JP2007048471A - Reinforced electrolyte membrane for fuel cell, manufacturing method of the same, and membrane-electrode assembly for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer fuel cell restraining cross-leak which deteriorates a membrane, caused by reaction heat of hydrogen and oxygen generated at a part just passed through an electrolyte membrane, having high output and excellent durability. <P>SOLUTION: The electrolyte membrane 3 for fuel cell is reinforced by a porous thin film 5, and fine particle of noble metal 4 is coated and/or deposited on a surface and/or in fine pores of the porous film. Manufacturing method of the same and the membrane-electrode assembly for a furl cell are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reinforced electrolyte membrane used for a fuel cell, a method for producing the same, a membrane-electrode assembly for a fuel cell, and a polymer electrolyte fuel cell including the same.

  Fuel cells that generate electricity through the electrochemical reaction of gas have high power generation efficiency, and the exhausted gas is clean and has very little impact on the environment. Applications are expected. Fuel cells can be classified according to their electrolytes. For example, phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, solid polymer fuel cells, and the like are known.

  In particular, the polymer electrolyte fuel cell can be operated at a low temperature of about 80 ° C., and therefore it is relatively easy to handle and has a very high output density compared to other types of fuel cells. Therefore, its use is expected. A polymer electrolyte fuel cell is usually a membrane-electrode assembly (MEA: Membrane-Electrode Assembly) in which a proton conductive polymer membrane is used as an electrolyte, and a pair of electrodes serving as a fuel electrode and an oxygen electrode are provided on both sides thereof. ) Is the power generation unit. Then, a fuel gas such as hydrogen or hydrocarbon is supplied to the fuel electrode, and an oxidant gas such as oxygen or air is supplied to the oxygen electrode, and an electrochemical reaction proceeds at the three-phase interface between the gas, the electrolyte, and the electrode. The electricity is taken out by this.

  A polymer electrolyte fuel cell is composed of a laminate of a membrane-electrode assembly and a separator. The membrane-electrode assembly includes an electrolyte membrane composed of an ion exchange membrane, an electrode composed of a catalyst layer disposed on one surface of the electrolyte membrane (anode, fuel electrode), and an electrode composed of a catalyst layer disposed on the other surface of the electrolyte membrane. (Cathode, air electrode). Between the membrane-electrode assembly and the separator, diffusion layers are provided on the anode side and the cathode side, respectively. In the separator, a fuel gas passage for supplying fuel gas (hydrogen) to the anode is formed, and an oxidizing gas passage for supplying oxidizing gas (oxygen, usually air) to the cathode. The separator is also formed with a refrigerant flow path for flowing a refrigerant (usually cooling water). A cell is formed by stacking a membrane-electrode assembly and a separator, a module is formed from at least one cell, a module is stacked to form a cell stack, and terminals, insulators, end plates are formed at both ends of the cell stack in the cell stacking direction. The cell stack is clamped in the cell stacking direction, and is fixed with a fastening member and a bolt and a nut extending in the cell stacking direction outside the cell stacking body to constitute a stack.

On the fuel electrode (anode) side of each cell, hydrogen is converted into hydrogen ions (protons) and electrons, and the hydrogen ions move through the electrolyte membrane to the cathode side, and oxygen, hydrogen ions, and electrons on the cathode side. (Electrons generated at the fuel electrode of the adjacent MEA come through the separator, or electrons generated at the fuel electrode of the cell at one end of the cell stacking direction pass through the external circuit to the air electrode (cathode) of the other cell). The next reaction to produce takes place.
Anode side: H ₂ → 2H ⁺ + 2e ⁻
Cathode side: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O

  The electrolyte membrane should move only protons through the membrane in the film thickness direction, but a small amount of hydrogen from the fuel electrode (anode) side to the air electrode (cathode) side, or a small amount of air from the air electrode (cathode). The film may move in the film thickness direction from the side to the fuel electrode (anode) side (this is called cross leak).

  As described above, in the polymer electrolyte fuel cell, a part of each gas supplied to both electrodes diffuses inside the electrolyte without contributing to the electrochemical reaction, and is supplied to the electrode on the counter electrode. There is a so-called cross leak problem of mixing with the generated gas. When the cross leak occurs, the battery voltage decreases and the energy efficiency decreases. Furthermore, there is a possibility that the polymer membrane as an electrolyte has a hole due to a combustion reaction due to cross leak, and the battery cannot be operated.

