KR102075897B1 - Electrode for electrochemical elements - Google Patents

Abstract

An electrode for electrochemical elements comprising an electrode active material layer containing an electrode active material and a binder, wherein at least a part of the binder has a particle shape, and the roundness of the particles is 0.50 to 0.85.

Description

Electrode for electrochemical device {ELECTRODE FOR ELECTROCHEMICAL ELEMENTS}

The present invention relates to an electrode for an electrochemical device.

The demand for electrochemical devices such as lithium ion secondary batteries, which are compact, light weight, high in energy density, and capable of repeating charging and discharging, is expected to increase in future. Lithium ion secondary batteries have a high energy density and are used in fields such as mobile phones and notebook personal computers. In addition, electrochemical devices are required to further improve performance, such as lower resistance and higher capacity, with the expansion and development of applications.

For example, in patent document 1, it has a core shell structure, and the electrode is obtained using the binder which is a specific gel content rate.

Japanese Unexamined Patent Publication No. 2013-182765

In recent years, the demand for making the charging time of an electrochemical device as short as possible increases, and rapid charging by reducing the resistance at the time of charging is increasingly required.

However, the electrode for electrochemical elements obtained by the technique of the above-mentioned patent document 1 can prevent charging / discharging efficiency from falling even when repeated charging / discharging is carried out, Furthermore, since electrode density is high, although it is high capacity, it is such an electric Even in the case of using the electrode for chemical elements, there were additional problems in the increase of the internal resistance and the cycle characteristics at the time of rapid charging.

An object of the present invention is to provide an electrode for an electrochemical device having low internal resistance and excellent balance between cycle characteristics and peel strength when attached to a battery.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to achieve the said objective, when the binder in an electrode for electrochemical elements is made into the specific shape, it is excellent in the diffusibility of lithium at the time of quick charge, and when it mounts in a battery by this, The inventors found out that the internal resistance was low and the cycle characteristics were excellent, and the present invention was completed.

That is, the present invention is as follows.

[1] An electrode for an electrochemical device, comprising an electrode active material layer containing an electrode active material and a binder,

At least a part of the binder has a particle shape, and the roundness of the particles is 0.50 to 0.85, the electrode for electrochemical elements.

[2] The electrode for electrochemical elements according to [1], wherein the average particle long diameter of the binder particles measured by cross-sectional observation is 100 to 400 nm.

[3] The electrode for electrochemical elements according to [1] or [2], wherein the binder is a (co) polymer containing a double bond.

[4] The electrode for electrochemical elements according to any one of [1] to [3], wherein the gel content of the binder is 90 to 100%.

[5] An electrochemical device comprising the electrode for electrochemical device according to any one of [1] to [4].

[6] A lithium ion battery containing the electrode for electrochemical element, separator, and electrolyte solution in any one of [1]-[4].

[7] An automobile provided with the lithium ion battery according to [6].

Industrial Applicability According to the present invention, an electrode for an electrochemical device having low internal resistance when mounted on a battery and excellent in balance between cycle characteristics and peel strength can be provided.

1 is an example of a cross-sectional photograph of an electrode active material layer.
FIG. 2 is a trace of the contour of binder particles in the cross-sectional photograph of FIG. 1. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. This invention is not limited to this, A various deformation | transformation is possible in the range which does not deviate from the summary.

This embodiment is an electrode for electrochemical elements provided with the electrode active material layer containing an electrode active material and a binder, At least one part of the said binder has a particle shape, The roundness of the particle | grains is 0.50 to 0.85 for electrochemical elements Electrode.

The electrode for electrochemical elements of this embodiment should just be an electrode used for an electrochemical element, and is not specifically limited to an electrochemical element, For example, a lithium ion secondary battery, an electric double layer capacitor, a hybrid capacitor (lithium ion capacitor, etc.) Electrodes for various electrochemical elements, such as), are mentioned.

In this embodiment, the electrode active material layer which comprises the electrode for electrochemical elements contains at least an electrode active material and a binder. Hereinafter, the electrode active material and binder which comprise an electrode active material layer are demonstrated.

(Electrode active material)

In this embodiment, an electrode active material is suitably selected according to the kind of electrochemical element. For example, when using the electrode for electrochemical elements as a negative electrode for lithium ion secondary batteries, as a negative electrode active material, these graphitizable carbon, a hard graphitizable carbon, activated carbon, pyrolytic carbon, etc. Low crystalline carbon (amorphous carbon), graphite (natural graphite, artificial graphite), carbon nanowalls, carbon nanotubes, or a composite carbon material of carbon having different physical properties, alloy materials such as tin or silicon, silicon oxide, Oxides such as tin oxide, vanadium oxide, lithium titanate, polyacene and the like.

In addition, the electrode active material illustrated above may be used independently, suitably according to a use, and may be used in mixture of multiple types.

It is preferable that the shape of the negative electrode active material for lithium ion secondary batteries is grain-shaped, and if a particle shape is spherical, a higher density electrode can be formed at the time of electrode shaping | molding. Moreover, the volume average particle diameter of the negative electrode active material for lithium ion secondary batteries is 0.1-100 micrometers normally, Preferably it is 0.5-50 micrometers, More preferably, it is 0.8-20 micrometers. In addition, the tap density of the negative electrode active material for a lithium ion secondary battery is not particularly limited, but preferably 0.6 g / cm 3 or more in the negative electrode.

(bookbinder)

Although it will not restrict | limit especially if it is a compound which can mutually bind the above-mentioned electrode active material as a binder used by this invention, It is preferable that it is a (co) polymer which has a double bond. It is preferable that it is a (co) polymer which superposed | polymerized the monomer containing conjugated diene as a (co) polymer which has a double bond, and it is more preferable to contain ethylenic unsaturated carboxylic acid as a monomer.

When the binder is a (co) polymer obtained by polymerizing a monomer containing a conjugated diene, in addition to the conjugated diene and ethylenically unsaturated carboxylic acid to be contained, other monomers copolymerizable with these, for example, vinyl compounds You may contain it.

Moreover, although the supply form of the binder at the time of electrode manufacture is not specifically limited, For example, it is preferable to use what is a form of copolymer latex in which binder particle was disperse | distributed to water as a raw material.

