WO2012099118A1 - Membrane électrolytique polymère, ensemble électrode à membrane et pile à combustible - Google Patents

Membrane électrolytique polymère, ensemble électrode à membrane et pile à combustible Download PDF

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WO2012099118A1
WO2012099118A1 PCT/JP2012/050851 JP2012050851W WO2012099118A1 WO 2012099118 A1 WO2012099118 A1 WO 2012099118A1 JP 2012050851 W JP2012050851 W JP 2012050851W WO 2012099118 A1 WO2012099118 A1 WO 2012099118A1
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polymer electrolyte
group
electrolyte membrane
ion exchange
fine particles
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PCT/JP2012/050851
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English (en)
Japanese (ja)
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寛之 栗田
伸 齋藤
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住友化学株式会社
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    • 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
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/12—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances organic substances
    • H01B1/122—Ionic conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018—Polymeric electrolyte materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018—Polymeric electrolyte materials
    • H01M8/102—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
    • H01M8/1025—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018—Polymeric electrolyte materials
    • H01M8/102—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
    • H01M8/1027—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having carbon, oxygen and other atoms, e.g. sulfonated polyethersulfones [S-PES]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018—Polymeric electrolyte materials
    • H01M8/1041—Polymer electrolyte composites, mixtures or blends
    • H01M8/1046—Mixtures of at least one polymer and at least one additive
    • H01M8/1051—Non-ion-conducting additives, e.g. stabilisers, SiO2 or ZrO2
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a polymer electrolyte membrane, a membrane electrode assembly, and a fuel cell.
  • fuel cells polymer electrolyte fuel cells
  • a fuel cell has a basic configuration of a cell (fuel cell) having a gas diffusion layer for supplying gas serving as power generation fuel to both surfaces of a membrane electrode assembly (hereinafter also referred to as “MEA”).
  • the membrane electrode assembly is a catalyst that promotes a redox reaction between hydrogen and oxygen as power generation fuel on both sides of a polymer electrolyte membrane containing a polymer having ion conductivity (hereinafter referred to as a polymer electrolyte).
  • An electrode called a catalyst layer is formed.
  • fluorine-based polymer electrolytes are mainly studied as polymer electrolyte membranes used in membrane electrode assemblies (see, for example, Patent Document 1), and examples of such fluorine-based polymer electrolytes include Nafion. (A registered trademark of DuPont) is known. Further, it is known that a fluorine-based polymer electrolyte is very expensive and has low heat resistance and membrane strength when applied to a fuel cell that requires high reliability. For this reason, studies have been made on hydrocarbon polymer electrolytes as materials that can be substituted for fluorine polymer electrolytes (see, for example, Patent Documents 2 and 3).
  • the polymer electrolyte membranes disclosed in the above-mentioned patent documents have low operational stability (hereinafter referred to as “long-term stability”) when long-term operation is performed.
  • long-term stability Various factors have been estimated as factors that hinder this long-term stability.
  • the film is deteriorated by a peroxide (for example, hydrogen peroxide) generated during battery operation or a radical generated from the peroxide.
  • the deterioration of the membrane is caused by a decrease in the molecular weight of the polymer electrolyte in the case of a fluorine-based polymer electrolyte membrane and the elution amount of fluorine ions contained in waste water, and in the case of a hydrocarbon-based polymer electrolyte membrane. May be observed.
  • radical resistance improves the durability of the polymer electrolyte membrane against peroxides and radicals. It is said that.
  • radicals generated from peroxide may be simply referred to as “radicals”.
  • antioxidants such as hindered phenolic antioxidants have been widely used for the purpose of suppressing melting deterioration during processing and oxidation deterioration that occurs over time. It has been.
  • antioxidants such as hindered phenolic antioxidants
  • it is insufficient for improving the long-term stability of the solid polymer fuel cell.
  • the present invention has been made in view of such circumstances, and an object thereof is to provide a polymer electrolyte membrane having high durability. Furthermore, to provide a membrane electrode assembly having the above-described polymer electrolyte membrane and having excellent long-term stability, and to providing a fuel cell having this membrane and electrode assembly and having excellent long-term stability. Is one of the purposes.
  • a polymer electrolyte membrane of the present invention comprises a film-like base material formed of a polymer electrolyte, and metal fine particles dispersed in the base material, and the metal
  • the fine particle forming material includes one or more metals selected from the group consisting of noble metals and noble metal alloys, and the metal fine particles are dispersed with a concentration gradient in the thickness direction of the base material.
  • the metal fine particles have a particle size of 500 nm or less.
  • the metal fine particle forming material is at least one of a noble metal or a noble metal alloy selected from the group of noble metals consisting of platinum, gold, palladium, iridium, rhodium and ruthenium, or both. It is desirable to include.
  • the polymer electrolyte membrane is composed of a hydrocarbon polymer electrolyte.
  • the hydrocarbon-based polymer electrolyte includes a block copolymer including a block having an ion exchange group and a block having substantially no ion exchange group.
  • a metal layer is laminated on the surface of the film-shaped base material formed of the polymer electrolyte, and a voltage is applied from both sides of the base material and the metal layer to apply the base. It is desirable to include the metal fine particles deposited inside the material.
  • the metal layer is formed by physical vapor deposition.
  • the metal layer is preferably formed by applying a liquid containing metal fine particles to the surface of the polymer electrolyte membrane.
  • the membrane electrode assembly of the present invention includes the above-described polymer electrolyte membrane, and an anode catalyst layer and a cathode catalyst layer that sandwich the polymer electrolyte membrane.
  • the maximum value of the concentration of the metal fine particles is on the cathode catalyst layer side with respect to the center in the film thickness direction of the polymer electrolyte membrane.
  • the fuel cell of the present invention has the above-described polymer electrolyte membrane.
  • the first aspect of the present invention is a film-like base material formed of a polymer electrolyte, Metal fine particles dispersed in the base material,
  • the metal fine particle forming material contains one or more metals selected from the group consisting of noble metals and noble metal alloys, and the metal fine particles are dispersed with a concentration gradient in the thickness direction of the base material. It is a molecular electrolyte membrane.
  • a second aspect of the present invention is the polymer electrolyte membrane according to the first aspect, wherein the concentration of the metal fine particles has a maximum value.
  • a third aspect of the present invention is the polymer electrolyte membrane according to the first or second aspect, wherein the metal fine particles have a particle diameter of 500 nm or less.
  • the metal fine particle forming material is selected from a noble metal group consisting of platinum, gold, palladium, iridium, rhodium and ruthenium, A polymer electrolyte membrane containing one or both of one kind of noble metal and noble metal alloy.
  • the polymer electrolyte is a polymer electrolyte membrane made of a hydrocarbon polymer electrolyte.
  • a block copolymer according to the fifth aspect wherein the hydrocarbon-based polymer electrolyte includes a segment having an ion exchange group and a segment having substantially no ion exchange group.
  • a polymer electrolyte membrane containing a polymer is provided.
  • a metal layer is laminated on a surface of a film-shaped base material formed of the polymer electrolyte, and the base material and the base material
  • the polymer electrolyte membrane includes the metal fine particles deposited inside the base material by applying a voltage from both sides of the metal layer.
  • An eighth aspect of the present invention is the polymer electrolyte membrane according to the seventh aspect, wherein the metal layer is formed by physical vapor deposition.
  • a ninth aspect of the present invention is the polymer electrolyte membrane according to the seventh aspect, wherein the metal layer is formed by applying a liquid containing metal fine particles to the surface of the base material.
  • a membrane electrode junction comprising the polymer electrolyte membrane according to any one of the first to ninth aspects, and an anode catalyst layer and a cathode catalyst layer sandwiching the polymer electrolyte membrane. Is the body.
  • An eleventh aspect of the present invention is the membrane electrode assembly according to the tenth aspect, wherein the maximum value of the concentration of the metal fine particles is closer to the cathode catalyst layer side than the center in the film thickness direction of the polymer electrolyte membrane. It is.
  • a twelfth aspect of the present invention is a fuel cell having the membrane electrode assembly according to the tenth or eleventh aspect.
  • a highly durable polymer electrolyte membrane can be obtained.
  • the membrane electrode assembly excellent in long-term stability can be obtained by using such a polymer electrolyte membrane.
  • a fuel cell having excellent long-term stability can be obtained.
  • achieve such high durability can be manufactured easily.
  • FIG. 1 is an electron micrograph showing the inside of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 1 is an electron micrograph showing the inside of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 2 is a part of a process chart showing a production process of a polymer electrolyte membrane according to a preferred embodiment of the present invention.
  • FIG. 1 is a longitudinal sectional view of a cell of a fuel cell having a membrane electrode assembly according to a preferred embodiment of the present invention (hereinafter sometimes simply referred to as a fuel cell).
  • the fuel cell 10 includes a membrane electrode assembly (MEA) 20 composed of a polymer electrolyte membrane 12 and a pair of catalyst layers 14a and 14b sandwiched therebetween.
  • MEA membrane electrode assembly
  • a structure composed of the membrane electrode assembly 20 and the gas diffusion layers 16a and 16b may be generally called a membrane electrode-gas diffusion layer assembly (MEGA).
  • MEGA membrane electrode-gas diffusion layer assembly
  • the anode catalyst layer 14 a and the cathode catalyst layer 14 b are layers that function as electrode layers in the fuel cell 10.
  • the anode catalyst layer 14a and the cathode catalyst layer 14b include an electrode catalyst and a polymer electrolyte having proton conductivity such as perfluoroalkyl sulfonic acid resin.
  • the electrode catalyst is not particularly limited as long as it can activate a redox reaction with hydrogen or oxygen, and a known electrode catalyst can be used, but platinum or platinum-based alloy fine particles are used as a catalyst. It is preferable to use it.
  • the fine particles of platinum or platinum-based alloys are often used by being supported on particulate or fibrous carbon such as activated carbon or graphite.
