KR20180099560A - Binder aqueous solution for lithium ion battery, slurry for lithium ion battery and method for producing same, electrode for lithium ion battery, separator for lithium ion battery, separator/electrode layered product for lithium ion battery and lithium ion battery - Google Patents

Abstract

Provided are an aqueous binder solution for lithium ion batteries, slurry for lithium ion batteries and a production method thereof, an electrode for lithium ion batteries, a separator for lithium ion batteries, a separator/electrode laminate for lithium ion batteries, and a lithium ion battery. To this end, the aqueous binder solution for lithium ion batteries comprises poly(meth)acrylamide (A) containing a water-soluble trihydroxy silyl group which is a polymer of a monomer group consisting of at least 60 mol% of a compound (a) containing a (meth)acrylaminde group and 0.05-0.80 mol% of a trihydroxy silyl compound (b) having a double bond having a vinyl group or methacryloxy group, with respect to 100 mol% of a monomer group.

Description

TECHNICAL FIELD The present invention relates to a binder aqueous solution for a lithium ion battery, a slurry for a lithium ion battery and a method for producing the same, an electrode for a lithium ion battery, a separator for a lithium ion battery, a separator / electrode laminate for a lithium ion battery, ION BATTERY AND METHOD FOR PRODUCING SAME, ELECTRODE FOR LITHIUM ION BATTERY, SEPARATOR FOR LITHIUM ION BATTERY, SEPARATOR / ELECTRODE LAYERED PRODUCT FOR LITHIUM ION BATTERY AND LITHIUM ION BATTERY}

The present disclosure relates to a binder aqueous solution for a lithium ion battery, a slurry for a lithium ion battery and a production method thereof, an electrode for a lithium ion battery, a separator for a lithium ion battery, a separator / electrode laminate for a lithium ion battery, and a lithium ion battery.

Lithium ion batteries are small and light in weight, have high energy density, and are capable of repeated charge / discharge, and are used for a wide variety of applications. Therefore, in recent years, improvement of battery members such as electrodes and separators has been studied for the purpose of further enhancing the performance of lithium ion batteries.

A positive electrode and a negative electrode of a lithium ion battery are each formed by dispersing an electrode active material and a binder resin in a solvent to form a slurry into a collector (for example, a metal foil) ), Drying and removing the solvent to form an electrode layer (electrode layer), and then pressing and molding the resultant with a roll press machine or the like.

In recent years, various electrode active materials have been proposed as electrode active materials in terms of increasing the battery capacity (battery capacity) in electrodes for lithium ion batteries. However, depending on the electrode active material, it tends to swell and contract due to charging and discharging. As a result, there has been a problem that the electrode for the lithium ion battery is liable to change in volume (spring back property) from the beginning of repetition of charging and discharging, and the electrical characteristics such as the cycle characteristics of the lithium ion battery using the electrode tends to decrease .

Thus, studies have been made to solve the above problems by means of a binder resin in four fields. For example, polyimide (Patent Document 1) and polyacrylic acid (Patent Document 2) are known. Patent Document 3 discloses a negative electrode slurry comprising polyacrylamide and an active material having a predetermined average particle diameter. Patent Document 4 proposes a particulate binder containing an alkoxysilyl group-containing monomer. Patent Document 5 proposes a slurry composition comprising a water-soluble polymer containing a silicon-containing monomer, a particulate binder, and a negative electrode active material.

A heat-resistant separator in which a coating layer (heat-resistant layer (heat-resistant layer)) containing ceramic fine particles and a binder is formed on the surface of a polyolefin microporous membrane has recently been proposed for a separator of a lithium ion battery. It is known that the coating layer has an effect of suppressing shrinkage of the separator even when exposed to a high temperature. However, the obtained heat-resistant separator has a problem that the adhesion between the coating layer and the polyolefin microporous film can not be maintained due to deformation such as warpage during transportation in the production line or in the battery cell, and thus the separator is liable to drop.

Thus, in the four seasons, studies have been made to solve the above problems by means of a binder resin. For example, in Patent Document 6, there is proposed a method in which a functional group capable of crosslinking with the surface of inorganic oxide particles It is said that the use of nitrogen-containing aromatic polymer improves the interaction and exhibits high heat resistance. Patent Document 7 discloses a porous film comprising a water-soluble polymer, an inorganic filler and a water-insoluble particulate polymer, wherein the water-insoluble particulate polymer has a cross-linkable group of an epoxy group and / or a hydroxyl group The present invention proposes to prevent short-circuiting during battery operation by forming the porous protective film.

Japanese Unexamined Patent Application Publication No. 2013-089437 Japanese Patent Application Laid-Open No. 2005-216502 Japanese Unexamined Patent Application Publication No. 2015-106488 Japanese Unexamined Patent Application Publication No. 2016-100149 Japanese Patent No. 6048070 Japanese Unexamined Patent Application Publication No. 2011-187274 Japanese Patent No. 5,704,223

With regard to the electrode of the lithium ion battery, the polyimide of Patent Document 1 is obtained by dissolving a polyamic acid as a precursor in a solvent containing an organic solvent such as N-methyl-2-pyrrolidone (NMP) The use of an organic solvent such as NMP is extremely large in environmental load at the time of application and drying as compared with the case where an aqueous solvent is used in mass production due to an increase in demand in the future.

The polyacrylic acid described in Patent Document 2 has a problem that the initial discharge capacity (initial discharge capacity) is lowered because lithium ions absorbed in the active material are charged into the carboxyl group at the time of charging. Furthermore, no description is given about spring back resistance.

Patent Document 3 proposes an electrode slurry containing polyacrylamide and an active material having a predetermined average particle diameter, but does not describe the springback resistance of the electrode.

Patent Document 4 proposes a particulate binder containing an alkoxysilyl group-containing monomer, but it is known that particulate binders contribute to electrode adhesion but have poor springback resistance.

Patent Document 5 proposes a slurry composition comprising a water-soluble polymer containing a silicon-containing monomer, a particulate binder, and an electrode active material, but the slurry dispersion safety is low. Further, the springback resistance for maintaining the conductive path between the active materials is not described.

With respect to the separator of the lithium ion battery, conventionally, as the solvent of the slurry for producing the porous film and the adhesive layer, an organic solvent is generally used. However, in the production method using the organic solvent described in Patent Document 6, there is a problem that the cost is required for recycling of the organic solvent, or the safety is secured by using an organic solvent.

Further, when the particulate polymer having the heat-resistant crosslinking agent described in Patent Document 7 is used as a binder, the dispersibility of the fine particles in the slurry is not sufficient, and the fine particles aggregate and precipitate with time, And thus it is difficult to produce a uniform porous film.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrode capable of imparting excellent spring resistance and electrical properties to a lithium ion battery, and an electrode having excellent heat shrinkability, endurance resistance, To a lithium ion battery, which is capable of producing a separator. In the present disclosure, the endocrine disruption means binding property between the ceramic fine particles, and the substrate adhesion property means the adhesion between the substrate and the layer (coating layer) obtained by applying the slurry according to the present invention to the substrate and drying .

The present inventors have intensively studied to solve the above problems and found that a water-soluble tri (meth) acrylamide compound obtained by polymerizing a (meth) acrylamide group-containing compound (a) and a trihydrosiloxyl compound (Meth) acrylamide (A) containing a hydroxy-silyl group, the present inventors have found out what can solve the above problems and accomplished the present invention.

The following items are provided by the present disclosure.

(Item 1)

With respect to 100 mol% of the monomer group,

(Meth) acrylamide group-containing compound (a) in an amount of 60 mol% or more,

Is a polymer of a monomer group containing 0.05 to 0.80 mol% of a tri-hydroxysilyl compound (b) having a vinyl group or a double bond containing a (meth) acryloxy group

The water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A)

A binder aqueous solution for a lithium ion battery.

(Item 2)

With respect to 100 mol% of the monomer group,

(Meth) acrylamide group-containing compound (a) in an amount of 60 mol% or more,

Is a polymer of a monomer group containing 0.05 to 0.80 mol% of a tri-hydroxysilyl compound (b) having a vinyl group or a double bond containing a (meth) acryloxy group

The water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A)

≪ / RTI >

(Item 3)

A slurry for a lithium ion battery as described in the item above, comprising a trihydroxy silyl compound or a tetrahydroxy silyl compound.

(Item 4)

The slurry for a lithium ion battery according to any one of the above items, wherein the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) has a gel fraction of 50% or more.

(Item 5)

A slurry for a lithium ion battery according to any one of the above items, including the electrode active material (B).

(Item 6)

The slurry for a lithium ion battery according to any one of the items above, wherein the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) is contained in an amount of 1 to 15 mass% based on 100 mass% of the electrode active material (B).

(Item 7)

The slurry for a lithium ion battery according to any one of the above items, wherein the electrode active material (B) comprises 20% by mass or more of silicon or silicon oxide covered with a carbon layer.

(Item 8)

A slurry for a lithium ion battery according to any one of the above items, including the ceramic fine particles (C).

(Item 9)

The slurry for a lithium ion battery according to any one of the above items, wherein the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) is contained in an amount of 1 to 15 mass% based on 100 mass% of the ceramic fine particles (C).

(Item 10)

With respect to 100 mol% of the monomer group,

(Meth) acrylamide group-containing compound (a) in an amount of 60 mol% or more,

Is a polymer of a monomer group containing 0.05 to 0.80 mol% of a tri-hydroxysilyl compound (b) having a vinyl group or a double bond containing a (meth) acryloxy group

A process for producing a slurry for a lithium ion battery according to any one of the above items, which comprises a step of mixing water with a poly (meth) acrylamide (A) containing a water-soluble trihydroxy silyl group.

(Item 11)

An electrode for a lithium ion battery obtained by applying a slurry for a lithium ion battery according to any one of the items above to a current collector and drying the slurry.

(Item 12)

The electrode for a lithium ion battery according to any one of the above items, wherein the current collector is a copper foil.

(Item 13)

A lithium ion battery comprising an electrode for a lithium ion battery according to any one of the above items.

(Item 14)

A separator for a lithium ion battery, which is obtained by applying a slurry for a lithium ion battery according to any one of the above items to a porous polyolefin resin base material or a plastic nonwoven fabric and drying the slurry.

(Item 15)

A separator / electrode laminate for a lithium ion battery, which is obtained by applying a slurry for a lithium ion battery according to any one of the items above to electrodes.

(Item 16)

A lithium ion battery comprising the separator for a lithium ion battery according to any one of the above items and / or the separator / electrode laminate for a lithium ion battery according to item 15.

In the present disclosure, one or more of the above-described features may be provided in combination in addition to the specified combination.

By using the aqueous binder solution for a lithium ion battery of the present invention and the slurry for a lithium ion battery, it is possible to provide a lithium ion battery having improved battery capacity and spring resistance.

By using the aqueous binder solution for a lithium ion battery and the slurry for a lithium ion battery of the present invention, it is possible to provide a lithium ion battery separator having improved heat shrinkability, resistance to breakage, adhesion to a substrate, rate characteristics, and output characteristics.

Throughout this disclosure, ranges of numerical values such as physical properties, contents and the like can be set appropriately (for example, by selecting from values of upper and lower limits described in the following items). More specifically, when the upper limit of the value a is exemplified as A1, A2, A3, and the lower limit of the value a is exemplified as B1, B2, B3, A3 or less, B1 or more, B2 or more, B3 or more, A1 to B1, A1 to B2, A1 to B3, A2 to B1, A2 to B2, A2 to B3, A3 to B1, A3 to B2, .

[1. Binder aqueous solution for lithium ion battery: also referred to as aqueous solution]

The present disclosure relates to a resin composition comprising 60 mol% or more of a (meth) acrylamide group-containing compound (a) relative to 100 mol% of a monomer group and a double bond-containing tri (meth) (A) comprising a water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) which is a polymer of a monomer group containing 0.05 to 0.80 mol% of a hydroxy-silyl compound (b) .

<Water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A): also referred to as component (A)>

The water-soluble trihydroxysilyl group-containing poly (meth) acrylamide is preferably a water-soluble trihydric hydroxy group-containing poly (meth) acrylamide among polymers of a monomer group containing a (meth) acrylamide group- it means.

In the present disclosure, "water-soluble" means that insoluble matter is less than 0.5 mass% (less than 2.5 mg) when 0.5 g of the compound is dissolved in 100 g of water at 25 ° C.

((Meth) acrylamide group-containing compound (a): also referred to as (a) component)

In the present disclosure, the term "(meth) acrylamide group-containing compound" means a (meth) acrylamide skeleton

(Wherein R &lt; ^{1 &gt;} is hydrogen or a methyl group)

Or a salt thereof. As the (meth) acrylamide group-containing compound, various known ones may be used alone, or two or more kinds thereof may be used in combination.

In the present disclosure, "(meth) acrylic" means "at least one selected from the group consisting of acrylic and methacrylic". Similarly, "(meth) acrylate" means "at least one selected from the group consisting of acrylate and methacrylate". The term "(meth) acryloyl" means "at least one selected from the group consisting of acryloyl and methacryloyl".