When the binder is a (co) polymer containing a conjugated diene as a monomer, as the conjugated diene, for example, 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, chloroprene or the like may be used alone or in two. One or more types can be used in combination, and among these, 1, 3- butadiene is preferable from an adhesive viewpoint.

When the copolymer contains an ethylenically unsaturated carboxylic acid as a monomer, examples of the ethylenically unsaturated carboxylic acid include fumaric acid, itaconic acid, acrylic acid, methacrylic acid, and the like. It can use combining a species or more. Among these, itaconic acid and acrylic acid are preferable from the viewpoint of the stability of the polymerized copolymer latex.

When the total amount of the ethylenically unsaturated carboxylic acid is 100 parts by mass of the total monomers, preferably 0.01 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, still more preferably 0.01 to 10 parts by mass. It is below a mass part.

As another vinyl compound which can be copolymerized, an aromatic vinyl compound, a (meth) acrylate compound, a vinyl cyanide compound, etc. are mentioned.

As an aromatic vinyl compound, styrene, (alpha) -methylstyrene, p-methylstyrene, vinyltoluene, chlorstyrene, divinylbenzene, etc. can be used individually by 1 type or in combination of 2 or more types, Among these, Styrene is preferred in view of the stability of the polymerized copolymer latex.

The amount of the aromatic vinyl compound used is preferably 30 to 70 parts by mass, more preferably 35 to 65 parts by mass, still more preferably 35 to 60 parts by mass.

As a (meth) acrylate compound, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth), for example Acrylate, i-butyl (meth) acrylate, n-amyl (meth) acrylate, i-amyl (meth) acrylate, hexyl (meth) acrylate, 2-hexyl (meth) acrylate, octyl (meth) Acrylate, i-nonyl (meth) acrylate, decyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, ethylene glycol (meth) acrylate, etc. Two or more types can be used in combination, and among these, methyl methacrylate is preferable from a stability viewpoint of the polymerized copolymer latex.

0.1-30 mass parts is preferable, as for the usage-amount of a (meth) acrylate compound, More preferably, it is 0.1-25 mass parts, More preferably, it is 0.1-20 mass parts.

As a vinyl cyanide compound, an acrylonitrile, methacrylonitrile, the (alpha)-chloro acrylonitrile etc. are mentioned, for example, These monomers can be used individually by 1 type or in combination of 2 or more types, Among them, acrylonitrile is preferred from the viewpoint of stability of the polymerized copolymer latex.

0.1-30 mass parts is preferable, as for the usage-amount of a vinyl cyanide compound, More preferably, it is 0.1-20 mass parts, More preferably, it is 0.1-15 mass parts.

As a vinyl compound which can be copolymerized, A monomer containing hydroxyl groups, such as 2-hydroxyethyl acrylate, in addition to the above; Aminoalkyl esters such as aminoethyl acrylate, dimethylaminoethyl acrylate and diethylaminoethyl acrylate; Pyridines such as 2-vinylpyridine and 4-vinylpyridine; Glycidyl esters such as glycidyl acrylate and glycidyl methacrylate; Amides such as acrylamide, methacrylamide, N-methylol acrylamide, glycidyl methacrylamide, and N, N-butoxymethylacrylamide; Carboxylic acid vinyl esters, such as vinyl acetate; Vinyl halides such as vinyl chloride; Polyfunctional vinyl monomers such as divinylbenzene, (poly) ethylene glycol di (meth) acrylate, hexanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate and allyl (meth) acrylate Can be mentioned.

These can be used individually by 1 type or in combination of 2 or more type. Usually, a compounding quantity is 0.1-30 mass parts.

From the viewpoint of the stability of the copolymer latex obtained, it is preferable to mix | blend a hydroxyl group containing monomer as another monomer which can be copolymerized, and it is more preferable to mix | blend 2-hydroxyethyl acrylate among these.

As a molecular weight modifier, Halogenated hydrocarbons, such as chloroform and carbon tetrachloride; mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan and thioglycolic acid; Xanthogens such as dimethyl xanthene disulfite and diisopropyl xanthene disulfite; Any that can be used in conventional emulsion polymerization such as terpinolene and α-methylstyrene dimer can be used.

It is preferable that the usage-amount of a molecular weight modifier is 0-5 mass parts with external water with respect to 100 mass parts of all monomers, and (alpha) -methylstyrene dimer and t-dodecyl mercaptan are used preferably.

When the (co) polymer latex is used as a raw material of the binder, the average particle diameter of the binder raw material particles in the (co) polymerized latex is preferably 100 to 400 nm, more preferably 200 to 350 nm. This particle diameter is the volume average particle diameter measured by the dynamic light scattering method.

By making the average particle diameter of binder raw material particle into the said range, making the stability in preparing the slurry-like composition for manufacturing an electrode active material layer favorable, it adjusts the binder particle diameter in the electrode for electrochemical elements obtained to a preferable range. The strength and flexibility of the electrode for an electrochemical device can be better.

In this embodiment, the gel content rate of a binder becomes like this. Preferably it is 90 to 100%, More preferably, it is 95 to 100%.

In addition, the gel content rate of a binder is a value which shows the molecular weight and degree of crosslinking degree of the binder particle in the (co) polymer latex when the (co) polymer latex is used as a raw material of a binder, and can be measured by the method as described in an Example. have.

As the gel content is higher, the fusion of the binder particles in the electrode active material layer can be prevented, that is, the binder can easily maintain the particle shape, and further, the roundness of the binder particles can be increased. Moreover, since the solvent resistance of the copolymer which comprises binder particle | grains is maintained and it does not swell by electrolyte solution inside a battery, the fall of the adhesive force between an electrical power collector-electrode active material and an electrode active material-electrode active material is suppressed.

(Co) polymer latex can be obtained by emulsion-polymerizing the said monomer. At the time of superposition | polymerization, suitable seed particle | grains can be used and seed particle | grains can also be obtained by normal emulsion polymerization. Moreover, when performing emulsion polymerization, a well-known method can be employ | adopted and can be manufactured using an emulsifier, a polymerization initiator, a molecular weight modifier, a chelating agent, a PH regulator, etc. suitably in an aqueous medium.

