JP2010278125A - Method of manufacturing electrode for electrochemical element, and electrochemical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of stably manufacturing an electrode for an electrochemical element of low internal resistance with high coating efficiency. <P>SOLUTION: The present invention relates to: the method of manufacturing the electrode for the electrochemical element characterized by forming an electrode layer by supplying an electrode material charged by triboelectrification onto at least one surface of a current collector; and the electrochemical element obtained by the method. The triboelectrification is preferably electrostatic charging by friction between the electrode material and a substance containing a fluorine-containing group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrode for an electrochemical element and a method for producing the electrochemical element. More specifically, the present invention relates to a manufacturing method for manufacturing an electrode for an electrochemical element having a thin and uniform electrode thickness and capable of reducing internal resistance with high productivity.

  Lithium ion secondary batteries and electric double layer capacitors are expected to be used as large power sources such as distributed power sources and hybrid vehicles due to environmental problems and resource problems of energy. However, in order to apply these electrochemical elements as a large power source, it is desired to reduce internal resistance in order to reduce energy loss during large current discharge.

  In order to reduce internal resistance, it is generally performed to make the electrode thickness thin and uniform, and it is required to manufacture a thin film electrode with high productivity.

  As an electrode manufacturing method, an electrode material containing an electrode active material and a binder is made into a slurry, applied and dried; a method in which an electrode material is kneaded and a roll is rolled to a target thickness; an electrode material Or the like, or a method of pressure molding in the form of composite particles. Among these, the method of pressure-molding the electrode material is preferable in terms of productivity, and various methods for supplying the electrode material have been proposed.

  As a method for supplying the electrode material, there is a method in which the electrode material is charged and electrostatically attached. This method is excellent in productivity because the electrode material can be supplied thinly and evenly, and the electrode material that has not adhered can be recovered and reused.

  Examples of the method for electrostatically charging the electrode material include a method for charging the electrode material by friction, and a method for charging by directly applying a voltage to the electrode material using corona discharge.

For example, in Patent Document 1, an electrode powder material charged by frictional charging between iron powder and an electrode powder material is supplied onto a photosensitive drum, and the electrode powder material on the photosensitive drum is thin paper or A method for forming an electrode by electrostatic transfer onto a substrate made of an organic fiber material is disclosed. According to this method, an extremely thin solid activated carbon electrode can be stably manufactured.
Patent Document 2 discloses a spraying step of spraying electrode raw material powder on a transport path that runs in the horizontal direction, a current collector supplying step of supplying a current collector onto the sprayed electrode raw material powder, There is disclosed a method for producing an electrode for an electrochemical device, comprising a zone pressure bonding step of continuously pressing an electrode raw material powder and a current collector to form an electrode. And as a method of supplying electrode raw material powder, the method of making it adhere by static electricity, such as an electrostatic spraying method, is illustrated. According to this method, an electrode sheet having high uniformity and sufficient performance can be continuously produced at a high speed.
Patent Document 3 is characterized in that an electrode layer is formed by charging a mixed powder composed of an active material, a conductive material, and a binder with an electric field application electrode and supplying the mixture onto a current collector. An electrode manufacturing method is disclosed. According to this method, it is said that an electrode that is easier to control, has better productivity, and has better load characteristics than the wet method can be obtained.

JP 2001-223142 A International Publication No. 2005/117043 JP 2001-351616 A

As a problem for manufacturing a thin film electrode with high productivity, it is required to continuously supply a stable electrode material. For such a problem, a method of electrostatically supplying an electrode material is effective. However, although there is a possibility of recovery and reuse, improvement of the coating efficiency when the electrode material is supplied electrostatically is also important in terms of productivity. For such a problem, in the method described in Patent Document 1, an electrode powder material charged by frictional charging between iron powder and an electrode powder material is supplied onto a photosensitive drum and then charged. Since there are a plurality of steps of transferring the electrode powder raw material onto the substrate, there is a problem that the coating efficiency cannot be sufficiently increased. Even with the electrostatic spraying method as described in Patent Document 2, the coating efficiency is also low. There was a problem that could not be high enough.
Further, in the method of charging by directly applying a voltage to the electrode material by corona discharge as in Patent Document 3, the electrode material is forcibly charged, and thus there is an advantage that the material is not limited. There are phenomena peculiar to corona discharge, such as reverse ionization, and the problem is that the end of the electrode is thick, the electrode is easily cracked and chipped, and the internal resistance is high.
Accordingly, an object of the present invention is to provide a method for producing an electrode for an electrochemical element that has a high coating efficiency and has a low internal resistance.

  As a result of earnest study on the above problems, the present inventor supplies an electrode material electrostatically charged by frictional charging to at least one surface on a current collector to form an electrode layer, thereby forming an electrode Since the material can be charged efficiently, the electrode material can be efficiently supplied onto the current collector, and it has been found that it is possible to manufacture an electrode for an electrochemical element having a low internal resistance stably for a long time. Based on these findings, the inventors have completed the following present invention.

Thus, according to the present invention, there is provided a method for producing an electrode for an electrochemical element, wherein an electrode layer is formed by supplying an electrode material charged by frictional charging onto at least one surface of a current collector. Is done.
Moreover, according to this invention, the electrochemical element formed using the electrode for electrochemical elements obtained by the said manufacturing method is provided.