In one embodiment, the (meth) acrylamide group-containing compound has the structure

(Wherein R ¹ is hydrogen or a methyl group, R ² and R ³ are each independently hydrogen, a substituted or unsubstituted alkyl group, an acetyl group, or a sulfonic acid group, or R ² and R ³ together form a cyclic structure R ⁴ and R ⁵ are each independently hydrogen, a substituted or unsubstituted alkyl group, a carboxyl group, a hydroxyl group, an amino group (-NR ^a R ^{b wherein} R ^a and R ^b are each independently hydrogen or a substituted or unsubstituted alkyl group) (The same applies hereinafter)), an acetyl group, and a sulfonic acid group. The substituent of the substituted alkyl group is exemplified by a hydroxyl group, an amino group, an acetyl group, a sulfonic acid group, etc. The group in which R ² and R ³ together form a ring structure is a morpholyl group morpholyl group) and the like)

Lt; / RTI &gt;

Examples of the alkyl group include a straight chain (normal chain) alkyl group, a branched (branched) alkyl group, and a cycloalkyl group.

The straight chain alkyl group is represented by a general formula -C _n H _{2n + 1} (n is an integer of 1 or more). Examples of the straight chain alkyl group include methyl, ethyl, propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl,

The branched alkyl group is a group in which at least one hydrogen of a straight chain alkyl group is substituted with an alkyl group. Examples of the branched alkyl group include a diethylpentyl group, a trimethylbutyl group, a trimethylpentyl group, and a trimethylhexyl group.

Examples of the cycloalkyl group include a monocyclic cycloalkyl group, a crosslinked ring (crosslinked ring) cycloalkyl group, a condensed ring (condensed ring) cycloalkyl group and the like.

In the present disclosure, a monocyclic ring means an annular structure formed by a covalent bond of carbon and having no bridged structure therein. Further, the condensed ring refers to a cyclic structure in which two or more monocycles share two atoms (i.e., only one side of each ring shares (condenses) one another). A bridged ring means a cyclic structure in which two or more monocyclic rings share three or more atoms.

Examples of the monocyclic cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclodecyl group, and a 3,5,5-trimethylcyclohexyl group.

Examples of the bridged ring cycloalkyl group include a tricyclodecyl group, an adamantyl group, and a norbornyl group.

Examples of the condensed ring cycloalkyl group include a bicyclodecyl group and the like.

The (meth) acrylamide group-containing compound (a) may be at least one selected from the group consisting of N-substituted (meth) acrylamide skeleton-containing monomers, N-1 substituted (meth) Acrylamide skeleton-containing monomers, and the like.

Examples of the N-substituted (meth) acrylamide skeleton-containing monomer include (meth) acrylamide, maleic amide and the like.

Examples of the N-1 substituted (meth) acrylamide skeleton-containing monomer include N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, diacetone (meth) acrylamide, Sulfonic acid, hydroxyethyl (meth) acrylamide, and the like.

The N-2 substituted (meth) acrylamide skeleton-containing monomer is preferably at least one monomer selected from the group consisting of N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, (Meth) acryloylmorpholine, and the like.

Examples of the salts include dimethyl quaternary salt of dimethylaminopropyl (meth) acrylamide chloride and quaternary salt of dimethylaminoethyl (meth) acrylate benzyl chloride.

Among (meth) acrylamide group-containing compounds (a), the use of (meth) acrylamides, especially acrylamides, increases water solubility and dispersibility of the slurry. As a result, the binding property between the electrode active materials and the ceramic fine particles becomes high.

The upper limit of the proportion of the constitutional unit derived from the (meth) acrylamide group-containing compound (a) is preferably such that the proportion of the constituent unit derived from the (meth) acrylamide group- And the lower limits are 99.8, 99.7, 99.2, 95, 90, 85, 80, 75, 70, 65, and 60 mol% %. In one embodiment, the proportion of the structural unit derived from the (meth) acrylamide group-containing compound (a) is preferably 60 mol% or more, more preferably 65.0 to 99.8 mol% based on 100 mol% %, And particularly preferably 70.0 to 99.7 mol%. (A) contains a specific amount of the component (A) derived from the (meth) acrylamide group-containing compound (a), the dispersibility of the electrode active material, the filler and the ceramic fine particles becomes good, and the uniform layer (electrode active material layer, Microparticulate layer, etc.) can be produced, so that structural defects are eliminated and good charge / discharge characteristics are exhibited. In addition, since the specific unit derived from the (meth) acrylamide group-containing compound is contained in the component (A), the oxidation resistance and the reduction resistance of the polymer are improved, deterioration at the time of high voltage is suppressed and satisfactory charge- .

The upper limit of the proportion of the structural unit derived from the (meth) acrylamide group-containing compound (a) to 100 mass% of the total structural units in the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) is 99.999, 99.99 , 99.95, 99.9, 99.8, 99.7, 99.2, 95, 90, 85, 80, 75, 70, 65, 55, 50, 45, 40, 35, 30, 25, 20, 15 mass% 99.99, 99.8, 99.7, 99.2, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, And the like. In one embodiment, the ratio of the constituent units derived from the (meth) acrylamide group-containing compound (a) to the total constituent units in the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) Is preferably 10 to 99.999 mass%.

(Double bond-containing trihydroxysilyl compound (b): also referred to as component (b))

2 bond-trihydroxy-silyl compound (b) of the vinyl group or (meth) acrylic lock time, and trihydroxy silyl compound (R-Si (OH) having a group ₃ (R is a vinyl group, or a (meth ) Acrylics). As the double bond-containing trihydroxysilyl compound (b), various known ones may be used alone, or two or more types may be used in combination. The preparation of such a double bond-containing trihydroxysilyl compound (b) is preferably a method of hydrolyzing a silane coupling agent. As the silane coupling agent, various known ones may be used alone, or two or more kinds of silane coupling agents may be used in combination.

Examples of the silane coupling agent having a vinyl group include vinylmethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane and the like.

Also, the silane coupling agent having a (meth) acryloxy group is preferably a silane coupling agent having at least one functional group selected from 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (Meth) acryloxypropyltriethoxysilane, and the like.

Of these silane coupling agents, vinyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane are preferable because hydrolysis can proceed easily. The double bond-containing trihydroxysilyl compound (b) may be partially condensed at the time of hydrolysis within a range that does not lose water solubility.

The production method of the triple bond-containing trihydroxysilyl compound (b) is not particularly limited, but the above silane coupling agent is added to a water or water / alcohol mixed solution, and hydrolysis, partial A method of using a sol solution in which a condensation reaction is carried out, and the like.

When the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) is prepared by using the sol solution,

· Method of mixing (a) components in an aqueous monomer solution

A method of dropping during the polymerization of the component (A)

Is preferable.

The proportion of the constitutional unit derived from the trihydrosiloxy compound (b) in the trihydrosiloxy group-containing poly (meth) acrylamide (A) is not particularly limited. The upper limit of the proportion of the constitutional unit derived from the triple bond-containing trihydroxysilyl compound (b) is 0.80, 0.70, 0.60, 0.50, 0.40, 0.30, 0.20, 0.10 mol% and the like are exemplified, and lower limits are 0.75, 0.70, 0.60, 0.50, 0.40, 0.30, 0.20, 0.10, 0.05 mol% and the like. In one embodiment, the range of the proportion of the structural units derived from the double bond-containing trihydroxysilyl compound (b) is preferably from 0.05 to 0.80 mol% based on 100 mol% of all the structural units in the component (A) , More preferably 0.1 to 0.70 mol%. If it is 0.05 mol% or more, thermal crosslinking between molecules is sufficient. As a result, the battery capacity and spring resistance of the lithium ion battery including the electrode manufactured using the aqueous solution for a lithium ion battery are improved. Also, when the separator is produced using the aqueous solution for a lithium ion battery, the heat shrinkability, dust fall-off proofness, and substrate adhesion of the separator are improved.

The upper limit of the proportion of the constitutional unit derived from the double bond-containing trihydroxysilyl compound (b) in the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) is 10.0, 9, 3, 1, 0.9, 0.5, 0.3, 0.1, 0.09, 0.05, 0.01, 0.009 and 0.005 mass%, and the lower limit is 9, 7, 5, 3, 1, 0.9, 0.5, 0.3, 0.1, 0.09 , 0.05, 0.01, 0.009, 0.005, 0.001 mass%, and the like. In one embodiment, the proportion of the constitutional unit derived from the double bond-containing trihydroxysilyl compound (b) in the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) is 0.001 to 10.0 % By mass is preferable.

(Mass) / (b) of the constituent unit derived from the (meth) acrylamide group-containing compound (a) and the constituent unit derived from the double bond-containing trihydroxy silyl compound (b) And the lower limit is 1900, 1750, 1500, 1250, 1000, 750, 750, 500, 250, 100, 80, 500, 250, 100, 80, 75, and the like. In one embodiment, the ratio of the constituent unit derived from the component (a) to the constituent unit derived from the component (b) (amount of the component (a) / amount of the component (b)) is preferably 75 to 2000 Do.

(also referred to as monomer (a) component: component (c), not component (b)

As the monomer group, a monomer (component (c)) which is neither a component (a) nor a component (b) can be used so long as the desired effect of the present invention is not impaired. As the component (c), various known ones may be used alone, or two or more kinds thereof may be used in combination. Examples of the component (c) include an acid group-containing monomer such as an unsaturated carboxylic acid, an unsaturated sulfonic acid and an unsaturated phosphoric acid, an unsaturated carboxylic acid ester, an?,? -unsaturated nitrile, a conjugated diene and an aromatic vinyl compound.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and salts thereof.

The content of the unsaturated carboxylic acid in 100 mol% of the monomer group is not particularly limited. However, considering the reaction with the component (b), the amount of the unsaturated carboxylic acid is preferably less than 40 mol% (e.g., 30, 20, 19, 15 , 10, 5, less than 1 mol%, 0 mol%).

The upper limit of the content of the unsaturated carboxylic acid in 100 mass% of the monomer group is exemplified by 60, 50, 40, 30, 20, 10, 5, 1 mass% and the lower limit is 50, 40, 30, 20, 5, 1, 0 mass%, and the like. In one embodiment, the content of the unsaturated carboxylic acid relative to 100 mass% of the monomer group is preferably 0.0 to 60 mass%.

Examples of the unsaturated sulfonic acid include α, β-ethylenically unsaturated sulfonic acids such as vinylsulfonic acid, styrenesulfonic acid and (meth) allylsulfonic acid; (Meth) acrylamide t-butylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- - (3-sulfopropyl) itaconic acid ester, salts thereof and the like.

The content of the unsaturated sulfonic acid in 100 mol% of the monomer group is not particularly limited, but considering the reaction with the component (b), the upper limit of the unsaturated sulfonic acid content in the monomer group is preferably 40, 30, And the lower limit is 30, 20, 19, 15, 10, 5, 1, 0.5, 0.1, 0.05, 0.02, 0.01, 0.5, 0.1, 0.05 and 0.02 mol% , 0 mol%, and the like.

The upper limit of the content of the unsaturated sulfonic acid with respect to 100 mass% of the monomer group is exemplified by 70, 60, 50, 40, 30, 20, 10, 5, 1, 0.05, 0.02 and 0.01 mass% 50, 40, 30, 20, 10, 5, 1, 0.05, 0.02, 0.01, 0 mass%. In one embodiment, the content of the unsaturated sulfonic acid with respect to 100 mass% of the monomer group is preferably 0 to 70 mass%.

The unsaturated phosphoric acid monomer is at least one member selected from the group consisting of vinylphosphonic acid, vinyl phosphate, bis ((meth) acryloxyethyl) phosphate, diphenyl- 2- (meth) acryloyloxyethyl phosphate, dibutyl- (Meth) acryloyloxy-2-hydroxypropane phosphoric acid, and their derivatives, such as ethylphosphate, dioctyl-2- (meth) acryloyloxyethylphosphate, Salts and the like.

The content of the acid group-containing monomer such as unsaturated phosphoric acid in 100 mol% of the monomer group is not particularly limited. However, considering the reaction with the component (b), the amount of the acid group-containing monomer is preferably less than 40 mol% 20, 19, 15, 10, 5, less than 1 mol%, 0 mol%).

The upper limit of the content of the acid group-containing monomer such as unsaturated phosphoric acid to 100 mass% of the monomer group is exemplified by 60, 50, 40, 30, 20, 10, 5 and 1 mass%, and the lower limit is 50, 20, 10, 5, 1, 0 mass%, and the like. In one embodiment, the content of the acid group-containing monomer such as unsaturated phosphoric acid relative to 100 mass% of the monomer group is preferably 0 to 60 mass%.

In one embodiment, the total content of the acid group-containing monomers such as unsaturated carboxylic acid, unsaturated sulfonic acid and unsaturated phosphoric acid is less than 40 mol% (for example, 30, 20, 19, 15, 10, Less than 1 mol%, 0 mol%).

The upper limit of the total content of acid group-containing monomers such as unsaturated carboxylic acid, unsaturated sulfonic acid and unsaturated phosphoric acid relative to 100 mass% of the monomer group is 70, 60, 50, 40, 30, 20, 10, 5, 1 mass% , And the lower limit is 60, 50, 40, 30, 20, 10, 5, 1, 0 mass%. In one embodiment, the total content of acid group-containing monomers such as unsaturated carboxylic acid, unsaturated sulfonic acid and unsaturated phosphoric acid relative to 100 mass% of the monomer group is preferably 0 to 70 mass%.