  On the other hand, from the viewpoint of reducing the internal resistance of the battery and increasing the output, it has been studied to reduce the thickness of the polymer film that is an electrolyte. However, if the polymer film is thinned, the gas easily diffuses, so the problem of the cross leak becomes more serious. In addition to the reduction in the mechanical strength of the polymer film itself due to the reduction in thickness, pinholes and the like are likely to occur during the production of the polymer film. These defects in the polymer film itself are one of the causes of increased cross leak.

  Accordingly, various studies have been made to suppress cross leaks. For example, Patent Document 1 below discloses an attempt to suppress the cross leak by shifting the positions of pinholes generated in each polymer film by laminating a plurality of polymer films used as an electrolyte. From the viewpoint of reinforcing the polymer film itself, for example, Patent Document 2 below discloses a polymer film reinforced with fibers or the like.

  However, a laminate of the above polymer films is merely a stack of several identical polymer films, and is merely an increase in film thickness. That is, since the mechanical strength of the polymer film is not sufficient, it is difficult to suppress the cross leak during long-term use. In addition, the method of reinforcing the polymer film with fibers or the like requires a complicated manufacturing process of the polymer film and costs. Further, although the strength of the polymer film is improved, it cannot be said that suppression of cross leak is sufficient.

  Patent Document 3 listed below provides a membrane-electrode assembly for a fuel cell that is low in cross-leakage and inexpensive, and has a high output and a solid polymer fuel cell that is excellent in durability. A surface modified film in which a plurality of polymer films are laminated as an electrolyte of an electrode assembly, and at least one of the plurality of polymer films is modified on at least one surface thereof The invention is disclosed. Specific examples of the method for modifying the surface of the polymer film include crosslinking treatment, grafting treatment, and plasma treatment. Since at least one of the surfaces of the polymer film used as the electrolyte is modified, the polymer film is strengthened, and the mechanical strength of the polymer film is improved even when the film thickness is thin. When the fuel cell is operated, various stresses such as compression and tension are applied to the electrolyte at a high temperature of about 80 ° C. Even under such conditions, the surface-modified film does not cause defects such as pinholes due to the high mechanical strength of the film. Therefore, the cross leak is sufficiently suppressed. Furthermore, by laminating a plurality of polymer films, it becomes difficult for the gas to diffuse, and cross leak can be further suppressed.

  The method of Patent Document 3 below is a method in which the surface of a polymer film is modified. Since only the surface of the polymer film is modified, not the entire polymer film, the time required for the modification treatment and the amount of reagents used for the treatment may be reduced. That is, there is an advantage that the reforming process can be easily performed at low cost. However, since only the surface of the polymer film is modified, not the entire polymer film, it cannot be said that cross-leakage is sufficiently suppressed.

On the other hand, as one of the prior arts, there is an electrolyte membrane formed by casting using a mixed solution in which Pt fine particles are mixed in an electrolyte dispersion solution. It is expected to have a function of converting cross leaked H ₂ and O ₂ gas into H ₂ O molecules with Pt fine particles, and the generated water is intended to be used as a humidifier for a fuel cell. However, these functions appear only when the permeated H ₂ and O ₂ gas come into contact with the Pt fine particles, and in this configuration, the contact probability between the permeated gas and the Pt fine particles is low. In order to increase the contact probability between the permeated gas and the Pt fine particles, it is necessary to increase the Pt particle diameter or increase the addition amount, which is disadvantageous in terms of cost.

JP-A-6-84528 JP 2001-35508 A JP 2003-272663 A

  The present invention has been made in view of the above-mentioned circumstances, and suppresses cross-leakage that causes hydrogen to react with oxygen and generate heat when it passes through an electrolyte membrane, thereby degrading the membrane, and suppresses short-circuiting due to precious metal deposition. The object is to reduce the durability and life of the fuel cell. It is another object of the present invention to provide a fuel cell membrane-electrode assembly in which cross leak is suppressed. Furthermore, it is an object of the present invention to provide a polymer electrolyte fuel cell having high output and excellent durability by using such a membrane-electrode assembly.

