energy device.

  2. Description of the Related Art Lithium ion secondary batteries, which are non-aqueous electrolyte energy devices having a high energy density, are widely used as power sources for portable information terminals such as notebook personal computers, mobile phones, and PDAs.

  In this lithium ion secondary battery (hereinafter referred to as a lithium battery), as a negative electrode active material, a carbon material having a multilayer structure capable of inserting lithium ions between layers (forming a lithium intercalation compound) and releasing is used. . In addition, lithium-containing metal composite oxide is mainly used as the positive electrode active material.

  A lithium battery electrode is prepared by kneading these active materials, a binder resin composition and a solvent (N-methyl-2-pyrrolidone, water, etc.) to prepare a slurry, and then using a current collector with a transfer roll or the like. It is applied to one or both sides of a certain metal foil, dried by removing the solvent to form a mixture layer, and then compression molded with a roll press or the like.

As the binder resin composition, polyvinylidene fluoride (hereinafter referred to as PVDF) is frequently used.
However, since PVDF has poor adhesion to the current collector (copper foil) of the negative electrode, when producing a negative electrode using PVDF, it is necessary to ensure the adhesion at the interface between the mixture layer and the current collector. Therefore, a large amount of PVDF must be blended with the negative electrode active material, which is a factor that hinders the increase in capacity of lithium batteries.

  In addition, PVDF does not necessarily have sufficient swell resistance to lithium battery electrolytes (liquids that mediate the exchange of lithium ions between the positive and negative electrodes associated with charge / discharge). When PVDF swells, the interface between the mixture layer and the current collector and the contact between the active materials in the mixture layer become loose. For this reason, when the conductive network of the electrode gradually collapses and the lithium battery repeats the charge / discharge cycle, it is a cause of a decrease in capacity over time.

As a solution to these problems, Patent Document 1 discloses a (meth) acrylonitrile-based polymer having a glass transition temperature higher than 0 ° C., and a rubber component that imparts flexibility and flexibility to the electrode (with a glass transition temperature of − A binder resin composition blended with a non-vinylidene fluoride polymer having good solubility in N-methyl-2-pyrrolidone at 80 to 0 ° C. is disclosed.
However, the rubber component tends to cover the surface of the active material, and there is a concern that the charge / discharge reaction of the battery is likely to be hindered.

On the other hand, Patent Document 2 proposes a binder resin composition in which a (meth) acrylonitrile-based polymer and a vinylidene fluoride-based polymer are blended, but the (meth) acrylonitrile-based polymer has a nitrile group. Therefore, it is difficult to obtain sufficient swelling resistance against the electrolytic solution.
Further, like Patent Document 1, there is a problem that the surface of the active material is easily covered and the charge / discharge reaction of the battery is easily inhibited.

JP 2003-282061 A JP 2003-317722 A

An object of the present invention is to provide a binder resin composition for an energy device electrode of a non-aqueous electrolyte system that has excellent adhesion to the current collector of the electrode and resistance to swelling with respect to the electrolytic solution, and also has good flexibility and flexibility of the electrode. It is in providing a thing (henceforth a binder resin composition).
Another object of the present invention is to provide an electrode for a non-aqueous electrolyte-based energy device that is excellent in charge / discharge characteristics with a high capacity and a small capacity drop in a charge / discharge cycle by using the binder resin composition. It is another object of the present invention to provide a non-aqueous electrolyte-based energy device, in particular, a lithium battery electrode and a lithium battery.

  As a result of extensive research, the present inventors have found that a nitrile polymer having a high nitrile group content, an α-olefin and an α, β-unsaturated carboxylic acid that supplement the flexibility and flexibility of the electrode. By using a polymer blend as a binder resin composition for non-aqueous electrolyte based energy device electrodes, it has excellent swelling resistance to the electrolyte and adhesion to the current collector of the electrode, and flexibility of the electrode. -It discovered that a flexibility became favorable and came to complete this invention.

That is, the present invention includes a nitrile polymer containing 80% by mass or more of a repeating unit derived from a nitrile group-containing monomer and a repeating unit derived from an α-olefin and a repeating unit derived from an α, β-unsaturated carboxylic acid. The present invention relates to a binder resin composition for non-aqueous electrolyte-based energy device electrodes comprising an α-olefin-α, β-unsaturated carboxylic acid copolymer.
Moreover, this invention relates to the binder resin composition for non-aqueous electrolyte type energy device electrodes whose said nitrile group containing monomer is acrylonitrile.

  In the present invention, the nitrile polymer may be a repeating unit derived from a nitrile group-containing monomer, a repeating unit derived from a carboxyl group-containing monomer, and / or the following general formula (I):

（式中、Ｒ₁はＨ又はＣＨ₃、Ｒ₂はＨ又は１価の炭化水素基、ｎは１〜５０の整数である）
で表される単量体由来の繰り返し単位とを含むことを特徴とする非水電解液系エネルギーデバイス電極用バインダ樹脂組成物に関する。

(Wherein R ₁ is H or CH ₃ , R ₂ is H or a monovalent hydrocarbon group, and n is an integer of 1 to 50)
The binder resin composition for non-aqueous-electrolyte-type energy device electrodes characterized by including the repeating unit derived from the monomer represented by these.

Moreover, this invention relates to the binder resin composition for non-aqueous electrolyte type energy device electrodes whose said carboxyl group-containing monomer is acrylic acid.
Moreover, this invention relates to the binder resin composition for non-aqueous electrolyte system energy device electrodes whose monomer represented by the said general formula (I) is methoxytriethyleneglycol acrylate.
In addition, the present invention provides that the repeating unit derived from the carboxyl group-containing monomer is 0.01 to 0.2 mol and / or the general formula (1) with respect to 1 mol of the repeating unit derived from the nitrile group-containing monomer. It is related with the binder resin composition for nonaqueous electrolyte system energy device electrodes whose repeating unit derived from the monomer represented by I) is 0.001-0.2 mol.

The present invention also relates to a binder resin composition for non-aqueous electrolyte energy device electrodes, wherein the α-olefin is ethylene and the α, β-unsaturated carboxylic acid is acrylic acid.
In the present invention, the α-olefin-α, β-unsaturated carboxylic acid copolymer has a molecular weight corresponding to a melt flow rate (ASTM D 1238) of 5 to 150 g / 10 min and an acid value of 50. It is related with the binder resin composition for non-aqueous electrolyte system energy device electrodes which are -250KOHmg / g.
The present invention also provides an organic solvent containing a nitrogen-containing solvent, the nitrile copolymer dissolved in the organic solvent, and the α-olefin-α, β-unsaturated carboxylic acid dispersed in the organic solvent. The present invention relates to a binder resin composition for non-aqueous electrolyte-based energy device electrodes, which contains an acid copolymer.

