KR20190082977A - A binder composition for a nonaqueous electrolyte battery electrode, a hydrogel using the same, and a slurry composition for a nonaqueous electrolyte battery electrode using the same, a nonaqueous electrolyte battery negative electrode, and a nonaqueous electrolyte battery - Google Patents

Abstract

The present invention relates to a binder composition for a nonaqueous electrolyte battery electrode containing a neutralized salt of an? -Olefin-maleic acid copolymer in which? -Olefins and maleic acid are copolymerized and a crosslinking agent, a slurry composition for a nonaqueous electrolyte battery electrode using the binder composition, An electrolyte battery negative electrode, and a nonaqueous electrolyte battery.

Description

A binder composition for a nonaqueous electrolyte battery electrode, a hydrogel using the same, and a slurry composition for a nonaqueous electrolyte battery electrode using the same, a nonaqueous electrolyte battery negative electrode, and a nonaqueous electrolyte battery

The present invention relates to a binder composition for a nonaqueous electrolyte battery electrode, a hydrogel using the same as a raw material, a slurry composition for a nonaqueous electrolyte battery electrode using the same, a nonaqueous electrolyte battery negative electrode, and a nonaqueous electrolyte battery.

2. Description of the Related Art In recent years, the spread of mobile terminals such as portable telephones, notebook personal computers, and padded information terminal devices has been remarkable. Lithium ion secondary batteries are widely used in secondary batteries used for power supply of these portable terminals. Since portable terminals are required to have more comfortable portability, miniaturization, thinning, light weight, and high performance have been rapidly progressed and they have been used in various places. This trend is still continuing, and battery cells used in portable terminals are required to be smaller in size, thinner, lighter, and have higher performance.

A non-aqueous electrolyte cell such as a lithium ion secondary battery includes a positive electrode and a negative electrode provided with a separator interposed therebetween, and is made of LiPF ₆ , LiBF ₄ LiTFSI (lithium (bistrifluoromethylsulfonylimide)), LiFSI (lithium (bis Sulfonyl imide)) in an organic liquid such as ethylene carbonate or the like, together with an electrolytic solution.

The negative electrode and the positive electrode are usually prepared by dissolving or dispersing a binder and a thickening agent in water and adding an active material and a conductive auxiliary agent (a conductive agent) Is applied to the current collector, and the water is dried to bind as a mixed layer. More specifically, for example, the negative electrode can be made of a carbonaceous material capable of intercalating and deintercalating lithium ions, which is an active material, and, if necessary, acetylene black or the like of a conductive auxiliary, by a binder for a secondary battery electrode It is mutual adhesion. On the other hand, the positive electrode is obtained by binding LiCoO ₂ as an active material and, if necessary, a conductive auxiliary agent similar to that of the negative electrode to a collector such as aluminum using a binder for a secondary battery electrode.

Heretofore, dienic rubbers such as styrene-butadiene rubber and acrylic rubbers such as polyacrylic acid have been used as binders for water (see, for example, Patent Documents 1 and 2). Examples of the thickening agent include methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropoxycellulose, carboxymethylcellulose sodium salt (CMC-Na), and sodium polyacrylate. Of these, CMC-Na is frequently used (For example, Patent Document 3).

However, the diene-based rubber such as styrene-butadiene rubber has a low adhesiveness to a metal collecting electrode such as copper and has a problem that the amount of use can not be lowered in order to improve the adhesion between the collecting electrode and the electrode material. In addition, there is a problem in that it is weak against heat generated during charging / discharging, and the capacity retention rate is low. On the other hand, sodium polyacrylate exhibits higher adhesiveness than the styrene-butadiene rubber type, but has a problem that the electrode is easily broken because the electrical resistance is high and the electrode is hardened and the toughness is insufficient. In recent years, there has been an increasing demand for extending the operating time of portable terminals and shortening the charging time, and there is a pressing need to improve the capacity (low resistance), life (cycle characteristics) and charging speed , Which are particularly troublesome.

In the non-aqueous electrolyte cell, since the battery capacity is influenced by the amount of the active material, it is effective to suppress the amount of the binder and the thickener in order to increase the active material within a limited space of the battery. Also, with respect to the rate characteristic, it is effective to suppress the amount of the binder and the thickener which obstruct the movement of electrons in a non-conductive manner because it is influenced by the ease of electron transfer. However, if the amount of the binder and the thickening agent is decreased, the binding property between the collector electrode and the electrode material and the active material in the electrode deteriorates, durability (battery life) for long-term use is remarkably lowered, Throw away. In this way, until now, it has been difficult to improve the battery characteristics such as the battery capacity while holding the tackiness between the collector electrode and the electrode material and holding the toughness as the electrode.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to improve battery characteristics in a non-aqueous electrolyte battery without deteriorating the function as a binder, that is, toughness as an electrode.

Another object of the present invention is to improve the battery characteristics in the non-aqueous electrolyte battery without deteriorating the bondability between the active material and the collector electrode.

Japanese Unexamined Patent Application Publication No. 2000-67917 Japanese Patent Application Laid-Open No. 2008-288214 Japanese Unexamined Patent Application Publication No. 2014-13693

DISCLOSURE OF THE INVENTION As a result of intensive studies for solving the above problems, the present inventors have found that the above objects can be achieved by using a binder composition for a nonaqueous electrolyte battery electrode having the following constitution, .

That is, the binder composition for a nonaqueous electrolyte battery electrode according to one aspect of the present invention (hereinafter, simply referred to as a binder composition) is prepared by dissolving a neutralized salt of an? -Olefin-maleic acid copolymer in which? -Olefins and maleic acid are copolymerized, A binder composition for a non-aqueous electrolyte cell electrode comprising a structure crosslinked by amines, wherein the aqueous solution containing 10 wt% of the binder composition has a viscosity at 25 ° C and a shear rate of ^{40 s -1} of 1800 mPa · s to 15000 mPa · s s.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto.

The binder composition for a nonaqueous electrolyte battery electrode of the present embodiment is a binder composition for a nonaqueous electrolyte battery electrode containing a structure in which a neutralized salt of an alpha -olefin-maleic acid copolymer in which alpha -olefins and maleic acid are copolymerized is crosslinked with polyamines The binder composition is characterized in that the aqueous solution containing 10 wt% of the binder composition has a viscosity at 25 ° C and a shear rate of ^{40 s -1} of 1800 mPa · s to 15000 mPa · s.

According to such a constitution, a binder composition for a non-aqueous electrolyte cell electrode having binding properties and toughness can be obtained, and the battery characteristics of the nonaqueous electrolyte battery can be improved by using the same.

In the present embodiment, the? -Olefin-maleic acid copolymer in which the? -Olefins and the maleic acid are copolymerized is composed of the? -Olefin-based unit (A) and the maleic acid-based unit (B). Each of the components (A) and (B) preferably satisfies (A) / (B) (molar ratio) from 1/1 to 1/3. It is also preferable to be a linear random copolymer having an average molecular weight of 10,000 to 500,000.

In the present embodiment, the unit (A) based on? -Olefins means a group represented by the general formula -CH ₂ CR ¹ R ² - (wherein R ¹ and R ² may be the same or different and each is hydrogen, Lt; 10 > represents an alkyl group or an alkenyl group). The? -Olefin used in the present embodiment is a straight chain or branched olefin having a carbon-carbon unsaturated double bond at the? -Position. In particular, olefins having from 2 to 12, in particular from 2 to 8, carbon atoms are preferred. Representative examples which can be used are ethylene, propylene, n-butylene, isobutylene, n-pentene, isoprene, 2-methyl-1-butene, 2-ethyl-1-butene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethylbutadiene, 2, Pentadiene, 1,4-hexadiene, 2,2,4-trimethyl-1-pentene, styrene,? -Methylstyrene, paramethylstyrene, methylvinylether and ethylvinylether. Of these, isobutylene is particularly preferable from the viewpoints of availability, polymerizability, and stability of the product. Herein, isobutylene includes a mixture containing isobutylene as a main component, for example, a BB fraction (C4 fraction). These olefins may be used alone or in combination of two or more.

