WO2018168520A1

WO2018168520A1 - Binder composition for non-aqueous electrolyte batteries, and binder aqueous solution for non-aqueous electrolyte batteries, slurry composition for non-aqueous electrolyte batteries, electrode for non-aqueous electrolyte batteries and non-aqueous electrolyte battery each utilizing said binder composition

Info

Publication number: WO2018168520A1
Application number: PCT/JP2018/007981
Authority: WO
Inventors: 有紀太田; 雄介天野; 岩崎　秀治
Original assignee: 株式会社クラレ
Priority date: 2017-03-16
Filing date: 2018-03-02
Publication date: 2018-09-20
Also published as: TW201840045A; JP7110170B2; TWI795390B; JPWO2018168520A1

Abstract

The present invention relates to: a binder composition for non-aqueous electrolyte batteries, characterized by containing (A) polyvinyl alcohol and (B) at least one component selected from a copolymer of vinyl alcohol and an ethylenically unsaturated carboxylic acid and neutralized salts thereof; and a binder aqueous solution for non-aqueous electrolyte batteries, a slurry composition for non-aqueous electrolyte batteries, an electrode for non-aqueous electrolyte batteries, a non-aqueous electrolyte battery and the like, in each of which the binder composition is used.

Description

Nonaqueous electrolyte battery binder composition, nonaqueous electrolyte battery binder aqueous solution, nonaqueous electrolyte battery slurry composition, nonaqueous electrolyte battery electrode, and nonaqueous electrolyte battery using the same

The present invention relates to a binder composition for a nonaqueous electrolyte battery, a binder aqueous solution for a nonaqueous electrolyte battery, a slurry composition for a nonaqueous electrolyte battery, a nonaqueous electrolyte battery electrode, and a nonaqueous electrolyte battery using the binder composition.

In recent years, mobile terminals such as mobile phones, notebook computers, pad-type information terminal devices have been widely used. Lithium ion secondary batteries are frequently used as secondary batteries used for the power sources of these portable terminals. Since portable terminals are required to have more comfortable portability, miniaturization, thinning, weight reduction, and high performance have rapidly progressed, and have come to be used in various places. This trend continues today, and batteries used in mobile terminals are further required to be smaller, thinner, lighter, and higher in performance.

A non-aqueous electrolyte battery such as a lithium ion secondary battery has a positive electrode and a negative electrode installed via a separator, and LiPF ₆ , LiBF ₄ LiTFSI (lithium (bistrifluoromethylsulfonylimide)), LiFSI (lithium (bisfluorosulfonylimide). )) And a lithium salt dissolved in an organic liquid such as ethylene carbonate in a container.

The above negative electrode and positive electrode are usually for electrodes obtained by dissolving or dispersing a binder and a thickener in water or a solvent and mixing this with an active material and, if necessary, a conductive additive (conductivity imparting agent). A slurry (hereinafter sometimes simply referred to as a slurry) is applied to a current collector, and water or a solvent is dried to form a mixed layer so as to be bound. More specifically, for example, for the negative electrode, a carbonaceous material capable of occluding and releasing lithium ions, which is an active material, and, if necessary, acetylene black, a conductive auxiliary agent, are secondary to a current collector such as copper. They are bound together by a binder for battery electrodes. On the other hand, for the positive electrode, LiCoO ₂ that is an active material and, if necessary, a conductive aid similar to that of the negative electrode are bound to a current collector such as aluminum using a secondary battery electrode binder. Is.

In recent years, from the viewpoint of reducing environmental burden and the simplicity of manufacturing equipment, interest from a slurry using a solvent to a slurry using water has increased, and in particular, there has been a rapid shift in the negative electrode.

The most industrially used binder for aqueous media is a system in which carboxymethylcellulose sodium salt (CMC-Na) is added as a thickener to a diene rubber such as styrene-butadiene rubber (SBR). (For example, patent document 1). However, diene rubbers such as styrene-butadiene rubber have low adhesion to metal collectors such as copper, and there is a problem that the amount used cannot be reduced to increase the adhesion between the collector and the electrode material. . In addition, there is a problem that the capacity maintenance rate is low due to weakness against heat generated during charging and discharging. Furthermore, since it is a two-component system, it has problems in manufacturing such as low storage stability and complicated slurry preparation process.

In order to solve the problem of the SBR / CMC-Na addition system, an acrylic binder such as polyacrylic acid (for example, Patent Document 2) or a polyamide / imide binder (for example, Patent Document 3) has been developed. .

Acrylic binders are excellent in that they exhibit high adhesion and have low swellability to electrolytes. On the other hand, there is a problem that the electric resistance is high, the flexibility is poor, and the electrode is easily broken. As for flexibility, for example, Patent Document 4 discloses that a nitrile group is introduced and improved, but the electrical resistance still tends to be high.

In addition, polyamide / imide binders also exhibit high adhesion, and are particularly excellent in electrical, thermal stability, and mechanical strength. The problem is that, like acrylic binders, the electrical resistance is high, the flexibility is poor and the electrode is easily cracked, but the mechanical strength is utilized to accompany the insertion and desorption of lithium ions during charging and discharging. An example of supplementing flexibility by using a metal oxide having a large expansion and contraction of an electrode as a negative electrode active material has been reported (for example, Patent Document 5). However, the combination of polyamide / imide binder and metal oxide has not fully solved the problems of high resistance and poor flexibility, and the polyamide / imide binder is expensive. There is also.

Recently, demands for extending the usage time of mobile devices and shortening the charging time have increased. In particular, the battery capacity (low resistance, high efficiency), life (cycle characteristics), charging speed (rate characteristics) Improvement is an urgent need.

In a non-aqueous electrolyte battery, since the battery capacity is affected by the amount of active material, it is effective to suppress the amount of binder and thickener in order to increase the active material in a limited space of the battery. Moreover, since the rate characteristics are also affected by the ease of electron movement, it is effective to suppress the amount of binder and thickener that are non-conductive and prevent electron movement. However, if the amount of the binder and the thickener is reduced, the binding property between the collector electrode and the electrode material and the active material in the electrode is lowered, and the durability (battery life) for long-term use is significantly reduced. However, the electrode becomes brittle. Thus, it has been difficult to improve the battery characteristics such as the battery capacity, particularly to reduce the resistance while maintaining the binding property between the collecting electrode and the electrode material and maintaining the toughness as an electrode.

