JP2008243378A - Membrane electrode assembly for fuel cell, and fuel cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for sufficiently suppressing deterioration of an electrolyte membrane and for enhancing durability of a PEFC, in the PEFC. <P>SOLUTION: In a membrane electrode assembly for a fuel cell having a solid polymer electrolyte membrane; a cathode gas diffusion electrode arranged on one surface of the solid polymer electrolyte membrane and containing a cathode catalyst layer and a cathode gas diffusion layer, and an anode gas diffusion electrode arranged on the other surface of the solid polymer electrolyte membrane and containing an anode catalyst layer and an anode gas diffusion layer, a chlorine capture layer containing a chlorine capture material is arranged in at least one of the solid polymer electrolyte membrane, the cathode gas diffusion electrode, and the anode gas diffusion electrode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a membrane electrode assembly for a fuel cell and a fuel cell using the same.

  A polymer electrolyte fuel cell (PEFC) generally has a structure in which a membrane electrode assembly (MEA) is sandwiched between a pair of separators. In the MEA, the solid polymer electrolyte membrane is formed by a pair of gas diffusion electrodes (a cathode gas diffusion electrode composed of a cathode catalyst layer and a cathode gas diffusion layer, an anode gas diffusion electrode composed of an anode catalyst layer and an anode gas diffusion layer). It has a configuration of being sandwiched. The catalyst layer includes an electrode catalyst and a proton conductive solid polymer electrolyte, and has a porous structure in order to diffuse reaction gas supplied from the outside. The electrode catalyst generally has a structure in which a catalyst component is supported on a conductive carrier. Furthermore, the gas diffusion layer also has a porous structure, and is generally composed of conductive carbon fibers.

  In the PEFC MEA, the following electrochemical reaction proceeds. First, hydrogen contained in the fuel gas supplied to the anode side is oxidized by the catalyst component in the anode catalyst layer to become protons and electrons. The produced protons then reach the cathode catalyst layer through the solid polymer electrolyte contained in the anode catalyst layer and further through the solid polymer electrolyte membrane in contact with the anode catalyst layer. On the other hand, the electrons generated in the anode catalyst layer include the conductive carrier constituting the anode catalyst layer, the gas diffusion layer in contact with the side of the anode catalyst layer facing the solid polymer electrolyte membrane, the separator, and the outside. It reaches the cathode catalyst layer through the circuit. The protons and electrons that have reached the cathode catalyst layer react with oxygen contained in the oxidant gas supplied to the cathode catalyst layer to produce water. In PEFC, electricity can be taken out through the above-described electrochemical reaction.

  Considering applications that require high power generation performance over a long period of time such as in-vehicle PEFC, it is required to further improve the durability of each member constituting PEFC. R & D has been done.

Here, for example, as a deterioration mechanism of the solid polymer electrolyte membrane which is a main member of PEFC, the involvement of radicals derived from hydrogen peroxide (H ₂ O ₂ ) generated at the cathode or anode during operation of PEFC is estimated. Yes. Based on this knowledge, a technology to improve the durability of electrolyte membranes against hydrogen peroxide by dispersing and blending carbon materials (carbon black, activated carbon, carbon nanotubes, etc.) that have been subjected to ozone treatment to solid polymer electrolyte membranes. It has been proposed (see, for example, Patent Document 1). According to this technique, the quinone carbonyl group modified on the surface of the ozone-treated carbon material exerts a radical scavenging function or a radical decomposition function, thereby suppressing the deterioration of the electrolyte membrane.

In addition, for the purpose of suppressing deterioration of the electrolyte membrane caused by hydrogen peroxide generated at the cathode, a technique for arranging a radical scavenging layer between the electrolyte membrane constituting the MEA and the cathode catalyst layer has been proposed (for example, , See Non-Patent Document 1). According to Non-Patent Document 1, it is disclosed that a rare earth element is particularly preferable as a radical scavenger.
JP 2004-152615 A 2005 NEDO Fuel Cell / Hydrogen Technology Development Results Report Meeting, Strategic Technology Development Project for Solid Polymer Fuel Cell Practical Use, Elemental Technology Development, “Research and Development of DSS-Compliant Long Life Battery Technology”

  However, it cannot be said that the deterioration of the electrolyte membrane can be sufficiently suppressed even by the conventionally proposed technology, and the development of means capable of suppressing the deterioration of the electrolyte membrane and further improving the durability of the PEFC is desired. This is the current situation.