In the present embodiment, examples of the unit (B) based on maleic acid include maleic anhydride, maleic acid, maleic acid monoester (for example, methyl maleate, ethyl maleate, propyl maleate, , Maleic anhydride derivatives such as maleic acid diesters (e.g., dimethyl maleate, diethyl maleate, dipropyl maleate, dipropyl maleate, etc.), maleic acid imides or N-substituted derivatives thereof N-substituted maleimide such as maleic acid imide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, Nn-butylmaleimide, Nt-butylmaleimide and N-cyclohexylmaleimide N-substituted alkylphenyl maleimides such as N-phenylmaleimide, N-methylphenylmaleimide and N-ethylphenylmaleimide, N-substituted phenylmaleimides such as N-methoxyphenylmaleimide and N-ethoxyphenylmaleimide, Alkoxyphenylmaleimide), and halides thereof (for example, N-Cl (Such as phenylmaleimide), anhydrous citraconic acid, citraconic acid, citraconic acid monoester (e.g., methyl citraconate, ethyl citraconate, citraconic acid propyl, and citraconic acid phenyl) Anhydrous citraconic acid derivatives such as diesters (e.g., dimethyl citraconate, diethyl citraconate, dipropyl citraconate, diphenyl citraconate and the like), citraconic acid imide or N-substituted derivatives thereof (Such as citraconic acid imide, 2-methyl-N-methylmaleimide, 2-methyl-N-ethylmaleimide, 2-methyl-N-propylmaleimide, 2-methyl-N-phenylmaleimide such as 2-methyl-N-butylmaleimide and 2-methyl-N-cyclohexylmaleimide, 2-methyl-N-methylphenylmaleimide, 2 2-methyl-N-substituted alkylphenylmaleimides such as methyl-N-ethylphenylmaleimide, or 2-methyl-N-methoxyphenylmaleimide, 2- Methyl-N-substituted alkoxyphenylmaleimides such as methyl-N-ethoxyphenylmaleimide), and halides thereof (for example, 2-methyl-N-chlorophenylmaleimide) have. Among them, the use of maleic anhydride is preferable from the viewpoint of availability, polymerization rate, and ease of molecular weight adjustment. These maleic acids may be used alone or in combination of two or more thereof. As described above, the maleic acid is neutralized by an alkali salt, and the resulting carboxylic acid and carboxylate form a 1,2-dicarboxylic acid or salt form. This form has a function of replenishing a heavy metal eluted from the positive electrode.

The content ratio of the respective structural units in the copolymer of the present embodiment is preferably in the range of 1/1 to 1/3 in terms of the molar ratio of (A) / (B). This is because the advantage of hydrophilicity, water solubility, affinity to metals and ions as a high molecular weight compound dissolved in water can be obtained. In particular, it is preferable that the molar ratio of (A) / (B) is 1/1 or a value close thereto, and in this case, a unit based on? -Olefin, that is, a unit represented by -CH ₂ CR ¹ R ² - , And units based on maleic acid are alternately repeated.

The introduction ratio of the? -Olefins and the maleic acid for obtaining the copolymer of the present embodiment varies depending on the composition of the objective copolymer, but the use of an? -Olefin having 1 to 3 times the number of moles of the maleic acid It is effective to increase the reaction rate of the acid.

The method for producing the copolymer of the present embodiment is not particularly limited, and for example, a copolymer can be obtained by radical polymerization. As the polymerization catalyst to be used at this time, an organic peroxide catalyst such as azo catalysts such as azobisisobutyronitrile and 1,1-azobiscyclohexane-1-carbonitrile, benzoyl peroxide, and dicumyl peroxide is preferable. The amount of the polymerization catalyst to be used is in the range of 0.1 to 5 mol% with respect to the maleic acid, but is preferably 0.5 to 3 mol%. As a method of adding a polymerization catalyst and a monomer, they may be collectively added at the beginning of the polymerization, but a method of sequentially adding them in accordance with the progress of the polymerization is preferred.

In the method for producing a copolymer of the present embodiment, the molecular weight can be appropriately controlled depending on the monomer concentration, the amount of the catalyst used, and the polymerization temperature. For example, a salt of a metal of Group I, II or III of the Periodic Table, a hydroxide, a halide of a metal of Group IV, a compound of the general formula N≡, HN═, H ₂ N- or H ₄ N It is also possible to control the molecular weight of the copolymer by adding amines, ammonium compounds such as ammonium acetate, urea or the like, or mercaptans in the initial stage of the polymerization or in the course of the polymerization. The polymerization temperature is preferably 40 占 폚 to 150 占 폚, and more preferably 60 占 폚 to 120 占 폚. If the polymerization temperature is too high, the resulting copolymer tends to become a block-like shape, and the polymerization pressure may remarkably increase. The polymerization time is usually about 1 to 24 hours, more preferably about 2 to 10 hours. The amount of the polymerization solvent to be used is preferably adjusted so that the concentration of the obtained copolymer is 5 to 40% by weight, more preferably 10 to 30% by weight.

As described above, the copolymer of the present embodiment preferably has an average molecular weight of usually 10,000 to 500,000. A more preferred average molecular weight is from 15,000 to 450,000. When the average molecular weight of the copolymer of the present embodiment is less than 10,000, the crystallinity is high and the bonding strength between particles may be small. On the other hand, if it exceeds 500,000, solubility in water or a solvent becomes small, and precipitation may occur easily.

The average molecular weight of the copolymer of the present embodiment can be measured by, for example, a light scattering method or a viscosity method. When the intrinsic viscosity ([eta]) in dimethylformamide is measured using the viscosity method, the copolymer of this embodiment preferably has an intrinsic viscosity in the range of 0.05 to 1.5. The copolymer of the present embodiment is usually obtained in the form of powder having a size of about 16 to 60 meshes.

In the present embodiment, the neutralized salt of the copolymer is preferably that the active hydrogen of the carbonylic acid produced from the maleic acid reacts with the basic substance to form a salt to form a neutralized product. In the neutralized product of the? -Olefin-maleic acid copolymer used in the present embodiment, from the viewpoint of binding property as a binder, any of the basic substance containing a monovalent metal and ammonia, Is preferably used. That is, the neutralized salt of the? -Olefin-maleic acid copolymer of the present embodiment is a neutralized salt of an? -Olefin-maleic acid with a basic substance containing a monovalent metal or a neutralization salt of? -Olefin-maleic acid with ammonia Salt or a mixture thereof.

The degree of neutralization is not particularly limited, but when it is used as a binder, it is preferably in the range of 0.3 to 1 mole relative to 1 mole of carboxylic acid generated from the maleic acid in consideration of the reactivity with the electrolytic solution, More preferably in the range of 0.4 to 1 mole, is preferably used. With such neutralization degree, the pH of the binder composition of the present embodiment can be adjusted to a predetermined range, and the acidity is low, which is advantageous in inhibiting decomposition of the electrolyte solution.

In the present embodiment, the degree of neutralization can be determined by a method such as titration with a base, infrared spectrum, or NMR spectrum. However, in order to measure a neutralization point easily and accurately, it is preferable to carry out titration with a base. The specific titration method is not particularly limited, but it can be carried out by dissolving in water with a small amount of impurities such as ion-exchanged water, and neutralizing it with a basic substance such as lithium hydroxide, sodium hydroxide or potassium hydroxide. The indicator of the neutralization point is not particularly limited, but an indicator such as phenolphthalein, which indicates the pH with a base, can be used.