The present invention has been made in view of the above-mentioned problems, and the battery characteristics in the nonaqueous electrolyte battery are obtained without impairing the function as the binder, that is, the binding property between the active materials and the collector electrode and the toughness as the electrode. The purpose is to improve (high efficiency).

Japanese Patent Laid-Open No. 2014-13693 JP 2002-260667 A JP 2001-68115 A JP 2003-282061 A JP2015-65164A

As a result of diligent research to solve the above problems, the present inventors have found that the above object can be achieved by using a binder composition for a nonaqueous electrolyte battery having the following constitution, and further studies are made based on this finding. The present invention was completed by overlapping.

That is, the binder composition for a nonaqueous electrolyte battery according to one aspect of the present invention (hereinafter also simply referred to as a binder composition) includes (A) polyvinyl alcohol, and (B) vinyl alcohol and an ethylenically unsaturated carboxylic acid. And at least one selected from a copolymer of the above and a neutralized salt thereof.

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 of the present embodiment (hereinafter also simply referred to as a binder composition) includes the following (A) and (B):
(A) polyvinyl alcohol,
(B) At least one selected from a copolymer of vinyl alcohol and an ethylenically unsaturated carboxylic acid and a neutralized salt thereof.

According to the above configuration, a binder composition for a nonaqueous electrolyte battery having binding properties and toughness can be obtained, and further, the battery characteristics (high efficiency) of the nonaqueous electrolyte battery can be improved using the binder composition. can do.

The content of polyvinyl alcohol as component (A) in the binder composition of the present embodiment is not particularly limited, but is preferably 50% by weight or less, and 40% by weight or less. Is more preferable, and it is still more preferable that it is 30 weight% or less. Further, the lower limit of the content of the polyvinyl alcohol is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and further preferably 1% by weight or more. When the content of the component (A) exceeds 50% by weight, the electrical resistance may increase and high charge / discharge efficiency may not be obtained. When the content is less than 1% by weight, the slurry stability may deteriorate. .

By containing polyvinyl alcohol as the component (A), it is expected that the adhesiveness is improved by increasing the cohesiveness of the binder due to the carboxyl group and the affinity with the collector electrode. Moreover, by mixing different polymers, the molecular weight distribution is apparently broadened, and the crystallinity of the polymer is further lowered, so that an effect of improving flexibility can be expected. In addition, an effect of improving the slurry stability can be expected by suppressing aggregation of a single polymer by intermolecular interaction with a different polymer.

In this embodiment, the saponification degree of polyvinyl alcohol is not particularly limited, and is usually 50 mol% or more, more preferably 80 mol% or more, and further preferably 95 mol% or more. When the degree of saponification is low, it is not preferable because the alkali metal contained in the binder composition may be hydrolyzed and stability may not be determined.

In the present embodiment, the ethylenically unsaturated carboxylic acid constituting the component (B) is, for example, ethylenically unsaturated monocarboxylic acid such as acrylic acid, methacrylic acid, methyl ester of methacrylic acid, ethyl ester, crotonic acid, And ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid and maleic acid. Among these, acrylic acid, methacrylic acid, and maleic acid are particularly preferable from the viewpoints of availability, polysynthesis, and product stability. One of these ethylenically unsaturated carboxylic acid esters may be used alone, or two or more thereof may be used in combination.

The content ratio of vinyl alcohol and ethylenically unsaturated carboxylic acid in the copolymer of component (B) of this embodiment is preferably in the range of 100/1 to 1/100 in terms of molar ratio. This is because the advantages of hydrophilicity, water solubility, and affinity for metals and ions as a high molecular weight substance that dissolves in water can be obtained. When there is too little ethylenically unsaturated carboxylic acid, adhesiveness and a softness | flexibility will fall, and when too much, thermal / electrical stability will fall.

In at least one selected from (B) vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer and neutralized salt thereof in the copolymer of this embodiment, the copolymerization form is not particularly limited, and random copolymerization , Alternating copolymerization, block copolymerization, graft copolymerization and the like. In particular, in order to obtain high adhesion, block copolymerization and graft copolymerization in which vinyl alcohol is regularly arranged are preferable. Moreover, from the viewpoint of achieving both adhesiveness and flexibility, a graft copolymer is more preferable.

The method for producing the copolymer of the present embodiment is not particularly limited, and any polymerization initiation method such as anionic polymerization, cationic polymerization, or radical polymerization may be used. The polymer production method may be solution polymerization. Any method such as bulk polymerization, suspension polymerization, dispersion polymerization, or emulsion polymerization may be used.

In at least one selected from vinyl alcohol, an ethylenically unsaturated carboxylic acid copolymer and a neutralized salt thereof as component (B) of this embodiment, the amount of the ethylenically unsaturated carboxylic acid modification is 0.1 It is preferably about ˜60 mol%. Thereby, there exists an advantage that toughness and low resistance can be provided. A more preferable modification amount of the ethylenically unsaturated carboxylic acid is about 1 to 40 mol%. The amount of ethylenically unsaturated carboxylic acid modification in this embodiment can be quantified by, for example, nuclear magnetic resonance spectroscopy (NMR).

Further, from the viewpoint of heat resistance, the amount of modification with the ethylenically unsaturated carboxylic acid is preferably less than 20 mol%, and more preferably less than 15 mol%. From the viewpoint of improving low resistance, it is also a preferred embodiment that the amount of modification with the ethylenically unsaturated carboxylic acid is 11 mol% or more.

