JP2010157564A - Method of manufacturing composite particle for electrochemical element electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method in which composite particles for an electrochemical element electrode which has a small volume-average particle size can be obtained even when the solid concentration of an electrode composition is high. <P>SOLUTION: The present invention relates to the method of manufacturing composite particles for the electrochemical electrode, in which an impulse wave is applied to an atomized electrode composition containing an electrode active substance, a conductive material, and a binding agent after the electrode composition is atomized. Further, the present invention relates to the electrochemical electrode having a current collector and an electrode layer formed by forming a forming material for the electrochemical element electrode which contains the composite particles for the electrochemical element electrode on at least one surface of the current collector. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is suitable for electrodes used in electrochemical elements such as lithium ion secondary batteries, electric double layer capacitors, and lithium ion capacitors (hereinafter sometimes collectively referred to as “electrochemical element electrodes”). The present invention relates to a method for producing a composite particle for an electrochemical element electrode used, and the composite particle for an electrochemical element electrode, and also relates to an electrochemical element electrode formed from an electrode material comprising the composite particle for an electrochemical element electrode. .

  Taking advantage of the small size, light weight, high energy density, and the ability to repeatedly charge and discharge, electrochemical devices such as lithium ion secondary batteries, electric double layer capacitors and lithium ion capacitors are rapidly expanding their demand. ing. Lithium-ion secondary batteries have a relatively high energy density, so they are used in the fields of mobile phones and notebook personal computers. Electric double layer capacitors can be charged and discharged rapidly, so they can be used for small memory backups such as personal computers. It is used as a power source. Furthermore, the electric double layer capacitor is expected to be applied as a large power source for electric vehicles. In addition, lithium ion capacitors that take advantage of lithium ion secondary batteries and electric double layer capacitors are attracting attention because of their high energy density and power density. With the expansion and development of applications, these electrochemical elements are required to further improve characteristics such as low resistance, high capacity, and improved mechanical characteristics. Under such circumstances, in order to improve the performance of the electrochemical device, various improvements have been made on the method for forming the electrode layer of the electrochemical device electrode and the electrode material for forming the electrochemical device electrode.

For example, in Patent Document 1, an electrode active material, a conductive material, a dispersion-type binder, and a soluble resin are dispersed or dissolved in a solvent, and the electrode active material, the conductive material, and the dispersion-type binder are dispersed and dissolved. A method for obtaining composite particles by obtaining an electrode composition in which a resin is dissolved and spray-drying the electrode composition with an atomizer has been introduced. Furthermore, an electrochemical element electrode is obtained by forming the composite particles as an electrode material into a sheet shape by a roll pressure molding method or the like, and laminating on a current collector. An electrochemical element including an electrochemical element electrode manufactured by this method has a low internal resistance and a high capacity.
JP 2006-303395 A

  On the other hand, the inventors have studied reduction of internal resistance by reducing the thickness of the electrode layer for the purpose of further increasing the power density. In the study, when an electrochemical element electrode having a thin film electrode layer is manufactured by the method of Patent Document 1, a material for forming an electrochemical element electrode composed of composite particles having a small volume average particle diameter is used. It was found that a dense thin electrode layer can be obtained.

  However, in order to produce composite particles having a small particle diameter by the method of Patent Document 1, the solid content concentration of the electrode composition had to be lowered. As a result, the problem of reduced productivity occurred. If the moisture evaporation amount of the drying apparatus is R [kg / h], the production amount of the composite particles is W [kg / h], the solid content concentration of the electrode composition is w1, and the moisture content of the composite particles is w2, the following equation is obtained. Narutatsu.

For example, when the moisture evaporation amount of the drying apparatus is 1000 kg / h, when the solid content concentration of the electrode composition is diluted from 20% to 10%, the production amount of the composite particles having a moisture content of 2% is from 256 kg / h to 113 kg / h. It greatly decreases to h (Non-patent Document 1).
Granulation Handbook, edited by Japan Powder Industrial Technology Association (1991)

  Accordingly, an object of the present invention is to provide a production method in which composite particles for electrochemical element electrodes having a small volume average particle diameter can be obtained efficiently even when the solid content concentration of the electrode composition is high.

  As a result of intensive studies, the present inventor provided a shock wave to the sprayed electrode composition in the step of spray drying the electrode composition comprising an electrode active material, a conductive agent, a binder and a solvent, It has been found that even when the solid content concentration of the electrode composition is high, composite particles for electrochemical element electrodes having a small volume average particle diameter can be obtained. The present inventor has completed the present invention based on these findings.

  That is, this invention which solves the said subject contains the following matters as a summary.

Thus, according to the present invention, the following [1] to [10] are provided.
[1] A composite particle for an electrochemical element electrode, characterized by spraying an electrode composition comprising an electrode active material, a conductive agent, a binder and a solvent, and then applying a shock wave to the sprayed electrode composition Manufacturing method.
[2] The method for producing composite particles for an electrochemical element electrode according to [1], wherein the shock wave is a sound wave.
[3] The method for producing composite particles for an electrochemical element electrode according to [2], wherein the sound wave is generated by a pulse combustion gas.
[4] The method for producing composite particles for an electrochemical element electrode according to any one of [1] to [3], wherein the spraying of the electrode composition is spraying by pressurization.
[5] The method for producing composite particles for electrochemical element electrodes according to any one of [1] to [4], wherein the solid content concentration of the electrode composition is 1% by weight or more.
[6] Electrochemical element electrode composite particles obtained by the production method according to any one of [1] to [5].
[7] The composite particle for an electrochemical element electrode according to [6], wherein the volume average particle diameter is 0.1 to 1,000 μm.
[8] An electrochemical element electrode forming material comprising the electrochemical element electrode composite particles according to [6] or [7].
[9] An electrochemical element electrode comprising a current collector and an electrode layer formed of at least one surface on the current collector from the electrochemical element electrode forming material according to [8].
[10] The electrochemical element electrode according to [9], which is for an electric double layer capacitor.
[11] The electrochemical device electrode according to [9], which is for a lithium ion capacitor.