  According to the present invention, since the electrode material can be charged efficiently, the electrode material can be efficiently supplied onto the current collector stably for a long time, and the electrode for an electrochemical device having a low internal resistance. Can be manufactured with high productivity. The present invention can be suitably used particularly as a method for producing an electrode for an electric double layer capacitor, an electrode for a hybrid capacitor, and an electrode for a lithium ion secondary battery.

  The method for producing an electrode for an electrochemical element of the present invention is characterized in that an electrode layer is formed by supplying an electrode material charged by frictional charging onto at least one surface of a current collector.

<Friction charging>
In the present invention, as a method of triboelectrically charging the electrode material, a method is used in which the electrode material and a substance that easily charges the electrode material are brought into contact with each other using a charging train. The charged column is inherent to a material, and has a relative order of easiness of charging from a material that is easily charged negatively to a material that is easily charged positively. The more the two substances to be rubbed are apart from each other on the charged column, the more charged each becomes. Therefore, on the charged column, the electrode material can easily be brought into contact with the substance separated from the electrode material by the electrode material. Can be charged. When the electrode material is charged positively, it is brought into contact with polytetrafluoroethylene or vinyl chloride. When the electrode material is charged negatively, the electrode material is brought into contact with asbestos or nylon. Thus, each can be charged.

  The substance to be rubbed with the electrode material preferably has a fluorine-containing group. The substance having a fluorine-containing group is preferably a fluorocarbon, and among the fluorocarbons, a fluorocarbon polymer is more preferred, and polytetrafluoroethylene and polyvinylidene fluoride are particularly preferred. If a substance having a fluorine-containing group is used as a substance to be rubbed with the electrode material, the surface energy of the substance to be rubbed will be reduced, and the electrode material will be less likely to adhere to the surface of the substance to be rubbed, causing stable tribocharging for a long time It becomes possible. If the electrode material adheres to the substance to be rubbed with the electrode material, the substance to be rubbed with the electrode material and the electrode material are difficult to contact, and the electrode material cannot be stably applied. As the substance having a fluorine-containing group, in addition to the fluorocarbon, a metal having a fluorocarbon coated on the surface can be used.

  The chargeability of the substance can be adjusted by adding a functional group. Examples of the functional group that charges the substance more positively include an amino group and an amide group. Examples of the functional group that charges the substance more negatively include a fluorine-containing group, a nitro group, and a chlorine-containing group. If the method of charging the electrode material is triboelectric charging with polytetrafluoroethylene, adding a functional group that is positively charged by the electrode material can increase the charge amount and improve the coating efficiency. it can.

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

  The shape of the current collector used in the present invention is not particularly limited, but is in the form of a film or a sheet, and the sheet-like current collector may have pores. Further, 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 preferably 10 to 79 area%, more preferably 20 to 60 area%.

  Although the thickness of a collector is suitably selected according to the intended purpose, it is 1-200 micrometers normally, Preferably it is 5-100 micrometers, More preferably, it is 10-50 micrometers. When the thickness of the current collector is within this range, the resistance of electron movement can be reduced, and the internal resistance can be reduced.

In the present invention, an adhesive layer is preferably formed on at least one surface of the current collector. The adhesive layer is more preferably conductive because it can reduce the interface resistance between the electrode layer and the current collector. The adhesive layer can be formed by applying and drying an adhesive on the surface of the current collector.
The adhesive is obtained by dispersing a conductive assistant powder, a binder, and a dispersant added as necessary in water or an organic solvent. Examples of the conductive assistant used in the conductive adhesive include silver, nickel, gold, graphite, acetylene black, and ketjen black, and graphite and acetylene black are preferable. As the binder used for the conductive adhesive, any of those exemplified as the binder constituting the electrode layer described later can be used. Moreover, water glass, an epoxy resin, a polyamide-imide resin, a urethane resin, etc. can also be used, and these can be used individually or in combination of 2 or more types, respectively. As the binder used for the conductive adhesive, an acrylate polymer, an ammonium salt or alkali metal salt of carboxymethyl cellulose, water glass, and a polyamideimide resin are preferable. Moreover, as a dispersing agent used for an electroconductive adhesive agent, the dispersing agent or surfactant which may be used for the electrode layer of the manufacturing method of the said invention can be used.
The method for forming the adhesive layer used in the present invention is not particularly limited. For example, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating, an electrostatic coating method, etc. Is formed on the current collector.

  The thickness of the adhesive layer is usually 0.01 to 20 μm, preferably 0.1 to 10 μm, particularly preferably 1 to 5 μm. When the thickness of the adhesive layer is within the above range, the internal resistance of the electrochemical device having the electrochemical device electrode obtained by the production method of the present invention can be further reduced.

  The electrode material used in the present invention refers to an electrode active material, a conductive auxiliary agent, a binder, and other materials necessary for constituting an electrode, which are usually in the form of solid particles. .

(Electrode active material)
What is necessary is just to select the electrode active material used for the electrode for electrochemical elements obtained by the manufacturing method of this invention according to the electrochemical element in which an electrode is utilized.

