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WO2010047329A1 - Électrolyte composite organique-inorganique, membrane d'électrolyte, ensemble électrode-membrane et pile à combustible - Google Patents

Électrolyte composite organique-inorganique, membrane d'électrolyte, ensemble électrode-membrane et pile à combustible Download PDF

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Publication number
WO2010047329A1
WO2010047329A1 PCT/JP2009/068065 JP2009068065W WO2010047329A1 WO 2010047329 A1 WO2010047329 A1 WO 2010047329A1 JP 2009068065 W JP2009068065 W JP 2009068065W WO 2010047329 A1 WO2010047329 A1 WO 2010047329A1
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Prior art keywords
metal phosphate
electrolyte
polymer
group
membrane
Prior art date
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PCT/JP2009/068065
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English (en)
Japanese (ja)
Inventor
武史 仲野
友裕 小野
望 須郷
敬次 久保
高士 日比野
弼源 許
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Nagoya University NUC
Kuraray Co Ltd
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Nagoya University NUC
Kuraray Co Ltd
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Priority to JP2010534815A priority Critical patent/JP5555636B2/ja
Publication of WO2010047329A1 publication Critical patent/WO2010047329A1/fr
Anticipated expiration legal-status Critical
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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
    • 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
    • H01M8/1023—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
    • 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
    • H01M8/1048—Ion-conducting additives, e.g. ion-conducting particles, heteropolyacids, metal phosphate or polybenzimidazole with phosphoric acid
    • 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
    • H01M8/1009—Fuel cells with solid electrolytes with one of the reactants being liquid, solid or liquid-charged
    • H01M8/1011—Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
    • 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

  • An electrolyte suitable for producing an electrolyte membrane that has excellent methanol barrier properties, high output, and excellent flexibility and moldability in a direct methanol fuel cell (DMFC) as a fuel.
  • the present invention relates to an electrolyte membrane composed of the electrolyte, a membrane-electrode assembly using the electrolyte membrane, and a solid polymer fuel cell.
  • the present invention is an electrolyte suitable for producing an electrolyte membrane for use in a polymer electrolyte fuel cell, and realizes low resistance and high output even under high temperature and low humidity conditions.
  • Electrolyte suitable for producing an electrolyte membrane excellent in flexibility and moldability electrolyte membrane comprising the electrolyte, membrane-electrode assembly and solid polymer fuel cell using the electrolyte membrane about.
  • PEFC polymer electrolyte fuel cell
  • a polymer electrolyte fuel cell is generally configured as follows. First, catalyst layers containing carbon powder carrying a white metal catalyst and an ion conductive binder made of a polymer electrolyte are formed on both sides of the polymer electrolyte membrane having ion conductivity. A gas diffusion layer, which is a porous material through which fuel gas and oxidant gas are passed, is formed outside each catalyst layer. Carbon paper, carbon cloth, or the like is used as the gas diffusion layer. A structure in which a catalyst layer and a gas diffusion layer are integrated is called a gas diffusion electrode.
  • a structure in which a pair of gas diffusion electrodes is bonded to an electrolyte membrane so that the catalyst layer faces the electrolyte membrane is a membrane-electrode assembly ( It is called MEA (Mebrane Electrode Assembly).
  • MEA Membrne Electrode Assembly
  • separators having conductivity and airtightness are disposed on both sides of the membrane-electrode assembly.
  • a gas flow path for supplying fuel gas or oxidant gas (for example, air) to the electrode surface is formed in the contact portion of the membrane-electrode assembly and the separator or in the separator. Electric power is generated by supplying a fuel gas such as hydrogen or methanol to one electrode (fuel electrode, anode) and an oxidant gas containing oxygen such as air to the other electrode (oxygen electrode, cathode).
  • the fuel is ionized to produce protons and electrons
  • the protons pass through the electrolyte membrane
  • the electrons travel through an external electric circuit formed by connecting both electrodes, and are sent to the oxygen electrode
  • Water is produced by the reaction.
  • the chemical energy of the fuel can be directly converted into electric energy and taken out.
  • an electrolyte membrane that can reduce methanol crossover (MCO) in which methanol permeates the electrolyte membrane during operation and power generation performance and fuel utilization efficiency are reduced is required.
  • MCO methanol crossover
  • it is indispensable to efficiently conduct proton conduction, that is, because the polymer electrolyte membrane has low cell resistance, and methanol is indispensable during DMFC power generation. It penetrates the water part contained in the water.
  • an electrolyte membrane that can exhibit high ionic conductivity even in a state where the amount of water contained as a methanol permeation path is small, that is, in a low humidity state, is desired.
  • polymer electrolyte membranes used in polymer electrolyte fuel cells can exhibit high ionic conductivity by hydrating them, and in low humidity or non-humidified conditions where the moisture content of the polymer electrolyte membrane is reduced, There is a problem that conductivity is reduced and cell resistance during power generation is increased. For this reason, in order to maintain a high output, it is necessary to humidify the fuel battery cell, and there is a problem of increasing the size of the apparatus and complication of the system.
  • the catalytic activity of the catalyst responsible for the electrochemical reaction at the anode and the cathode is known to increase as the temperature rises.
  • operation at a temperature higher than the boiling point of water is required. Therefore, an electrolyte membrane capable of exhibiting high ionic conductivity even in a low humidity state is desired for a high-performance and inexpensive fuel cell. Therefore, there is a demand for an electrolyte membrane that exhibits high ionic conductivity even under high temperature and non-humidified conditions, and thus can achieve reduction in cell resistance and improvement in output of a fuel cell.
  • Nafion registered trademark of DuPont
  • DuPont which is a perfluorocarbon sulfonic acid polymer
  • Nafion is a fluorine-based polymer
  • environmental considerations are necessary during synthesis and disposal, and it is expensive. Therefore, development of a novel electrolyte membrane is desired.
  • sulfonated polyether ether ketone which is a heat-resistant aromatic polymer (Patent Document 1)
  • PES polyethersulfone
  • Non-Patent Document 1 sulfonated aromatic polymers
  • sulfonated aromatic polymers are known to have high heat resistance, but due to their rigidity, there is a problem of poor moldability and mechanical durability.
  • sulfonated aromatic polymers require water for high-efficiency ion conduction, there is a problem that ion conductivity under low humidity conditions is insufficient.
  • metal phosphates exhibit solid ionic conductivity at a temperature below the operating temperature of zirconia while being a solid oxide.
  • metal phosphate alone has problems in mechanical durability and formability due to the rigidity and brittleness inherent in inorganic materials, so polytetrafluoroethylene (PTFE) Development of a composite film using a fluororesin represented by the above as a binder has been studied.
  • PTFE polytetrafluoroethylene
  • the metal phosphate is coated with a fluororesin that does not have ionic conductivity, so in order to express high ionic conductivity, the mass ratio of the metal phosphate Therefore, it is difficult to produce an electrolyte membrane having both ionic conductivity and membrane strength because the strength of the membrane is reduced as the mass ratio of the fluororesin as a binder is reduced.
  • Patent Document 3 an electrolyte containing a sulfonated aromatic polymer and an inorganic solid material such as a metal phosphate has been proposed (Patent Document 3).
  • a binder is not used, mechanical durability and formability are poor. Since it is sufficient, it is difficult to increase the ionic conductivity.
  • a first object of the present invention is to provide an electrolyte that exhibits low resistance (electric resistance) under low humidity conditions, reduces MCO during DMFC power generation, improves output, and has excellent flexibility and moldability. And a membrane-electrode assembly and a solid polymer fuel cell using the electrolyte membrane.
  • the second object of the present invention is to exhibit high proton conductivity even under conditions of high temperature, low humidity or no humidification, excellent membrane strength, flexibility and mechanical durability, and high formability (assembly property).
  • the third object of the present invention is to have low resistance under low humidity conditions and to improve output by reducing methanol crossover (MCO) during direct methanol fuel cell (DMFC) power generation.
  • Electrolyte that is excellent in electrolyte can reduce elution of phosphoric acid from the electrolyte, and can improve durability while maintaining power generation performance, electrolyte membrane comprising the electrolyte, and membrane-electrode using the electrolyte membrane
  • An object of the present invention is to provide a joined body and a polymer electrolyte fuel cell.
  • the inventors of the present invention provide a polymer block that is phase-separated from each other, and a block copolymer that includes a polymer block having an ion conductivity function and a flexibility function, respectively, and a metal phosphate having an ion conductivity
  • the inventors have found that an electrolyte composed of a salt-containing composition satisfies the first object, and completed the present invention.
  • the present inventors also provide polymer blocks that are phase-separated from each other, a block copolymer that includes a polymer block having an ion conductive function and a flexible function, respectively, and a metal having an ion conductive property.
  • An electrolyte comprising a phosphate-containing composition the electrolyte having a mass ratio of block copolymer / metal phosphate in a specific range has been found to satisfy the second object, and the present invention has been completed did.
  • the inventors of the present invention include polymer blocks that are phase-separated from each other, each having a polymer block having an ion conductive function and a flexible function, and a metal phosphate having ion conductivity.
  • An electrolyte comprising a composition the electrolyte having a median diameter measured by static light scattering of the metal phosphate of 10 nm to 1 ⁇ m, and thus the electrolyte membrane, has been found to satisfy the third object, and the present invention completed.
  • the present invention is broadly divided into three modes that can achieve the first, second, and third objects, respectively.
  • the first aspect of the present invention capable of achieving the first object is a block copolymer comprising polymer blocks (A) and (B) that are phase-separated from each other, wherein the polymer block (A) is: A block copolymer having an ion conductive group, the polymer block (B) forming a flexible phase, the ion conductive group being substantially present only in the polymer block (A), and a metal having ion conductivity
  • the present invention relates to an electrolyte comprising a composition containing a phosphate.
  • the mass ratio of the block copolymer / the metal phosphate is 99/1 to 30/70.
  • the second aspect of the present invention capable of achieving the second object is a block copolymer comprising polymer blocks (A) and (B) that are phase-separated from each other, wherein the polymer block (A) is: A block copolymer having an ion conductive group, the polymer block (B) forming a flexible phase, the ion conductive group being substantially present only in the polymer block (A), and a metal having ion conductivity A composition containing a phosphate, wherein the mass ratio of the block copolymer / the metal phosphate is 80/20 to 1/99.
  • the third aspect of the present invention capable of achieving the third object is a block copolymer comprising polymer blocks (A) and (B) that are phase-separated from each other, wherein the polymer block (A) is: Having an ion conductive group, the polymer block (B) forms a flexible phase, and the ion conductive group has a block copolymer substantially present only in the polymer block (A), and has an ion conductivity And an electrolyte comprising a composition containing a metal phosphate having an average particle size of 10 nm to 1 ⁇ m.
  • the mass ratio of the block copolymer / the metal phosphate is preferably 99/1 to 30/70.
  • phase separation means phase separation in a microscopic sense, and more specifically, called microphase separation in which the formed domain size is less than or equal to the wavelength of visible light (3800 to 7800 mm). Is.
  • the polymer block (A) since the polymer block (A) has an ion conductive group, an ion channel is formed by the assembly of the polymer blocks (A) and becomes a path for ions. Since the polymer block (B) functions as a flexible phase, moldability (such as assembling property, bonding property, and tightening property) is improved in manufacturing a membrane-electrode assembly and a polymer electrolyte fuel cell.
  • Ion conductive groups include sulfonic acid groups, phosphonic acid groups, and salts thereof.
  • the polymer block having an ion conductive function in the polymer electrolyte supplements the ion conduction network of the metal phosphate, sufficient ions can be obtained even when the metal phosphates are not in contact with each other. Conductivity can be developed.
  • the metal phosphate does not require water for ionic conduction, it can reduce the water content that is a path through which methanol permeates through the electrolyte membrane, and can achieve both low resistance and low MCO.
  • the electrolyte membrane made of the electrolyte of the present invention, the power generation performance can be improved from the viewpoint of moisture management. Furthermore, since the polymer block forming the flexible phase imparts flexibility to the electrolyte membrane, the moldability of the electrolyte membrane, the mechanical durability, and the bondability with the electrode, which are problematic only with metal phosphates, are improved. Can do.
  • the contact area between the metal phosphate and the block copolymer is increased, and the weight of the block copolymer is increased.
  • the ion conductive group of the combined block (A) and the phosphate group of the metal phosphate form a hydrogen bond, thereby improving the density of the electrolyte membrane.
  • the hydrogen bond formed between the ion conductive group of the block copolymer and the phosphate group of the metal phosphate improves the water resistance of the metal phosphate, thereby reducing the phosphate elution amount and protons.
  • the density of the ion conductive group in the ion channel that becomes the path increases, the proton conduction efficiency in the electrolyte membrane improves, and the MCO during DMFC power generation is further suppressed, so that the DMFC power generation output can be improved.
  • the above-described polymer electrolyte and a metal phosphate having ionic conductivity under non-humidified conditions are combined to form a high moisture-free condition under which the electrolyte membrane is in a low water content state.
  • the metal phosphate with ionic conductivity compensates for ionic conductivity
  • low cell resistance during power generation (low cell electrical resistance)can be realized.
  • a polymer block having the ion conductivity function of the polymer electrolyte supplements the metal phosphate network, so that sufficient ionic conductivity is exhibited even when the metal phosphates are not in contact with each other.
  • the electrolyte membrane in the electrolyte membrane, an ion conduction mechanism that does not involve water partially develops, and the electroosmosis phenomenon of contained water coordinated to protons is suppressed. It is possible to alleviate the flooding phenomenon that causes diffusion inhibition. Therefore, by using the electrolyte membrane obtained from the electrolyte of the present invention, the fuel cell power generation performance can be improved also from the viewpoint of moisture management. Furthermore, since the polymer block having the flexibility function imparts flexibility to the electrolyte membrane, the moldability of the electrolyte membrane, the mechanical durability, and the bondability with the electrode, which are problematic only with the metal phosphate, are improved. Can do.