  ADVANTAGE OF THE INVENTION According to this invention, even if the solid content concentration of an electrode composition is high, the composite particle for electrochemical element electrodes with a small volume average particle diameter can be obtained efficiently.

  In the method for producing composite particles for electrochemical element electrodes of the present invention, after spraying an electrode composition comprising an electrode active material, a conductive material, a binder and a solvent, a shock wave is applied to the sprayed electrode composition. It is characterized by that. Hereinafter, each material and each process will be described.

(Electrode composition)
The electrode composition used in the present invention comprises an electrode active material, a conductive agent, a binder and a solvent.

<Electrode active material>
The electrode active material used in the present invention is a substance that transfers electrons within the electrochemical device electrode. The electrode active material mainly includes an active material for a lithium ion secondary battery electrode, an active material for an electric double layer capacitor electrode, and an active material for a lithium ion capacitor electrode.

Examples of the active material for a lithium ion secondary battery electrode include a positive electrode and a negative electrode. Specific examples of the electrode active material used for the positive electrode of the lithium ion secondary battery electrode include lithium-containing composite metal oxides such as LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , and LiFeVO ₄ ; TiS ₂ , transition metal sulfides such as TiS ₃ and 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 _13, etc. Transition metal oxides are exemplified. Furthermore, conductive polymers such as polyacetylene and poly-p-phenylene are listed. Preferred is a lithium-containing composite metal oxide.

  Specific examples of the electrode active material used for the negative electrode of the lithium ion secondary battery electrode include carbonaceous materials such as amorphous carbon, graphite, natural graphite, mesocarbon microbeads (MCMB), and pitch-based carbon fibers; polyacene, etc. Of the conductive polymer. Crystalline carbonaceous materials such as graphite, natural graphite, and mesocarbon microbeads (MCMB) are preferable.

  The shape of the electrode active material used for the lithium ion secondary battery electrode is preferably a granulated particle. When the shape of the particles is spherical, a higher density electrode can be formed at the time of forming the electrode layer.

  The volume average particle diameter of the electrode active material used for the lithium ion secondary battery electrode is usually 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 2 to 10 μm for both the positive electrode and the negative electrode.

The tap density of the electrode active material used for the lithium ion secondary battery electrode is not particularly limited, but is usually 0.5 g / cm ³ or more, preferably 1 g / cm ³ or more, more preferably 2 g / cm ³ or more for the positive electrode. In the negative electrode, it is usually 0.1 g / cm ³ or more, preferably 0.5 g / cm ³ or more, more preferably 0.6 g / cm ³ or more.

  As an electrode active material used for the electric double layer capacitor electrode, a carbon allotrope is usually used. Specific examples of the allotrope of carbon include activated carbon, polyacene, carbon whisker, and graphite, and these powders or fibers can be used. A preferred electrode active material is activated carbon, and specific examples include activated carbon made from phenol resin, rayon, acrylonitrile resin, pitch, coconut shell, and the like.

  The volume average particle diameter of the electrode active material used for the electric double layer capacitor electrode is usually 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 2 to 10 μm.

The specific surface area of the electrode active material used in the electric double layer capacitor electrode, ^{10 m} 2 / g or more, and a preferably 100~5,000m ² / g, more preferably 1,000~3,000m ² / g . Since the density of the obtained electrode layer tends to decrease as the specific surface area of the electrode active material increases, an electrode layer having a desired density can be obtained by appropriately selecting the electrode active material.

The electrode active material used for the lithium ion capacitor electrode includes a positive electrode and a negative electrode. As the electrode active material used for the positive electrode of the lithium ion capacitor electrode, and lithium ion, for example, PF ₆ ^- and anion as long as it can reversibly carry like. Specifically, an allotrope of carbon is usually used, and electrode active materials used in electric double layer capacitors can be widely used. When carbon allotropes are used in combination, two or more types of carbon allotropes having different average particle diameters or particle size distributions may be used in combination. Further, a polyacene organic semiconductor (PAS) which is a heat-treated product of an aromatic condensation polymer and has a polyacene skeleton structure having a hydrogen atom / carbon atom atomic ratio of 0.50 to 0.05 can also be used suitably. . Preferably, it is an electrode active material used for an electric double layer capacitor electrode.

  The electrode active material used for the negative electrode of the lithium ion capacitor electrode is a material that can reversibly carry lithium ions. Specifically, electrode active materials used in the negative electrode of lithium ion secondary batteries can be widely used. Preferred examples include crystalline carbon materials such as graphite and non-graphitizable carbon, and polyacene-based materials (PAS) described as the positive electrode active material. These carbon materials and PAS are obtained by carbonizing a phenol resin or the like, activated as necessary, and then pulverized.

  The shape of the electrode active material used for the lithium ion capacitor electrode is preferably a granulated particle. When the shape of the particles is spherical, a higher density electrode can be formed at the time of forming the electrode layer.

  The volume average particle diameter of the electrode active material used for the lithium ion capacitor electrode is usually 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 2 to 10 μm for both the positive electrode and the negative electrode.

  These electrode active materials can be used alone or in combination of two or more.

<Conductive agent>
The conductive agent used in the present invention is composed of an allotrope of particulate carbon having conductivity and no pores capable of forming an electric double layer, and improves the conductivity of the electrochemical element electrode. Specific examples include conductive carbon blacks such as furnace black, acetylene black, and ketjen black (registered trademark of Akzo Nobel Chemicals Bethloten Fennaut Shap). Among these, acetylene black and furnace black are preferable.

  The volume average particle diameter of the conductive agent used in the present invention is preferably smaller than the volume average particle diameter of the electrode active material, and the range thereof is usually 0.001 to 10 μm, preferably 0.05 to 5 μm, more preferably 0. 0.01 to 1 μm. When the volume average particle diameter of the conductive agent is within this range, high conductivity can be obtained with a smaller amount of use. These conductive agents can be used alone or in combination of two or more. The amount of the conductive agent is usually 0.1 to 50 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the amount of the conductive agent is within this range, the capacitance of the electrochemical device using the obtained electrochemical device electrode can be increased and the internal resistance can be decreased.