The average molecular weight of the copolymer of the present embodiment is preferably a number average molecular weight of 5,000 to 250,000. When the number average molecular weight of the copolymer is less than 5,000, the mechanical strength of the binder may be lowered. The number average molecular weight is more preferably 10,000 or more, and further preferably 15,000 or more. On the other hand, when the number average molecular weight of the copolymer exceeds 250,000, the viscosity stability of the slurry composition for non-aqueous electrolyte batteries is reduced, and the handling properties are insufficient, such as causing the aggregation of the slurry. There is a fear. The number average molecular weight is more preferably 200,000 or less, and further preferably 150,000 or less. The number average molecular weight of the copolymer in the present invention means a value measured by a gel permeation chromatography (GPC) method using polyethylene oxide and polyethylene glycol as standard substances and an aqueous column as a column.

In this embodiment, the neutralized salt of a copolymer is a neutralized product by reacting an active hydrogen of carbonyl acid generated from an ethylenically unsaturated carboxylic acid with a basic substance to form a salt. It is preferable. In the (B) vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer and / or neutralized salt thereof used in the present embodiment, a monovalent metal is used as the basic substance from the viewpoint of binding properties as a binder. It is preferable to use a basic substance containing and / or ammonia.

Examples of basic substances containing monovalent metals that can be used in the present embodiment include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; alkali metals such as sodium carbonate and potassium carbonate. Carbonates of alkali metals such as sodium acetate and potassium acetate; phosphates of alkali metals such as trisodium phosphate, and the like. Among these, ammonia, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferable. In particular, it is preferable to use ammonia or lithium hydroxide as a binder for a lithium ion secondary battery. The basic substance containing monovalent metal and / or ammonia may be used alone or in combination of two or more. In addition, a neutralized product may be prepared by using a basic substance containing an alkali metal hydroxide such as sodium hydroxide as long as the battery performance is not adversely affected.

The degree of neutralization is not particularly limited, but when used as a binder, considering the reactivity with the electrolytic solution, it is usually 0. It is preferably in the range of 1 to 1 equivalent, and more preferably neutralized in the range of 0.3 to 1 equivalent. Such a neutralization degree has the advantage of low acidity and suppression of electrolyte decomposition.

In this embodiment, the determination method of the degree of neutralization can use methods such as titration with a base, infrared spectrum, NMR spectrum, etc. In order to measure the neutralization point simply and accurately, titration with a base is used. Preferably it is done. The specific titration method is not particularly limited, but it can be dissolved in water with little impurities such as ion-exchanged water, and a basic substance such as lithium hydroxide, sodium hydroxide, potassium hydroxide, It can be carried out by neutralization. The indicator for the neutralization point is not particularly limited, but an indicator such as phenolphthalein whose pH is indicated by a base can be used.

In the present embodiment, the usage amount of the basic substance containing monovalent metal and / or ammonia is not particularly limited and is appropriately selected depending on the purpose of use, etc., but is usually an ethylenically unsaturated carboxylic acid unit. The amount is preferably 0.1 to 1 equivalent to the amount. The amount of the basic substance containing a monovalent metal is preferably 0.3 to 1.0 equivalent, more preferably 0.4 to 1.0, based on the maleic acid unit in the maleic acid copolymer. When the amount is equivalent, a water-soluble copolymer salt with little alkali residue can be obtained.

In the present embodiment, the reaction of (B) vinyl alcohol with an ethylenically unsaturated carboxylic acid copolymer and / or a neutralized salt thereof can be carried out according to a conventional method. The method obtained as an aqueous solution is simple and preferable.

In the binder composition of the present embodiment, the content of vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer and / or neutralized salt thereof as component (B) is not particularly limited, It is preferably 99.9% by weight or less, more preferably 99.5% by weight or less, and still more preferably 99% by weight or less. The lower limit of the content is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and more preferably 80% by weight or more. Particularly preferred. When the content of the component (B) exceeds 99.9% by weight, the slurry stability may be deteriorated. When the content is less than 50% by weight, the electrical resistance increases and high charge / discharge efficiency cannot be obtained. There is.

In the present embodiment, the composition ratio of the component (A) and the component (B) is preferably about 0.1: 99.9 to 50:50 in terms of solid content weight ratio. More preferably, it is about 1:99 to 40:60. Further, from the viewpoint of obtaining low resistance, the composition ratio of the component (A) and the component (B) is preferably 1:99 to 30:70, and is about 1:99 to 20:80. More preferably.

The binder composition of this embodiment is usually used as a binder aqueous solution for a non-aqueous electrolyte battery comprising the above-described binder composition and water.

The binder composition for a nonaqueous electrolyte battery of the present embodiment is usually a slurry composition for a nonaqueous electrolyte battery (hereinafter simply referred to as a slurry composition), which further contains an active material and water in addition to the binder composition described above. (Also referred to as). That is, the slurry composition of this embodiment contains the binder composition of this embodiment mentioned above, an active material, and water.

Further, in the present embodiment, the electrode for a nonaqueous electrolyte battery is characterized in that a mixed layer containing at least the binder composition of the present embodiment and an active material is bound to a current collector. This electrode can be formed by applying the slurry composition described above to a current collector and then removing the solvent by a method such as drying. If necessary, a thickener, a conductive aid and the like can be added to the mixed layer.

In the non-aqueous electrolyte battery slurry composition, when the weight of the active material is 100, the amount of the binder composition used is usually preferably 0.1 to 15% by weight, more preferably 0.00. 5 to 10% by weight, more preferably 1 to 8% by weight. If the amount of the binder composition is excessively small, the viscosity of the slurry is too low and the thickness of the mixed layer may be reduced. If the amount of the binder composition is excessively large, the discharge capacity may be reduced.

On the other hand, the amount of water in the slurry composition is usually preferably 30 to 150% by weight, more preferably 70 to 120% by weight, where the weight of the active material is 100.

As the solvent in the slurry composition of the present embodiment, in addition to the above water, for example, alcohols such as methanol, ethanol, propanol and 2-propanol, cyclic ethers such as tetrahydrofuran and 1,4-dioxane, N, N— Amides such as dimethylformamide and N, N-dimethylacetamide, cyclic amides such as N-methylpyrrolidone and N-ethylpyrrolidone, and sulfoxides such as dimethylsulfoxide can also be used. In these, use of water is preferable from a viewpoint of safety.