  The present inventor has found that the above-mentioned problems can be solved by using a reinforced electrolyte membrane subjected to specific treatment, and has reached the present invention.

  That is, first, the present invention is an invention of an electrolyte membrane for fuel cells reinforced with a porous thin film, wherein a noble metal is coated and / or deposited on the surface and / or pores of the porous membrane. It is characterized by being.

The reinforced electrolyte membrane for fuel cells of the present invention is roughly classified into the following two types.
(1) The fuel cell electrolyte membrane reinforced with the porous thin film is a fuel cell reinforced electrolyte membrane in which a porous thin film is impregnated with a polymer electrolyte.
(2) The fuel cell electrolyte membrane reinforced with the porous thin film is a fuel cell reinforced electrolyte membrane in which one or more sets of polymer electrolyte membranes and a porous thin film are laminated.

  As the porous thin film used in the reinforced electrolyte membrane for fuel cells of the present invention, the porous thin film preferably has an average pore diameter of 0.1 μm or more, and the porous thin film has a porosity of 40% or more. . As the porous thin film, an organic porous film or an inorganic porous film is applied. Among them, a polytetrafluoroethylene (PTFE) film made porous by a stretching method is preferably exemplified.

  Platinum (Pt) is preferably exemplified as a specific example of the noble metal used in the reinforced electrolyte membrane for fuel cells of the present invention.

2ndly, this invention is invention of the manufacturing method of said reinforced electrolyte membrane for fuel cells, and there exist the following 2 types.
(1) A step of coating and / or depositing a noble metal on the surface and / or pores of the porous film by treating the porous thin film with a compound solution having a noble metal ion species, and coating and / or inclusion of the noble metal And a step of filling the porous thin film with a polymer electrolyte.
(2) a step of coating and / or depositing a noble metal on the surface and / or pores of the porous film by treating the porous thin film with a compound solution having a noble metal ion species, and coating and / or inclusion of the noble metal Including a step of laminating a polymer electrolyte membrane on a porous thin film.

  In the method for producing a reinforced electrolyte membrane for a fuel cell of the present invention, various chemical or physical treatments are employed as a step of coating and / or depositing a noble metal on the surface and / or pores of the porous thin film. The Of these, chemical plating or sputtering is preferably exemplified.

  The average pore diameter, porosity, and specific examples of the porous thin film used in the method for producing a reinforced electrolyte membrane for a fuel cell of the present invention, and specific examples of the noble metal are as described above.

  Thirdly, the present invention provides a pair of electrodes composed of a fuel electrode supplied with a fuel gas and an oxygen electrode supplied with an oxidant gas, and a polymer electrolyte membrane sandwiched between the pair of electrodes, The polymer electrolyte membrane is reinforced with a porous thin film in which a noble metal is coated and / or deposited in the surface and / or pores described above. It is an electrolyte membrane for fuel cells.

  In the membrane-electrode assembly for a fuel cell according to the present invention, the polymer electrolyte membrane may include one or more reinforced electrolyte membranes for the fuel cell.

  Fourthly, the present invention is a polymer electrolyte fuel cell comprising a membrane-electrode assembly having the above-described reinforced electrolyte membrane for fuel cells.

  The electrolyte membrane for a fuel cell reinforced with a porous thin film in which a noble metal is coated and / or deposited in the surface and / or pores of the present invention has a high probability that the gas that has permeated the electrolyte membrane and the noble metal are in contact with each other. The permeated hydrogen reacts with oxygen to generate heat and suppress the cross leak that deteriorates the film, and also suppresses the short circuit due to the precious metal deposition. As a result, the durability and life of the fuel cell can be reduced. In addition, by using a fuel cell membrane-electrode assembly in which cross leakage is suppressed, a solid polymer fuel cell having high output and excellent durability can be obtained.