<Binder>
The binder used in the present invention is not particularly limited as long as it is a compound that can bind the electrode active material and the conductive agent to each other. A suitable binder is a dispersion type binder having a property of being dispersed in a solvent. Examples of the dispersion-type binder include polymer compounds such as fluorine-based polymers, diene-based polymers, acrylate-based polymers, polyimides, polyamides, polyurethane-based polymers, and fluorine-based polymers and diene-based polymers. Alternatively, an acrylate polymer is preferable, and a diene polymer or an acrylate polymer is more preferable in that the withstand voltage can be increased and the energy density of the electrochemical element can be increased.

  The diene polymer is a homopolymer of a conjugated diene or a copolymer obtained by polymerizing a monomer mixture containing a conjugated diene, or a hydrogenated product thereof. The proportion of the conjugated diene in the monomer mixture is usually 30% by weight or more, preferably 40% by weight or more, more preferably 50% by weight or more. Specific examples of the diene polymer include conjugated diene homopolymers such as polybutadiene and polyisoprene; aromatic vinyl / conjugated diene copolymers such as carboxy-modified styrene / butadiene copolymer (SBR); Copolymers of styrene / butadiene / methacrylic acid copolymer and aromatic vinyl / conjugated diene / carboxylic acid group-containing monomers such as styrene / butadiene / itaconic acid copolymer; acrylonitrile / butadiene copolymer (NBR) And vinyl cyanide / conjugated diene copolymers such as hydrogenated SBR and hydrogenated NBR.

Acrylate polymer of the general formula ^{_{(1): CH 2 = CR}} 1 -COOR 2 ( wherein, ^{R 1} represents a hydrogen atom or a methyl group, ^{R 2} represents an alkyl group or a cycloalkyl group.) Is represented by It is a polymer containing the monomer unit derived from a compound. Specific examples of the compound represented by the general formula (1) include ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-amyl acrylate, Acrylates such as isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, nonyl acrylate, lauryl acrylate, stearyl acrylate; ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n methacrylate -Butyl, isobutyl methacrylate, t-butyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isodecyl methacrylate, methacrylate Le lauryl, tridecyl methacrylate include methacrylates such as such as stearyl methacrylate. Among these, acrylate is preferable, and n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferable in that the strength of the obtained electrode can be improved. The ratio of the monomer unit derived from the compound represented by the general formula (1) in the acrylate polymer is usually 50% by weight or more, preferably 70% by weight or more. When an acrylate polymer in which the proportion of the monomer unit derived from the compound represented by the general formula (1) is within the above range is used, the heat resistance is high and the internal resistance of the obtained electrode for an electrochemical device is reduced. it can.

  As the acrylate polymer, a copolymerizable carboxylic acid group-containing monomer can be used in addition to the compound represented by the general formula (1). Specific examples include acrylic acid and methacrylic acid. Monobasic acid-containing monomers; dibasic acid-containing monomers such as maleic acid, fumaric acid, and itaconic acid. Among these, a dibasic acid-containing monomer is preferable, and itaconic acid is particularly preferable in terms of enhancing the binding property with the current collector and improving the electrode strength. These monobasic acid-containing monomers and dibasic acid-containing monomers can be used alone or in combination of two or more. The amount of the carboxylic acid group-containing monomer in the copolymerization is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts per 100 parts by weight of the compound represented by the general formula (1). Part by weight, more preferably in the range of 1 to 10 parts by weight. When the amount of the carboxylic acid group-containing monomer is within this range, the binding property with the current collector is excellent, and the obtained electrode strength is increased.

  In addition to the compound represented by the general formula (1), a copolymerizable nitrile group-containing monomer can be used for the acrylate polymer. Specific examples of the nitrile group-containing monomer include acrylonitrile, methacrylonitrile, and the like. Among them, acrylonitrile is preferable in that the binding strength with the current collector is increased and the electrode strength can be improved. The amount of acrylonitrile is usually 0.1 to 40 parts by weight, preferably 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the compound represented by the general formula (1). Range. When the amount of acrylonitrile is within this range, the binding property with the current collector is excellent, and the obtained electrode strength is increased.

  The binder is not particularly limited depending on its shape, but it has good binding properties, and can be prevented from being deteriorated due to a decrease in electrostatic capacity or repeated charge / discharge of the produced electrochemical element. Preferably there is. Examples of the particulate binder include those in which particles of a dispersion-type binder such as latex are dispersed in water, and powders obtained by drying such a dispersion.

  The glass transition temperature (Tg) of the binder used for this invention is -100-100 degreeC normally, Preferably it is -50-50 degreeC, Most preferably, it is -30-20 degreeC. When the glass transition temperature (Tg) of the binder is within this range, a small amount of use is excellent in binding properties to the current collector, and the strength of the electrode is increased.

  The number average particle size of the binder used in the present invention is not particularly limited, but is usually 0.0001 to 100 μm, preferably 0.001 to 10 μm, more preferably 0.01 to 1 μm. It is what has. When the number average particle diameter of the binder is within this range, an excellent binding force can be imparted to the polarizable electrode even with a small amount of use. Here, the number average particle diameter is a number average particle diameter calculated as an arithmetic average value obtained by measuring the diameter of 100 binder particles randomly selected in a transmission electron micrograph. The shape of the particles can be either spherical or irregular. These binders can be used alone or in combination of two or more. The amount of the binder is usually 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the amount of the binder is within this range, sufficient adhesion between the obtained electrode layer and the current collector can be ensured, the capacitance of the electrochemical element can be increased, and the internal resistance can be decreased.