The present invention also includes a current collector and a mixture layer provided on at least one surface of the current collector, wherein the mixture layer includes an active material and an optional conductive filler. The present invention relates to a non-aqueous electrolyte system energy device electrode comprising a binder resin composition for an electrolyte system energy device electrode.
The present invention also relates to a nonaqueous electrolytic solution energy device including a nonaqueous electrolytic solution energy device electrode.
Furthermore, this invention relates to the non-aqueous electrolyte type energy device whose non-aqueous electrolyte type energy device is a lithium battery.

  The binder resin composition of the present invention comprises a nitrile polymer having a high nitrile group content and excellent adhesion to the current collector and swelling resistance to the electrolyte, and α- which supplements the flexibility and flexibility of the electrode. Because it is made of a blend containing an olefin and a copolymer of α, β-unsaturated carboxylic acid, it has excellent adhesion to the current collector of the electrode and resistance to swelling with respect to the electrolyte, and flexibility of the electrode. -Good flexibility. For this reason, a lithium battery that is a non-aqueous electrolyte system energy device using a non-aqueous electrolyte system energy device electrode produced using the binder resin composition of the present invention has a high capacity and is in a charge / discharge cycle. The capacity drop is small.

(1) Binder resin composition for non-aqueous electrolyte system energy device The binder resin composition for non-aqueous electrolyte system energy device of the present invention is a nitrile system containing 80% by mass or more of a repeating unit derived from a nitrile group-containing monomer. It contains a polymer and an α-olefin-α, β-unsaturated carboxylic acid copolymer.

(1-1) Nitrile Polymer The nitrile polymer in the present invention includes all repeating units derived from a nitrile group-containing monomer from the viewpoint of swelling resistance to an electrolytic solution. As long as it contains 80% by mass or more with respect to 100% by mass of the repeating unit, there is no particular limitation, including homopolymers of nitrile group-containing monomers and other monomers derived at a rate of less than 20% by mass. The copolymer containing the repeating unit of these is mentioned. For example, when the mass of all repeating units contained in the nitrile polymer is 100, the mass ratio of the repeating unit derived from the nitrile group-containing monomer / the repeating unit derived from another monomer is 80/20 to 100. / 0, preferably 85/15 to 99/1, more preferably 90/10 to 95/5.

(1-1-1) Nitrile group-containing monomer The nitrile group-containing monomer in the present invention is not particularly limited. For example, an acrylic nitrile group-containing monomer such as acrylonitrile and methacrylonitrile, Examples thereof include cyan nitrile group-containing monomers such as α-cyanoacrylate and dicyanovinylidene, and fumaric nitrile group-containing monomers such as fumaronitrile. Among these, acrylonitrile is preferable from the viewpoint of ease of polymerization, cost performance, flexibility and flexibility of the electrode, and the like.

  These nitrile group-containing monomers are used alone or in combination of two or more. When acrylonitrile and methacrylonitrile are used as the nitrile group-containing monomer of the present invention, acrylonitrile is, for example, 5 to 95% by mass, preferably 50 to 95% with respect to the total amount of the nitrile group-containing monomer. It is suitable to contain the mass%.

(1-1-2) Other monomer The other monomer in the present invention is not particularly limited as long as it is a monomer not containing a nitrile group. For example, methyl (meth) acrylate, ethyl ( Short chain (preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms) (meth) acrylates such as meth) acrylate and propyl (meth) acrylate, vinyl chloride, vinyl bromide, vinylidene chloride, etc. Vinyl halides, maleic imide, phenylmaleimide, (meth) acrylamide, styrene, α-methylstyrene, vinyl acetate, sodium (meth) allylsulfonate, sodium (meth) allyloxybenzenesulfonate, sodium styrenesulfonate , Monomers such as 2-acrylamido-2-methylpropanesulfonic acid and salts thereof.
In particular, as the other monomer in the present invention, a carboxyl group-containing monomer not containing a nitrile group, a monomer represented by the following general formula (I), and the like are preferably used.

（式中、Ｒ₁はＨ又はＣＨ₃、Ｒ₂は、Ｈ又は１価の炭化水素基、ｎは１〜５０の整数である）
これらの中では、電極の集電体との接着性の向上等の点でカルボキシル基含有単量体が好ましく、電極の柔軟性・可とう性の向上等の点から前記一般式（Ｉ）で表される単量体が好ましい。これらの他の単量体は、単独又は二種類以上組み合わせて用いることができる。他の単量体として上記カルボキシル基含有単量体及び式（Ｉ）で表される単量体を組み合わせて使用するときは、例えば、他の単量体由来の繰り返し単位全体の質量を１００とする場合、カルボキシル基含有単量体由来の繰り返し単位／式（Ｉ）で表される単量体由来の繰り返し単位の質量比は、９９／１〜１／９９、好ましくは、８０／２０〜２０／８０、より好ましくは、５０／５０であることが適当である。

(Wherein R ₁ is H or CH ₃ , R ₂ is H or a monovalent hydrocarbon group, and n is an integer of 1 to 50)
Among these, a carboxyl group-containing monomer is preferable from the viewpoint of improving the adhesion of the electrode to the current collector, and the general formula (I) from the viewpoint of improving the flexibility and flexibility of the electrode. The monomer represented is preferred. These other monomers can be used alone or in combination of two or more. When the above carboxyl group-containing monomer and the monomer represented by the formula (I) are used in combination as the other monomer, for example, the mass of the entire repeating unit derived from the other monomer is 100. In this case, the mass ratio of the repeating unit derived from the carboxyl group-containing monomer / the repeating unit derived from the monomer represented by formula (I) is 99/1 to 1/99, preferably 80/20 to 20 / 80, more preferably 50/50 is appropriate.

  The carboxyl group-containing monomer in the present invention is not particularly limited as long as it does not contain a nitrile group, but examples thereof include acrylic carboxyl group-containing monomers such as acrylic acid and methacrylic acid, and crotonic acid. Croton carboxyl group-containing monomers, maleic carboxyl group-containing monomers such as maleic acid and its anhydride, itaconic carboxyl group-containing monomers such as itaconic acid and its anhydride, citraconic acid and its Examples include citraconic carboxyl group-containing monomers such as anhydrides.

  Among these, acrylic acid is preferable from the viewpoints of ease of polymerization, cost performance, flexibility and flexibility of the electrode, and the like. These carboxyl group-containing monomers can be used alone or in combination of two or more. When acrylic acid and methacrylic acid are used as the carboxyl group-containing monomer of the present invention, acrylic acid is, for example, 5 to 95% by mass, preferably 50 to 50% with respect to the total amount of the carboxyl group-containing monomer. It is appropriate to contain 95% by mass.