Further, in addition to water as the solvent of the slurry composition of the present embodiment, the following organic solvent may be used in combination within a range of preferably 20% by weight or less of the entire solvent. Such an organic solvent preferably has a boiling point at normal pressure of 100 ° C. or higher and 300 ° C. or lower, for example, hydrocarbons such as n-dodecane; alcohols such as 2-ethyl-1-hexanol and 1-nonanol. Esters such as γ-butyrolactone and methyl lactate; amides such as N-methylpyrrolidone, N, N-dimethylacetamide and dimethylformamide; and organic dispersion media such as sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane.

When the slurry composition of the present embodiment is used for a negative electrode, examples of the negative electrode active material added to the slurry composition include amorphous carbon, graphite, natural graphite, mesocarbon microbeads (MCMB), pitch-based carbon fibers, and the like. polyacene conductive polymer such as; carbonaceous material SiOx, SnOx, composite metal oxides and other metal oxides or lithium metal represented by LiTiOx, lithium metal such as lithium _alloy; TiS 2, LiTiS ₂ etc. Examples of the metal compound are as follows.

When the slurry composition of the present embodiment is used for a positive electrode, examples of the positive electrode active material added to the slurry composition include lithium iron phosphate (LiFePO ₄ ), lithium manganese phosphate (LiMnPO ₄ ), and phosphoric acid. Cobalt lithium (LiCoPO ₄ ), iron pyrophosphate (Li ₂ FeP ₂ O ₇ ), lithium cobalt oxide composite oxide (LiCoO ₂ ), spinel type lithium manganate composite oxide (LiMn ₂ O ₄ ), lithium manganate composite oxidation (LiMnO ₂ ), lithium nickelate composite oxide (LiNiO ₂ ), lithium niobate composite oxide (LiNbO ₂ ), lithium ferrate composite oxide (LiFeO ₂ ), lithium magnesium oxide composite oxide (LiMgO ₂ ), lithium composite oxide of calcium acid (LiCaO _2), cuprate lithium Beam composite oxide (LiCuO _2), zinc lithium composite oxide (LiZnO _2), lithium composite oxide molybdate (LiMoO _2), lithium tantalate complex oxide (LiTaO _2), tungstic acid lithium composite oxide (LiWO ₂ ), lithium-nickel-cobalt-aluminum composite oxide (LiNi _0.8 Co _0.15 Al _0.05 O ₂ ), lithium-nickel-cobalt-manganese composite oxide (LiNi _0.33 Co _0.33 Mn _0.33 O ₂ ), Li-rich nickel-cobalt-manganese composite oxide (LixNiACoBMnCO ₂ solid solution), manganese oxide nickel (LiNi _0.5 Mn _1.5 O ₄ ), manganese oxide (MnO ₂ ), vanadium-based oxidation Products, sulfur oxides, silicate oxides, etc. Indicated.

In this embodiment, a thickener can be further added to the slurry composition as necessary. The thickener that can be added is not particularly limited, and various alcohols, unsaturated carboxylic acids and modified products thereof, α-olefin-maleic acids and modified products thereof, celluloses, starches and other polysaccharides can be used. Can be used.

The amount of the thickener used as necessary in the slurry composition is preferably about 0.1 to 4% by weight, more preferably 0.3 to 4% when the weight of the active material is 100. It is 3% by weight, more preferably 0.5 to 2% by weight. If the thickener is too small, the viscosity of the secondary battery negative electrode slurry may be too low and the thickness of the mixed layer may be reduced. Conversely, if the thickener is excessively large, the discharge capacity may be reduced. .

Further, examples of the conductive auxiliary compounded in the slurry composition as necessary include metal powder, conductive polymer, acetylene black, and the like. The amount of the conductive aid used is usually preferably 0.1 to 10% by weight, more preferably 0.8 to 7% by weight when the weight of the active material is 100.

As described above, in the present embodiment, the electrode for a nonaqueous electrolyte battery is characterized in that a mixed layer containing at least the binder composition of the present embodiment and an active material is bound to a current collector. The current collector used for the nonaqueous electrolyte battery negative electrode of the present embodiment is not particularly limited as long as it is made of a conductive material. For example, iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold Metal materials such as platinum can be used. One of these may be used alone, or two or more of these may be used in combination at any ratio.

In particular, when copper is used as the negative electrode current collector, the effect of the nonaqueous electrolyte battery negative electrode slurry of the present invention is most apparent. This is because the negative electrode having high affinity between the binder composition of the present embodiment and the copper foil can be produced. The shape of the current collector is not particularly limited, but usually it is preferably a sheet having a thickness of about 0.001 to 0.5 mm.

Furthermore, when aluminum is used as the positive electrode current collector, the effect of the non-aqueous electrolyte battery negative electrode slurry of the present invention is most apparent. This is because the negative electrode having high affinity with the binder composition of the present embodiment and a certain non-nium foil can be produced. The shape of the current collector is not particularly limited, but usually it is preferably a sheet having a thickness of about 0.001 to 0.5 mm.

The method for applying the slurry to the current collector is not particularly limited. Examples thereof include a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a dipping method, and a brush coating method. The amount to be applied is not particularly limited, but the thickness of the mixed layer containing the active material, conductive additive, binder and thickener formed after removing the solvent or dispersion medium by a method such as drying is preferably 0.005 to An amount of 5 mm, more preferably 0.01 to 2 mm is common.

The method for drying a solvent such as water contained in the slurry composition is not particularly limited, and examples thereof include aeration drying with hot air, hot air, and low-humidity air; vacuum drying; drying with infrared rays, far infrared rays, electron beams, and the like. . The drying conditions are preferably adjusted so that the solvent can be removed as soon as possible while the active material layer is cracked by stress concentration or the active material layer does not peel from the current collector. Furthermore, 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.

Furthermore, the present invention also includes a nonaqueous electrolyte battery having the above electrode. The nonaqueous electrolyte battery usually includes a negative electrode, a positive electrode, and an electrolytic solution.