The unsaturated carboxylic acid ester is preferably a (meth) acrylic acid ester. Examples of the (meth) acrylic esters include straight chain (meth) acrylic esters, branched (meth) acrylic acid esters, alicyclic (alicyclic) (meth) acrylic esters and substituted (meth) acrylic esters.

The straight-chain (meth) acrylic acid ester is preferably selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate and decyl (meth) acrylate.

Examples of the branched (meth) acrylic esters include i-propyl (meth) acrylate, i-butyl (meth) acrylate, i-amyl (meth) acrylate and 2-ethylhexyl (meth) acrylate.

Examples of the alicyclic (meth) acrylic esters include cyclohexyl (meth) acrylate and the like.

Examples of the substituted (meth) acrylic acid esters include glycidyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, ethylene glycol (meth) acrylate, (Meth) acrylate, trimethylol propane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, allyl methacrylate and ethylene di (meth) acrylate.

The content of the unsaturated carboxylic acid ester in the monomer group 100 mol% is not particularly limited, but the unsaturated carboxylic acid ester can impart flexibility to the electrode, and is particularly useful when used in a winding type or cylindrical battery. It is useful from the viewpoint that the curl of the separator due to the lowering of the glass transition temperature of the poly (meth) acrylamide (A) containing the water-soluble trihydroxysilyl group can be suppressed. On the other hand, considering the cycle characteristics of the lithium ion battery and the water solubility of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A), the content of the unsaturated carboxylic acid ester in 100 mol% The content of the unsaturated carboxylic acid ester to 100 mol% of the monomer group is preferably 90 mass% or less (for example, 30 mass%, 20 mass%, 20 mass% 80, 70, 60, 50, 40, 30, 20, 19, 15, 10, 5, 1 mass%, 0 mass%).

The?,? - unsaturated nitrile can be suitably used for imparting flexibility to the electrode and the separator. Examples of the?,? -unsaturated nitrile include (meth) acrylonitrile,? -chloro (meth) acrylonitrile,? ethyl (meth) acrylonitrile and vinylidene cyanide. Among them, (meth) acrylonitrile is preferable, and acrylonitrile is particularly preferable.

 The content of?,? - unsaturated nitrile in 100 mol% of the monomer group is not particularly limited, but is preferably less than 40 mol% (for example, 30, 20, 19, 15, 10, 5, 1 mol% , And 0 mol%). When the amount of the component (A) is less than 40 mol% with respect to 100 mol% of the monomer group, the layer (coating layer) of the slurry is uniform and easily exhibits the flexibility while maintaining solubility in water Loses.

The upper limit of the content of?,? - unsaturated nitrile with respect to 100 mass% of the monomer group is exemplified by 60, 50, 40, 30, 20, 10, 5 and 1 mass% and the lower limit is 50, 40, 30 and 20 , 10, 5, 1, 0 mass%, and the like. In one embodiment, the content of?,? - unsaturated nitrile with respect to 100 mass% of the monomer group is preferably 0 to 60 mass%.

The conjugated diene may be selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, Side chain conjugated hexadiene, and the like.

The content of the conjugated diene in 100 mol% of the monomer group is not particularly limited, but is preferably less than 10 mol% and more preferably 0 mol% in 100 mol% of the monomer group from the viewpoint of the cycle characteristics of the lithium ion battery.

The upper limit of the content of the conjugated diene relative to 100 mass% of the monomer group is exemplified by 30, 20, 10, 5, 1 mass% and the lower limit is 20, 10, 5, 1, 0 mass%. In one embodiment, the content of the conjugated diene relative to 100 mass% of the monomer group is more preferably 0 to 30 mass%.

Examples of the aromatic vinyl compound include styrene,? -Methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, and divinylbenzene.

The content of the aromatic vinyl compound in 100 mol% of the monomer group is not particularly limited, but is preferably less than 10 mol%, more preferably 0 mol% in 100 mol% of the monomer group from the viewpoint of cycle characteristics of the lithium ion battery.

The upper limit of the content of the aromatic vinyl compound relative to 100 mol% of the monomer group is exemplified by 30%, 20%, 10%, 5% or 1% by mass, and the lower limit is exemplified by 20%, 10%, 5% or 1% by mass. In one embodiment, the content of the aromatic vinyl compound relative to 100 mass% of the monomer group is preferably 0 to 30 mass%.

The proportion of the monomer groups of component (c) other than the acid group-containing monomers, unsaturated carboxylic acid esters,?,? -Unsaturated nitrile, conjugated dienes and aromatic vinyl compounds, such as unsaturated carboxylic acid, unsaturated sulfonic acid and unsaturated phosphoric acid is preferably 100 mol% %, Less than 10 mol%, less than 5 mol%, less than 2 mol%, less than 1 mol%, less than 0.1 mol%, less than 0.01 mol%, 0 mol% Less than 1% by mass, less than 0.5% by mass, less than 0.1% by mass, less than 0.01% by mass, and 0% by mass.

The upper limit of the content of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) relative to 100 mass% of the slurry was 99.9, 95, 90, 80, 70, 60, 50, 40, 30, 20, 5, 1, 0.5, 0.2 and 0.1 mass%, and the lower limit thereof is 95, 90, 80, 70, 60, 50, 40, 30, . In one embodiment, 0.1 to 99.9% by mass of the component (A) is contained relative to 100% by mass of the slurry.

&Lt; Production method of component (A) >

The component (A) can be synthesized by various known polymerization methods, preferably by radical polymerization. Concretely, it is preferable to add a radical polymerization initiator and, if necessary, a chain transfer agent to the monomer mixture solution containing the above components, and to carry out the polymerization reaction at a reaction temperature of 50 to 100 캜 while stirring. The reaction time is not particularly limited and is preferably 1 to 10 hours.

As the radical polymerization initiator, various known ones are used without particular limitation. Examples of the radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; A redox-type polymerization initiator obtained by combining the persulfate and a reducing agent such as sodium hydrogen sulfite; And azo-based initiators such as 2,2'-azobis-2-amidinopropane dihydrochloride. The amount of the radical polymerization initiator to be used is not particularly limited, but is preferably 0.05 to 5.00 mass%, more preferably 0.1 to 3.0 mass%, based on 100 mass% of the monomer group to which the component (A) is added.

The pH of the reaction solution is adjusted with common neutralizing agents such as ammonia, organic amine, potassium hydroxide, sodium hydroxide and lithium hydroxide for the purpose of improving the production stability before the radical polymerization reaction and / or when the obtained component (A) . In that case, the pH is preferably 2 to 11. For the same purpose, EDTA or a salt thereof, which is a metal ion-sealing agent, may also be used.

When the component (A) is provided with an acid group, the neutralization ratio may be appropriately adjusted depending on the application. Here, the neutralization ratio of 100% indicates neutralization by alkali of the same number of moles as the acid component contained in the component (A). The neutralization rate of 50% indicates that the acid component contained in the component (A) is neutralized by an alkali of about half a mol number. The neutralization ratio when the ceramic fine particles are dispersed is not particularly limited, but the neutralization ratio is preferably 70 to 120%, and the neutralization ratio is more preferably 80 to 120% after formation of the coating layer and the like. When the degree of neutralization after the production of the coating layer is in the above range, most of the acid is neutralized, and it is preferable to combine with Li ions or the like in the battery to reduce the capacity. Examples of neutralized salts include Li salts, Na salts, K salts, ammonium salts, Mg salts, Ca salts, Zn salts, Al salts and the like.

&Lt; Physical properties of component (A) >

The weight average molecular weight (Mw) of the component (A) is not particularly limited, but the upper limit of the weight average molecular weight (Mw) is 6,000,000, 5,550,000, 5,000,000, 4,500,000, 4,000,000, 100,000, 95,000, 900,000, 85,000, 800,000, 750,000, 700,000, 65,000, 600,000, 550,000, 500,000, 450,000, and 400,000 , The lower limit is 550 million, 5 million, 4.5 million, 4 million, 3.5 million, 3 million, 290 million, 2.5 million, 2 million, 1.5 million, 1 million, 95 million, 90 million, 85 million, 80 million, 75 , 700,000, 650,000, 600,000, 550,000, 500,000, 450,000, 400,000, 350,000, and 300,000. In one embodiment, from the viewpoint of dispersion stability of the slurry for a lithium ion battery, the weight average molecular weight (Mw) of the component (A) is preferably 300,000 to 600,000, more preferably 350,000 to 600,000.

The upper limit of the number average molecular weight (Mn) of the component (A) was 600,000, 550,000, 5,000,000, 4,500,000, 4,000,000, 3,500,000, 3,000,000, 2,550,000, 2,000,000, 1,500,000, 800,000, 750,000, 700,000, 650,000, 600,000, 550,000, 500,000, 450,000, 400,000, 300,000, 200,000, 100,000, and 5,000, The lower limit is 550 million, 5 million, 4.5 million, 4 million, 3.5 million, 3 million, 2.9 million, 2.5 million, 2 million, 1.5 million, 1 million, 95 million, 90 million, 85 million, , 700,000, 650,000, 600,000, 550,000, 500,000, 450,000, 400,000, 350,000, 300,000, 200,000, 100,000, 50,000, and 10,000. In one embodiment, the number average molecular weight (Mn) of the component (A) is preferably 10,000 or more.

The weight-average molecular weight and the number-average molecular weight can be determined, for example, by gel permeation chromatography (GPC) as a polyacrylic acid-equivalent value measured under an appropriate solvent.

The B-type viscosity of the component (A) is not particularly limited, but the upper limit is 100,000, 90,000, 80,000, 70,000, 60,000, 50,000, 40,000, 30,000, 20,000, , 8000, 7000, 6000, 5000, 4000, 3000 and 2000 mPa · s, and the lower limit is 90,000, 80,000, 70,000, 60,000, 50,000, 40,000, 30,000, , 9000, 8000, 7000, 6000, 5000, 4000, 3000, 2000, 1000 mPa s. In one embodiment, the range of the B-type viscosity of the component (A) is preferably from 1,000 to 100,000 mPa · s. The B-type viscosity is measured by a B-type viscometer such as "B-type Viscometer Model BM" manufactured by Toki Sangyo Co., Ltd.

The gel fraction of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) is not particularly limited, but the upper limit of the gel fraction of the component (A) is 99.9%, 95%, 90% %, 75%, 70%, 65%, 60% and the lower limit is 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55% . In one embodiment, the gel fraction of component (A) is preferably at least 50%, more preferably at least 55%. The gel fraction means a gel fraction expressed by the following formula

Gel fraction (%) = (insoluble residue in solution (g) / mass of solid in solution (g)) x 100

.

The pH of the aqueous solution containing the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) is not particularly limited, but is preferably pH 2 to 13 (25 ° C) from the viewpoint of solution stability, desirable.

<Additives>

The binder aqueous solution for a lithium ion battery may contain, as an additive, an ingredient (A) which does not correspond to water. Examples of additives include dispersants, leveling agents, antioxidants, thickeners, dispersions (emulsions) and the like. The content of the additive is 0 to 5% by mass, less than 1% by mass, less than 0.1% by mass, less than 0.01% by mass and 0% by mass with respect to 100% by mass of the component (A) By mass, less than 1% by mass, less than 0.1% by mass, less than 0.01% by mass, 0% by mass, and the like.

Examples of the dispersing agent include anionic compounds, cationic compounds, nonionic compounds, and polymer compounds.

Examples of the leveling agent include surfactants such as alkyl type surfactants, silicone type surfactants, fluorine type surfactants, and metal type surfactants. By using a surfactant, it is possible to prevent slippage during coating and to improve the smoothness of the layer (coating layer) of the slurry.

Examples of the antioxidant include phenol compounds, hydroquinone compounds, organic phosphorus compounds, sulfur compounds, phenylenediamine compounds, and polymer-type phenol compounds. The polymer type phenol compound is a polymer having a phenol structure in its molecule. The weight average molecular weight of the polymer type phenolic compound is preferably 200 to 1000, more preferably 600 to 700.

Examples of the thickener include cellulose polymers such as carboxymethylcellulose, methylcellulose, and hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof; (Modified) poly (meth) acrylic acid and ammonium salts and alkali metal salts thereof; (Denatured) polyvinyl alcohol, copolymers of acrylic acid or acrylic acid salts with vinyl alcohol, polyvinyl alcohols such as maleic anhydride or maleic acid, or copolymers of fumaric acid and vinyl alcohol; Polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, modified polyacrylic acid, starch oxide, starch phosphate, casein, various modified starches, and acrylonitrile-butadiene copolymer hydrides.

The dispersion (emulsion) may be at least one selected from the group consisting of styrene-butadiene copolymer latex, polystyrene polymer latex, polybutadiene polymer latex, acrylonitrile-butadiene copolymer latex, polyurethane- Methyl methacrylate-butadiene copolymer latex, polyacrylate-based polymer latex, vinyl chloride polymer latex, vinyl acetate polymer emulsion, vinyl acetate-ethyl copolymer emulsion, polyethylene emulsion, carboxy modified styrene butadiene copolymer resin emulsion, Acrylic resin emulsion, polyethylene, polypropylene, polyethylene terephthalate, polyamide (PA), polyimide (PI), polyamideimide (PAI), aromatic polyamide, alginic acid and its salt, polyvinylidene fluoride Tetrafluoro (TFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE) .