The monomer represented by the general formula (I) in the present invention is not particularly limited as long as it does not contain a nitrile group and a carboxyl group.
N in the general formula (I) is an integer of 1 to 50, preferably 2 to 30, and more preferably 2 to 10. R ₂ is a monovalent hydrocarbon group that does not contain H or a nitrile group and a carboxyl group, for example, 1 to 50 carbon atoms, preferably 1 to 25 carbon atoms, more preferably 1 to 12 carbon atoms. A valent hydrocarbon group is suitable. When the number of carbon atoms is 50 or less, sufficient swelling resistance to the electrolytic solution can be obtained.

Here, as the hydrocarbon group, for example, an alkyl group and a phenyl group are suitable. R ₂ is particularly preferably an alkyl group having 1 to 12 carbon atoms or a phenyl group. This alkyl group may be linear or branched. Further, this alkyl group or phenyl group may be partially substituted with halogen such as fluorine, chlorine, bromine or iodine, nitrogen, phosphorus, aromatic ring, C3-C10 cycloalkane or the like.

  Specifically, for example, commercially available ethoxydiethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate EC-A), methoxytriethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate MTG-) A, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AM-30G), methoxypoly (n = 9) ethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate 130-A, Shin-Nakamura Chemical) Manufactured by Kogyo Co., Ltd., trade name: NK ester AM-90G), methoxypoly (n = 13) ethylene glycol acrylate (trade name: NK ester AM-130G), methoxypoly (n = 23) ethylene glycol acrylate (Shin Nakamura Chemical Co., Ltd.) Product name: NK ester AM-230 ), Octoxypoly (n = 18) ethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester A-OC-18E), phenoxydiethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate P) -200A, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AMP-20GY), phenoxypoly (n = 6) ethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AMP-60G) ), Nonylphenol EO adduct (n = 4) acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate NP-4EA), nonylphenol EO adduct (n = 8) acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name) : Light acrylate NP-8EA), methoxydiethylene glycol Tacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester MC, Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester M-20G), methoxytriethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name) : Light ester MTG), Methoxypoly (n = 9) ethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light ester 130MA, Shin-Nakamura Chemical Co., Ltd., trade name: NK ester M-90G), Methoxypoly (N = 23) ethylene glycol methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester M-230G), methoxypoly (n = 30) ethylene glycol methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light ester) 041MA).

Among these, methoxytriethylene glycol acrylate (R _{1 in the} general formula (I) is H, R ₂ is CH ₃ , and n is 3) is more preferable from the viewpoint of reactivity when copolymerized with acrylonitrile. . These monomers represented by the general formula (I) can be used alone or in combination of two or more.

(1-1-3) Content of each monomer repeating unit The repeating unit derived from a nitrile group-containing monomer, the repeating unit derived from a carboxyl group-containing monomer, and the general formula (I) The molar ratio with the repeating unit derived from the monomer is, for example, when there is a repeating unit derived from the carboxyl group-containing monomer with respect to 1 mol of the repeating unit derived from the nitrile group-containing monomer. 0.01-0.2 mol, preferably 0.02-0.1, more preferably 0.03-0.06 mol, repeating from the monomer represented by the general formula (I) When a unit is present, this unit is 0.001 to 0.2 mol, preferably 0.003 to 0.05 mol, more preferably 0.005 to 0.02 mol.

  If the repeating unit derived from the carboxyl group-containing monomer is 0.01 to 0.2 mol and the repeating unit derived from the monomer represented by the formula (I) is 0.001 to 0.2 mol, the electrolyte solution In the state where the swelling resistance against the current is maintained, the adhesion to the current collector can be improved, and the flexibility and flexibility of the electrode can be improved.

(1-2) α-Olefin-α, β-Unsaturated Carboxylic Acid Copolymer The α-olefin-α, β-unsaturated carboxylic acid copolymer in the present invention comprises a repeating unit derived from an α-olefin, α, If it is a copolymer containing the repeating unit derived from (beta) -unsaturated carboxylic acid, Comprising: It differs from the said nitrile polymer, there will be no restriction | limiting in particular. Examples of the α-olefin include α-olefins having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms such as ethylene and propylene. Examples of the α, β-unsaturated carboxylic acid include acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid, maleic anhydride and the like. Examples of the α-olefin-α, β-unsaturated carboxylic acid copolymer in the present invention include an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer.
Among α-olefin-α, β-unsaturated carboxylic acid copolymers, handling properties such as uniform compoundability in binder resin or mixture slurry and stability over time after compounding, resistance to electrolyte Ethylene-acrylic, in which α-olefin is ethylene and α, β-unsaturated carboxylic acid is acrylic acid, for example, in that it is excellent in electrolyte resistance) and contributes to the extension of the life of lithium secondary batteries. An acid copolymer is preferred. These α-olefin-α, β-unsaturated carboxylic acid copolymers are used alone or in combination of two or more.

The mass ratio of the repeating unit derived from α-olefin and the repeating unit derived from α, β-unsaturated carboxylic acid contained in the α-olefin-α, β-unsaturated carboxylic acid copolymer is 90/10 to 10 / 90, preferably 80/20 to 20/80, more preferably 50/50 is appropriate. The total amount of the repeating unit derived from α-olefin and the repeating unit derived from α, β-unsaturated carboxylic acid is 100% by mass of all repeating units contained in the α-olefin-α, β-unsaturated carboxylic acid copolymer. On the other hand, it is preferably 80% by mass or more, more preferably 90% by mass or more. The α-olefin-α, β-unsaturated carboxylic acid copolymer is, for example, 20% by mass or less with respect to 100% by mass of all repeating units contained in the α-olefin-α, β-unsaturated carboxylic acid copolymer. Preferably, vinylidene fluoride, vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, fluoroalkyl vinyl ether, allyl glycidyl ether, crotonic acid glycidyl ester, It may contain repeating units derived from monomers other than α-olefin and α, β-unsaturated carboxylic acid, such as saturated dibasic acid monoester and vinylene carbonate. Two or more repeating unit components constituting these copolymers can be used in combination. For example, when the mass of all repeating units contained in the α-olefin-α, β-unsaturated carboxylic acid copolymer is 100, [the α-olefin-derived repeating unit and α, β-unsaturated carboxylic acid-derived [Repeating unit] / [Repeating unit derived from monomer other than repeating unit derived from α-olefin and α, β-unsaturated carboxylic acid] is 80/20 to 100/0, preferably 85/15 to 99/1, more preferably 90/10 to 95/5.
The α-olefin-α, β-unsaturated carboxylic acid copolymer of the present invention has a melt flow rate (ASTM D 1238) of 5 to 150 g / 10 min, preferably 5 to 100 g / 10 min, more preferably 10 to 10 g. It is suitable to have a molecular weight corresponding to 30 g / 10 min.
ASTM D 1238 is a measure of the melt flow rate of a sample which means the amount (g) obtained when the sample is extruded for 10 minutes at 125 ° C. and a load of 21.2 N (2.16 kgf).
The α-olefin-α, β-unsaturated carboxylic acid copolymer of the present invention has an acid value of 50 to 250 KOHmg / g, preferably 100 to 200 KOHmg / g, more preferably 120 to 170 KOHmg / g. It is appropriate to be.