When using the binder composition of this embodiment for a positive electrode, the negative electrode normally used for nonaqueous electrolyte batteries, such as a lithium ion secondary battery, is used without a restriction | limiting especially. For example, graphite, hard carbon, Si-based oxide, etc. are used as the negative electrode active material. Also, the negative electrode active material is composed of the above-mentioned conductive additive and a binder such as SBR, NBR, acrylic rubber, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinylidene fluoride, and the boiling point at 100 ° C. A negative electrode slurry prepared by mixing in a solvent at a temperature of 0 ° C. or lower can be applied to a negative electrode current collector such as a copper foil, and the solvent can be dried to obtain a negative electrode.

When using the binder composition of this embodiment for a negative electrode, the positive electrode normally used for nonaqueous electrolyte batteries, such as a lithium ion secondary battery, is especially used for a positive electrode without a restriction | limiting. For example, as the positive electrode active material, TiS ₂ , TiS ₃ , amorphous MoS ₃ , Cu ₂ V ₂ O ₃ , amorphous V ₂ O—P ₂ O ₅ , MoO ₃ , V ₂ O ₅ , V ₆ O Transition metal oxides such as ₁₃ and lithium-containing composite metal oxides such as LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , and LiMn ₂ O ₄ are used. In addition, the positive electrode active material is composed of the above-described conductive additive and a binder such as SBR, NBR, acrylic rubber, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinylidene fluoride, and the boiling point at 100 ° C. The positive electrode slurry prepared by mixing in a solvent at a temperature of 0 ° C. or lower can be applied to a positive electrode current collector such as aluminum and the solvent can be dried to obtain a positive electrode.

Moreover, the electrode containing the binder composition of this embodiment can also be used for both the positive electrode and the negative electrode.

In the nonaqueous electrolyte battery of this embodiment, an electrolytic solution in which an electrolyte is dissolved in a solvent can be used. The electrolyte solution may be liquid or gel as long as it is used for a non-aqueous electrolyte battery such as a normal lithium ion secondary battery, and functions as a battery depending on the type of the negative electrode active material and the positive electrode active material. What is necessary is just to select suitably. Specific electrolytes, for example, also known lithium salt is any conventionally _{_{_{available, LiClO 4, LiBF 6, LiPF}}} 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10 , LiAlCl ₄ , 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 And lower aliphatic lithium carboxylates.

A solvent (electrolyte solvent) for dissolving such an electrolyte is not particularly limited. Specific examples include carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, and diethyl carbonate; lactones such as γ-butyllactone; trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, and 2-ethoxyethane. Ethers such as tetrahydrofuran, 2-methyltetrahydrofuran; sulfoxides such as dimethyl sulfoxide; oxolanes such as 1,3-dioxolane, 4-methyl-1,3-dioxolane; nitrogen-containing compounds such as acetonitrile and nitromethane; formic acid Organic acid esters such as methyl, methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; inorganic acid esters such as triethyl phosphate, dimethyl carbonate and diethyl carbonate Terigres; diglymes; triglymes; sulfolanes; oxazolidinones such as 3-methyl-2-oxazolidinone; sultones such as 1,3-propane sultone, 1,4-butane sultone, naphtha sultone, etc. Alternatively, two or more kinds can be mixed and used. When a gel electrolyte is used, a nitrile polymer, an acrylic polymer, a fluorine polymer, an alkylene oxide polymer, or the like can be added as a gelling agent.

Although there is no limitation in particular as a method of manufacturing the nonaqueous electrolyte battery of this embodiment, For example, the following manufacturing method is illustrated. That is, the negative electrode and the positive electrode are overlapped with each other via a separator such as a polypropylene porous membrane, wound or folded according to the shape of the battery, put into a battery container, injected with an electrolyte, and sealed. The shape of the battery may be any known coin type, button type, sheet type, cylindrical type, square type, flat type, and the like.

The nonaqueous electrolyte battery of this embodiment is a battery that achieves both improved adhesion and improved battery characteristics, and is useful for various applications. For example, the battery is very useful as a battery used in a portable terminal that is required to be small, thin, light, and have high performance.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

The binder composition for a non-aqueous electrolyte battery according to one aspect of the present invention is selected from (A) polyvinyl alcohol, and (B) a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof. Including at least one of the following.

With such a configuration, it is considered that the battery characteristics can be improved without impairing the binding property between the active materials and the collector electrode and the toughness as an electrode.

In the binder composition, at least one selected from (B) a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof is copolymerized in the form of block copolymerization. It is preferable. Thereby, it is considered that higher adhesiveness can be obtained.

Further, in the binder composition, at least one selected from (B) a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof is copolymerized in the form of graft copolymerization. It is preferable. Thereby, it is considered that both adhesiveness and flexibility can be achieved.

In the binder composition, at least one selected from (B) a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof has an ethylenically unsaturated carboxylic acid modification amount of 0. It is preferably 1 to 60 mol%. Thereby, it is considered that toughness and low resistance can be imparted.

The content of the component (B) in the binder composition is preferably 50.0 to 99.9% by weight. Thereby, it is considered that slurry stability and higher charge / discharge efficiency can be obtained.

A binder aqueous solution for a nonaqueous electrolyte battery according to still another aspect of the present invention is characterized by containing the binder composition and water.

A slurry composition for a non-aqueous electrolyte battery according to still another aspect of the present invention is characterized by containing the binder composition, an active material, and water.

The electrode for a non-aqueous electrolyte battery according to still another aspect of the present invention is characterized in that a mixed layer containing the binder composition and the active material is bound to a current collector.

A nonaqueous electrolyte battery according to still another aspect of the present invention has the above electrode for a nonaqueous electrolyte battery.

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

Example 1
<Synthesis of vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer>
100 g of commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., 28-98s) was irradiated with an electron beam (30 kGy). Next, 33.4 g of acrylic acid and 466.6 g of methanol were charged into a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, and a particle addition port, and the inside of the system was purged with nitrogen for 30 minutes while bubbling nitrogen. . 100 g of polyvinyl alcohol irradiated with an electron beam was added thereto, and the mixture was stirred and heated and refluxed for 300 minutes in a state where the particles were dispersed in the solution to carry out graft polymerization. Thereafter, the particles were collected by filtration and vacuum-dried at 40 ° C. overnight to obtain the desired copolymer. The amount of ethylenic unsaturated carboxylic acid modification of the obtained copolymer was 6.8 mol%.

