Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/20—Conductive material dispersed in non-conductive organic material
  • H01B1/24—Conductive material dispersed in non-conductive organic material the conductive material comprising carbon-silicon compounds, carbon or silicon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/22—Electrodes
  • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
  • H01G11/28—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials

Definitions

• the present invention relates to a composition for forming a conductive binding layer for an electricity storage device.
• lithium ion secondary batteries are the electricity storage devices that are currently being most actively developed because they have high energy density, high voltage, and have no memory effect during charging and discharging.
• Electric double layer capacitors and lithium ion capacitors which enable high-speed charging and discharging due to their high input/output characteristics and have a wide operating temperature range, are also attracting attention.
• the development of electric vehicles has been actively promoted, and the power storage devices used as their power sources are now required to have even higher performance.
• lithium ion secondary batteries, electric double layer capacitors, and lithium ion capacitors house a positive electrode and a negative electrode that can absorb and release lithium, and a separator interposed between them in a container, and an electrolyte (lithium) inside the container.
• an electrolyte lithium
• an ionic polymer secondary battery it has a structure filled with a gel-like or all-solid electrolyte instead of a liquid electrolyte.
• the positive and negative electrodes are generally made by coating a composition containing an active material that can absorb and release lithium, a conductive material mainly made of carbon material, and a polymer binder on a current collector such as copper foil or aluminum foil. It is manufactured by This binder is used to bond active materials and conductive materials, as well as these and metal foils, and is made of fluororesins soluble in N-methylpyrrolidone (NMP) such as polyvinylidene fluoride (PVdF), and styrene-butadiene.
• NMP N-methylpyrrolidone
• PVdF polyvinylidene fluoride
• Aqueous dispersions of rubber (SBR), carboxymethyl cellulose (CMC), and the like are commercially available.
• the adhesion of the above-mentioned binder to the current collector is not sufficient, and some of the active material and conductive material may peel off or fall off from the current collector during manufacturing processes such as cutting and winding the electrode. , causing micro short circuits and variations in battery capacity.
• the contact resistance between the electrode mixture and the current collector increases due to volume changes in the electrode mixture due to swelling of the binder by the electrolyte and volume changes due to lithium absorption and release from the active material.
• problems in terms of safety, as well as problems such as deterioration of battery capacity due to increase in the number of active materials or part of the active material or conductive material peeling off or falling off from the current collector.
• Patent Document 1 discloses a technique in which a conductive layer containing carbon as a conductive filler is disposed as an undercoat layer between a current collector and an electrode mixture layer.
• a composite current collector equipped with an undercoat layer it is possible to reduce the contact resistance between the current collector and the electrode composite layer, and also suppress capacity loss during high-speed discharge, which also prevents battery deterioration. It has been shown that it can be suppressed.
• Patent Document 4 and Patent Document 5 disclose an undercoat layer using carbon nanotubes (hereinafter also abbreviated as CNT) as a conductive filler.
• CNT carbon nanotubes
• the present invention has been made in view of the above circumstances, and can be suitably used for forming a conductive binding layer, particularly for reducing contact resistance between a current collector and an electrode composite layer in a power storage device.
• a conductive binder for power storage devices that can provide a conductive binder layer that can reduce the heat dissipation, improve the adhesion between the two, and maintain these properties even when exposed to high temperatures in an electrolytic solution.
• An object of the present invention is to provide a composition for forming a layer.
• carbon black has an average primary particle size and specific surface area within a specific range, and an olefin-unsaturated carboxylic acid (salt) copolymer.
• a composition containing copolymer particles and a water-containing solvent can reduce the contact resistance between the current collector and the electrode composite layer, improve the adhesion between the two, and can also be used at high temperatures.
• the present invention has been completed based on the discovery that it is possible to provide a conductive binding layer that does not lose these properties even when exposed to water.
• the present invention provides the following composition for forming a conductive binding layer for an electricity storage device.
• 1. Made from carbon black with an average primary particle diameter of 30 nm or less as measured by an electron microscope and a specific surface area of 100 to 1,000 m 2 /g as measured by a nitrogen adsorption method, and an olefin-unsaturated carboxylic acid (salt) copolymer.
• a composition for forming a conductive binding layer for an electricity storage device comprising copolymer particles consisting of the following: and a solvent containing water. 2.
• composition for forming a conductive bonding layer for a power storage device wherein the olefin-unsaturated carboxylic acid (salt) copolymer is an ethylene-(meth)acrylic acid (salt) copolymer.
• the composition for forming a conductive binding layer for a power storage device according to any one of 1 to 3 wherein the copolymer particles have an average particle diameter of 100 nm or less as measured by a call counter method.
• An electric double layer capacitor comprising 12 electric double layer capacitor electrodes.
• the composition for forming a conductive binding layer for an electricity storage device of the present invention is suitable as a composition for forming a conductive binding layer that joins a current collector and an electrode composite layer that constitute an electrode of an electricity storage device.
• a conductive bonding layer is formed on the current collector using the composition, it is possible to reduce the contact resistance between the current collector and the electrode composite layer, and it also has excellent high-temperature durability. properties can also be imparted, and the characteristics of the resulting electricity storage device can be improved.
• solid content means components other than the solvent that constitute the composition.
• Carbon black includes acetylene black, furnace black, channel black, thermal black, and Ketjen black, and the type of hardness may be hard carbon, soft carbon, or any other type.
• the average primary particle diameter of carbon black measured using an electron microscope improves the coating area during coating, improves the uniformity of the coating thickness on the coating surface, and reduces the interfacial resistance between the current collector and the electrode mixture layer.
• the thickness is 30 nm or less, preferably 25 nm or less, from the viewpoint of improving the adhesion between the two and improving the high-temperature durability of the electricity storage device. Further, the lower limit thereof is not particularly limited, but from the viewpoint of improving electronic conductivity, it is preferably 3 nm or more, more preferably 5 nm or more.
• the average primary particle diameter of the carbon black is a value obtained using a measurement method using an electron microscope according to ASTM D3849.
• the specific surface area of carbon black measured by the nitrogen adsorption method improves the coating area during coating, improves the uniformity of the coating film thickness, reduces the interfacial resistance between the current collector and the electrode mixture layer, From the viewpoint of improving the adhesion between the two and the high-temperature durability of the electricity storage device, it is 100 to 1,000 m 2 /g, preferably 100 to 300 m 2 /g.
• the above specific surface area is a value obtained using a nitrogen adsorption method according to JIS K6217-2.
• Examples of the carbon black include CB1, CB4 (Asahi Carbon Co., Ltd.), NH carbon type C, NH carbon type F (Nippon Chemi-Con Co., Ltd.), and Denka Black Li-435 (manufactured by Denka Co., Ltd.). .
• the content of the carbon black is preferably more than 30% by mass to 70% by mass, more preferably 50 to 70% by mass in the solid content.
• the above olefin usually has 2 or more carbon atoms, preferably 8 or less carbon atoms, particularly 6 or less carbon atoms, and specifically Examples include ethylene, propylene, butene, pentene, hexene, heptene, octene and the like, with ethylene being particularly preferred.
• Examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, fumaric acid, etc., with (meth)acrylic acid being particularly preferred.
• a part of the unsaturated carboxylic acid may be a salt.
• the salts of unsaturated carboxylic acids include those obtained by neutralizing the above-mentioned unsaturated carboxylic acids with metal ions such as sodium ions, potassium ions, lithium ions, and ammonium ions.