  • the gas diffusion layers 16a and 16b are layers having a function of promoting the diffusion of the raw material gas into the catalyst layers 14a and 14b.
  • the gas diffusion layers 16a and 16b are preferably made of a porous material having electron conductivity.
  • a porous carbon nonwoven fabric or carbon paper is preferable because the raw material gas can be efficiently transported to the catalyst layers 14a and 14b.
  • Separator 18a, 18b is formed with the material which has electronic conductivity.
  • Examples of the material having electron conductivity include carbon, resin mold carbon, titanium, and stainless steel.
  • the fuel cell manufactured in this way can be used in various forms using, for example, hydrogen gas, reformed hydrogen gas, and methanol as fuel.
  • the membrane electrode assembly 20 shown in FIG. 10 has a pair of catalyst layers 14a and 14b that sandwich the polymer electrolyte membrane 12 as described above.
  • FIG. 2 is a transmission electron micrograph showing the inside of the polymer electrolyte membrane 12.
  • the polymer electrolyte membrane 12 of the present embodiment includes a base material 12X using a polymer electrolyte as a forming material and metal fine particles 13A dispersed in the base material 12X.
  • the metal fine particles 13A are shown as black spots in the photograph of FIG.
  • polymer electrolyte constituting the base material of the polymer electrolyte membrane 12 examples include hydrocarbon polymer electrolytes and fluorine polymer electrolytes as described below. Further, as components other than the polymer electrolyte constituting the base material 12X, additives such as plasticizers, stabilizers, mold release agents, water retention agents and the like used for ordinary polymers can be mentioned.
  • Hydrocarbon polymer electrolyte First, a hydrocarbon polymer electrolyte that can be used for the polymer electrolyte membrane in one embodiment of the present invention will be described.
  • the hydrocarbon polymer electrolyte means a polymer electrolyte having a halogen atom content of 15% by mass or less in terms of the mass content ratio of elements constituting the polymer electrolyte.
  • a hydrocarbon-based polymer electrolyte is more preferable because it has an advantage that it is cheaper than the above-mentioned fluorine-based polymer electrolyte.
  • Particularly preferred hydrocarbon polymer electrolytes are hydrocarbon polymer electrolytes that do not substantially contain halogen atoms. Such hydrocarbon polymer electrolytes do not generate hydrogen halide during the operation of the fuel cell. There is no danger of corrosion and corrosion of other components.
  • the “hydrocarbon polymer electrolyte” mentioned here may contain a hetero atom.
  • the hydrocarbon-based polymer electrolyte is preferably a polymer having an ion exchange group.
  • the reason is that when a polymer electrolyte membrane for a fuel cell is obtained using a polymer electrolyte having an ion exchange group, the ion conductivity of the polymer electrolyte membrane is improved.
  • the ion exchange group examples include an acidic ion exchange group (that is, a cation exchange group) or a basic ion exchange group (that is, an anion exchange group). From the viewpoint of obtaining high proton conductivity, the ion exchange group is preferably a cation exchange group. By using a polymer electrolyte having a cation exchange group, a fuel cell having further excellent power generation performance can be obtained.
  • the cation exchange group examples include a sulfo group (—SO 3 H), a carboxyl group (—COOH), a phosphono group (—PO 3 H 2 ), a sulfonylimide group (—SO 2 NHSO 2 —), a phenolic hydroxyl group, and the like. Is mentioned. Among these, as the cation exchange group, a sulfo group or a phosphono group is more preferable, and a sulfo group is particularly preferable. These ion exchange groups may be partially or wholly exchanged with metal ions or quaternary ammonium ions to form a salt, but when used as a fuel cell member, It is preferred that substantially all are in the free acid form. When the ion exchange group is in the form of a free acid, there is an advantage that the preparation of the polymer electrolyte solution becomes easier in the production of the laminated film described later.
  • ion exchange groups may be introduced into either or both of the main chain or side chain of the polymer electrolyte, but are preferably introduced into the main chain.
  • the introduction amount of the ion exchange group can be represented by an ion exchange group capacity which is the number of ion exchange groups per unit mass of the polymer electrolyte.
  • the “ion exchange group capacity” is a value [milli equivalent / g dry resin] defined by the number of equivalents of ion exchange groups contained in 1 g of dry resin in the polymer electrolyte constituting the polymer electrolyte membrane.
  • meq / g meq / g
  • dry resin refers to a resin in which the polymer electrolyte is maintained at a temperature equal to or higher than the boiling point of water, the mass decrease hardly occurs, and the change in mass with time converges to a substantially constant value.
  • the amount of ion exchange groups introduced is preferably 0.5 meq / g or more and 6.0 meq / g or less in terms of ion exchange capacity; 1.0 meq / g or more and 6.0 meq. / G or less; more preferably 2.0 meq / g or more and 5.5 meq / g or less; and most preferably 2.7 meq / g or more and 5.0 meq / g or less.
  • the polymer electrolyte membrane to be obtained has better proton conductivity and water resistance, both of which are excellent because the function as a polymer electrolyte membrane used in a fuel cell is excellent.
  • polymer electrolyte having a suitable ion exchange group examples include polymer electrolytes represented by the following (A) to (F).
  • A a polymer electrolyte in which an ion exchange group is introduced into a polymer whose main chain is an aliphatic hydrocarbon
  • B a polymer electrolyte in which an ion exchange group is introduced into a polymer in which the main chain is composed of an aliphatic hydrocarbon and a part of the hydrogen atoms of the main chain is substituted with fluorine atoms
  • C a polymer electrolyte in which an ion exchange group is introduced into a polymer having a main chain having an aromatic ring
  • D a polymer electrolyte in which an ion exchange group is introduced into a polymer whose main chain has an inorganic unit structure such as a siloxane group or a phosphazene group;
  • a polymer electrolyte whose ion exchange group is a sulfo group is mainly exemplified, but a polymer electrolyte in which this sulfo group is replaced with another ion exchange group may be used.
  • polymer electrolyte (A) examples include polyvinyl sulfonic acid, polystyrene sulfonic acid, poly ( ⁇ -methylstyrene) sulfonic acid, and the like.
  • polymer electrolyte (B) a polymer produced by copolymerization of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer described in JP-A-9-102322 has a main chain, and a sulfo group.
  • a sulfonic acid type polystyrene-graft-ethylene-tetrafluoroethylene copolymer (ETFE) having a hydrocarbon chain having a side chain as a side chain and a copolymerization mode of graft polymerization is exemplified.
  • a copolymer of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer obtained by the method described in US Pat. No. 4,012,303 or US Pat.
  • sulfonic acid type poly (trifluorostyrene) -graft-ETFE in which a solid polymer electrolyte is prepared by graft polymerization of, ⁇ , ⁇ -trifluorostyrene and introducing a sulfo group into the polymer.
  • the polymer electrolyte (C) may be a polymer electrolyte containing a hetero atom such as an oxygen atom in the main chain.
  • a polymer electrolyte examples include polyether ketone, polyether ether ketone, polysulfone, polyether sulfone, polyether ether sulfone, poly (arylene ether), polyimide, poly ((4-phenoxybenzoyl) -1, Examples thereof include polymer electrolytes each having a sulfo group introduced into each of homopolymers such as 4-phenylene) and polyphenylquinoxalen.
  • the polymer electrolyte (C) may be a compound in which the main chain is interrupted by a heteroatom such as an oxygen atom.
  • Such polymer electrolytes are disclosed in JP-A-9-110882 and J.P. Appl. Polym. Sci. 18, 1969 (1974).
  • Examples of the polymer electrolyte (D) include a polymer electrolyte in which a sulfo group is introduced into polyphosphazene. These are Polymer Prep. , 41, no. 1, 70 (2000).
  • the polymer electrolyte (E) may be any of a random copolymer having a sulfo group introduced therein, an alternating copolymer having a sulfo group introduced therein, or a block copolymer having a sulfo group introduced therein. .
  • polymer electrolyte (F) examples include polybenzimidazole into which phosphoric acid is introduced as described in JP-A-11-503262.
  • the polymer electrolyte used for the polymer electrolyte membrane in one embodiment of the present invention is preferably a copolymer composed of a structural unit having an ion exchange group and a structural unit having no ion exchange group.
  • the polymer electrolyte membrane prepared by the method described later using the resulting polymer electrolyte exhibits good proton conductivity and water resistance, and is advantageous for fuel cells.
  • the copolymerization mode of the two kinds of structural units may be any of random copolymerization, block copolymerization, graft copolymerization or alternating copolymerization, and these copolymerization modes are combined. Also good.
  • the hydrocarbon polymer electrolyte particularly a hydrocarbon polymer electrolyte having an aromatic ring in the main chain (that is, the above-mentioned (C) a hydrocarbon-based polymer electrolyte) is preferred; and further has an aromatic ring constituting the main chain, and is directly bonded to the aromatic ring or indirectly through another atom or atomic group Hydrocarbon polymer electrolytes having bound ion exchange groups are preferred.
  • it may have aromatics constituting the main chain, and may further have side chains having aromatic rings, and directly bonded to either the aromatic ring constituting the main chain or the aromatic ring of the side chain.
  • An aromatic polymer electrolyte having an ion exchange group is preferred.
  • aromatic polymer electrolytes include polymer electrolytes having a structural unit having an ion exchange group in the molecular structure and a structural unit having no ion exchange group.
  • Examples of the structural unit having an ion exchange group include structures represented by the following formulas (11a) to (14a).
  • Ar 1 to Ar 9 are the same or different and each represents a divalent aromatic group which may have a side chain having an aromatic ring in the main chain and further having an aromatic ring; A group is directly bonded to at least one of the aromatic ring of the main chain or the aromatic ring of the side chain; Z and Z ′ are the same or different and each represents a group represented by —CO— or a group represented by —SO 2 —; X, X ′, and X ′′ are the same or different —O— Y represents a direct bond or a group represented by the following formula (15); p represents 0, 1 or 2; q and r represent Each represents the same or different and represents 1, 2 or 3.)