In the present embodiment, the amount of the basic substance to be used is not particularly limited and may be suitably selected according to the purpose of use, but is usually preferably 0.1 to 2 moles per 1 mole of the maleic acid unit in the maleic acid copolymer. If such an amount is used, it is considered that the pH of the binder composition of the present embodiment can be adjusted to a predetermined range. When the amount of the monovalent metal-containing basic substance used is preferably 0.6 to 2.0 moles, more preferably 0.7 to 2.0 moles per mole of maleic acid unit in the maleic acid copolymer, the residual amount of alkali is small A water-soluble copolymer salt can be obtained.

The reaction of the? -olefin-maleic acid copolymer and the basic substance can be carried out according to a conventional method, but the method of carrying out the reaction in the presence of water and obtaining a neutralized product of the? -olefin-maleic acid copolymer as an aqueous solution is simple , desirable.

Examples of the basic substance containing a monovalent metal usable in the present embodiment include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide; Carbonates of alkali metals such as sodium carbonate and potassium carbonate; Acetic acid salts of alkali metals such as sodium acetate and potassium acetate; And phosphates of an alkali metal such as trisodium phosphate.

Examples of amines such as ammonia include primary amines such as ammonia, methylamine, ethylamine, butylamine and octylamine; secondary amines such as dimethylamine, diethylamine and dibutylamine; amines such as trimethylamine, And tertiary amines such as amine. Of these, ammonia, lithium hydroxide, sodium hydroxide and potassium hydroxide are preferable as the basic substance. Particularly, as a binder for a lithium ion secondary battery, use of ammonia or lithium hydroxide is preferable. The monovalent metal-containing basic substance and / or ammonia may be used alone or in combination of two or more. Also, if it is within a range not adversely affecting battery performance, a neutralization product of an? -Olefin-maleic acid copolymer may be prepared by using a basic substance containing an alkali metal hydroxide such as sodium hydroxide or the like in combination.

The nonaqueous electrolyte battery using the binder composition of the present embodiment has excellent electrical characteristics because it contains the neutralized salt of the? -Olefin-maleic acid copolymer in which the? -Olefins and the maleic acid are copolymerized as described above.

Next, the binder composition of the present embodiment further contains a crosslinking agent. By including the crosslinking agent, the binder composition can be imparted with adhesiveness and toughness. Incidentally, the binder composition of the present embodiment includes polyamines as a cross-linking agent. That is, the binder composition of the present embodiment has a structure in which a neutralized salt of an? -Olefin-maleic acid copolymer as described above is crosslinked with polyamines.

As the polyamine as the crosslinking agent used in the present embodiment, any polyamine can be used without limitation as long as it is electrochemically stable. For example, a polyamine high molecular weight substance having a molecular weight of 500 or more can be used.

Specific examples of the polyamine high molecular weight substance include an amino group-containing polymer, and preferable specific examples thereof include polyethyleneimine, polytetramethyleneimine, polyvinylamine, polyallylamine, polydialylarylamine, polydimethylallylamine , Dicyandiamide-formalin condensates, dicyandiamide-alkylene (polyamine) condensates, and the like. These may be used alone or plural ones may be used. In consideration of availability and economy, use of polyethyleneimine (PEI), polyallylamine, polydialylamine is preferred.

The molecular weight of these polyamines is not particularly limited, and the average molecular weight is in the range of 500 to 50000, more preferably 1000 to 30,000, and most preferably 1500 to 25000. The amount of the polyamine to be added is not particularly limited but is usually 0.05 to 30 parts by weight, more preferably 0.3 to 10 parts by weight, per 100 parts by weight of the? -Olefin-maleic acid copolymer (solid content) Most preferably in the range of 0.6 to 5 parts by weight. When the addition amount of the polyamine is in the range of 0.05 to 30 parts by weight, it is considered that the viscosity of the obtained binder composition is easily adjusted to a desired range. In addition, too large an addition amount is not preferable because the resistance component increases, and an excessively small addition amount is not preferable because adhesion and toughness can not be imparted.

In the present embodiment, the polyamines may be added and reacted with the alpha -olefin-maleic acid copolymer and a basic substance containing a monovalent metal, or the alpha -olefin-maleic acid copolymer and the monovalent metal May be added after the reaction with the basic substance.

Next, in the present embodiment, the exchange ratio (opening ratio) of the copolymer indicates the degree of hydrolysis of the maleic anhydride moiety polymerized with the? -Olefins when maleic anhydride is used as the maleic acid. In the copolymer of the present embodiment, the preferred exchange ratio is 60 to 100%, more preferably 70 to 100%, and even more preferably 80 to 100%. If the exchange ratio is too low, the degree of structural flexibility of the copolymer becomes small and the stretchability becomes insufficient, so that the force for bonding the polar particles to be adhered may be small, which is not preferable. In addition, there is a concern that the affinity to water is low and the solubility is insufficient. The conversion ratio can be determined by, for example, measuring the hydrogen at the α-position of the substituted maleic acid based on the hydrogen located at the α-position of maleic anhydride, by measuring the ratio by 1 H-NMR, The ratio may be determined by IR measurement of the carbonyl group derived from the converted maleic anhydride.

In the present embodiment, when the maleic acid is maleic anhydride, the neutralized salt of the copolymer means that the active hydrogen of the carbonylic acid produced by ring opening of maleic anhydride reacts with the basic substance as described above, It forms a salt and becomes a neutralized product. The degree of neutralization in this case is not particularly limited, but when it is used as a binder, it is preferably in the range of 0.2 to 0.8 mol relative to 1 mol of the carbonyl group generated by ring opening in consideration of the reactivity with the electrolytic solution, More preferably in the range of 0.4 to 0.7 mol, is preferably used. Such a degree of neutralization lowers the acidity and has an advantage of inhibiting decomposition of the electrolytic solution. The neutralization degree of the copolymer in the case of using maleic anhydride can be measured by the same method as the above-mentioned method.

As described above, in the present embodiment, in the aqueous solution containing 10 wt% of the neutralized salt of the binder composition, the viscosity at 25 ° C and the shear rate of ^{40 s -1} , measured by a Brookfield viscometer Is in the range of 1800 mPa · s to 15000 mPa · s. The viscosity is more preferably in the range of 2000 mPa · s to 12000 mPa · s. By setting the viscosity within such a range, it is considered that the battery characteristics can be improved without deteriorating the binding property and toughness of the binder. On the other hand, if the viscosity is less than 1800 mPa, the coating property when the slurry described later is produced is poor, and it is not possible to coat the slurry to a required thickness, and flexibility may not be imparted. On the other hand, when the viscosity is higher than 12000 mPa · s, it becomes difficult to handle in the manufacturing process, and when mixing with the active material or the conductive additive, it may not be uniformly mixed.

In the present embodiment, the viscosity of the aqueous solution of the binder composition can be adjusted, for example, by adjusting the molecular weight and neutralization degree of the copolymer, the amount of addition of polyamines and the molecular weight, or adjusting the neutralization (pH) The amount can be adjusted to the above range by increasing the amount of acid, adding a thickener, etc., but is not limited thereto.

The viscosity in the present embodiment can be measured by, for example, a rotational viscometer method.

Further, the binder composition of the present embodiment is preferably a hydrogel.

Presently known water-soluble polymers such as starch, carrageenan, fibrin derivatives, gelatin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid and polyoxyethylene oxide . Hydrogels using these water-soluble polymers are widely used for applications such as preservatives, fire retardants, insulating materials, and cold insulation materials.

However, hydrogels using these water-soluble polymers are generally complicated. For example, it is necessary to control the temperature stepwise or the like (JP-A-2013-234280, etc.), or a gelling reaction at a high temperature is required, or a stable hydrogel can not be formed unless the temperature is lower than 0 ° C, It is necessary to promote the gelation reaction by strictly adjusting the pH of the aqueous solution (Japanese Patent Laid-Open No. 2009-536940, etc.), and the production method of the hydrogel which can gel easily is small . In addition, when the hydrogel has a large water content, the gelation reaction is often slow, so that a mesh structure can not be formed in a short time and the desired performance can not be exhibited in some cases.