• Specific examples of unsaturated carboxylic acid salts include sodium salts, potassium salts, lithium salts, and ammonium salts of methacrylic acid, acrylic acid, and the like.
• copolymers include ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, propylene-methacrylic acid copolymer, partially neutralized sodium salt of ethylene-methacrylic acid copolymer, and ethylene-methacrylic acid copolymer.
• examples include partially neutralized lithium salts of methacrylic acid copolymers, partially neutralized ammonium salts of ethylene-methacrylic acid copolymers, partially neutralized sodium salts of ethylene-methacrylic acid copolymers, and partially neutralized sodium salts of ethylene-methacrylic acid copolymers.
• Partially neutralized lithium salts of polymers and partially neutralized ammonium salts of ethylene-methacrylic acid copolymers are preferred.
• the proportion of olefin in the above copolymer is preferably 60 to 95 mol% of the structural units derived from all monomers.
• the proportion of unsaturated carboxylic acid in the above copolymer is preferably 5 to 40 mol% of the structural units derived from all monomers.
• the proportion thereof is preferably 5 to 50 mol% of the structural units derived from the unsaturated carboxylic acid.
• the average particle diameter of the copolymer particles consisting of an olefin-unsaturated carboxylic acid (salt) copolymer improves the dispersibility in carbon black, increases the coating area during coating, and improves the uniformity of the film thickness on the coating surface.
• the thickness is preferably 1 ⁇ m or less, more preferably 200 nm or less, and even more Preferably it is less than 100 nm.
• the lower limit thereof is not particularly limited, but from the viewpoint of improving the uniformity of the film thickness on the coating film surface and improving the heat resistance of the coating film, the lower limit is preferably 1 nm or more, more preferably 10 nm or more.
• the primary particle diameter of the above-mentioned copolymer particles is a value measured by a coal counter method.
• the above copolymer particles can also be obtained as commercial products, and examples of such commercial products include Chemipearl S100 (manufactured by Mitsui Chemicals, Inc.), Zaixen A, Zaixen AC, Zaixen AC-HW-10, Examples include Zaixen L, Zaixen NC, Zaixen N (manufactured by Sumitomo Seika Co., Ltd.), Arrowbase SE-1200 (manufactured by Unitika Co., Ltd.), and the like.
• the content of the above-mentioned copolymer particles is determined based on the solid content of the remainder (solid content) other than the above-mentioned carbon black (if other conductive carbon materials described below are included, the total of the other conductive carbon materials and carbon black). (remaining part), and the solid content is preferably 30% by mass or more and less than 70% by mass, more preferably 30 to 50% by mass.
• the composition of the present invention contains other components described below (however, excluding other conductive carbon materials described below.Hereinafter, may be referred to as optional components), the above optional components are the solid components described above. (i.e., the remainder of the solids is comprised of the copolymer particles and optional ingredients). Moreover, the above-mentioned copolymer particles may be used alone or in combination of two or more types.
• the solvent used for preparing the composition of the present invention includes water, but may also include a hydrophilic solvent in addition to water.
• Hydrophilic solvents are organic solvents that mix arbitrarily with water, such as ethers such as tetrahydrofuran (THF); N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl Amides such as -2-pyrrolidone (NMP); Ketones such as acetone; Alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, t-butanol; ethylene glycol monoethyl ether, ethylene glycol Examples include organic solvents such as glycol ethers such as monobutyl ether and propylene glycol monomethyl ether; and glycols such as ethylene glycol and propylene glycol.
• alcohol is preferable in consideration of improving the dispersibility in carbon black, increasing the coating area during coating, and improving the uniformity of the coating thickness on the coating surface, and methanol, ethanol, 1-propanol and 2-propanol are more preferred.
• solvents may be used alone or in combination of two or more.
• the content should be 10% by mass or more in the solvent from the viewpoints of improving dispersibility in carbon black, increasing coating area during coating, and improving film thickness uniformity on the coating surface. is preferable, and 30% by mass or more is more preferable. Further, the upper limit thereof is not particularly limited, but is preferably 90% by mass or less in the solvent.
• composition of the present invention may contain conductive carbon materials other than the above-mentioned carbon black to the extent that the effects of the present invention are not impaired.
• the other conductive carbon materials mentioned above can be appropriately selected from known conductive carbon materials such as carbon whiskers, carbon nanotubes (CNTs), carbon fibers, natural graphite, and artificial graphite.
• CNTs are generally produced by an arc discharge method, a chemical vapor deposition method (CVD method), a laser ablation method, etc., but the CNTs used in the present invention may be obtained by any method.
• CNTs include single-layer CNTs (hereinafter also abbreviated as SWCNTs) in which one carbon film (graphene sheet) is wound into a cylindrical shape, and two-layer CNTs in which two graphene sheets are wound concentrically.
• SWCNTs single-layer CNTs
• DWCNTs single-layer CNTs
• MWCNTs multilayer CNTs
• catalyst metals such as nickel, iron, cobalt, and yttrium may remain, so purification may be required to remove these impurities.
• acid treatment with nitric acid, sulfuric acid, etc. and ultrasonic treatment are effective.
• acid treatment with nitric acid, sulfuric acid, or the like may destroy the ⁇ -conjugated system that constitutes CNTs and impair the original properties of CNTs, so it is desirable to purify them under appropriate conditions before use.
• Baytubes [Manufactured by Bayer Company: Product Name], GRAPHISTRENGTH [Manufactured by Arkema Company: Product Name], MWNT7 [Manufactured by Hodogaya Chemical Industry Co., Ltd.: Product Name], Hyperion CNT [Hyperion Catalysis Inter] Made by national : trade name], TC series [manufactured by Toda Kogyo Co., Ltd.: trade name], FloTube series [manufactured by Jiangsu Cnano Technology Co., Ltd.: trade name], and the like.
• the other conductive carbon materials mentioned above are included, their content is preferably 0 to 20% by mass, and 0 to 20% by mass based on the solid content, from the viewpoint of dispersion stability of the carbon material, internal resistance of the electricity storage device, and coating uniformity. 10% by mass is more preferred, and 0.01 to 10% by mass is more preferred. Further, at this time, the total amount of carbon black and other conductive carbon materials is preferably within a range of 70% by mass or less based on the solid content. Note that the other conductive carbon materials mentioned above may be used alone or in combination of two or more.
• the composition of the present invention may contain other dispersants in addition to the olefin-unsaturated carboxylic acid (salt) copolymer in order to improve the dispersibility of the carbon black and other conductive carbon materials. good.
• the dispersant can be appropriately selected from those conventionally used as dispersants for carbon black, etc., such as carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), acrylic resin emulsion, and water-soluble acrylic polymer.
• styrene emulsion silicone emulsion, acrylic silicone emulsion, fluororesin emulsion, EVA emulsion, vinyl acetate emulsion, vinyl chloride emulsion, urethane resin emulsion, triarylamine-based hyperbranched polymer described in International Publication No. 2014/042080, International Publication No.
• examples include polymers having an oxazoline group in the side chain described in International Publication No. 2015/029949, but in the present invention, dispersants containing polymers having an oxazoline group in the side chain described in International Publication No. 2015/029949, It is preferable to use a dispersant containing a triarylamine-based highly branched polymer described in No. 2014/042080.
• the polymer having an oxazoline group in the side chain (hereinafter referred to as oxazoline polymer) is obtained by radical polymerization of an oxazoline monomer having a polymerizable carbon-carbon double bond-containing group at the 2-position as shown in formula (1).