Here, as an emulsifier, anionic surfactant, nonionic surfactant, amphoteric surfactant, reactive surfactant, etc. can be used individually or in combination of 2 or more types.

Examples of the anionic surfactants include sulfate esters of higher alcohols, alkylbenzene sulfonates, aliphatic sulfonates, sulfate esters of polyethylene glycol alkyl ethers, and the like. As alkyl benzene sulfonate, sodium dodecyl benzene sulfonate is preferable.

As nonionic surfactant, the alkyl ester type, alkyl ether type, alkylphenyl ether type, etc. of polyethyleneglycol are used.

Amphoteric surfactants include betaines such as lauryl betaine and stearyl betaine, amino acid types such as lauryl beta-alanine, stearyl beta-alanine, and lauryl di (aminoethyl) glycine. Used.

Examples of the reactive surfactant include polyoxyethylene alkyl propenyl phenyl ether, α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene, and the like. Can be mentioned.

The amount of the emulsifier used is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 8 parts by mass, still more preferably 0.1 to 6 parts by mass relative to 100 parts by mass of the total monomers.

Examples of the polymerization initiator include water-soluble polymerization initiators such as sodium persulfate, potassium persulfate and ammonium persulfate, oil-soluble polymerization initiators such as benzoyl peroxide and lauryl peroxide, and redox-based polymerization initiators in combination with a reducing agent. It may be used alone or in combination.

As for the usage-amount of a polymerization initiator, 0.1-3 mass parts is preferable with respect to 100 mass parts of all monomers.

It is preferable that content of a binder in the electrode active material layer of the electrode for electrochemical elements is 0.1-10 mass parts on a dry mass basis with respect to 100 mass parts of electrode active materials, More preferably, it is 0.3-8 mass parts, More Preferably it is 0.5-5 mass parts. When content of a binder exists in this range, adhesiveness of an electrode active material layer and an electrical power collector can fully be ensured, and internal resistance can be reduced.

Moreover, when content of a binder exceeds 10 mass parts with respect to 100 mass parts of electrode active materials, it exists in the tendency for binder particles to fuse | melt or the roundness of the binder particle which has a particulate form becomes easy to become remarkably low.

(Composition for electrode)

In this embodiment, the composition for electrodes which comprises an electrode active material layer may contain the other component as needed in addition to the binder mentioned above and the electrode active material mentioned above.

As such another component, additives, such as a nonionic or anionic surfactant as an stabilizer of a electrically conductive material, a dispersing agent, and copolymer latex, an antifoamer, etc. are mentioned.

The conductive material may be any particulate material having conductivity, and is not particularly limited. Examples thereof include conductive carbon blacks such as furnace black, acetylene black, and Ketjen black; Graphite such as natural graphite and artificial graphite; Carbon fibers such as polyacrylonitrile-based carbon fibers, pitch-based carbon fibers, and vapor phase carbon fibers; Can be mentioned. Among these, acetylene black and Ketjen black are preferable. Although the average particle diameter of a electrically conductive material is not specifically limited, It is preferable that it is smaller than the average particle diameter of an electrode active material, Usually, it is 0.001-10 micrometers, More preferably, it is 0.05-5 micrometers, More preferably, it is the range of 0.01-1 micrometer. If the average particle diameter of a electrically conductive material exists in the said range, sufficient electroconductivity can be expressed by a smaller usage amount. Although the usage-amount of a electrically conductive material in the case of adding a electrically conductive material will not be specifically limited if it is a range which does not impair the effect of this invention, Preferably it is 0.1-50 mass parts with respect to 100 mass parts of electrode active materials, More preferably, Is 0.5-15 mass parts, More preferably, it is 1-10 mass parts. By making the content rate of a electrically conductive material into the said range, internal resistance can fully be reduced, maintaining the capacity | capacitance of the electrochemical element obtained high.

A dispersing agent is a component which has the effect | action which disperse | distributes each component uniformly in a solvent, when dispersing or dissolving an electrode active material, a binder, and the arbitrary components added as needed in slurry. Specific examples of the dispersant include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose and hydroxypropyl cellulose, alginate esters such as ammonium salts or alkali metal salts and propylene glycol esters, and alginic acid such as sodium alginate. Polyacrylic acid (or methacrylic acid) salts such as salts, polyacrylic acid, and sodium polyacrylic acid (or methacrylic acid), polyvinyl alcohol, modified polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, polycarboxylic acid, Starch oxide, phosphate starch, casein, various modified starches, chitin, chitosan derivatives, and the like. Moreover, the water-soluble polymer (specific group containing water-soluble polymer) containing 1 or more types, Preferably 2 or more types of groups, such as a carboxyl group, a sulfonic acid group, a fluorine-containing group, a hydroxyl group, and a phosphoric acid group, can also be used as a dispersing agent.

These dispersing agents can be used individually or in combination of 2 types or more, respectively. Especially, a cellulose polymer is preferable and carboxymethylcellulose, its ammonium salt, or an alkali metal salt is especially preferable.

Although the content rate of a dispersing agent in the case of adding a dispersing agent will not be specifically limited if it is a range which does not impair the effect of this invention, It is 0.1-10 mass parts normally with respect to 100 mass parts of electrode active materials, Preferably It is the range of 0.5-5 mass parts, More preferably, it is 0.8-2 mass parts.

When copolymer latex is used as a raw material of a binder, water can be used as a dispersion medium of copolymer latex, and when obtaining by emulsion-polymerizing binder particle as mentioned above, the water dispersion medium used at the time of superposition | polymerization is used as it is, or It can be used by concentrating this. Moreover, a dispersion medium can be substituted and used with the organic solvent which is optimal for an active material as needed. Although it does not specifically limit about such an organic type dispersion medium, A substitution method is not specifically limited, For example, the method of adding an organic dispersion medium to the copolymer latex obtained by emulsion polymerization, and volatilizing water by distillation under reduced pressure, and water from the said copolymer latex The method of volatilizing and redispersing the obtained solid content in an organic dispersion medium, etc. are mentioned.

(Method for Producing Electrode)

Next, the manufacturing method of the electrode for electrochemical elements of this embodiment is demonstrated.

In the case of a lithium ion battery electrode, it is obtained by first forming a slurry-like composition for electrodes, apply | coating this electrode composition on electrical power collectors, such as copper foil, drying, and press molding, and forming an electrode active material layer.