  • examples of the structural unit having no ion exchange group include structures represented by the following formulas (11b) to (14b).
  • Ar 11 to Ar 19 are the same or different and each represents a divalent aromatic group which may have a substituent as a side chain;
  • Z and Z ′ are the same or different and each represents a group represented by —CO— or a group represented by —SO 2 —;
  • X, X ′ and X ′′ are the same or different —O— Or
  • Y represents a direct bond or a group represented by the following formula (15);
  • p ′ represents 0, 1 or 2
  • q ′ And r ′ are the same or different and represent 1, 2 or 3.
  • R 1 and R 2 are the same or different and each is a hydrogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted carbon group having 1 to 20 alkoxy groups, optionally substituted aryl groups having 6 to 20 carbon atoms, optionally substituted aryloxy groups having 6 to 20 carbon atoms, or substituted groups.
  • Ar 1 to Ar 9 represent a divalent aromatic group.
  • the divalent aromatic group include divalent monocyclic aromatic hydrocarbon groups such as 1,3-phenylene group and 1,4-phenylene group; 1,3-naphthalenediyl group, 1,4- Divalent condensed rings such as naphthalenediyl group, 1,5-naphthalenediyl group, 1,6-naphthalenediyl group, 1,7-naphthalenediyl group, 2,6-naphthalenediyl group, 2,7-naphthalenediyl group, etc.
  • Ar 1 to Ar 9 in the formulas (11a) to (14a) are preferably divalent monocyclic aromatic hydrocarbon groups such as 1,3-phenylene group and 1,4-phenylene group; -Naphthalenediyl group, 1,4-naphthalenediyl group, 1,5-naphthalenediyl group, 1,6-naphthalenediyl group, 1,7-naphthalenediyl group, 2,6-naphthalenediyl group, 2,7-naphthalene
  • a divalent condensed ring aromatic hydrocarbon group such as a diyl group; and more preferably a divalent monocyclic aromatic hydrocarbon group.
  • the hydrogen atom on the aromatic ring of the aromatic group represented by Ar 1 to Ar 9 in formulas (11a) to (14a) is an optionally substituted alkyl group having 1 to 20 carbon atoms, An optionally substituted alkoxy group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 20 carbon atoms, and an optionally substituted carbon group having 6 to 20 carbon atoms.
  • the aryloxy group may be substituted with an acyl group having 2 to 21 carbon atoms which may have a substituent.
  • the aromatic groups represented by Ar 1 to Ar 9 in formulas (11a) to (14a) have at least one ion exchange group in the aromatic ring.
  • Specific examples and preferred examples of the ion exchange group can be the same as those described above.
  • These ion exchange groups may be introduced into one or both of the main chain and the side chain of the polymer electrolyte, but are preferably introduced into the aromatic ring of the main chain.
  • an acidic ion exchange group is preferable as described above, and among the acidic ion exchange groups, a sulfo group or a phosphono group is more preferable, and a sulfo group is particularly preferable.
  • Ar 110 , Ar 120 , and Ar 130 each independently represent a divalent aromatic group, and the hydrogen atom on the aromatic ring may be substituted with a fluorine atom.
  • Y 000 represents —CO—, —SO 2 —, —SO—, —CONH—, —COO— , — (CF 2 ) u000 — (u000 is an integer of 1 to 10), —C (CF 3 ) 2 - or a direct bond are shown;
  • Z 000 is, -O -, - S-, a direct bond, -CO -, - SO 2 - , - SO -, - (CH 2) k000 - (k000 1-10
  • R 110 represents a direct bond, —O (CH 2 ) p000 —, —O (CF 2 ) p000 —, — (CH 2 ) p000 —, or —C (CH 3 ) 2 — - (CF 2) p000
  • Ar 110 , Ar 120 and Ar 130 in the formula (14a-1) represent a divalent aromatic group.
  • Examples of such a divalent aromatic group include the same divalent aromatic groups as Ar 1 to Ar 9 in formulas (11a) to (14a).
  • R 120 and R 130 each independently represent a hydrogen atom, an alkali metal atom or a hydrocarbon group.
  • the alkali metal atom include lithium, sodium, potassium, rubidium, and cesium.
  • the hydrocarbon group may have a heterocyclic group, and examples of such a hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, a tert-butyl group, an iso group.
  • heptyl group bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl group, 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolanemethyl group, cyclohexylmethyl group, adamantylmethyl
  • a straight-chain hydrocarbon group such as a bicyclo [2.2.1] heptylmethyl group, a branched hydrocarbon group, Cyclic hydrocarbon group, and hydrocarbon group having a heterocyclic group.
  • R 120 and R 130 are preferably hydrogen atoms.
  • the structural unit represented by the above formula (14a-1) is preferably a structural unit represented by the following formula (14a-2).
  • Y 001 is —CO—, —SO 2 —, —SO—, —CONH—, —COO—, — (CF 2 ) h — (where h is 1 to 10).
  • An integer) and at least one structure selected from the group consisting of —C (CF 3 ) 2 —;
  • Z 001 represents a direct bond or — (CH 2 ) g — (where g is 1 to And an at least one structure selected from the group consisting of —C (CH 3 ) 2 —, —O—, —S—, —CO— and —SO 2 —;
  • Ar 001 represents — An aromatic group having a substituent represented by SO 3 H, —O (CH 2 ) p SO 3 H or —O (CF 2 ) p SO 3 H;
  • p represents an integer of 1 to 12;
  • n001 represents an integer of 0 to 10;
  • k001 represents an
  • structural unit having an ion exchange group represented by the above formula (14a-2) include structural units represented by the following formulas (4a-13) to (4a-20).
  • Ar 11 to Ar 19 each independently represent a divalent aromatic group.
  • divalent aromatic groups include divalent monocyclic aromatic hydrocarbon groups such as 1,3-phenylene group and 1,4-phenylene group; 1,3-naphthalenediyl group, 1 , 4-Naphthalenediyl group, 1,5-naphthalenediyl group, 1,6-naphthalenediyl group, 1,7-naphthalenediyl group, 2,6-naphthalenediyl group, 2,7-naphthalenediyl group, etc.
  • Ar 11 to Ar 19 in the formulas (11b) to (14b) are preferably divalent monocyclic aromatic hydrocarbon groups such as 1,3-phenylene group and 1,4-phenylene group, 1,3 -Naphthalenediyl group, 1,4-naphthalenediyl group, 1,5-naphthalenediyl group, 1,6-naphthalenediyl group, 1,7-naphthalenediyl group, 2,6-naphthalenediyl group, 2,7-naphthalene It is a divalent fused ring aromatic hydrocarbon group such as a diyl group, and more preferably a divalent monocyclic aromatic hydrocarbon group.
  • the hydrogen atom on the aromatic ring of the aromatic group represented by Ar 11 to Ar 19 is a fluorine atom, a formyl group, a cyano group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, An optionally substituted alkoxy group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 20 carbon atoms, and an optionally substituted carbon group having 6 to 20 carbon atoms.
  • the aryloxy group may be substituted with an acyl group having 2 to 21 carbon atoms which may have a substituent.
  • the “optionally substituted” substituent here does not include the ion exchange group.
  • divalent aromatic groups (the aromatic groups represented by Ar 1 to Ar 9 in the formulas (11a) to (14a) and the Ar 11 to Ar 19 in the formulas (11b) to (14b) are represented.
  • substituent of the aromatic group are as follows.
  • Examples of the optionally substituted alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, n -Pentyl group, 2,2-dimethylpropyl group, cyclopentyl group, n-hexyl group, cyclohexyl group, 2-methylpentyl group, 2-ethylhexyl group, nonyl group, dodecyl group, hexadecyl group, octadecyl group, icosyl group, etc.
  • Alkyl groups having 1 to 20 carbon atoms include fluorine atom, hydroxyl group, nitrile group, amino group, methoxy group, ethoxy group, isopropyloxy group, phenyl group, naphthyl group, phenoxy group, naphthyloxy group, etc. Examples thereof include an alkyl group which is substituted and has a total carbon number of 20 or less.
  • Examples of the optionally substituted alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, sec-butyloxy group, tert- Butyloxy, isobutyloxy, n-pentyloxy, 2,2-dimethylpropyloxy, cyclopentyloxy, n-hexyloxy, cyclohexyloxy, 2-methylpentyloxy, 2-ethylhexyloxy, dodecyl
  • An alkoxy group having 1 to 20 carbon atoms such as an oxy group, a hexadecyloxy group, an icosyloxy group; and these groups include a fluorine atom, a hydroxyl group, a nitrile group, an amino group, a methoxy group, an ethoxy group, an isopropyloxy group, and a phenyl
  • aryl groups such as a phenyl group, a naphthyl group, a phenanthrenyl group, and an anthracenyl group; and these groups include a fluorine atom, a hydroxyl group, and a nitrile.
  • Group, amino group, methoxy group, ethoxy group, isopropyloxy group, phenyl group, naphthyl group, phenoxy group, naphthyloxy group and the like are substituted, and aryl groups having a total carbon number of 20 or less can be mentioned.
  • aryloxy group having 6 to 20 carbon atoms which may have a substituent include aryloxy groups such as a phenoxy group, a naphthyloxy group, a phenanthrenyloxy group, and an anthracenyloxy group; Are substituted with fluorine atom, hydroxyl group, nitrile group, amino group, methoxy group, ethoxy group, isopropyloxy group, phenyl group, naphthyl group, phenoxy group, naphthyloxy group, etc.
  • a certain aryloxy group is mentioned.