• oxazoline polymer A vinyl polymer having an oxazoline group in its side chain and having a repeating unit bonded to the polymer main chain or spacer group at the 2-position of the oxazoline ring is preferred.
• R 1 to R 4 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, and a group having 6 to 20 carbon atoms. Represents an aryl group or an aralkyl group having 7 to 20 carbon atoms.
• the polymerizable carbon-carbon double bond-containing group possessed by the oxazoline monomer is not particularly limited as long as it contains a polymerizable carbon-carbon double bond;
• a hydrocarbon group such as a vinyl group, an allyl group, an isopropenyl group, or an alkenyl group having 2 to 8 carbon atoms is preferable.
• the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
• the alkyl group having 1 to 5 carbon atoms may be linear, branched, or cyclic, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group. , tert-butyl group, n-pentyl group, cyclohexyl group and the like.
• Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, xylyl group, tolyl group, biphenyl group, and naphthyl group.
• Examples of the aralkyl group having 7 to 20 carbon atoms include benzyl group, phenylethyl group, and phenylcyclohexyl group.
• Examples of the oxazoline monomer having a polymerizable carbon-carbon double bond-containing group at the 2-position represented by formula (1) include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl -4-ethyl-2-oxazoline, 2-vinyl-4-propyl-2-oxazoline, 2-vinyl-4-butyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-vinyl-5 -Ethyl-2-oxazoline, 2-vinyl-5-propyl-2-oxazoline, 2-vinyl-5-butyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2 -Oxazoline, 2-isopropenyl-4-ethyl-2-oxazoline, 2-isopropenyl-4-propyl-2-oxazoline, 2-isopropenyl-4-but
• the oxazoline polymer is also water-soluble.
• a water-soluble oxazoline polymer may be a homopolymer of the oxazoline monomer represented by the above formula (1), but in order to further increase the solubility in water, it may be a homopolymer of the oxazoline monomer and the above oxazoline monomer having a hydrophilic functional group (meth). ) It is preferably obtained by radical polymerizing at least two types of monomers with an acrylic acid ester monomer.
• Examples of (meth)acrylic monomers having a hydrophilic functional group include (meth)acrylic acid, 2-hydroxyethyl acrylate, methoxypolyethylene glycol acrylate, monoester of acrylic acid and polyethylene glycol, and 2-amino acrylate.
• Ethyl and its salts 2-hydroxyethyl methacrylate, methoxypolyethylene glycol methacrylate, monoester of methacrylic acid and polyethylene glycol, 2-aminoethyl methacrylate and its salts, sodium (meth)acrylate, (meth)acrylic Ammonium acid, (meth)acrylonitrile, (meth)acrylamide, N-methylol (meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, sodium styrene sulfonate, etc., and these can be used alone. However, two or more types may be used in combination. Among these, methoxypolyethylene glycol (meth)acrylate and a monoester of (meth)acrylic acid and polyethylene glycol are preferred.
• monomers other than the above-mentioned oxazoline monomer and the (meth)acrylic monomer having a hydrophilic functional group can be used in combination within a range that does not adversely affect the carbon dispersion ability of the oxazoline polymer.
• Other monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, and perfluorinated (meth)acrylate.
• (meth)acrylic acid ester monomers such as ethyl and phenyl (meth)acrylate; olefin monomers such as ethylene, propylene, butene, and pentene; haloolefin monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; styrene, ⁇ - Styrenic monomers such as methylstyrene; carboxylic acid vinyl ester monomers such as vinyl acetate and vinyl propionate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether.
• the above may be used in combination.
• the content of the oxazoline monomer is preferably 10% by mass or more, and more preferably 20% by mass or more, from the viewpoint of further increasing the carbon dispersion ability of the obtained oxazoline polymer. Preferably, 30% by mass or more is even more preferable. Note that the upper limit of the content of oxazoline monomer in the monomer component is 100% by mass, and in this case, a homopolymer of oxazoline monomer is obtained.
• the content of the (meth)acrylic monomer having a hydrophilic functional group in the monomer component is preferably 10% by mass or more, more preferably 20% by mass or more. , 30% by mass or more is even more preferable.
• the content of other monomers in the monomer component is within a range that does not affect the carbon dispersion ability of the obtained oxazoline polymer, and it cannot be determined unconditionally because it varies depending on the type. It may be set appropriately within a range of preferably 5 to 95% by mass, more preferably 10 to 90% by mass.
• the average molecular weight of the oxazoline polymer is not particularly limited, but the weight average molecular weight is preferably 1,000 to 2,000,000, more preferably 2,000 to 1,000,000. Note that the weight average molecular weight is a polystyrene equivalent value determined by gel permeation chromatography.
• the oxazoline polymer that can be used in the present invention can be synthesized by conventionally known radical polymerization of the above monomers, but it can also be obtained as a commercially available product.
• Such commercial products include, for example, Epocross WS-300 (manufactured by Nippon Shokubai Co., Ltd., solid content concentration 10% by mass, aqueous solution), Epocross WS-700 (manufactured by Nippon Shokubai Co., Ltd., solid content concentration 25% by mass).
• Epocross WS-500 manufactured by Nippon Shokubai Co., Ltd., solid content concentration 39% by mass, water/1-methoxy-2-propanol solution
• Poly (2-ethyl-2-oxazoline) Aldrich
• Poly (2-ethyl-2-oxazoline) Alfa Aesar
• Poly(2-ethyl-2-oxazoline) VWR International, LLC
• it when it is commercially available as a solution, it may be used as it is or after being replaced with the desired solvent.
• the oxazoline polymer causes a crosslinking reaction with the copolymer particles, so it also functions as a crosslinking agent, which will be described later.
• the above-mentioned dispersant when the above-mentioned dispersant is included, its content is preferably 0.001 to 1,000 parts by mass, more preferably 0.001 to 100 parts by mass, based on 100 parts by mass of the copolymer particles. Even more preferably, it is 0.001 to 50 parts by mass.
• composition of the present invention may contain a crosslinking agent that causes a crosslinking reaction with the above-mentioned copolymer particles and a dispersant used as necessary, or a crosslinking agent that self-crosslinks, within a range that does not impair the effects of the present invention. You can stay there.
• crosslinking agents are preferably dissolved in the solvent used.
• crosslinking agents examples include melamine-based, substituted urea-based, and polymer-based crosslinking agents, and these crosslinking agents can be used alone or in combination of two or more.
• the crosslinking agent has at least two crosslinking substituents, such as CYMEL (registered trademark), methoxymethylated glycoluril, butoxymethylated glycoluril, methylolated glycoluril, methoxymethylated melamine, butoxymethyl.
• the oxazoline polymer also functions as a crosslinking agent, so it may be blended as a crosslinking agent in the present invention.
• crosslinking agent can cause a crosslinking reaction with the olefin-unsaturated carboxylic acid (salt) copolymer, but it is also possible to add another type of crosslinking agent that reacts with the crosslinking agent.
• Other types of crosslinking agents are particularly limited as long as they are compounds that have two or more functional groups that are reactive with oxazoline groups, such as carboxy groups, hydroxyl groups, thiol groups, amino groups, sulfinic acid groups, and epoxy groups. However, compounds having two or more carboxy groups are preferred.
• compounds having functional groups that cause a crosslinking reaction when heated during thin film formation or in the presence of an acid catalyst such as sodium salts, potassium salts, lithium salts, and ammonium salts of carboxylic acids, can also be crosslinked. It can be used as an agent.