  Therefore, an object of the present invention is to provide a technique that can sufficiently suppress deterioration of an electrolyte membrane and contribute to improvement of durability of the PEFC in PEFC.

In view of the above situation, the present inventors have conducted intensive research. In the process, first, the hydrogen peroxide generation mechanism, which is the cause of electrolyte membrane degradation, was investigated in more detail. As a result, (1) with the operation of PEFC, platinum ions (Pt ²⁺ ) eluted from the cathode catalyst layer move into the electrolyte membrane, and at a certain distance from the interface between the cathode catalyst layer and the electrolyte membrane. Reduced and deposited in a layered form (hereinafter, this platinum deposition site is also referred to as “platinum band”) (see FIG. 1). (2) Hydrogen peroxide is generated in the platinum band. Deterioration of the electrolyte membrane proceeds as a starting point, (3) Chlorine is adsorbed on platinum deposited in the platinum band (see FIG. 2), and (4) Amount of chlorine adsorbed on platinum It has been found that the reduction reduces the production of hydrogen peroxide. FIG. 1 is a photograph taken by a scanning electron microscope (SEM) of a vertical section of a single cell after an OCV test on a PEFC single cell. FIG. 2 is a photograph of a platinum band in a vertical cross section of a single cell taken with a transmission electron microscope energy dispersive X-ray analyzer (TEM-EDX). The light emitting site in FIG. The site | part which exists exists and the luminescent site | part in FIG.2 (b) points out the site | part in which chlorine exists.

  Based on the above knowledge, the supply source of chlorine adsorbed on platinum is an oxidant gas (eg, air) supplied to the cathode during PEFC operation, a fuel gas (eg, hydrogen) supplied to the anode, and a gas diffusion electrode. In view of the material to be formed, the present inventors have suppressed the generation of hydrogen peroxide in the platinum band by disposing a chlorine trapping layer containing a chlorine trapping material at any location of the MEA constituting the PEFC. As a result, it has been found that the durability of PEFC can be improved, and the present invention has been completed.

  That is, the present invention includes a solid polymer electrolyte membrane, a cathode gas diffusion electrode including a cathode catalyst layer and a cathode gas diffusion layer disposed on one surface of the solid polymer electrolyte membrane, and the solid polymer electrolyte membrane. An anode gas diffusion electrode including an anode catalyst layer and an anode gas diffusion layer disposed on the other surface of the solid polymer electrolyte membrane, the cathode gas diffusion electrode, or the anode gas diffusion electrode. One is a MEA for a fuel cell in which a chlorine capturing layer including a chlorine capturing material is disposed.

  According to the MEA for fuel cell of the present invention, in the PEFC, the generation of hydrogen peroxide in the platinum band can be suppressed, and as a result, the durability of the PEFC can be improved.

  The present invention relates to a solid polymer electrolyte membrane, a cathode gas diffusion electrode including a cathode catalyst layer and a cathode gas diffusion layer disposed on one surface of the solid polymer electrolyte membrane, and the other of the solid polymer electrolyte membranes An anode gas diffusion electrode including an anode catalyst layer and an anode gas diffusion layer disposed on the surface of the solid polymer electrolyte membrane, the cathode gas diffusion electrode, or the anode gas diffusion electrode. The membrane electrode assembly for fuel cells, wherein a chlorine capturing layer containing a chlorine capturing material is disposed.

  Hereinafter, several preferred embodiments of the MEA of the present invention will be described in detail with reference to the drawings. Each drawing is exaggerated for convenience of explanation, and the dimensional ratio of each component in each drawing may be different from the actual one.

(First embodiment)
First, the first embodiment will be described.

  FIG. 3 is a schematic cross-sectional view of the membrane electrode assembly (MEA) of the first embodiment.

  The MEA 100 shown in FIG. 3 includes a solid polymer electrolyte membrane 110, a cathode gas diffusion electrode 120c including a cathode catalyst layer 122c and a cathode gas diffusion layer 124c disposed on one surface of the solid polymer electrolyte membrane 110, An anode gas diffusion electrode 120a including an anode catalyst layer 122a and an anode gas diffusion layer 124a disposed on the other surface of the solid polymer electrolyte membrane 110; In the present application, the “membrane electrode assembly (MEA)” is an assembly having a solid polymer electrolyte membrane 110 and a pair of gas diffusion electrodes (120c, 120a) sandwiching the solid polymer electrolyte membrane 110. Means the body.