When a separator is produced using a binder aqueous solution for a lithium ion battery, a crosslinking agent may be included as an additive. The crosslinking agent may be at least one selected from the group consisting of formaldehyde, glyoxal, hexamethylenetetramine, urea formaldehyde resin, methylol melamine resin, carbodiimide compound, polyfunctional epoxy compound, oxazoline compound, polyfunctional hydrazide compound, isocyanate compound, Urea compounds and mixtures thereof are exemplified.

The aqueous binder solution for a lithium ion battery can be used as a binder aqueous solution for a lithium ion battery electrode, a binder aqueous solution for a lithium ion battery negative electrode, a binder aqueous solution for a lithium ion battery positive electrode, and a binder aqueous solution for a lithium ion battery separator.

[2. Slurry for lithium ion battery: also called slurry]

The present disclosure relates to a resin composition comprising 60 mol% or more of a (meth) acrylamide group-containing compound (a) relative to 100 mol% of a monomer group and a trihydrosiloxane compound having a vinyl group or (meth) (A) comprising a water-soluble trihydroxy silyl group-containing poly (meth) acrylamide, which is a polymer of a monomer group containing 0.05 to 0.80 mol% of a poly (meth) acrylamide.

In the present disclosure, &quot; slurry &quot; means a suspension of liquid and solid particles.

The slurry for lithium ion batteries may contain a binder other than the component (A), but the content of the component (A) in the total binder is 90 mass% or more (for example, 91, 95, 98, 99 mass% Or more and 100 mass%).

The binder other than the component (A) may be used alone or in combination of two or more. Examples of the binder include a fluororesin (polyvinylidene fluoride, polytetrafluoroethylene and the like), a polyolefin (polyethylene and polypropylene) (Styrene / butadiene rubber, isoprene rubber, butadiene rubber, etc.), acrylic acid polymer (acrylic acid copolymer, methacrylic acid copolymer), carboxymethylcellulose salt, polyvinyl alcohol copolymer, polyvinylpyrrolidone .

<Trihydroxy silyl compound, tetrahydroxy silyl compound>

The stability of the aqueous solution or slurry can be amplified by further containing a trihydroxy silyl compound and / or a tetrahydroxy silyl compound (Si (OH) ₄ ) in the binder aqueous solution for the lithium ion battery or the slurry for the lithium ion battery.

In one embodiment, the trihydroxy silyl compound is represented by the following general formula

RSi (OH) ₃

(Wherein R represents a substituted or unsubstituted alkyl group, a vinyl group or a (meth) acryloxy group, and examples of the substituent include an amino group, a mercapto group, a glycidoxy group, a (meth) acryloyl group, do)

&Lt; / RTI &gt;

Trialkoxysilane is preferably selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N- Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane , 3-isocyanatopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltri Methoxy silane, and tetrahydroxy silyl compounds.

Examples of the tetraalkoxysilane include tetramethoxysilane, tetramethoxysilane oligomer, tetraethoxysilane, tetraethoxysilane oligomer and the like.

Among them, it is preferable to prepare a trihydroxy silyl compound using 3-aminopropyltrimethoxysilane from the viewpoints of stability with the water-soluble polymer (A) and electrolytic solution resistance (electrolytic solution resistance).

In order to stabilize the silanol groups present in these trihydroxy silyl compounds and tetrahydroxy silyl compounds, it is preferable to use water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) and / It is preferable to adjust the pH of the slurry to a certain range. The suitable pH range depends on the silane coupling agent which is the raw material of the hydroxy silyl compound.

Aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) The preferred range of the pH in the silane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidenepropylamine) Or from 9 to 12 in terms of the stability of the slurry for a lithium ion battery.

Further, there may be mentioned N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, Propyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Propyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tetrahydroxy silyl compound, tetramethoxysilane, tetramethoxysilane oligomer, tetraethoxysilane, and tetraethoxysilane oligomer of the above-mentioned suitable pH The range is from pH 2 to 6 in view of the stability of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) or the slurry for a lithium ion battery.

The production method of the trihydroxy silyl compound and the tetrahydroxy silyl compound is not particularly limited, but the above-mentioned silane coupling agent is added to a water or water-alcohol mixed solution, and the hydrolysis and the partial condensation reaction are carried out until homogeneous And a method of using the advanced sol solution.

When preparing the slurry for a lithium ion battery using the sol solution, the sol solution

(Meth) acrylamide group-containing compound (a) in a monomer aqueous solution

A method of mixing the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) aqueous solution after preparation

A method of dispersing an electrode active material (B) or ceramic fine particles (C) in an aqueous solution of a water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A)

Is preferable.

When the slurry contains a trihydroxy silyl compound and / or a tetrahydroxy silyl compound, the upper limit of the content of the trihydroxy silyl compound and / or the tetrahydroxy silyl compound is preferably 100 mass% And the lower limit is 14, 12, 10, 9, 5, 3, 1, 0.9, 0.6, 0.5 Mass% and the like. In one embodiment, the content of the trihydroxy silyl compound and / or the tetrahydroxy silyl compound is preferably from 0.5 to 15 mass%, more preferably from 0.5 to 15 mass% with respect to 100 mass% of the slurry for a lithium ion battery, By mass to 10% by mass, more preferably from 0.5% by mass to 15% by mass with respect to 100% by mass of the component (A), more preferably from 1% by mass to 10% Or from 0.5 to 15 mass% with respect to 100 mass% of the component (C), and more preferably from 1 to 10 mass% from the viewpoint of the effect of addition and the like.

Hereinafter, a mechanism is described in which stability is improved when an aqueous solution or slurry contains a trihydroxy silyl compound and / or a tetrahydroxy silyl compound. However, as an explanation only, the present invention is not limited thereto It is not intended to be.

mechanism

A large number of silanol groups are produced by hydrolysis of the alkoxysilanes. The silanol group (SiOH) is an equilibrium reaction with a siloxane bond (Si-O-Si), and some siloxane bonds are present. In the binder aqueous solution for a lithium ion battery or the slurry for a lithium ion battery, most of them are present as a silanol group, and thus exhibit storage stability or slurry stability of an aqueous solution.

&Lt; Electrode active material (B): also referred to as component (B)

In one embodiment, the slurry for a lithium ion battery includes an electrode active material (B). Examples of the electrode active material include a negative electrode active material and a positive electrode active material.

The negative electrode active material is not particularly limited as long as it is capable of reversibly absorbing and releasing lithium and can suitably be selected depending on the type of the lithium ion battery to be used. Two or more kinds may be used together. Examples of the negative electrode active material include a carbon material and a material which is alloyed with lithium, such as a silicon material, an oxide containing lithium atom, a lead compound, a tin compound, an arsenic compound, an antimony compound and an aluminum compound.

The carbon material may be graphite (graphite, natural graphite, artificial graphite or the like is exemplified as high crystalline carbon), low crystalline carbon (soft carbon, hard carbon), carbon black (ketjen black, acetylene black (Eg, channel black, lamp black, oil furnace black, thermal black), fullerene, carbon nanotubes, carbon nanofibers, carbon nanofines, carbon fibrils, Meso-carbon microbeads (MCMB), pitch-based carbon fibers, and the like.

The silicone material is, in addition to silicon, silicon oxide, a silicon _{alloy, SiC, SiO x C y (} 0 <x≤3, 0 <y≤5), Si 3 N 4, Si 2 N 2 O, SiO x (0 <x? 2) (for example, the materials described in Japanese Patent Application Laid-Open No. 2004-185810 and Japanese Patent Application Laid-Open No. 2005-259697), Japanese Laid- And silicone materials described in JP-A-2004-185810. The silicon material described in Japanese Patent No. 5390336 or Japanese Patent No. 5903761 may also be used.

The silicon oxide is preferably a silicon oxide represented by the composition formula SiOx (0 < x < 2, preferably 0.1 x 1).

The silicon alloy is preferably an alloy of silicon and at least one transition metal selected from the group consisting of titanium, zirconium, nickel, copper, iron and molybdenum. Silicon alloys of these transition metals are preferred because they have high electronic conductivity and high strength. The silicon alloy is more preferably a silicon-nickel alloy or a silicon-titanium alloy, and a silicon-titanium alloy is particularly preferable. The content of silicon in the silicon alloy is preferably 10 mol% or more, and more preferably 20 mol% to 70 mol%, based on 100 mol% of the metal element in the alloy. The silicon material may be a single crystal, a polycrystal, or an amorphous material.

When a silicon material is used as the electrode active material, an electrode active material other than the silicon material may be used in combination. Such an electrode active material includes the carbon material described above; Conductive polymers such as polyacene; A _X B _Y O _{Z wherein} A is an alkali metal or a transition metal, B is at least one selected from transition metals such as cobalt, nickel, aluminum, tin and manganese, O is an oxygen atom, X, Y and Z are Are numbers in the range of 0.05 <X <1.10, 0.85 <Y <4.00, and 1.5 <Z <5.00, respectively), and other metal oxides. In the case of using a silicon material as the electrode active material, it is preferable to use a carbon material in combination because the volume change due to insertion and extraction of lithium is small.

Oxide containing the lithium atom, a ternary nickel-cobalt lithium manganese oxide, lithium-manganese composite oxide (LiMn ₂ O ₄ and the like), lithium-nickel composite oxide (LiNiO ₂ and the like), lithium-cobalt composite oxide (LiCoO _2, etc. ), A lithium-iron composite oxide (such as LiFeO ₂ ), a lithium-nickel-manganese composite oxide (LiNi _0.5 Mn _0.5 O ₂ and the like), a lithium-nickel-cobalt composite oxide (LiNi _0.8 Co _0.2 O ₂ , A transition metal complex oxide such as a metal phosphate compound (LiFePO ₄ ), a lithium-transition metal sulfate compound (LixFe ₂ (SO ₄ ) ₃ ), and a lithium-titanium composite oxide (lithium titanate: Li ₄ Ti ₅ O ₁₂ ) And other conventionally known electrode active materials.

From the viewpoint that the effect of the present invention is remarkably exerted, it is preferable that the carbon material and / or the material which alloys with lithium are contained in the electrode active material in an amount of preferably 50 mass% or more, more preferably 80 mass% or more, % Or more, particularly preferably 100 mass% or more.

The positive electrode active material is broadly divided into an active material containing an inorganic compound and an active material containing an organic compound. Examples of inorganic compounds contained in the positive electrode active material include transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides. Examples of the transition metal include Fe, Co, Ni, Mn, Al and the like. The inorganic compound used for the positive electrode active material may be LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , LiNi _1/2 Mn _3/2 O ₄ , LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , Li [Li _0.1 Al _0.1 Mn _1.9 ] O ₄ , and LiFeVO ₄ ; Transition metal sulfides such as TiS ₂ , TiS ₃ and amorphous MoS ₂ ; Transition metal oxides such as Cu ₂ V ₂ O ₃ , amorphous V ₂ O-P ₂ O ₅ , MoO ₃ , V ₂ O ₅ and V ₆ O ₁₃ . These compounds may be partially substituted by an element. Examples of the organic compound contained in the positive electrode active material include conductive polymers such as polyacetylene and poly-p-phenylene. The iron-based oxide lacking electric conductivity may be used as an electrode active material covered with a carbon material by causing a carbon source material to exist at the time of reduction calcination. These compounds may be partially substituted by elements. Of these, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ OLiFePO ₄ , LiNi _1/2 Mn _3/2 O ₄ , LiCo _1/3 Ni _1/3 Mn _1/3 in terms of practicality, electrical characteristics, O ₂ , and Li [Li _0.1 Al _0.1 Mn _1.9 ] O ₄ are preferable.

The shape of the electrode active material is not particularly limited and may be any shape such as a fine particle shape or a thin film shape, but is preferably a fine particle shape. The average particle diameter of the electrode active material is not particularly limited, but the upper limit thereof is 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 4, 3, 2.9, And the lower limit is 45, 40, 35, 30, 25, 20, 15, 10, 5, 4, 3, 2.9, 2, 1, 0.5, 0.1 탆 and the like. In view of forming a uniformly thin coating film in one embodiment, more specifically, the handling property is better when the thickness is 0.1 占 퐉 or more, and the electrode is easily coated when the thickness is 50 占 퐉 or less. More preferably 0.1 to 45 占 퐉, more preferably 1 to 10 占 퐉, and particularly preferably 5 占 퐉.

In the present disclosure, the &quot; particle diameter &quot; means the maximum distance among arbitrary two points on the contour of the particle (the same shall apply hereinafter). In the present disclosure, "average particle diameter" means a particle diameter of particles observed in a few to several decades, using observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM) A value calculated as an average value of diameters is adopted (the same shall apply hereinafter).

The upper limit of the content of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) relative to 100 mass% of the electrode active material (B) in the slurry is 15, 14, 13, 12, 11, 8, 7, 6, 5, 4, 6, 5, 4, 3, 2 and 1.5 mass%, and the lower limit is 14, 13, 12, 11, 10, 9, 2, 1.5, 1% by mass, and the like. In one embodiment, the content of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) relative to 100 mass% of the electrode active material (B) is preferably 1 to 15 mass%.

In one embodiment, the content of silicon or silicon oxide in the electrode active material is 20% by mass or more (for example, 30% by mass or more, more preferably 30% by mass or more) based on 100% by mass of the electrode active material from the viewpoint of increasing the battery capacity of the lithium- More preferably 40 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 100 mass%).