(1-3) Blend ratio of nitrile polymer and α-olefin-α, β-unsaturated carboxylic acid copolymer The nitrile polymer in the binder resin composition for non-aqueous electrolyte energy devices of the present invention and The blend ratio with the α-olefin-α, β-unsaturated carboxylic acid copolymer is not particularly limited. For example, the nitrile polymer / α-olefin-α, β-unsaturated carboxylic acid copolymer may be used in a mass ratio. Suitably the polymer is 5/95 to 95/5, preferably 20/80 to 90/10, more preferably 40/60 to 80/20.

(2) Preparation method of binder resin composition for non-aqueous electrolyte based energy device (2-1) Form of binder resin composition The binder resin composition of the present invention is usually a nitrile polymer and an α-olefin-α. , Β-unsaturated carboxylic acid copolymers are used individually or together in the form of a varnish dissolved or dispersed in an organic solvent containing a nitrogen-containing solvent.

  There is no restriction | limiting in particular as an organic solvent containing a nitrogen-containing solvent. Examples of the nitrogen-containing solvent include amide solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, N-dimethylethyleneurea, and N, N-dimethylpropylene. Examples include urea-based solvents such as urea and tetramethylurea. Of these, amide solvents are preferable from the viewpoint of improving the dispersion stability of the copolymer of α-olefin and α, β-unsaturated carboxylic acid, and N-methyl-2-pyrrolidone is more preferable. These nitrogen-containing solvents are used alone or in combination of two or more.

  On the other hand, as other organic solvents that can be used in combination with nitrogen-containing solvents, lactone solvents such as γ-butyrolactone and γ-caprolactone, carbonate solvents such as propylene carbonate, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, Ester solvents such as ethyl acetate, n-butyl acetate, butyl cellosolve acetate, butyl carbitol acetate, ethyl cellosolve acetate and ethyl carbitol acetate, glyme solvents such as diglyme, triglyme and tetraglyme, glycols such as ethylene glycol and propylene glycol And solvents such as hydrocarbon solvents such as toluene, xylene and cyclohexane, and sulfone solvents such as sulfolane. These organic solvents can be used alone or in combination of two or more.

  The blending ratio of the nitrogen-containing solvent in the organic solvent is, for example, preferably 20 to 100% by mass, more preferably 50 to 100% by mass, and 80 to 100% by mass with respect to the total amount of the organic solvent. % Is particularly preferred. A blending ratio of the nitrogen-containing solvent in the organic solvent of 20% by mass or more is preferable because the dispersion stability of the α-olefin-α, β-unsaturated carboxylic acid copolymer can be maintained.

  The amount of the solvent used is not particularly limited as long as the polymer constituting the binder resin composition is at least a necessary minimum amount capable of maintaining a dispersed state at room temperature, but the electrode of the later non-aqueous electrolyte energy device In the slurry preparation step in the production, since the viscosity is usually adjusted while adding a solvent, it is preferable that the amount is not excessively diluted.

(2-2) Other Additives The binder resin composition of the present invention includes, as necessary, a crosslinking component for complementing swelling resistance to other materials, for example, an electrolytic solution, flexibility and flexibility of electrodes. Various additives such as a rubber component for complementing the property, a thickener for improving the electrode coating property of the slurry, an anti-settling agent, an antifoaming agent, and a leveling agent can be blended.

(3) Use of binder resin composition of this invention The binder resin composition of this invention is utilized suitably for an energy device, especially the energy device of a nonaqueous electrolyte system.
A non-aqueous electrolyte-based energy device refers to a power storage or power generation device (apparatus) that uses an electrolyte other than water. Examples of the non-aqueous electrolyte based energy device include a lithium battery, an electric double layer capacitor, and a solar battery.

The binder resin composition of the present invention has high swelling resistance against non-aqueous electrolytes such as organic solvents other than water. Therefore, it is preferably used particularly for an electrode of a lithium battery. The binder resin composition of the present invention is not limited to non-aqueous electrolyte-based energy devices, but also paints, adhesives, curing agents, printing inks, solder resists, abrasives, electronic component sealants, and semiconductor surface protection. It can be widely used for various coating resins such as films, interlayer insulation films, varnishes for electrical insulation, and biomaterials, molding materials, and fibers.
Hereinafter, an electrode for a non-aqueous electrolyte based energy device and a lithium battery using this electrode will be described as an example.

(A) Electrode for Nonaqueous Electrolyte Energy Device The nonaqueous electrolyte energy device electrode of the present invention has a current collector and a mixture layer provided on at least one surface of the current collector. is there.
The binder resin composition of this invention can be used as a material which comprises this mixture layer.

(A-1) Current Collector The current collector in the present invention may be a substance having conductivity, and for example, a metal can be used. Specific examples of metals that can be used include aluminum, copper, and nickel.
Furthermore, the shape of the current collector is not particularly limited, but a thin film is preferable from the viewpoint of increasing the energy density of a lithium battery that is a non-aqueous electrolyte energy device. The thickness of a collector is 5-30 micrometers, for example, Preferably, it is 8-25 micrometers.

(A-2) Mixture layer The mixture layer in this invention consists of the said binder resin composition containing an active material, arbitrary electroconductive fillers, etc.
For example, the mixture layer is prepared by dissolving the binder resin composition of the present invention, the solvent, the active material, and any conductive filler in a solvent to prepare a slurry, and applying the slurry to the current collector. Can be obtained by dry removal.

(A-2-1) Active material The active material used in the present invention is, for example, any material that can reversibly insert and release lithium ions by charging and discharging a lithium battery that is a non-aqueous electrolyte energy device. There is no particular limitation.
However, the positive electrode has a function of releasing lithium ions at the time of charging and receiving lithium ions at the time of discharging, while the negative electrode has a function opposite to that of the positive electrode of receiving lithium ions at the time of charging and releasing lithium ions at the time of discharging. Therefore, different active materials are usually used for the active material used in the positive electrode and the negative electrode in accordance with the respective functions.