  • the electrolyte membrane obtained by using the electrolyte of Embodiments 1 and 3 of the present invention has excellent ionic conductivity under low humidity conditions, improves the power generation output of a fuel cell using hydrogen that operates under low humidity conditions, and DMFC The MCO can be reduced and the power generation output can be improved.
  • the electrolyte membrane is excellent in flexibility, moldability, and processability, and has high mechanical durability. Therefore, the membrane-electrode assembly using the electrolyte membrane has excellent performance in a polymer electrolyte fuel cell operating under low humidity conditions using hydrogen as a fuel, and a polymer electrolyte fuel cell using an aqueous methanol solution as a fuel. Can be demonstrated.
  • the electrolyte is used as a binder used to take charge of ion conduction inside the electrode and binding of the catalyst in the fuel cell electrode catalyst layer from the viewpoint of low resistance under low humidity conditions, suppression of MCO and water management of the fuel cell. It is also possible to use it.
  • aspect 3 of the present invention in addition to the above, by controlling the particle size of the metal phosphate, elution of phosphoric acid from the metal phosphate can be reduced, so that the durability of the electrolyte membrane is improved.
  • the electrolyte membrane obtained by using the electrolyte of aspect 2 of the present invention has excellent ionic conductivity under low humidity conditions, improves the power generation output of a fuel cell using hydrogen that operates under low humidity conditions, and is 100 ° C. or higher. It exhibits high ionic conductivity even under high temperature and low humidity conditions.
  • the electrolyte membrane is excellent in flexibility, moldability, and processability, and has high mechanical durability. Therefore, the membrane-electrode assembly using the electrolyte membrane can exhibit excellent performance in a fuel cell that uses hydrogen as a fuel and operates under low humidity conditions and high temperature non-humidified conditions.
  • the electrolyte can also be used as a binder for an electrolyte membrane for a fuel cell using a methanol aqueous solution as a fuel, and a fuel cell electrode catalyst layer from the viewpoint of high ion conductivity and moisture management of the fuel cell. .
  • the block copolymer constituting the polymer electrolyte of the present invention is a block copolymer comprising polymer blocks (A) and (B) that are phase-separated from each other, and the polymer block (A) is an ion. It has a conductive group, the polymer block (B) forms a flexible phase, and the ion conductive group is a block copolymer which exists substantially only in the polymer block (A).
  • the block copolymer can be a polymer skeleton such as an addition polymerization polymer, a polycondensation polymer, a polyaddition polymer, a vinyl polymer, a polyurethane, a polyether, a polysiloxane, a polyester, Polyamide, polycarbonate, polysulfide, polyamine, polysilane, polyazomethine, polyhydrazide, polyanhydride, polythioester, polythiocarbonate, polythioamide, polyphosphonate, polysulfonamide, polyphosphonate ester, polyphosphate ester, polyphosphonamide, polyphenylene , Polyketone, polysulfone, polyamideimide, polyimide, polyetheramide, polybenzoazole, polyoxazole, polythiazole, polyimidazole, polypyrazole, polyoxadiazole, polytriazol , One or more polymer blocks (A) and polymer blocks each selected from the group consisting of polytria
  • the block copolymer is synthesized by addition polymerization, coordination polymerization, group transfer polymerization, photopolymerization, radiation polymerization, polycondensation, ring-opening polymerization, polyaddition, electrolytic polymerization, oxidation polymerization, or the like.
  • a vinyl block copolymer is preferable because of the simplicity of precision polymerization and the variety of applicable polymerization techniques.
  • an aromatic vinyl polymer block (Aa) mainly composed of aromatic vinyl compound units is preferable.
  • the aromatic vinyl compound unit constituting the aromatic vinyl polymer block (Aa) the following general formula (I)
  • Ar represents an aryl group having 6 to 14 carbon atoms which may have 1 to 3 substituents
  • R 1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 1 to 3 carbon atoms.
  • the main repeating unit may be comprised from 1 type chosen from the unit represented by general formula (I), and may be comprised from 2 or more types.
  • Examples of the aryl group having 6 to 14 carbon atoms in the definition of Ar include a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, an indenyl group, and a biphenylyl group.
  • the substituents are each independently a linear or branched alkyl group having 1 to 4 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group).
  • alkyl group having 1 to 4 carbon atoms in the definition of R 1 may be linear or branched, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group.
  • Examples of the aryl group having 6 to 14 carbon atoms in the definition of R 1 include those similar to the aryl group having 6 to 14 carbon atoms that may have 1 to 3 substituents in the definition of Ar. .
  • R 1 is an alkyl group having 1 to 4 carbon atoms
  • Ar preferably has no substituent, but when it has a substituent, the number of substituents is 1 or 2. Preferably, it is one.
  • R 1 is an aryl group having 6 to 14 carbon atoms, it is most preferred that both or one of the aryl group and Ar do not have a substituent, but when both have a substituent, The number is preferably 1 or 2, and more preferably 1.
  • aromatic vinyl compound capable of constituting the aromatic vinyl compound unit by polymerization examples include styrene, vinyl naphthalene, vinyl anthracene, vinyl phenanthrene, vinyl biphenyl, ⁇ -methyl styrene, 1-methyl-1-naphthyl ethylene, Examples thereof include 1-methyl-1-biphenylylethylene, and styrene and ⁇ -methylstyrene are particularly preferable.
  • the above aromatic vinyl compounds may be used alone or in combination of two or more.
  • the form in the case of copolymerizing two or more types may be random copolymerization, block copolymerization, graft copolymerization, or tapered copolymerization.
  • the aromatic vinyl polymer block (Aa) may contain one or more other monomer units in addition to the aromatic vinyl compound unit as long as the effects of the present invention are not impaired.
  • Examples of the monomer that gives such other monomer unit include conjugated alkadienes having 4 to 8 carbon atoms (specific examples are the same as those in the description of the polymer block (B) described later), and alkenes having 2 to 8 carbon atoms.
  • (meth) acrylate esters (methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc.), vinyl Examples include esters (vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, etc.), vinyl ethers (methyl vinyl ether, isobutyl vinyl ether, etc.), and the like.
  • the copolymerization form of the aromatic vinyl compound and the other monomer needs to be random copolymerization.
  • the ratio of the aromatic vinyl compound unit contained in the aromatic vinyl polymer block (Aa) is preferably 50 mol% or more, and preferably 60 mol% or more from the viewpoint of imparting sufficient ion conductivity. Is more preferable, and it is still more preferable that it is 80 mol% or more.
  • the molecular weight of the polymer block (A) in the state where the ion conductive group is not introduced is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, etc., but the number average molecular weight in terms of polystyrene In general, it is preferably selected from 100 to 1,000,000, and more preferably selected from 500 to 100,000.
  • the polymer block (A) may be crosslinked by a known method within a range not impairing the effects of the present invention. By introducing the cross-linking, the ion channel phase formed by the polymer block (A) becomes difficult to swell, and the change in mechanical properties (such as tensile properties) between dry and wet tends to be small.
  • the block copolymer used in the polymer electrolyte of the present invention has, in addition to the polymer block (A), a polymer block (B) that forms a flexible phase and has substantially no ion conductive group.
  • a compound unit capable of forming a flexible phase is selected as the main repeating compound unit of the polymer block (B).
  • the block copolymer becomes elastic and flexible as a whole, and formability (assembly property) in the production of membrane-electrode assemblies and polymer electrolyte fuel cells. , Bondability, tightenability, etc.) are improved.
  • the polymer block (B) here is a so-called rubber-like polymer block having a glass transition point or softening point of 50 ° C. or lower, preferably 20 ° C. or lower, more preferably 10 ° C. or lower.
  • the polymer block (B) forms a flexible phase and has substantially no ion conductive group.
  • the block (Ba) is used.
  • the vinyl compound units that can constitute the vinyl polymer block (Ba) include alkene units having 2 to 8 carbon atoms, cycloalkene units having 5 to 8 carbon atoms, vinyl cycloalkene units having 7 to 10 carbon atoms, carbon Examples thereof include conjugated alkadiene units having 4 to 8 carbon atoms, conjugated cycloalkadiene units having 5 to 8 carbon atoms, acrylic acid ester units, vinyl ester units, and vinyl ether units.
  • the vinyl compounds giving these units can be used alone or in combination of two or more.
  • the form in the case of copolymerizing two or more types may be random copolymerization, block copolymerization, graft copolymerization, or tapered copolymerization.
  • the monomer to be used for (co) polymerization has two carbon-carbon double bonds, any of them may be used for the polymerization, and some or all of the double bonds remaining after the polymerization are hydrogen.
  • the monomer when it is a conjugated alkadiene, it may be a 1,2-bond, a 3,4-bond or a 1,4-bond, and has a glass transition point. If the softening point is 50 ° C. or lower, there is no particular limitation on the ratio of 1,2-bonds or 3,4-bonds to 1,4-bonds.
  • the vinyl polymer block (Ba) has a carbon number from the viewpoint of giving the obtained block copolymer flexibility, elasticity, and good moldability in the production of a membrane-electrode assembly and a polymer electrolyte fuel cell. From 2 to 8 alkene units, 5 to 8 carbon cycloalkene units, 7 to 10 vinyl cycloalkene units, 4 to 8 conjugated alkadiene units, and 5 to 8 conjugated cycloalkadiene units. A polymer block having at least one selected as a main repeating unit is preferred, and at least one selected from an alkene unit having 4 to 8 carbon atoms and a conjugated alkadiene unit having 4 to 8 carbon atoms is used as a main repeating unit.
  • the polymer block is a small amount selected from alkene units having 4 to 6 carbon atoms and conjugated alkadiene units having 4 to 8 carbon atoms. Also it is more preferable one is a polymer block whose main repeating unit.
  • the most preferred alkene unit is an isobutene unit, an amorphous hydrogenated 1,3-butadiene unit (an optionally mixed 1-butene unit or a 2-butene unit), a hydrogenated isoprene unit (a mixed one).
  • the most preferable conjugated alkadiene unit is an amorphous 1,3-butadiene unit. And / or isoprene units.
  • the monomer that can constitute the repeating unit contains a plurality of carbon-
  • the carbon-carbon double bond usually remains in the polymer after polymerization.
  • carbon-carbon double bonds remain in the polymer in this way, such a point is required from the viewpoint of improving the power generation performance and heat resistance deterioration of the membrane-electrode assembly using the polymer electrolyte membrane of the present invention.
  • More than 30 mol% of the carbon-carbon double bond is preferably hydrogenated, more preferably 50 mol% or more is hydrogenated, more preferably 80 mol% or more is hydrogenated. Even more preferred.
  • the hydrogenation rate of the carbon-carbon double bond can be calculated by a commonly used method, for example, iodine value measurement method, 1 H-NMR measurement or the like.
  • Alkenes having 2 to 8 carbon atoms include ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene, 2-heptene and 1-octene.
  • cyclooctene having 5 to 8 carbon atoms include cyclopentene, cyclohexene, cycloheptene and cyclooctene, and vinylcycloalkene having 7 to 10 carbon atoms include vinylcyclopentene, vinylcyclohexene and vinylcyclohexane. Heptene, vinylcyclooctene, etc. are mentioned.
  • Examples of the conjugated alkadiene having 4 to 8 carbon atoms include 1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4-hexadiene, 2,3 -Dimethyl-1,3-butadiene, 2-ethyl-1,3-butyl Diene, 1,3-heptadiene, 1,4-heptadiene, 3,5-heptadiene and the like, cyclopentadiene, 1,3-cyclohexadiene, and the like as a conjugated cycloalkadiene having 5 to 8 carbon atoms.
  • Examples of the acrylate ester include methyl acrylate, ethyl acrylate, and butyl acrylate.
  • Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl pivalate.
  • Examples of the vinyl ether include methyl vinyl ether. And isobutyl vinyl ether.
  • the vinyl polymer block (Ba) does not impair the purpose of the polymer block (B) that gives the block copolymer flexibility and elasticity other than the vinyl compound unit capable of forming the flexible phase. It may contain other monomer units, for example, halogen-containing vinyl compound units such as aromatic vinyl compound units and vinyl chloride units. In this case, it is necessary that the copolymerization form of the vinyl compound capable of forming the flexible phase and the other monomer is random copolymerization.
  • the amount of the other monomer used is preferably less than 50% by mass and less than 30% by mass with respect to the total of the vinyl compound capable of forming the flexible phase and the other monomer. Is more preferable, and it is still more preferable that it is less than 10 mass%.
  • the block copolymer constituting the polymer electrolyte of the present invention is different from the polymer block (A) and the polymer block (B), and is phase-separated from these and has substantially no ion conductive group. It is a polymer block, Comprising: The polymer block (C) which functions as a constrained phase may be included.
  • the polymer block (C) when the block copolymer is a vinyl block copolymer, for example, a polymer block having an aromatic vinyl compound unit as a main repeating unit, a crystalline polyolefin block and the like can be mentioned. It is done.
  • the polymer block (C) By causing the polymer block (C) to function as a constraining phase, it is possible to reduce dimensional changes and changes in mechanical properties (such as tensile strength) caused by repetition of operation and stop of the polymer electrolyte fuel cell, Changes in methanol permeability, ionic conductivity, and the like before and after power generation in a direct methanol solid polymer fuel cell can be reduced.