<Dispersant>
The electrode composition used in the present invention preferably further contains a dispersant. The dispersant is used in a state of being dispersed or dissolved in the solvent of the electrode composition, and further has an action of uniformly dispersing the electrode active material, the conductive agent and the like in the solvent. For example, cellulosic polymers such as carboxymethylcellulose, methylcellulose, ethylcellulose and hydroxypropylcellulose, and ammonium salts or alkali metal salts thereof; poly (meth) acrylates such as sodium poly (meth) acrylate; polyvinyl alcohol, modified polyvinyl Examples include alcohol, polyethylene oxide; polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, and chitosan derivatives. These dispersants can be used alone or in combination of two or more. Among these, a cellulose polymer is preferable, and carboxymethyl cellulose or an ammonium salt or an alkali metal salt thereof is particularly preferable. Cellulosic polymers such as carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose, and ammonium salts or alkali metal salts thereof; polyacrylic acid (or methacrylic acid) salts such as sodium polyacrylic acid (or methacrylic acid); polyvinyl alcohol, Modified polyvinyl alcohol, polyethylene oxide; polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, chitosan derivatives and the like. Among these, a cellulose polymer is preferable, and carboxymethyl cellulose or an ammonium salt or an alkali metal salt thereof is particularly preferable.

  These dispersants can be used alone or in combination of two or more. The amount of the dispersant used is not particularly limited, but is usually 0.1 to 50 parts by weight, preferably 0.5 to 10 parts by weight, more preferably 0.8 to 100 parts by weight with respect to 100 parts by weight of the electrode active material. The range is 2 parts by weight. When the amount of the dispersant is within this range, it is possible to suppress sedimentation and aggregation of the solid content in the electrode composition.

<Other additives>
Examples of other additives include a surfactant. Examples of the surfactant include amphoteric surfactants such as anionic, cationic, nonionic, and nonionic anions. Among them, anionic or nonionic surfactants that are easily thermally decomposed are preferable.

  Surfactant can be used individually or in combination of 2 or more types. The amount of the surfactant is not particularly limited, but is 0 to 50 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the electrode active material. It is a range.

<Solvent>
Although it does not specifically limit as a solvent used in order to obtain an electrode composition, When using said dispersing agent, the solvent which can melt | dissolve a dispersing agent is used suitably. As a solvent capable of dissolving the dispersant, water is used, but an organic solvent may be used, or a mixed solvent of water and an organic solvent may be used. Examples of the organic solvent include alkyl alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol; alkyl ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane and diglyme; diethylformamide, dimethylacetamide and N-methyl- Amides such as 2-pyrrolidone (NMP) and dimethylimidazolidinone; sulfur solvents such as dimethyl sulfoxide and sulfolane; and the like. When a mixed solvent is used, the dispersibility of the binder or the solubility of the dispersant varies depending on the amount or type of the organic solvent. Thereby, the viscosity and fluidity | liquidity of an electrode composition can be adjusted. Among these, water is preferable as the solvent from the viewpoint of the working environment.

  In the production method of the present invention, the amount of the solvent used when preparing the electrode composition is such that the solid content concentration of the electrode composition is preferably 1% by weight or more, more preferably 10 to 50% by weight, in particular. The amount is preferably in the range of 20 to 30% by weight. When the solid content concentration is within this range, the binder is preferably dispersed uniformly, and the productivity is good in the step of spray drying the electrode composition described later.

  The viscosity of the electrode composition is usually 1 to 10,000 mPa · s, preferably 10 to 5,000 mPa · s, more preferably, under measurement conditions of 25 ° C. and 60 rpm using a B-type viscometer. It is in the range of 50 to 1,000 mPa · s. If the viscosity of the electrode composition is too high, granulation may be difficult, while if it is too low, the internal resistance of the electrochemical device tends to increase.

  The viscosity of the electrode composition can be appropriately controlled depending on the type and blending amount of the electrode active material, the binder and the dispersant to be used, and particularly when a cellulose polymer is used as the dispersant. By appropriately selecting the type, molecular weight, and blending amount of the cellulosic polymer, the viscosity of the electrode composition can be easily controlled within the above range. For example, when a high molecular weight cellulose polymer is used, the electrode composition viscosity increases, and when a low molecular weight cellulose polymer is used, the electrode composition viscosity decreases.

<Electrode composition preparation method>
An electrode composition is obtained by dispersing or dissolving an electrode active material, a conductive agent and a binder, a dispersing agent and other additives in a solvent. The method and procedure are not particularly limited. For example, an electrode active material, a conductive agent, a binder, a dispersant, and other additives are added to the solvent and mixed, and after the dispersant is dissolved in the solvent, the solvent is added to the solvent. A method of adding and mixing a dispersed binder (for example, latex) and finally adding and mixing an electrode active material and a conductive agent, or an electrode active material and a conductive agent in a binder dispersed in a solvent And a method of adding and mixing a dispersant dissolved in a solvent to the mixture. Examples of the mixing means include mixing equipment such as a ball mill, a sand mill, a bead mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, a homomixer, and a planetary mixer. Mixing is usually performed in the range of room temperature to 80 ° C. for 10 minutes to several hours.

(Step of spraying the electrode composition)
In the present invention, the electrode composition is sprayed for the purpose of making the electrode composition into droplets. By this operation, the effect of atomizing the electrode composition described later and applying a shock wave for the purpose of drying is further enhanced. Examples of the spraying method include a rotating disk method in which an electrode composition is introduced almost at the center of a disk rotating at high speed, and spraying is performed by centrifugal force of the disk, and a pressure method in which the electrode composition is pressurized and sprayed from a nozzle. . From the viewpoint that the apparatus can be miniaturized, spraying by pressurization (pressurization method) is preferable. The pressure type nozzle includes a one-fluid nozzle that sprays by liquid pressure and a two-fluid nozzle that pulverizes and sprays liquid with a high-speed airflow such as compressed air, but uses a two-fluid nozzle that facilitates atomization. It is more preferable. The compressed air pressure of the two-fluid nozzle is usually 0.01 to 5 MPa · s, preferably 0.05 to 1 MPa · s or less, more preferably 0.1 to 0.5 MPa · s.