• crosslinking agents include metal salts of synthetic polymers such as polyacrylic acid and its copolymers and natural polymers such as carboxymethylcellulose and alginic acid, which exhibit crosslinking reactivity with oxazoline groups in the presence of an acid catalyst;
• examples include ammonium salts of the synthetic polymers and natural polymers mentioned above that exhibit crosslinking reactivity when heated, but especially sodium polyacrylate and polyamide salts that exhibit crosslinking reactivity in the presence of an acid catalyst or under heating conditions.
• Preferred are lithium acrylate, ammonium polyacrylate, sodium carboxymethylcellulose, lithium carboxymethylcellulose, ammonium carboxymethylcellulose, and the like.
• Compounds that cause crosslinking reactions with such oxazoline groups can also be obtained as commercial products, such as sodium polyacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., polymerization degree 2). , 700 to 7,500), sodium carboxymethylcellulose (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), sodium alginate (manufactured by Kanto Chemical Co., Ltd., grade 1), Aron A-30 (ammonium polyacrylate, Toagosei Co., Ltd.) Co., Ltd., solid content concentration 32% by mass, aqueous solution), DN-800H (carboxymethylcellulose ammonium, manufactured by Daicel FineChem Co., Ltd.), ammonium alginate (manufactured by Kimica Co., Ltd.), and the like.
• sodium polyacrylate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., polymerization degree 2). , 700 to 7,500
• sodium carboxymethylcellulose manufactured by Fujifilm Wako
• Compounds that have crosslinkable functional groups that react with each other, such as isocyanate groups and aldehyde groups, in the same molecule, hydroxyl groups (dehydration condensation), mercapto groups (disulfide bonds), etc. that react with the same crosslinkable functional groups Examples include compounds having an ester group (Claisen condensation), a silanol group (dehydration condensation), a vinyl group, an acrylic group, and the like.
• examples include block copolymers of monomers having
• Such self-crosslinking crosslinking agents can also be obtained as commercial products, and examples of such commercial products include A-9300 (ethoxylated isocyanuric acid triacrylate, Shin Nakamura Chemical Co., Ltd.) for polyfunctional acrylates. Co., Ltd.), A-GLY-9E (Ethoxylated glycerine triacrylate (EO9mol), Shin Nakamura Chemical Co., Ltd.), A-TMMT (pentaerythritol tetraacrylate, Shin Nakamura Chemical Co., Ltd.), tetraalkoxysilane
• tetramethoxysilane manufactured by Tokyo Chemical Industry Co., Ltd.
• tetraethoxysilane manufactured by Toyoko Chemical Co., Ltd.
• polymers having blocked isocyanate groups include Elastron series E-37, H-3, H38, BAP, Examples include NEW BAP-15, C-52, F-29, W-11P, MF
• crosslinking agent When a crosslinking agent is included, its content varies depending on the solvent used, the base material used, the required viscosity, the required film shape, etc., but it is preferably 0 parts per 100 parts by mass of the copolymer particles. The amount is .001 to 1,000 parts by weight, more preferably 0.001 to 100 parts by weight, even more preferably 0.001 to 50 parts by weight.
• crosslinking agents may cause a crosslinking reaction by self-condensation, but they also cause a crosslinking reaction with the dispersant, and if there are crosslinking substituents in the dispersant, the crosslinking reaction will be caused by those crosslinking substituents. is promoted.
• a polymer serving as a matrix may be added to the composition of the present invention.
• matrix polymers include polyvinylidene fluoride (PVdF), polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer [P(VDF-HFP)], and fluoride.
• Fluorine resins such as vinylidene chloride-trifluoroethylene chloride copolymer [P(VDF-CTFE)]; polyvinylpyrrolidone, ethylene-propylene-diene terpolymer, PE (polyethylene), PP (polypropylene), EVA Polyolefin resins such as (ethylene-vinyl acetate copolymer), EEA (ethylene-ethyl acrylate copolymer); PS (polystyrene), HIPS (high-impact polystyrene), AS (acrylonitrile-styrene copolymer), ABS (acrylonitrile-butadiene-styrene copolymer), MS (methyl methacrylate-styrene copolymer), polystyrene resins such as styrene-butadiene rubber; polycarbonate resin; vinyl chloride resin; polyamide resin; polyimide resin; sodium polyacrylate , (meth)acrylic resin
• water-soluble matrix polymers such as sodium polyacrylate, sodium carboxymethylcellulose, and water-soluble Among them, sodium polyacrylate, sodium carboxymethylcellulose and the like are particularly preferred.
• Matrix polymers can also be obtained as commercial products, such as sodium polyacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., polymerization degree 2,700 to 7,500), carboxylic Sodium methylcellulose (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), sodium alginate (manufactured by Kanto Chemical Co., Ltd., grade 1), Metrose SH series (hydroxypropyl methylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd.), Metrose SE series (manufactured by Shin-Etsu Chemical Co., Ltd.) Hydroxyethyl methyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd.), JC-25 (completely saponified polyvinyl alcohol, manufactured by Japan Vinyl Acetate Poval Co., Ltd.), JM-17 (intermediately saponified polyvinyl alcohol, manufactured by Japan Vinyl Acetate Poval Co., Ltd.) (manufactured by Poval Co.,
• its content is not particularly limited, but is preferably 0.001 to 1,000 parts by mass, more preferably 0.001 parts by mass, based on 100 parts by mass of copolymer particles. ⁇ 900 parts by mass.
• the method for preparing the composition of the present invention is not particularly limited, but carbon black, copolymer particles, solvent, and other components used as necessary are mixed in any order to prepare a dispersion. Just prepare it. Further, from the viewpoint of highly dispersing carbon black and obtaining a uniform dispersion, it is preferable to perform a dispersion treatment on the mixture. Examples of dispersion processing include mechanical processing, such as wet processing using a ball mill, bead mill, jet mill, etc., and ultrasonic processing using a bath-type or probe-type sonicator, but in particular, wet processing using a jet mill. or ultrasonic treatment are suitable.
• the time for the dispersion treatment is arbitrary, but is preferably about 1 minute to 10 hours, more preferably about 5 minutes to 5 hours. At this time, stirring treatment, cooling treatment, heating treatment, etc. may be performed as necessary.
• the solid content concentration of the composition is not particularly limited, but considering the formation of a conductive binding layer (undercoat layer) with a desired basis weight and film thickness, the solid content concentration of the composition is 20% by mass. It is preferably at most 15% by mass, more preferably at most 10% by mass, even more preferably at most 8% by mass. Further, the lower limit is arbitrary, but from a practical standpoint, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more.
• An undercoat foil (composite current collector) can be produced by applying the composition described above to at least one surface of a current collector and drying it naturally or by heating to form an undercoat layer.
• the current collector those conventionally used as current collectors for electrodes for electricity storage devices can be used.
• copper, aluminum, titanium, stainless steel, nickel, gold, silver, alloys of these, carbon materials, metal oxides, conductive polymers, etc. can be used, but welding such as ultrasonic welding can be used.
• metal foil made of copper, aluminum, titanium, stainless steel, or an alloy thereof.
• the thickness of the current collector is not particularly limited, but in the present invention, it is preferably 1 to 100 ⁇ m.
• Examples of methods for applying the composition include spin coating, dip coating, flow coating, inkjet, casting, spray coating, bar coating, gravure coating, slit coating, roll coating, and flexographic printing.