  • mechanical properties such as tensile strength
  • the aromatic vinyl compound unit in the case of constituting the main repeating unit in the polymer block (C) is represented by the general formula (II)
  • R 2 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, at least one of which is an alkyl group having 1 to 8 carbon atoms, and R 5 represents a hydrogen atom or a carbon atom
  • the alkyl group having 1 to 8 carbon atoms includes methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, Examples include linear alkyl groups such as octyl group, branched alkyl groups such as isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, and 1-methylpentyl group.
  • the alkyl group having 1 to 4 carbon atoms includes a straight chain alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, a branched group such as an isopropyl group, an isobutyl group and a tert-butyl group.
  • Preferable specific examples of the aromatic vinyl compound unit represented by the general formula (II) include p-methylstyrene unit, 4-tert-butylstyrene unit, p-methyl- ⁇ -methylstyrene unit, 4-tert- Examples include butyl- ⁇ -methylstyrene unit.
  • aromatic vinyl compounds giving an aromatic vinyl compound unit may be used alone or in combination of two or more.
  • the form in the case of copolymerizing two or more types may be random copolymerization, block copolymerization, graft copolymerization, or tapered copolymerization.
  • the polymer block (C) has an aromatic vinyl compound unit as a main repeating unit
  • the polymer block (C) has a monomer unit other than the aromatic vinyl compound unit as a binding phase.
  • the monomer which may be contained within the range not impeding the function and gives other monomer units is, for example, a conjugated alkadiene having 4 to 8 carbon atoms (specific examples are the polymer block (B) described above) ), (Meth) acrylate ester (methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc.), vinyl ester (vinyl acetate, vinyl propionate, vinyl butyrate, Vinyl pivalate, etc.) and vinyl ether (methyl vinyl ether, isobutyl vinyl ether, etc.).
  • the copolymerization form of the aromatic vinyl compound and the other monomer needs to be random copolymerization.
  • the aromatic vinyl compound unit described above preferably accounts for 50 mol% or more, more preferably 70 mol% or more of the polymer block (C), and more preferably 90 mol%. It is even more preferable to occupy% or more.
  • the polymer block (C) is composed of a crystalline polyolefin block
  • examples of the crystalline polyolefin block include a crystalline polyethylene block, a crystalline polypropylene block, a crystalline hydrogenated 1,4-polybutadiene block, and the like. Of these, crystalline hydrogenated 1,4-polybutadiene blocks are most preferred.
  • examples of the polymer block (C) that are particularly suitable include poly p Polystyrene blocks such as methylstyrene block, poly-4- (tert-butyl) styrene block, poly p-methyl- ⁇ -methylstyrene block, poly-4-tert-butyl- ⁇ -methylstyrene block; A copolymer obtained by copolymerizing two or more selected from alkyl-substituted styrenes such as p-methylstyrene, 4- (tert-butyl) styrene, p-methyl- ⁇ -methylstyrene, and 4-tert-butyl- ⁇ -methylstyrene.
  • the molecular weight of the polymer block (C) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like. When the molecular weight is large, the mechanical properties of the polymer electrolyte tend to be high, but when it is too large, it becomes difficult to mold the block copolymer, and when the molecular weight is small, the mechanical properties tend to be low, and the required performance is reduced. It is important to select the molecular weight accordingly.
  • the number average molecular weight in terms of polystyrene is usually preferably selected from 100 to 1,000,000, more preferably from 1,000 to 100,000.
  • the structure of the block copolymer composed of the polymer block (A), the polymer block (B) and the polymer block (C) is not particularly limited, but examples include an AB diblock copolymer, A -BA type triblock copolymer, BAB type triblock copolymer, ABC type triblock copolymer, ABC type tetrablock copolymer, A- BAC type tetrablock copolymer, BABC type tetrablock copolymer, ABCB type tetrablock copolymer, CBCA type tetrablock copolymer Copolymer, CABACA type pentablock copolymer, CBAABC type pentablock copolymer, ACCBCA type pentablock copolymer Coalescence, ABCAB-AC type pentablock copolymer, ABBCAB type pentablock Lock copolymer, ABCBC type pentablock copolymer, ABBCBC type pentablock copolymer, ABBABC
  • both ends of at least one B block are bonded to other blocks and are not terminals of the block copolymer. It is preferable to have a plurality of C blocks.
  • the block copolymer used in the present invention includes those partially containing graft bonds.
  • Examples of the block copolymer partially containing a graft bond include those in which a part of the constituting polymer block is grafted to the main part (for example, main chain) of the block copolymer.
  • block copolymer used in the present invention has two or more polymer blocks (A), they may be the same or different in structure and molecular weight. Further, when the block copolymer has two or more polymer blocks (B), they may be the same or different in structure and molecular weight. When the block copolymer has two or more polymer blocks (C), they may be the same or different in structure and molecular weight.
  • the mass ratio of the sum of the polymer block (A) and the polymer block (C) to the polymer block (B) depends on the required performance, flexibility, elasticity, and membrane- It is important to select appropriately from the viewpoint of giving good moldability in the production of the electrode assembly and the polymer electrolyte fuel cell.
  • the mass ratio of the polymer block (B) is too small, the flexibility, elasticity, and moldability are poor, and the electrolyte membrane becomes rigid, so the mechanical durability tends to decrease.
  • the mass ratio of the polymer block (B) and the sum of the polymer block (A) and the polymer block (C) in the electrolyte of the present invention is preferably 90:10 to 10:90, 70:30 to 30:70 is more preferable, and 60:40 to 40:60 is even more preferable.
  • the number average molecular weight of the block copolymer constituting the electrolyte of the present invention in the state where the ion conductive group is not introduced is not particularly limited, but the number average molecular weight in terms of polystyrene is usually 10,000 to 2,000. , Preferably 15,000 to 1,000,000, more preferably 20,000 to 500,000.
  • the block copolymer used in the present invention needs to have an ion conductive group in the polymer block (A).
  • ions in the present invention when referring to ionic conductivity include protons.
  • the ion conductive group is not particularly limited as long as the membrane-electrode assembly produced using the polymer electrolyte membrane can express sufficient ionic conductivity, and among them, —SO 3 M or — A sulfonic acid group, a phosphonic acid group or a salt thereof represented by PO 3 HM (wherein M represents a hydrogen atom, an ammonium ion or an alkali metal ion) is preferably used.
  • a carboxyl group or a salt thereof can also be used.
  • the introduction position of the ion conductive group is set to the polymer block (A) because the introduction of the ion conductive group is easy and the formation of the ion channel is facilitated.
  • the ion conductive group is introduced into the polymer block (A), and even if it is introduced into the aromatic vinyl compound unit which is the main repeating unit, it is introduced into the other monomer units described above. May be. However, from the viewpoint of facilitating ion channel formation and suppression of MCO in DMFC, it is preferably introduced into the aromatic ring of the aromatic vinyl compound unit.
  • the ion conductive group is substantially present only in the polymer block (A). This is in part for facilitating the formation of ion channels and in part for the purpose of substantially limiting the components that form the ion channels to the polymer block (A).
  • ion conductive groups exist at a high density, and high-efficiency ion conduction is possible.
  • the fact that an ion conductive group is present substantially only in the polymer block (A) is 70 mol% or more, preferably 80 mol% or more, more preferably, of the ion conductive group present in the block copolymer. Means 90 mol% or more, more preferably 95 mol% or more is present in the polymer block (A).
  • the amount of ion-conductive group introduced is important in determining the performance of the polymer electrolyte.
  • the ion exchange capacity of the polymer electrolyte of the present invention is 0.30 meq /
  • the amount is preferably such that it is at least g, more preferably at least 0.35 meq / g.
  • the upper limit of the ion exchange capacity is preferably 3.0 meq / g or less, because if the ion exchange capacity becomes too large, hydrophilicity tends to increase and it tends to swell.
  • the block copolymer used in the present invention can be obtained mainly by the following two production methods. That is, (1) a method in which a block copolymer having no ion conductive group is produced and then the ion conductive group is bonded; (2) a block copolymer using a monomer having an ion conductive group It is a method of manufacturing.
  • the polymer block (A), (A), (B) or (C) may be polymer block (A), (B) or (C) is appropriately selected from a radical polymerization method, an anionic polymerization method, a cationic polymerization method, a coordination polymerization method and the like, but from the viewpoint of industrial ease, a radical polymerization method, an anionic polymerization or a cation.
  • a polymerization method is preferably selected.
  • a so-called living polymerization method is preferred from the viewpoint of molecular weight, molecular weight distribution, polymer structure, ease of bonding of polymer blocks (A), (B) and (C), and specifically, a living radical polymerization method or a living Anionic polymerization and living cationic polymerization are preferred.
  • Specific examples of the production method include a polymer block (C) having an aromatic vinyl compound such as 4-tert-butylstyrene as a main repeating unit, a polymer block (A) comprising styrene or ⁇ -methylstyrene, and a conjugated alkadiene.
  • An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 100 ° C. using an anionic polymerization initiator in a cyclohexane solvent, and then conjugated alkadiene and styrene are sequentially polymerized.
  • a method of obtaining an ABC type block copolymer (2) Polymerizing an aromatic vinyl compound such as 4-tert-butylstyrene using an anionic polymerization initiator in a cyclohexane solvent at a temperature of 10 to 100 ° C., and then sequentially polymerizing styrene and conjugated alkadiene And then adding a coupling agent such as phenyl benzoate to obtain a CABAC type block copolymer, (3) using an anionic polymerization initiator in a cyclohexane solvent under a temperature condition of 10 to 100 ° C., an aromatic vinyl compound such as 4-tert-butylstyrene, a conjugated alkadiene, 4-tert-butylstyrene, etc.
  • an aromatic vinyl compound such as 4-tert-butylstyrene, a conjugated alkadiene, 4-tert-butylstyrene, etc.
  • CBC block copolymer is prepared by sequential polymerization of aromatic vinyl compounds, and anionic polymerization initiator system (anionic polymerization initiator / N, N, N ′, N′-tetramethylethylenediamine) is added. And then lithiating the conjugated alkadiene unit and then polymerizing styrene to obtain a CB (-gA) -C type block / graft copolymer,
  • a concentration of 5 to 50% by mass ⁇ -methylstyrene is polymerized, and the resulting living polymer is polymerized with an aromatic vinyl compound such as 4-tert-butylstyrene and a conjugated alkadiene, and then a coupling agent such as phenyl benzoate is added to form A- A method of obtaining a CBCA type block copolymer can be employed / applied.
  • a method for bonding an ion conductive group to the resulting block copolymer will be described.
  • a method for introducing a sulfonic acid group into the obtained block copolymer will be described.
  • Sulfonation can be performed by a known sulfonation method.
  • an organic solvent solution or suspension of a block copolymer is prepared, a sulfonating agent is added and mixed, a method of adding a gaseous sulfonating agent directly to the block copolymer, etc. Is exemplified.
  • Sulfonating agents used include sulfuric acid, a mixture of sulfuric acid and aliphatic acid anhydride, chlorosulfonic acid, a mixture of chlorosulfonic acid and trimethylsilyl chloride, sulfur trioxide, a mixture of sulfur trioxide and triethyl phosphate.
  • aromatic organic sulfonic acids represented by 2,4,6-trimethylbenzenesulfonic acid.
  • organic solvent to be used include halogenated hydrocarbons such as methylene chloride, linear aliphatic hydrocarbons such as hexane, cyclic aliphatic hydrocarbons such as cyclohexane, and the like. You may use it, selecting suitably from several combinations.
  • Phosphonation can be performed by a known phosphonation method. Specifically, for example, an organic solvent solution or suspension of a block copolymer is prepared, and the copolymer is reacted with chloromethyl ether or the like in the presence of anhydrous aluminum chloride to introduce a halomethyl group into the aromatic ring. Thereafter, there may be mentioned a method in which phosphorus trichloride and anhydrous aluminum chloride are added and reacted, followed by a hydrolysis reaction to introduce a phosphonic acid group.
  • a method may be exemplified in which phosphorus trichloride and anhydrous aluminum chloride are added to the copolymer and reacted to introduce a phosphinic acid group into the aromatic ring, and then the phosphinic acid group is oxidized with nitric acid to form a phosphonic acid group.
  • the degree of sulfonation or phosphonation is such that the ion exchange capacity of the polymer electrolyte of the present invention is 0.30 meq / g or more, particularly 0.35 meq / g or more, but 3.00 meq. It is desirable to sulfonate or phosphonate so that it is less than / g. Thereby, practical ion conduction performance is obtained.
  • the ion exchange capacity of the finally obtained polyelectrolyte, the ion exchange capacity of the sulfonated or phosphonated block copolymer, or the sulfonation rate or phosphonation rate in the polymer block (A) in the block copolymer can be calculated using analytical means such as acid value titration method, infrared spectroscopic spectrum measurement, nuclear magnetic resonance spectrum ( 1 H-NMR spectrum) measurement.
  • the second production method of the block copolymer used in the present invention is a method of producing a block copolymer using at least one monomer having an ion conductive group.
  • the monomer having an ion conductive group is preferably a monomer in which an ion conductive group is bonded to an aromatic vinyl compound.
  • a monomer in which an ion conductive group is bonded to a conjugated alkadiene compound can also be used.
  • Examples of the monomer containing an ion conductive group include vinyl sulfonic acid, ⁇ -alkyl-vinyl sulfonic acid, vinyl alkyl sulfonic acid, ⁇ -alkyl-vinyl alkyl sulfonic acid, vinyl phosphonic acid, ⁇ -alkyl-vinyl phosphone. Acid, vinyl alkyl phosphonic acid, ⁇ -alkyl-vinyl alkyl phosphonic acid and the like can also be used.
  • a (meth) acrylic monomer to which an ion conductive group is bonded can also be used. Specific examples include methacrylic acid, acrylic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid and the like.