  When the electrode for an electrochemical element obtained by the production method of the present invention is used for an electrode for an electric double layer capacitor or a positive electrode for a hybrid capacitor, an allotrope of carbon is usually used as the electrode active material. 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.

When the electrode for an electrochemical element obtained by the production method of the present invention is used as a positive electrode for a lithium ion secondary battery, specifically, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO _{4 4} , lithium-containing composite metal oxides such as LiFeVO ₄ ; transition metal sulfides such as TiS ₂ , TiS ₃ , and amorphous MoS ₃ ; Cu ₂ V ₂ O ₃ , amorphous V ₂ O · P ₂ O ₅ , Transition metal oxides such as MoO ₃ , V ₂ O ₅ , V ₆ O ₁₃ are exemplified. Furthermore, conductive polymers such as polyacetylene and poly-p-phenylene are listed. Preferred is a lithium-containing composite metal oxide.

  When the electrode for an electrochemical element obtained by the production method of the present invention is used for a negative electrode for a lithium ion secondary battery or a negative electrode for a hybrid capacitor, the electrode active material may be amorphous carbon, graphite, natural graphite. , Mesocarbon microbeads (MCMB), and carbonaceous materials such as pitch-based carbon fibers; conductive polymers such as polyacene; Si, Sn, Sb, Al, Zn, and W that can be alloyed with lithium. Crystalline carbonaceous materials such as graphite, natural graphite, and mesocarbon microbeads (MCMB) are preferable.

  The volume average particle diameter of the electrode active material used in the present invention is usually 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 3 to 20 μm.

The specific surface area of the electrode active material used in the present invention, ^{30 m} 2 / g or more, preferably preferably 500~5,000m 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. Moreover, these electrode active materials can be used individually or in combination of 2 or more types.

(Conductive aid)
The conductive auxiliary agent used in the present invention is composed of an allotrope of particulate carbon that has conductivity and does not have pores that can form an electric double layer, and specifically includes furnace black, acetylene black, and kettle. Examples thereof include conductive carbon black such as chain black (registered trademark of Akzo Nobel Chemicals Besloten Fennaut Shap). Among these, acetylene black and furnace black are preferable.

  The volume average particle diameter of the conductive auxiliary 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. 0.01 to 1 μm. When the volume average particle diameter of the conductive additive is within this range, high conductivity can be obtained with a smaller amount of use. These conductive assistants can be used alone or in combination of two or more. The amount of the conductive assistant is usually 0.1 to 50 parts by weight, preferably 0.5 to 15 parts by weight, 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 additive is within this range, the capacity 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 additive to each other. Examples of the type include fluorine-based polymers, diene-based polymers, acrylate-based polymers, and cellulose-based polymers. Among these, a diene polymer, an acrylate polymer, or a cellulose polymer is preferable, and the diene polymer or the acrylate polymer can increase the withstand voltage and increase the energy density of the electrochemical device. It is more preferable at the point which can be performed. In addition, when the method of charging the electrode material is frictional charging with a substance having a fluorine-containing group, the charge amount described later can be adjusted by utilizing the relationship of the charge train. For example, an acrylate polymer is preferable in that the charge amount can be increased because it is easier to be positively charged on a charged column than a diene polymer.

  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, meta Lauryl acrylic acid, 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.

  In addition to the compound represented by the general formula (1), a copolymerizable carboxylic acid group-containing monomer can be used for the acrylate polymer. Specific examples of the carboxylic acid group-containing monomer include monobasic acid-containing monomers such as acrylic acid and methacrylic acid; 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 in the copolymerization is usually 0.1 to 40 parts by weight, preferably 0.5 to 30 parts by weight, more preferably 100 parts by weight of the compound represented by the general formula (1). It is in the range of 1 to 20 parts by weight. 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 acrylate polymer may be a copolymer obtained by copolymerizing an alkyl styrene monomer or vinyl ester in addition to the monomer. Examples of alkyl styrene monomers include alkyl styrene monomers such as styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene and octyl styrene. The Vinyl esters include vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl persate, vinyl laurate, vinyl stearate, vinyl benzoate, pt -Vinyl esters such as vinyl butyl benzoate and vinyl salicylate can be mentioned.

For the diene polymer and acrylate polymer, in addition to the monomer constituting the main component of each polymer, an amino group-containing monomer or an amide group-containing monomer copolymerizable with these is used. Can do. Specific examples of the amino group-containing monomer include diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminomethyl methacrylate. Specific examples of the amide group-containing monomer include methacrylamide, diacetone acrylamide, and acrylamide-2- Examples include methyl propane sulfonic acid, acrylamide, N-methylol acrylamide, and diethylaminomethyl methacrylate. Among these, amino group-containing monomers are preferable, and diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminomethyl methacrylate are more preferable from the viewpoint that the charge amount of the electrode material described later can be increased.
The amount of the amino group-containing monomer and the amide group-containing monomer in the copolymerization constitutes the monomer (conjugated diene) constituting the main component of the diene polymer or the main component of the acrylic polymer. Preferably in the range of 1 to 90 parts by weight, more preferably 5 to 70 parts by weight, particularly preferably 10 to 60 parts by weight per 100 parts by weight of the monomer (compound represented by the general formula (1)) It is. When the amount of the amino group-containing monomer and the amide group-containing monomer is within the above range, the charge amount of the electrode material can be increased, and the coating efficiency can be further improved and the productivity can be further increased. it can.