(Process of applying shock wave)
In this invention, after spraying an electrode composition, a shock wave is provided to the sprayed electrode composition. A shock wave refers to a state in which pressure, density, temperature, and the like repeatedly rise and fall rapidly in a compressive fluid, and examples include sound waves, compression waves associated with explosions, and high-speed movement of objects. In particular, application of shock waves by sound waves is preferable from the viewpoints of economy and safety. When a shock wave is applied by sound waves, the electrode composition sprayed in advance is divided into further fine droplets and dried by physical shock characteristics for pulse operation including sound pressure and pressure.

In the present invention, the sound wave is preferably generated by pulse combustion gas. This is because the acoustic wave is generated by the pulse combustion gas, so that the electrode composition can be easily dried by the hot air of the combustion gas in addition to the physical impact. A pulse combustion gas is a combustion gas that pulsates in a certain cycle.
The pulsating cycle (hereinafter sometimes referred to as frequency) is usually 50 to 5,000 Hz, preferably 100 to 1000 Hz, more preferably 125 to 550 Hz. When the frequency is in this range, a sufficient drying effect can be obtained without causing vibration disturbance.
The pressure amplitude of the pulse combustion gas is preferably ± 0.1 kg / cm ² or more, more preferably ± 0.5 kg / cm ² or more, and further preferably ± 0.6 kg / cm ² or more. When the pressure amplitude is within this range, fine droplets can be generated efficiently.
The sound pressure of the pulse combustion gas is preferably 50 to 1000 decibels, more preferably 100 to 500 decibels, and further preferably 140 to 160 decibels. When the sound pressure is within this range, it is not necessary to take a great deal of soundproofing, so that fine droplets can be generated with good economic efficiency.

  The contact gas temperature of pulse combustion gas becomes like this. Preferably it is 50 degreeC or more, More preferably, it is 100-1000 degreeC, More preferably, it is 130-500 degreeC. When the contact gas temperature is less than 50 ° C., the particles tend not to be sufficiently dried. When the contact gas temperature exceeds 1,000 ° C., the particles tend to be easily modified by heat. The temperature of the electrode composition before being brought into contact with the pulse combustion gas is usually room temperature, but may be raised to room temperature or higher by heating.

(Composite particles for electrochemical device electrodes)
The composite particle for an electrochemical element electrode according to the present invention is obtained by the manufacturing method described above.

  The volume average particle size of the composite particles for electrochemical element electrodes is preferably in the range of 0.1 to 1,000 μm, more preferably 1 to 500 μm, and more preferably 5 to 30 μm. The volume average particle diameter can be measured using a laser diffraction particle size distribution measuring apparatus. By setting the volume average particle diameter of the composite particles within the above range, a uniform and dense thin-film electrode layer can be obtained by using an electrochemical element electrode forming material composed of small composite particles.

  The composite particle for an electrochemical element electrode suitable for the present invention has a particle size displacement rate of usually 5% or more, preferably 10 when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec by a micro compression tester. % Or more, more preferably 20 to 50%. The particle size displacement rate is the ratio (= ΔD / D0 × 100) of the amount of particle size reduction (ΔD = D0−D1) due to compression to the particle size D0 before compression of the composite particles. In addition, D1 is a value which changes according to a load amount with a particle size when applying a load.

  The composite particle for an electrochemical element electrode suitably used in the present invention has a particle size displacement rate per unit second when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec by a micro compression tester. The amount of change is preferably 50% or less, more preferably 10% or less, and particularly preferably 7% or less. The change amount of the particle size displacement rate per unit second is the change amount per unit second of the particle size change rate when the load increases at a load speed of 0.9 mN / sec. The particle size displacement rate when compressed to a maximum load of 9.8 mN measured by a micro-compression tester is a numerical value necessary to show the shape maintenance force of the composite particles. If the particle size displacement rate is too small, the composite particles are hardly deformed even by pressurization, so that the contact area between the particles is small and the conductivity is not increased. On the other hand, when the particle size displacement rate is too large, the composite particles are crushed, the network formed by the electrode active material and the conductive agent formed in the composite particles is broken, and the conductivity is lowered. Further, the change amount of the particle size displacement rate per unit second is an index for determining the presence or absence of crushing. When crushing occurs, the particle size decreases rapidly, so the amount of change in particle size displacement rate per unit second exceeds 25%. Since the composite particle having a particle size displacement rate of 5 to 70% when compressed to a maximum load of 9.8 mN has appropriate softness, the contact area between the particles is large. And since it does not crush, the network of an electrode active material and a electrically conductive agent is maintained.

  The composite particle for an electrochemical element electrode of the present invention can be subjected to post-treatment after particle production, if necessary. As specific examples, it is possible to remove the residual solvent, conversely, to add a small amount of solvent to the composite particles, or to add a binder.

(Electrodes for electrochemical devices)
An electrode for an electrochemical element according to the present invention is an electrode formed of a current collector and an electrochemical element electrode forming material comprising the composite particle for an electrochemical element electrode on at least one surface of the current collector. With layers. Each material and procedure are described in detail below.

<Electrode forming material>
The electrochemical element electrode forming material used in the present invention comprises the electrochemical element electrode composite particles. The electrode forming material may further contain an arbitrary substance. As an arbitrary substance, not only the substance contained in the above-mentioned electrode composition but also composite particles by various combinations thereof can be cited.

<Current collector>
Specifically, a metal, carbon, a conductive polymer, or the like can be used as the current collector used in the present invention. From the viewpoint of electrical conductivity, the current collector is preferably a metal. As the current collector metal, aluminum, platinum, nickel, tantalum, titanium, other alloys and the like are usually used. Among these, it is more preferable to use copper, aluminum, or an aluminum alloy in terms of conductivity and voltage resistance.

  The shape of the current collector is not particularly limited, but is in the form of a film or a sheet, and the sheet-like current collector may have pores. The sheet-like current collector may have a shape such as an expanded metal, a punching metal, or a net. When a sheet-like current collector having pores is used, the capacity per volume of the obtained electrode can be increased. When the sheet-like current collector has holes, the ratio of the holes is usually 1 area% or more, preferably 10 area% or more, more preferably 20 to 60 area%.