  • the ion conductive group may be introduced in the form of a salt neutralized with a suitable metal ion (for example, alkali metal ion) or counter ion (for example, ammonium ion).
  • a suitable metal ion for example, alkali metal ion
  • counter ion for example, ammonium ion
  • a group can be introduced.
  • the block copolymer which made the sulfonic acid group into the salt form can be obtained by ion-exchange by a suitable method.
  • the metal phosphate used in the present invention is, as a raw material, M (where M is one or more elements selected from the group consisting of elements of groups 4 and 14 of the long-period periodic table) And a compound containing J (where J is one or more elements selected from the group consisting of elements of Group 3, Group 13, Group 5 and Group 15 of the Long Periodic Periodic Table) And a compound containing P) and a compound containing P.
  • M is one or more elements selected from the group consisting of elements of groups 4 and 14 of the long-period periodic table
  • J is one or more elements selected from the group consisting of elements of Group 3, Group 13, Group 5 and Group 15 of the Long Periodic Periodic Table
  • P a compound containing P
  • the metal phosphate is preferably substantially represented by the following formula (1): M 1-x J x P 2 O 7 (1) (Wherein x represents a numerical value of 0.001 to 0.5, and M and J are as defined above).
  • composition ratio of the formula (1) that is, the molar ratio of M: J: P: O (1-x): x: 2: 7.
  • the amount is usually within about ⁇ 10%, that is, the molar ratio of phosphorus atoms is 1.8 to 2.2, and the molar ratio of oxygen atoms is 6.3 to 7 It means that it may vary independently within the range of .7. It is. However, the degree of increase / decrease is preferably as small as possible.
  • M examples include Ti, Zr, Hf, etc. as metals belonging to Group 4, and Si, Ge, Sn, Pb, etc., as metals belonging to Group 14, and J, as metals belonging to Group 3 As metals belonging to Group 15, such as Sc, Y, La, Ce, Yb, etc., B, Al, Ga, In, etc. as metals belonging to Group 13, V, Nb, Ta, etc. as metals belonging to Group 5 Sb, Bi and the like.
  • M is preferably Ti, Zr, Hf, Si, Ge, Sn and Pb, and J is preferably Al and In.
  • the compound containing M may be appropriately selected depending on the kind of M, but an oxide is used, or decomposition and / or oxidation is performed at a high temperature such as hydroxide, carbonate, nitrate, halide, oxalate, etc.
  • an oxide capable of becoming an oxide can be used.
  • compounds containing M include titanium (IV) chloride, titanium (IV) iodide, titanium (IV) oxide, titanium (IV) ethoxide, zirconium bromide (IV ), Zirconium chloride (IV), zirconium oxide (IV), zirconium carbonate (IV), zirconium (IV) ethoxide, germanium bromide (IV), germanium iodide (IV), germanium oxide (IV), tin acetate (IV) ), Tin (IV) fluoride, tin (IV) chloride, tin (IV) bromide, tin (IV) iodide, tin (IV) oxide, and hydrates thereof.
  • oxides or hydrates thereof can be preferably used from the viewpoint of cost and safety of by-products generated by decomposition and / or oxidation at high temperature.
  • Examples of the compound containing P include phosphoric acid and phosphonic acid, and phosphoric acid is preferable from the viewpoint of reactivity with M and J.
  • phosphoric acid is preferable from the viewpoint of reactivity with M and J.
  • a supply source of phosphoric acid a concentrated phosphoric acid aqueous solution of 50% or more is usually used, but an 80 to 90% concentrated phosphoric acid aqueous solution is preferable from the viewpoint of operability.
  • the compound containing J may be appropriately selected from known compounds. Specifically, an oxide is used, or a hydroxide, halide, nitrate, acetate, carbonate, alkoxide (ethoxide, Isopropoxide or the like), oxalate, or the like that can be decomposed and / or oxidized at high temperature to form an oxide may be used.
  • an oxide is used, or a hydroxide, halide, nitrate, acetate, carbonate, alkoxide (ethoxide, Isopropoxide or the like), oxalate, or the like that can be decomposed and / or oxidized at high temperature to form an oxide may be used.
  • compounds containing J include scandium acetate (III), scandium carbonate (III), scandium fluoride (III), Scandium chloride (III), scandium iodide (III), scandium nitrate (III), scandium oxide (III), yttrium acetate (III), yttrium fluoride (III), yttrium chloride (III), yttrium bromide (III) , Yttrium nitrate (III), yttrium oxalate (III), yttrium oxide (III), yttrium (III) isopropoxide, lanthanum acetate, lanthanum carbonate (III), lanthanum fluoride (III), lanthanum chloride (III), Lanthanum (III) bromide, lanthanum iodide (III), lanthanum nitrate (III), lanthanum o
  • a metal phosphate can be produced by including the following steps (a) and (b) in this order: (A) a step of reacting a compound containing M, a compound containing J and a compound containing P, such as phosphoric acid, to obtain a reaction product, (B) A step of heat-treating the reactant.
  • the reaction temperature is appropriately selected depending on the composition of the metal phosphate to be synthesized, and is usually performed at a temperature in the range of 200 to 400 ° C.
  • the temperature is in the range of 250 to 350 ° C.
  • M contains Ti, Zr, Ge, or Sn
  • J contains Sc, Y, La, Yb, B, Al, Ga, In, or Bi In this case, 270 to 330 ° C. is more preferable.
  • the reaction time is appropriately selected according to the composition of the metal phosphate to be synthesized, and should be as long as possible. However, in consideration of productivity, it is preferably in the range of 1 to 50 hours, M contains Ti, Zr, Ce or Sn, and J contains Sc, Y, La, Yb, B, Al, Ga, When In or Bi is contained, it is more preferably in the range of 1 to 20 hours.
  • the reactant obtained in the step (a) is a paste, and the metal phosphate can be obtained by heat-treating the reactant in the step (b).
  • the temperature of the heat treatment is appropriately selected depending on the composition of the metal phosphate to be synthesized, and is preferably in the range of 500 to 800 ° C., when M is Ti, Zr, Ge or Sn, and / or J is Sc. , Y, La, Yb, B, Al, Ga, In, or Bi, a range of 600 to 700 ° C. is more preferable, and a range of 630 to 680 ° C. is even more preferable.
  • the heat treatment time is appropriately selected according to the composition of the metal phosphate to be synthesized, and is preferably in the range of 1 to 20 hours.
  • M is Ti, Zr, Ge or Sn, and / or J is Sc
  • the range of 1 to 5 hours is more preferable, and the range of 2 to 5 hours is even more preferable.
  • the mass ratio of the electrolyte constituting the first aspect of the present invention, and thus the copolymer constituting the electrolyte membrane and the metal phosphate, should be appropriately selected from the viewpoint of required performance such as film formability, membrane strength, ionic conductivity, and MCO. is important.
  • the mass ratio of the metal phosphate is too small, the effect of improving the ionic conductivity tends to be insufficient.
  • the mass ratio of the metal phosphate is too large, the membrane strength, dimensional stability, and morphological stability of the electrolyte membrane tend to decrease when wet.
  • the mass ratio of the copolymer and the metal phosphate in the electrolyte and thus the electrolyte membrane of Embodiment 1 of the present invention is preferably 99: 1 to 30:70, and 70:30 to 30:70 is More preferably, it is more preferably 50:50 to 30:70.
  • the mass ratio of the electrolyte constituting the second aspect of the present invention that is, the copolymer constituting the electrolyte membrane and the metal phosphate is appropriately selected from the viewpoint of required performance such as film formability, membrane strength, and ionic conductivity. It is. When the mass ratio of the metal phosphate is too small, the effect of improving the ionic conductivity tends to be insufficient. On the other hand, when the mass ratio of the metal phosphate is too large, the membrane strength, dimensional stability, and morphological stability of the electrolyte membrane tend to decrease when wet.
  • the electrolyte of Embodiment 2 of the present invention is preferably 80:20 to 1:99, more preferably 70:30 to 5:95, and 50:50 to 10:90. Even more preferred.
  • the mass ratio of the copolymer constituting the electrolyte of Embodiment 3 of the present invention and the electrolyte membrane to the metal phosphate is not limited to the required performance such as film formability, membrane strength, ionic conductivity, MCO, etc. It is important to select appropriately according to the operating conditions of the fuel cell to be used. If the mass ratio of the metal phosphate is too small, the effect of improving the ionic conductivity tends to be insufficient, and if the mass ratio of the metal phosphate is too large, the membrane strength of the electrolyte membrane when wet, Dimensional stability and form stability tend to decrease. From the above viewpoint, a fuel cell that operates at a temperature of 100 ° C.
  • the mass ratio of the copolymer and the metal phosphate in the electrolyte and thus the electrolyte membrane of the embodiment 3 of the present invention is preferably 99: 1 to 30:70, and 70:30 to 30:70. Is more preferably 50:50 to 30:70.
  • a fuel cell that operates at a temperature of 100 ° C.
  • the mass ratio of phosphate is preferably 80:20 to 1:99, more preferably 70:30 to 5:95, and still more preferably 50:50 to 10:90.
  • the particle size of the metal phosphate constituting the electrolyte of aspect 3 of the present invention is preferably selected as appropriate from the viewpoints of film strength and moldability in addition to required performance such as ion conductivity and MCO.
  • the particle size of the metal phosphate is too large, the contact area with the ion channel of the copolymer is reduced, and the distance between the metal phosphate particles is increased, so that the ion conduction efficiency tends to be reduced. .
  • the roughness and unevenness of the electrolyte membrane surface are increased, the bondability with the electrode is lowered, and the contact resistance generated at the interface between the electrode and the electrolyte membrane is increased.
  • the average particle diameter of the metal phosphate in the electrolyte of Embodiment 3 of the present invention needs to be 10 nm to 1 ⁇ m, preferably 20 nm to 500 nm, and preferably 30 nm to 300 nm. More preferred.
  • a solution containing a dissolved block polymer and an insoluble metal phosphate is prepared by mixing an electrolyte with a solvent that does not dissolve the metal phosphate but dissolves the block polymer contained in the electrolyte.
  • a treatment for maintaining a good dispersion state of the metal phosphate is performed by an appropriate method.
  • a method of performing measurement after or while performing the treatment (8) Mixing a solvent that does not dissolve the metal phosphate but dissolves the block polymer contained in the electrolyte and the electrolyte, and obtains the metal phosphorus from the solution containing the dissolved block polymer and the metal phosphate that does not dissolve. After recovering only the acid salt, the metal phosphate is sieved, and the average particle size of the metal phosphate is obtained from the obtained particle size distribution.
  • the median diameter of the metal phosphate measured by the static light scattering method of (3) is used as the average particle diameter of the metal phosphate. More specifically, the median diameter of the metal phosphate measured using a particle size measuring apparatus (LA-950 manufactured by HORIBA Co., Ltd.) was used as the average particle diameter of the metal phosphate.
  • the electrolyte of the present invention and the electrolyte membrane are not limited to the effects of the present invention, and various additives such as softeners, stabilizers, light stabilizers, antistatic agents, mold release agents, flame retardants, foaming agents, pigments , Dyes, brighteners, carbon fibers, inorganic fillers and the like may be used alone or in combination of two or more.
  • softener examples include petroleum softeners such as paraffinic, naphthenic or aromatic process oils, paraffin, vegetable oil softeners, plasticizers, and the like.
  • Stabilizers include phenol-based stabilizers, sulfur-based stabilizers, phosphorus-based stabilizers, and the like.
  • the total content of the block copolymer and the metal phosphate in the electrolyte of the present invention, and in the electrolyte membrane is preferably 50% by mass or more, and more preferably 70% by mass or more. 90% by mass or more is even more preferable.
  • Examples of the method for preparing the polymer electrolyte membrane of the present invention using the block copolymer, metal phosphate and additive used in the present invention include the following (c) and (d): A method comprising the steps in this order can be illustrated: (C) The process of obtaining the liquid mixture containing a block copolymer, a metal phosphate, and the additive in the case of using, (d) The process of obtaining an electrolyte membrane using this liquid mixture. In addition, it is also possible to obtain the polymer electrolyte of the present invention without forming a membrane. After the step (c), the polymer electrolyte of the present invention is obtained by performing an operation with reference to the step (d). An electrolyte can be obtained.
  • step (c) the block copolymer constituting the electrolyte of the present invention is mixed with an appropriate solvent to dissolve or suspend the block copolymer, and the solution or suspension is mixed with a metal phosphate and Add additives for use, mechanically stir and knead to break up metal phosphate agglomerates, and then use metal phosphate and copolymer in suspension or copolymer solution A mixed solution in which the additive is uniformly dispersed is prepared.
  • the solvent used at this time is capable of preparing a solution having a viscosity capable of being cast or coated without destroying the structure of the block copolymer, the metal phosphate, and the additive used. If it is, it will not specifically limit.
  • halogenated hydrocarbons such as methylene chloride, aromatic hydrocarbons such as toluene, xylene, and benzene, linear aliphatic hydrocarbons such as hexane and heptane, and cyclic aliphatic carbonization such as cyclohexane.
  • ethers such as hydrogen and tetrahydrofuran
  • alcohols such as methanol, ethanol, propanol, isopropanol, butanol and isobutyl alcohol, and mixed solvents thereof.
  • the molecular weight, the ion exchange capacity, etc. one or more of the solvents exemplified above can be appropriately selected and used.
  • a mixed solution containing the block copolymer and the metal phosphate is mixed with a stirrer, a ball mill, a bead mill, an emulsifier, A method of kneading using a sonicator, a thin-film rotary stirrer, a high-pressure collision type pulverizer, etc., (2) Block copolymer after pulverizing metal phosphate using a collision type pulverizer, a hammer type pulverizer, etc.