  In the MEA 100 of the present embodiment, as shown in FIG. 3, a chlorine capturing layer 180c is disposed in a portion of the solid polymer electrolyte membrane 110 near the cathode catalyst layer 122c so as not to be adjacent to the cathode catalyst layer 122c. Yes. A chlorine capturing layer 180a is disposed at a portion of the solid polymer electrolyte membrane 110 near the anode catalyst layer 122a so as to be adjacent to the anode catalyst layer 122a. These chlorine capturing layers 180 include a chlorine capturing material (not shown). Details of the chlorine trapping layer and the chlorine trapping material will be described later.

FIG. 3 also shows a platinum band 190. As described above, the platinum band 190 is a portion where platinum ions (Pt ²⁺ ) eluted from the cathode catalyst layer move into the electrolyte membrane and are reduced and deposited in a layered manner with the PEFC operation. There is no platinum band in the MEA before operation. The portion of the solid polymer electrolyte membrane 110 after PEFC operation where the platinum band 190 exists (distance from the cathode catalyst layer) varies depending on PEFC operation conditions (eg, temperature, humidity, supply gas composition, etc.). Therefore, it is difficult to define uniquely. However, according to the study by the present inventors, the permeability coefficients of the solid polymer electrolyte membrane with respect to oxygen and hydrogen under the temperature and humidity conditions during operation of the PEFC are P _O2 and P _H2 , respectively, and are supplied to the cathode. that the partial pressure of hydrogen in the oxygen partial pressure and the fuel gas supplied to the anode of the oxidizing gas was a p _O2 and p _H2, respectively, the thickness of the solid polymer electrolyte membrane when is L, the solid high The distance d from the interface between the molecular electrolyte membrane and the cathode catalyst layer is expressed by the following formula 1:

It was found that reduction deposition of platinum (platinum band 190) occurs centering on the surface represented by the above (in this application, this surface is also referred to as “predicted precipitation surface”).

  Here, an experiment supporting the above-described theory about the position of the predicted precipitation surface will be described. FIG. 4 is a photograph taken with a transmission electron microscope (TEM) of the formation position of the platinum band when the composition of the oxidant gas supplied to the cathode and the fuel gas supplied to the anode is changed in the OCV test. is there. The gas supply conditions at the time of the OCV test are almost normal pressure conditions (110 kPa_abs), the supply gas composition (oxidant gas / fuel gas) is as follows: Sample 1: pure oxygen / 10 volume% hydrogen-containing nitrogen, Sample 2: Pure oxygen / pure hydrogen, sample 3: pure hydrogen / air.

  From the results shown in FIG. 4, when the oxygen partial pressure and nitrogen partial pressure in the supply gas are changed, the position of the platinum band 190 generated in the solid polymer electrolyte membrane 110 during PEFC operation changes accordingly. I understand.

  During operation of a PEFC (not shown) including the MEA of this embodiment, an oxidant gas is supplied to the cathode and a fuel gas is supplied to the anode. Chlorine (chloride ions) contained in these supply gases ) Is trapped by the chlorine trapping material contained in the chlorine trapping layer 180 when it moves in the solid polymer electrolyte membrane 110 in the MEA stacking direction. As a result, the amount of chlorine (chloride ions) reaching the site where the platinum band 190 is generated (that is, the expected precipitation surface) is reduced, and the generation of hydrogen peroxide in the platinum band 190 is suppressed. Finally, the deterioration of the solid polymer electrolyte membrane 110 due to the generation of hydrogen peroxide is alleviated, and the durability of the PEFC can be improved.

  In view of the above knowledge, in the present embodiment, the chlorine trapping layers (180c, 180a) are formed on the cathode side (chlorine trapping layer 180c) and anode side (chlorine) with respect to the predicted precipitation surface (= the surface where the platinum band 190 is located). It is arranged on both of the acquisition layers 180a). According to such a configuration, chlorine (chloride ions) contained in the oxidant gas flowing from the cathode toward the predicted precipitation surface is trapped in the chlorine trapping layer 180c, and the fuel flows from the anode toward the predicted precipitation surface. Chlorine (chloride ions) contained in the gas is captured in the chlorine capturing layer 180a. As a result, the operational effects obtained by arranging the chlorine capturing layer can be more remarkably exhibited. However, the technical scope of the present invention is not limited to such a form, and a form in which the chlorine capturing layer is disposed only on either the cathode side or the anode side can also be adopted.