  The thickness of the current collector used in the present invention is usually 5 to 500 μm, preferably 10 to 100 μm, particularly preferably 20 to 50 μm. When the thickness of the current collector is in this range, the resistance of electron movement can be reduced, and the internal resistance can be reduced.

<Conductive adhesive layer>
The current collector used in the present invention may have a conductive adhesive layer formed on the surface thereof. The conductive adhesive layer is obtained by applying a conductive adhesive composition described in detail below onto a current collector and drying it. By using a current collector having a conductive adhesive layer, the current collector and the electrode layer are more firmly bonded, and the internal resistance of the electrochemical element is reduced.

  The conductive adhesive composition preferably contains a conductive assistant powder and a binder as essential components, and further contains a solvent, carboxymethylcellulose and / or a surfactant. Examples of the conductive assistant for the conductive adhesive composition include silver, nickel, gold, graphite, acetylene black, and ketjen black, and graphite and acetylene black are preferable. As the binder of the conductive adhesive composition, any of those exemplified as the binder used in the electrode layer of the present invention can be used. Moreover, water glass, an epoxy resin, a polyamideimide resin, a urethane resin, etc. can also be used, and each can be used individually or in combination of 2 or more types. The binder of the conductive adhesive composition is preferably an acrylate polymer, an ammonium salt or alkali metal salt of carboxymethyl cellulose, water glass, or a polyamideimide resin. The solvent of the conductive adhesive composition is preferably water. Moreover, as a dispersing agent of a conductive adhesive composition, the dispersing agent or surfactant which may be used for the electrode layer of the electrode of the said invention can be used.

  The method for producing the conductive adhesive composition used in the present invention is not particularly limited. Specifically, a ball mill, a sand mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, a planetary mixer, a Hobart mixer, and the like can be used.

  The method for forming the conductive adhesive layer used in the present invention is not particularly limited. For example, the conductive adhesive layer is formed on the current collector by the doctor blade method, dipping method, reverse roll method, direct roll method, gravure method, extrusion method, brushing, etc. .

  Examples of the method for drying the conductive adhesive layer include drying by hot air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams. Among these, from the viewpoint of high productivity and uniform productivity, a drying method by irradiation with far infrared rays is preferable. The drying temperature and the drying time are preferably a temperature and a time at which the solvent in the slurry applied on the current collector can be completely removed. The drying temperature is usually 25 ° C. or higher, preferably 50 to 500 ° C., more preferably 80 to 250. ° C. The drying time is usually 5 hours or less, preferably 1 second to 1 hour, more preferably 5 seconds to 30 minutes.

  The thickness of the conductive adhesive layer is usually 0.01 to 100 μm, preferably 0.1 to 50 μm, particularly preferably 1 to 20 μm. When the thickness of the conductive adhesive layer is in the above range, good adhesiveness can be obtained and the electron transfer resistance can be reduced.

<Electrode layer>
The electrode layer used in the present invention is formed from an electrochemical element electrode forming material containing the electrochemical element electrode composite particles.

<Method for forming electrode layer>
The electrode layer used in the present invention may be formed by forming an electrochemical element electrode forming material into a sheet shape, and then laminating the material on the current collector to form an electrode layer, or the electrochemical element electrode on the current collector The electrode layer may be formed by directly forming the forming material. Among these, from the viewpoint of productivity, it is preferable to form the electrode layer by directly forming the electrochemical element electrode forming material on the current collector. Hereinafter, a method for forming an electrode layer by directly forming an electrochemical element electrode forming material on a current collector will be described in detail.

  In the present invention, the electrochemical element electrode forming material is supplied onto at least one surface of the current collector. There is no restriction | limiting in particular in the method of supplying the formation material for electrochemical element electrodes on a collector. For example, a quantitative feeder that can quantitatively supply electrochemical element electrode forming materials may be used, or formation of a charged electrochemical element electrode on a grounded current collector such as electrostatic powder coating. The material may be supplied by spraying, or a charged electrochemical element electrode forming material may be transferred to a current collector installed as in electrostatic screen printing. Specific examples of the quantitative feeder include gravity feeders such as vibration feeders, table feeders, and rotary feeders, and mechanical force feeders such as screw feeders and belt feeders. Of these, the rotary feeder is preferred.

  Next, the current collector and the supplied electrochemical element electrode forming material are pressed with a pair of rolls to form an electrode layer on the current collector. In this step, the electrochemical element electrode forming material heated as necessary is formed into a sheet-like electrode layer by a pair of rolls. The temperature of the electrochemical element electrode forming material to be supplied is preferably 25 ° C. or higher, preferably 50 to 200 ° C., more preferably 70 to 140 ° C. When the electrochemical element electrode forming material in this temperature range is used, there is no slip of the electrochemical element electrode forming material on the surface of the roll, and the electrochemical element electrode forming material is continuously and uniformly supplied to the roll. Therefore, an electrode layer having a uniform film thickness and small variations in electrode density can be obtained.

  In the present invention, the temperature of the roll during molding is usually 0 to 200 ° C., preferably higher than the melting point or glass transition temperature of the binder, and 10 ° C. higher than the melting point or glass transition temperature of the binder. Is more preferable. When the roll is used, the molding speed is preferably larger than the viewpoint of productivity, and is usually 1 m / min or more, preferably 2 to 10 m / min, and more preferably 5 to 8 m / min. The press linear pressure between the rolls is not particularly defined, but is usually 0.01 to 100 kN / cm, preferably 0.1 to 50 kN / cm, more preferably 0 in that the electrode strength of the obtained electrode can be increased. 5 to 10 kN / cm.

  In the present invention, the arrangement of the pair of rolls is not particularly limited, but is preferably arranged substantially horizontally or substantially vertically. When arranged substantially horizontally, the current collector is continuously supplied between a pair of rolls, and an electrochemical element electrode forming material is supplied to at least one of the rolls. The electrode forming material is supplied to the gap, and the electrode layer can be formed by pressurization. In the case of disposing substantially vertically, the current collector is transported in the horizontal direction, an electrode forming material is supplied onto the current collector, and an electrode material layer is formed. After the supplied electrode material layer is leveled with a blade or the like as necessary, the current collector is supplied between a pair of rolls, and the electrode layer can be formed by pressurization.