  The cellulose polymer is cellulose in which part or all of the hydroxyl groups of cellulose are substituted, and specific examples include nitrocellulose, acetylcellulose, and cellulose ether. Among these, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose, and cellulose ethers such as ammonium salts or alkali metal salts thereof are preferred, and carboxymethylcellulose or ammonium salts or alkali metal salts thereof have binding properties with the current collector. It is more preferable in that the electrode strength can be improved. In addition, an ammonium salt of carboxymethyl cellulose is particularly preferable in that the charge amount of the electrode material can be increased.

  The amount of the binder used in the present invention is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. Range. When the amount of the binder is in the above range, sufficient adhesion between the obtained electrode layer and the current collector can be secured, the capacity of the electrochemical device can be increased, and the internal resistance can be decreased. Further, when the amount of the binder is increased, the charge amount of the electrode material described later can be increased, and when the amount of the binder is decreased, the charge amount of the electrode material can be decreased.

  In the manufacturing method of this invention, the following materials required in order to comprise an electrode may be contained.

(Dispersant etc.)
The dispersant is used by being dissolved in a slurry solvent, which will be described later, and uniformly dispersing the electrode active material, the conductive auxiliary agent, and the like in the solvent. Specific examples of the dispersant include 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 alcohol, polyethylene oxide; polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, chitosan derivatives and the like. 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.

  The amount of the dispersant used can be used within a range that does not impair the effects of the present invention, and is not particularly limited, but is usually 0.1 to 10 parts by weight, preferably 100 parts by weight, preferably It is 0.5-5 weight part, More preferably, it is the range of 1-4 weight part. By using a dispersing agent, sedimentation and aggregation of solid content in the slurry can be suppressed. Moreover, since the clogging of the atomizer at the time of spray drying can be prevented, spray drying can be performed stably and continuously.

  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.

  The electrode material used in the present invention includes the above-described electrode active material, and has a particle shape formed by containing a conductive additive and a binder as suitable components, and if necessary, a dispersant and other additives ( Hereinafter, it may be referred to as “composite particle”. When the electrode material is composite particles, the electrode strength of the obtained electrode for an electrochemical element can be further increased, and the internal resistance can be further reduced.

The production method of the composite particles is not particularly limited, and is a spray drying granulation method, a rolling bed granulation method, a compression granulation method, a stirring granulation method, an extrusion granulation method, a crushing granulation method, a fluidized bed granulation method. It can be produced by a known granulation method such as a granulation method, a fluidized bed multifunctional granulation method, or a melt granulation method. Among these, the spray-drying granulation method is preferable because composite particles in which the binder and the conductive auxiliary agent are unevenly distributed near the surface can be easily obtained.
The spray-drying granulation method includes a step of mixing an electrode active material, a binder, and, if necessary, a dispersant, a conductive additive and other components in a solvent to form a dispersion, and the dispersion Spray drying to form composite particles. Specifically, in the composite particle forming step, the dispersion liquid is sprayed from an atomizer using a spray dryer, and the sprayed dispersion liquid is dried inside a drying tower, whereby an electrode contained in the dispersion liquid Spherical composite particles composed of an active material, a binder, and other components are formed. When composite particles obtained by the spray drying granulation method are used, the electrode for an electrochemical element of the present invention can be obtained with high productivity. In addition, the internal resistance of the electrode can be further reduced.

  In the case of producing composite particles by spray drying granulation, the solvent used for obtaining the dispersion is not particularly limited, but a solvent capable of dissolving the dispersant is preferably used. 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. 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 and dimethylimidazolidinone; Sulfur solvents such as dimethyl sulfoxide and sulfolane; Among these, alcohols are preferable as the organic solvent. When water and an organic solvent having a lower boiling point than water are used in combination, the drying rate can be increased during spray drying. Further, the dispersibility of the binder or the solubility of the dispersant varies depending on the amount or type of the organic solvent used in combination with water. Thereby, the viscosity and fluidity | liquidity of a slurry can be adjusted and production efficiency can be improved.

  The weight average particle diameter of the composite particles suitably used in the present invention is usually in the range of 0.1 to 1,000 μm, preferably 5 to 500 μm, more preferably 10 to 100 μm. When the weight average particle diameter of the composite particles is within this range, the composite particles are less prone to agglomerate, and electrostatic force against gravity is increased, which is preferable. The weight average particle diameter can be measured using a laser diffraction particle size distribution measuring apparatus.

(Charge control agent)
In the present invention, it is preferable that the electrode material further contains a charge control agent. When the electrode material further contains a charge control agent, an electrode material with stable chargeability can be obtained, and an electrode can be manufactured stably for a long period of time.
In the present invention, the charge control agent is a substance that is used by being added to the electrode material and has a function of improving the charge amount of the electrode material.
The charge control agent used in the present invention includes fine particles having a particle size smaller than that of the electrode material; a positive charge control agent having an action of positively improving the charge amount; a negative charge control agent having an action of negatively improving the charge amount Is mentioned. Among these, when the method of charging the electrode material is triboelectric charging with a substance having a fluorine-containing group, the positive charge control has a function of positively improving fine particles having a smaller particle diameter than the electrode material and the charge amount. An agent is preferable in that the charge amount of the electrode material can be improved.