In the present embodiment, a hydrogel obtained from the binder composition described above as a raw material is also included as a preferred embodiment. According to this embodiment, it is possible to provide a hydrogel in which the manufacturing method is comparatively simple and the characteristics of the secondary battery can be improved.

The hydrogel of the present embodiment has a structure in which the neutralized salt of an? -Olefin-maleic acid copolymer in which? -Olefins and maleic acid are copolymerized as described above is crosslinked with a crosslinking agent such as polyamines, And has a transmittance of 40 to 85% in a visible light region (400 to 800 nm) of an aqueous solution. Here, the 10 wt% aqueous solution means that the solids content of the binder composition forming the hydrogel as solid content not containing water is 10 wt%.

In the present embodiment, the hydrogel refers to a structure in which a solvent containing water as a main component is collected in a mesh structure formed by crosslinking a polymer. The amount of the solvent contained in the hydrogel of the present embodiment is not particularly limited as long as the transmittance falls within the above-mentioned range. The solvent collected in the mesh structure may contain a solvent which is soluble in water or a solvent which is miscible with water so as not to affect the effect of the present invention. The network structure means a structure similar to a mesh of a net surrounded by a three-dimensional structure by crosslinking an? -Olefin-maleic acid copolymer in which? -Olefins and maleic acid are copolymerized. Thus, flexibility can be imparted to the hydrogel.

In the hydrogel of the present embodiment, the transmittance of the 10 wt% aqueous solution in the visible light region (400 to 800 nm) is preferably in the range of 40 to 85%, more preferably in the range of 50 to 75% And more preferably in the range of 45 to 70%.

In the present embodiment, the transmittance refers specifically to the transmittance in a visible light region of 400 to 800 nm when measured in a 10 mm cell using an ultraviolet / visible spectrophotometer, for example. When the transmittance is higher than 85%, the network structure is not sufficiently formed, and the hydrogel can not be formed. When the transmittance is higher than 85%, the crosslinking degree is low and the network structure is not developed, so that the polymer chain does not spread in the electrode surface, and the particles in the mixed layer can not be spatially bonded to each other, Throw away. On the other hand, if the transmittance is lower than 40%, the crosslinking proceeds too much to increase the viscosity and the productivity is deteriorated. On the other hand, if the transmittance is too low, the network structure becomes too developed, so that it becomes impossible to sufficiently dissolve the solid component in the slurry production, and the binder (hydrogel as the binder) Resulting in deterioration of properties and flexibility, which may cause deterioration of battery characteristics.

That is, in the hydrogel of the present embodiment, the transmittance in the visible light region (400 to 800 nm) of the 10 wt% aqueous solution is in the range of 40 to 85%, which means that the neutralized salt of the -olefin- It has a reasonable degree of network structure by being crosslinked to an appropriate degree. By having such a moderate degree of network structure, there is an advantage that it is not necessary to use a large amount of crosslinking agent which is normally required. Generally, if a large amount of crosslinking agent is added, problems such as an increase in swelling property due to a network structure or an increase in resistance due to a crosslinking agent may occur. However, in the present embodiment, these disadvantages do not occur.

Further, in the present embodiment, the permeability of the hydrogel is determined by a method such as the kind of a cross-linking agent (for example, polyamines) to be described later, the molecular weight, the amount of addition, and the degree of neutralization of the neutralized salt of the- As shown in FIG.

The method for obtaining the hydrogel of the present embodiment is not particularly limited. For example, the neutralized salt of the -olefin-maleic acid copolymer as described above is mixed with the cross-linking agent as described above, , And heating and stirring at about 60 to 90 DEG C for 1 to 8 hours. That is, the binder composition of the present embodiment is obtained by using, as a raw material, for example, heating and stirring as described above.

The hydrogel of this embodiment specifies the transmittance in the case of 10 wt% aqueous solution as solids (i.e., when the amount of water is 90 wt%), but the amount of water contained in the hydrogel in this embodiment is, But is not limited to 90% by weight as long as the effect of the present invention is exhibited. The amount of water contained in the hydrogel is preferably 3% by weight to 20% by weight, more preferably 5% by weight to 15% by weight.

The binder composition to be used as the hydrogel raw material of the present embodiment is preferably a viscosity before heating for preparing the hydrogel and has a viscosity in the same range as that of the binder composition of the present embodiment described above, It is preferable that the viscosity of the 10 wt% aqueous solution at 25 ° C and the shear rate of 40 s ^-1 is 2300 mPa · s to 15000 mPa · s. If the viscosity is too low, the network structure is not sufficiently formed, and the hydrogel can not be formed. If the viscosity is too high, kneading of the slurry can not be performed sufficiently, which not only becomes an unstable slurry but also makes it difficult to form an electrode, which causes an increase in electrical resistance. The viscosity in the present embodiment can be measured by, for example, a rotational viscometer method.

In most cases, the binder composition for the non-aqueous electrolyte cell electrode is used in the production of the slurry composition in the state of containing water. At this time, in the binder composition for a nonaqueous electrolyte battery electrode, the binder may be diluted with water from the viewpoint of viscosity adjustment and production, and the hydrogel may be broken. The hydrogel of the present embodiment may be further diluted with a solvent such as water in the subsequent production of the slurry composition, and the hydrogel itself may be pulverized for viscosity adjustment.

In the present embodiment, the method of diluting or cracking the crosslinked binder composition or the hydrogel is not particularly limited as long as an aqueous solution of the uniform binder composition can be obtained. For example, a method using a rotary type mixer, a planetary mixer, a planetary ball mill, a bead mill or the like may be used.

The binder composition for a nonaqueous electrolyte battery electrode of the present embodiment is usually used as a slurry composition for a nonaqueous electrolyte battery electrode (hereinafter, simply referred to as a slurry composition), which further contains an active material and water, in addition to the above- . It is also preferable that the hydrogel of the present embodiment is further used as a slurry composition for a nonaqueous electrolyte battery electrode containing an active material. The slurry composition containing the hydrogel may be further added with water at the time of preparation.

In the present embodiment, the nonaqueous electrolyte battery negative electrode is characterized in that the current collector is formed by binding a mixed layer containing at least the binder composition (or hydrogel) of the present embodiment and the active material. This negative electrode can be formed by applying the above slurry composition to a current collector and then removing the solvent by a method such as drying. If necessary, a thickener, a conductive additive and the like may be further added to the mixed layer.

In the slurry composition for a non-aqueous electrolyte cell electrode, the amount of the neutralized salt of the -olefin-maleic acid copolymer to 100 parts by weight of the active material is preferably 0.4 to 15 parts by weight, more preferably 0.6 to 10 parts by weight More preferably 1 to 8 parts by weight. If the amount of the copolymer is excessively small, the viscosity of the slurry may be too low to reduce the thickness of the mixed layer. Conversely, if the amount of the copolymer is excessively large, the discharge capacity may decrease.

On the other hand, the amount of water in the slurry composition is preferably 40 to 150 parts by weight, more preferably 70 to 130 parts by weight, based on 100 parts by weight of the active material.

Examples of the solvent in the negative electrode slurry composition of the present embodiment include alcohols such as methanol, ethanol, propanol and 2-propanol, cyclic ethers such as tetrahydrofuran and 1,4-dioxane , Amides such as N, N-dimethylformamide and N, N-dimethylacetamide, cyclic amides such as N-methylpyrrolidone and N-ethylpyrrolidone, sulfoxides such as dimethylsulfoxide and the like May be used. Of these, use of water is preferable from the viewpoint of safety.