Although an electrode active material layer is formed on an electrical power collector, the formation method is not restrict | limited.

In addition, the slurry composition for electrodes is kneaded by mixing an electrode active material, a conductive material, an essential component of a binder, and other dispersing agents and additives in water or an organic solvent such as N-methyl-2-pyrrolidone or tetrahydrofuran. It can manufacture.

Although the solvent used in order to obtain the composition for electrodes is not specifically limited, When using the said dispersing agent, the solvent which can melt | dissolve a dispersing agent is used preferably. Specifically, water is usually used, but an organic solvent may be used, or a mixed solvent of water and an organic solvent may be used. As an organic solvent, For example, Alkyl alcohol, such as methyl alcohol, ethyl alcohol, propyl alcohol; Alkyl ketones such as acetone and methyl ethyl ketone; Ethers such as tetrahydrofuran, dioxane and diglyme; Amides such as diethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylimidazolidinone; Sulfur solvents such as dimethyl sulfoxide and sulfolane; Etc. can be mentioned. Among these, alcohols are preferable as the organic solvent. The slurry is preferably an aqueous slurry containing water as a dispersion medium because of ease of drying of the slurry and excellent load on the environment. When water and an organic solvent with a boiling point lower than water are used together, a drying speed can be accelerated at the time of spray drying. Moreover, the dispersibility of a binder or the solubility of a dispersing agent changes with the quantity or kind of organic solvent used together with water. Thereby, the viscosity and fluidity of a slurry can be adjusted and production efficiency can be improved.

The quantity of the solvent used when preparing the composition for electrodes is an amount whose solid content concentration is 1-90 mass% normally, Preferably it is 5-85 mass%, More preferably, it becomes the range of 10-80 mass%. When solid content concentration exists in this range, since each component is disperse | distributing uniformly, it is preferable.

The method or order of dispersing or dissolving an electrode active material, a conductive material, a binder, and other dispersing agents or additives in a solvent is not particularly limited. For example, an electrode active material, a conductive material, a binder, and other dispersing agents or additives are added to a solvent. Mixing by mixing; A method of dissolving a dispersant in a solvent, adding and mixing a binder dispersed in a solvent, and finally adding and mixing an electrode active material and a conductive material; The electrode active material and the electrically conductive material are added and mixed with the binder disperse | distributed to the solvent, The method of adding and mixing the dispersing agent dissolved in the solvent, etc. are mentioned. As a mixing means, mixing apparatuses, such as a ball mill, a sand mill, a bead mill, a pigment disperser, a disintegrator, an ultrasonic disperser, a homogenizer, a homo mixer, a planetary mixer, are mentioned, for example. Mixing is normally performed in the range of room temperature-80 degreeC, for 10 minutes-several hours.

The viscosity of the composition for electrodes is 10-100,000 mPa * s normally at room temperature, Preferably it is 30-500,000 mPa * s, More preferably, it is the range of 50-20,000 mPa * s. If the viscosity of the composition for electrodes exists in this range, productivity can be raised.

The coating method on the current collector of the composition for electrodes is not particularly limited. For example, methods, such as a doctor blade method, a dip method, the reverse roll method, the direct roll method, the gravure method, the extrusion method, the brush coating method, are mentioned. The coating thickness of the composition for electrodes is suitably set according to the thickness of the target electrode active material layer.

As a drying method, the drying method by irradiation with warm air, hot air, low humidity wind, vacuum drying, (far) infrared rays, an electron beam, etc. are mentioned, for example. Especially, the drying method by irradiation of far infrared rays is preferable. As for a drying temperature and a drying time, the temperature and time which can remove the solvent in the composition for electrodes apply | coated to an electrical power collector are preferable, As a drying temperature, it is 50-300 degreeC, Preferably it is 50-250 degreeC. As drying time, it is about 3 hours-about 100 hours normally, Preferably it is 5 hours-50 hours, More preferably, it is 10 hours-30 hours.

As a press molding method, shaping | molding methods, such as roll press and press press, are mentioned. 1-10 t / cm <2> is preferable for the pressure at the time of press molding, and the density of an electrode active material layer can be further adjusted by setting the temperature and time at the time of press molding suitably.

The density (electrode density) of the electrode active material layer is preferably 0.30 to 2.0 g / cm 3, more preferably 0.35 from the viewpoint of the binder having a particle shape and adjusting the roundness of the particles to the range defined by the present invention. To 1.9 g / cm 3, more preferably 0.40 to 1.8 g / cm 3. When the electrode density is 2.0 g / cm 3 or less, it is possible to prevent the binders from fusing together and the roundness is remarkably lowered to fall outside the range defined by the present invention. In addition, the higher the electrode density of the electrode, the larger the battery capacity per volume, but if the electrode density is too high, the cycle characteristics tend to be lowered.

Moreover, the thickness of an electrode active material layer is not specifically limited, Usually, 5-1000 micrometers, Preferably it is 20-500 micrometers, More preferably, it is 30-300 micrometers.

(Structure of Electrochemical Device Electrode)

Next, the structure of the electrode for electrochemical elements of this embodiment is demonstrated. In this embodiment, the electrode for electrochemical elements has at least an electrode active material layer, and this electrode active material layer may be formed on electrical power collectors, such as copper foil, for example.

In this embodiment, an electrode active material layer contains an electrode active material and a binder, and at least one part of the binder exists in the form which has the particle shape in an electrode active material layer. The roundness of the particles is 0.50 to 0.85.

Since the binder has a particle shape in the electrode active material layer, the void portions are secured to the binders adjacent to each other. Therefore, when an electrochemical element is obtained using such an electrode for electrochemical elements, lithium ions can be easily diffused into the electrode active material layer by passing through this gap portion, thereby reducing internal resistance.

In the cross-sectional photograph of the electrode active material layer, it is preferable that 70% or more have a particle shape in the area ratio of the binder when the contour of the binder particles is traced, more preferably 80% or more, and still more preferably 90% or more. .

Specifically, the cross-sectional photograph of the electrode active material layer is taken by SEM, and the part judged as a binder does not have the part and particle shape confirmed to have a particle shape similarly to the measurement of roundness mentioned later. It divides into parts and calculates it based on the area of both.