As the negative electrode active material, for example, carbon materials such as graphite, amorphous carbon, carbon fiber, coke, activated carbon and the like are preferable, and a composite of such a carbon material and a metal such as silicon, tin, silver, or an oxide thereof. Things can also be used.
On the other hand, as the positive electrode active material, for example, a lithium-containing metal composite oxide containing at least one metal selected from lithium and iron, cobalt, nickel, and manganese is preferable. Examples of the lithium-containing metal composite oxide include lithium cobaltate, lithium manganate, and lithium nickelate. These active materials are used alone or in combination of two or more.

(A-2-2) Electrically conductive filler An electrically conductive filler is arbitrarily used in order to improve the electronic conductivity in the mixture layer of an electrode. The conductive filler used in the present invention is not particularly limited, and examples thereof include graphite, carbon black, acetylene black, and the like. Usually, the conductive filler is used as a conductive aid on the positive electrode side. These conductive fillers may be used alone or in combination of two or more.

(A-2-3) Solvent The solvent used for forming the mixture layer is not particularly limited as long as it can dissolve or disperse the binder resin composition uniformly. As such a solvent, the solvent used when preparing a varnish by melt | dissolving or disperse | distributing a binder resin composition is used as it is. Of these, amides, ureas or lactones or mixed solvents containing them are preferred, and among these, N-methyl-2-pyrrolidone or mixed solvents containing it are more preferred.
These solvents may be used alone or in combination of two or more.

(A-3) Electrode production method The method for producing an electrode for a non-aqueous electrolyte-based energy device of the present invention is not particularly limited and can be produced using a known electrode production method. For example, a slurry containing the binder resin composition, solvent, active material, and optional conductive filler is applied to at least one surface of the current collector, then the solvent is dried and removed, and the current is collected by rolling as necessary. It can be produced by forming a mixture layer on the body surface.

Here, application | coating can be performed using a micro applicator, a comma coater, etc., for example. It is appropriate that the application is performed so that the negative electrode / positive electrode theoretical capacity ratio per unit area is 1 or more, preferably 1 to 1.1, and more preferably 1 to 1.05, in the facing electrode. . Here, `` the negative electrode / positive electrode theoretical capacity ratio per unit area '' is the following formula:
[(The negative electrode theoretical capacity mA / g) × (the negative electrode application amount g / cm ² )] ÷ [(the positive electrode theoretical capacity mA / g) × (the positive electrode application amount g / cm ² )]
Can be obtained from When the negative electrode / positive electrode theoretical capacity ratio per unit area is 1 or more, Li ions that are taken into the negative electrode during the first charge and are not released by discharge can be supplemented.
The amount of slurry applied is, for example, such that the dry weight of the mixture layer is, for example, ^{2 to} 30 mg / cm ² , preferably 8 to 15 mg / cm ² .
The removal of the solvent is performed, for example, by drying at 50 to 150 ° C., preferably 80 to 120 ° C., for 1 to 20 minutes, more preferably 3 to 10 minutes.

Rolling is performed using, for example, a roll press machine, and the bulk density of the mixture layer is, for example, 1 to 2 g / cm ³ , preferably 1.2 to 1.8 g / cm when the mixture layer of the negative electrode is used. ^In the case of the positive electrode material mixture layer, it is pressed so as to be, for example, 2 to 5 g / cm ³ , preferably ³ to 4 g / cm ³ . Further, in order to remove residual solvent and adsorbed water in the electrode, for example, vacuum drying may be performed at 100 to 150 ° C. for 1 to 20 hours.

(B) Lithium battery The electrode for non-aqueous electrolyte energy devices of the present invention can be further combined with an electrolyte to produce a lithium battery that is a non-aqueous electrolyte energy device.

(B-1) Electrolytic Solution The electrolytic solution used in the present invention is not particularly limited as long as it functions as a lithium battery that is a nonaqueous electrolytic solution energy device, for example. As the electrolytic solution, an electrolytic solution other than water, for example, carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate, lactones such as γ-butyrolactone, trimethoxymethane, 1, Ethers such as 2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran and 2-methyltetrahydrofuran, sulfoxides such as dimethylsulfoxide, oxolanes such as 1,3-dioxolane and 4-methyl-1,3-dioxolane , Nitrogen-containing compounds such as acetonitrile, nitromethane, N-methyl-2-pyrrolidone, esters such as methyl formate, methyl acetate, butyl acetate, methyl propionate, ethyl propionate, phosphate triester , Glymes such as diglyme, triglyme and tetraglyme, ketones such as acetone, diethyl ketone, methyl ethyl ketone and methyl isobutyl ketone, sulfones such as sulfolane, oxazolidinones such as 3-methyl-2-oxazolidinone, 1,3-propane sultone, 4-butane sultone, in an organic solvent such as sultones such _{Nafutasuruton, LiClO 4, LiBF, LiI,} LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, LiCl, LiBr, A solution in which an electrolyte such as LiB (C ₂ H ₅ ) ₄ , LiCH ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li [(CO ₂ ) ₂ ] ₂ B is dissolved is used. Can be mentioned.

Among these, solution is preferred in which LiPF ₆ was dissolved in carbonates. The electrolytic solution is prepared by using, for example, the organic solvent and the electrolyte alone or in combination of two or more.

(B-2) Manufacturing Method of Lithium Battery Although there is no particular limitation on the manufacturing method of the lithium battery that is the non-aqueous electrolyte energy device of the present invention, any known method can be used. For example, two electrodes, a positive electrode and a negative electrode, are superposed on a stainless steel coin outer packaging container via a separator made of polyethylene microporous film, covered with a stainless steel cap via a polypropylene packing, and used for coin cell production. Seal with a caulking device to obtain a coin-type battery. At this time, each electrode is arrange | positioned so that the mixture layer side may contact | connect electrolyte solution.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited by these.
<Preparation of binder resin composition>
Synthesis example 1
[Nitrile polymer 1]
1804 g of purified water is charged into a 3 liter separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen gas introduction pipe, and the temperature is raised to 74 ° C. while stirring under a nitrogen gas flow rate of 200 ml / min. After that, the ventilation of nitrogen gas was stopped.