In addition to water as a solvent for the negative electrode slurry composition of the present embodiment, the following organic solvents may be used in combination within a range of preferably 20% by weight or less of the total solvent. As such an organic solvent, those having a boiling point at normal pressure of 100 占 폚 or more and 300 占 폚 or less are preferable, and for example, hydrocarbons such as n-dodecane; 2-ethyl-1-hexanol, and 1-nonanol; esters such as? -butyrolactone and methyl lactate; Amides such as N-methylpyrrolidone, N, N-dimethylacetamide and dimethylformamide; And organic dispersants such as sulfoxides and sulfones such as dimethylsulfoxide and sulfolane.

Examples of the active material (negative electrode active material) added to the negative electrode slurry composition in the case where the slurry composition of the present embodiment is used for the negative electrode include amorphous carbon, graphite, natural graphite, mesocarbon microbeads (MCMB) Carbonaceous materials such as carbon fibers; Conductive polymers such as polyacene; Metal oxides such as SiOx, SnOx, and LiTiOx; other metal oxides; lithium-based metals such as lithium metal and lithium alloy; TiS ₂ , LiTiS _2, and the like.

In the present embodiment, a thickener may be further added to the slurry composition, if necessary. The thickening agent which can be added is not particularly limited, and various alcohols, particularly polysaccharides such as polyvinyl alcohol and its modified products, cellulose, and starch can be used.

Examples of the conductive additive to be incorporated in the slurry composition according to need include metal powder, conductive polymer, and acetylene black. The amount of the conductive additive to be used is preferably 0.1 to 10 parts by weight, more preferably 0.8 to 7 parts by weight, based on 100 parts by weight of the negative electrode active material.

The current collector used in the nonaqueous electrolyte battery negative electrode of the present embodiment is not particularly limited as long as it is made of a conductive material. Examples of the current collector include iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, May be used. These may be used singly or in combination of two or more in an arbitrary ratio.

Particularly, when copper is used as the negative electrode, the effect of the slurry for a non-aqueous electrolyte battery negative electrode of the present invention is most evident. The shape of the current collector is not particularly limited, but it is usually preferable that the current collector has a sheet shape with a thickness of about 0.001 to 0.5 mm.

The method of applying the slurry to the current collector is not particularly limited. For example, methods such as a doctor blade method, a dipping method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a dipping method, and a brush coating method can be used. Although the amount to be applied is not particularly limited, the thickness of the mixed layer including the active material, the conductive additive, the binder and the thickening agent formed after removing the solvent or the dispersion medium by a method such as drying is preferably 0.005 to 5 mm, more preferably 0.01 ~ 2 mm is common.

The method of drying the solvent such as water contained in the slurry composition is not particularly limited, and examples thereof include air drying by hot air, hot air, low-humidity air; Vacuum drying; Infrared ray, far-infrared rays, and electron rays. The drying conditions may be adjusted so that the solvent can be removed as soon as possible while the active material layer is cracked due to stress concentration or the speed range is such that the active material layer is not peeled off from the current collector. In order to increase the density of the active material of the electrode, it is effective to press the current collector after drying. Examples of the pressing method include a die press and a roll press.

The present invention also includes a nonaqueous electrolyte battery having the negative electrode. The non-aqueous electrolyte cell generally includes the negative electrode, the positive electrode, and an electrolytic solution.

In the present embodiment, the positive electrode is a positive electrode usually used for a nonaqueous electrolyte battery such as a lithium ion secondary battery, without any particular limitation. Examples of the positive electrode active material include transition metal oxides such as TiS ₂ , TiS ₃ , amorphous MoS ₃ , Cu ₂ V ₂ O ₃ , amorphous V ₂ OP ₂ O ₅ , MoO ₃ , V ₂ O ₅ and V ₆ O ₁₃ Lithium-containing composite metal oxides such as LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , and LiMn ₂ O ₄ are used. The positive electrode active material may be mixed with a binder such as SBR, NBR, acrylic rubber, hydroxyethyl cellulose, carboxymethyl cellulose, or polyvinylidene fluoride in the same manner as the negative electrode, A positive electrode slurry prepared by mixing at 100 ° C or higher and 300 ° C or lower is applied to a positive electrode current collector such as aluminum and the solvent is dried to form a positive electrode.

In the non-aqueous electrolyte cell of the present embodiment, an electrolytic solution in which an electrolyte is dissolved in a solvent may be used. The electrolytic solution may be either liquid or gelled as long as it is used in a non-aqueous electrolyte cell such as a conventional lithium ion secondary battery, and may be suitably selected to exhibit its function as a battery depending on the type of the negative electrode active material and the positive electrode active material. As specific examples of the electrolyte, any of conventionally known lithium salts may be used, and LiClO ₄ , LiBF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiB ₁₀ Cl _{10 , LiAlC l4, LiCl, LiBr,} LiB (C 2 H 5) 4, CF 3 SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3, LiC 4 F 9 SO 3, Li (CF 3 SO 2) 2 N , Lower aliphatic carboxylic acid lithium, and the like.

The solvent (electrolytic solution solvent) for dissolving such an electrolyte is not particularly limited. Specific examples thereof include carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate and diethyl carbonate; lactones such as? -butyllactone; Ethers such as trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran and 2-methyltetrahydrofuran; Sulfoxides such as dimethyl sulfoxide; 1,3-dioxolane, 4-methyl-1,3-dioxolane and the like; Nitrogen-containing compounds such as acetonitrile and nitromethane; Organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; Inorganic acid esters such as triethyl phosphate, dimethyl carbonate, and diethyl carbonate; Diglyme; Triglyme; Sulfolanes; Oxazolidinones such as 3-methyl-2-oxazolidinone; 1,3-propane sultone, 1,4-butane sultone, and naphtha sultone. These may be used singly or in combination of two or more. When a gel-like electrolytic solution is used, a nitrile-based polymer, an acrylic polymer, a fluorine-based polymer, an alkylene oxide-based polymer, or the like can be added as a gelling agent.

The method for producing the nonaqueous electrolyte battery of the present embodiment is not particularly limited, and for example, the following manufacturing method is exemplified. That is, the negative electrode and the positive electrode are overlapped with each other with a separator such as a polypropylene porous membrane interposed therebetween, and wound or folded in accordance with the shape of the battery, placed in a battery container, and an electrolyte is injected and sealed. The shape of the battery may be a known coin type, a button type, a sheet type, a cylindrical shape, a square shape, a flat shape, or the like.

The nonaqueous electrolyte battery of the present embodiment is a battery that combines adhesiveness and improvement of battery characteristics, and is useful for various applications. For example, it is very useful as a battery for use in a portable terminal requiring miniaturization (lightening and thinning), high performance (high output, high capacity, low resistance, long life).

Although the present specification discloses various techniques as described above, the main techniques among them are summarized below.

That is, the binder composition for a nonaqueous electrolyte battery electrode according to one aspect of the present invention (hereinafter, simply referred to as a binder composition) is prepared by dissolving a neutralized salt of an? -Olefin-maleic acid copolymer in which? -Olefins and maleic acid are copolymerized, A binder composition for a non-aqueous electrolyte cell electrode comprising a structure crosslinked by amines, wherein the aqueous solution containing 10 wt% of the binder composition has a viscosity at 25 ° C and a shear rate of ^{40 s -1} of 1800 mPa · s to 15000 mPa · s s.

By such a constitution, it is considered that the battery characteristics can be improved without damaging the binding between the active material and the collector electrode and the toughness as an electrode.

Further, it is preferable that a hydrogel having a transmittance of 40 to 85% in a visible light region (400 to 800 nm) of a 10 wt% aqueous solution obtained from the binder composition is used.

According to the present embodiment, the three-dimensional network structure is developed and the transparent hydrogel can be provided by the above-described structure. By using the hydrogel, the hydrogel having excellent battery characteristics (low resistance) and functionality . In addition, the hydrogel of the present invention has an advantage that it can be obtained by a relatively simple manufacturing method.

The slurry composition for a non-aqueous electrolyte cell electrode according to still another aspect of the present invention is characterized by containing the above-mentioned binder composition and an active material.