<Preparation of neutralized salt of vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer>
Lithium hydroxide was added in an amount of 0.5 equivalent to the carboxylic acid unit in the polymer to 100 g of the vinyl alcohol and acrylic acid copolymer 10% by weight aqueous solution obtained above, and heated and stirred at 80 ° C. for 2 hours. Cooled to room temperature.

<Preparation of aqueous binder solution>
A 10% by weight aqueous solution (B-1) of a neutralized salt of vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer obtained above was added to commercially available polyvinyl alcohol (Kuraray Co., Ltd., 28-98s, saponification degree: 98) (A-1) was added as a solid content in a weight ratio of (A-1) :( B-1) = 10: 90 to prepare a binder aqueous solution.

<Measurement of melting point of neutralized salt of vinyl alcohol and ethylenically unsaturated carboxylic acid copolymer>
Using a solid obtained by drying 1 g of the aqueous binder solution at 105 ° C. for 1 hour with a hot air dryer, differential scanning calorimetry was performed using a thermal analyzer (manufactured by Yamato Kagaku Co., Ltd.). The measurement was performed at a measurement temperature range of 50 ° C. to 1000 ° C. and a heating rate of 10 ° C./min. The results are shown in Table 1 below.

<Preparation of slurry>
The electrode slurry was prepared by adding 3 parts by weight of a 10% by weight aqueous solution of the binder composition as a solid content to 96 parts by weight of natural graphite (manufactured by DMGS, BYD) as an active material for a negative electrode, 1 part by weight of Super-P (manufactured by Timcal Co.) as a solid component was put into a special container and kneaded using a planetary stirrer (ARE-250, manufactured by Sinky) to prepare an electrode coating slurry. . The composition ratio of the active material and the binder in the slurry is, as a solid content, graphite powder: conductive aid: binder composition = 96: 1: 3 (weight ratio).

<Slurry stability>
In order to confirm the stability of the obtained slurry, the state of particle sedimentation immediately after slurry adjustment (within 30 minutes) was visually confirmed. The slurry in which sedimentation did not occur was indicated as ◯, and the slurry in which sedimentation occurred was indicated as x. The results are shown in Table 1 below.

<Preparation of negative electrode for battery>
The obtained slurry was coated on a current collector copper foil (CST8G, manufactured by Fukuda Metal Foil Co., Ltd.) using a bar coater (T101, manufactured by Matsuo Sangyo), and heated at 80 ° C. for 30 minutes. Then, after the primary drying, rolling was performed using a roll press (made by Hosen). Then, after punching out as a battery electrode (φ14 mm), a coin battery electrode was produced by secondary drying under reduced pressure conditions at 140 ° C. for 3 hours.

<Preparation of peel strength and toughness test electrode>
The obtained slurry was coated on a current collector copper foil (CST8G, manufactured by Fukuda Metal Foil Co., Ltd.) using a bar coater (T101, manufactured by Matsuo Sangyo), and heated at 80 ° C. for 30 minutes. Then, after the primary drying, a test was performed using an electrode (film thickness: about 40 μm) that had been rolled using a roll press (made by Hosen).

<Electrode toughness test>
The evaluation of the toughness of the electrode was performed by visually checking whether or not cracking occurred when the electrode was bent using the toughness test electrode having a width of 10 mm. An electrode in which no crack was generated was indicated as ◯, and an electrode in which the crack was generated was indicated as x. The results are shown in Table 1 below.

<Measurement of peel strength of electrode>
The strength when the peel strength test electrode was peeled from the copper foil as the collecting electrode was measured. The peel strength was measured at 180 ° peel strength using a 50N load cell (manufactured by Imada Co., Ltd.). The slurry-coated surface of the battery-coated electrode obtained above and a stainless steel plate were bonded together using a double-sided tape (double-faced tape made by Nichiban), and the 180 ° peel strength (peel width 10 mm, peel rate 100 mm / min) was measured. did. The results are shown in Table 1 below.

<Production of battery>
The negative electrode for a battery obtained above was transferred to a glove box (manufactured by Miwa Seisakusho) under an argon gas atmosphere. A metal lithium foil (thickness 0.2 mm, φ16 mm) was used for the positive electrode. In addition, a polypropylene separator (Celgard # 2400, manufactured by Polypore) was used as a separator, and the electrolyte was ethylene carbonate (EC) of lithium hexafluorophosphate (LiPF ₆ ) and vinylene carbonate (EMC) to vinylene carbonate (EMC). VC) was added using a mixed solvent system (1M-LiPF ₆ , EC / EMC = 3/7 vol%, VC 2 wt%) to prepare a coin battery (2032 type).

<Charge / discharge characteristics test>
The produced coin battery was subjected to a charge / discharge test using a commercially available charge / discharge tester (TOSCAT3100, manufactured by Toyo System). The coin battery is placed in a constant temperature bath at 25 ° C., and charging is performed with a constant current of 0.1 C (about 0.5 mA / cm ² ) with respect to the amount of active material until the voltage reaches 0 V with respect to the lithium potential. On the other hand, the constant voltage charge of 0V was implemented to the electric current of 0.02 mA. The capacity at this time was defined as a charging capacity (mAh / g). Next, a constant current discharge of 0.1 C (about 0.5 mA / cm ² ) was performed up to 1.5 V with respect to the lithium potential, and the capacity at this time was defined as a discharge capacity (mAh / g). The difference between the initial discharge capacity and the charge capacity was taken as the irreversible capacity, and the percentage of the discharge capacity / charge capacity was taken as the charge / discharge efficiency. The results are shown in Table 1 below.

(Example 2)
Vinyl alcohol and an ethylenically unsaturated carboxylic acid copolymer were synthesized in the same manner as in Example 1. Further, 1.0 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-2) of the copolymer. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-2) = 10: 90. Adjustments were made.

A slurry for a non-aqueous electrolyte battery was prepared in the same manner as in Example 1 above, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Example 3)
The target copolymer was synthesized in the same manner as in Example 1 except that 100 g of acrylic acid and 400 g of methanol were added. The amount of ethylenically unsaturated carboxylic acid modification of the obtained copolymer was 26.2 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-3) of the copolymer. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content in a weight ratio of (A-3) :( B-3) = 7: 93. Adjustments were made.