  Next, an aqueous solution obtained by dissolving 0.968 g of a polymerization initiator ammonium persulfate in 76 g of purified water was added, and immediately, 188.0 g of nitrile group-containing monomer acrylonitrile and 12.0 g of acrylic acid of carboxyl group-containing monomer ( The mixture was added dropwise over 2 hours while maintaining the system temperature at 74 ± 2 ° C. After proceeding the reaction at the same temperature for 1 hour, an aqueous solution obtained by dissolving 1.935 g of ammonium persulfate in 13 g of purified water was further added to the suspended reaction system, and the reaction was further proceeded at the same temperature for 1 hour.

  Next, the temperature was raised to 90 ° C., and the reaction was allowed to proceed for 1 hour while maintaining the temperature of the system at 90 ± 2 ° C. Then, an aqueous solution in which 0.968 g of ammonium persulfate was dissolved in 8 g of purified water was further added. The reaction was further continued for 1 hour. Then, after cooling to 40 degreeC over 1 hour, stirring was stopped and it stood to cool at room temperature overnight, and the reaction liquid in which the nitrile polymer in this invention precipitated was obtained.

  The reaction solution was filtered by suction, and the collected wet precipitate was washed 3 times with 1800 g of purified water, dried in vacuo at 80 ° C. for 10 hours, isolated and purified, and repeatedly derived from a nitrile group-containing monomer. A purified powder of a nitrile polymer 1 containing 80% by mass or more of units (repeating unit derived from a nitrile group-containing monomer: 94% by mass) was obtained.

Synthesis example 2
[Nitrile polymer 2]
183.8 g of acrylonitrile as a nitrile group-containing monomer, 9.7 g of acrylic acid as a carboxyl group-containing monomer (ratio of 0.039 mol with respect to 1 mol of acrylonitrile) and the above general formula (I) Except that 6.5 g of methoxytriethylene glycol acrylate (trade name: NK ester AM-30G, manufactured by Shin-Nakamura Chemical Co., Ltd.) is used (a ratio of 0.0085 mol to 1 mol of acrylonitrile). Is a purified powder of nitrile polymer 2 (repeat unit derived from nitrile group-containing monomer: 92% by weight) containing 80% by weight or more repeat unit derived from nitrile group-containing monomer in the same manner as in Synthesis Example 1. Got.

Synthesis example 3
[Nitrile polymer 3]
150.0 g of nitrile group-containing monomer acrylonitrile, 25.0 g of carboxyl group-containing monomer acrylic acid (a ratio of 0.123 mol to 1 mol of acrylonitrile) and the above general formula (I) In the same manner as in Synthesis Example 1, except that 25.0 g of the monomer methoxytriethylene glycol acrylate (a ratio of 0.041 mol with respect to 1 mol of acrylonitrile) is used, the nitrile group-containing monomer-derived repeat A purified powder of nitrile polymer 3 having a unit content of less than 80% by mass (repeating unit derived from a nitrile group-containing monomer: 75% by mass) was obtained.

Example 1
70 g of purified powder of nitrile polymer 1 obtained in Synthesis Example 1 in a 3 liter separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen gas introduction pipe, α-olefin-α, β-unsaturated As a carboxylic acid copolymer, ethylene-acrylic acid copolymer (manufactured by Dow Chemical Co., Ltd., trade name: PRIMACOR 5980I, melt flow rate (ASTM D 1238): 15 g / 10 min, acid value: 156 KOH mg / g) pellets 30 g, N -1567 g of methyl-2-pyrrolidone (hereinafter referred to as NMP) was charged, and the temperature was raised to 140 ° C. with stirring under a trace amount (5 ml / min or less) of nitrogen gas (in a nitrogen atmosphere).

  After maintaining at the same temperature for 2 hours, the nitrile polymer and the ethylene-acrylic acid copolymer are dissolved in NMP, and then cooled to room temperature, nitrile polymer / α-olefin-α, β-unsaturated carboxylic acid. An acid copolymer = 70/30 (mass ratio) varnish (resin content 6 mass%) was prepared. When cooled to room temperature, the resin precipitated as fine particles and was in a dispersed state.

Example 2
80 g of purified powder of nitrile polymer 2 obtained in Synthesis Example 2 in a 3 liter separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen gas introduction pipe, α-olefin-α, β-unsaturated As the carboxylic acid copolymer, ethylene-acrylic acid copolymer (manufactured by Dow Chemical Co., Ltd., trade name: PRIMACOR 5980I, melt flow rate (ASTM D 1238): 15 g / 10 min, acid value: 156 KOH mg / g) pellets 20 g, NMP 1567 g The mixture was heated to 140 ° C. with stirring under a very small amount (5 ml / min or less) of nitrogen gas (under nitrogen atmosphere).

  After maintaining at the same temperature for 2 hours, the nitrile polymer and the ethylene-acrylic acid copolymer are dissolved in NMP, and then cooled to room temperature, nitrile polymer / α-olefin-α, β-unsaturated carboxylic acid. An acid copolymer = 80/20 (mass ratio) varnish (resin content 6 mass%) was prepared. When cooled to room temperature, the resin precipitated as fine particles and was in a dispersed state.

Comparative Example 1
A 3 liter separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen gas introduction pipe was charged with 100 g of the purified powder of nitrile polymer 2 obtained in Synthesis Example 2 and 1567 g of NMP, and a very small amount (5 ml / min) The temperature was raised to 70 ° C. with stirring under nitrogen gas ventilation (under nitrogen atmosphere).

  The mixture was kept at the same temperature for 6 hours to dissolve the nitrile polymer in NMP and then cooled to room temperature to prepare a varnish of nitrile polymer 2 (resin content: 6% by mass). Even when cooled to room temperature, the resin did not precipitate and remained in solution.

Comparative Example 2
80 g of purified powder of nitrile polymer 3 obtained in Synthesis Example 3 in a 3 liter separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen gas introduction pipe, α-olefin-α, β-unsaturated As the carboxylic acid copolymer, ethylene-acrylic acid copolymer (manufactured by Dow Chemical Co., Ltd., trade name: PRIMACOR 5980I, melt flow rate (ASTM D 1238): 15 g / 10 min, acid value: 156 KOH mg / g) pellets 20 g, NMP 1567 g The mixture was heated to 140 ° C. with stirring under a very small amount (5 ml / min or less) of nitrogen gas (under nitrogen atmosphere).
After maintaining at the same temperature for 2 hours, the nitrile polymer and the ethylene-acrylic acid copolymer are dissolved in NMP, and then cooled to room temperature, nitrile polymer / α-olefin-α, β-unsaturated carboxylic acid. An acid copolymer = 80/20 (mass ratio) varnish (resin content 6 mass%) was prepared. When cooled to room temperature, the resin precipitated as fine particles and was in a dispersed state.