In one embodiment, a conductive auxiliary may be included in the slurry. The conductive auxiliary agent may be selected from fibrous carbon such as vapor grown carbon fiber (VGCF), carbon nanotube (CNT) and carbon nanofiber (CNF), carbon black such as graphite particles, acetylene black, ketjen black and furnace black, (Fine powder) of Cu, Ni, Al, Si, or an alloy thereof. The content of the conductive auxiliary agent is not particularly limited, but is preferably 0 to 10% by mass, more preferably 0.5 to 6% by mass based on the electrode active material component.

&Lt; Ceramic fine particles (C): also referred to as component (C)

In one embodiment, the slurry for a lithium ion battery includes ceramic fine particles (C). The ceramic fine particles are components coated on the active material side of a porous polyolefin resin base material, a plastic nonwoven fabric, and an electrode material, and a gap between these ceramic fine particles can form holes. Since the ceramic fine particles have non-conductive property, they can be made insulating, and short-circuiting of the lithium ion battery can be prevented. In addition, since the ceramic fine particles usually have high rigidity, the mechanical strength of the separator for a lithium ion battery can be increased. Therefore, even when a stress to be shrunk to the porous polyolefin resin base material or the plastic nonwoven fabric by heat is generated, the lithium ion battery separator can withstand the stress. As a result, it is possible to prevent short-circuiting caused by contraction of the porous polyolefin resin base material and the plastic nonwoven fabric.

By using the ceramic fine particles, the dispersion stability in water is excellent, so that it is difficult to precipitate in the slurry for a lithium ion battery, and a uniform slurry state can be maintained for a long time. If ceramic fine particles are used, the heat resistance can be increased. The ceramic fine particles may be used singly or in combination of two or more kinds.

The material of the ceramic fine particles is preferably an electrochemically stable material. In this respect, the ceramic fine particles include oxide particles, nitride particles, covalent bonding crystal particles, poorly soluble ionic crystal particles, fine clay particles, and the like.

The oxide particles are preferably selected from the group consisting of aluminum oxide (alumina), hydrated aluminum oxide (boehmite (AlOOH), gibbsite (Al (OH) ₃ ), bakelite, iron oxide, silicon oxide, magnesium oxide (magnesia), magnesium hydroxide, calcium oxide, titanium oxide (titania), BaTiO _3, ZrO, alumina oxide-silica composite oxide and the like or the like.

Examples of the nitride particles include aluminum nitride, silicon nitride, and boron nitride.

Examples of the covalent bonding crystal particles include silicon, diamond and the like.

Examples of the poorly soluble ionic crystal grains are barium sulfate, calcium fluoride, barium fluoride and the like.

Examples of the clay fine particles include silica, talc, montmorillonite, and other clay fine particles.

Of these, boehmite, alumina, magnesium oxide and barium sulfate are preferable, and boehmite is more preferable from the viewpoint of low water absorption and excellent heat resistance.

The upper limit of the average particle size of the ceramic fine particles is 30, 25, 20, 15, 10, 5, 1, 0.5, 0.1, 0.05 탆 and the lower limit is 25, 20, 15, 10, 5, 0.5, 0.1, 0.05, 0.01 占 퐉 and the like are exemplified. In one embodiment, the average particle diameter of the ceramic fine particles is preferably 0.01 to 30 mu m.

The upper limit of the content of the ceramic fine particles (C) relative to 100 mass% of the slurry was 99.9, 95, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 1, 0.5, 0.2 mass% And the lower limit is 95, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 1, 0.5, 0.2, 0.1 mass% and the like. In one embodiment, 0.1 to 99.9 mass% of the ceramic fine particles (C) is contained relative to 100 mass% of the slurry.

The upper limit of the content of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) relative to 100 mass% of the ceramic fine particles (C) in the slurry is 15, 14, 13, 12, 11, 8, 7, 6, 5, 4, 6, 5, 4, 3, 2 and 1.5 mass%, and the lower limit is 14, 13, 12, 11, 10, 9, 2, 1.5, 1% by mass, and the like. In one embodiment, the content of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) relative to 100 mass% of the ceramic fine particles (C) is preferably from 1 to 15 mass%, more preferably from 1.5 to 14 mass% , More preferably from 2 to 12 mass%. With such a content, a lithium ion battery separator having better adhesion and smaller resistance and better charging / discharging characteristics can be produced.

&Lt; Slurry viscosity adjusting solvent &

The slurry viscosity adjusting solvent is not particularly limited, but may include a non-aqueous medium (aqueous non-medium) having a standard boiling point of 80 to 350 캜. The slurry viscosity adjusting solvent may be used alone or in combination of two or more. Examples of the slurry viscosity adjusting solvent include amide solvents such as N-methylpyrrolidone, dimethylformamide and N, N-dimethylacetamide; Hydrocarbon solvents such as toluene, xylene, n-dodecane, tetralin and the like; Alcohol solvents such as methanol, ethanol, 2-propanol, isopropyl alcohol, 2-ethyl-1-hexanol, 1-nonanol, and lauryl alcohol; Ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, phorone, acetophenone, and isophorone; Ether solvents such as dioxane and tetrahydrofuran (THF); Ester solvents such as benzyl acetate, isopentyl butyrate, methyl lactate, ethyl lactate and butyl lactate; amine solvents such as o-toluidine, m-toluidine, and p-toluidine; lactones such as? -butyrolactone and? -butyrolactone; Sulfoxide-sulfone solvents such as dimethyl sulfoxide and sulfolane; Water and the like. Of these, N-methylpyrrolidone is preferable from the viewpoint of coating workability. The content of the nonaqueous medium is not particularly limited, but is preferably 0 to 10% by mass based on 100% by mass of the slurry.

The slurry may contain the components (A), (B), (C), a trihydroxy silyl compound, a tetrahydroxy silyl compound, water, a conductive additive, a slurry viscosity And an adjusting solvent which does not correspond to either of them can be included as an additive. Examples of the additive include those described above (described above) in the item of &quot; aqueous binder aqueous solution for lithium ion battery &quot;. The content of the additive is 0 to 5 mass%, less than 1 mass%, less than 0.1 mass%, less than 0.01 mass%, and 0 mass% with respect to 100 mass% of the component (A) 0 to 5% by mass, less than 1% by mass, less than 0.1% by mass, less than 0.01% by mass, and 0% by mass with respect to 100% by mass of component (C).

The slurry for the lithium ion battery can be used as a slurry for a lithium ion battery electrode, a slurry for a lithium ion battery negative electrode, a slurry for a lithium ion battery positive electrode, and a slurry for a lithium ion battery separator.

[3. Manufacturing method of slurry for lithium ion battery]

The present disclosure relates to a resin composition comprising 60 mol% or more of a (meth) acrylamide group-containing compound (a) relative to 100 mol% of a monomer group and a trihydrosiloxane compound having a vinyl group or (meth) (Meth) acrylamide (A) containing a water-soluble trihydroxy silyl group, which is a polymer of a monomer group containing from 0.05 to 0.80 mol% of the poly (meth) acrylamide do. Examples of the component (A) described in this item include the above-mentioned components and the like.

The method for producing the slurry includes a method of mixing an aqueous solution of the component (A) with components other than the component (A) (the electrode active material (B) or the ceramic fine particles (C) (Electrode active material (B), ceramic fine particles (C), etc.) and water are mixed with each other. The order of mixing in the above method is not particularly limited. Examples of the mixing means of the slurry include a ball mill, a sand mill, a pigment disperser, a brain ball (a grinder), an ultrasonic disperser, a homogenizer, a planetary mixer, a Hobart mixer and the like.

[4. Electrode for lithium ion battery]

The present disclosure provides an electrode for a lithium ion battery having a slurry for a lithium ion battery obtained by applying the slurry for a lithium ion battery to a current collector and drying the slurry for a lithium ion battery on the surface of the current collector.

As the current collector, various known ones can be used without particular limitation. The material of the current collector is not particularly limited, and examples thereof include metal materials such as copper, iron, aluminum, nickel, stainless steel and nickel plated steel, and carbon materials such as carbon cloth and carbon paper. The shape of the current collector is not particularly limited, and examples of the metallic material include a metal foil, a metal cylinder, a metal coil, and a metal plate, and in the case of a carbon material, a carbon plate, a carbon thin film and a carbon cylinder. Among them, when an electrode active material is used for a negative electrode, a copper foil is preferably used as a current collector in current industrial products.

The application means is not particularly limited, and conventionally known coating apparatuses such as a comma coater, a gravure coater, a micro gravure coater, a die coater, and a bar coater are exemplified.

The drying means is not particularly limited, and the temperature is preferably 60 to 200 占 폚, more preferably 100 to 195 占 폚. The atmosphere may be dry air or an inert atmosphere.

The thickness of the electrode (cured coating film) is not particularly limited, but is preferably 5 to 300 占 퐉, more preferably 10 to 250 占 퐉. With the above range, the function of storing and discharging Li sufficiently for a high-density current value can be easily obtained.

Hereinafter, a mechanism for sustaining a stable battery capacity and exhibiting spring resistance when manufactured using an aqueous solution or slurry containing the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) is described. As a single description, the present invention is not intended to be bound by this.

mechanism

When the slurry is applied and dried, water is volatilized, and the chemical equilibrium between the silanol group and the siloxane bond shifts greatly to the siloxane bond generation side. At this time, a strong hydrogen bonding interaction occurs between the silanol groups present in the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) and the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide A) three-dimensional cross-linking between chains to form a polyacrylamide-polysiloxane complex. That is, it is present stably in the slurry for a lithium ion battery, forms a siloxane bond when the slurry is coated and dried by heating, and plays a role of crosslinking the binder. This crosslinking structure leads to the effect of cycle characteristics and spring-back resistance. Therefore, even under an environment in which the volume of the electrode active material changes due to the entry and exit of lithium ions in the charge-discharge cycle, stable battery capacity and spring-back are possible.

At the same time, the silanol group of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) acts on the surface of the current collector to exhibit a strong binding force. As a result, even under an environment in which the volume of the electrode active material changes due to the entry and exit of lithium ions in the charge-discharge cycle, it is possible to maintain the stable battery capacity and to increase the spring-back resistance.

The electrode for a lithium ion battery can be used as a positive electrode for a lithium ion battery and a negative electrode for a lithium ion battery.

[5. Separator for lithium ion battery]

The present disclosure relates to a separator for a lithium ion battery comprising a porous polyolefin resin base material or a surface of a plastic nonwoven fabric, wherein the dried product of the lithium ion battery slurry obtained by applying the lithium ion battery slurry to a porous polyolefin resin base material or a plastic non- Lt; / RTI &gt; The slurry for the lithium ion battery may be applied to only one side of the base material or may be applied to both sides of the base material.

The separator for a lithium ion battery has a crosslinked structure formed by a cross-linking reaction of a water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) and ceramic fine particles (C), whereby heat resistance, shrink resistance, Rate characteristics, and output characteristics.

(Porous polyolefin resin base material)

In one embodiment, the substrate is preferably a porous film having no ionic conductivity, high ionic conductivity, high resistance to organic solvents, and a small pore diameter. As such a porous film, there is a porous polyolefin resin substrate. The porous polyolefin resin base material is a microporous film containing a resin such as polyolefin and a mixture or copolymer thereof as a main component. The porous polyolefin resin base material is excellent in the coating ability of the coating liquid when the polymer layer is obtained through the coating process and the thickness of the separator is made thinner to increase the active material ratio in the lithium ion battery so as to increase the capacity per volume desirable. The term &quot; included as the main component &quot; means that the content includes more than 50 mass%, preferably 75 mass% or more, more preferably 85 mass% or more, furthermore preferably 90 mass% 95% by mass or more, particularly preferably 98% by mass or more and 100% by mass.

In one embodiment, the content of the polyolefin resin in the porous polyolefin resin base material is not particularly limited, but from the standpoint of shutdown performance when used as a separator for a lithium ion battery, the content of the polyolefin resin in the porous polyolefin resin base material The content of the polyolefin resin is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% Is more preferable.

The polyolefin resin is not particularly limited, but may be a polyolefin resin used for extrusion, injection, inflation, blow molding, etc., and may be used alone or in combination of two or more. Examples of the polyolefin resin include homopolymers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, copolymers and multistage polymers. The polymerization catalyst used in the production of these polyolefin resins is not particularly limited, and examples thereof include Ziegler-Natta catalyst, Phillips-based catalyst and metallocene-based catalyst.

The polyolefin resin used as the material of the porous polyolefin resin base material is preferably a resin mainly composed of high-density polyethylene because of its low melting point and high strength. From the viewpoint of improving the heat resistance of the polyolefin porous substrate, it is more preferable to use polypropylene and a porous polyolefin resin substrate including a polyolefin resin other than polypropylene.

Here, the steric structure of the polypropylene is not limited, and may be any of isotactic PP, syndiotactic PP, and atactic PP.

The ratio of polypropylene to the total amount of the polyolefin (total amount) contained in the polyolefin resin composition is not particularly limited, but is preferably from 1 to 35 mass%, more preferably from 3 to 20 mass%, from the viewpoint of compatibility between heat resistance and a good shutdown function. , More preferably from 4 to 10 mass%.

In this case, the polyolefin resin other than polypropylene is not limited, and examples thereof include homopolymers or copolymers of olefinic hydrocarbons such as ethylene, 1-butene, 4-methyl-1-pentene, . Specifically, examples of the polyolefin resin other than polypropylene include polyethylene, polybutene, ethylene-propylene random copolymer and the like.