A slurry composition for a non-aqueous electrolyte cell electrode according to another aspect of the present invention is characterized by containing the above-mentioned hydrogel and an active material.

A nonaqueous electrolyte battery negative electrode according to still another aspect of the present invention is characterized in that the current collector is formed by binding a binder layer for the nonaqueous electrolyte battery electrode and a mixed layer containing at least an active material.

A non-aqueous electrolyte cell negative electrode according to still another aspect of the present invention is characterized in that the current collector is formed by binding a hydrogel and a mixed layer containing at least an active material.

The non-aqueous electrolyte cell according to still another aspect of the present invention is characterized by having the non-aqueous electrolyte battery negative electrode.

Example

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

≪ Test Example 1 >

(Example 1)

≪ Preparation of binder composition >

A 10 wt% aqueous solution was prepared using a water-soluble lithium-modified isobutene-maleic anhydride copolymer resin (average molecular weight: 325,000, degree of neutralization of 0.5, and conversion rate of 96%) and used in the following test. The adjustment of the pH was carried out by adjusting the degree of neutralization of the copolymer resin, specifically by adding 1 equivalent (0.16 mol) of lithium hydroxide to the maleic acid unit in the maleic acid copolymer.

5 g of a 10 wt% aqueous solution of polyethyleneimine (PEI, average molecular weight 10,000, manufactured by Nippon Shokubai Co., Ltd.) as a crosslinking agent was added dropwise to 500 g of the 10 wt% aqueous solution of the resin at 0.5 ml / min and the mixture was heated and stirred at 60 캜 for 7 hours. Thereafter, the mixture was cooled to room temperature and used as a binder aqueous solution containing the binder composition.

≪ Measurement of viscosity of negative electrode binder composition >

The viscosity of the 10 wt% aqueous solution (binder aqueous solution) of the binder composition obtained above was measured at 25 캜 using a Brookfield viscometer (DV-I PRIME Brookfield). The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below.

<Dilution of Binder Solution>

An equivalent amount of water was added to the binder solution (binder aqueous solution) of 10 weight% prepared above and diluted with a planetary stirrer (ARE-250, Shinki) to obtain a binder composition of 5 wt% .

&Lt; Preparation of negative electrode slurry >

The slurry for the electrode was prepared by mixing 6.452 parts by weight of a 5 wt% aqueous solution of the binder composition for negative electrode as a solid component and 100 parts by weight of a natural graphite (DMGS, BYD) as a negative electrode active material, 1.075 parts by weight of P (manufactured by Timcal) was added to a dedicated vessel and kneaded using a planetary stirrer (ARE-250, manufactured by Shinki) to prepare an electrode coating slurry. The composition ratio of the active material and the binder in the slurry is a solid content of graphite powder: conductive auxiliary agent: binder composition = 100: 1.075: 6.452.

<Fabrication of battery negative electrode>

The obtained slurry was coated on a copper foil (CST8G, manufactured by Fukuda Metal &amp; Chemical Co., Ltd.) as a current collector by using a bar coater (T101, manufactured by Matsuo Industry Co., Ltd.). After primary drying at room temperature (24.5 DEG C) Ltd.). Thereafter, punching as a battery electrode (? 14 mm) was performed and secondary drying was performed under a reduced pressure condition at 140 占 폚 for 3 hours to prepare an electrode for a coin battery (negative electrode for battery).

<Preparation of Electrode for Peel Strength and Toughness Test>

The obtained slurry was coated on a copper foil (CST8G, manufactured by Fukuda Metal &amp; Chemical Co., Ltd.) as a current collector by using a bar coater (T101, manufactured by Matsuo Industry Co., Ltd.). After primary drying at room temperature (24.5 DEG C) (Thickness: about 50 占 퐉) which had been subjected to the rolling treatment by using a pressure-sensitive adhesive (trade name:

<Toughness Test of Electrodes>

The toughness of the electrode was evaluated using a type 1 test apparatus of JIS K5600-5-1 (General Test Methods for Paints - Part 5: Mechanical Properties of Coating Film - Section 1: Flexural Resistance (Cylindrical Mandrel Method) . The breakage of the electrode was visually confirmed, and no breakage occurred even when the minimum diameter was 2 mm in this test. Thus, an SUS rod (made of SUS304 Wire NIRACO) of 1.5 mm, 1.0 mm, 0.8 mm, and 0.5 mm was prepared and the electrode winding test was performed. The results of the smallest SUS diameter without cracking are shown in Table 1 below.

<Measurement of Peel Strength of Electrode>

And the strength when the electrode was peeled from the copper foil serving as the collector electrode was measured. The peel strength was measured with a load cell of 50 N (manufactured by Imada Co., Ltd.) at a 180 ° peel strength. The 180 degree peel strength (peel width 10 mm, peel rate 100 mm / min) was measured by applying the slurry application surface of the coated electrode for a battery to the stainless steel plate using a double-sided tape (double-sided tape on both sides). The results are shown in Table 1 below.

<Fabrication of Battery>

The coated electrode for a battery (negative electrode for a battery) obtained above was transferred to a glove box (made by Mihwa Manufacturing Co.) under an argon gas atmosphere. A metal lithium foil (thickness 0.2 mm,? 16 mm) was used for the positive electrode. The electrolytic solution was prepared by dissolving vinylene carbonate (VC) in ethylene carbonate (EC) and ethyl methyl carbonate (EMC) of lithium hexafluorophosphate (LiPF ₆ ) using polypropylene type (Cell Guard # 2400, polypore) as a separator. (1M-LiPF ₆ , EC / EMC = 3/7 vol% to 2% by weight of VC) to which a coin cell (2032 type) was added to prepare a coin cell (2032 type).

<Evaluation method: charge / discharge characteristic test>

The produced coin battery was subjected to a charge-discharge test using a commercial charge / discharge tester (TOSCAT3100, manufactured by TYOKYU SYSTEMS Co., Ltd.). The coin cell was placed in a constant temperature bath at 25 DEG C, and the battery was charged at a constant current of 0.1 C (about 0.5 mA / cm &lt; 2 &gt;) with respect to the amount of active material until the voltage became 0 V with respect to the lithium potential. And a constant-voltage charge of 0 V was carried out until the current. The capacity at this time was referred to as a charging capacity (mAh / g). Then, a constant current discharge of 0.1 C (about 0.5 mA / cm 2) to the lithium potential was carried out up to 1.5 V, and the capacity at this time was referred to as discharge capacity (mAh / g). The initial discharge capacity and the charge capacity difference were referred to as irreversible capacity, and the discharge capacity / charge capacity percentage was referred to as charge / discharge efficiency. The DC resistance of the coin cell was set to a resistance value after one charge (full charge state). The results are shown in Table 1 below.

(Example 2)

The binder composition was prepared in the same manner as in Example 1 so that the resin used in Example 1 and the crosslinking agent (PEI) were 10 wt% aqueous solution of resin: 10 wt% aqueous solution of PEI = 99.7: 0.3 Respectively. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below.

The slurry for the electrode was prepared by mixing 6.452 parts by weight of a 10% by weight aqueous solution of the binder composition for negative electrode as a solid component with 100 parts by weight of natural graphite (DMGS, BYD) as a negative electrode active material, 1.075 parts by weight of P (manufactured by Timcal Co., Ltd.) as solid content was charged into a dedicated vessel and kneaded using a planetary mixer (ARE-250, manufactured by Shinki) to prepare an electrode coating slurry (negative electrode slurry). The composition ratio of the active material and the binder in the slurry is a solid content of graphite powder: conductive auxiliary agent: binder composition = 100: 1.075: 6.452.

A coating negative electrode (negative electrode for battery) was produced in the same manner as in Example 1 to obtain a coin battery, and a charging / discharging characteristic test was conducted. The toughness test and the peel strength measurement were carried out by using a coated electrode (peel strength, toughness test electrode). The results are shown in Table 1 below.