In addition, by controlling the roundness of the binder particles having a particle shape in the electrode active material layer, by securing the adhesion area between the active material or the current collector and the binder and the voids, the internal resistance can be reduced, and the peel strength and cycle characteristics can be reduced. Improvements can be made possible.

The roundness of the binder particles having a particulate form in the electrode active material layer is preferably 0.55 to 0.80, more preferably 0.70 to 0.80.

The roundness of the binder particles having a particulate form in the electrode active material layer is preferably higher in terms of securing the voids, but is preferably not too high in terms of cycle characteristics and peel strength. If the roundness is too high, the cycle characteristics may deteriorate due to peeling of the binder because it cannot cope with expansion and contraction of the active material, or when the current collector-electrode active material or the electrode active material-electrode active material are adhered to each other, the contact area becomes excessive and the adhesion area is excessive It is thought that the peel strength decreases due to the decrease in size, but the mechanism does not comply with it.

The roundness of the binder particles in the electrode active material layer depends on, for example, the average particle size of the binder particles in the (co) polymer latex, which is a raw material of the binder, the gel content, the content of the binder in the electrode active material layer, and the density of the electrode active material layer. I can adjust it.

Specifically, the smaller the average particle diameter, the higher the roundness can be increased without being easily crushed by the pressure at the time of press molding, and the larger the average particle diameter can be easily crushed by the pressure at the time of press molding, thereby lowering the roundness. And the higher the gel content rate, the higher the roundness of the binder particle shape in the electrode active material layer. In addition, the larger the content of the binder, the lower the roundness. In particular, when the content exceeds 10 parts by mass, the binders are fused or the roundness is remarkably lowered. Further, the higher the density of the electrode active material layer, the lower the roundness. In particular, when it exceeds 2.0 g / cm 3, the binders are fused or the roundness is remarkably lowered, making it difficult to make the range defined in the present invention.

In addition, the roundness of the binder particle in an electrode active material layer shows what was computed by the following method.

The site showing dark contrast at the site determined by the binder in the cross-sectional photograph (FIG. 1) of the electrode active material layer photographed by SEM, and judged as the boundary (contour) of the particle was determined as the boundary (contour) of the line. Trace the contours of the binder particles by hand (FIG. 2). From this trace diagram, 100 binder particles having a random particle shape are selected. At this time, the particle whose contour is unclear is not selected (it is not used for calculating roundness). Moreover, when it does not have clear dark contrast in an observation image, it determines with no particle shape.

The contour image of each selected particle is processed with image analysis software (Azo group, imageJ, etc.), the roundness is calculated from the area and the perimeter length of the area enclosed by the contour, and the arithmetic mean is calculated from the roundness. Shall be. When the contour of 100 binder particles cannot be extracted from one visual field, 100 contours are extracted from multiple visual fields, and roundness is calculated.

Roundness = 4π × area / (circle length ² )

It is preferable that the particle diameter of the binder particle in an electrode active material layer is 50-1000 nm as an average particle long diameter measured by cross-sectional observation. By the said average particle long diameter being in this range, the intensity | strength and flexibility of the electrode for electrochemical elements become more favorable.

The average particle long diameter is more preferably 100 to 900 nm, still more preferably 200 to 800 nm.

The average particle long diameter selects 100 binder particles randomly having a particle shape from the trace diagram (Fig. 2) of the cross-sectional photograph of the electrode active material layer photographed by the SEM in the same manner as the calculation of the roundness of the binder particles. Then, the outline image of each selected particle is processed by image analysis software (Azo group, imageJ, etc.), and the arithmetic mean of the long diameter of the area | region enclosed by the outline is made into the average particle long diameter.

(Electrochemical element)

The electrode for electrochemical elements of this embodiment can be used as an electrode in electrochemical elements, such as a lithium ion secondary battery, an electric double layer capacitor, a lithium ion capacitor, a sodium battery, a magnesium battery, and is especially preferable in a lithium ion secondary battery. It can be used easily, and it can use especially for the negative electrode of a lithium ion secondary battery.

For example, a lithium ion secondary battery is comprised from this electrode for electrochemical elements, a separator, and electrolyte solution.

(Separator)

The separator is not particularly limited as long as the separator can insulate between the electrodes for electrochemical elements and can pass cations and anions. Specifically, (a) a porous separator having pores, (b) a porous separator having a polymer coat layer formed on one or both surfaces thereof, or (c) a porous separator having a porous resin coat layer containing inorganic ceramic powder. have. Non-limiting examples of these include polypropylene-based, polyethylene-based, polyolefin-based, or aramid-based porous separators, polyvinylidene fluorides, polyethylene oxides, polyacrylonitrile or polyvinylidene fluoride hexafluoropropylene copolymers, and the like. Polymer film for solid polymer electrolyte or gel polymer electrolyte, a separator coated with a gelling polymer coat layer, or a separator coated with a porous membrane layer composed of an inorganic filler and a dispersant for an inorganic filler. A separator is arrange | positioned between a pair of electrodes for electrochemical elements arrange | positioned so that an electrode active material layer may oppose, and an element is obtained. Although the thickness of a separator is suitably selected according to a use purpose, Usually, it is 1-100 micrometers, Preferably it is 10-80 micrometers, More preferably, it is 20-60 micrometers.

(Electrolyte amount)

Although electrolyte solution is not specifically limited, For example, what melt | dissolved lithium salt in the non-aqueous solvent as a supporting electrolyte can be used. Examples of lithium salts include LiPF ₆ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAlCl ₄ , LiClO ₄ , CF ₃ SO ₃ Li, C ₄ F ₉ SO ₃ Li, CF ₃ COOLi, (CF ₃ CO) _{2 NLi, (CF 3 SO 2} ) 2 NLi, (C 2 F 5 SO 2) can be cited lithium salts such as NLi. LiPF ₆ , LiClO ₄ , CF ₃ SO ₃ Li, which is particularly soluble in a solvent and exhibits high dissociation degree, is preferably used. These can be used individually or in mixture of 2 or more types. The amount of the supporting electrolyte is usually 1% by mass or more, preferably 5% by mass or more, and usually 30% by mass or less, preferably 20% by mass or less with respect to the electrolyte solution. Even if the amount of the supporting electrolyte is too small or too large, the ionic conductivity is lowered and the charging and discharging characteristics of the battery are lowered.