As the polyolefin resin other than polypropylene, polyolefin such as low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultrahigh molecular weight polyethylene and the like, which is a polyolefin resin, Is preferably used. Of these, polyethylene having a density of 0.93 g / cm ³ or more measured according to JIS K 7112 is more preferable from the viewpoint of strength.

The porous polyolefin resin substrate may contain a filler or a fiber compound for the purpose of controlling strength, hardness and heat shrinkage. The surface of a porous polyolefin resin substrate is previously coated with a low molecular compound or a polymer compound for the purpose of improving the adhesion with the adhesive layer or lowering the surface tension with the electrolyte solution to improve the impregnation property of the liquid, , Plasma treatment such as electron pre-treatment such as ultraviolet rays, corona discharge plasma gas, or the like may be performed. Particularly, it is possible to coat with a polymer compound containing a polar group such as a carboxylic acid group, a hydroxyl group and a sulfonic acid group in view of easy impregnation with the coating layer obtained by coating and drying the slurry on the substrate, desirable.

The thickness of the porous polyolefin resin base material is not particularly limited, but is preferably 2 占 퐉 or more, more preferably 5 占 퐉 or more, more preferably 100 占 퐉 or less, more preferably 60 占 퐉 or less and still more preferably 50 占 퐉 or less. It is preferable to adjust the thickness to 2 탆 or more from the viewpoint of improving mechanical strength. On the other hand, adjusting the film thickness to 100 占 퐉 or less is preferable because the volume occupied by the separator in the battery is reduced, which tends to be advantageous in terms of high capacity of the battery.

(Nonwoven fabric made of plastics)

In one embodiment, the average fiber diameter of the nonwoven fabric made of plastic for use in the lithium ion battery separator is preferably 1 to 15 占 퐉, more preferably 1 to 10 占 퐉, from the viewpoint of the adhesion with the nonwoven fabric and the thickness of the separator .

In one embodiment, the average pore diameter of the plastic nonwoven fabric is preferably 1 to 20 占 퐉, more preferably 3 to 20 占 퐉, and further preferably 5 to 20 占 퐉. If the average pore diameter is less than 1 mu m, the internal resistance becomes large and the output characteristics become poor. On the other hand, when the average pore diameter is 20 m or more, the lithium secondary battery may be internally short-circuited when lithium dendrite is generated.

In the present disclosure, the pore diameter means the interval between the synthetic fibers forming the nonwoven fabric made of plastic. The average fiber diameter means an average value of the fiber diameters of 20 randomly selected fibers measured from a scanning electron microscope photograph. Similarly, the average pore diameter means the average value of the pore diameters of twenty randomly selected fibers measured from the pore diameters of the fibers from a scanning electron micrograph.

It is preferable that the nonwoven fabric be composed of only synthetic fibers having an average fiber diameter of 1 to 10 mu m and an average pore diameter of 1 to 20 mu m. However, when the necessity to reduce the thickness of the separator is not so high, Fiber diameter and pore diameter may be used in combination with synthetic fibers different from the above. In addition, from the same viewpoint, fibers other than synthetic fibers may be suitably used in combination. When these fibers (fibers other than synthetic resin fibers and synthetic fibers outside the range specified by the present invention in terms of average fiber diameter and average pore diameter) are used in combination, the content thereof is preferably 30% by mass or less from the viewpoint of securing the strength and the like of the nonwoven fabric By mass, more preferably not more than 20% by mass, and further preferably not more than 10% by mass.

The synthetic resin to be the material of the synthetic resin fiber is selected from the group consisting of a polyolefin resin, a polyester resin, a polyvinyl acetate resin, an ethylene-vinyl acetate copolymer resin, a poly A polyvinyl chloride resin, a polyvinyl ether resin, a polyvinylketone resin, a polyvinyl chloride resin, a polyvinyl chloride resin, a polyvinyl chloride resin, ) -Based resin, a polyether-based resin, a polyvinyl alcohol-based resin, a diene-based resin Resin, a polyurethane resin, a phenol resin, a melamine resin, a furan resin, a urea resin, an aniline resin, an unsaturated polyester resin, A resin, an alkyd resin, a fluorocarbon resin, a silicone resin, a polyamide imide resin, a polyphenylene sulfide resin, a polyimide resin, A polycarbonate resin, a polyazomethine resin, a polyesteramide resin, a polyether ether resin, A polyetheretherketone resin, a poly-p-phenylenebenzobisoxazole resin, a polybenzimidazole resin, an ethylene-vinyl alcohol copolymer resin, And the like. Among them, a polyester resin, an acrylonitrile resin, and a polyolefin resin are preferable in order to improve the adhesion with the ceramic fine particles. When a polyester resin, an acrylic resin or a polyamide resin is used, the heat resistance of the separator can be improved.

The polyester-based resin may be at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PPT), polyethylene naphthalate, PEN, polybuthylene naphthalate, polyethylene isonaphthalate, and fully aromatic polyester. The resin may be used alone or in combination of two or more. Derivatives of these resins can also be used. Among these resins, a polyethylene terephthalate-based resin is preferable in order to improve heat resistance, electrolyte-resistance, and adhesion to ceramic fine particles.

The acrylonitrile-based resin may be one comprising a polymer of 100% acrylonitrile, a copolymer of (meth) acrylic acid derivatives such as acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester to acrylonitrile, Water and the like.

Examples of the polyolefin resin include polypropylene, polyethylene, polymethylpentene, an ethylene-vinyl alcohol copolymer, and an olefin-based copolymer. From the viewpoint of heat resistance, the polyolefin-based resin is preferably polypropylene, polymethylpentene, an ethylene-vinyl alcohol copolymer, or an olefin-based copolymer.

The polyamide-series resin may be an aliphatic polyamide such as nylon, poly-p-phenylene terephthalamide, poly-p-phenylene terephthalamide-3,4-diphenyl ether terephthalamide, Amide and the like, and semiaromatic polyamides having an aliphatic chain in a part of the main chain in the aromatic polyamide. The wholly aromatic polyamide may be either para type or meta type.

The synthetic resin fibers may be fibers (single fibers) made of a single resin or fibers (composite fibers) made of two or more kinds of resins. Examples of the composite fiber include a sheath-core type, an eccentric type, an eccentric type, a side by side type, a sea type, an orange type, and a multi-bimetal type.

The fibers other than the synthetic resin fibers which can be used in combination with the synthetic resin fibers may be pulp fibers or fibrils of solvent-spun cellulose or regenerated cellulose, short fibers, fibrillated products, natural cellulose fibers, natural cellulose fibers, Inorganic fibers, and the like.

The thickness of the nonwoven fabric made of plastic is preferably 5 to 25 占 퐉, more preferably 5 to 15 占 퐉, from the viewpoint of obtaining a separator having a small thickness and a low internal resistance.

The method of applying the slurry for a lithium ion battery to a substrate is not particularly limited, but various coating methods such as blades, rods, reverse rolls, ribs, dies, curtains, air knives, flexographic, Gravure, and inkjet; a transfer method such as roll transfer and film transfer; and a method of scraping off the coating liquid on the uncoated side after an impression (descent) method such as dipping.

A slurry layer for a lithium ion battery can be formed by performing a crosslinking reaction between a slurry for a lithium ion battery containing components (A) and (C) in a slurry layer (coating layer) for a lithium ion battery. The crosslinking reaction can proceed, for example, when the slurry for a lithium ion battery is dried. Specific drying methods include drying by wind, such as hot air, hot air, and low-humidity air; Vacuum drying; And a drying method by irradiation of infrared rays, far infrared rays, electron beams, and the like.

The lower limit of the temperature at the time of drying is preferably 40 占 폚 or higher, more preferably 45 占 폚 or higher, particularly preferably 50 占 폚 or higher, from the viewpoint of efficiently removing the solvent and the low molecular weight compound from the composition for a porous film, The upper limit is preferably 90 占 폚 or lower, more preferably 80 占 폚 or lower, from the viewpoint of suppressing the deformation of the substrate due to heat.

The lower limit of the drying time is preferably 5 seconds or more, more preferably 10 seconds or more, particularly preferably 15 seconds or more, and the upper limit is preferably 3 minutes or less, more preferably 2 minutes or less. By setting the drying time to a lower limit than the lower limit of the above range, the solvent can be sufficiently removed from the composition for a porous film, so that the output characteristics of the battery can be improved. Also, the production efficiency can be increased by setting the amount to be not more than the upper limit value.

The method for producing the separator for a lithium ion battery may include any step other than the above. The method for producing a separator for a lithium ion battery may include a step of pressurizing a layer (coating layer) of a slurry for a lithium ion battery by a press such as a mold press and a roll press. The binding treatment of the base material with the layer of the slurry for a lithium ion battery can be improved by performing the pressure treatment. However, from the viewpoint of maintaining the porosity of the layer of the slurry for a lithium ion battery within a preferable range, it is preferable to appropriately control the pressure and the pressing time so as not to excessively increase. Further, in order to remove residual water, the method for producing the separator for a lithium ion battery may include a step of vacuum drying or drying in a dryer or the like.

6. Separator / electrode laminate for lithium ion battery

The present disclosure provides a separator / electrode laminate for a lithium ion battery obtained by applying the lithium ion battery slurry to an electrode and drying the electrode.

Hereinafter, the shrinkage resistance, the resistance to breakage and the adhesion to the substrate (hereinafter, referred to as &quot; shrinkage resistance &quot;) of the lithium ion battery when the slurry for a lithium ion battery containing the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A), the ceramic fine particles , The rate characteristic and the output characteristic improvement mechanism are described, but the present invention is not intended to be limited thereto as an explanation.

mechanism

When the slurry is applied and dried, water is volatilized, and the chemical equilibrium between the silanol group and the siloxane bond shifts greatly to the siloxane bond generation side. At this time, a strong hydrogen bonding interaction occurs between the silanol groups present in the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) and the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide A) three-dimensional cross-linking between chains to form a polyacrylamide-polysiloxane complex. That is, it is present stably in the slurry for a lithium ion battery, forms a siloxane bond when the slurry is coated and heated and dried, and plays a role of crosslinking the component (A). Such a crosslinked structure leads to an effect of improving heat shrinkage resistance, endurance, substrate adhesion, rate characteristics, and output characteristics. Therefore, it is considered that the absence of the ceramic fine particles in the lithium ion battery can be suppressed and the heat resistance of the binder itself can be improved by the crosslinking reaction of the component (A).

At the same time, the silanol group of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) acts on the surface of the ceramic fine particles or on the surface of the surface-treated microporous polyolefin resin base material and / or plastic nonwoven fabric, Lt; / RTI &gt; As a result, it is believed that the adhesion can be improved by improving the adhesion of the ceramic fine particles.

A method for producing a separator / electrode laminate for a lithium ion battery includes the steps of applying, drying and pressing a slurry containing an electrode material such as a slurry for a lithium ion battery to a current collector, a step of forming a slurry on the dried material of the slurry containing the electrode material A method of coating the slurry for the lithium ion battery and drying the slurry for the electrode active material rather than the electrode active material). The coating method, the drying method, the conditions, and the like are exemplified above.

[7. Lithium ion battery]

The present disclosure provides a lithium ion battery including the electrode for the lithium ion battery. The present disclosure also provides a lithium ion battery comprising the separator for a lithium ion battery and / or the separator / electrode laminate for the lithium ion battery. The battery also includes an electrolytic solution and a packaging material, and they are not particularly limited.

(Electrolytic solution)

Examples of the electrolytic solution include a nonaqueous electrolytic solution in which a supporting electrolyte is dissolved in a nonaqueous solvent. The non-aqueous liquid electrolyte may contain a film forming agent.

As the nonaqueous solvent, various known solvents may be used without particular limitation, and they may be used alone or in combination of two or more. Examples of the non-aqueous solvent include chain carbonate solvents such as diethyl carbonate, dimethyl carbonate and ethyl methyl carbonate; Cyclic carbonate solvents such as ethylene carbonate, propylene carbonate, and butylene carbonate; Chain ether solvents such as 1,2-dimethoxyethane; Cyclic ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, sulfolane, and 1,3-dioxolane; Chain ester solvents such as methyl formate, methyl acetate and methyl propionate; cyclic ester solvents such as? -butyrolactone and? -valerolactone; Acetonitrile and the like. Among these, a combination of a cyclic carbonate and a mixed solvent containing a chain carbonate is preferable.

As the supporting electrolyte, a lithium salt is used. As the lithium salt, various known ones may be used without particular limitation, and they may be used alone or in combination of two or more. The supporting electrolyte may be selected from the group consisting of LiPF ₆ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAlCl ₄ , LiClO ₄ , CF ₃ SO ₃ Li, C ₄ F ₉ SO ₃ Li, CF ₃ COOLi, (CF ₃ CO) ₂ NLi, ₃ SO ₂ ) ₂ NLi, (C ₂ F ₅ SO ₂ ) NLi, and the like. Of these, LiPF ₆ , LiClO ₄ , and CF ₃ SO ₃ Li are preferred because they exhibit a high degree of dissociation that is easily dissolved in a solvent. The higher the degree of dissociation of the supporting electrolyte, the higher the lithium ion conductivity. Therefore, the lithium ion conductivity can be controlled depending on the type of the supporting electrolyte.