Hereinafter, the function of the reinforced electrolyte membrane for fuel cells of the present invention will be described with reference to the drawings.
FIG. 1 shows a case in which cross leak occurs and a case in which cross leak occurs but is suppressed by Pt fine particles in the electrolyte membrane. Pt fine particles are dispersed in the electrolyte membrane 3 sandwiched between the anode catalyst layer 1 and the cathode catalyst layer 2. This uses an electrolyte membrane cast by using a mixed liquid in which Pt fine particles are mixed in an electrolyte dispersion solution. This electrolyte membrane reacts with H ₂ and O ₂ gas cross-leaked into Pt fine particles. It is expected to be converted to H ₂ O molecules. However, these functions are not developed until the permeated H ₂ or O ₂ gas comes into contact with the Pt fine particles (region b in FIG. 1: the permeated gas and the Pt fine particles come into contact with each other, and the permeated gas is converted into water. ). In this configuration, the contact probability between the permeated H ₂ and O ₂ gas and the Pt fine particles is low (region a in FIG. 1: the permeate gas does not contact the Pt fine particles and the permeate gas is not converted). To increase the contact probability, it is conceivable to increase the amount of Pt, but this increases the cost.

Further, as in the region b in FIG. 1, when the permeated gas and Pt fine particles come in contact with each other in the electrolyte and the permeated gas is converted into water, and Pt ⁺⁺ ions are reduced and Pt is precipitated, the precipitated Pt There is also a problem that the anode catalyst layer 1 and the cathode catalyst layer 2 are short-circuited.

  FIG. 2 shows a schematic diagram of the principle that cross leak is suppressed when the reinforced electrolyte membrane of the present invention is used. A porous membrane (for example, PTFE porous membrane) 5 in which an electrolyte membrane 3 sandwiched between an anode catalyst layer 1 and a cathode catalyst layer 2 is coated with a film of noble metal such as Pt or fine particles 4 on its surface and / or pores. Is arranged as a reinforcing membrane. The pores are impregnated and filled with an electrolyte resin. Compared with the region b in FIG. 1, Pt fine particles are concentrated and dispersed in the reinforcing film, particularly in the pores.

The major difference from the prior art is that all the permeated H ₂ or O ₂ gas passes through the Pt-coated pores, so there is a high probability that H ₂ and O ₂ gas meet, and the conversion reaction to H ₂ O molecules. The function that is easy to occur is exhibited.

In addition, the following functions are added.
(1) The long ON-OFF Pt ⁺⁺ ions dissolved from the catalyst layer by the generator reduced at the anode side of the H _2, the defect phenomenon causing a short circuit of acicular precipitated cell, the Pt ⁺⁺ ions in the pores Since the diffusion is suppressed and reduction is performed with nearby H ₂ , the Pt deposition site can be concentrated in the vicinity of the porous film. Thereby, it is possible to prevent the cell short circuit of the fuel cell.
(2) The elution Pt precipitates before the short circuit and closes the pores, thereby shutting down and not important.
(3) Since it is an electrolyte membrane for fuel cells reinforced with a porous thin film, the strength of the reinforcing substrate is increased by covering with Pt in addition to exhibiting the strength inherent in the porous membrane, and the dimensions of the electrolyte membrane The rate of change is further reduced.
(4) If the number of reinforcing bases increases, the amount of gas permeation is suppressed, so the amount of Pt used may be smaller than that of the known technique.

  In the present invention, an organic or inorganic porous thin film (pore diameter: 0.1 μm or more, porosity: 40% or more, film thickness: less than the thickness of the electrolyte film) whose surface is coated with Pt by chemical plating or sputtering is used. It is preferable. An electrolyte is impregnated (filled) into the pores of the Pt-coated porous thin film to produce a reinforced electrolyte membrane. There may be any number of Pt-coated porous membranes in the electrolyte membrane. The number of layers can be considered depending on the structure of the porous thin film, but within the range where other film physical properties (for example, ion conductivity) are not deteriorated, the contact probability between the permeated gas and Pt increases even if the Pt coating amount is small if there is a multilayer. Therefore, it is preferable. There is no particular limitation on the electrolyte used.