• method transfer printing method, brush coating method, blade coating method, air knife coating method, die coating method, etc.; however, from the point of view of work efficiency, inkjet method, casting method, dip coating method, bar coating method, blade coating method, etc. , a roll coating method, a gravure coating method, a flexographic printing method, a spray coating method, and a die coating method are suitable.
• the temperature for heating and drying is also arbitrary, but it is preferably about 30 to 200°C, more preferably about 50 to 150°C.
• the thickness of the undercoat layer is preferably 50 nm or more, more preferably 100 nm or more, and even more preferably 500 nm or more, in consideration of internal resistance reduction of the resulting device, film thickness uniformity, and peeling resistance of the undercoat and electrode layer. Further, from the same point of view, the upper limit thereof is preferably 20 ⁇ m or less, more preferably 10 ⁇ m or less, and even more preferably 3 ⁇ m or less.
• the thickness of the undercoat layer can be determined, for example, by cutting a test piece of an appropriate size from the undercoat foil, exposing the cross section using a focused ion beam method, etc., and observing the cross section with a microscope such as a scanning electron microscope (SEM). It can be determined from the exposed portion of the undercoat layer. For an undercoat layer formed on metal foil with a thickness of 1 ⁇ m or more, it may be calculated by directly measuring using a micrometer or the like and subtracting the thickness of the metal foil.
• the basis weight of the undercoat layer per surface of the current collector is not particularly limited as long as it satisfies the above film thickness, but is preferably 20 g/m 2 or less, more preferably 10 g/m 2 or less, and 3 g/m 2 or less. 2 or less is even more preferable.
• the basis weight of the undercoat layer per surface of the current collector is preferably 50 mg/m 2 or more, more preferably 100 mg/m 2 or more. m 2 or more, more preferably 300 mg/m 2 or more, still more preferably 500 mg/m 2 or more.
• the basis weight of the undercoat layer is the ratio of the mass (mg) of the undercoat layer to the area (m 2 ) of the undercoat layer, and when the undercoat layer is formed in a pattern, the area is This is the area of only the coat layer and does not include the area of the current collector exposed between the patterned undercoat layers.
• the mass of the undercoat layer can be determined by, for example, cutting out a test piece of an appropriate size from the undercoat foil, measuring its mass W0, then peeling the undercoat layer from the undercoat foil, and then peeling off the undercoat layer. Measure the mass W1 of the current collector and calculate from the difference (W0-W1), or measure the mass W2 of the current collector in advance and then measure the mass W3 of the undercoat foil on which the undercoat layer is formed. , can be calculated from the difference (W3-W2). Examples of the method for peeling off the undercoat layer include a method of immersing the undercoat layer in a solvent that dissolves or swells the undercoat layer, and wiping off the undercoat layer with a cloth or the like.
• the basis weight and film thickness can be adjusted using known methods. For example, when forming an undercoat layer by coating, the solid content concentration of the coating solution (composition for forming an undercoat layer) for forming the undercoat layer, the number of coatings, the coating solution input port of the coating machine, etc. It can be adjusted by changing the clearance etc. If you want to increase the basis weight or film thickness, increase the solid content concentration, increase the number of applications, or increase the clearance. If you want to reduce the basis weight or film thickness, lower the solid content concentration, reduce the number of applications, or reduce the clearance.
• the electrode for a power storage device of the present invention can be produced by forming an electrode mixture layer on the undercoat layer.
• power storage devices in the present invention include various energy storage devices such as electric double layer capacitors (EDLC), lithium secondary batteries, lithium ion secondary batteries, proton polymer batteries, nickel-metal hydride batteries, aluminum solid capacitors, electrolytic capacitors, and lead-acid batteries.
• EDLC electric double layer capacitors
• lithium secondary batteries lithium ion secondary batteries
• proton polymer batteries nickel-metal hydride batteries
• aluminum solid capacitors aluminum solid capacitors
• electrolytic capacitors electrolytic capacitors
• lead-acid batteries examples include storage devices, and the undercoat foil of the present invention can be particularly suitably used for electric double layer capacitors, lithium ion capacitors, and lithium ion secondary batteries.
• the electrode mixture layer can be formed by applying an electrode slurry prepared by combining an active material, a binder polymer, and an optional solvent onto the undercoat layer, and drying it naturally or by heating.
• the active material various active materials conventionally used in electrodes for electricity storage devices can be used.
• chalcogen compounds capable of adsorbing and desorbing lithium ions, chalcogen compounds containing lithium ions, polyanionic compounds, elemental sulfur, and compounds thereof can be used as positive electrode active materials. can.
• Examples of chalcogen compounds capable of adsorbing and desorbing lithium ions include FeS 2 , TiS 2 , MoS 2 , V 2 O 6 , V 6 O 13 , MnO 2 and the like.
• Examples of lithium ion-containing chalcogen compounds include LiCoO 2 , LiMnO 2 , LiMn 2 O 4 , LiMo 2 O 4 , LiV 3 O 8 , LiNiO 2 , Li x Ni y M 1-y O 2 (where M is Represents at least one metal element selected from Co, Mn, Ti, Cr, V, Al, Sn, Pb, and Zn, 0.05 ⁇ x ⁇ 1.10, 0.5 ⁇ y ⁇ 1.0 ) etc.
• Examples of the polyanionic compound include LiFePO 4 and the like.
• Examples of the sulfur compound include Li 2 S and rubeanic acid.
• the negative electrode active material constituting the negative electrode at least one element, oxide, sulfide, or nitride selected from alkali metals, alkali alloys, and elements of groups 4 to 15 of the periodic table that occlude and release lithium ions is used.
• a carbon material that can reversibly absorb and release lithium ions can be used.
• Examples of the alkali metal include Li, Na, and K, and examples of the alkali metal alloy include Li-Al, Li-Mg, Li-Al-Ni, Na-Hg, and Na-Zn.
• Examples of the simple substance of at least one element selected from the elements of groups 4 to 15 of the periodic table that absorb and release lithium ions include silicon, tin, aluminum, zinc, arsenic, and the like.
• oxides include silicon monoxide (SiO), silicon dioxide (SiO 2 ), tin silicon oxide (SnSiO 3 ), lithium bismuth oxide (Li 3 BiO 4 ), lithium zinc oxide (Li 2 ZnO 2 ), and lithium.
• Examples include titanium oxide (Li 4 Ti 5 O 12 ) and titanium oxide.
• examples of the sulfide include lithium iron sulfide (Li x FeS 2 (0 ⁇ x ⁇ 3)), lithium copper sulfide (Li x CuS (0 ⁇ x ⁇ 3)), and the like.
• Examples of carbon materials capable of reversibly occluding and releasing lithium ions include graphite, carbon black, coke, glassy carbon, carbon fibers, carbon nanotubes, and sintered bodies thereof.
• a carbonaceous material can be used as the active material.
• the carbonaceous material include activated carbon with a high specific surface area, such as activated carbon obtained by carbonizing a synthetic resin such as a phenol resin or a natural product such as a coconut shell, followed by activation treatment.
• the composition for forming a conductive binding layer for an electricity storage device of the present invention can be suitably used in an electrode of an electric double layer capacitor, and particularly when activated carbon is used as the active material, higher effects are expected.
• the binder polymer can be appropriately selected from known materials, such as polyvinylidene fluoride (PVdF), polyvinylpyrrolidone, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and vinylidene fluoride.