As the film-forming agent, various known agents may be used without particular limitation, and they may be used alone or in combination of two or more kinds. Examples of the film-forming agent include a carbonate compound such as vinylene carbonate, vinylethylene carbonate, vinylethyl carbonate, methylphenyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate and the like; Alkenesulfides such as ethylene sulfide and propylene sulfide; Sultone compounds such as 1,3-propane sultone and 1,4-butane sultone; Maleic anhydride, succinic anhydride and the like. The content of the film-forming agent in the electrolyte solution is not particularly limited, but is preferably 10 mass% or less, 8 mass% or less, 5 mass% or less and 2 mass% or less. When the content is 10 mass% or less, it is easy to suppress the initial irreversible capacity, which is an advantage of the film former, and to improve the low temperature characteristics and the rate characteristics.

The form of the lithium ion battery is not particularly limited. Examples of the shape of the lithium ion battery include a cylinder type having a sheet electrode and a spiral in a separator, a cylinder type having an inside-out structure in which a pellet electrode and a separator are combined, a coin type in which a pellet electrode and a separator are laminated, and the like. In addition, these types of batteries can be used in an arbitrary shape such as a coin shape, a cylindrical shape, or a quadrangle shape by inserting them into an optional external case.

The method of manufacturing the lithium ion battery is not particularly limited, and it may be assembled in an appropriate order according to the structure of the battery. A method of manufacturing a lithium ion battery is exemplified by the method described in Japanese Patent Application Laid-Open No. 2013-089437. A battery can be manufactured by providing a negative electrode on an outer case, providing an electrolyte solution and a separator thereon, and a negative electrode facing the negative electrode with a gasket and a sealing plate.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following embodiments. In the following, &quot; part &quot; and &quot;% &quot; indicate mass parts and mass%, respectively, unless otherwise specified.

< Preparation of component (b) >

Preparation of Component (b-1)

100 g of ion-exchanged water, 100 g of vinyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name &quot; KBM- &quot;, product of Shin-Etsu Chemical Co., Ltd.) was added to a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, 1003 "), 1.23 g of nitric acid and 1.00 g of methanol were placed and reacted at 25 ° C. for 0.5 hour to obtain a homogeneous aqueous solution containing the double bond-containing trihydroxysilyl compound (b-1) .

(b-2)

To the reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser tube and a nitrogen gas inlet tube, 100 g of ion-exchanged water and 0.66 g (0.0028 g) of 3-acryloxypropyltrimethoxysilane (product name: KBM- , 1.23 g of nitric acid and 1.00 g of methanol were placed and the mixture was reacted at 25 DEG C for 0.5 hour to obtain a homogeneous aqueous solution containing the double bond-containing trihydroxysilyl compound (b-2).

(b-3)

To the reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser tube and a nitrogen gas inlet tube were added 100 g of ion-exchanged water and 0.7 g of 3-methacryloxypropyltrimethoxysilane (product name: KBM-503, , 1.23 g of nitric acid and 1.00 g of methanol, and the mixture was reacted at 25 DEG C for 0.5 hour to obtain a homogeneous aqueous solution containing the double bond-containing trihydroxysilyl compound (b-3).

(b-4)

100 g of ion-exchanged water, 100 g of methanol and 200 g of 3-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser tube and a nitrogen gas inlet tube And the mixture was reacted at 25 DEG C for 0.5 hour to obtain a uniform aqueous solution containing the trihydroxysilyl compound (b-4).

&Lt; Preparation of component (A) >

Production Example 1

To a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube were added 1011 g of ion-exchanged water, 400 g (2.81 mol) of 50% acrylamide aqueous solution, sodium methallylsulfonate (2-methyl- -Sulfonic acid sodium) (0.0014 mol) were added. Then, a tri-hydride-containing trihydroxysilyl compound (b-1) was added in the system. The pH at that time was 2.2. After the oxygen in the reaction system was removed through nitrogen gas, the temperature was raised to 50 캜. 2.0 g of 2,2'-azobis-2-amidinopropane dihydrochloride (product name "NC-32", product of NIPPO CHEMICALS CO., LTD.) And 30 g of ion-exchanged water were added thereto, Lt; 0 &gt; C for 3.0 hours. An aqueous solution containing a water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) having a viscosity (25 ° C) of 24,000 mPa · s was obtained.

Production Examples 2 to 13, Comparative Production Examples 1 to 6

An aqueous solution containing the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) was prepared in the same manner as in Preparation Example 1, except that the monomer composition and the reaction concentration were changed as shown in Table 1.

Production Example 14

(B-4) in an amount of 5% by mass based on the solid content in the aqueous solution prepared in Preparation Example 6 to prepare an aqueous solution containing poly (meth) acrylamide (A) containing a water-soluble trihydroxy silyl group &Lt; / RTI &gt;

Production Example 15

In Production Example 6, a 40% aqueous solution of glyoxal (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the prepared aqueous solution so as to be 1% by mass based on the solid content to obtain a water-soluble trihydroxy silyl group-containing poly To obtain an aqueous solution containing (meth) acrylamide (A).

AM: acrylamide (50% acrylamide manufactured by Mitsubishi Chemical Corporation)

ATBS: Acrylamide t-butylsulfonic acid ("ATBS" manufactured by TOAGOSEI CO., LTD.)

NMAM: N-methylol acrylamide (manufactured by Tokyo Chemical Industry Co., Ltd. (TCI))

AA: Acrylic acid (80% acrylic acid, product of Osaka Organic Chemical Industry Ltd.)

AN: acrylonitrile ("acrylonitrile" manufactured by Mitsubishi Chemical Co., Ltd.)

HEMA: 2-hydroxyethyl methacrylate (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

SMAS: sodium methacrylate sulfonate

The physical properties of the component (A) described in the table were measured as follows.

Gel fraction

The aqueous solution of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) was stirred at 120 ° C for 4 hours with a circulating air dryer (manufactured by Advantec Toyo Kaisha, Ltd., trade name "DSR420DA" After drying, a solid resin was obtained. The solid resin was precisely weighed and immersed in water for 3 hours with stirring. The mixture was filtered under reduced pressure through a filter paper (Kiriyama Glass Works Co., product No. 50B, product of KIRIYAMA RHOTO). Thereafter, the filtrate was dried at 120 ° C for 3 hours, and the mass of the insoluble residue was accurately measured. From the following equation, it was found that the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) The gel fraction was calculated.

(%) Of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) = {insoluble residue (g) / mass of solid resin

B type viscosity

The viscosity of each binder aqueous solution was measured at 25 DEG C under the following conditions using a B-type viscometer (product name: &quot; B-type viscometer model BM &quot;

When the viscosity is 100,000 to 20,000 mPa · s: No. 4 rotor is used, the number of revolutions is 6 rpm, the viscosity is less than 20,000 mPa · s: No. 3 rotor is used, the number of revolutions is 6 rpm.

Weight average molecular weight

The weight average molecular weight was determined by gel permeation chromatography (GPC) in terms of polyacrylic acid measured in 0.2 M phosphate buffer / acetonitrile solution (90/10, pH 8.0). The GPC apparatus used was HLC-8220 (manufactured by Tosoh Corporation) and the column was SB-806M-HQ (manufactured by SHODEX Corporation).

Example 1-1 Evaluation of Electrode

(1) Preparation of Slurry for Lithium Ion Battery

The water-soluble trihydroxysilyl group-containing poly (meta) of Production Example 1 was added to a container dedicated to the mixer using a commercially available revolving-air mixer (product name: "Awatore Rentero", manufactured by THINKY CORPORATION) ) 7 parts of an aqueous solution of acrylamide (A) in terms of solid content, 46.5 parts of silicon particles having a D50 of 5 탆, natural graphite (product name: Z-5F, manufactured by Ito Graphite Co., ) Were mixed. The ion exchange water was added thereto so as to have a solid content concentration of 40%, and the vessel was set in the mixer. Subsequently, the mixture was kneaded at 2000 rpm for 10 minutes and defoamed for 1 minute to obtain a slurry for a lithium ion battery.

(2) Manufacture of electrode for lithium ion battery

The slurry for a lithium ion battery was uniformly coated on the surface of a current collector made of a copper foil by a doctor blade method so that the film thickness after drying was 25 占 퐉 and dried at 60 占 폚 for 30 minutes and then dried at 150 占 폚 / Heat treatment for 120 minutes under vacuum to obtain an electrode. Thereafter, the electrode was pressed by means of a roll press machine so that the membrane (electrode active material layer) had a density of 1.5 g / cm &lt; ³ &gt;.

(3) Preparation of lithium half cell

A twin-screw type coin cell (manufactured by Hohsen Corp., trade name "HS Flat Cell", manufactured by Takara Shuzo Co., Ltd.) was produced by piercing the electrode with a diameter of 16 mm in an argon-substituted glove box ). Then, a separator (made by CS TECH CO., LTD., Product name: "Selion P2010") made of a polypropylene porous membrane having a hole having a diameter of 24 mm was placed and 500 μL of the electrolytic solution was injected so as to prevent air from entering. A metal lithium foil was punched out with a hole of 16 mm, and the external body of the bipolar coin cell was sealed with a screw to assemble the lithium half cell. The electrolytic solution used herein was a solution of LiPF ₆ dissolved in a solvent of ethylene carbonate / ethyl methyl carbonate = 1/1 (mass ratio) at a concentration of 1 mol / L.

Examples 1-2 to 1-10 and Comparative Examples 1-1 to 1-3

A lithium half cell was obtained in the same manner except that the composition was changed as shown in the following table. The slurry for the lithium ion battery of Example 1-10 was prepared in the following order.

Preparation of Slurry for Lithium Ion Battery of Example 1-10

An aqueous solution of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide shown in Table 1 was prepared. Next, a mixed solution of 25 g of ion-exchanged water and 25 g of methanol was prepared in a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser tube and a nitrogen gas inlet tube, and 3-aminopropyltrimethoxysilane (product of Shin-Etsu Chemical Co., KBM-903 &quot;) was added, and the mixture was reacted at 25 DEG C for 0.5 hour to obtain a uniform aqueous solution containing 3-aminopropyltrihydroxysilane. Aqueous solution of 3-aminopropyltrihydroxysilane was added so as to be 2% by mass based on the solid content of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide aqueous solution. A slurry for a lithium ion battery was obtained in the same manner as in Example 1-1 except for the above.

Acetylene black (trade name: DENKA BLACK, manufactured by Denka Company Limited)

The slurry dispersibility, spring back rate and discharge capacity retention ratio in the table were measured by the following methods.

&Lt; Evaluation of slurry dispersibility &

The dispersibility immediately after the preparation of the slurry was visually evaluated based on the following criteria.

?: The whole was in a homogeneous paste state, no liquid phase separation and no aggregates were observed.

?: The whole was a substantially homogeneous paste-like state, and although slight liquid separation was confirmed, aggregates were not confirmed.

DELTA: A small amount of aggregate and a slight amount of liquid phase separation were observed at the bottom of the container.

X: A large number of clay-like aggregates were found on the bottom of the container, and a large amount of liquid phase separation was confirmed.

&Lt; Evaluation of electrical characteristics: spring rate and discharge capacity retention rate >

(1) Charge / discharge measurement

The lithium half cell prepared above was placed in a constant temperature bath at 25 캜, and charging was started at a constant current (0.1 C). When the voltage reached 0.01 V, charging was completed (cut off). Subsequently, discharging was started at a constant current (0.1 C), and charging and discharging for making discharge completion (cutoff) at the time when the voltage became 1.0 V were repeated 30 times.

(2) the springback rate of the electrode due to repetition of charging and discharging

After 30 cycles of charging / discharging cycle test at room temperature (25 캜), the lithium half cell was disassembled and the thickness of the electrode was measured. The spring rate of the electrode was obtained by the following formula.

(Electrode thickness after 30 cycles-current collector thickness) / (electrode thickness before charge / discharge-current collector thickness)} 100 - 100 (%)

(3) Discharge capacity maintenance rate

The discharge capacity retention rate was obtained from the following equation.

Discharge capacity retention rate = {(discharge capacity at 30th cycle) / (discharge capacity at 1st cycle)} 100 (%)

In the above measurement conditions, &quot; 1C &quot; indicates a current value at which the discharge is completed within one hour by constant current discharge of a cell having a certain constant capacitance. For example, &quot; 0.1C &quot; refers to a current value at which discharge is completed over 10 hours, and &quot; 10C &quot; refers to a current value at which discharge is completed over 0.1 hour.

As clearly shown in Table 2, all of the slurries of Examples 1-1 to 1-10 had good evaluation of slurry dispersibility. Evaluation of the springback rate and the discharge capacity retention ratio were all good in the evaluation of the lithium half cell produced from the slurry of Examples 1-1 to 1-10.

On the other hand, the slurry for electrodes (Comparative Example 1-1) containing no trihydroxy silyl group having double bonds and the slurry for electrodes having a large amount of trihydrosiloxy compound (b) having double bonds (Comparative Example In the case of the electrode slurry (Comparative Example 1-3) having a small amount of the (meth) acrylamide (a) component, the dispersibility of the electrode slurry, the spring half rate of the lithium half cell manufactured using the same, The capacity retention rate was falling.

Example 1A: Preparation of laminate-type lithium ion battery

Using the slurry for the lithium ion battery of Example 1-1, a laminate type lithium ion battery was produced as follows.