  • block copolymer and metal phosphate kneader (mixing roll, kneader, intensive mixer, etc.), uniaxial kneader (single screw extruder, special single screw)
  • An example is a method of preparing a mixed liquid after kneading using an extruder, etc.), a twin-screw kneader (same direction rotary extruder, different direction rotary extruder, rotor type extruder, screw type extruder, etc.)
  • Can Processing may be performed in combination of two or more methods from the methods described above.
  • step (d) the mixture of the copolymer, metal phosphate and additive used in step (c) is cast into a plate-like body such as PET or glass, or a coater or applicator.
  • Etc., and removing the solvent under appropriate conditions a method for obtaining an electrolyte membrane having a desired thickness, and a known method such as hot press molding, roll molding, extrusion molding, etc.
  • An electrolyte membrane can be obtained using a method for obtaining the electrolyte membrane.
  • the conditions for removing the solvent can be arbitrarily selected as long as the conditions allow the solvent to be completely removed at a temperature equal to or lower than the temperature at which ion conductive groups such as sulfonic acid groups in the block copolymer are removed.
  • a plurality of temperatures may be arbitrarily combined, or a combination of ventilation and vacuum may be arbitrarily combined.
  • the solvent is removed under vacuum conditions at 100 ° C. or higher, preferably at 100 to 120 ° C. for about 12 hours. Examples thereof include, but are not limited to, a method of removing the solvent under drying conditions of about several minutes to several hours under a draft of 60 to 140 ° C.
  • a solution or suspension containing the same or different block copolymer or a mixture containing such a block copolymer, a metal phosphate, and an additive when used is newly added on the obtained electrolyte membrane. You may make it laminate
  • the thickness of the membrane made of the electrolyte of the present invention is appropriately selected according to the application.
  • the thickness is preferably about 5 to 200 ⁇ m from the viewpoint of required performance, membrane strength, handling properties, and the like.
  • the film thickness is less than 5 ⁇ m, the mechanical strength of the film and the barrier properties of fuels such as hydrogen gas and methanol tend to be insufficient.
  • the film thickness exceeds 200 ⁇ m, the electric resistance of the film increases and the power generation characteristics of the battery tend to decrease. Therefore, the film thickness is more preferably 10 to 100 ⁇ m, and still more preferably 20 to 60 ⁇ m.
  • a membrane-electrode assembly using the electrolyte membrane of the present invention will be described.
  • a known method can be applied.
  • a catalyst paste containing an ion conductive binder is applied on the gas diffusion layer by a printing method or a spray method and dried.
  • a method of forming a joined body of the catalyst layer and the gas diffusion layer, and then joining a pair of joined bodies to each side of the electrolyte membrane by hot pressing, etc. Is applied to both sides of the electrolyte membrane by a printing method or a spray method, dried to form catalyst layers, and a gas diffusion layer is pressure-bonded to each catalyst layer by hot pressing or the like.
  • a solution or suspension containing an ion conductive binder is applied to both surfaces of the electrolyte membrane and / or the catalyst layer surface of the pair of gas diffusion electrodes, and the electrolyte membrane and the catalyst layer surface are bonded to each other, There is a method of joining by pressure bonding or the like.
  • the solution or suspension may be applied to either the electrolyte membrane or the catalyst layer surface, or may be applied to both.
  • the catalyst paste is applied to a base film made of polytetrafluoroethylene (PTFE) and dried to form a catalyst layer, and then a pair of base films on the base film is formed.
  • PTFE polytetrafluoroethylene
  • an ion conductive group may be in a salt state with a metal such as Na, and a treatment for returning to a proton type by acid treatment after bonding may be performed.
  • Examples of the ion conductive binder constituting the membrane-electrode assembly include existing perfluorocarbon sulfones such as “Nafion” (registered trademark, manufactured by DuPont) and “Gore-select” (registered trademark, manufactured by Gore).
  • An ion conductive binder made of an acid polymer, an ion conductive binder made of sulfonated polyethersulfone or sulfonated polyetherketone, an ion conductive binder made of polybenzimidazole impregnated with phosphoric acid or sulfuric acid can be used. .
  • an ion conductive binder from the block copolymer which is a main component of the electrolyte of this invention.
  • an ion conductive binder having the same or similar structure as the electrolyte membrane in contact with the gas diffusion electrode.
  • the constituent material of the catalyst layer of the membrane-electrode assembly is not particularly limited as the conductive material / catalyst support, and examples thereof include carbon materials.
  • the carbon material include carbon black such as furnace black, channel black, and acetylene black, activated carbon, graphite, and the like. These may be used alone or in combination of two or more.
  • the catalyst metal may be any metal that promotes the oxidation reaction of fuel such as hydrogen and methanol and the reduction reaction of oxygen, such as platinum, gold, silver, palladium, iridium, rhodium, ruthenium, iron, Cobalt, nickel, chromium, tungsten, manganese, palladium, etc., or alloys thereof, for example, platinum-ruthenium alloy can be mentioned.
  • the particle size of the metal serving as a catalyst is usually 10 to 300 angstroms. It is more advantageous in terms of cost if these catalysts are supported on a conductive material such as carbon / catalyst support because the amount of catalyst used can be reduced.
  • the catalyst layer may contain a water repellent as necessary. Examples of the water repellent include various thermoplastic resins such as polytetrafluoroethylene, polyvinylidene fluoride, styrene-butadiene copolymer, and polyetheretherketone.
  • the gas diffusion layer of the membrane-electrode assembly is made of a material having conductivity and gas permeability, and examples of such a material include porous materials made of carbon fibers such as carbon paper and carbon cloth. Moreover, in order to improve water repellency, this material may be subjected to water repellency treatment.
  • the membrane-electrode assembly of the present invention uses a pure hydrogen type using hydrogen as a fuel gas, a methanol reforming type using hydrogen obtained by reforming methanol, and hydrogen obtained by reforming natural gas. Natural gas reforming type, gasoline reforming type using hydrogen obtained by reforming gasoline, direct methanol type using methanol directly, etc. is there.
  • the fuel cell using the electrolyte membrane of the present invention it is possible to reduce the cell resistance and increase the output under the low humidity condition, and also to reduce the MCO and increase the output in the DMFC.
  • SBS block copolymer
  • SBS polystyrene-b-polybutadiene-b-polystyrene
  • the number average molecular weight of the obtained SBS was 69700, the 1,4-bond content determined from 1 H-NMR measurement was 60.4%, and the content of styrene units was 39.6% by mass.
  • a hydrogenation reaction was carried out at 50 ° C. for 7 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst.
  • SEBS polystyrene-b-hydrogenated polybutadiene-b-polystyrene
  • Poly (4-tert-butylstyrene) -b-polystyrene-b-polyisoprene-b-polystyrene-b- was sequentially added in the order of 0 ml and 2-8.3 ml of 4-tert-butylstyrene and polymerized at 50 ° C.
  • Poly (4-tert-butylstyrene) (hereinafter tBSSIStBS If the abbreviated there) was synthesized.
  • the number average molecular weight (GPC measurement, polystyrene conversion) of the obtained tBSSIStBS is 102800, the 1,4-bond content determined from 1 H-NMR measurement is 93.7%, the styrene unit content is 11% by mass, The content of 4-tert-butylstyrene units was 42% by mass.
  • a cyclohexane solution of synthesized tBSSIStBS was prepared, charged into a pressure-resistant vessel that had been sufficiently purged with nitrogen, and then subjected to a hydrogenation reaction at 60 ° C. for 7 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst.
  • tBSSEPStBS Poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter sometimes abbreviated as tBSSEPStBS) Got.
  • the hydrogenation rate of the obtained tBSSEPStBS was calculated by 1 H-NMR spectrum measurement and found to be 99.9%.
  • the number average molecular weight (GPC measurement, polystyrene conversion) of the obtained tBSSIStBS is 102500, the 1,4-bond content determined from 1 H-NMR measurement is 93.8%, the styrene unit content is 24% by mass, The content of 4-tert-butylstyrene units was 27% by mass.
  • Reference example 4 Synthesis of Sulfonated SEBS A sulfonating reagent was prepared by reacting acetic anhydride 76.7 ml and sulfuric acid 34.3 ml at 0 ° C. in 153 ml of methylene chloride. On the other hand, 100 g of SEBS obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen. I let you. After dissolution, the sulfonation reagent was gradually added dropwise over 5 minutes. After stirring for 8 hours at 35 ° C., the polymer solution was poured into 2 L of distilled water while stirring to coagulate and precipitate the polymer.
  • the precipitated solid was washed with distilled water at 90 ° C. for 30 minutes, and then filtered. This washing and filtration operation was repeated until there was no change in the pH of the washing water, and finally the polymer collected by filtration was vacuum dried to obtain sulfonated SEBS.
  • the sulfonation rate of the benzene ring of the styrene unit of the obtained sulfonated SEBS was 36.1 mol% from 1 H-NMR analysis, and the ion exchange capacity was 0.96 meq / g.
  • Reference Example 5 Synthesis of Sulfonated SEBS A sulfonating reagent was prepared by reacting 18.9 ml of acetic anhydride and 8.5 ml of sulfuric acid at 0 ° C. in 37.8 ml of methylene chloride. On the other hand, 100 g of SEBS obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen. I let you. After dissolution, the sulfonation reagent was gradually added dropwise over 5 minutes. After stirring at 35 ° C. for 2 hours, the polymer solution was poured into 2 L of distilled water while stirring to coagulate and precipitate the polymer.
  • the precipitated solid was washed with distilled water at 90 ° C. for 30 minutes, and then filtered. This washing and filtration operation was repeated until there was no change in the pH of the washing water, and finally the polymer collected by filtration was vacuum dried to obtain sulfonated SEBS.
  • the sulfonation rate of the benzene ring of the styrene unit of the obtained sulfonated SEBS was 17.8 mol% from 1 H-NMR analysis, and the ion exchange capacity was 0.49 meq / g.
  • the polymer solution was poured into 1 L of distilled water while stirring to coagulate and precipitate the polymer.
  • the precipitated solid was washed with distilled water at 90 ° C. for 30 minutes and then filtered. This washing and filtration operation was repeated until there was no change in the pH of the washing water, and finally the polymer collected by filtration was vacuum dried to obtain sulfonated tBSSEPStBS.
  • the 4-tert-butylstyrene unit of the resulting sulfonated tBSSEPStBS was not sulfonated, and only the styrene unit was sulfonated.
  • the sulfonation rate of the benzene ring in the styrene unit was 100 mol% from 1 H-NMR analysis, and the ion exchange capacity was 0.97 meq / g.
  • the polymer solution was poured into 1 L of distilled water while stirring to coagulate and precipitate the polymer.
  • the precipitated solid was washed with distilled water at 90 ° C. for 30 minutes and then filtered. This washing and filtration operation was repeated until there was no change in the pH of the washing water, and finally the polymer collected by filtration was vacuum dried to obtain sulfonated tBSSEPStBS.
  • the 4-tert-butylstyrene unit of the resulting sulfonated tBSSEPStBS was not sulfonated, and only the styrene unit was sulfonated.
  • the sulfonation rate of the benzene ring in the styrene unit was 100 mol% from 1 H-NMR analysis, and the ion exchange capacity was 1.94 meq / g.
  • Reference Example 8 Synthesis of Sulfonated tBSSEPStBS 100 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 3 was vacuum-dried for 1 hour in a glass reaction vessel equipped with a stirrer, and after nitrogen substitution, 956 ml of methylene chloride was added, The mixture was stirred at 35 ° C. for 2 hours for dissolution. After dissolution, the sulfonating reagent obtained by reacting 16.1 ml of acetic anhydride and 7.2 ml of sulfuric acid at 0 ° C. in 32.1 ml of methylene chloride was gradually added dropwise over 5 minutes. After stirring at 35 ° C.
  • the polymer solution was poured into 1 L of distilled water while stirring to coagulate and precipitate the polymer.
  • the precipitated solid was washed with distilled water at 90 ° C. for 30 minutes and then filtered. This washing and filtration operation was repeated until there was no change in the pH of the washing water, and finally the polymer collected by filtration was vacuum dried to obtain sulfonated tBSSEPStBS.
  • the 4-tert-butylstyrene unit of the resulting sulfonated tBSSEPStBS was not sulfonated, and only the styrene unit was sulfonated.
  • the sulfonation rate of the benzene ring in the styrene unit was 19.0 mol% from 1 H-NMR analysis, and the ion exchange capacity was 0.42 meq / g.
  • Embodiment 1 of the present invention including each of the above reference examples, the ion exchange capacity was measured by the following method. Using the block copolymer obtained in each reference example as a sample, the sample was weighed (a (g)) in a glass container that can be sealed, and an excess amount of a saturated aqueous sodium chloride solution was added thereto and stirred overnight. . Hydrogen chloride generated in the system was titrated (b (ml)) with a 0.01N NaOH standard aqueous solution (titer f) using a phenolphthalein solution as an indicator. The ion exchange capacity was determined by the following formula.
  • Reference Example 9 Preparation of metal phosphate SnO 2 manufactured by Wako Pure Chemical Industries, Al (OH) 3 manufactured by Wako Pure Chemical Industries, H 3 PO 4 manufactured by Wako Pure Chemical Industries, Ltd. and pure water are mixed in a beaker and heated to about 300 ° C. until a paste is formed. And stirred with a stirrer. The obtained paste was transferred to an alumina square sheath and subjected to a solid phase reaction at 650 ° C. for 2.5 hours in an electric furnace. Thereafter, the obtained calcined body was pulverized with a mortar and pestle to obtain Sn 0.95 Al 0.05 P 2 O 7 powder.