In the present invention, examples of the configuration of the plating treatment liquid used when the porous film surface is coated with Pt by chemical plating include the following.
(1) Pt ion species (for example, chloroplatinic acid, dinitrodiamine platinum, tetraamminedichloroplatinum, potassium hexahydroxoplatinate, etc.)
(2) Carbon powder (carbon type does not matter. Particle size <1 μm)
(3) Acid electrolyte fine particles (for example, Nafion solution (particle diameter <1 μm))
(4) Surfactant (for example, dimethyl sulfoxide, various alcohols, various surfactants (cationic surfactant, anionic surfactant, nonionic surfactant))
(5) pH adjuster (for example, sodium hydroxide or potassium hydroxide)
(6) Complexing agents (for example, oxycarboxylic acids such as citrate and tartrate, dicarboxylic acids such as malonic acid and maleic acid, salts thereof, amines such as EDTA, triethanolamine, glycine and alanine)
(7) Reducing agent (for example, one of reducing agents usually used in chemical plating such as hypophosphites, human drazine salts, formalin, NaBH ₄ , LiAIH ₆ , dialkylamine borane, sulfite, ascorbate, etc. Use more)

The polymer electrolyte used is preferably a water-repellent electrolyte having, for example, a sulfonyl halide (—SO ₂ F or —SO ₂ Cl) as a side chain terminal group of the electrolyte resin. The EW value serving as an index of the number of side chain terminal groups in the electrolyte is preferably 1500 or less, and more preferably 800 to 1100. As the porous film to be used, a film whose surface is roughened by a mold or a blast treatment is preferable.

The reinforced electrolyte membrane of the present invention to them as materials, a small amount of Pt amount, or the H ₂ and O ₂ passing through to the electrolyte membrane bulk is converted to H _{2 O,} eluted from the catalyst layer, deposited, grown Pt A short circuit of the fuel battery cell due to the acicular precipitate can be prevented.

  Usually, the fuel electrode and the oxygen electrode are each composed of two layers: a catalyst layer containing a catalyst in which platinum or the like is supported on carbon particles, and a diffusion layer made of a porous material capable of diffusing a gas such as carbon cloth. The In this case, the fuel cell membrane-electrode assembly of the present invention may be produced by forming a catalyst layer and a diffusion layer on both sides of the electrolyte. For example, the catalyst of each electrode is dispersed in a liquid containing a polymer that is a material of the polymer film that serves as an electrolyte, and the dispersion is applied to both surfaces of the polymer film and dried to form a catalyst layer. Then, a diffusion layer may be formed on the surface of each formed catalyst layer by press-bonding carbon cloth or the like to form a membrane-electrode assembly.

  The electrolyte in the membrane-electrode assembly for a fuel cell of the present invention may be a laminate of a plurality of reinforcing porous membranes. In this case, at least one porous membrane among the plurality of porous membranes is the reinforced electrolyte membrane of the present invention. The electrolyte membrane to be laminated is not particularly limited as long as it is a polymer membrane that can be used as an electrolyte. The laminated electrolyte membranes may be the same electrolyte membrane, or different types of electrolyte membranes may be mixed and used. For example, perfluorinated sulfonic acid films, perfluorinated phosphonic acid films, perfluorinated carboxylic acid films, and perfluorinated films such as PTFE composite films in which polytetrafluoroethylene (PTFE) is compounded with these perfluorinated films. An electrolyte membrane, a hydrocarbon-based electrolyte membrane such as a fluorine-containing hydrocarbon-based graft membrane, a wholly hydrocarbon-based graft membrane, or a wholly aromatic membrane can be used.

  In particular, when considering durability and the like, it is desirable to use a perfluorinated electrolyte membrane. Among these, it is desirable to use a perfluorinated sulfonic acid membrane because of its high performance as an electrolyte. As an example of a perfluorinated sulfonic acid membrane, there is a copolymer membrane of perfluorovinyl ether having a sulfonic acid group and tetrafluoroethylene, which is known under the trade name “Nafion” (registered trademark, manufactured by DuPont).