Example 4
100 g of commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., 22-88s) was irradiated with an electron beam (30 kGy). Next, 33.5 g of acrylic acid and 466.5 g of methanol were charged into a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, and a particle addition port, and the system was purged with nitrogen for 30 minutes while bubbling nitrogen. . 100 g of polyvinyl alcohol irradiated with an electron beam was added thereto, and the mixture was stirred and heated and refluxed for 300 minutes in a state where the particles were dispersed in the solution to carry out graft polymerization. Thereafter, the particles were collected by filtration and vacuum-dried at 40 ° C. overnight to obtain the desired copolymer. The amount of ethylenic unsaturated carboxylic acid modification of the obtained copolymer was 7.1 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-4) of the copolymer. Thereafter, commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., 22-88s, saponification degree: 88) (A-2) as a solid content, (A-2) :( B-4) = 10: 90 in weight ratio It added so that binder aqueous solution might be adjusted.

(Example 5)
100 g of commercially available polyvinyl alcohol (Elvanol 71-30, manufactured by Kuraray Co., Ltd.) was irradiated with an electron beam (30 kGy). Next, 25 g of methacrylic acid and 475 g of methanol were charged into a reactor equipped with a stirrer, a reflux condenser, a nitrogen introduction tube and a particle addition port, and the system was purged with nitrogen for 30 minutes while bubbling nitrogen. 100 g of polyvinyl alcohol irradiated with an electron beam was added thereto, and the mixture was stirred and heated and refluxed for 300 minutes in a state where the particles were dispersed in the solution to carry out graft polymerization. Thereafter, the particles were collected by filtration and vacuum-dried at 40 ° C. overnight to obtain the desired copolymer. The amount of ethylenically unsaturated carboxylic acid modification of the obtained copolymer was 7.0 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-5) of the copolymer. Thereafter, commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., Elvanol 71-30, saponification degree: 99) (A-3) as a solid content, (A-3) :( B-5) = 12: 88 in weight ratio It added so that it might become, and adjustment of the binder aqueous solution was performed.

(Example 6)
The target copolymer was synthesized in the same manner as in Example 5 except that 100 g of methacrylic acid and 400 g of methanol were added. The amount of ethylenic unsaturated carboxylic acid modification of the obtained copolymer was 34.0 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-6) of the copolymer. Thereafter, commercially available polyvinyl alcohol (A-3) as in Example 5 was added as a solid content so that the weight ratio was (A-3) :( B-6) = 5: 95, and the aqueous binder solution Adjustments were made.

(Example 7)
A reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, and an initiator addition port was charged with 370 g of water and 100 g of commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., M115), and heated at 95 ° C. with stirring. After the polyvinyl alcohol was dissolved, it was cooled to room temperature. 0.5N (N) sulfuric acid was added to the aqueous solution to adjust the pH to 3.0. To this was added 9.9 g of acrylic acid with stirring, and then the mixture was heated to 70 ° C. while bubbling nitrogen into the aqueous solution, and further purged with nitrogen by bubbling nitrogen for 30 minutes while maintaining 70 ° C. After nitrogen substitution, 80.7 g of an aqueous potassium persulfate solution (concentration: 2.5% by weight) was added dropwise to the aqueous solution over 1.5 hours. After addition of the entire amount, the temperature was raised to 75 ° C., and the mixture was further stirred for 1 hour, and then cooled to room temperature. The obtained aqueous solution was poured onto a PET film and dried in hot air at 80 ° C. for 30 minutes to produce a film. The film was frozen with liquid nitrogen, pulverized using a centrifugal pulverizer, and further vacuum dried at 40 ° C. overnight to obtain the desired copolymer. The amount of ethylenic unsaturated carboxylic acid modification of the obtained copolymer was 6.0 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-7) of the copolymer. Thereafter, commercially available polyvinyl alcohol (A-1) similar to that in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-7) = 10: 90. Adjustments were made.

(Example 8)
Vinyl alcohol and an ethylenically unsaturated carboxylic acid copolymer were synthesized in the same manner as in Example 7. Further, 1.0 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-8) of the copolymer. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-8) = 10: 90. Adjustments were made.

(Example 9) A vinyl alcohol and an ethylenically unsaturated carboxylic acid copolymer were prepared in the same manner as in Example 7 except that 20 g of acrylic acid and 150 g of a potassium persulfate aqueous solution (concentration: 2.5 wt%) were added. Synthesized. The amount of ethylenically unsaturated carboxylic acid modification of the obtained copolymer was 12.0 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-9) of the copolymer. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-9) = 10: 90. Adjustments were made.

A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Example 10) Vinyl alcohol and an ethylenically unsaturated carboxylic acid copolymer were synthesized in the same manner as in Example 9. Further, 0.3 equivalent of sodium hydroxide with respect to the carboxylic acid unit in the polymer and 0.2 equivalent of lithium hydroxide with respect to the carboxylic acid unit in the polymer were added, and the copolymer neutralized salt ( B-10) was prepared. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-10) = 10: 90. Adjustments were made.

(Example 11)