• PVdF polyvinylidene fluoride
• polyvinylpyrrolidone polyvinylpyrrolidone
• polytetrafluoroethylene polytetrafluoroethylene-hexafluoropropylene copolymer
• vinylidene fluoride vinylidene fluoride
• Hexafluoropropylene copolymer [P(VDF-HFP)], vinylidene fluoride-trifluoroethylene chloride copolymer [P(VDF-CTFE)], polyvinyl alcohol, polyimide, ethylene-propylene-diene ternary copolymer Examples include rubber, styrene-butadiene rubber (SBR), carboxymethylcellulose (CMC), polyacrylic acid (PAA), polyaniline, polyimide, and polyamide.
• the content of the binder polymer is preferably 0.1 to 40 parts by weight, particularly 1 to 30 parts by weight, based on 100 parts by weight of the active material.
• the solvent examples include the solvents exemplified as solvents for the composition, and may be appropriately selected from among them depending on the type of binder.
• a water-insoluble binder such as PVdF
• NMP is preferable.
• water-soluble binders such as SBR-CMC and PAA
• water is suitable.
• the electrode slurry may contain a conductive material.
• the conductive material include carbon black, Ketjenblack, acetylene black, carbon whiskers, carbon fibers, natural graphite, artificial graphite, titanium oxide, ruthenium oxide, aluminum, and nickel.
• Examples of the method for applying the electrode slurry include the same method as the method for applying the composition described above.
• the temperature for heating and drying is also arbitrary, but is preferably about 50 to 400°C, more preferably about 50 to 150°C. At this time, heating and drying may be performed under reduced pressure or vacuum.
• the electrode may be pressed if necessary.
• the press pressure is preferably 30 kN/cm or less.
• the pressing method any commonly employed method can be used, but a mold pressing method or a roll pressing method is particularly preferred.
• the press pressure is not particularly limited, but is preferably 10 kN/cm or less, more preferably 5 kN/cm or less.
• the electricity storage device includes the above-mentioned electrode for an electricity storage device, and more specifically, includes at least a pair of positive and negative electrodes, a separator interposed between these electrodes, and an electrolyte. At least one of the positive and negative electrodes is constituted by the above-mentioned electrode for an electricity storage device.
• this electricity storage device is characterized by using the above-mentioned electrode for electricity storage devices as an electrode, other device constituent members such as a separator and an electrolyte can be appropriately selected from known materials.
• the separator include cellulose separators, polyolefin separators, glass fiber separators, and the like.
• the electrolyte may be either liquid or solid, and may be aqueous or non-aqueous, but the electrode for a power storage device of the present invention has practically sufficient performance even when applied to a device using a non-aqueous electrolyte. can be demonstrated.
• the non-aqueous electrolyte include a non-aqueous electrolyte solution prepared by dissolving an electrolyte salt in a non-aqueous organic solvent.
• electrolyte salts include lithium salts such as lithium tetrafluoroborate, lithium hexafluorophosphate, lithium perchlorate, and lithium trifluoromethanesulfonate; tetramethylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, and tetrapropylammonium hexafluoride.
• lithium salts such as lithium tetrafluoroborate, lithium hexafluorophosphate, lithium perchlorate, and lithium trifluoromethanesulfonate
• tetramethylammonium hexafluorophosphate tetraethylammonium hexafluorophosphate
• tetrapropylammonium hexafluoride examples include lithium salts such as lithium tetrafluoroborate, lithium hexafluorophosphate, lithium perchlorate, and lithium triflu
• Examples include quaternary ammonium salts such as fluorophosphate, methyltriethylammonium hexafluorophosphate, tetraethylammonium tetrafluoroborate, and tetraethylammonium perchlorate; lithium imides such as lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide; It will be done.
• quaternary ammonium salts such as fluorophosphate, methyltriethylammonium hexafluorophosphate, tetraethylammonium tetrafluoroborate, and tetraethylammonium perchlorate
• lithium imides such as lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide
• non-aqueous organic solvents examples include alkylene carbonates such as propylene carbonate, ethylene carbonate, and butylene carbonate; dialkyl carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; nitriles such as acetonitrile, and amides such as dimethylformamide. .
• the form of the power storage device is not particularly limited, and cells of various conventionally known forms such as a cylindrical type, a flat wound square type, a laminated square type, a coin type, a flat wound laminate type, and a laminated laminate type are employed. can do.
• the electrode for an electricity storage device of the present invention described above may be punched out into a predetermined disc shape.
• a separator of the same shape impregnated with electrolyte is placed on top of that, and then the electrode is placed on top of the lid. It can be produced by stacking the electrodes for an energy storage device of the present invention with the composite material layer facing down, placing a case and gasket on top, and sealing the electrode with a coin cell caulking machine.
• the electrode When applied to a laminated laminate type, the electrode is formed on a part or the entire surface of the undercoat layer, and the part where the electrode mixture layer is not formed (weld part) is welded to the metal tab.
• the obtained electrode structure may be used.
• the electrode structure may include one or more electrodes, but generally a plurality of positive and negative electrodes are used. It is preferable that the plurality of electrodes for forming the positive electrode are alternately stacked one by one with the plurality of electrodes for forming the negative electrode, and in this case, the above-mentioned separator is interposed between the positive electrode and the negative electrode. It is preferable.
• Metal tabs can be welded at the welded part of the outermost electrode of multiple electrodes, or by sandwiching the metal tab between the welded parts of any two adjacent electrodes among multiple electrodes.
• the material of the metal tab is not particularly limited as long as it is generally used for power storage devices, and examples include metals such as nickel, aluminum, titanium, and copper; stainless steel, nickel alloy, aluminum alloy, and titanium. Examples include alloys such as alloys and copper alloys, but in consideration of welding efficiency, those containing at least one metal selected from aluminum, copper, and nickel are preferred.
• the shape of the metal tab is preferably foil-like, and the thickness thereof is preferably about 0.05 to 1 mm.
• any known method used for welding metals together can be used. Specific examples thereof include TIG welding, spot welding, laser welding, and ultrasonic welding. It is preferable to join the metal tab to the metal tab.
• Ultrasonic welding methods include, for example, placing multiple electrodes between the anvil and the horn, placing a metal tab at the welding area and applying ultrasonic waves to weld them all at once, or welding the electrodes together. Examples include a method of welding first and then welding the metal tab.
• the metal tab and the electrode are welded at the welding portion, but also the plurality of electrodes are ultrasonically welded to each other.
• the pressure, frequency, output, processing time, etc. during welding are not particularly limited, and may be appropriately set in consideration of the material used, the presence or absence of an undercoat layer, the area weight, etc.
• the electrode structure produced as described above is housed in a laminate pack, the above-mentioned electrolyte is injected, and then heat-sealed to obtain a laminate cell.
• Table 1 shows the primary particle diameter and specific surface area of the carbon black used.
• the primary particle diameter was measured using an electron microscope according to ASTM D3849, and the specific surface area was a value obtained using a nitrogen adsorption method according to JIS K6217-2.
• composition for forming conductive binding layer [Example 1-1]
• CB1 solid content ratio 50.0 mass %)
• 39.60 g of pure water Chemipearl S100 (manufactured by Mitsui Chemicals, Ltd., solid content concentration 27 mass % poly(ethylene-methacrylate) Acid) partial sodium salt aqueous dispersion, coal counter particle size less than 0.1 ⁇ m) 6.48 g (solid content 1.75 g, ratio in solid content 50.0% by mass), and 22.17 g of 2-propanol were sequentially added.
• a black liquid mixture was obtained by stirring.