  Note that the above-described mechanism is merely based on speculation, and the technical scope of the present invention is not affected at all even if the operational effects of the present invention are obtained by different mechanisms. This is also valid for each of the other preferred forms of mechanisms described below.

  As described above, the MEA of the present invention and the PEFC including the MEA are characterized in that a chlorine capturing layer is disposed. Therefore, the MEA and PEFC configurations other than the characteristic configuration may be appropriately changed or modified based on conventionally known knowledge.

  Hereinafter, the components of the MEA of the present embodiment will be described with reference to the drawings, and then the chlorine capturing layer, which is a characteristic configuration of the MEA of the present invention, will be described. The technical scope of the present invention is claimed. Should be determined based on the scope description.

[Solid polymer electrolyte membrane]
The solid polymer electrolyte membrane 110 is composed of a proton-conducting solid polymer electrolyte (hereinafter also simply referred to as “ionomer”), and protons generated in the anode catalyst layer 122a during the PEFC operation are cathodized along the film thickness direction. It has a function of selectively permeating into the catalyst layer 122c. The solid polymer electrolyte membrane 110 also has a function as a partition for preventing the fuel gas supplied to the anode side and the oxidant gas supplied to the cathode side from being mixed.

  The specific configuration of the solid polymer electrolyte membrane 110 is not particularly limited, and a conventionally known ionomer membrane can be appropriately employed in the technical field of fuel cells. The solid polymer electrolyte membrane 110 is roughly classified into a fluorine-based solid polymer electrolyte membrane and a hydrocarbon-based solid polymer electrolyte membrane according to the type of ionomer that is a constituent material.

  Examples of the fluorine-based solid polymer electrolyte include perfluorocarbon sulfonic acids such as Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), and the like. Polymer, perfluorocarbon phosphonic acid polymer, trifluorostyrene sulfonic acid polymer, ethylene tetrafluoroethylene-g-styrene sulfonic acid polymer, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride-perfluorocarbon sulfonic acid polymer Etc. From the viewpoint of power generation performance such as heat resistance and chemical stability, these fluorine-based solid polymer electrolyte membranes are preferably used, and particularly preferably a fluorine-based solid polymer electrolyte membrane composed of a perfluorocarbon sulfonic acid polymer. Is used.

  Examples of the hydrocarbon solid polymer electrolyte include sulfonated polyethersulfone (S-PES), sulfonated polyaryletherketone, sulfonated polybenzimidazole alkyl, phosphonated polybenzimidazole alkyl, sulfonated polystyrene, and sulfonated. Examples include polyetheretherketone (S-PEEK) and sulfonated polyphenylene (S-PPP). These hydrocarbon-based solid polymer electrolyte membranes are preferably used from the viewpoint of production such that the raw materials are inexpensive, the production process is simple, and the material selectivity is high. In addition, as for the ion exchange resin mentioned above, only 1 type may be used independently and 2 or more types may be used together.

  Materials other than the ionomer constituting the solid polymer electrolyte membrane described above may be used as the ionomer. As such materials, for example, liquids, solids, and gel materials having high proton conductivity can be used, and solid acids such as phosphoric acid, sulfuric acid, antimonic acid, stannic acid, and heteropoly acid, phosphoric acid, and the like. Hydrocarbon polymer compound doped with a non-organic acid, organic / inorganic hybrid polymer partially substituted with proton conductive functional group, gel impregnated with phosphoric acid solution or sulfuric acid solution in polymer matrix An example is a proton conductive material. A mixed conductor having both proton conductivity and electron conductivity can also be used as an ionomer.

  The thickness of the solid polymer electrolyte membrane 110 is appropriately determined in consideration of the characteristics of the MEA 100 and PEFC, and is not particularly limited. However, the thickness of the solid polymer electrolyte membrane 110 is preferably 5 to 300 μm, more preferably 5 to 200 μm, still more preferably 10 to 150 μm, and particularly preferably 15 to 50 μm. When the thickness is within such a range, the balance between strength during film formation, durability during use, and output characteristics during use can be appropriately controlled.

[Cathode gas diffusion electrode]
The cathode gas diffusion electrode 120c includes a cathode catalyst layer 122c and a cathode gas diffusion layer 124c.

  The cathode catalyst layer 122c is a layer containing an electrode catalyst on which a catalyst component is supported and an ionomer.