The solvent used for the electrolytic solution is not particularly limited as long as it dissolves the supporting electrolyte. Typically, dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate ( BC) and alkyl carbonates, such as methyl ethyl carbonate (MEC); ethers such as esters such as γ-butyrolactone and methyl formate, 1,2-dimethoxyethane, and tetrahydrofuran; Sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; Is used. In particular, dimethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, and methyl ethyl carbonate are preferable because high ion conductivity is easily obtained and the use temperature range is wide. These can be used individually or in mixture of 2 or more types. Moreover, you may use it, containing an additive in electrolyte solution. Moreover, as an additive, carbonate type compounds, such as vinylene carbonate (VC), are preferable.

As electrolyte solution of that excepting the above, the gel polymer electrolyte which impregnated electrolyte solution with polymer electrolytes, such as polyethylene oxide and polyacrylonitrile, and inorganic solid electrolytes, such as lithium sulfide, LiI, Li3N, are mentioned.

A secondary battery is obtained by superimposing a negative electrode and a positive electrode through a separator, winding this in accordance with a battery shape, or folding it into a battery container, injecting an electrolyte solution into a battery container, and sealing it. Furthermore, if necessary, an overcurrent prevention element such as an expanded metal, a fuse, a PTC element, a lead plate, or the like may be placed to prevent an increase in pressure inside the battery and overcharge / discharge. The shape of the battery may be any of a laminate cell type, a coin type, a button type, a sheet type, a cylindrical shape, a square shape, and a flat type.

Examples of the lithium ion secondary battery in the present embodiment include a mobile phone, a portable computer, a smartphone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle), a UAV (Unmanned Aerial Vehicle), an automobile, And power storage devices and the like. As an automobile, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. are mentioned, for example.

Example

Below, an Example and a comparative example are given and this invention is demonstrated more concretely. Parts and% in each example are mass references | standards unless there is particular notice.

In addition, the definition and evaluation method of each characteristic are as follows.

<Particle diameter of binder particle>

About the particle diameter of binder particle | grain (latex), it calculated | required by measuring the volume average particle diameter by the dynamic light scattering method using the micro track ultrafine particle size analyzer (W) UPA-150 (made by Nikkiso Corporation).

<Gel content of binder>

The copolymer latex was applied to a glass plate at a thickness of 0.5 mm and 0.5 g was weighed from a coating film (dry coating film of the copolymer before immersion) obtained by drying at 130 ° C. for 30 minutes, and then immersed in 40 ml of toluene for 3 hours. Shaken. The copolymer coating film after shaking was filtered with 325 mesh stainless steel wire mesh, and it dried at 130 degreeC for 1 hour, and obtained the dry coating film of the copolymer after immersion, and this was weighed. The gel content was calculated by the following formula from the mass of the coating film (dry coating film) before and after immersion.

<Density (electrode density) of the electrode active material layer>

About the electrode active material layer (negative electrode active material layer) of the negative electrode obtained by the Example and the comparative example, the area C (cm <2>), thickness D (micrometer), the mass A (g) of an electrical power collector, and the produced electrode for electrochemical elements From the mass B (g), the density was calculated by the following formula.

Density (electrode density) of the electrode active material layer (g / cm 3)

= (B (g)-A (g)) / (C (cm 2) × D (μm) × 10 ^-4 )

<Roundness of binder particle>

About the cross section of the electrode active material layer (negative electrode active material layer) of the negative electrode obtained by the Example and the comparative example, the scanning magnification 50,000 times and acceleration voltage 5.0 kV using a scanning electron microscope (product name "S4700", the Hitachi High-Tech company make). , Detector: A cross-sectional photograph was taken by setting the reflected electrons, and the roundness of the binder particles in the negative electrode active material layer was measured by the following method.

In the preparation of the cross section of the negative electrode active material layer, first, the laminated secondary cell-shaped lithium secondary battery was disassembled in an Ar glove box, and the recovered negative electrode was washed with dimethyl carbonate and then dried in air. Next, the negative electrode after drying was cut out to 2 mm square, and after carrying out the OsO4 dyeing process, the cross section was produced perpendicular to the electrode surface using the cross section polisher (product name "SM-09010", the Nippon Electronics Corporation make).

Using the cross-sectional photograph taken by the above method, 100 binder particles were randomly selected, and from the site judged as the binder, the site showing the dark contrast in the observation image, and the line showing the linear and continuous connection were obtained. Judging by the boundary (outline), the outline of the binder particles was traced by free hand. As for the particles whose contours are unclear, no roundness was used to calculate the roundness. Moreover, when it did not have clear dark contrast in an observation image, it judged that it did not have a particle shape, and made it "measurement impossible". The obtained contour image was processed with image analysis software (imageJ), and roundness was calculated from the following formula from the area and the perimeter length of the area | region enclosed by contour, and the arithmetic mean was made into roundness. When the contour of 100 binder particles could not be extracted from one visual field, 100 contours were extracted from multiple visual fields, and roundness was calculated.

Roundness = 4π × area / (circumference length ² )

<Average particle long diameter of binder particle>

100 outline images obtained in the above <roundness of the binder particle> were processed by image analysis software (imageJ), and the arithmetic mean of the long diameter of the area | region enclosed by the outline was made into the average particle long diameter.

<Fill strength>

After cutting the negative electrode obtained by the Example and the comparative example into the square of 1 cm x 10 cm in length, respectively, as a test piece, fixing the negative electrode active material layer surface up, and sticking a cellophane tape to the surface of a negative electrode active material layer, The stress at the time of peeling off a cellophane tape in 180 degree direction at the speed | rate of 50 mm / min from one end of a test piece was measured. And this measurement was performed 10 times, the average value was calculated | required, this was made into peeling strength, and it determined by the following reference | standard. Moreover, it can be judged that the adhesive strength in the negative electrode active material layer and the adhesive strength between a negative electrode active material layer and an electrical power collector are high, so that peeling strength is large.