  Examples of the fine particles having a particle size smaller than that of the electrode material include inorganic particles and organic resin particles. Examples of the inorganic particles include silicon dioxide, aluminum oxide, titanium oxide, zinc oxide, tin oxide, barium titanate, and strontium titanate. The average particle diameter of the inorganic particles is preferably 5 to 100 nm, more preferably 7 to 50 nm. The organic resin particles include methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles, zinc stearate, calcium stearate, and shells that are methacrylic. Examples thereof include core-shell type particles having an acid ester copolymer and a core formed of a styrene polymer. The average particle diameter of the organic particles is preferably 20 to 800 nm, more preferably 100 to 500 nm. Among these, silicon dioxide particles and styrene-methacrylic acid ester copolymer particles are particularly preferable in that they have an effect of improving the fluidity of the electrode material. Further, these fine particles can be used after the surface thereof is hydrophobized, and the hydrophobized silicon dioxide particles are particularly suitable in that the amount of change in charge amount with respect to humidity is small. The fine particles may be used alone or in combination of two or more. When two or more kinds of fine particles are used in combination, a method of combining inorganic particles having different average particle diameters or combining inorganic particles and organic resin particles is preferable.

Examples of the positive charge control agent having an action of positively improving the charge amount include nigrosine dyes, triphenylmethane dyes, quaternary ammonium salts, resins containing quaternary ammonium groups and / or amino groups, or inorganic particles. Can be mentioned.
Examples of the negative charge control agent having an action to negatively improve the charge amount include trimethylethane dyes, metal complex salts of salicylic acid, metal complex salts of benzyl acid, copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex azo dyes, Examples include heavy metal-containing acidic dyes such as azochrome complexes, calixarene type phenolic condensates, cyclic polysaccharides, resins containing carboxyl groups and / or sulfonyl groups, and the like.
When the method of charging the electrode material is frictional charging with a substance having a fluorine-containing group, the substance having a fluorine-containing group tends to be negatively charged, so by adding a positive charge control agent to the electrode material, The charge amount of the electrode material can be increased, and the coating efficiency can be improved.

The content of the charge control agent is not particularly limited, but is preferably 0.01 to 20% by weight, particularly preferably 0.1 to 10% by weight, based on the electrode material. When the amount of the charge control agent is in the above range, the charge amount of the electrode material can be improved, and the coating efficiency can be improved.
The method for containing the charge control agent is not particularly limited, and is a method in which the charge control agent and another electrode material are charged into a mixer such as a Henschel mixer and stirred; composite particles are produced by spray drying granulation. In some cases, a method of dissolving or dispersing the charge control agent in the dispersion liquid, and the like, among others, a method of charging the charge control agent and another electrode material in a mixer such as a Henschel mixer and stirring is preferable, More preferably, the composite particles and the charge control agent are charged into a mixer such as a Henschel mixer and stirred. As a method of incorporating the charge control agent, the charge control agent can be attached to the surface of the composite particles by using a method in which the composite particles and the charge control agent are charged into a mixer such as a Henschel mixer and stirred.

In the present invention, the electrode material preferably has a functional group that is easily positively charged. When the electrode material has a functional group that easily charges positively, and the method of charging the electrode material is triboelectric charging with polytetrafluoroethylene, the electrode material is provided with a functional group that charges positively. As a result, the charge amount increases and the coating efficiency can be improved.
The functional group that is easily charged positively is not particularly limited, but is preferably an amino group or an amide group.
As a method of introducing the functional group into the electrode material, a method of introducing the functional group into the binder; a method of introducing the functional group into the charge control agent; to other electrode materials other than the binder and the charge control agent The method of introduce | transducing the said functional group is mentioned. Among them, the method of introducing the functional group into the binder and the method of introducing the functional group into the charge control agent are preferable in that the effect of improving the charge amount is great.

<Charge amount>
The amount of charge when the electrode material is triboelectrically charged can be measured as the average amount of charge of the electrode material by measuring the amount of current that the oppositely charged material flows to the ground when the electrode material is charged. The average charge amount of the electrode material is usually 0.5 μC / g or more, preferably 0.5 to 20.0 μC / g, more preferably 10.0 to 15.0 μC / g. When the average charge amount is within this range, the electrode material can be more efficiently applied on the current collector. As described above, the amount of charge can be adjusted by changing the amount and type of the conductive additive and binder.

<Grounding>
In the present invention, the current collector is preferably grounded. The ground resistance of the current collector is usually 1 MΩ or less, preferably 100Ω or less. When the ground resistance is in this range, effective induction charging is induced in the current collector when the frictionally charged electrode material approaches the vicinity of the current collector, so that a uniform electrode can be formed.