Comparative Example 3
Ethylene-acrylic acid copolymer (Dow Chemical Co., Ltd.) as an α-olefin-α, β-unsaturated carboxylic acid copolymer in a 3 liter separable flask equipped with a stirrer, thermometer, cooling pipe and nitrogen gas introduction pipe Product name: PRIMACOR 5980I, melt flow rate: 15 g / 10 min, acid value: 156 KOH mg / g) 70 g of pellets and NMP 1680 g are charged, and trace amount (5 ml / min or less) of nitrogen gas is passed (under nitrogen atmosphere) The temperature was raised to 140 ° C. with stirring.

  Holding at the same temperature for 2 hours, the ethylene-acrylic acid copolymer was dissolved in NMP, then cooled to room temperature, and a varnish of a copolymer of α, β-unsaturated carboxylic acid (resin content 4 mass%) Was prepared. When cooled to room temperature, the resin precipitated as fine particles and was in a dispersed state.

Comparative Example 4
A polyvinylidene fluoride (PVDF) varnish (manufactured by Kureha Chemical Industry Co., Ltd., trade name: KF9130, NMP solution, resin content 13 mass%), which is widely used as an NMP solvent-based binder, was prepared.
The compositions of the polymers obtained in Examples 1-2 and Comparative Examples 1-4 are as follows.

<Evaluation of binder resin composition>
(1) Swelling resistance with respect to electrolyte solution Each varnish of Examples 1-2 and Comparative Examples 1-4 was cast on a polyethylene terephthalate (hereinafter referred to as PET) sheet and dried on a hot plate at 100 ° C for 5 hours. Thereafter, the dried residue was peeled off from the PET sheet and subjected to vacuum heat treatment with a vacuum dryer at 120 ° C. for 5 hours to obtain a resin film.

Next, the obtained film was cut into four 1.5 cm square pieces, transferred into a glove box under an atmosphere filled with argon gas, and the dry mass was measured. Then, an electrolyte (made by Kishida Chemical Co., Ltd., LiPF at a concentration of 1M) was used. ₆ was dissolved in an equal volume mixed solution of ethylene carbonate, dimethyl carbonate and diethyl carbonate (the same applies hereinafter) under two conditions (23 ° C. for 24 hours, 50 ° C. for 24 hours).

  Thereafter, the film was pulled up from the electrolytic solution, the electrolytic solution adhering to the surface was wiped off with dry towel paper, and the mass was immediately measured. The swelling resistance to the electrolytic solution was evaluated by the degree of swelling calculated from the following formula. In the following formula, it can be judged that the smaller the degree of swelling, the better the swelling resistance against the electrolytic solution.

Swelling degree (mass%) = [(mass after soaking−dry weight before soaking) / dry weight before soaking] × 100

(2) Adhesiveness with negative electrode current collector, flexibility / flexibility of electrode Each varnish of Examples 1-2 and Comparative Examples 1-4, and negative electrode active material (trade name, manufactured by Hitachi Chemical Co., Ltd.) : MAG, massive artificial graphite, average particle size 20 μm) were blended so that the solid content (resin component) in the varnish was 3 parts by mass and the negative electrode active material was 97 parts by mass, and then NMP was 45 in total solids. A slurry was prepared by adding and kneading to a mass%.

Then, the obtained slurry was mixed with the negative electrode so that the dry weight of the mixture layer was 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11 mg / cm ² , respectively. It apply | coated uniformly with the microapplicator on the one side surface of the electric conductor (Hitachi Cable Co., Ltd. product, rolled copper foil, thickness 10 micrometers, dimension 200x100 mm).

Subsequently, the coated material was dried with a hot air dryer at 90 ° C. for 1 hour to form a mixture layer, and then cut into strips with dimensions of 10 cm long × 2 cm wide. Adhesiveness with the negative electrode current collector was determined by aligning both ends of the strip-shaped test piece (mixture layer dry mass 7 mg / cm ² ) with the mixture layer-forming surface facing outward, and from the center of the test piece. When the portions separated by 1 cm toward the both ends were sandwiched so that the surface of the current collector was in contact, the case where the mixture layer was not peeled off from the negative electrode current collector was evaluated as good, and the case where it was peeled off was evaluated as bad.

On the other hand, the flexibility / flexibility of the electrode is determined by the strip-shaped test piece (the dry weight of the mixture layer is 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, respectively). 11 mg / cm ² ), in order from the test piece with the dry mass of the mixture layer having a small dry mass, both ends of the test piece are aligned with the mixture layer forming surface on the outside, and 1 cm each from the center of the test piece toward both ends. When the separated portion was sandwiched so that the surface of the current collector was in contact, the mixture layer was evaluated by the dry weight of the mixture layer of the test piece when an appearance defect such as a crack occurred in the mixture layer. It can be judged that the larger the mixture layer dry mass of the test piece, the better the flexibility and flexibility of the electrode.

<Battery evaluation>
(1) Production of Coin Battery for Negative Electrode Evaluation Slurry prepared using the binder resin composition varnish obtained in Examples 1-2 and Comparative Examples 1-4 above ("(2) Anode current collector and Adhesiveness, electrode flexibility / flexibility ”), and negative electrode current collector (Hitachi Cable Ltd., rolled copper foil) so that the dry weight of the mixture layer is 12.5 mg / cm ² , respectively. , A thickness of 14 μm, 200 × 100 mm) was uniformly applied with a microapplicator.

Next, the coated material is dried with a hot air dryer at 90 ° C. for 1 hour to form a mixture layer, and then compression molded so that the bulk density of the mixture layer is 1.5 g / cm ³ with a roll press. And cut into a circle having a diameter of 0.9 cm.
Then, this was vacuum-heat-treated for 5 hours with a 120 degreeC vacuum dryer, and the working electrode was prepared.

Separately, 1 mm thick metal lithium (manufactured by Mitsui Kinzoku Co., Ltd.) whose surface was lightly polished was cut into a circle having a diameter of 1.5 cm and prepared as a counter electrode.
Further, as an insulator for separating the working electrode and the counter electrode, a separator (manufactured by Tonen Tapirs Co., Ltd., polyethylene microporous membrane, thickness 25 μm, the same applies hereinafter) was cut into a circle having a diameter of 1.8 cm and prepared.

In a glove box under an atmosphere filled with argon gas, the working electrode and the counter electrode were laminated in the order of working electrode-separator-counter electrode on a stainless steel coin outer container having a diameter of 2.0 cm. At this time, several drops of the electrolytic solution were dropped before and after the separators were stacked.
Furthermore, using a copper foil cut into a circle having a diameter of 1.5 cm as a spacer, the spacer portions are stacked so that the total of the spacer portions is 240 μm, and a stainless steel cap is put on via a polypropylene packing, for coin cell production. Sealed with a caulking device to produce a negative electrode evaluation battery. At this time, the working electrode was disposed so that the mixture layer side was in contact with the electrolytic solution.