• This black liquid mixture was irradiated with ultrasonic waves at 500 W for 3 minutes using a probe-type ultrasonic irradiator UIP1000hd (manufactured by Hielsher) while stirring under ice-cooling with a magnetic stirrer. After irradiation, the container was removed and the solution was shaken to homogenize it. This ultrasonic treatment was repeated five times to obtain a black uniform dispersion A-1 (solid content concentration 5.0% by mass).
• Example 1-2 A black uniform dispersion A-2 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to CB4.
• Example 1-3 A black uniform dispersion A-3 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to NH-C.
• Example 1-4 A black uniform dispersion A-4 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to NH-F.
• Example 1-5 A black uniform dispersion A-5 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to Denka Black Li-435.
• Example 1-6 In a 100 mL polypropylene bottle container, 1.59 g of CB1 (60.9% by mass of solid content), 0.32 g of NH-C (12.3% by mass of solid content), 40.03 g of pure water, Chemipearl S100 2 .59g (solid content 0.70g, solid content ratio 27% by mass) and 2-propanol 22.17g were sequentially added and stirred to obtain a black liquid mixture, which was then subjected to the same ultrasonic treatment as in Example 1-1. A black uniform dispersion liquid A-6 (solid content concentration 3.9% by mass) was obtained.
• Example 1-7 In a 100 mL polypropylene bottle container, NH-F 2.10 g (solid content ratio 60.0% by mass), pure water 40.55 g, Chemipearl S100 5.19 g (solid content 1.40 g, solid content ratio 40.0 Mass %), 22.17 g of 2-propanol were sequentially added and stirred, and the resulting black mixture was subjected to the same ultrasonic treatment as in Example 1-1 to obtain a black uniform dispersion A-7 ( solid content concentration 5.0% by mass).
• Example 1-8 Dispersion A-7 obtained in Example 1-7 10g [NH-F 0.30g as solid content (solid content ratio 54.5% by mass), Chemipearl S100 solid content 0.20g (solid content ratio 36) 0.50 g (solid content 0.05 g, solid content ratio 9.1% by mass) of Epocross WS-300 (manufactured by Nippon Shokubai Co., Ltd., aqueous solution containing 10% by mass of oxazoline group-containing polymer) was added to The mixture was added and stirred to obtain a black uniform dispersion A-8 (solid content concentration 4.8% by mass).
• Example 1-9 In a 100 mL polypropylene bottle container, NH-F 2.45 g (solid content ratio 70.0% by mass), pure water 44.49 g, Chemipearl S100 3.89 g (solid content 1.05 g, solid content ratio 30.0 Mass %), 22.17 g of 2-propanol were sequentially added and stirred to obtain a black liquid mixture, and the same ultrasonic treatment as in Example 1-1 was performed to obtain a black uniform dispersion liquid (solid content concentration 4.8 mass%) was obtained.
• Epocross WS-300 manufactured by Nippon Shokubai Co., Ltd., containing 10% by mass of an oxazoline group-containing polymer was added to 10g of the above black uniform dispersion liquid, 0.14g as solid content of Chemipearl S100 (solid content ratio: 27.7% by mass)] Aqueous solution) 0.25g (solid content 0.025g, solid content ratio 5.0% by mass) was added and stirred to obtain a black uniform dispersion A-9 (solid content concentration 4.9% by mass).
• Example 1-10 CB1 1.17g (solid content ratio 33.4% by mass), pure water 38.02g, Chemipearl S100 8.64g (solid content 2.33g, solid content ratio 66.6% by mass), 2-propanol 22.17 g was added sequentially and stirred, and the obtained black liquid mixture was subjected to the same ultrasonic treatment as in Example 1-1 to obtain a black uniform dispersion liquid A-10 (solid content concentration 5.0% by mass). Obtained.
• Example 1-11 CB1 2.80g (solid content ratio 80.0% by mass), pure water 42.44g, Chemipearl S100 2.59g (solid content 0.70g, solid content ratio 20.0% by mass), 2-propanol 22.17 g was added sequentially and stirred, and the obtained black liquid mixture was subjected to the same ultrasonic treatment as in Example 1-1 to obtain a black uniform dispersion liquid A-11 (solid content concentration 5.0% by mass). Obtained.
• Example 1-12 In a 100 mL polypropylene bottle container, 1.91 g of Li-435 (solid content ratio 54.5% by mass), pure water 39.94 g, Chemipearl S100 4.71 g (solid content 1.27 g, solid content ratio 36.4 Mass%), 22.17 g of 2-propanol were sequentially added and stirred, and the resulting black mixture was subjected to the same ultrasonic treatment as in Example 1-1, and then treated with Epocross WS-700 (Nippon Shokubai Co., Ltd.). 1.27 g (solid content 0.318 g, solid content ratio 9.1%) of oxazoline group-containing polymer aqueous solution) manufactured by A.I. 5.0% by mass) was obtained.
• Example 1-13 In a 100 mL polypropylene bottle container, 1.59 g of Li-435 (solid content ratio 45.5% by mass), 40.03 g of pure water, Zaixen L (manufactured by Sumitomo Seika Co., Ltd., solid content concentration 24.5% polyester) (Ethylene-acrylic acid) 2-(dimethylamino)ethanol salt aqueous dispersion, coal counter particle size less than 0.1 ⁇ m) 6.49 g (solid content 1.59 g, solid content ratio 45.5% by mass), 2- The black liquid mixture obtained by sequentially adding and stirring 22.17 g of propanol was subjected to the same ultrasonic treatment as in Example 1-1, and then 3.18 g of Epocross WS-300 (solid content 0.318 g, solid content The mixture was stirred at room temperature to obtain a black homogeneous dispersion A-13 (solid content concentration 5.0% by mass).
• Example 1-3 A black uniform dispersion B-3 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to CB2.
• a black uniform dispersion B-4 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to CB7.
• Example 1-5 A black uniform dispersion B-5 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to HS-100.
• Example 1-6 A black uniform dispersion B-6 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to Li-100.
• Example 1-7 A black uniform dispersion B-7 (solid content concentration 5.0% by mass) was obtained using the same method as in Example 1-1 except that CB1 was changed to BP2000.
• Multi-walled carbon nanotube FT6120 manufactured by CNano Technology 0.70g (solid content ratio 50.0% by mass), pure water 43.84g, Chemipearl S100 2.59g (solid content 0.70g, solid content ratio 50)
• the black liquid mixture obtained by sequentially adding and stirring 22.87 g of 2-propanol (22.87 g) and 2-propanol was subjected to the same ultrasonic treatment as in Example 1-1, but the liquid became gel-like and uniformly dispersed. It was not possible to obtain liquid.
• Example 1 except that Chemipearl S100 was changed to Chemipearl S200 (manufactured by Mitsui Chemicals, Ltd., solid content concentration 27% by mass poly(ethylene-methacrylic acid) partial sodium salt aqueous dispersion, coal counter method particle size 0.5 ⁇ m)
• a black uniform dispersion B-10 solid content concentration 5.0% by mass was obtained using the same method as in Example 1.
• CMC ammonium salt (DN-800H manufactured by Daicel Millize Co., Ltd.) (solid content ratio: 22.3% by mass) was added and stirred to form black uniform dispersion B-11 (solid content concentration: 5.0% by mass). ) was obtained.