  • the charge ratio of SnO 2 and Al (OH) 3 is 95: 5, and the charge amount of H 3 PO 4 is determined by quantifying cation species and phosphorus by fluorescent X-ray diffraction (XRF).
  • XRF fluorescent X-ray diffraction
  • tBSStBS poly (4-tert-butylstyrene) -b-polystyrene-b-poly (4-tert-butylstyrene)
  • the number average molecular weight (GPC measurement, polystyrene conversion) of the obtained tBSStBS was 72000
  • the content of styrene units determined from 1 H-NMR measurement was 49% by mass
  • the content of 4-tert-butylstyrene units was 51 It was mass%.
  • Reference Example 11 Synthesis of Sulfonated tBSStBS 100 g of the block copolymer (tBSStBS) obtained in Reference Example 10 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour, and then purged with nitrogen, after which 953 ml of methylene chloride was added, The mixture was stirred at 35 ° C. for 2 hours for dissolution. After dissolution, a sulfonating reagent obtained by reacting 29.3 ml of acetic anhydride and 13.1 ml of sulfuric acid at 0 ° C. in 58.5 ml of methylene chloride was gradually added dropwise over 5 minutes. After stirring at 35 ° C.
  • the polymer solution was poured into 1 L of distilled water while stirring to coagulate and precipitate the polymer.
  • the precipitated solid was washed with distilled water at 90 ° C. for 30 minutes and then filtered. This washing and filtration operation was repeated until there was no change in the pH of the washing water, and the polymer collected at the end was vacuum dried to obtain sulfonated tBSStBS.
  • the 4-tert-butylstyrene unit of the obtained sulfonated tBSStBS was not sulfonated, and only the styrene unit was sulfonated.
  • the sulfonation rate of the benzene ring in the styrene unit was 50.0 mol% from 1 H-NMR analysis, and the ion exchange capacity was 1.99 meq / g.
  • the polymer collected by filtration was vacuum dried to obtain S-PEEK.
  • the sulfonation rate of the obtained S-PEEK was 65.0 mol% from 1 H-NMR analysis, and the ion exchange capacity was 1.83 meq / g.
  • IEC ion exchange capacity
  • the sulfonated SEBS / metal phosphate mixed solution was released onto a PET film [Toyobo Ester Film K1504] manufactured by Toyobo Co., Ltd.].
  • the film was coated with a thickness of about 350 ⁇ m, sufficiently dried at room temperature, and then sufficiently dried under vacuum to obtain a film having a thickness of 40 ⁇ m.
  • the median diameter of the metal phosphate was 3.44 ⁇ m, and the mode diameter was 1.36 ⁇ m.
  • Example 1-2 Preparation of sulfonated SEBS / metal phosphate mixed solution and preparation of composite membrane
  • the mass ratio of sulfonated SEBS (IEC 0.96 meq / g) obtained in Reference Example 4 to metal phosphate was 50/50.
  • a film having a thickness of 35 ⁇ m was obtained in the same manner as in Example 1-1 except that.
  • the median diameter of the metal phosphate was 3.53 ⁇ m, and the mode diameter was 1.38 ⁇ m.
  • the median diameter of the metal phosphate was 3.24 ⁇ m, and the mode diameter was 1.32 ⁇ m.
  • Example 1-4 Preparation of sulfonated tBSSEPStBS / metal phosphate mixed solution and preparation of composite membrane 14% by mass of toluene / isobutyl alcohol (mass ratio 8 / 2) A solution was prepared, and the metal phosphate obtained in Reference Example 9 was added to this solution so that the mass ratio of sulfonated tBSSEPStBS / metal phosphate was 90/10.
  • the obtained sulfonated tBSSEPStBS / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.
  • the sulfonated SEBS / metal phosphate mixture was coated on the Toyobo Ester Film K1504 to a thickness of about 350 ⁇ m and sufficiently dried at room temperature. By sufficiently vacuum drying, a film having a thickness of 32 ⁇ m was obtained.
  • the median diameter of the metal phosphate was 3.38 ⁇ m, and the mode diameter was 1.32 ⁇ m.
  • the median diameter of the metal phosphate was 3.34 ⁇ m, and the mode diameter was 1.32 ⁇ m.
  • the median diameter of the metal phosphate was 3.36 ⁇ m, and the mode diameter was 1.32 ⁇ m.
  • a film having a thickness of 38 ⁇ m was obtained by the same operation as in Example 1-1.
  • the median diameter of the metal phosphate was 3.28 ⁇ m, and the mode diameter was 1.33 ⁇ m.
  • the median diameter of the metal phosphate was 3.26 ⁇ m, and the mode diameter was 1.27 ⁇ m.
  • the sulfonated SEBS / metal phosphate mixture was coated on the Toyobo Ester Film K1504 to a thickness of about 350 ⁇ m and sufficiently dried at room temperature. By sufficiently vacuum drying, a film having a thickness of 34 ⁇ m was obtained.
  • the median diameter of the metal phosphate was 3.24 ⁇ m, and the mode diameter was 1.31 ⁇ m.
  • the median diameter of the metal phosphate was 3.25 ⁇ m, and the mode diameter was 1.24 ⁇ m.
  • Example 1-11 Preparation of sulfonated tBSSEPStBS / metal phosphate mixed solution and preparation of composite membrane 16% by mass of toluene / isobutyl alcohol (mass ratio 8 / 2) A solution was prepared, and the metal phosphate obtained in Reference Example 9 was added to this solution so that the mass ratio of sulfonated tBSSEPStBS / metal phosphate was 90/10.
  • the obtained sulfonated tBSSEPStBS / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.
  • the sulfonated SEBS / metal phosphate mixture was coated on the Toyobo Ester Film K1504 to a thickness of about 350 ⁇ m and sufficiently dried at room temperature. By sufficiently vacuum drying, a film having a thickness of 34 ⁇ m was obtained.
  • the median diameter of the metal phosphate was 3.42 ⁇ m and the mode diameter was 1.31 ⁇ m.
  • Comparative Example 1-1 Preparation of PTFE / Metal Phosphate Composite Membrane and Preparation of Composite Membrane Metal phosphate obtained in Reference Example 9 and PTFE (polytetrafluoroethylene) powder (Mitsui DuPont Fluorochemical Co., Ltd., Teflon 6- J) is kneaded well with a mortar at a ratio of PTFE powder / metal phosphate of 90/10 until it becomes a lump, and rolled using a roller stretcher to obtain a film having a thickness of 30 ⁇ m. It was.
  • PTFE polytetrafluoroethylene
  • Comparative Example 1-2 Preparation of PTFE / metal phosphate composite membrane and preparation of composite membrane A 30 ⁇ m-thickness was prepared in the same manner as in Comparative Example 1-1 except that the mass ratio of PTFE powder / metal phosphate was 50/50. A membrane was obtained.
  • Comparative Example 1-3 Preparation of PTFE / metal phosphate composite membrane, and preparation of composite membrane A 30 ⁇ m-thickness was prepared by the same operation as in Comparative Example 1-1 except that the mass ratio of PTFE powder / metal phosphate was 30/70. A membrane was obtained.
  • Comparative Example 1-4 Preparation of SEBS / metal phosphate composite membrane and preparation of composite membrane A 10% by weight toluene / isobutyl alcohol (mass ratio 8/2) solution of SEBS obtained in Reference Example 1 was prepared. The metal phosphate obtained in 9 was added so that the mass ratio of SEBS / metal phosphate was 30/70. The above-mentioned SEBS / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.
  • the SEBS / metal phosphate mixed solution was coated on the Toyobo Ester Film K1504 with a thickness of about 350 ⁇ m, and sufficiently dried at room temperature. A film having a thickness of 42 ⁇ m was obtained by vacuum drying.
  • the median diameter of the metal phosphate was 3.68 ⁇ m, and the mode diameter was 1.44 ⁇ m.
  • a tBS SEPStBS / metal phosphate mixed solution was coated on a Toyobo Ester film K1504 with a thickness of about 350 ⁇ m and sufficiently dried at room temperature.
  • a film having a thickness of 35 ⁇ m was obtained by vacuum drying.
  • the median diameter of the metal phosphate was 3.53 ⁇ m, and the mode diameter was 1.41 ⁇ m.
  • Comparative Example 1-12 Preparation of sulfonated tBSStBS / metal phosphate mixed solution and production of composite membrane Prepared 15% by weight toluene / isobutyl alcohol (mass ratio 7/3) solution of sulfonated tBSStBS obtained in Reference Example 11. To this solution, the metal phosphate obtained in Reference Example 9 was added so that the mass ratio of sulfonated tBSStBS / metal phosphate was 30/70. The obtained sulfonated tBSStBS / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.
  • a sulfonated tBSStBS / metal phosphate mixed solution was coated on Toyobo Ester Film K1504 at a thickness of about 200 ⁇ m and sufficiently dried at room temperature. By sufficiently vacuum drying, a film having a thickness of 38 ⁇ m was obtained.
  • the produced sulfonated tBSStBS / metal phosphate composite membrane had such a low membrane strength that it was broken when peeled off from the substrate. Since peeling from the substrate was impossible, an electrode was placed on the surface opposite to the substrate while the substrate was attached, and the ionic conductivity was measured by the AC impedance method.
  • the median diameter of the metal phosphate was 3.62 ⁇ m and the mode diameter was 1.55 ⁇ m.
  • Comparative Example 1-13 Preparation of Sulfonated tBSStBS / Metal Phosphate-PTFE Composite Membrane
  • Comparative Example 1-14 Preparation of S-PEEK / metal phosphate mixed solution and preparation of composite membrane A 20% by mass dimethyl sulfoxide solution of S-PEEK obtained in Reference Example 12 was prepared, and this solution was obtained in Reference Example 9. The metal phosphate was added so that the mass ratio of S-PEEK / metal phosphate was 30/70. The obtained S-PEEK / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.
  • the S-PEEK / metal phosphate mixed solution was coated on Toyobo Ester Film K1504 at a thickness of about 200 ⁇ m and sufficiently dried at 100 ° C. Thereafter, the film was sufficiently vacuum-dried to obtain a film having a thickness of 60 ⁇ m.
  • the produced S-PEEL / metal phosphate composite film had such a low film strength that it was broken when peeled off from the substrate. Since peeling from the substrate was impossible, an electrode was placed on the surface opposite to the substrate while the substrate was attached, and the ionic conductivity was measured by the AC impedance method.
  • the median diameter of the metal phosphate was 5.51 ⁇ m, and the mode diameter was 6.28 ⁇ m.
  • Comparative Example 1-15 Preparation of S-PEEK / Metal Phosphate-PTFE Composite Membrane S-PEEK / Metal Phosphate Composite Electrolyte obtained in Comparative Example 1-14 and PTFE (Teflon 6-J manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) Film formation was attempted by rolling after kneading in a mortar. A film with a thickness of 2 mm was obtained by setting the mass% of PTFE to 58%.
  • Electrolyte Membranes of Examples 1-1 to 1-11 and Comparative Examples 1-1 to 1-11 as an Electrolyte Membrane for a Polymer Electrolyte Fuel Cell In the following test, a sample of the aspect 1 of the present invention was used. The electrolyte membrane obtained in each example or comparative example was used.
  • An electrode for a polymer electrolyte fuel cell was produced by the following procedure. A 5% by mass methanol solution of Nafion was added to and mixed with the Pt—Ru alloy catalyst-supporting carbon so that the mass ratio of the Pt—Ru alloy to Nafion was 2: 1 to prepare a uniformly dispersed paste. This paste was applied to a transfer sheet and dried for 24 hours to prepare an anode side catalyst sheet. Also, a 5% by mass solution of Nafion in a mixed solvent of lower alcohol and water was added to and mixed with Pt catalyst-supported carbon so that the mass ratio of Pt catalyst to Nafion was 2: 1, and dispersed uniformly.
  • the prepared paste was prepared, and a cathode side catalyst sheet was prepared in the same manner as the anode side.
  • the electrolyte membrane produced in the first aspect of the present invention is sandwiched between the two types of catalyst sheets so that the membrane and the catalyst surface face each other, and the outside is sandwiched between two heat resistant films and two stainless steel plates in order.
  • the membrane and the catalyst sheet were joined by hot pressing (130 ° C., 1.5 MPa, 8 min). Finally, the stainless steel plate and the heat resistant film were removed, and the transfer sheet was peeled off to produce a membrane-electrode assembly.
  • the membrane-electrode assembly produced is sandwiched between two carbon papers, the outside is sandwiched between two conductive separators that also serve as gas supply channels, and the outside is further joined to two current collector plates.
  • an evaluation cell for a polymer electrolyte fuel cell was produced by sandwiching the two clamp plates.
  • Table 1 shows the degrees.
  • Table 2 shows the ionic conductivity of the films produced in Examples 1-1 and 1-2 and Comparative Example 1-8 at 40 ° C. and a relative humidity of 30 to 90%.
  • FIG. 2 show the results of a fuel cell power generation performance test using hydrogen at a relative humidity of 30%.
  • Methanol permeation rate ( ⁇ mol / cm 2 min for the membranes prepared in Examples 1-2, 1-4 to 1-9 and 1-11 and Comparative Examples 1-1 to 1-6 and 1-8 to 1-10
  • Table 5 A fuel cell power generation performance test using a 3M methanol aqueous solution at a cell temperature of 40 ° C.
  • Example 1-10 for a single cell for a polymer electrolyte fuel cell produced using the membranes produced in Example 1-10 and Comparative Example 1-9.
  • the results are shown in Table 6 and FIG.