<Formation of electrode layer>
(Electrode material supply method)
In the present invention, the frictionally charged electrode material is supplied onto at least one surface of the current collector. There is no particular limitation on the method of supplying the frictionally charged electrode material onto the current collector. For example, a charged electrode material may be sprayed and supplied onto a grounded current collector as in electrostatic powder coating, or on a current collector installed as in electrostatic screen printing. The frictionally charged electrode material may be transferred.

  Then, the current collector and the electrode material supplied on the one surface by the supply method are pressurized with a pair of rolls to form an electrode layer on the current collector. In this step, the electrode material heated as necessary may be formed into a sheet-like electrode layer with a pair of rolls. The temperature of the electrode material supplied is preferably 40 to 160 ° C, more preferably 70 to 140 ° C. When an electrode material in this temperature range is used, there is no slip of the electrode material on the surface of the press roll, and the electrode material is continuously and uniformly supplied to the press roll. An electrode sheet for an electrochemical element with small variations can be obtained.

  In the present invention, the molding temperature is preferably 0 to 200 ° C., preferably higher than the melting point or glass transition temperature of the binder, and more preferably 20 ° C. or higher than the melting point or glass transition temperature of the binder. preferable. In the case of using a press roll, the forming speed is usually 10 m / min or more, preferably 20 to 200 m / min, more preferably 30 to 80 m / min, in order to make the moldability higher and make the film formation easier. . The press linear pressure between the press rolls is not particularly defined, but is preferably 0.2 to 30 kN / cm, more preferably 0.5 to 10 kN / cm in that the electrode strength of the obtained electrode can be increased. 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 the electrode material is supplied to at least one of the rolls, so that the electrode material is placed in the gap between the current collector and the rolls. The electrode layer can be formed by being supplied and pressurized. In the case of disposing substantially vertically, the current collector is conveyed in the horizontal direction, an electrode material is supplied onto the current collector, and a layer of electrode material 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 the thickness variation of the molded body, 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 roll press step, two cylindrical rolls are arranged vertically in a balanced manner at a narrow interval, each is rotated in the opposite direction, and the electrodes are sandwiched and pressed between them. The temperature of the roll may be adjusted by heating or cooling.

(Electrochemical element)
The electrochemical device of the present invention includes an electrode for an electrochemical device obtained by the production method of the present invention. Examples of the electrochemical element include a lithium ion secondary battery, an electric double layer capacitor, and a hybrid capacitor. An electric double layer capacitor is preferable. Hereinafter, the case where the electrode for an electrochemical element obtained by the production method of the present invention is used for an electrode for an electric double layer capacitor will be described.

  An electric double layer capacitor is comprised with an electrode, a separator, and electrolyte solution, and uses the electrode for electrochemical elements obtained with the manufacturing method of this invention as said electrode.

  The separator is not particularly limited as long as it can insulate between the electrodes and allow a cation and an anion 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. The separator is disposed between the electrodes so that the pair of electrode layers face each other, and an element is obtained. Although the thickness of a separator is suitably selected according to a use purpose, it is 1-100 micrometers normally, Preferably it is 10-80 micrometers, More preferably, it is 20-60 micrometers.

The electrolytic solution is usually composed of an electrolyte and a solvent. The electrolyte may be cationic or anionic. As the cationic electrolyte, (1) imidazolium, (2) quaternary ammonium, (3) quaternary phosphonium, (4) lithium and the like as shown below can be used.
(1) Imidazolium 1,3-Dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1,3-diethylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4-tetra Methylimidazolium, 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, diethyl Tetraalkylammonium such as dimethylammonium, triethylmethylammonium, tetraethylammonium, trimethylpropylammonium, etc. (3) Quaternary phosphonium Tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, methyltriethylphosphonium, methyltributylphosphonium, dimethyldiethylphosphonium, etc. 4) Lithium

In addition, examples of the anionic electrolyte include PF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , N (RfSO ₃ ) ²⁻ , C (RfSO ₃ ) ³⁻ , RfSO ₃ ⁻ (Rf is 1 carbon number, respectively). ˜12 fluoroalkyl groups), F ⁻ , ClO ₄ ⁻ , AlCl ₄ ⁻ , AlF ₄ ^{− and the} like. 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 can be used alone or as a mixed solvent of two or more. Of these, carbonates are preferable.

  The electrochemical element of the present invention is obtained by impregnating the above element with an electrolytic solution. Specifically, the capacitor element can be manufactured by winding, stacking, or folding into 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.

  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.

<Example 1>
100 parts of a high-purity activated carbon powder “Kuraray Coal YP-17D” (manufactured by Kuraray Chemical Co., Ltd.) having a specific surface area of 1,800 m ² / g and a volume average particle diameter of 5 μm as an electrode active material, and a volume average particle diameter of 0. 40% aqueous dispersion of 31 μm acrylate polymer (copolymer obtained by emulsion polymerization of n-butyl acrylate 40% by weight, ethyl methacrylate 40% by weight, n-butyl methacrylate 17% by weight, methacrylic acid 3% by weight) 5 parts by weight corresponding to the solid content, 5 parts of acetylene black (Denka black powder; manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 0.7 μm as a conductive assistant, and ammonium salt of “carboxymethyl cellulose” DN-800H as a dispersant ”(Manufactured by Daicel Chemical Industries, Ltd.) was added 1.4 parts in terms of solids and 348.7 parts ion-exchanged water. Mixer "solid concentration was 撹拝 mixed with (Primix Corp.) to obtain a 20% slurry. The pH of the slurry was 7.6 at 23 ° C. This slurry was adjusted to pH 8.5 with 25% aqueous ammonia, and using a spray dryer (OC-16; manufactured by Okawara Chemical Co., Ltd.), a rotating disk type atomizer (diameter 65 mm) with a rotation speed of 25,000 rpm and hot air Spray drying granulation was performed under the conditions of a temperature of 150 ° C. and a particle recovery outlet temperature of 90 ° C. to obtain composite particles of an electrode material. The composite particles had a weight average particle diameter of 54 μm.