(2) Initial charge / discharge characteristics of coin battery Using the charge / discharge device (TOSCAT3100, manufactured by Toyo System Co., Ltd.), the charge current of 0.2 mA (0.08C) in a constant temperature bath at 25 ° C. ) And constant current charging to 0V. The constant current charging is precisely a discharge because the counter electrode is a lithium metal and the working electrode is a positive electrode due to the potential. However, here, the lithium ion insertion reaction into the working electrode graphite is defined as “charging”.

  When the voltage reaches 0 V, switching to constant voltage charging is continued until the current value decays to 0.02 mA, and then the discharge end voltage reaches 1.5 V at a discharge current of 0.2 mA (0.08 C). Until constant current discharge. At this time, the charge capacity and discharge capacity per gram of graphite were measured, and the irreversible capacity and charge / discharge efficiency were calculated, and the initial charge / discharge characteristics of the coin battery for negative electrode evaluation were evaluated.

The irreversible capacity at the time of the first charge / discharge is obtained from [initial charge capacity−initial discharge capacity], and the smaller the irreversible capacity, the better.
In addition, the charge / discharge efficiency (%) at the first charge / discharge is
[Charge / discharge efficiency (%) = (initial discharge capacity / initial charge capacity) × 100]
The charge / discharge efficiency at the time of the first charge / discharge is better as it is obtained.
The discharge capacity is 345 mAh / g or more, preferably 350 mAh / g or more, the irreversible capacity is 35 mAh / g or less, preferably 30 mAh / g or less, and the charge / discharge efficiency is 90% or more, preferably If it is 92% or more, the first-time charge / discharge characteristic of a single electrode cell will be evaluated as favorable.

(3) Evaluation of discharge rate characteristic of coin battery Under the same conditions as the initial charge / discharge characteristic, after one cycle of charge / discharge, the same as the initial charge / discharge except that the final voltage at constant current discharge is changed to 1V. Three more cycles were performed under the same conditions (discharge 0.08C).

Thereafter, one cycle was performed under the same conditions as the previous three cycles except that the discharge current during constant current discharge was increased to 0.7 mA (0.27 C). Next, the discharge current was increased to 1.3 mA (0.5 C), 2.6 mA (1.0 C), 3.9 mA (1.5 C), and 5.2 mA (2.0 C), and each cycle was charged. The discharge was repeated. The ratio of the discharge capacity at 2.0C in the eighth cycle to the discharge capacity at 0.08C in the fourth cycle was expressed as a percentage, and the discharge rate characteristics were evaluated. A larger value indicates better discharge rate characteristics.
The results of Examples and Comparative Examples are shown in Tables 1 and 2.

  As shown in Tables 1 and 2, the binder resin compositions (Examples 1 and 2) of the present invention are superior in flexibility and flexibility of the electrode as compared with Comparative Example 1 and are more electrolytic than Comparative Example 2. Compared with Comparative Examples 2 and 3, the initial charge / discharge characteristics of the coin battery are good (the discharge capacity and charge / discharge efficiency are large and the irreversible capacity is small), and the rate characteristics are also excellent. It is clear that the adhesiveness is excellent. From the above, it can be said that the binder resin compositions (Examples 1 and 2) of the present invention are excellent in the property balance as compared with Comparative Examples 1 to 4.

Claims (12)

  A nitrile polymer containing 80% by mass or more of a repeating unit derived from a nitrile group-containing monomer and an α-olefin-α containing a repeating unit derived from an α-olefin and a repeating unit derived from an α, β-unsaturated carboxylic acid. A binder resin composition for non-aqueous electrolyte-based energy device electrodes, comprising a β-unsaturated carboxylic acid copolymer.   The binder resin composition for non-aqueous electrolyte-type energy device electrodes according to claim 1, wherein the nitrile group-containing monomer is acrylonitrile. The nitrile polymer is a repeating unit derived from a nitrile group-containing monomer, a repeating unit derived from a carboxyl group-containing monomer, and / or the following general formula (I)

(Wherein R ₁ is H or CH ₃ , R ₂ is H or a monovalent hydrocarbon group, and n is an integer of 1 to 50)
The binder resin composition for non-aqueous electrolyte system energy device electrodes of Claim 1 or 2 characterized by including the repeating unit derived from the monomer represented by these.   The binder resin composition for non-aqueous electrolyte-type energy device electrodes according to claim 3, wherein the carboxyl group-containing monomer is acrylic acid.   The binder resin composition for nonaqueous electrolyte type energy device electrodes according to claim 3, wherein the monomer represented by the general formula (I) is methoxytriethylene glycol acrylate.   The repeating unit derived from the carboxyl group-containing monomer is represented by 0.01 to 0.2 mol and / or the general formula (I) with respect to 1 mol of the repeating unit derived from the nitrile group-containing monomer. The repeating unit derived from a monomer is 0.001 to 0.2 mol, The binder resin composition for non-aqueous electrolyte system energy device electrodes according to any one of claims 3 to 5.   The binder resin composition for a non-aqueous electrolyte-based energy device electrode according to any one of claims 1 to 6, wherein the α-olefin is ethylene and the α, β-unsaturated carboxylic acid is acrylic acid.   The α-olefin-α, β-unsaturated carboxylic acid copolymer has a molecular weight corresponding to a melt flow rate (ASTM D 1238) of 5 to 150 g / 10 min and an acid value of 50 to 250 KOHmg / g. The binder resin composition for non-aqueous electrolyte system energy device electrodes according to claim 7.   An organic solvent containing a nitrogen-containing solvent, the nitrile copolymer dissolved in the organic solvent, and the α-olefin-α, β-unsaturated carboxylic acid copolymer dispersed in the organic solvent. The binder resin composition for non-aqueous electrolyte system energy device electrodes in any one of Claims 1-8 containing.   The nonaqueous electrolytic solution according to claim 1, comprising a current collector and a mixture layer provided on at least one surface of the current collector, wherein the mixture layer contains an active material. A non-aqueous electrolyte type energy device electrode comprising a binder resin composition for a system energy device electrode.   A nonaqueous electrolytic solution energy device comprising the nonaqueous electrolytic solution energy device electrode according to claim 10.   The nonaqueous electrolytic solution energy device according to claim 11, wherein the nonaqueous electrolytic solution energy device is a lithium battery.