  • the ionic conductivity of the films prepared in Examples 1-8 and 1-10 at 65 ° C. and a relative humidity of 30 to 90% is 65 ° C. and relative humidity 30 of the film prepared in Comparative Examples 1-12 to 1-15.
  • Table 7 and FIG. 4 show the ionic conductivity at ⁇ 90%.
  • the cell resistance at 1.25 A was measured, and the MCO at 5 A was measured.
  • Example 1-11 and Comparative Example 1-10 10% by mass of metal phosphate was combined to form an electrolyte membrane. It was confirmed that the ionic conductivity was improved. Further, from comparison between Examples 1-1 and 1-2 and Comparative Example 1-6, Examples 1-4 to 1-6 and Comparative Example 1-8, Example 1-9 and Comparative Example 1-9, It was found that when the block copolymer has a large number of ion conductive groups, the ionic conductivity in water does not tend to increase or decrease significantly.
  • PTFE (Comparative Examples 1-1 to 1-3), which is conventionally suitable as a binder, contains 70% by mass or more of metal phosphate in order to develop an ionic conductivity of 0.01 S / cm or more. It was necessary to add. In addition, when a copolymer having no ion conductive group was used, the same tendency as PTFE was observed (Comparative Examples 1-4 and 1-5).
  • the membrane-electrode assembly using the electrolyte membrane obtained by using the electrolyte according to aspect 1 of the present invention did not show any peeling or the like, and had excellent bondability. It became clear that.
  • Example 1-2 and Comparative Example 1-6 In comparison with Comparative Example 1-10, no significant increase in methanol permeation rate (MCO) was observed due to complexation with metal phosphate.
  • MCO methanol permeation rate
  • Example 1-2 and Comparative Example 1-6 in Table 2 In addition, the comparison between Example 1-2 and Comparative Example 1-6 in Table 2, and the comparison between Examples 1-7 and 1-8 and Comparative Example 1-8 in Table 3, Since the ionic conductivity under low humidity conditions is improved by the composite, the electrolyte of aspect 1 of the present invention improves the ionic conductivity under low humidity conditions while maintaining the same MCO value. It was found that it can be made.
  • Comparative Examples 1-1 and 1-2 using PTFE which is considered to be suitable as a conventional binder
  • the MCO value was large (Table 5) despite the low ionic conductivity (Table 1). ).
  • Comparative Example 1-1 although the MCO value is small (Table 5), the ionic conductivity is remarkably lower than those of Example 1-11 and Comparative Example 1-10, which have comparable MCO values (Table 1). ), Does not exhibit sufficient function as an electrolyte membrane.
  • SEBS and tBSSEPEtBS (Comparative Examples 1-4 and 1-5) having no ion conductive group showed the same tendency (Tables 1 and 5), but formed a dense electrolyte membrane as compared with PTFE.
  • the MCO was low even when the metal phosphate had the same mass ratio (Comparison between Comparative Examples 1-4 and 1-5 and Comparative Example 1-3 in Table 5).
  • the copolymer has an ion conductive group, so that Since an interaction such as hydrogen bonding is expressed between the phosphate group and the ion conductive group of the copolymer, a denser electrolyte membrane can be formed and the MCO is reduced (Table 5). From the above description, it is clear that the electrolyte membrane of aspect 1 of the present invention can achieve both high ionic conductivity under low humidity conditions and MCO suppression.
  • the electrolyte membrane obtained from the electrolyte of aspect 1 of the present invention maintains the cell resistance at the same time during DMFC power generation, It is clear that the maximum power density can be improved.
  • MCO reduction the metal phosphate in the electrolyte membrane is also responsible for proton conduction, so the electroosmosis phenomenon that occurs when proton conduction through water occurs in conventional polymer electrolyte membranes can be suppressed. It is understood that this is an effect obtained by reducing the amount of methanol dragged by the moving water.
  • the increase in the maximum power density is attributed to the suppression of the above-described electroosmosis phenomenon, which suppresses the flooding phenomenon that inhibits the oxygen diffusion of the cathode and consequently reduces the output. It is understood. Further, when the single cell after the power generation test was disassembled, the membrane-electrode assembly using the electrolyte membrane obtained by using the electrolyte of aspect 1 of the present invention did not show any peeling and excellent bonding properties. It became clear that.
  • Example 1-8 In Table 7, from the comparison between Example 1-8 and Comparative Examples 1-12 and 1-14, when the mass ratio of the metal phosphate was the same, although the ion exchange capacity of the polymer was low, It was confirmed that the composite membrane of Example 1-8 had high ionic conductivity under low humidity conditions. Further, from the comparison between Example 1-10 and Comparative Examples 1-12 and 1-14, when the ion exchange capacity of the polymer was the same, it was wide although the mass% of the metal phosphate was low. It was confirmed that the ionic conductivity of the composite membrane of Example 1-10 was high in the humidity range.
  • Example 2-1 Preparation of sulfonated SEBS / metal phosphate mixed solution and preparation of composite membrane-1
  • a 10% by mass toluene / isobutyl alcohol (mass ratio 8/2) solution of the sulfonated SEBS (ion exchange capacity 0.96 meq / g) obtained in Reference Example 4 was prepared, and this solution was obtained in Reference Example 9.
  • the resulting metal phosphate was added so that the mass ratio of sulfonated SEBS / metal phosphate was 10/90.
  • the above sulfonated SEBS / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer, and subjected to ultrasonic treatment for 30 minutes.
  • the sulfonated SEBS / metal phosphate mixed solution was subjected to a release-treated PET film ["Toyobo Ester Film K1504" manufactured by Toyobo Co., Ltd .; The film was obtained by sufficiently drying at room temperature and then vacuum drying.
  • particle size measurement particle size measurement by static light scattering, LA-950 manufactured by HORIBA; the same applies hereinafter
  • the median diameter of the metal phosphate was 3.44 ⁇ m and the mode diameter was 1.36 ⁇ m.
  • Example 2-2 Preparation of sulfonated SEBS / metal phosphate mixed solution and preparation of composite membrane-2 A membrane was obtained in the same manner as in Example 2-1, except that the mass ratio of sulfonated SEBS / metal phosphate was 20/80. As a result of the particle size measurement, the median diameter of the metal phosphate was 3.53 ⁇ m, and the mode diameter was 1.38 ⁇ m.
  • Example 2-3 Preparation of sulfonated SEBS / metal phosphate mixed solution and preparation of composite membrane-3 A membrane was obtained in the same manner as in Example 2-1, except that the mass ratio of sulfonated SEBS / metal phosphate was 30/70. As a result of the particle size measurement, the median diameter of the metal phosphate was 3.24 ⁇ m, and the mode diameter was 1.32 ⁇ m.
  • Example 2-4 Preparation of sulfonated SEBS / metal phosphate mixed solution and preparation of composite membrane-4 A membrane was obtained in the same manner as in Example 2-1, except that the mass ratio of sulfonated SEBS / metal phosphate was 50/50. As a result of the particle size measurement, the median diameter of the metal phosphate was 3.26 ⁇ m, and the mode diameter was 1.27 ⁇ m.
  • Example 2-5 Preparation of sulfonated SEBS / metal phosphate mixed solution and preparation of composite membrane-5 A membrane was obtained in the same manner as in Example 2-1, except that the mass ratio of sulfonated SEBS / metal phosphate was 75/25. As a result of the particle size measurement, the median diameter of the metal phosphate was 3.38 ⁇ m, and the mode diameter was 1.32 ⁇ m.
  • Comparative Example 2-1 Preparation of PTFE / metal phosphate composite membrane-1
  • the metal phosphate obtained in Reference Example 9 and PTFE powder (manufactured by Mitsui DuPont Fluorochemical Co., Ltd., Teflon 6-J) were used at a ratio where the mass ratio of PTFE powder / metal phosphate was 10/90. It knead
  • Comparative Example 2-2 Preparation of PTFE / metal phosphate composite membrane-2
  • a membrane was obtained in the same manner as in Comparative Example 2-1, except that the mass ratio of PTFE powder / metal phosphate was 20/80.
  • Comparative Example 2-3 Preparation of PTFE / metal phosphate composite membrane-3 A membrane was obtained in the same manner as in Comparative Example 2-1, except that the mass ratio of PTFE powder / metal phosphate was 30/70.
  • Comparative Example 2-4 Preparation of PTFE / metal phosphate composite membrane -4 A membrane was obtained in the same manner as in Comparative Example 2-1, except that the mass ratio of PTFE powder / metal phosphate was 50/50.
  • Comparative Example 2-5 Preparation of PTFE / metal phosphate composite membrane-5 A membrane was obtained in the same manner as in Comparative Example 2-1, except that the mass ratio of PTFE powder / metal phosphate was 75/25.
  • Comparative Example 2-6 Preparation of PTFE film PTFE powder was well kneaded into a lump using a mortar and rolled using a roller stretcher to obtain a film.
  • the composite membrane of aspect 2 of the present invention is a polymer block (A) containing an ion conductive group. Since the ion channel formed from the above compensates ionic conduction between the metal phosphates even at 150 ° C. and without humidification, the metal phosphate mass ratio is particularly 70 as compared with the composite membrane using PTFE as a binder. When it was less than%, high ionic conductivity was exhibited. Also from the membrane strength shown in Table 8, it was clarified that the composite electrolyte membrane of aspect 2 of the present invention can achieve both membrane strength and ionic conductivity and is excellent as an electrolyte membrane for fuel cells.
  • the composite electrolyte membrane of aspect 2 of the present invention contains an ion conductive group in addition to excellent membrane strength and excellent moldability. Since ion conduction between metal phosphates can be compensated by ion channels formed from the polymer block (A), pinholes, defects, cracks, etc. do not occur even when the electrolyte membrane thickness is reduced. As a result, the open circuit voltage (OCV) was maintained high even when the film thickness was small. In addition, the film resistance could be reduced by reducing the film thickness.
  • the composite electrolyte membrane of aspect 2 of the present invention is an excellent electrolyte membrane that can maintain a high cell voltage and has low resistance, and the fuel cell using the electrolyte membrane of aspect 2 of the present invention achieves high output. Obviously it can.
  • Example 3-1 Preparation of sulfonated tBSSEPStBS / metal phosphate mixed solution and preparation of composite membrane-1
  • a 14% by mass toluene / isobutyl alcohol (mass ratio 8/2) solution of the sulfonated tBSSEPStBS (IEC (ion exchange capacity) 0.97 meq / g) obtained in Reference Example 6 was prepared.
  • the metal phosphate obtained in 13 was added so that the mass ratio of sulfonated tBSSEPStBS / metal phosphate was 50/50.
  • the sulfonated tBSSEPStBS / metal phosphate mixed solution described above was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes. After stirring with a magnetic stirrer and ultrasonic treatment four times, the sulfonated tBSSEPStBS / metal phosphate mixed solution was subjected to a release-treated PET film [Toyobo Co., Ltd. “Toyobo Ester Film K1504”; The film was coated with a thickness of about 350 ⁇ m, sufficiently dried at room temperature, and then sufficiently dried under vacuum to obtain a film with a thickness of 30 ⁇ m.
  • the obtained electrolyte membrane was put in toluene / isobutyl alcohol (mass ratio 8/2) to dissolve sulfonated tBSSEPStBS, and particle size measurement by static light scattering (LA-950 made by HORIBA) was performed using the resulting suspension.
  • LA-950 made by HORIBA
  • the median diameter of the metal phosphate was 92 nm
  • the mode diameter was 85 nm.
  • Example 3-2 Preparation of sulfonated tBSSEPStBS / metal phosphate mixed solution and preparation of composite membrane-2
  • a 12% by mass toluene / isobutyl alcohol (mass ratio 7/3) solution of the sulfonated tBSSEPStBS (IEC 1.94 meq / g) obtained in Reference Example 7 was prepared, and this solution was obtained in Reference Example 13.
  • the metal phosphate was added so that the mass ratio of sulfonated tBSSEPStBS / metal phosphate was 50/50.
  • the sulfonated tBSSEPStBS / metal phosphate mixed solution described above was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.
  • a sulfonated tBSSEPStBS / metal phosphate mixed solution was coated on a release-treated PET film with a thickness of about 350 ⁇ m and allowed to dry sufficiently at room temperature. Thereafter, the film was sufficiently vacuum-dried to obtain a film having a thickness of 34 ⁇ m.
  • the obtained electrolyte membrane was put in toluene / isobutyl alcohol (mass ratio 7/3) to dissolve sulfonated tBSSEPStBS, and the particle size was measured by static light scattering using the resulting suspension.
  • the median diameter of the phosphate was 71 nm, and the mode diameter was 69 nm.
  • Example 1-12 Preparation of sulfonated tBSSEPStBS / metal phosphate mixed solution and preparation of composite membrane-3 A film having a thickness of 38 ⁇ m was obtained in the same manner as in Example 3-1, except that the metal phosphate obtained in Reference Example 9 was used.
  • the obtained electrolyte membrane was put in toluene / isobutyl alcohol (mass ratio 8/2) to dissolve the sulfonated tBSSEPStBS, and the particle size was measured by static light scattering using the resulting suspension.
  • the median diameter of the phosphate was 3.26 ⁇ m, and the mode diameter was 1.27 ⁇ m.
  • Example 1-13 Preparation of sulfonated tBSSEPStBS / metal phosphate mixed solution and preparation of composite membrane-4 A film having a thickness of 34 ⁇ m was obtained in the same manner as in Example 3-2 except that the metal phosphate obtained in Reference Example 9 was used.
  • the obtained electrolyte membrane was put in toluene / isobutyl alcohol (mass ratio 7/3) to dissolve sulfonated tBSSEPStBS, and the particle size was measured by static light scattering using the resulting suspension.