  In order to eliminate variations in the thickness of the molded electrode layer, increase the density, and increase the capacity, further pressurization may be performed as necessary. The post-pressing method is generally a press process using a roll. In the pressing step, two cylindrical rolls are arranged vertically in parallel with a narrow interval, and each is rotated in the opposite direction, and the electrode is sandwiched and pressed between them. The temperature of the roll may be adjusted by heating or cooling. The temperature of the roll in the pressing step is usually 0 to 200 ° C, preferably higher than the melting point or glass transition temperature of the binder, and more preferably 10 ° C or higher than the melting point or glass transition temperature of the binder. The speed of the roll in the pressing step is preferably larger than the viewpoint of productivity, and is usually 1 m / min or more, preferably 2 to 10 m / min, and more preferably 5 to 8 m / min. Further, the press linear pressure between the rolls in the pressing step is not particularly defined, but is usually 0.01 to 100 kN / cm, preferably 0.1 to 50 kN / cm, in that the electrode strength of the obtained electrode can be increased. Preferably it is 0.5-10 kN / cm.

The density of the electrode layer obtained by the present invention is not particularly limited, but is usually 0.05 to 10 g / cm ³ , preferably 0.1 to 5.0 g / cm ³ , more preferably 0.40 to 3.0 g. / Cm ³ . Moreover, the thickness of an electrode layer is 1-1000 micrometers normally, Preferably it is 5-500 micrometers, More preferably, it is 10-400 micrometers.

(Electrochemical element)
The electrochemical device of the present invention includes the electrochemical device electrode obtained above. Examples of other components include a separator and an electrolytic solution.

  The separator is not particularly limited as long as it can insulate between the electrochemical element electrodes and allow cations and anions to pass therethrough. Specifically, polyolefins such as polyethylene and polypropylene, microporous membranes or nonwoven fabrics made of rayon or glass fiber, and porous membranes mainly made of pulp called electrolytic capacitor paper can be used. A separator is arrange | positioned between the electrodes for electrochemical elements so that said pair of electrode composition 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 1-500 micrometers, Preferably it is 10-100 micrometers, More preferably, it is 20-60 micrometers.

The electrolytic solution is usually composed of an electrolyte and a solvent. As the cation, (1) imidazolium, (2) quaternary ammonium, (3) quaternary phosphonium, (4) lithium ion, and the like as shown below can be used as the cation.
(1) Imidazolium 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1,3-diethylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4-tetramethyl Imidazolium, 1,3,4-trimethyl-ethylimidazolium, 1,3-dimethyl-2,4-diethylimidazolium, 1,2-dimethyl-3,4-diethylimidazolium, 1-methyl-2,3 , 4-triethylmethylimidazolium, 1,2,3,4-tetraethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1,2,3- Triethylimidazolium, etc. (2) Quaternary ammonium tetramethylammonium, ethyltrimethylammonium, diethyldi (3) Quaternary phosphonium tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, methyltriethylphosphonium, methyltributylphosphonium, dimethyldiethylphosphonium, etc. ( 4) Lithium ion

Similarly, the electrolyte has PF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , N (RfSO ₃ ) ²⁻ , C (RfSO ₃ ) ³⁻ , RfSO ₃ ⁻ (where Rf is the number of carbon atoms). 1 to 12 fluoroalkyl groups), F ⁻ , ClO ₄ ⁻ , AlCl ₄ ⁻ , AlF ₄ ^{− and the} like can be used. These electrolytes can be used alone or in combination of two or more.

  The solvent of the electrolytic solution is not particularly limited as long as it is generally used as a solvent for the electrolytic solution. Specifically, carbonates such as propylene car boat, ethylene carbonate and butylene carbonate; lactones such as γ-butyrolactone; sulfolanes; nitriles such as acetonitrile; These solvents can be used alone or as a mixed solvent of two or more. Of these, carbonates are preferable.

  An electrochemical element is obtained by impregnating the above-mentioned element with an electrolytic solution. Specifically, the device can be manufactured by winding, laminating, or folding the device in a container as necessary, and pouring the electrolyte into the container and sealing it. Further, a device in which an element is previously impregnated with an electrolytic solution may be stored in a container. Any known container such as a coin shape, a cylindrical shape, or a square shape can be used as the container.

  The electrochemical element electrode of the present invention can be suitably used as an electric double layer capacitor electrode or a lithium ion capacitor electrode.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples. In the examples and comparative examples, “part” and “%” are based on weight unless otherwise specified. Each characteristic in an Example and a comparative example is measured in accordance with the following method.

(Measurement of volume average particle diameter)
The volume average particle size of the composite particles for electrochemical device electrodes was measured using a laser diffraction particle size distribution analyzer (SALD-2000: manufactured by Shimadzu Corporation).

(Measurement of moisture content)
The water content of the composite particles for electrochemical device electrodes was measured from the weight difference before and after drying at 150 ° C. and normal pressure.

(Measurement of internal resistance)
The produced coin cell-shaped electric double layer capacitor was allowed to stand for 24 hours, and then charged and discharged for measurement. Charging is started at a constant current of 10 mA. When the voltage reaches 2.7 V, the voltage is maintained and constant voltage charging is performed, and the charging is completed when the charging current is reduced to 0.5 mA. Next, discharging was performed at a constant current of 10 mA immediately after the end of charging, and the internal resistance was calculated from the voltage drop 0.1 seconds after the discharge and the constant current value. In addition, let internal resistance value be a relative value when the internal resistance value of the electric double layer capacitor produced using the electrode of the comparative example 1 is set to 100%. A smaller internal resistance value is preferable.