• Example 2-1 (2) Preparation of undercoat foil [Example 2-1]
• the dispersion liquid A-1 obtained in Example 1-1 was spread on an aluminum foil (manufactured by UACJ Foil Co., Ltd., model number 1N30, thickness 15 um) using a wire bar coater (OSP-30, wet film thickness 30 um, Coating speed: 3 m/min). Thereafter, it was dried in an oven at 120° C. for 10 minutes to form an undercoat layer (conductive binding layer), thereby obtaining undercoat foil C-1 having an undercoat layer on the aluminum foil.
• OSP-30 wire bar coater
• Example 2-2 Undercoat foil C-2 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-2.
• Example 2-3 Undercoat foil C-3 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-3.
• Example 2-4 Undercoat foil C-4 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-4.
• Example 2-5 Undercoat foil C-5 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-5.
• Example 2-6 Undercoat foil C-6 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-6.
• Example 2-7 Undercoat foil C-7 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-7.
• Example 2-8 Undercoat foil C-8 was obtained in the same manner as in Example 2-1, except that dispersion A-1 was changed to dispersion A-8 and the drying temperature in the oven was 50°C.
• Example 2-9 Undercoat foil C-9 was obtained using the same method as in Example 2-1 except that Dispersion A-1 was changed to Dispersion A-9.
• Example 2-10 Undercoat foil C-10 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-10.
• Example 2-11 Undercoat foil C-11 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-11.
• Undercoat foil C-12 was prepared using the same method as in Example 2-1, except that the aluminum foil in Example 2-1 was changed to copper foil (manufactured by Fukuda Metal Foil Powder, electrolytic copper foil, thickness 15 um). (Undercoat layer thickness: 1.5 ⁇ m) was obtained.
• Example 2-13 Undercoat foil C-13 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-12.
• Example 2-14 Undercoat foil C-14 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid A-13.
• Example 2-1 An attempt was made to produce an aluminum foil with an undercoat layer using the same method as in Example 2-1, except that dispersion A-1 was changed to dispersion B-1, but the liquid agglomerated during drying and was not uniform. It was not possible to obtain an aluminum foil with an undercoat layer having a coating surface. Undercoat foil D-1 was obtained in the same manner as in Example 2-1 by changing the aluminum foil described in Example 2-1 to an aluminum foil that had been wiped and washed three times with a nonwoven fabric soaked in hexane. .
• Example 2-2 An attempt was made to produce an aluminum foil with an undercoat layer using the same method as in Example 2-1 except that dispersion A-1 was changed to dispersion B-2, but the liquid agglomerated during drying and it was not uniform. It was not possible to obtain an aluminum foil with an undercoat layer having a coated surface. Undercoat foil D-2 was obtained in the same manner as in Example 2-1 by changing the aluminum foil described in Example 2-1 to an aluminum foil that had been wiped and washed three times with a nonwoven fabric soaked in hexane. .
• Undercoat foil D-3 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid B-3.
• Undercoat foil D-4 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid B-4.
• Undercoat foil D-5 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid B-5.
• Undercoat foil D-6 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid B-6.
• Undercoat foil D-7 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid B-7.
• Undercoat foil D-8 was obtained using the same method as in Example 2-1, except that dispersion liquid A-1 was changed to dispersion liquid B-10.
• ⁇ Coating film area of coating surface, coating film uniformity> The state of the coating film was visually observed immediately after the composition for forming a conductive binding layer (black dispersion) was spread on a metal foil using a wire bar coater and after drying.
• the coating area is determined by dividing the area where a coating film is not formed after drying due to uneven coating of the dispersion liquid or repelling of the dispersion liquid (the area where the surface of the metal foil is exposed) into the uncoated area (the area decreased from the area immediately after spreading).
• the evaluation was based on the following criteria.
• the uniformity of the coating film was evaluated based on the condition of the coating surface after drying according to the following criteria. The evaluation results are shown in Table 2.
• activated carbon electrode For 11.83 g of activated carbon (manufactured by Kuraray Co., Ltd., YP-50F), 0.69 g of acetylene black (manufactured by Denka Co., Ltd.), CMC ammonium salt (manufactured by Daicel Millize Co., Ltd.), DN-800H) 18.33 g of a 1.5% by mass aqueous solution and 22.17 g of pure water were sequentially added with stirring. The obtained black mixture was stirred at 1,400 rpm for 1 minute and at 3,500 rpm using a homomixer (manufactured by Primix Co., Ltd., T.K. Robomix T.K.
• Homomixer MARK II 2.5 type stirring part The mixture was stirred for 1 minute each, and further stirred for 1 minute at a circumferential speed of 20 m/sec using a thin film rotating high speed mixer (Filmix 40-40 model manufactured by Primix Co., Ltd.) to obtain 45.18 g of a black uniform slurry.
• a thin film rotating high speed mixer Frmix 40-40 model manufactured by Primix Co., Ltd.
• To the obtained uniform black slurry 1.69 g of a 48.5% by mass aqueous dispersion of styrene-butadiene rubber (manufactured by JSR Corporation, TRD2001) was added, and Awatori Rentaro (manufactured by Shinky Corporation, ARE-310) was added.
• ⁇ 100°C electrolyte resistance test of EDLC electrode> The activated carbon electrodes prepared above were each cut into 2 cm x 2 cm pieces, and impregnated in 10 g of 1 mol/L tetraethylammonium tetrafluoroborate propylene carbonate solution (hereinafter abbreviated as 1M Et 4 NBF 4 /PC) at 100°C for 8 hours. It was held and allowed to cool.
• the activated carbon electrode was taken out from the solution, washed sequentially with hexane, water, and acetone, and dried by nitrogen blowing. Thereafter, the center part of the activated carbon electrode was bent 180 degrees and opened. The bending marks were visually observed and evaluated according to the following criteria (180° bending test).
• aging was performed by charging and discharging under the following conditions. 0.1 mA/cm 2 charge/discharge, 5 cycles ⁇ 0.2 mA/cm 2 charge/discharge, 5 cycles ⁇ 0.5 mA/cm 2 charge/discharge, 5 cycles ⁇ 1.0 mA/cm 2 charge/discharge, 5 cycles ⁇ 2.
• the obtained EDLC cell had activated carbon electrodes E-1 to E-10, They are shown below as G-1 to G-10 and H-1 to H-6 corresponding to F-1 to F-2 and F-7 to F-10, respectively.
• ⁇ EDLC cell resistance evaluation> AC resistance and direct current resistance (hereinafter abbreviated as DCR) were evaluated as resistance evaluations for the aged EDLC coin cells obtained above.
• AC resistance is measured at a voltage of 1.2 V in the range of 100 mHz to 200 kHz, and the resistance of the semicircular part of the Nyquist plot, which is greatly affected by the current collector foil/electrode interface, is calculated using the R (QR) (QR) W model. It is calculated by and shown in Table 6 as R CT . The resistance until the semicircular part rises is also shown as the solution resistance R S.
• DCR is calculated from the voltage fluctuation value [V]/discharge current value [A] immediately after the end of discharge, and Table 6 shows the resistance values in the region where the value does not change when the current value is changed. In the present invention, a case where both R CT and DCR are 50 ⁇ or less is considered to be a pass.
• G-5 was prepared using the undercoat foil containing the copolymer particles of the present invention, and H-1 was prepared using SBR-CMC, a common binder, or other binders.
• H-5 the resistance increase is smaller even at a high temperature of 70°C and a voltage of 2.5V, and it maintains its function as an undercoat layer under either high temperature or voltage application, or under both conditions. It can be seen that the durability is high.

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• 2023
  • 2023-08-18 JP JP2024545532A patent/JPWO2024053362A1/ja active Pending
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