A reactor equipped with a stirrer, reflux condenser, argon inlet, and initiator addition port was charged with 640 g of vinyl acetate, 240.4 g of methanol, and 0.88 g of acrylic acid, and nitrogen was bubbled through the system for 30 minutes. Replaced. Separately, a methanol solution of acrylic acid (concentration: 20% by weight) was prepared as a comonomer sequential addition solution (hereinafter referred to as a delay solution), and argon was bubbled for 30 minutes. The temperature of the reactor was increased, and when the internal temperature reached 60 ° C., 0.15 g of 2,2′-azobisisobutyronitrile was added to initiate polymerization. During the progress of the polymerization reaction, the prepared delay solution was dropped into the system so that the monomer composition (molar ratio of vinyl acetate and acrylic acid) in the polymerization solution became constant. After polymerization at 60 ° C. for 210 minutes, the polymerization was stopped by cooling. Subsequently, unreacted monomers were removed while sometimes adding methanol under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate modified with acrylic acid. Next, 20.4 g of sodium hydroxide methanol solution (concentration 18.0 wt%) was added to 400 g of polyvinyl acetate methanol solution prepared by adding methanol to the methanol solution of polyvinyl acetate to a concentration of 25 wt%. 79.6 g of methanol was added and saponification was performed at 40 ° C. A gelled product was formed within a few minutes after the addition of the sodium hydroxide methanol solution. This was pulverized by a pulverizer and allowed to stand for 60 minutes at 40 ° C. to allow saponification to proceed. The obtained pulverized gel was repeatedly washed with methanol and then vacuum dried at 40 ° C. overnight to synthesize the desired copolymer. The amount of ethylenic unsaturated carboxylic acid modification of the obtained copolymer was 5.0 mol%. Further, 0.5 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-11) of the copolymer. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-11) = 10: 90. Adjustments were made.

(Example 12)

Using the same neutralized salt (B-11) as in Example 11 and using the same commercially available polyvinyl alcohol (A-1) as in Example 1 as the solid content, (A-1) :( B-11) ) = 40: 60, and the binder aqueous solution was adjusted.

(Example 13)

Vinyl alcohol and an ethylenically unsaturated carboxylic acid copolymer were synthesized in the same manner as in Example 11. Further, 1.0 equivalent of lithium hydroxide was added to the carboxylic acid unit in the polymer to prepare a neutralized salt (B-13) of the copolymer. Thereafter, the commercially available polyvinyl alcohol (A-1) used in Example 1 was added as a solid content so that the weight ratio was (A-1) :( B-13) = 10: 90. Adjustments were made.

(Comparative Example 1)

A 10% by weight aqueous solution of commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., 28-98s, saponification degree: 98) was prepared and used as a binder composition. A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Comparative Example 2)

A 10% by weight aqueous solution of commercially available polyvinyl alcohol (manufactured by Kuraray Co., Ltd., 22-88s, saponification degree: 88) was prepared and used as a binder composition. A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Comparative Example 3)
Using the same neutralized salt as in Example 1, a 10% by weight aqueous solution was prepared and used as a binder composition. A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Comparative Example 4)
Using the same neutralized salt as in Example 7, a 10 wt% aqueous solution was prepared and used as a binder composition. A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Comparative Example 5)
Using the same neutralized salt as in Example 11, a 10 wt% aqueous solution was prepared and used as a binder composition. A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Comparative Example 6)
A 10 wt% aqueous solution of polyacrylic acid (manufactured by Aldrich, molecular weight 250,000) was prepared and used as a binder composition. A slurry for a non-aqueous electrolyte battery was prepared by the same method as in Example 1, and the slurry stability was confirmed. Further, a battery coated negative electrode was prepared in the same manner as in Example 1 to obtain a coin battery, and a charge / discharge characteristic test was performed. Similarly, a toughness test and a peel strength coated electrode were prepared in the same manner as in Example 1, and a toughness test and a peel strength measurement were performed using the same. The results are shown in Table 1 below.

(Discussion)
In Examples 1 to 13 containing the component (A) and the component (B) of the present invention, it was shown that all of them achieved high charge / discharge efficiency of 92% or more due to the effect of the neutralized salt. It is assumed that the polymer salt coated the powdered active material to form an ionic conductive layer so that Li ions can easily move through the battery. Moreover, the improvement of slurry stability, toughness, and adhesiveness was seen by (A) component and (B) component, and 2 or more components coexisting. On the other hand, Comparative Examples 1 to 2 and 6 containing no neutralized salt had low charge / discharge efficiency (less than 92%), and the slurry stability, toughness and adhesion were all low.

As in the Examples, Comparative Examples 3 to 5 showed high charge / discharge efficiency, but on the other hand, since the slurry stability was low, it was difficult to form a uniform electrode. Compared with the Examples, slurry stability, toughness, adhesion Sex was not enough.

From the above, it has been clarified that by using the binder composition of the present invention, the battery characteristics of the nonaqueous electrolyte battery can be improved without impairing the binding property of the electrode binder and the toughness of the electrode.

This application is based on Japanese Patent Application No. 2017-50807 filed on Mar. 16, 2017, the contents of which are included in the present application.

In order to express the present invention, the present invention has been described appropriately and sufficiently through the embodiments with reference to specific examples and the like. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not limited to the scope of the claims. To be construed as inclusive.

The present invention has wide industrial applicability in the technical field related to non-aqueous electrolyte batteries such as lithium ion secondary batteries.

Claims

(A) polyvinyl alcohol, and
(B) at least one selected from a copolymer of vinyl alcohol and an ethylenically unsaturated carboxylic acid and a neutralized salt thereof,
A binder composition for a non-aqueous electrolyte battery, comprising:
The non-copolymer according to claim 1, wherein at least one selected from (B) a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof is copolymerized in the form of block copolymerization. Binder composition for water electrolyte battery.
The non-copolymer according to claim 1, wherein at least one selected from (B) a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof is copolymerized in the form of graft copolymerization. Binder composition for water electrolyte battery.
In (B) at least one selected from a copolymer of vinyl alcohol and ethylenically unsaturated carboxylic acid and a neutralized salt thereof, the amount of ethylenically unsaturated carboxylic acid modification is 0.1 to 60 mol%. The binder composition for a nonaqueous electrolyte battery according to any one of claims 1 to 3.
The binder composition for a non-aqueous electrolyte battery according to any one of claims 1 to 4, wherein the content of the component (B) in the binder composition is 50.0 to 99.9% by weight.
An aqueous binder solution for a non-aqueous electrolyte battery comprising the binder composition according to any one of claims 1 to 5 and water.
A slurry composition for a non-aqueous electrolyte battery, comprising the binder composition according to any one of claims 1 to 5, an active material, and water.
An electrode for a non-aqueous electrolyte battery, wherein a mixed layer containing the binder composition according to any one of claims 1 to 5 and an active material is bound to a current collector.
A nonaqueous electrolyte battery comprising the electrode for a nonaqueous electrolyte battery according to claim 8.