  100 parts of carbon black having a volume average particle diameter of 0.7 μm and 4.0 parts of a carboxymethylcellulose 4.0% aqueous solution (DN-10L; manufactured by Daicel Chemical Industries) as a dispersant are equivalent to 4 parts in solid content and several parts as a binder. A conductive adhesive layer is formed by mixing a 40% aqueous dispersion of an acrylate polymer having an average particle size of 0.25 μm with a solid content equivalent of 8 parts and ion exchange water to a total solid content concentration of 30%. A slurry composition was prepared.

  The slurry composition for forming a conductive adhesive was applied to a current collector made of an aluminum foil having a thickness of 30 μm, and dried at 120 ° C. for 10 minutes to form a conductive adhesive layer having a thickness of 4 μm. Thereafter, the current collector on which the conductive adhesive layer was formed was grounded and installed horizontally. The grounding resistance was 10Ω.

Next, charging and supply of the composite particles were carried out using a friction charging electrostatic powder coating machine MTR-100VTmini manufactured by Asahi Sunac Corporation and a friction charging electrostatic powder manual gun T-2m type L7 manufactured by Asahi Sunac Corporation (inner sleeve and The outer sleeve was made of polytetrafluoroethylene. Specifically, the composite particles were put into a hopper of the powder coating machine, the rotation speed of a screw feeder for quantitative supply was adjusted, and the composite particles were supplied at 90 g / min. In addition, the carrier air pressure from the powder manual gun was set to 0.4 MPa, and composite particles were supplied to the current collector from above. The composite particles were charged by frictional charging generated when passing through the gap between the inner sleeve and outer sleeve of the powder manual gun. The current value at this time was 1.5 μA (C / second). The average charge amount of the charged composite particles was 1.0 μC / g. The coating efficiency on the current collector was calculated from the weight of the supplied electrode material and the weight of the electrode material in which the electrode material layer was formed on the current collector according to the following formula, and found to be 43%.
Coating efficiency (%) = weight of electrode material deposited on current collector / weight of supplied electrode material

When the appearance of the obtained electrode material layer was observed, it was confirmed that the electrode material was uniformly formed on the current collector. The current collector on which this electrode material layer is formed is supplied to a roll (roll temperature 120 ° C., press linear pressure 4 kN / cm) of a roll press machine (pressed rough surface heat roll, manufactured by Hirano Giken Kogyo Co., Ltd.). A thickened electrode layer was formed by pressure forming to produce an electrode for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ .

<Example 2>
In Example 1, an acrylate polymer (40% by weight of n-butyl acrylate, 40% by weight of ethyl methacrylate, 17% by weight of diethylaminomethyl methacrylate, and 3% by weight of methacrylic acid was emulsion-polymerized as a binder constituting the electrode layer. The electrode for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ is obtained in the same manner as in Example 1 except that a 40% aqueous dispersion of the above-mentioned copolymer is used. Manufactured. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 7.5 μA (average charge amount 5.0 μC / g), and the coating efficiency was 60%.

<Example 3>
In Example 1, an acrylate polymer (35% by weight of n-butyl acrylate, 35% by weight of ethyl methacrylate, 27% by weight of diethylaminomethyl methacrylate, and 3% by weight of methacrylic acid was emulsion-polymerized as a binder constituting the electrode layer. The electrode for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ is obtained in the same manner as in Example 1 except that a 40% aqueous dispersion of the above-mentioned copolymer is used. Manufactured. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 19.5 μA (average charge amount 13.0 μC / g), and the coating efficiency was 70%.

<Example 4>
100 parts of the composite particles obtained in Example 1 and 0.05 part of a charge control agent (manufactured by Soken Chemical Co., Ltd., “MP-5500”, styrene-methacrylic acid copolymer, average particle diameter 400 nm) are mixed with a Henschel mixer. (Mitsui Miike Co., Ltd.) was mixed for 10 minutes to obtain particles (externally added particles 1) in which the charge control agent was adhered to the composite particles.
In Example 1, the electrode layer thickness was 60 μm and the electrode layer density was 0.58 g / cm as in Example 1, except that the external additive particle 1 was used instead of the composite particles as the electrode material. ³ electric double layer capacitor electrodes were manufactured. There was no problem in the appearance of the electrode material layer, the current value when supplying the electrode material was 9.0 μA (average charge amount 6.0 μC / g), and the coating efficiency was 52%.