  • Examples of the optionally substituted acyl group having 2 to 21 carbon atoms include acetyl group, propionyl group, butyryl group, isobutyryl group, pivaloyl group, benzoyl group, 1-naphthoyl group, and 2-naphthoyl group.
  • an acyl group having a total carbon number of 21 or less isopropyloxy group, phenyl group, naphthyl group, phenoxy group, naphthyloxy group, etc.
  • the substituent is an aryl group such as a phenyl group, a naphthyl group, a phenanthrenyl group or an anthracenyl group; an aryloxy group such as a phenoxy group, a naphthyloxy group, a phenanthrenyloxy group or an anthracenyloxy group; a benzoyl group, 1 -A substituent having an aromatic ring such as an acyl group having an aromatic ring such as a naphthoyl group or a 2-naphthoyl group tends to improve the heat resistance of the polymer, and a more practical fuel cell member can be obtained. Therefore, it is preferable.
  • a polyelectrolyte including a polymer having an acyl group having an aromatic ring as a substituent two structural units having the acyl group are adjacent to each other, and the acyl groups in the two structural units are bonded to each other.
  • the structure may change by causing a rearrangement reaction after the groups are bonded to each other. Whether or not such a structural change has occurred can be confirmed, for example, by measuring a 13 C-nuclear magnetic resonance spectrum.
  • One of the preferable elements of the hydrocarbon-based polymer electrolyte in the present invention is a polymer electrolyte having a halogen atom content of 15% by mass or less in terms of the mass content ratio of elements constituting the polymer electrolyte.
  • Such hydrocarbon polymer electrolytes have the advantage of being inexpensive compared to the fluorine polymer electrolytes described above, and therefore more preferred, particularly preferred hydrocarbon polymer electrolytes substantially contain halogen atoms. This hydrocarbon polymer electrolyte does not generate hydrogen halide during the operation of the fuel cell and does not corrode other members.
  • the hydrocarbon-based polymer electrolyte includes a structural unit having an ion exchange group and a structural unit not having an ion exchange group, and a dense phase of the structural unit having an ion exchange group forms a continuous phase in the film thickness direction. If it can be formed, it is preferable because there is an advantage that a polymer electrolyte membrane having more excellent proton conductivity can be obtained.
  • suitable polymer electrolytes are represented by the structural units having an ion exchange group composed of the structural units represented by the formulas (11a) to (14a) and the formulas (11b) to (14b). And a structural unit having no ion-exchange group.
  • a polymer electrolyte can be obtained as a copolymer starting from monomers or oligomers corresponding to a structural unit having an ion exchange group and a structural unit having no ion exchange group.
  • examples of the combination of a structural unit having an ion exchange group and a structural unit having no ion exchange group include the combinations shown in ⁇ A> to ⁇ M> in Table 1 below.
  • the structure of the polymer electrolyte preferably used in the present invention is more preferably ⁇ B>, ⁇ C>, ⁇ D>, ⁇ G>, ⁇ H>, ⁇ I>, ⁇ J>, ⁇ L>.
  • ⁇ M> even more preferably ⁇ G>, ⁇ H>, ⁇ L> or ⁇ M>; and particularly preferably ⁇ G>, ⁇ H> or ⁇ L>.
  • suitable copolymers include one or more structural units selected from the group of structural units having ion exchange groups shown below, and a group of structural units having no ion exchange groups shown below. And a copolymer composed of one or more structural units.
  • the ion exchange group in the repeating unit which has an ion exchange group is illustrated by the suitable sulfo group.
  • any of the above-described ion exchange groups may be employed instead of the sulfo group.
  • these structural units may be directly bonded to each other, or may be connected to each other with an appropriate atom or atomic group.
  • an atom or an atomic group for bonding structural units here a divalent aromatic group, an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or a divalent group formed by combining these is used. Can be mentioned.
  • r000 represents 0 or an integer of 1 or more; r000 is preferably 100 or less, more preferably 1 or more and 80 or less.
  • the formulas representing the structural unit having an ion exchange group include the formulas (4a-1), (4a-2), (4a-3), (4a-4), (4a-5), ( 1a or more selected from the group consisting of 4a-6), (4a-7), (4a-8), (4a-9), (4a-10), (4a-11), and (4a-12)
  • the structural unit is preferred.
  • one or more structural units selected from the group consisting of formulas (4a-10), (4a-11), and (4a-12) are more preferred, and formula (4a-11) or (4a-12) Is particularly preferred.
  • a polymer electrolyte having a segment containing such a structural unit particularly a polymer electrolyte having a segment containing such a structural unit as a repeating unit (segment having an ion exchange group) has a polyarylene structure. Therefore, the chemical stability tends to be relatively good.
  • the formulas representing the structural unit having no ion exchange group include formulas (4b-1), (4b-2), (4b-3), (4b-4), (4b-5), (4b- 6), (4b-7), (4b-8), (4b-9), (4b-10), (4b-11), (4b-12), (4b-13), and (4b-14) And one or more structural units selected from the group consisting of Similarly, one or more structural units selected from the group consisting of formulas (4b-2), (4b-3), (4b-10), (4b-13), and (4b-14) are more preferred; One or more structural units selected from the group consisting of formulas (4b-2), (4b-3), and (4b-14) are particularly preferred.
  • the polymer electrolyte according to the present invention is a polymer electrolyte having a structural unit having an ion exchange group and a structural unit not having an ion exchange group, and the copolymerization mode of these two structural units is random copolymerization.
  • Preferred are random copolymerization, block copolymerization, and graft copolymerization; more preferred are random copolymerization and block copolymerization; and particularly preferred is block copolymerization.
  • a segment mainly composed of a structural unit having an ion exchange group (segment having an ion exchange group) and a segment mainly composed of a structural unit not having an ion exchange group (that is, substantially having an ion exchange group) And a copolymer having a segment not included).
  • a block copolymer has an advantage that a polymer electrolyte membrane having more excellent proton conductivity can be obtained by forming a continuous phase in the film thickness direction with a dense phase having segments having ion exchange groups.
  • combinations of structural units constituting a segment having a suitable ion exchange group and structural units constituting a segment having substantially no ion exchange group are shown in ⁇ A> to ⁇ M> in Table 2 below. A combination of segments can be mentioned.
  • formulas (4a-1), (4a-2), (4a-3), (4a-4) represent the structural units used for the repeating units constituting the segment having an ion exchange group.
  • (4a-5), (4a-6), (4a-7), (4a-8), (4a-9), (4a-10), (4a-11) and (4a-12) One or more structural units selected from the group are preferred; one or more structural units selected from the group consisting of the formulas (4a-10), (4a-11), and (4a-12) are more preferred; 4a-11) or (4a-12) is particularly preferred.
  • the block copolymer according to the present invention is that the main chain of the segment having an ion exchange group has a polyarylene structure formed by substantially directly connecting a plurality of aromatic rings.
  • the structural unit of such a segment preferably the above formulas (4a-10), (4a-11), (4a-12), (4a-13), (4a-14), (4a-15), One or more structural units selected from the group consisting of (4a-16), (4a-17), (4a-18), (4a-19) and (4a-20) are preferred, and are represented by the formula (4a-10) , One or more structural units selected from the group consisting of (4a-11) and (4a-12) are more preferred, and formula (4a-11) or (4a-12) is particularly preferred.
  • a polymer electrolyte having a segment including a repeating unit composed of such a structural unit that is, a segment having an ion exchange group
  • a polymer electrolyte having a segment composed of such a repeating unit has excellent ion conductivity. Since this segment has a polyarylene structure, chemical stability tends to be relatively good.
  • the “polyarylene structure” is a form in which the aromatic rings constituting the main chain are substantially directly bonded to each other. Specifically, the total number of bonds between the aromatic rings is 100. %, The direct bond ratio is preferably 80% or more, more preferably 90% or more, and still more preferably 95% or more.
  • bonded by the direct bond are forms in which aromatic rings are couple
  • the formulas representing the structural units used for the repeating units constituting the segment having no ion exchange group include the formulas (4b-1), (4b-2), (4b-3), (4b-4), (4b -5), (4b-6), (4b-7), (4b-8), (4b-9), (4b-10), (4b-11), (4b-12), (4b-13) ) And (4b-14) are preferred; one or more structural units selected from the group consisting of: (4b-2), (4b-3), (4b-9), (4b-10), (4b- More preferred is one or more structural units selected from the group consisting of 13) and (4b-14); consisting of formulas (4b-2), (4b-3), (4b-13) and (4b-14) Even more preferred are one or more structural units selected from the group; formulas (4b-2), (4b-3) and ( b-14) 1 or more structural units selected from the group consisting of especially preferred.
  • the segment having an ion exchange group and the segment having substantially no ion exchange group may be directly bonded or may be connected by an appropriate atom or atomic group.
  • atoms or atomic groups connecting the segments a divalent aromatic group, an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or a divalent group formed by combining these is given. be able to.
  • divalent aromatic group include the same divalent aromatic groups as Ar 1 to Ar 9 in formulas (11a) to (14a).
  • Suitable block copolymers include a segment containing one or more structural units selected from the group of structural units having an ion exchange group shown above (ie, a segment having an ion exchange group), and A block copolymer comprising a segment containing one or more structural units selected from the group of structural units having no ion exchange group shown above (that is, a segment having substantially no ion exchange group). Can be mentioned.
  • the “segment having an ion exchange group” means that the ion exchange group is a segment containing an average of 0.5 or more per structural unit constituting the segment. It is more preferable that one or more ion exchange groups are contained on an average per unit.
  • the “segment substantially having no ion exchange group” means that the ion exchange group is a segment having an average of less than 0.5 per structural unit constituting the segment, More preferably, the number of ion exchange groups per unit is 0.1 or less on average; more preferably 0.05 or less on average.
  • a block copolymer in a form in which a segment having an ion exchange group and a segment having substantially no ion exchange group are bonded by a direct bond or bonded by an appropriate atom or atomic group. is there.