(1) Production of negative electrode

A slurry for a lithium ion battery prepared in Example 1-1 was placed on a current collector made of a copper foil and coated in the form of a film using a doctor blade. The slurry for the lithium ion battery was coated on the current collector, dried at 80 DEG C for 20 minutes, volatilized to remove water, and adhered and bonded by a roll press machine. At this time, the density of the electrode active material layer was set to 1.0 g / cm ² . The laminate was heated at 120 DEG C for 2 hours in a vacuum drier and cut into a predetermined shape (rectangular shape of 26 mm x 31 mm) to obtain a negative electrode having an electrode active material layer thickness of 15 mu m.

(2) Production of positive electrode

88 parts by mass, 6 parts by mass and 6 parts by mass of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as a positive electrode active material, acetylene black as a conductive auxiliary agent and polyvinylidene fluoride (PVDF) as a binder were mixed, Of N-methyl-2-pyrrolidone (NMP) to prepare a lithium ion battery positive electrode slurry. Subsequently, an aluminum foil was prepared as a current collector of a positive electrode, and a lithium ion battery positive electrode slurry was placed on an aluminum foil and coated with a doctor blade so as to have a film shape. The aluminum foil after application of the slurry for the lithium ion battery positive electrode was dried at 80 DEG C for 20 minutes to remove the NMP by volatilization and then adhered and bonded by a roll press machine. At this time, the density of the positive electrode active material layer was set to 3.2 g / cm ² . The laminate was heated at 120 DEG C for 6 hours in a vacuum dryer and cut into a predetermined shape (rectangular shape of 25 mm x 30 mm) to obtain a positive electrode having a thickness of about 45 mu m as the positive electrode active material layer.

(3) Production of laminate type lithium ion battery

Using the above positive electrode and negative electrode, a laminate type lithium ion secondary battery was produced. Specifically, a rectangular sheet (27 x 32 mm, thickness: 25 m) of a separator (made by CS TECH CO., LTD., Product name &quot; Selion P2010 &quot;) made of a polypropylene porous membrane was sandwiched between the positive electrode and the negative electrode, (Plate group). This electrode plate group was covered with two pairs of sheets of a laminate film, three sides were sealed, and an electrolytic solution was injected into the bag-shaped laminate film. A solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / L in a solvent of ethylene carbonate / ethyl methyl carbonate = 1/1 (by mass ratio) was used as an electrolyte solution. Thereafter, the other side was sealed so that the four sides were hermetically sealed to obtain a laminate-type lithium ion secondary battery in which the electrode plate group and the electrolyte were sealed. The positive electrode and the negative electrode are provided with tabs electrically connectable to the outside, and a part of the tab extends outside the laminate type lithium ion secondary battery. When the laminate type lithium ion battery produced by the above process was energized, there was no operational problem.

Example 2-1: Evaluation of separator

(1) Preparation of slurry

5 parts by mass in terms of solid content and 113 parts by mass of water-soluble polymer (nonvolatile matter 13%, 25 ° C, viscosity 24,000 mPa · s) synthesized in Production Example 1 were stirred and mixed, and 100 parts by mass of boehmite And the mixture was dispersed and stirred in a homogenizer (T25 digital ULTRA-TURRAX manufactured by IKA) at 15,000 rpm for 60 minutes. Ion-exchanged water was added to adjust the viscosity to prepare a slurry.

(2) Production of separator: A laminate of a layer (coating layer) of a slurry for a separator

(PE substrate) made of a single layer polyethylene made by a wet method (width method) having a width of 250 mm, a length of 200 mm and a thickness of 6 탆 was prepared. The slurry solution obtained above was coated on one side of the separator using a gravure coater so as to have a thickness of 3.0 mu m after drying and dried to obtain a lithium ion battery separator.

Examples 2-2 to 2-15 and Comparative Examples 2-1 to 2-6

A separator for a lithium ion battery was obtained in the same manner as in Example 2-1 except that the composition was changed as shown in the following table.

Examples 2-16

A separator / electrode laminate for a lithium ion battery was obtained in the same manner as in Example 2-2 except that the slurry liquid was coated on the positive electrode side.

Examples 2-17

A separator for a lithium ion battery was obtained in the same manner as in Example 2-2 except that the slurry liquid was coated on a polyethylene terephthalate nonwoven fabric substrate (PET substrate) having a width of 200 mm, a length of 200 mm, a thickness of 9 m, and a weight per unit area of 11 g / m ² .

The heat shrinkability, endurance, adhesion, rate resistance and output characteristics in the table were measured by the following methods.

<Heat shrinkage resistance>

The separator and separator / electrode laminate obtained in Examples and Comparative Examples were cut into squares having a width of 12 cm and a length of 12 cm, and squares each having a side of 10 cm were drawn inside the square to obtain test pieces. The test piece was placed in a thermostatic chamber at 150 캜 and allowed to stand for 1 hour to heat treatment. After the heat treatment, the area of the green square inside was measured, and the change in the area before and after the heat treatment was determined as the heat shrinkage percentage, and the heat resistance was evaluated according to the following criteria. The smaller the heat shrinkage ratio, the better the heat shrinkability of the separator.

○: area shrinkage rate is less than 1%

△: area shrinkage ratio is 1% or more and less than 3%

X: area shrinkage of not less than 3%

<Endocrine Disruption>

The separator and separator / electrode laminate obtained in Examples and Comparative Examples were cut out into squares of 10 cm x 10 cm and weighed precisely the mass (X0). One side was fixed on a thick paper and fixed. Then, (Minute copper) were placed on the ceramic layer side, and these were rubbed with each other at a rotation speed of 50 rpm for 10 minutes. Thereafter, the mass X1 is accurately measured again, and the following equation

Granularity = {(X0-X1) / X0} x100

(Mass%) was calculated in accordance with the following criteria to evaluate the endocrystallization of the separator according to the following criteria.

A: The blendability is less than 2% by mass

B: 2% by mass or more and less than 5% by mass

C: 5% or more by mass

<Adhesion of Separator (Peel strength)>

Test pieces having a width of 2 cm and a length of 10 cm were cut out from the separator and the separator / electrode laminate obtained in Examples and Comparative Examples, and the coated surface was fixed with the upper surface facing up. Subsequently, an adhesive tape ("CELLOTAPE (registered trademark)" manufactured by Nichiban Co., Ltd.) having a width of 15 mm (specified in JIS Z1522) was placed on the surface of the ceramic layer of the test piece The adhesive tape was peeled off from one end of the test piece using a tensile tester ("TENSILON RTM-100", product of A & D Company, Limited) at 25 ° C And the stress was measured at a rate of 30 mm / minute in the direction of 180 DEG. The measurement was carried out five times, converted into a value per 15 mm width, and the average value was calculated as the peel strength. The larger the peel strength is, the higher the adhesion strength between the substrate and the ceramic layer or the bondability between the ceramic layers is, and it is difficult for the ceramic layers or the ceramic layers to peel off from the separator base.

&Lt; Rate Resistance, Output Characteristics >

(1) Production of laminate type lithium ion battery

In measuring the rate resistance and output characteristics, a laminate type lithium ion battery was produced as follows.

(1-1) Production of negative electrode

(SBR) / carboxymethylcellulose (CMC) (mass ratio of 1: 1) was added to a container dedicated to the mixer using a commercial revolving mixer (product name: "Awatore Rentero" 2) and 98 parts of natural graphite (trade name &quot; Z-5F &quot;, product of Ito Graphite Industry Co., Ltd.) were mixed. The ion exchange water was added thereto so as to have a solid content concentration of 40%, and the vessel was set in the mixer. Subsequently, the mixture was kneaded at 2000 rpm for 10 minutes and defoamed for 1 minute to obtain a slurry for a lithium ion battery. A slurry for a lithium ion battery was placed on a current collector made of a copper foil and coated in a film form using a doctor blade. The slurry for the lithium ion battery was coated on the current collector, dried at 80 DEG C for 20 minutes, volatilized to remove water, and adhered and bonded by a roll press machine. At this time, the density of the electrode active material layer was set to 1.0 g / cm ² . The laminate was heated at 120 DEG C for 2 hours in a vacuum drier and cut into a predetermined shape (rectangular shape of 26 mm x 31 mm) to obtain a negative electrode having an electrode active material layer thickness of 15 mu m.

(1-2) Production of laminate type lithium ion battery

A laminate-type lithium ion secondary battery was produced using the negative electrode and the positive electrode prepared in Example 1A. Specifically, a rectangular sheet (27 占 32 mm, thickness: 25 占 퐉) was sandwiched between the positive electrode and the negative electrode to obtain a separator obtained in Examples and Comparative Examples. The electrode plate group was covered with a pair of laminate films, and the three sides were sealed, and then an electrolytic solution was injected into the bag-shaped laminate film. A solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / L in a solvent of ethylene carbonate / ethyl methyl carbonate = 1/1 (by mass ratio) was used as an electrolyte solution. Thereafter, the other side was sealed so that the four sides were hermetically sealed to obtain a laminate-type lithium ion secondary battery in which the electrode plate group and the electrolyte solution were sealed. The positive electrode and the negative electrode are provided with tabs electrically connectable to the outside, and a part of the tab extends outside the laminate type lithium ion secondary battery. When the laminate type lithium ion battery produced by the above process was energized, there was no operational problem.

(2) Measurement of rate resistance and output characteristics

The prepared lithium ion secondary battery was charged at a rate of 2.5 to 4.2 V at 25 DEG C at 0.1 DEG C. When the voltage reached 4.2 V, charging was continuously continued at a constant voltage (4.2 V) The point at which C became full was the charge completion (cutoff). Subsequently, charge and discharge for discharging up to 2.5 V at 0.1 C were repeated five times. After 6th cycle, discharging was changed to 1 C, and charging and discharging were repeated for 50 cycles. The value obtained by calculating the ratio of the 1C discharge capacity at the 6th cycle in the charge capacity at the 6th cycle as a percentage was defined as the initial rate maintenance rate. The larger this value is, the better the rate resistance is. The value obtained by calculating the ratio of the 1C discharge capacity at the 50th cycle to the 1C discharge capacity at the 5th cycle as a percentage was defined as the capacity retention rate. The larger this value is, the better the output characteristic is.

Claims (16)

With respect to 100 mol% of the monomer group,
(Meth) acrylamide group-containing compound (a) in an amount of 60 mol% or more,
Containing trihydroxy silyl compound (b) having a vinyl group or a (meth) acryloxy group in an amount of 0.05 to 0.80 mol%
The polymer of the group of monomers involved
A binder aqueous solution for a lithium ion battery comprising a water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A).
With respect to 100 mol% of the monomer group,
(Meth) acrylamide group-containing compound (a) in an amount of 60 mol% or more,
Containing trihydroxy silyl compound (b) having a vinyl group or a (meth) acryloxy group in an amount of 0.05 to 0.80 mol%
The polymer of the group of monomers involved
A slurry for a lithium ion battery comprising a water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A).
The method according to claim 2, wherein
A slurry for a lithium ion battery comprising a trihydroxy silyl compound or a tetrahydroxy silyl compound.
The method according to claim 2 or 3,
Wherein the gel fraction (gel fraction) of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) is 50% or more.
The method according to any one of claims 2 to 4,
A slurry for a lithium ion battery comprising an electrode active material (B).
6. The method of claim 5,
A slurry for a lithium ion battery comprising 1 to 15 mass% of the water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A) based on 100 mass% of the electrode active material (B).
The method according to claim 5 or 6,
Wherein the electrode active material (B) comprises 20% by mass or more of silicon or silicon oxide covered with a carbon layer.
The method according to any one of claims 2 to 4,
A slurry for a lithium ion battery comprising the ceramic fine particles (C).
9. The method of claim 8,
A slurry for a lithium ion battery comprising 1 to 15 mass% of the water-soluble trihydroxysilyl group-containing poly (meth) acrylamide (A) based on 100 mass% of the ceramic fine particles (C).
With respect to 100 mol% of the monomer group,
(Meth) acrylamide group-containing compound (a) in an amount of 60 mol% or more,
Containing trihydroxy silyl compound (b) having a vinyl group or a (meth) acryloxy group in an amount of 0.05 to 0.80 mol%
The polymer of the group of monomers involved
The method for producing a slurry for a lithium ion battery according to any one of claims 2 to 9, comprising a step of mixing water with a water-soluble trihydroxy silyl group-containing poly (meth) acrylamide (A).
An electrode for a lithium ion battery obtained by applying a slurry for a lithium ion battery according to any one of claims 2 to 7 to a collector and drying the slurry.
12. The method of claim 11,
Wherein the current collector is a copper foil.
A lithium ion battery comprising the electrode for the lithium ion battery according to claim 11 or 12.
A separator for a lithium ion battery obtained by applying a slurry for a lithium ion battery according to any one of claims 2 to 4, 8 and 9 to a porous (polyolefin) resin base or a plastic nonwoven fabric and drying the slurry.
A separator / electrode laminate for a lithium ion battery, which is obtained by applying a slurry for a lithium ion battery according to any one of claims 2 to 4, 8 and 9 to an electrode and drying it.
A lithium ion battery comprising the separator for a lithium ion battery according to claim 14 and / or the separator / electrode laminate for a lithium ion battery according to claim 15.