  In consideration of cost and the like, it is desirable to use a hydrocarbon-based electrolyte membrane. Specifically, sulfonic acid type ethylenetetrafluoroethylene copolymer-graft-polystyrene membrane (hereinafter referred to as “sulfonic acid type ETFE-g-PSt membrane”), sulfonic acid type polyethersulfone membrane, sulfonic acid type poly Ether ether ketone film, sulfonic acid type crosslinked polystyrene film, sulfonic acid type polytrifluorostyrene film, sulfonic acid type poly (2,3-diphenyl-1,4-phenylene oxide) film, sulfonic acid type polyallyl ether ketone film, Examples thereof include a sulfonic acid type poly (arylene ether sulfone) film, a sulfonic acid type polyimide film, and a sulfonic acid type polyamide film. In particular, it is desirable to use a sulfonic acid type ETFE-g-PSt membrane for reasons such as low cost and high performance.

  The thickness of the porous membrane in the reinforced electrolyte membrane of the present invention is not particularly limited. For example, the thickness of both catalyst layers is preferably 1 to 10 μm, the thickness of all the electrolyte layers is preferably 10 to 100 μm, and the thickness of one porous membrane layer is preferably 1 to 10 μm from the viewpoint of suppressing cross leaks.

  The polymer electrolyte fuel cell of the present invention is a polymer electrolyte fuel cell using the above-described fuel cell membrane-electrode assembly of the present invention. Except for using the membrane-electrode assembly for a fuel cell of the present invention, the structure of a generally known polymer electrolyte fuel cell may be followed. By using the fuel cell membrane-electrode assembly of the present invention, the solid polymer fuel cell of the present invention is a solid polymer fuel cell having a large output, low cost and high durability.

Embodiment of the present invention [Embodiment 1]
A PTFE porous thin film having a thickness of 10 μm, a porosity of 70%, and a pore diameter of 0.3 μm was immersed in acetone and degreased and washed. This thin film was immersed in a tin (II) chloride SnCl ₄ / hydrochloric acid / methyl sulfoxide solution for 60 seconds and then washed with water. Next, it was immersed in an aqueous palladium chloride PdCl ₄ solution to precipitate Pd. The Pd-coated porous PTFE thin film was immersed in a hydrazine chloride / chloroplatinic acid hexahydrate H ₂ PtCl ₆ .6H ₂ O / dimethylsulfoxide aqueous solution and heated at 40 ° C. for 6 minutes to perform Pt plating. As a result, a Pt deposited film (0.02 mg / cm ² ) was observed in the range of 0.2 to 0.5 μm from the surface of the porous thin film.

  The Pt-coated PTFE porous thin film prepared by the above method was coated with an aqueous alcohol solution in which perfluorosulfonic acid resin was dispersed (filled with electrolyte in the porous film) and dried twice. (2 layers) / perfluorosulfonic acid composite membrane was obtained.

Using this membrane, a MEA was formed by a conventional method, and a power generation test was conducted for a long time. As a result of measuring the amount of cross-linked H _{2, the} amount of leaked H ₂ was 0.003 MPa at 1000 hours.

[Comparative Example 1]
An aqueous alcohol solution in which perfluorosulfonic acid resin added with Pt fine particles (1 μm diameter) of Example 1 was dispersed was applied to the same PTFE porous thin film as in Example 1 and dried to obtain a PTFE porous thin film (2 layers) / per A fluorosulfonic acid composite membrane was obtained. As a result of conducting the same power generation test, the amount of leaked H ₂ was 0.03 MPa or more at 1000 hours.

[Example 2]
Using the same substrate as in Example 1, a Pt-coated PTFE porous thin film (2 layers) / perfluorosulfonic acid composite membrane was obtained by the same method. This film was sandwiched between Pt black electrodes, and 1.25 Vvs. When Pt was deposited on the cathode side by a constant voltage electrolysis method using NHE, there was no short circuit during the test period.

[Comparative Example 2]
Using the PTFE porous thin film (2 layers) / perfluorosulfonic acid composite membrane of Comparative Example 1, the same constant voltage electrolysis test as in Example 2 was conducted, and as a result, a short circuit occurred after 7 hours. After the test, the test cell was disassembled, and Pt deposits penetrating the electrolyte were observed.

  The electrolyte membrane for a fuel cell of the present invention has a high probability that the gas that has permeated the electrolyte membrane and the noble metal are in contact with each other, and the permeated hydrogen reacts with oxygen to generate heat and degrade the membrane, and also prevents the noble metal. Short circuit due to deposition can be suppressed, and the durability and life of the fuel cell can be reduced. In addition, by using a fuel cell membrane-electrode assembly in which cross leakage is suppressed, a solid polymer fuel cell having high output and excellent durability can be obtained. This contributes to the practical application and spread of fuel cells.