  • the degree of polymerization of the segment composed of one or more structural units selected from the structural units represented by the above formulas (11a) to (14a) is 2 or more, preferably 3 or more; more preferably 5 or more; Further preferred.
  • the polymerization degree of the segment is preferably 1000 or less; preferably 500 or less. If the degree of polymerization is 2 or more, preferably 5 or more, sufficient proton conductivity is expressed as a polymer electrolyte for a fuel cell, and if the degree of polymerization is 1000 or less, the advantage is that manufacture is easier. There is. That is, the polymerization degree of the segment is preferably 2 or more and 1000 or less; more preferably 5 or more and 1000 or less; more preferably 5 or more and 500 or less; and most preferably 10 or more and 500 or less.
  • the degree of polymerization of a segment composed of one or more structural units selected from the structural units represented by formulas (11b) to (14b) is 1 or more, preferably 2 or more; more preferably 3 or more. Further, the polymerization degree of the segment is preferably 100 or less; more preferably 90 or less; and still more preferably 80 or less. If the degree of polymerization is within such a range, it is preferable as a polymer electrolyte for a fuel cell because it has sufficient mechanical strength and is easy to produce. That is, the polymerization degree of the segment is preferably 1 or more and 100 or less; more preferably 2 or more and 90 or less; and further preferably 3 or more and 80 or less.
  • the molecular weight of the hydrocarbon-based polymer electrolyte used in the present invention is preferably 5000 to 1,000,000, more preferably 10,000 to 800,000, more preferably 10,000 to 600,000 in terms of polystyrene-reduced number average molecular weight. More preferably, it is more preferably 15,000 to 400,000.
  • a polymer electrolyte having a molecular weight in such a range a polymer electrolyte membrane prepared by a method described later tends to stably maintain the shape of the membrane.
  • the number average molecular weight is measured by gel permeation chromatography (GPC).
  • fluorine-type polymer electrolyte which can be used for the polymer electrolyte membrane in one Embodiment of this invention
  • the normally known fluorine-type polymer electrolyte can be illustrated.
  • a fluorine-based polymer electrolyte in which hydrogen atoms in the above-described hydrocarbon-based polymer electrolyte are substituted with fluorine atoms can be used.
  • a perfluoroalkyl sulfonic acid polymer or a perfluorocarboxylic acid polymer can be mentioned.
  • fluorine polymer electrolytes such as Nafion (registered trademark of DuPont), Aciplex (Asahi Kasei registered trademark) manufactured by Asahi Kasei, Flemion (Asahi Glass registered trademark) manufactured by Asahi Glass, and the above-mentioned JP-A No. 2003-113136.
  • the described fluorine-based polymer electrolytes can also be used.
  • the “fluorine polymer electrolyte” means a polymer electrolyte having a fluorine atom content of more than 15% by mass in terms of a mass content ratio of elements constituting the polymer electrolyte.
  • the metal fine particles 13A included in the polymer electrolyte membrane 12 according to an embodiment of the present invention will be described.
  • the metal fine particles 13A have a function of deactivating peroxides generated during battery operation or radicals generated from the peroxides, and have a concentration gradient in the film thickness direction in the polymer electrolyte membrane 12. Are distributed.
  • “having a concentration gradient in the film thickness direction” means that the metal fine particles 13A are not uniformly dispersed in the polymer electrolyte membrane 12, but at a certain position when viewed in the film thickness direction. This indicates that the existence of the metal fine particles 13A is biased such that the concentration of the metal fine particles 13A is small and the concentration of the metal fine particles 13A is high at a certain position.
  • the metal fine particles 13A are dispersed with a concentration gradient, where the concentration of the metal fine particles 13A shows the maximum value, the effective concentration becomes higher than that of the uniform dispersion, and the radicals are effectively lost. It becomes easy to make it live.
  • the proximity effect that the activity with respect to a radical becomes high can be expected because the metal fine particles 13A are densely packed.
  • the “maximum value” means that when the function shown for the concentration change of the metal fine particles in the film thickness direction in the polymer electrolyte membrane changes from increase to decrease at a position in the film thickness direction, It is the value at.
  • the concentration of the metal fine particles 13 ⁇ / b> A may have a maximum value inside the membrane rather than the membrane surface of the polymer electrolyte membrane 12. Further, it is preferable that the maximum value of the concentration of the metal fine particles 13A is on the cathode catalyst layer side with respect to the center in the film thickness direction of the polymer electrolyte membrane. For example, the maximum value is preferably in the vicinity of the surface in contact with the cathode catalyst layer in the polymer electrolyte membrane.
  • Such a material for forming the metal fine particles 13A includes one or more metals selected from the group consisting of noble metals and noble metal alloys.
  • the forming material preferably contains at least one kind of noble metal or noble metal alloy selected from the group of noble metals consisting of platinum, gold, palladium, iridium, rhodium and ruthenium, or both, gold, palladium, ruthenium, And at least one metal selected from the noble metal group consisting of rhodium is more preferable, and palladium is particularly preferable.
  • metal fine particle 13A it is good also considering 2 or more types of metals chosen from the said group as a forming material.
  • the metal fine particles 13A may be a mixture of metal fine particles 13A made of a single metal, or may be an alloy of a plurality of types of metals.
  • the particle diameter of the metal fine particles 13A is preferably 500 nm or less. More preferably, it is 100 nm or less, More preferably, it is 50 nm or less.
  • the lower limit is not particularly limited. It may be present in the film in a metal state, and a part may be present in an ionic state. In the electron micrograph shown in FIG. 2, the metal fine particles 13 ⁇ / b> A appear as black spots, but there may be fine particles having a size that does not appear at the imaged magnification at locations where there are no black spots. .
  • the total amount of Pd metal present on and in the electrolyte membrane surface is preferably 5% or more and 95% or less with respect to the total amount of Pd metal and Pd ions present on and inside the electrolyte membrane.
  • they are 5% or more and 80% or less, More preferably, they are 5% or more and 65% or less, More preferably, they are 5% or more and 50% or less.
  • the base material 12X of the polymer electrolyte membrane 12 is manufactured using the polymer electrolyte as described above.
  • a method for producing the polymer electrolyte membrane various generally known methods can be adopted, but in the present embodiment, the following description will be made assuming that the following cast film forming method is adopted.
  • the base material 12X that can be used in the membrane electrode assembly according to an embodiment of the present invention is preferably manufactured by a cast film forming method including the following steps (i) to (iv).
  • a step of preparing a polymer electrolyte solution by dissolving the polymer electrolyte as described above in an organic solvent capable of dissolving the polymer electrolyte (Ii) The polymer electrolyte solution obtained in (i) above is cast-coated on a support substrate having a relatively smooth surface, and a polymer electrolyte cast film is formed on the support substrate.
  • a polymer electrolyte solution is prepared.
  • an organic solvent capable of dissolving the polymer electrolyte to be used is selected.
  • an organic solvent capable of dissolving these other components is preferable.
  • the organic solvent is a solvent that can dissolve the polymer electrolyte to be used, and specifically means an organic solvent that can dissolve the polymer electrolyte at a concentration of 1% by weight or more at 25 ° C.
  • an organic solvent capable of dissolving the polymer electrolyte at a concentration of 5 to 50% by weight is used.
  • the organic solvent needs to be volatile enough to be removed by heat treatment after forming a cast film of a polymer electrolyte on the support base material in the next step (ii).
  • the polymer electrolyte membrane is formed by removing the organic solvent from the cast film in the step (iii) described later.
  • the formed polymer electrolyte membrane may have uneven appearance. This is because in an organic solvent having a boiling point of 150 ° C. or lower, the organic solvent suddenly volatilizes from the cast film. Therefore, the organic solvent preferably contains at least one organic solvent having a boiling point of 150 ° C. or higher at 101.3 kPa (1 atm).
  • organic solvents suitable for the preparation of the polymer electrolyte solution include dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), and ⁇ -butyrolactone (GBL).
  • DMF dimethylformamide
  • DMAc dimethylacetamide
  • NMP N-methyl-2-pyrrolidone
  • DMSO dimethyl sulfoxide
  • GBL ⁇ -butyrolactone
  • Aprotic polar solvents such as; or chlorinated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene; alcohols such as methanol, ethanol and propanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; An alkylene glycol monoalkyl ether such as propylene glycol monomethyl ether or propylene glycol monoethyl ether is preferably used.
  • chlorinated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene
  • alcohols such as methanol, ethanol and propanol
  • ethylene glycol monomethyl ether ethylene glycol monoethyl ether
  • An alkylene glycol monoalkyl ether such as propylene glycol monomethyl ether or propylene glycol monoethyl ether is preferably used.
  • an organic solvent containing an aprotic polar solvent is preferable, and an organic solvent substantially consisting of an aprotic polar solvent is particularly preferable.
  • an organic solvent substantially composed of an aprotic polar solvent means an organic solvent mainly composed of a protic polar solvent, but does not exclude the presence of unintentionally contained water or the like. .
  • the aprotic polar solvent has an advantage that the affinity for the supporting substrate is relatively small and the aprotic polar solvent is hardly absorbed by the supporting substrate.
  • the block copolymer which is the preferred polymer electrolyte described above
  • aprotic polar solvents DMSO, DMF, DMAc, NMP, GBL or two or more selected from these are used.
  • the mixed solvent is preferable.
  • FIG. 3A is an explanatory diagram showing step (ii).
  • This step is a step of casting the polymer electrolyte solution 12S obtained in the step (i) on the support substrate P to form a casting film 12A.
  • the casting coating method various means such as a roller coating method, a spray coating method, a curtain coating method, a slot coating method, or a screen printing method can be used.
  • the polymer electrolyte solution 12S is discharged from the die 100 to form the casting film 12A.