Example 1
<Preparation of composite particles for electrochemical device electrodes>
100 parts of an electrode active material (activated carbon with a specific surface area of 2000 m ² / g and a weight average particle size of 5 μm), 5 parts of a conductive agent (acetylene black “Denka Black powder”: manufactured by Denki Kagaku Kogyo Co., Ltd.), a dispersion-type binder (number 40% aqueous dispersion of a cross-linked acrylate polymer having an average particle size of 0.15 μm and a glass transition temperature of −40 ° C .: 25 parts of “AD211” manufactured by Nippon Zeon Co., Ltd., dispersant (1.5% aqueous solution of carboxymethyl cellulose) “DN-800H”: manufactured by Daicel Chemical Industries, Ltd.) 133.3 parts, dispersant (1.5% aqueous solution of carboxymethyl cellulose “DN-10L”: manufactured by Daicel Chemical Industries, Ltd.) 66.7 parts and ion-exchanged water were all added. It was supplied so that the solid content concentration would be 20% and mixed by a planetary mixer to prepare an electrode composition having a viscosity of 374 mPa · s. Next, using a high pulcon small demo machine (made by Okawara Chemical Co., Ltd.) equipped with a two-fluid nozzle pressure spraying device and a pulse combustion device, the compression air pressure of the two-fluid nozzle is 0.2 MPa · s, the frequency of the pulse combustion gas is 550 Hz, the pressure The electrode composition was sprayed and dried under the conditions of an amplitude of ± 0.8 kg / cm ² , a sound pressure of 145 decibels, and a contact gas temperature of 280 ° C. to obtain composite particles for electrochemical device electrodes. Table 1 shows the volume average particle diameter and water content of the obtained composite particles for electrochemical device electrodes.

<Production of electrochemical element electrode>
A roll for press (roll temperature 120 ° C., press) of a roll press machine (pressed rough surface heat roll; manufactured by Hirano Giken Kogyo Co., Ltd.) using a quantitative feeder (Nikka Corporation, Nikka Spray K-V) at a supply rate of 15 g / min. (Compound particle for electrochemical device electrode) produced above is supplied to a linear pressure of 4 kN / cm). An aluminum foil having a width of 100 mm and a thickness of 30 μm is inserted between press rolls, and the composite particles for electrochemical element electrodes supplied from a quantitative feeder are adhered to one side of a plain aluminum foil as a current collector, and a molding speed of 5 m / Press molded in minutes. Then, it post-pressurized at the speed | rate of 5 m / min using the said roll press machine (roll temperature 120 degreeC, press linear pressure 4kN / cm). As a result, an electric double layer capacitor electrode having an electrode layer with an average thickness of 60 μm was obtained.

<Production of electrochemical device>
The electric double layer capacitor electrode obtained above was impregnated with an electrolytic solution (1.0 mol / L of propylene carbonate solution of tetraethylammonium fluoroborate) at room temperature for 1 hour, and then the two electrodes were electroded through a cellulose separator. The coin cell-shaped electric double layer capacitor was manufactured by arranging the electrodes so that the electrodes face each other and the electrodes are not in electrical contact with each other. The internal resistance of this electric double layer capacitor was measured. The results are shown in Table 1.

(Example 2)
In Example 1, except that ion-exchanged water was supplied so that the total solid concentration of the electrode composition was 15%, in the same manner as in Example 1, composite particles for electrochemical element electrodes, electric double layer capacitor electrode And an electric double layer capacitor was obtained. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, except that the electrode composition was spray-dried by a rotating disk method with hot air at 150 ° C. using a spray dryer (with a pin type atomizer manufactured by Okawara Chemical Industries Co., Ltd.), the same as in Example 1 A composite particle for a chemical element electrode, an electric double layer capacitor electrode, and an electric double layer capacitor were obtained. The results are shown in Table 1.

(Comparative Example 2)
In Comparative Example 1, except that ion-exchanged water was supplied so that the total solid concentration of the electrode composition was 15%, the composite particle for electrochemical element electrode and the electric double layer capacitor electrode were the same as Comparative Example 1 And an electric double layer capacitor was obtained. The results are shown in Table 1.

  As described above, as shown in Table 1, according to the production method of the present invention, after spraying an electrode composition obtained by dispersing or dissolving an electrode composition such as an electrode active material, a conductive agent and a binder in a solvent. By applying a shock wave, it was possible to efficiently obtain composite particles for electrochemical device electrodes having a small volume average particle diameter even when the solid content concentration of the electrode composition was high. On the other hand, in the comparative example in which the shock wave is not applied after spraying the electrode composition, in order to obtain composite particles having a volume average particle diameter equivalent to that of the example, the solid content concentration is set as in comparative example 2. It is necessary to make it 15% or less. Although not described in the examples, similar results were obtained with lithium ion capacitors.

  The manufacturing method of the composite particle for electrochemical element electrodes of this invention can be used suitably for manufacture of an electrochemical element electrode.

Claims (11)

  A method for producing composite particles for electrochemical element electrodes, characterized by spraying an electrode composition comprising an electrode active material, a conductive agent, a binder and a solvent, and then applying a shock wave to the sprayed electrode composition .   The method for producing composite particles for an electrochemical element electrode according to claim 1, wherein the shock wave is a sound wave.   The method for producing composite particles for an electrochemical element electrode according to claim 2, wherein the sound wave is generated by a pulse combustion gas.   The method for producing composite particles for an electrochemical element electrode according to any one of claims 1 to 3, wherein the spray of the electrode composition is spraying by pressurization.   The manufacturing method of the composite particle for electrochemical element electrodes in any one of Claims 1-4 whose solid content concentration of the said electrode composition is 1 weight% or more.   Electrochemical element electrode composite particles obtained by the production method according to claim 1.   The composite particle for an electrochemical element electrode according to claim 6, wherein the volume average particle diameter is 0.1 to 1,000 μm.   A material for forming an electrochemical element electrode, comprising the composite particle for an electrochemical element electrode according to claim 6 or 7.   An electrochemical element electrode comprising a current collector and an electrode layer formed on at least one surface of the current collector from the electrochemical element electrode forming material according to claim 8.   The electrochemical device electrode according to claim 9, which is used for an electric double layer capacitor.   The electrochemical device electrode according to claim 9, which is for a lithium ion capacitor.