A case where cross leak occurs and a case where cross leak occurs but is suppressed by Pt fine particles in the electrolyte membrane are shown. The schematic diagram of the principle by which cross leak is suppressed when the reinforcement type | mold electrolyte membrane of this invention is used is shown.

Explanation of symbols

1: anode catalyst layer, 2: cathode catalyst layer, 3: electrolyte membrane, 4: noble metal fine particles, 5: porous membrane.

Claims (17)

  A fuel cell electrolyte membrane reinforced with a porous thin film, wherein a noble metal is coated and / or deposited on the surface and / or pores of the porous membrane. film.   2. The fuel cell reinforcement according to claim 1, wherein the fuel cell electrolyte membrane reinforced with the porous thin film is a fuel cell reinforced electrolyte membrane in which a porous thin film is impregnated with a polymer electrolyte. Type electrolyte membrane.   The fuel cell electrolyte membrane reinforced with the porous thin film is a fuel cell reinforced electrolyte membrane in which one or more sets of polymer electrolyte membranes and a porous thin film are laminated. Reinforced electrolyte membrane for fuel cells.   The reinforced electrolyte membrane for a fuel cell according to any one of claims 1 to 3, wherein an average pore diameter of the porous thin film is 0.1 µm or more.   The fuel cell reinforcing electrolyte membrane according to any one of claims 1 to 4, wherein the porosity of the porous thin film is 40% or more.   The reinforced electrolyte membrane for a fuel cell according to any one of claims 1 to 5, wherein the porous thin film is a polytetrafluoroethylene (PTFE) membrane made porous by a stretching method.   The reinforced electrolyte membrane for a fuel cell according to any one of claims 1 to 6, wherein the noble metal is platinum (Pt).   A step of coating and / or depositing a noble metal on the surface and / or pores of the porous film by treating the porous thin film with a compound solution having a noble metal ion species, and a porous material covering and / or encapsulating the noble metal A method for producing a reinforced electrolyte membrane for a fuel cell, comprising: filling a thin film with a polymer electrolyte.   A step of coating and / or depositing a noble metal on the surface and / or pores of the porous film by treating the porous thin film with a compound solution having a noble metal ion species, and a porous material covering and / or encapsulating the noble metal A method for producing a reinforced electrolyte membrane for a fuel cell, comprising: laminating a polymer electrolyte membrane on a thin film.   The reinforced electrolyte membrane for a fuel cell according to claim 8 or 9, wherein the step of coating and / or depositing a noble metal on the surface and / or pores of the porous thin film is chemical plating or sputtering. Manufacturing method.   The method for producing a reinforced electrolyte membrane for a fuel cell according to any one of claims 8 to 10, wherein an average pore diameter of the porous thin film is 0.1 µm or more.   The method for producing a reinforced electrolyte membrane for a fuel cell according to any one of claims 8 to 11, wherein the porosity of the porous thin film is 40% or more.   The method for producing a reinforced electrolyte membrane for a fuel cell according to any one of claims 8 to 12, wherein the porous thin film is a polytetrafluoroethylene (PTFE) membrane made porous by a stretching method. .   The method for producing a reinforced electrolyte membrane for a fuel cell according to any one of claims 8 to 13, wherein the noble metal is platinum (Pt).   A membrane-electrode for a fuel cell, comprising a pair of electrodes comprising a fuel electrode supplied with fuel gas and an oxygen electrode supplied with oxidant gas, and a polymer electrolyte membrane sandwiched between the pair of electrodes A membrane-electrode assembly for a fuel cell, wherein the polymer electrolyte membrane is a reinforced electrolyte membrane for a fuel cell according to any one of claims 1 to 7.   16. The fuel cell membrane-electrode assembly according to claim 15, wherein the polymer electrolyte membrane includes a plurality of reinforced electrolyte membranes for the fuel cell.   A polymer electrolyte fuel cell comprising a membrane-electrode assembly having the reinforced electrolyte membrane for a fuel cell according to any one of claims 1 to 7.

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