  • the casting film 12A formed on the support substrate P has a film shape because a part of the organic solvent in the polymer electrolyte solution 12S is volatilized at the time of coating.
  • the thickness of the casting film 12A is preferably 3 ⁇ m to 50 ⁇ m.
  • the polymer electrolyte concentration of the polymer electrolyte solution 12S to be used, the coating amount of the coating apparatus, and the like may be appropriately adjusted.
  • the said support base material P is a base material which drive
  • support base material P used at a process (ii) it has sufficient endurance to polymer electrolyte solution 12S used for cast coating, and also with respect to processing conditions in process (iii) mentioned below.
  • a substrate made of a durable material is selected.
  • “durability” means that the support substrate P itself is not substantially dissolved by the polymer electrolyte solution 12S, and that the support substrate P itself swells and contracts due to the processing conditions of step (iii). This means that it does not occur and has good dimensional stability.
  • Examples of such a supporting substrate P include glass plates; metal foils such as SUS foil and copper foil; plastic films such as polyethylene terephthalate (PET) films and polyethylene naphthalate (PEN) films. Further, this plastic film may be subjected to surface treatment such as UV treatment, mold release treatment, embossing treatment, etc. on the film surface within a range that does not significantly impair the durability as described above. In the following description, it is assumed that the support substrate P is a plastic film.
  • FIG. 3B is an explanatory diagram showing step (iii).
  • This step is a step of removing the organic solvent S contained in the casting film 12A formed on the support substrate P in the step (ii) and forming the base material 12X on the support substrate P.
  • drying or washing with a washing solvent is recommended.
  • FIG. 3B illustrates that the organic solvent S is dried and removed by evaporation. It is even more preferable to remove the organic solvent by combining such drying and washing.
  • drying and washing first, drying is performed, and the film formed on the support substrate P It is particularly preferable to carry out washing with a washing solvent after most of the organic solvent S contained in is removed.
  • the drying and washing which are suitable methods as the step (iii), are performed in this order.
  • treatment such as heating, decompression, and ventilation can be employed.
  • the heat treatment is preferable in that it is good and the operation is easy.
  • the support base P hereinafter referred to as “first laminated film” in some cases
  • first laminated film on which the casting film 12A is formed is heat-treated by direct heating, hot air treatment or the like.
  • Hot air treatment is particularly preferable in that the polymer electrolyte in the casting membrane 12A is not significantly impaired.
  • the first laminated film may be passed through a drying furnace.
  • the drying furnace is configured to apply hot air whose temperature is set in a range of 40 ° C. to 150 ° C., preferably in a range of 50 ° C. to 140 ° C., in a direction perpendicular to the passing direction of the first laminated film and / or in a facing direction. Blow along.
  • the second laminated film in which the volatile component such as the organic solvent S is dried (evaporated) from the casting film 12A on the support base P and the base material 12X is formed on the support base P.
  • the base material 12X of the second laminated film thus obtained still contains a slight amount of organic solvent, this organic solvent is washed with a washing solvent. By cleaning with a cleaning solvent, it is easy to obtain the base material 12X having excellent appearance and the like.
  • a mixed solvent consisting of DMSO, DMF, DMAc, NMP, GBL, or a combination thereof, which is a suitable organic solvent in the preparation of the polymer electrolyte solution
  • pure water particularly ultrapure water, is used as the cleaning solvent. It is preferable to do.
  • the second laminated film formed continuously through the drying furnace is filled with, for example, a cleaning solvent. It can wash
  • FIG. 3C is an explanatory diagram showing step (iv).
  • the base material 12X of the polymer electrolyte membrane 12 is obtained by removing the supporting substrate P from the second laminated film formed in step (iii) by peeling or the like. Since the obtained base material 12X is obtained by a suitable cast film forming method, it is substantially non-porous.
  • substantially non-porous means that minute through holes such as voids are not formed in the polymer electrolyte membrane 12.
  • the polymer electrolyte membrane 12 may be a membrane having such a void as long as it is a small amount of voids or a small diameter void that does not hinder the operation of the fuel cell.
  • the case where the support substrate P is continuously running has been described, but of course, using the single wafer support substrate P Also, the polymer electrolyte membrane 12 can be obtained.
  • the polymer electrolyte solution coated on the single-wafer supporting substrate P can be removed from the organic solvent by storing it in an appropriate drying furnace, and thus obtained.
  • the second laminated film as a single wafer can be cleaned by immersing it in a cleaning tank equipped with a cleaning solvent.
  • the second laminated film may be removed by removing the cleaning solvent remaining or adhering after the support substrate P is removed, or the second laminated film after washing may be heated as it is. Then, after the remaining or attached cleaning solvent is removed by drying, the supporting substrate P may be removed.
  • the polymer electrolyte membrane 12 and the membrane electrode assembly 20 are manufactured using the base material 12X.
  • the metal layer 13 is formed on one surface of the base material 12X.
  • the metal layer 13 can be formed by physically depositing the metal fine particle forming material on the surface of the base material 12X.
  • physical vapor deposition generally known methods such as vapor deposition, sputtering, and ion plating can be used.
  • the ion plating method is preferable.
  • the palladium particles SP are illustrated as being stacked by an ion plating method using palladium as a target metal.
  • the metal layer 13 having a film-like form is adopted, but it may not be a film-like form.
  • the “metal layer” includes the metal fine particle layer in addition to the layer having a film form.
  • the metal fine particle layer can be formed by applying and solidifying a dispersion obtained by mixing fine particles of the above-described forming material and a resin precursor or a resin solution onto the surface of the base material 12X. Fine particles having an average particle diameter of several nm to several tens of nm can be used, and the fine particles may be aggregated during coating. Moreover, as a precursor, the precursor of a photocurable resin or a thermosetting resin can be used. As the coating method, known techniques such as a spray method and a die coating method can be used.
  • the metal layer formed by these coating methods has a structure in which metal fine particles are finely dispersed on the electrolyte membrane surface.
  • a metal fine particle layer unlike the film-like metal layer formed by the physical vapor deposition described above, a gap is formed between the metal fine particles, and therefore the polymer electrolyte membrane and the catalyst layer are interposed through the gap. The exchange of ions between them is easy. Therefore, such a metal fine particle layer can maintain power generation performance.
  • the solvent of the dispersion is selected based on the solubility of the polymer electrolyte forming the base material 12X.
  • the dispersion is a poor solvent for the polymer electrolyte constituting the base material 12X.
  • the solvent is a mixed solvent
  • at least one kind of solvent that is a poor solvent is used for the polymer electrolyte that forms the base material 12X, and the physical properties are adjusted so as to be a poor solvent.
  • the poor solvent for the polymer electrolyte refers to a solvent that cannot dissolve the polymer electrolyte at a concentration of 0.1% by mass or more at 25 ° C.
  • a good solvent for a polymer electrolyte refers to a solvent that can dissolve the polymer electrolyte at a concentration of 0.1% by mass or more at 25 ° C. Specifically, by dissolving a predetermined amount of polymer electrolyte in a predetermined amount of 25 ° C. solvent to prepare a solution, drying the solution and measuring the dry mass, the polymer electrolyte with respect to the solvent Measure the solubility of.
  • the solvent of the dispersion can be appropriately selected by measuring the solubility according to the type of polymer electrolyte and deterioration inhibitor used.
  • the above-described forming material is used as a target, and the energy of ionized gas that collides with the target is controlled, thereby controlling the particle diameter of the sputtered particles.
  • a metal fine particle layer in which particles are spread in layers can be formed.
  • the metal layer formed by the physical vapor deposition method has excellent adhesion to the electrolyte membrane surface, and can suppress the decrease in the transport amount of hydrogen ions at the interface between the electrolyte membrane and the catalyst layer. Can be maintained.
  • the base material 12X on which the metal layer 13 is formed is sandwiched between the electrodes 50 and 51, and forced energization is performed in the same direction as energization during power generation from the external power source 52.
  • the metal layer 13 is ionized and disappears, and the ionized metal penetrates into the base material 12X.
  • the metal ions dissolved from the metal layer 13 precipitate as metal fine particles 13A while the metals aggregate together in the base material 12X.
  • the metal layer 13 is formed using two or more kinds of forming materials, it may be precipitated as an alloy.
  • FIG. 4C schematically shows a state in which a large amount of the metal fine particles 13A are deposited in the width W, and the concentration is higher than that of other portions. Further, it is shown that the high concentration portion is on the side where the original metal layer 13 was present (above the base material 12X) rather than the center in the thickness direction of the base material 12X.
  • the polymer electrolyte membrane 12 which is one embodiment of this invention is manufactured.
  • platinum or a platinum-based alloy supported on carbon is mixed with a solvent of a perfluoroalkylsulfonic acid resin to form a paste (hereinafter sometimes referred to as catalyst ink 14S).
  • the anode catalyst layer 14a is obtained by applying and drying one surface of the polymer electrolyte membrane 12.
  • the cathode catalyst layer 14b is formed by applying and drying the catalyst ink 14S on the other surface of the polymer electrolyte membrane 12, and the membrane electrode assembly 20 which is one embodiment of the present invention is manufactured.
  • a metal fine particle dispersion in which metal fine particles are added and dispersed in the polymer electrolyte solution is prepared, and these solutions are prepared. And a method of forming using the dispersion.
  • the casting membrane 12A is formed on the support substrate P by discharging the polymer electrolyte solution 12S from the die 100. This step is the same as that in FIG. 3A described above.
  • a casting film 19A is formed on the casting film 12A by discharging a metal fine particle dispersion 19S containing separately prepared metallic fine particles 13A.
  • the metal fine particle dispersion 19S is discharged onto the casting film 12A, the surface of the casting film 12A is swollen by the solvent contained in the metal fine particle dispersion 19S, and the interface between the casting film 12A and the casting film 19A is unclear. become.