A: Peel strength is 8 N / m or more

B: Peel strength is 6 N / m or more and less than 8 N / m

C: Peel strength is 4 N / m or more and less than 6 N / m

D: Peel strength is more than 2 N / m, less than 4 N / m

E: Peel Strength is less than 2 N / m

<Internal resistance>

About the lithium secondary battery of the laminated laminate cell shape obtained in the Example and the comparative example, it charges by constant current until it becomes 4.2V by the constant current method which made charging rate 2C at 25 degreeC, and then constant voltage at a rated voltage. Was charged. Thereafter, the discharge rate was 2C, and discharged to 3.0V. The voltage drop 10 seconds after the start of discharge was defined as ΔV. And the discharge rate is changed to 2C-10C, similarly, the voltage drop amount (DELTA) V is measured, the discharge current value I (A) and the voltage drop amount (DELTA) V (V) are plotted, and the slope of the straight line is made into internal resistance, It judged on the following criteria.

A: Internal resistance is less than 3.0 Ω

B: Internal resistance is more than 3.0 Ω, less than 3.5 Ω

C: Internal resistance is more than 3.5 Ω, less than 4.0 Ω

D: Internal resistance is more than 4.0 Ω, less than 4.5 Ω

E: internal resistance is more than 4.5 Ω

<Charge / Discharge Cycle Characteristics>

About the lithium secondary battery of the laminated laminate cell shape obtained in the Example and the comparative example, it is charged by constant current until it becomes 4.2V by the constant current constant voltage charging method of 2C at 60 degreeC, Then, it charges by constant voltage then, Charge / discharge cycle test was conducted to discharge to 3.0 V at a constant current of 2 C. The charge / discharge cycle test was performed up to 100 cycles, and the ratio of the discharge capacity at the 100th cycle to the initial discharge capacity was determined based on the following criteria. The larger this value, the smaller the decrease in capacity due to repeated charging and discharging.

A: The capacity retention rate is 90% or more

B: Capacity retention is 80% or more but less than 90%

C: capacity retention rate is 70% or more and less than 80%

D: Capacity retention is 60% or more but less than 70%

E: capacity retention is less than 60%

(Example 1)

<Manufacture of the binder for negative electrodes>

Initially water (75 parts by mass of ion-exchanged water, 3.0 parts by mass of itaconic acid, seed (polystyrene latex having a particle diameter of 35 nm), 0.3 part by mass of an emulsifier (sodium dodecylbenzenesulfonate)) was introduced into the reactor, and the temperature was raised to 80 ° C while stirring. And maintained. Compound monomers (40 parts by mass of 1,3-butadiene, 49 parts by mass of styrene, 3.0 parts by mass of methyl methacrylate, 3.0 parts by mass of acrylonitrile, 1.0 parts by mass of 2-hydroxyethyl acrylate, 1.0 parts by mass of acrylic acid, 0.1 part by mass of α-methylstyrene dimer and 0.1 part by mass of t-dodecyl mercaptan) were further added over 6.5 hours. At the same time, catalyst water (24 parts by mass of ion-exchanged water, 1.2 parts by mass of sodium persulfate, 0.3 parts by mass of caustic soda, and 0.15 parts by mass of emulsifier (sodium dodecylbenzenesulfonate)) was further added. After the addition was completed, the temperature was raised to 95 ° C to react for 1 hour to complete the polymerization. The obtained copolymer latex was steam distilled to remove unreacted monomers.

The volume average particle diameter when the obtained copolymer latex was adjusted to PH 7.0 ± 1.0 with caustic potassium was 300 nm, and the gel content was 98%.

<Production of positive electrode>

As an electrode active material of a positive electrode, 100 parts of lithium cobalt oxides with a volume average particle diameter of 8 micrometers, 2.0 parts of solid content corresponded to 1.5 parts of aqueous solutions of carboxymethylcellulose ammonium (DN-800H: the Daicel Chemical Industry Co., Ltd.) as a dispersing agent, and a conductive material. 5 parts of acetylene black (Denka Black powder: manufactured by Denki Chemical Industry Co., Ltd.) and 40% aqueous dispersion of an acrylate polymer having a glass transition temperature of −28 ° C. and a number average particle diameter of 0.28 μm as a binder for an electrode composition. 3.0 parts of ion content and ion-exchange water were mixed by the planetary mixer so that total solid content concentration might be 35%, and the composition for electrodes of the positive electrode was prepared.

The positive electrode composition was applied to a current collector made of aluminum foil having a thickness of 20 μm on both sides of the current collector at an electrode forming speed of 20 m / min, dried at 120 ° C. for 5 minutes, and then punched in a 5 cm square. And the positive electrode which has an electrode active material layer of single-sided thickness of 100 micrometers was obtained.

<Manufacture of negative electrode>

As an electrode active material of a negative electrode, 100 parts of graphite (KS-6: TimCal Corporation) of volume average particle diameter are 3.7 micrometers, and the 1.5% aqueous solution of carboxymethylcellulose ammonium (DN-800H: the Daicel Chemical Industry Co., Ltd.) solids is used as a dispersing agent. 5 parts of acetylene black (Denka Black powder: manufactured by Denki Chemical Industry Co., Ltd.) as the conductive material, 3.0 parts of the copolymer latex described above as a binder for the electrode composition, and 3.0 parts of the total solid content of the ion-exchanged water. It mixed so that a density | concentration might be 35%, and prepared the slurry-like composition for negative electrodes.

The composition for negative electrodes was apply | coated so that the film thickness after drying might be about 100 micrometers on the single side | surface of the electrical power collector which consists of 18 micrometers copper foil using a comma coater, and it heat-processes at 60 degreeC for 20 hours, and makes a negative electrode active material layer Formed. Subsequently, using a roll press, it rolled so that press pressure might become 2 t / cm <2> with respect to an electrode, and the negative electrode of thickness 50micrometer was obtained.

<Production of battery>

As the positive electrode, the negative electrode, and the separator, a laminated microporous lithium ion battery was manufactured using a polyethylene microporous membrane (film thickness of 25 µm) (Hipoa, manufactured by Asahi Chemical Co., Ltd.). Electrolyte solution is ethylene carbonate, di-ethyl carbonate in a mass ratio of 1: was used as dissolved in a solvent mixture of 2, a concentration of 1.0 ㏖ / liter of LiPF _6.