<Example 5>
In Example 4, except that the amount of the charge control agent was changed to 0.5 part, particles (externally added particles 2) in which the charge control agent was adhered to the composite particles were obtained in the same manner as in Example 4.
In Example 1, the electrode layer thickness was 60 μm and the electrode layer density was 0.58 g / cm, as in Example 1, except that the external additive particles 2 were used instead of composite particles as the electrode material. ³ electric double layer capacitor electrodes were manufactured. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 18.75 μA (average charge amount 12.5 μC / g), and the coating efficiency was 65%.

<Example 6>
In Example 4, particles (externally added particles 3) in which the charge control agent was adhered to the composite particles were obtained in the same manner as in Example 4 except that the amount of the charge control agent was 2.0 parts.
In Example 1, the electrode layer thickness was 60 μm and the electrode layer density was 0.58 g / cm, as in Example 1, except that the external additive particles 3 were used instead of composite particles as the electrode material. the ^third electrode for an electric double layer capacitor was produced. There was no problem in the appearance of the electrode material layer, the current value when supplying the electrode material was 22.5 μA (average charge amount 15.0 μC / g), and the coating efficiency was 80%.

<Example 7>
In Example 1, for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ , except that no adhesive layer was formed on the current collector. An electrode was manufactured. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 0.9 μA (average charge amount 0.6 μC / g), and the coating efficiency was 43%.

<Comparative Example 1>
In Example 1, the charging and supply of the electrode material was performed except that the corona charging electrostatic powder coating machine XR4-100ST manufactured by Asahi Sunac Corporation and the corona charging electrostatic powder hand gun X-3m + manufactured by Asahi Sunac Corporation were used. Produced an electrode for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ^{3 in} the same manner as in Example 1. A reverse ionization phenomenon occurred during the supply of the electrode material, and the appearance of the electrode material layer was impaired. The current value when the electrode material was supplied was 3.0 μA (average charge amount 2.0 μC / g), and the coating efficiency was 65%.

<Comparative example 2>
In Example 1, except that the PTFE inner sleeve and outer sleeve of the triboelectric electrostatic powder coating gun T-2m type L7 were replaced with stainless steel of the same shape. An electrode for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ was produced. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 0.0 μA (average charge amount 0.0 μC / g), and the coating efficiency was 8%.

The electrodes obtained in the above Examples and Comparative Examples were impregnated with an electrolytic solution (1.0 mol / L of a propylene carbonate solution of tetraethylammonium tetrafluoroborate) at room temperature for 1 hour, and then the two electrodes passed through a cellulose separator. The coin cell-shaped electric double layer capacitor was manufactured by placing each electrode layer so as to face each other and arranging the electrodes so as not to be in electrical contact. And the internal resistance of the produced electric double layer capacitor was measured.
The internal resistance was measured by performing the charge / discharge operation after allowing the produced coin cell to stand for 24 hours. Charging was performed at a constant current of 10 mA, and the internal resistance was calculated from the voltage drop after 0.1 seconds of discharge and the constant current value. The internal resistance value is shown in Table 1 as a relative value when the internal resistance value of Comparative Example 1 is 100%. The smaller the internal resistance value, the better.

  From the results in Table 1, the following can be understood. In Comparative Example 1, the electrode material is charged by corona discharge, and is charged by a method different from the method of the present invention in which the electrode material is charged by frictional charging. Therefore, although the coating efficiency is good, the thickness of the electrode is not uniform and the internal resistance is inferior. In Comparative Example 2, stainless steel having no fluorine-containing group is used for the inner sleeve and the outer sleeve, so that the electrode material adheres to the inner sleeve and the outer sleeve, and frictional charging does not occur. The body supply is not stable, the electrode thickness is not uniform, and the internal resistance is inferior.

  The method for producing an electrode for an electrochemical device according to the present invention is excellent in internal resistance and has a high coating efficiency of an electrode material. Can be suitably used.

  While the present invention has been described in connection with the most practical and preferred embodiments at the present time, the invention is not limited to the embodiments disclosed herein. The method of manufacturing an electrode for an electrochemical device with such a change is also within the technical scope of the present invention without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. It must be understood as included.

Claims (9)

A method for producing an electrode for an electrochemical element, wherein an electrode layer is formed by supplying an electrode material charged by frictional charging onto at least one surface of a current collector. The method for producing an electrode for an electrochemical element according to claim 1, wherein the frictional charging is charging by friction between the electrode material and a substance having a fluorine-containing group. The method for producing an electrode for an electrochemical element according to claim 1 or 2, wherein the substance having a fluorine-containing group is a fluorocarbon. The method for producing an electrode for an electrochemical element according to claim 1, wherein the electrode material is composite particles containing an electrode active material. The method for producing an electrode for an electrochemical element according to any one of claims 1 to 4, wherein the electrode material further contains a charge control agent. The method for producing an electrode for an electrochemical element according to any one of claims 1 to 5, wherein the electrode material includes a functional group that is easily positively charged. The method for producing an electrode for an electrochemical element according to claim 1, wherein the current collector has an adhesive layer on at least one surface. An electrochemical element provided with the electrode for electrochemical elements obtained by the manufacturing method in any one of Claims 1-7. The electrochemical device according to claim 8, wherein the electrochemical device is an electric double layer capacitor.