  • the metal fine particles 13A in the metal fine particle dispersion 19S are difficult to be dispersed in the casting film 12A obtained by evaporating a part of the solvent in advance, the metal fine particles 13A are localized in the casting film 19A. Cheap.
  • the organic solvent S contained in the casting membrane 12A and the casting membrane 19A is removed, and the polymer electrolyte membrane 12 is formed on the support substrate P.
  • the interface between the casting film 12A and the casting film 19A becomes unclear and is formed as an integral polymer electrolyte membrane 12.
  • the casting film 12A or the casting film 19A can be further laminated on the casting film 19A formed in FIG. 5B.
  • the order of stacking the manufacturing steps described above may be reversed. That is, first, the casting film 19A is formed on the support substrate P, and then the casting film 12A is laminated on the casting film 19A to remove the solvent, thereby forming the polymer electrolyte membrane 12. Good.
  • the polymer electrolyte membrane 12 and the membrane electrode assembly 20 may be manufactured using a method as shown in FIGS. 6A to 6C.
  • an anode catalyst layer 14a laminated and integrated with the gas diffusion layer 16a is obtained by applying and drying the catalyst ink 14S on the surface of the gas diffusion layer 16a.
  • a cathode catalyst layer laminated and integrated with the gas diffusion layer is also formed.
  • the base material 12X on which the metal layer 13 is formed is sandwiched and joined between the obtained anode catalyst layer 14a and cathode catalyst layer 14b by the same method as in FIG. 4A described above.
  • a known method for example, a method described in J. Electrochem. Soc .: Electrochemical Science Science Technology, 1988, 135 (9), 2209
  • a membrane electrode assembly for a fuel cell can be obtained by applying the catalyst ink 14S to the polymer electrolyte membrane 12 and drying it to form a catalyst layer directly on the surface of the membrane.
  • separators 18a and 18b are provided outside the gas diffusion layers 16a and 16b to form a fuel cell, and then hydrogen is supplied to the anode catalyst layer 14a and oxygen is supplied to the cathode catalyst layer 14b. Power is supplied to generate power, and initial acclimation operation is performed until the battery voltage called aging is saturated. Usually, after assembly of the fuel cell, aging is performed because power generation tends to become unstable because the proton conduction path is not sufficiently formed. Here, by energizing in this aging, the metal layer 13 is ionized and deposited as metal fine particles 13A in the base material 12X.
  • the polymer electrolyte membrane 12 and the membrane electrode assembly 20 which are one embodiment of the present invention can be produced as described above.
  • the membrane electrode assembly having the above-described configuration, it is possible to obtain a membrane electrode assembly with high durability by achieving long-term stability of the polymer electrolyte.
  • radicals in the polymer electrolyte membrane can be effectively deactivated, and long-term stabilization can be achieved.
  • the metal layer 13 is formed on one surface of the base material 12X.
  • the metal layer 13 may be formed on either one of the surfaces.
  • a polymer film obtained by forming a polymer to be measured by a cast film forming method was obtained, and the obtained polymer film was cut to an appropriate weight.
  • the dry weight of the cut polymer film was measured using a halogen moisture meter set at a heating temperature of 110 ° C.
  • the polymer membrane thus dried was immersed in 5 mL of a 0.1 mol / L sodium hydroxide aqueous solution, and further 50 mL of ion exchange water was added and left for 2 hours.
  • titration was performed by gradually adding 0.1 mol / L hydrochloric acid to the solution in which the polymer film was immersed, and the neutralization point was determined.
  • the ion exchange capacity (unit: meq / g) of the polymer was calculated from the dry weight of the cut polymer film and the amount of hydrochloric acid required for neutralization.
  • Example 1 [Synthesis of Polymer Electrolyte 1] 2,2.4 g of 2,2-dimethylpropanol was dissolved in 72.5 g of pyridine. To this, 50 g of 2,5-dichlorobenzenesulfonic acid chloride was added at 0 ° C., and the mixture was stirred at room temperature for 1 hour to be reacted. To the reaction mixture, 300 mL of toluene and 250 mL of 2 mol% hydrochloric acid were added, stirred for 30 minutes, and allowed to stand to separate the organic layer.
  • the separated organic layer was washed sequentially with 150 mL of water, 150 mL of 10 wt% aqueous potassium carbonate solution and 150 mL of water, and then the solvent was distilled off under reduced pressure to obtain 105 g of a concentrated solution.
  • the concentrate was cooled to 0 ° C., and the precipitated solid was separated by filtration.
  • the separated solid was dried to obtain 49.3 g (yield: 81.4%) of a white solid of 2,5-dichlorobenzenesulfonic acid (2,2-dimethylpropyl).
  • the obtained polymerization solution was poured into 1200 g of hot water at 70 ° C., and the resulting precipitate was collected by filtration. Water was added to the precipitate so that the total amount of the precipitate and water was 696 g, and further 9.2 g of a 35 wt% sodium nitrite aqueous solution was added. To this slurry solution, 160 g of 69% by weight nitric acid was added dropwise, and then stirred at room temperature for 1 hour.
  • the slurry solution was filtered and the collected crude polymer was washed with water until the pH of the filtrate exceeded 1.
  • water is added to a flask equipped with a condenser until the total weight of the crude polymer and the crude polymer and water reaches 698 g, and a 5% by weight lithium hydroxide aqueous solution is added to the slurry solution of the crude polymer and water.
  • a 5% by weight lithium hydroxide aqueous solution is added to the slurry solution of the crude polymer and water.
  • the crude polymer was collected by filtration, washed by immersion using 200 g of water and then 250 g of methanol, and dried to obtain the following formula (2).
  • the target polymer electrolyte 1 containing the segment shown by these was obtained.
  • the yield was 14.7g.
  • 1 H-NMR spectrum was measured, and it was confirmed that the 2,2-dimethylpropoxysulfonyl group was quantitatively converted to a sulfo group.
  • Mw 455000
  • Mn 195000
  • IEC ion exchange capacity
  • polymer electrolyte membrane 1A Preparation of polymer electrolyte membrane 1A
  • the polymer electrolyte 1 obtained as described above was dissolved in N, N-dimethyl sulfoxide to prepare a polymer electrolyte solution having a concentration of 10% by weight.
  • the obtained polymer electrolyte solution was continuously cast and applied to a polyethylene terephthalate (PET) film (Toyobo Co., Ltd., E5000 grade, thickness 100 ⁇ m) having a width of 300 mm as a supporting substrate using a slot die.
  • PET polyethylene terephthalate
  • Toyobo Co., Ltd., E5000 grade, thickness 100 ⁇ m having a width of 300 mm as a supporting substrate using a slot die.
  • a cast film was formed.
  • the support substrate and the cast film were continuously conveyed to a hot air heater drying furnace, and the solvent was removed to form a film.
  • the obtained membrane was immersed in 2N sulfuric acid for 2 hours, then washed with ion-exchanged water, further air-dried, and then peeled off from the supporting base material to produce a polymer electrolyte membrane 1A.
  • the film thickness of the polymer electrolyte membrane 1A was 20 ⁇ m.
  • the amount of laminated Pd was measured using the following inductively coupled plasma optical emission spectrometer (ICP emission). As a result of the measurement, the amount of Pd laminated as the Pd layer was 0.18% (1800 ppm) with respect to the weight of the polymer electrolyte membrane.
  • ICP luminescence measuring device SII Nanotechnology, SPS3000 Measurement wavelength: 340.46 nm
  • the catalyst ink was applied to a 3 cm ⁇ 3 cm region in the center of the surface not having the Pd layer by a spray method. At this time, the distance from the discharge port to the film was set to 6 cm, and the stage temperature was set to 75 ° C. After overcoating in the same manner, the solvent was removed to form an anode catalyst layer. As an anode catalyst layer, 14.2 mg of solid content (platinum weight: 0.6 mg / cm 2 ) was applied. Subsequently, a catalyst ink was similarly applied on the Pd layer to form a cathode catalyst layer, thereby obtaining a membrane electrode assembly 1B. As the cathode catalyst layer, 14.2 mg of solid content (platinum weight: 0.6 mg / cm 2 ) was applied.
  • a carbon cloth as a gas diffusion layer and a carbon separator in which a gas passage groove is cut are disposed on both outer sides of the membrane electrode assembly 1B obtained as described above, and a current collector is further disposed on the outer side thereof.
  • a fuel cell having an effective electrode area of 9 cm 2 was assembled by sequentially arranging the end plates and fastening them with bolts.
  • a known material can be used as the conductive material as the current collector used in the present invention, but the porous carbon woven fabric, carbon non-woven fabric or carbon paper efficiently transports the source gas to the catalyst. Therefore, it is preferable.
  • FIG. 7 to 9 are TEM observation images obtained, FIG. 7 is near the interface between the anode catalyst layer and the polymer electrolyte membrane, FIG. 8 is near the center of the polymer electrolyte membrane, and FIG. 9 is the cathode. It is a TEM photograph which shows the mode of the interface vicinity of a catalyst layer and a polymer electrolyte membrane. In addition, the TEM observation magnification of FIG. 9 is 10,000 times, and the TEM observation magnification of FIGS. 7 and 8 is 50,000 times.
  • the particle diameter of the Pd particles precipitated in the film was confirmed visually from a TEM observation image.
  • Pd particles near the interface between the cathode catalyst layer and the polymer electrolyte membrane were about 10 nm to about 50 nm.
  • the Pd particle size in the vicinity of the interface between the anode catalyst layer and the polymer electrolyte membrane and in the vicinity of the center of the polymer electrolyte membrane was about 10 nm or less.
  • ICP emission inductively coupled plasma emission spectrometer
  • the treated solution was made up to a volume of 5 mL, and the solution was measured using an inductively coupled plasma emission spectrometer (ICP emission).