(Example 2)

When forming a negative electrode active material layer, except having made drying temperature 100 degreeC and drying time 14 hours, it carried out similarly to Example 1, obtained a negative electrode, the lithium ion secondary battery was manufactured using the obtained negative electrode, and the same Was evaluated. The results are shown in Table 1.

(Example 3)

When forming a negative electrode active material layer, except having made drying temperature 150 degreeC and drying time into 10 hours, it carried out similarly to Example 1, obtained a negative electrode, the lithium ion secondary battery was manufactured using the obtained negative electrode, and it was the same Evaluated. The results are shown in Table 1.

(Comparative Example 1)

In rolling using a roll press, a negative electrode was obtained in the same manner as in Example 1 except that the press pressure was 6 t / cm 2 with respect to the electrode, and a lithium ion secondary battery was produced using the obtained negative electrode and evaluated in the same manner. It was. The results are shown in Table 1.

(Comparative Example 2)

<Manufacture of the binder for negative electrodes>

Initially water (75 parts by mass of ion-exchanged water, 3.0 parts by mass of itaconic acid, seed (polystyrene latex having a particle diameter of 35 nm), 0.3 part by mass of an emulsifier (sodium dodecylbenzenesulfonate)) was introduced into the reactor, and the temperature was raised to 80 ° C while stirring. And maintained. Compound monomers (40 parts by mass of 1,3-butadiene, 49 parts by mass of styrene, 3.0 parts by mass of methyl methacrylate, 3.0 parts by mass of acrylonitrile, 1.0 parts by mass of 2-hydroxyethyl acrylate, 1.0 parts by mass of acrylic acid, 0.1 part by mass of α-methylstyrene dimer and 0.8 part by mass of t-dodecyl mercaptan) were further added over 6.5 hours. At the same time, additional catalyst water (24 parts by mass of ion-exchanged water, 1.2 parts by mass of sodium persulfate, 0.3 parts by mass of caustic soda, and 0.15 parts by mass of emulsifier (sodium dodecylbenzenesulfonate)) was added. After the addition was completed, the temperature was raised to 95 ° C to react for 1 hour to complete the polymerization. The obtained copolymer latex was steam distilled to remove unreacted monomers. The volume average particle diameter when the obtained copolymer latex was adjusted to pH 7.0 ± 1.0 with caustic potassium was 300 nm, and the gel content was 75%.

<Manufacture of negative electrode>

Except having used the copolymer latex mentioned above as an binder for electrode compositions, it carried out similarly to Example 1, and prepared the slurry-like composition for negative electrodes, and carried out similarly to Example 1 using the obtained composition for negative electrodes, and obtained the negative electrode. .

<Production of battery>

As a negative electrode, except having used the said negative electrode, it carried out similarly to Example 1, and manufactured the laminated ion cell type lithium ion battery, and evaluated it similarly to Example 1. As a result of observing the photograph which photographed the cross section of the electrode active material layer with the scanning electron microscope, the binder did not have a particle shape. The results are shown in Table 1.

(Comparative Example 3)

<Manufacture of the binder for negative electrodes>

Initially water (75 parts by mass of ion-exchanged water, 3.0 parts by mass of itaconic acid, seed (polystyrene latex having a particle diameter of 35 nm), 0.3 part by mass of an emulsifier (sodium dodecylbenzenesulfonate)) was introduced into the reactor, and the temperature was raised to 80 ° C while stirring. And maintained. Compound monomers (40 parts by mass of butadiene, 49 parts by mass of styrene, 3.0 parts by mass of methyl methacrylate, 3.0 parts by mass of acrylonitrile, 1.0 parts by mass of 2-hydroxyethyl acrylate, 1.0 parts by mass of acrylic acid, α-methylstyrene 0.1 part by mass of dimer and 0.05 parts by mass of t-dodecyl mercaptan) were further added over 6.5 hours. At the same time, catalyst water (24 parts by mass of ion-exchanged water, 1.2 parts by mass of sodium persulfate, 0.3 parts by mass of caustic soda, and 0.15 parts by mass of emulsifier (sodium dodecylbenzenesulfonate)) was further added. After the addition was completed, the temperature was raised to 95 ° C to react for 1 hour to complete the polymerization. The obtained copolymer latex was steam distilled to remove unreacted monomers. The volume average particle diameter when the obtained copolymer latex was adjusted to pH 7.0 ± 1.0 with caustic potassium was 300 nm, and the gel content was 99%.

<Manufacture of negative electrode>

Except having used the copolymer latex mentioned above as an binder for electrode compositions, it carried out similarly to Example 1, and prepared the slurry-like composition for negative electrodes, and carried out similarly to Example 1 using the obtained composition for negative electrodes, and obtained the negative electrode. .

<Production of battery>

As a negative electrode, except having used the said negative electrode, it carried out similarly to Example 1, and produced the laminated ion cell type lithium ion battery, and evaluated it similarly to Example 1. The results are shown in Table 1.

Industrial availability

The electrode for electrochemical elements of this invention can be used as an electrode (positive electrode and a negative electrode) of various electrochemical elements, Especially it can use suitably as a negative electrode of a lithium ion secondary battery.

This application is based on the JP Patent application (Japanese Patent Application No. 2015-160108) of which it applied to Japan Patent Office on August 14, 2015, The content is taken in here as a reference.

Claims (7)

An electrode for an electrochemical device comprising an electrode active material layer containing an electrode active material and a binder,
At least a part of the binder has a particle shape, the roundness of the particles is 0.50 to 0.85,
Content of the said binder is 0.1-10 mass parts on a dry mass basis with respect to 100 mass parts of said electrode active materials,
The average particle long diameter of the said binder particle measured by cross section observation is 50-1000 nm,
The gel content rate of the said binder is 90 to 100%,
The electrode for electrochemical elements whose density of an electrode active material layer is 0.30-2.0 g / cm <3>. delete The method of claim 1,
The electrode for electrochemical elements whose said binder is a (co) polymer which superposed | polymerized the monomer containing conjugated diene. delete The electrochemical element provided with the electrode for electrochemical elements of Claim 1 or 3. The lithium ion battery containing the electrode for electrochemical elements, separator, and electrolyte solution of Claim 1 or 3. An automobile provided with the lithium ion battery according to claim 6.

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