(Example 3)

Using the resin and PEI used in Example 1, the binder composition was prepared in the same manner as in Example 1 so that the 10 wt% aqueous solution of resin: the 10 wt% aqueous solution of PEI = 98: 2. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. Thereafter, the binder composition was diluted by the same method as in Example 1 to obtain a binder composition of 5% by weight. Next, a slurry for a nonaqueous electrolyte battery electrode (negative electrode slurry) was prepared in the same manner as in Example 1 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

(Example 4)

A 10 wt% aqueous solution of a water-soluble lithium-modified isobutene-maleic anhydride copolymer resin (average molecular weight: 325,000, neutralization degree of 0.7, and 97 conversion rate) was prepared and lithium hydroxide was added in an amount of 1.4 equivalents relative to the maleic acid unit in the maleic acid copolymer The pH was adjusted by adding.

Using the resin and PEI used in Example 1, the binder composition was prepared in the same manner as in Example 1, so that the 10 wt% aqueous solution of resin: the 10 wt% aqueous solution of PEI = 99: 1. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. A slurry for a nonaqueous electrolyte battery electrode was prepared in the same manner as in Example 2 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

(Example 5)

Aqueous solution of a water-soluble lithium-modified isobutene-maleic anhydride copolymer resin (average molecular weight: 325,000, degree of neutralization of 0.4, conversion rate of 92%) was prepared, and lithium hydroxide was added in an amount of 0.8 equivalent to the maleic acid unit in the maleic acid copolymer The pH was adjusted by adding.

Using the resin and PEI used in Example 1, the binder composition was prepared in the same manner as in Example 1, so that the 10 wt% aqueous solution of resin: the 10 wt% aqueous solution of PEI = 99: 1. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. Thereafter, the binder composition was diluted by the same method as in Example 1 to obtain a binder composition of 5% by weight. Next, a slurry for a nonaqueous electrolyte battery electrode was prepared in the same manner as in Example 1 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

(Comparative Example 1)

A 10 wt% aqueous solution of the resin used in Example 1 was prepared and used as the negative electrode binder composition without adding PEI. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. A slurry for a nonaqueous electrolyte battery electrode was prepared in the same manner as in Example 2 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

(Comparative Example 2)

The binder composition was prepared in the same manner as in Example 1 so that the resin used in Example 1 and the crosslinking agent (PEI) were 10 wt% aqueous solution of resin: 10 wt% aqueous solution of PEI = 99.97: 0.03 Respectively. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. Thereafter, a slurry for a nonaqueous electrolyte battery electrode was prepared in the same manner as in Example 2 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

(Comparative Example 3)

Using the resin and PEI used in Example 1, the binder composition was prepared in the same manner as in Example 1 so that the 10 wt% aqueous solution of resin: the 10 wt% aqueous solution of PEI = 90: 10. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. Thereafter, the binder composition was diluted by the same method as in Example 1 to obtain a binder composition of 5% by weight. Next, a slurry for a nonaqueous electrolyte battery electrode was prepared in the same manner as in Example 1 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

(Comparative Example 4)

The binder composition was prepared in the same manner as in Example 1 so that the resin used in Example 1 and polyallylamine (molecular weight: 3000) were used so that the 10 wt% aqueous solution of the resin and the 10 wt% aqueous solution of PEI were 99: Preparation was carried out. The results of the viscosity at a shear rate of ^{40 s -1} are shown in Table 1 below. Thereafter, the binder composition was diluted by the same method as in Example 1 to obtain a binder composition of 5% by weight. Next, a slurry for a nonaqueous electrolyte battery electrode was prepared in the same manner as in Example 1 above. Further, a coated negative electrode was prepared by the same method as in Example 1, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, the toughness test and the peel strength measurement were carried out by using the coated electrode. The results are shown in Table 1 below.

[Table 1]

(Review)

Examples 1 to 5 (Comparative Examples 1 to 5) in which a crosslinking agent (polyamine) was contained in the negative electrode binder composition and an aqueous solution containing 10% by weight had a viscosity at 25 ° C and a shear rate of ^{40 s -1} at 1800 mPa · s to 12000 mPa · s , Toughness and adhesiveness were improved by the effect of crosslinking by the formation of an acid and a salt. Further, since the viscosity is increased by adding a cross-linking agent, slurry production becomes possible without using a thickening agent. As is clear from Table 1, even when a crosslinking agent is added, the resistance of the battery is not significantly affected and the resistance is reduced. On the other hand, in Comparative Example 1 in which polyamine was not contained, and Comparative Examples 2 to 4 in which the viscosity was outside the scope of the present invention even when polyamines were added, both toughness and adhesiveness were found to be low.

&Lt; Test Example 2 &

(Example 6)

&Lt; Preparation of hydrogel >

Aqueous solution of lithium-modified isobutene-maleic anhydride copolymer resin (average molecular weight: 325,000, degree of neutralization of 0.5, and conversion rate of 96%) was used and used in the following test.

A 10 wt% aqueous solution of polyethyleneimine (PEI, average molecular weight 10,000, manufactured by Nippon Shokubai Co., Ltd.) as a crosslinking agent and an aqueous solution of 10 wt% resin: PEI 10 wt% aqueous solution = 99.34: 0.66 were added to a 10 wt% aqueous solution of the resin, (Made by WARING STAND MIXER, manufactured by WARING) while being stirred at 2.0 ml / h. Thereafter, the mixture was heated and stirred at 90 DEG C for 2 hours to obtain a hydrogel.

<Measurement of transmittance>

The transmittance of the obtained hydrogel was measured with an ultraviolet / visible spectrophotometer (UV-2600 series, Shimadzu Corporation) using a 10 mm cell. Table 2 shows the lowest transmittance values in the visible light region between 400 nm and 800 nm as a result.

&Lt; Measurement of viscosity of hydrogel &

The viscosity of the 10 wt% aqueous solution of the hydrogel after the polyethyleneimine addition (before heating) was measured at 25 캜 using a Brookfield viscometer (DV-I PRIME Brookfield Co.). The viscosity results at shear rate of ^{40 s -1} are shown in Table 2 below.

<Dilution of hydrogel>

An equivalent amount of water was added to the 10 wt% hydrogel thus prepared, and a 5 wt% binder solution for the negative electrode was obtained using a hand mixer (WARING STAND MIXER, manufactured by WARING).

&Lt; Preparation of negative electrode slurry >

A slurry for electrode coating was prepared in the same manner as in Test Example 1 (Example 1) except that a 5 wt% aqueous solution of hydrogel was used instead of the 5 wt% aqueous solution of the negative electrode binder composition. The composition ratio of the active material and the hydrogel in the slurry is a solid content of graphite powder: conductive auxiliary agent: hydrogel (weight as binder composition excluding moisture) = 100: 1.075: 6.452.

<Fabrication of battery negative electrode>

An electrode for a coin battery (negative electrode for a battery) was fabricated in the same manner as in Test Example 1 (Example 1).

<Preparation of Flexible (Toughness) Test Electrodes>

The test was carried out using an electrode fabricated in the same manner as in < preparation of electrode for peel strength and toughness test of Test Example 1 (Example 1).

&Lt; Flexibility (Toughness) Test of Electrodes >

The flexibility (toughness) of the electrode was evaluated in the same manner as the toughness test of the electrode of Test Example 1 (Example 1). The results are shown in Table 2 below.

<Fabrication of Battery>

A coin cell (2032 type) was fabricated in the same manner as in the toughness test of the electrode of Test Example 1 (Example 1).

<Evaluation method: charge / discharge characteristic test>

The same charge / discharge test as in Test Example 1 was performed on the produced coin battery. The results are shown in Table 2 below.