  • the median diameter of the phosphate was 3.24 ⁇ m, and the mode diameter was 1.31 ⁇ m.
  • Comparative Example 3-2 Film formation of sulfonated tBSSEPStBS-2
  • the film was coated with a thickness, sufficiently dried at room temperature, and then sufficiently vacuum-dried to obtain a film having a thickness of 29 ⁇ m.
  • Comparative Example 3-3 Preparation of Nafion / metal phosphate mixed solution and preparation of composite membrane-1
  • the metal phosphate obtained in Reference Example 9 was added to a dispersion of Nafion manufactured by DuPont so that the mass ratio of Nafion / metal phosphate was 50/50.
  • the obtained Nafion / metal phosphate mixed solution was stirred for 30 minutes using a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes. After stirring with a magnetic stirrer and sonication four times, the Nafion / metal phosphate mixture was coated on a PET film with a thickness of about 350 ⁇ m and sufficiently dried at room temperature.
  • Comparative Example 3-4 Preparation of Nafion / metal phosphate mixed solution and preparation of composite membrane-2 Except for using the metal phosphate obtained in Reference Example 13, an attempt was made to produce a composite film by the same operation as in Comparative Example 3-3, but many cracks occurred and a self-supporting film could not be obtained. .
  • the median diameter of the metal phosphate was 75 nm and the mode diameter was 71 nm.
  • Methanol permeation rate was determined by setting the electrolyte membrane in the center of the H-shaped cell, 55 ml of 3M (mol / liter) aqueous methanol solution in one side of the two spaces, and 55 ml in the other space. was calculated by measuring the amount of methanol diffusing through the electrolyte membrane into the pure water using gas chromatography while stirring at 25 ° C. (area of the electrolyte membrane: 4. 5 cm 2 ).
  • the cell temperature was 65 ° C.
  • the bubbler temperature was set so that the gas phase temperature for both hydrogen and oxygen was 40 ° C.
  • the relative humidity to which the electrolyte membrane was exposed was adjusted to 30%.
  • the test was conducted under the conditions of hydrogen: 250 ml / min and oxygen: 250 ml / min. 6) Performance evaluation of single cell for fuel cell using methanol Single unit for polymer electrolyte fuel cell prepared using electrolyte membrane obtained in Example 3-2, Example 1-13 and Comparative Example 3-2
  • the output performance of the cell was evaluated.
  • a 3M aqueous methanol solution was used as the fuel, and oxygen was used as the oxidant.
  • the test was conducted at a cell temperature of 40 ° C. under the conditions of MeOH: 1.0 ml / min and oxygen: 174 ml / min.
  • Example 3-2 Phosphate elution amount of electrolyte membrane prepared in Example 1-13 is shown in Table 11.
  • Table 12 shows the ionic conductivity of the electrolyte membranes produced in Example 3-2, Example 1-13 and Comparative Example 3-2 at 65 ° C. and a relative humidity of 30 to 90%.
  • Table 13 shows the methanol permeation rate (converted to ⁇ mol / cm 2 min) of the electrolyte membranes prepared in Example 3-2, Example 1-13, and Comparative Example 3-2.
  • Example 14 and FIG. 7 show the results of the fuel cell power generation performance test using hydrogen of A single cell for a polymer electrolyte fuel cell produced using the membranes produced in Example 3-2, Example 1-13 and Comparative Example 3-2, respectively, using a 3M methanol aqueous solution at a cell temperature of 40 ° C.
  • the results of the fuel cell power generation performance test are shown in Table 15 and FIG. In addition, regarding the evaluated fuel cell performance, the cell resistance at 1.25 A was measured, and the MCO at 5 A was measured.
  • Example 11 From the comparison between Example 3-2 and Example 1-13, when the same mass% of metal phosphate was combined, the particle size of the metal phosphate (measured by static light scattering) It was confirmed that the elution amount of phosphoric acid was reduced by reducing the median diameter from 3.24 ⁇ m to 71 nm.
  • the particle size of the metal phosphate is reduced, the area in contact with the ion conductive group site of the block copolymer increases, the composite membrane becomes dense, and the ion conductive group of the metal phosphate and the block copolymer is increased. It is presumed that a hydrogen bond is formed between the phosphoric acid and the phosphoric acid.
  • Example 3-2 From the comparison between Example 3-2, Example 1-13 and Comparative Example 3-2 in Table 12, the effect of improving the ionic conductivity due to the use of the metal phosphate is obtained when the particle size of the metal phosphate is reduced. However, it can be said that the same level is maintained.
  • Example 3-2 From the comparison of Example 3-2 with Example 1-13 and Comparative Example 3-2 in Table 13, it is clear that methanol crossover is reduced by reducing the particle size of the metal phosphate. This is presumably because a hydrogen bond was formed between the ion conductive group of the block copolymer and the metal phosphate, and the composite membrane became dense.
  • Example 3-1 From the comparison between Example 3-1 and Example 1-12 and Comparative Example 3-1 in Table 14, the effect of reducing cell resistance under low humidity conditions is increased by reducing the particle size of the metal phosphate. It is clear that the power density is improved. Further, when the single cell after the power generation test was disassembled, no peeling or the like was observed in the membrane-electrode assembly using the electrolyte membrane obtained by using the electrolyte of aspect 3 of the present invention. It became clear that the bondability was also excellent.
  • Example 3-2 From the comparison between Example 3-2, Example 1-13 and Comparative Example 3-2 in Table 15, by reducing the particle size of the metal phosphate, the methanol resistance during power generation is maintained while maintaining the same cell resistance. It is clear that over (MCO) is reduced and maximum power density is improved.
  • MCO over
  • the reduction in MCO can suppress the electroosmosis phenomenon that occurs when proton conduction through water occurs in conventional polymer electrolyte membranes because the metal phosphate in the electrolyte membrane also carries proton conduction. It is estimated that this is an effect obtained by reducing the amount of methanol dragged by the moving water.
  • the increase in the maximum output density is attributed to the suppression of the above-described electroosmosis phenomenon, which suppresses the flooding phenomenon that inhibits the oxygen diffusion of the cathode and consequently reduces the output. Presumed. Since the above-described effects are further exhibited by reducing the particle size of the metal phosphate, the DMFC power generation performance is improved. Further, when the single cell after the power generation test was disassembled, no peeling or the like was observed in the membrane-electrode assembly using the electrolyte membrane obtained by using the electrolyte of aspect 3 of the present invention. It became clear that it was excellent also in the property.
  • FIG. 7 is a graph showing ionic conductivity of the electrolyte membrane of Embodiment 1 of the present invention under low humidity conditions (Examples 1-7, 1-8, and 1-10, and Comparative Examples 1-8, 1-9, and 1-11) ).
  • FIG. 3 is a diagram showing the current-cell voltage of a single cell for a fuel cell according to aspect 1 of the present invention, using hydrogen adjusted so that the environment to which the membrane-electrode assembly is exposed is 65 ° C. and a relative humidity of 30%. (Examples 1-7 and 1-8, and Comparative Examples 1-8 and 1-11).
  • FIG. 3 is a diagram showing the current-cell voltage of a single cell for a fuel cell according to aspect 1 of the present invention, using hydrogen adjusted so that the environment to which the membrane-electrode assembly is exposed is 65 ° C. and a relative humidity of 30%. (Examples 1-7 and 1-8, and Comparative Examples 1-8 and 1-11).
  • FIG. 10 is a graph showing the current-power density of a single fuel cell according to aspect 1 of the present invention, in which the cell temperature was 40 ° C., a 3M methanol aqueous solution was used as the fuel, and oxygen was used as the oxidant (Examples 1-10 and Comparative Example 1-9).
  • FIG. 4 is a graph showing ionic conductivity of the electrolyte membrane of Embodiment 1 of the present invention at 40 ° C. and a relative humidity of 30 to 90% (Examples 1-8, 1-10, and Comparative Examples 1-12 to 1-15). ).
  • FIG. 5 is a diagram showing the relationship (Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-5 and 2-7).
  • FIG. 5 is a diagram showing the relationship between the open circuit voltage (OCV) and membrane resistance at 150 ° C. and no humidification conditions, and the membrane thickness of the electrolyte membrane of aspect 2 of the present invention (Example 2-2 and Comparative Example 2-2) ).
  • FIG. 6 is a diagram showing cell voltages (Example 3-1, Example 1-12, and Comparative example 3-1).
  • FIG. 7 is a graph showing the current-power density of a single fuel cell according to aspect 3 of the present invention using a 3M methanol aqueous solution as a fuel and oxygen as an oxidant at a cell temperature of 40 ° C. (Example 3-2, Example 1-13 and Comparative Example 3-2).

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Abstract

La présente invention concerne, par exemple, un électrolyte composite organique-inorganique approprié pour la préparation d'une membrane d'électrolyte destinée à être utilisée dans des piles à combustible à polymères solides. Récemment, l'attention s'est portée sur des piles à combustible à polymères solides, en tant que mesure drastique permettant de résoudre les problèmes d'énergie et d'environnement. Pour permettre l'utilisation pratique et la diffusion des piles à combustible, une membrane d'électrolyte présentant une conductivité ionique élevée, même dans des conditions de faible humidité, est nécessaire. En général, l'augmentation de la quantité d'un groupe de conduction ionique est considérée comme étant efficace dans l'amélioration de la conductivité ionique dans des conditions de faible humidité, mais pose un problème ; par exemple, la durabilité mécanique diminue avec l'augmentation de la quantité du groupe de conduction ionique. Ce problème peut être résolu par un électrolyte formé d'une composition comprenant un copolymère à blocs et un phosphate de métal de conduction ionique. Ledit copolymère à blocs comprend des blocs de polymère (A) et (B) qui entraînent une séparation de phase réciproque. Le bloc de polymère (A) contient un groupe de conduction ionique, le bloc de polymère (B) ayant formé une phase flexible, et le groupe de conduction ionique est présent, sensiblement uniquement dans le bloc de polymère (A).
PCT/JP2009/068065 2008-10-24 2009-10-20 Électrolyte composite organique-inorganique, membrane d'électrolyte, ensemble électrode-membrane et pile à combustible Ceased WO2010047329A1 (fr)

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JP2012079415A (ja) * 2010-09-30 2012-04-19 Toyobo Co Ltd 高分子電解質膜、およびそれを用いた膜／電極接合体，燃料電池
JP2012104244A (ja) * 2010-11-05 2012-05-31 Kuraray Co Ltd 触媒層形成用組成物、ガス拡散電極、膜−電極接合体及び燃料電池
WO2013031634A1 (fr) * 2011-08-31 2013-03-07 株式会社クラレ Copolymère séquencé, membrane électrolytique de type polymère, ensemble membrane-électrode, et pile à combustible à polymère solide
JP2019102330A (ja) * 2017-12-05 2019-06-24 旭化成株式会社 高分子電解質膜、膜電極接合体、及び固体高分子型燃料電池
EP3644420A1 (fr) 2018-10-24 2020-04-29 Toyota Jidosha Kabushiki Kaisha Film conducteur de protons ayant une structure réticulée et pile à combustible

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WO2007094185A1 (fr) * 2006-02-13 2007-08-23 Kuraray Co., Ltd. film polyélectrolytIQUe, ensemble FILM-électrode, et pile à combustible de type polymère solide
WO2008096743A1 (fr) * 2007-02-08 2008-08-14 Sumitomo Chemical Company, Limited Composition conductrice d'ions, film conducteur d'ions la contenant, matériau de catalyseur d'électrode et pile à combustible

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JP2005317238A (ja) * 2004-04-27 2005-11-10 Hitachi Ltd 固体高分子形燃料電池、ハイブリッド膜及び膜／電極接合体
WO2007094185A1 (fr) * 2006-02-13 2007-08-23 Kuraray Co., Ltd. film polyélectrolytIQUe, ensemble FILM-électrode, et pile à combustible de type polymère solide
WO2008096743A1 (fr) * 2007-02-08 2008-08-14 Sumitomo Chemical Company, Limited Composition conductrice d'ions, film conducteur d'ions la contenant, matériau de catalyseur d'électrode et pile à combustible

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012079415A (ja) * 2010-09-30 2012-04-19 Toyobo Co Ltd 高分子電解質膜、およびそれを用いた膜／電極接合体，燃料電池
JP2012104244A (ja) * 2010-11-05 2012-05-31 Kuraray Co Ltd 触媒層形成用組成物、ガス拡散電極、膜−電極接合体及び燃料電池
WO2013031634A1 (fr) * 2011-08-31 2013-03-07 株式会社クラレ Copolymère séquencé, membrane électrolytique de type polymère, ensemble membrane-électrode, et pile à combustible à polymère solide
JPWO2013031634A1 (ja) * 2011-08-31 2015-03-23 株式会社クラレ ブロック共重合体、高分子電解質膜、膜−電極接合体及び固体高分子型燃料電池
JP2019102330A (ja) * 2017-12-05 2019-06-24 旭化成株式会社 高分子電解質膜、膜電極接合体、及び固体高分子型燃料電池
EP3644420A1 (fr) 2018-10-24 2020-04-29 Toyota Jidosha Kabushiki Kaisha Film conducteur de protons ayant une structure réticulée et pile à combustible
CN111092250A (zh) * 2018-10-24 2020-05-01 丰田自动车株式会社 具有桥接结构的质子传导膜和燃料电池
US11322764B2 (en) 2018-10-24 2022-05-03 Toyota Jidosha Kabushiki Kaisha Proton conducting film having crosslinked structure and fuel cell
CN111092250B (zh) * 2018-10-24 2023-04-07 丰田自动车株式会社 具有桥接结构的质子传导膜和燃料电池

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