  • ICP luminescence measuring device SII Nanotechnology, SPS3000 Measurement wavelength: 340.46 nm
  • the anode / cathode catalyst layer and the anode catalyst layer are removed by removing the membrane electrode assembly from the fuel cell that has been subjected to durability evaluation, and placing it in a mixed solution of ethanol / water (ethanol content: 90% by mass) and subjecting it to ultrasonic treatment. Removed. Next, 4 mg of the polymer electrolyte membrane before and after the test was immersed in 10 ⁇ L of a 25 mass% tetramethylammonium hydroxide methanol solution and reacted at 100 ° C. for 2 hours. After standing to cool, the weight average molecular weight of the obtained reaction solution was measured using gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • the concentrated residue was purified by silica gel chromatography (developing solvent: chloroform). From the obtained eluate, the solvent was distilled off under reduced pressure. The residue was dissolved in 500 mL of toluene at 70 ° C., and then cooled to room temperature. The precipitated solid was separated by filtration, and the separated solid was dried to obtain 31.2 g of a white solid of 4,4′-dichlorobiphenyl-2,2′-disulfonic acid di (2,2-dimethylpropyl). It was.
  • the bath temperature was raised to 160 ° C., and the mixture was kept warm for 14 hours.
  • the reaction solution was added to a mixed solution of 1000 g of methanol and 200 g of 35 wt% hydrochloric acid, and the deposited precipitate was filtered, washed with ion-exchanged water until neutral, and dried. 27.2 g of the obtained crude product was dissolved in 97 g of N, N-dimethylacetamide, insoluble matters were filtered, and then added to a mixed solution of 1100 g of methanol and 100 g of 35 wt% hydrochloric acid.
  • the obtained polymerization solution was put into 3360 g of 13 wt% hydrochloric acid and stirred at room temperature for 30 minutes.
  • the resulting precipitate was filtered, 3360 g of 13 wt% hydrochloric acid was added, and the mixture was stirred at room temperature for 30 minutes. Thereafter, the precipitate was filtered and washed with ion exchange water until the pH of the filtrate exceeded 4.
  • 840 g of ion exchanged water and 790 g of methanol were added, and the mixture was heated and stirred at a bath temperature of 90 ° C. for 1 hour.
  • the target polymer electrolyte 2 containing the segment shown by these was obtained.
  • the yield was 17.25g. Mw: 5.78 ⁇ 10 5
  • polymer electrolyte membrane 2A The polymer electrolyte 2 obtained as described above was dissolved in N-methyl 2-pyrrolidone to prepare a polymer electrolyte solution having a concentration of 7.5% by weight. The obtained polymer electrolyte solution was continuously cast and applied to a polyethylene terephthalate (PET) film (Toyobo Co., Ltd., E5000 grade, thickness 100 ⁇ m) having a width of 300 mm as a supporting substrate using a slot die. Thus, a cast film was formed. Thereafter, the support substrate and the cast film were continuously conveyed to a hot air heater drying furnace, and the solvent was removed to form a film.
  • PET polyethylene terephthalate
  • the obtained membrane was immersed in 2N sulfuric acid for 2 hours, then washed with ion-exchanged water, further air-dried, and then peeled off from the support base material to produce a polymer electrolyte membrane 2A.
  • the film thickness of the polymer electrolyte membrane 2A was 10 ⁇ m.
  • a catalyst layer (anode catalyst layer, cathode catalyst layer) is formed on both surfaces to form a membrane electrode assembly 2B.
  • Example 2B Further, a fuel cell was assembled and durability was evaluated in the same manner as in Example 1 except that the membrane electrode assembly 2B was used. In the durability evaluation, the fuel cell was continuously operated for 500 hours. Thereafter, the membrane electrode assembly was taken out from the fuel cell, and the weight average molecular weight of the polymer electrolyte membrane 2A was measured.
  • Example 3 [Synthesis of polymer electrolyte 3] Under an argon atmosphere, 7.69 g (35.2 mmol) of anhydrous nickel bromide, 5.49 g (35.2 mmol) of 2,2′-bipyridyl and 460 g of N-methylpyrrolidone were added to the flask. A containing solution was prepared. In a separate flask, 17.2 g (263.8 mmol) of zinc powder and 4,4′-dichlorobiphenyl-2,2′-disulfonic acid di (2) synthesized by the method described in Example 1 of JP-A-2007-270118 were used.
  • the block copolymer which has a segment which does not have an ion exchange group substantially, and was shown as the polymer electrolyte 3.
  • Mn 1.73 ⁇ 10 5
  • Mw 3.46 ⁇ 10 5
  • polymer electrolyte membrane 3A Preparation of polymer electrolyte membrane 3A
  • the polymer electrolyte 3 was dissolved in N, N-dimethyl sulfoxide to prepare a polymer electrolyte solution having a concentration of 10% by weight.
  • a polymer electrolyte membrane 3A was produced in the same manner as in Example 1 except that this polymer electrolyte solution was used.
  • the thickness of the polymer electrolyte membrane 3A was 20 ⁇ m.
  • a carbon cloth, a carbon separator, a current collector and an end plate are arranged in this order on both outer sides of the membrane electrode assembly 3B obtained as described above in the same manner as in Example 1, and these are tightened with bolts.
  • a fuel cell having an effective electrode area of 25 cm 2 was assembled.
  • the membrane / electrode assembly was taken out of the fuel cell after the OCV test, and the molecular weight of the polymer electrolyte membrane after durability evaluation was measured in the same manner as in Example 1.
  • Example 1 and Comparative Example 1 the weight average molecular weight maintenance rates from the initial state of the polymer electrolyte 1 are summarized in Table 4 below.
  • Example 2 and Comparative Example 2 the weight average molecular weight maintenance rates from the initial state of the polymer electrolyte 2 are shown together in Table 5 below.
  • Example 3 and Comparative Example 3 the weight average molecular weight maintenance ratio from the initial state of the polymer electrolyte 3 is shown together in Table 6 below.
  • the evaluation results indicate that the higher the molecular weight maintenance rate before and after the load fluctuation test, the less the deterioration of the polymer electrolyte membrane and the better the long-term stability.
  • the ratio of “the amount of Pd ions present in the film after durability evaluation” to “the total amount of Pd present in the film after durability evaluation” Table 7 summarizes the ratio of “the amount of Pd metal present in the film after durability evaluation” to “the total amount of Pd present in the film after durability evaluation”.
  • Pd metal indicates that Pd is not ionized and is dispersed as fine particles in the polymer electrolyte membrane.
  • the membrane / electrode assembly of the present invention was less deteriorated and stable than the membrane / electrode assembly of the comparative example in continuous power generation (that is, continuous oxidation-reduction reaction). .
  • the durability evaluation it was confirmed that Pd formed as a Pd layer on the surface of the polymer electrolyte membrane was present in the polymer electrolyte membrane in an ion or metal state. It was. Further, no Pd layer remained on the surface of the polymer electrolyte membrane. This confirmed the usefulness of the present invention.
  • the membrane / electrode assembly including the polymer electrolyte membrane is excellent in long-term stability and is suitably used for a fuel cell.

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Abstract

La présente invention concerne une membrane électrolytique polymère comprenant : un matériau de base de type membrane composé d'un électrolyte polymère ; et des particules fines de métal dispersées dans le matériau de base. Le matériau formant les particules fines de métal contient au moins un métal choisi dans le groupe constitué par les métaux nobles et les alliages de métaux nobles, et les particules fines de métal sont dispersées de manière à présenter un gradient de concentration dans le sens de l'épaisseur du matériau de base.
PCT/JP2012/050851 2011-01-17 2012-01-17 Membrane électrolytique polymère, ensemble électrode à membrane et pile à combustible WO2012099118A1 (fr)

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WO2024004857A1 (fr) * 2022-06-27 2024-01-04 東レ株式会社 Membrane électrolytique, membrane électrolytique avec couche de catalyseur, feuille de transfert utilisée pour sa production, ensemble membrane-électrode, dispositif d'électrolyse de l'eau et procédé de fabrication de membrane électrolytique avec couche de catalyseur

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JPH06103992A (ja) * 1992-09-22 1994-04-15 Tanaka Kikinzoku Kogyo Kk 高分子固体電解質型燃料電池
JP2003059511A (ja) * 2001-08-17 2003-02-28 Matsushita Electric Ind Co Ltd 燃料電池用電解質膜−電極接合体、その製造方法、および高分子電解質型燃料電池
JP2003086201A (ja) * 2001-09-11 2003-03-20 Toyota Motor Corp 燃料電池用電解質膜
JP2006302578A (ja) * 2005-04-18 2006-11-02 Nissan Motor Co Ltd 燃料電池の運転方法及び燃料電池システム
JP2007123122A (ja) * 2005-10-28 2007-05-17 Nissan Motor Co Ltd 燃料電池用電解質膜および膜電極接合体
JP2009097003A (ja) * 2007-09-25 2009-05-07 Sumitomo Chemical Co Ltd 高分子電解質組成物及び燃料電池
JP2009187866A (ja) * 2008-02-08 2009-08-20 Toyota Motor Corp 膜・電極接合体

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JPH06103992A (ja) * 1992-09-22 1994-04-15 Tanaka Kikinzoku Kogyo Kk 高分子固体電解質型燃料電池
JP2003059511A (ja) * 2001-08-17 2003-02-28 Matsushita Electric Ind Co Ltd 燃料電池用電解質膜−電極接合体、その製造方法、および高分子電解質型燃料電池
JP2003086201A (ja) * 2001-09-11 2003-03-20 Toyota Motor Corp 燃料電池用電解質膜
JP2006302578A (ja) * 2005-04-18 2006-11-02 Nissan Motor Co Ltd 燃料電池の運転方法及び燃料電池システム
JP2007123122A (ja) * 2005-10-28 2007-05-17 Nissan Motor Co Ltd 燃料電池用電解質膜および膜電極接合体
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