(Example 7)

A hydrogel was prepared using the resin and the crosslinking agent (PEI) used in Example 6 so that the aqueous solution of 10 wt% of resin and the aqueous solution of 10 wt% of PEI were 99: 1, and the permeability and The viscosity was measured. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a nonaqueous electrolyte battery (negative electrode slurry) were prepared in the same manner as in Example 6. [ Further, a coated negative electrode (battery negative electrode) was produced by the same method as in Example 6 to obtain a coin battery, and a charge / discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode (peel strength, toughness test electrode). The results are shown in Table 2 below.

(Example 8)

Aqueous solution of a water-soluble lithium-modified isobutene-maleic anhydride copolymer resin (average molecular weight: 325,000, degree of neutralization of 0.7, conversion rate of 97%) was prepared.

A hydrogel was prepared by using the resin aqueous solution and the PEI used in Example 6 so as to make a 10 wt% aqueous solution of resin: 10 wt% aqueous solution of PEI = 99: 1, and a hydrogel was prepared in the same manner as in Example 6, The viscosity was measured. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Example 9)

Aqueous solution of a water-soluble lithium-modified isobutene-maleic anhydride copolymer resin (average molecular weight: 325,000, degree of neutralization: 0.4, conversion rate: 92%) was prepared.

A hydrogel was prepared in the same manner as in Example 6 to prepare a 10% by weight aqueous solution of resin and 10% by weight aqueous solution of PEI in an amount of 99: 1 by using the resin aqueous solution and PEI used in Example 6, Respectively. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Example 10)

A hydrogel was prepared in the same manner as in Example 6, using the resin used in Example 8 and a crosslinking agent (polyallylamine, molecular weight: 3,000) so as to obtain a 10 wt% aqueous solution of resin and a 10 wt% aqueous solution of PEI of 99.34: And the transmittance and the viscosity were measured. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Example 11)

A 10 wt% aqueous solution of a water-soluble lithium-modified methyl vinyl ether-maleic anhydride copolymer resin (average molecular weight: 630,000, neutralization degree of 0.5, and conversion rate of 96%) was prepared as a negative electrode binder composition.

Using the resin and PEI used in Example 6, a hydrogel was prepared in the same manner as in Example 6 so as to obtain a 10 wt% aqueous solution of resin: 10 wt% aqueous solution of PEI of 95: 5, and the transmittance and viscosity Respectively. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Example 12)

A 10% by weight aqueous solution of a water-soluble lithium-modified ethylene-maleic anhydride copolymer resin (average molecular weight: 350,000, degree of neutralization of 0.5, and conversion rate of 96%) was prepared.

A hydrogel was prepared by using the resin aqueous solution and the PEI used in Example 6 to obtain a 10 wt% aqueous solution of resin: 10 wt% aqueous solution of PEI of 95: 5 in the same manner as in Example 6, and the transmittance and viscosity Were measured. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Comparative Example 5)

A hydrogel was prepared by using the resin and the crosslinking agent (PEI) used in Example 6 so as to obtain a 10 wt% aqueous solution of resin: 10 wt% aqueous solution of PEI of 90: 10 in the same manner as in Example 6, The viscosity was measured. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Comparative Example 6)

Using a resin and a crosslinking agent (PEI, molecular weight: 600) used in Example 7, a hydrogel was prepared in the same manner as in Example 7, and the transmittance and the viscosity were measured. The results are shown in Table 2 below. Thereafter, dilution of the hydrogel and a slurry for a non-aqueous electrolyte cell were prepared in the same manner as in Example 6. [ Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Comparative Example 7)

The transmittance and viscosity of a 10 wt% aqueous solution of the resin used in Example 6 (without additive) were measured and the results are shown in Table 2 below. Thereafter, a slurry for a nonaqueous electrolyte battery was prepared in the same manner as in Example 6, except that the 10 wt% aqueous solution was used as a binder solution. Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Comparative Example 8)

The transmittance and viscosity of a 10 wt% aqueous solution (without additive) of the resin used in Example 10 were measured and the results are shown in Table 2 below. Thereafter, a slurry for a nonaqueous electrolyte battery was prepared in the same manner as in Comparative Example 7. Then, a coated negative electrode was prepared in the same manner as in Example 6 to obtain a coin battery, and a charging / discharging characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Comparative Example 9)

Table 2 shows the results of measuring the viscosity and the transmittance of a 10 wt% aqueous solution (without additive) of the resin used in Example 11. Thereafter, a slurry for a nonaqueous electrolyte battery was prepared in the same manner as in Comparative Example 7. Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

(Comparative Example 10)

(TRD2001, 48.3% by weight) which is a conventional aqueous negative electrode binder composition and CMC-Na (Serogens BSH-6, 10% by weight) as a thickener were used in the same manner as in Comparative Example 7, To prepare a battery slurry. The composition ratio of the active material and the binder in the slurry was a solid content of graphite powder: conductive auxiliary agent: SBR: CMC-Na = 100: 1.053: 3.158: 1.053. Further, a coated negative electrode was prepared by the same method as in Example 6, and a coin cell was obtained, and a charge-discharge characteristic test was conducted. Further, a flexibility test was conducted using a coated electrode. The results are shown in Table 2 below.

[Table 2]

(Review)

It has been found that by using the hydrogel having the predetermined transmittance of the present invention, an electrode having higher flexibility (toughness) can be produced. Further, according to the present invention, even when a crosslinking agent for hydrogeling is added, it exhibits low resistance equivalent to that of the untreated products of Comparative Examples 7 to 9, and is lower than that of the SBR-CMC system which is the conventional binder shown in Comparative Example 10, And it contributes to the improvement of the characteristics. On the other hand, in the hydrogels of Comparative Examples 6 to 9 having high transmittance, the flexibility could not be sufficiently provided. In Comparative Example 5, in which the addition amount of the cross-linking agent was high and the transmittance was low, the viscosity was very high, and the slurry could not be sufficiently crushed during the slurry production, resulting in a high resistance cell. Further, in Comparative Example 6 in which the molecular weight of the polyamines was low, since the degree of crosslinking was insufficient, the viscosity was low and sufficient flexibility could not be imparted.

This application is based on Japanese Patent Application No. 2016-231352 filed on November 29, 2016 and Japanese Patent Application No. 2016-242847 filed on December 15, 2016, the content of which is incorporated herein by reference will be.

In order to describe the present invention, the present invention has been appropriately and fully explained through the embodiments with reference to specific examples and the like in the foregoing description. However, those skilled in the art can easily change and / or improve the above-described embodiments It should be recognized. Accordingly, unless a person skilled in the art is of a type or mode of modification that does not fall within the scope of the claims of the claims, the mode of modification or the mode of modification is to be construed as being covered by the scope of the claims.

Industrial availability

INDUSTRIAL APPLICABILITY The present invention has wide industrial applicability in the technical field of a nonaqueous electrolyte battery such as a lithium ion secondary battery.

Claims (7)

A binder composition for a nonaqueous electrolyte battery electrode comprising a structure obtained by crosslinking a neutralized salt of an? -olefin-maleic acid copolymer in which? -olefins and maleic acid are copolymerized with polyamines, wherein the binder composition contains 10% Wherein the aqueous solution has a viscosity at 25 ° C and a shear rate of 40 s ^-1 of 1800 mPa · s to 15000 mPa · s. A hydrogel having a transmittance of 40 to 85% in a visible light region (400 to 800 nm) of a 10 wt% aqueous solution obtained from the binder composition of Claim 1. A slurry composition for a nonaqueous electrolyte battery electrode, comprising the binder composition according to any one of claims 1 to 7 and an active material. A slurry composition for a nonaqueous electrolyte battery electrode, comprising the hydrogel according to claim 2 and an active material. A negative electrode for a nonaqueous electrolyte battery comprising a current collector and a mixed layer containing the binder composition of claim 1 and an active material. A negative electrode for a nonaqueous electrolyte battery comprising a current collector and a mixed layer containing the hydrogel according to claim 2 and an active material. A nonaqueous electrolyte battery having the negative electrode for a nonaqueous electrolyte battery according to claim 5 or 6.