In the cathode catalyst layer 122c, the electrode catalyst is mainly composed of protons (H ⁺ ) via the solid polymer electrolyte membrane 110, electrons (e ⁻ ) via the external circuit, and oxygen (O ₂ ) derived from the oxidant gas. It has a function of promoting a reaction for generating water (that is, a reduction reaction of oxygen).

  Simply speaking, the electrode catalyst has a structure in which a catalyst component such as platinum is supported on the surface of a conductive carrier made of carbon or the like.

  The electroconductive carrier constituting the electrode catalyst may be any one having a specific surface area sufficient to support the catalyst component in a desired dispersed state and sufficient electron conductivity. In the composition of the conductive carrier, the main component is preferably carbon. Specific examples of the material for the conductive carrier include carbon black, activated carbon, coke, natural graphite, and artificial graphite. “The main component is carbon” means that the main component contains carbon atoms, and is a concept that includes both carbon atoms and substantially carbon atoms. In some cases, elements other than carbon atoms may be included in order to improve the characteristics of the fuel cell. Note that “substantially consisting of carbon atoms” means that contamination of about 2 to 3 mass% or less of impurities can be allowed.

The BET specific surface area of the conductive carrier is not particularly limited as long as it is a specific surface area sufficient to carry the catalyst component in a highly dispersed manner, but is preferably 100 to 1500 m ² / g, more preferably 600 to 1000 m. ² / g. When the specific surface area of the conductive support is in such a range, the balance between the dispersibility of the catalyst component on the conductive support and the effective utilization rate of the catalyst component can be appropriately controlled.

  Although there is no restriction | limiting in particular also about the average particle diameter of an electroconductive support | carrier, Usually, it is 5-200 nm, Preferably it is about 10-100 nm. In addition, as a value of “average particle diameter of the conductive carrier”, a value calculated by a primary particle diameter measurement method using a transmission electron microscope (TEM) is adopted.

  The catalyst component supported on the conductive carrier is not particularly limited as long as it has a function of catalytically promoting the oxygen reduction reaction described above, and a conventionally known catalyst component can be appropriately used. Specific examples of the catalyst component include platinum, ruthenium, iridium, rhodium, palladium, osmium, tungsten, lead, iron, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, aluminum, and alloys thereof. Etc. Among these, the catalyst component preferably contains at least platinum from the viewpoint of excellent catalytic activity, poisoning resistance to carbon monoxide and the like, and heat resistance. The composition of the alloy in the case of using an alloy as the catalyst component in the cathode catalyst layer 122c varies depending on the type of metal to be alloyed and the like, and can be appropriately selected by those skilled in the art, but is preferably about 30 to 90 atomic% platinum. The other metal to be converted is about 10 to 70 atomic%. Note that an “alloy” is a general term for a metal element having one or more metal elements or non-metal elements added and having metallic properties. The alloy structure consists of a eutectic alloy, which is a mixture of the component elements as separate crystals, a component element completely melted into a solid solution, and a component element composed of an intermetallic compound or a compound of a metal and a nonmetal. There is what is formed, and any may be used in the present application. Here, the alloy composition can be specified by using an ICP emission analysis method.

  The shape and size of the catalyst component are not particularly limited, and the same shape and size as those of conventionally known catalyst components can be adopted as appropriate, but the shape of the catalyst component is preferably granular. And the average particle diameter of a catalyst particle becomes like this. Preferably it is 1-30 nm, More preferably, it is 1.5-20 nm. When the average particle diameter of the catalyst particles is within such a range, the balance between the catalyst utilization rate related to the effective electrode area where the electrochemical reaction proceeds and the ease of loading can be appropriately controlled. In the present invention, the value of the “average particle diameter of the catalyst particles” is the particle diameter of the catalyst component determined from the crystallite diameter determined from the half-value width of the diffraction peak of the catalyst component in X-ray diffraction or the transmission electron microscope image. It can be calculated as an average value of diameters.

  The ratio of the content of the conductive support and the catalyst component in the electrode catalyst is not particularly limited. However, the content (supported amount) of the catalyst component is preferably 110 to 300% by mass, more preferably 130 to 250% by mass, and further preferably 150 to 200% based on 100% by mass of the conductive carrier. % By mass. When the content of the catalyst component is 100% by mass or more, the catalyst-producing ability of the electrode catalyst is sufficiently exerted, which can contribute to the improvement of the power generation performance of PEFC100. On the other hand, the catalyst component content of 300% by mass or less is preferable because aggregation of the catalyst components on the surface of the conductive support is suppressed and the catalyst components are highly dispersed and supported. In addition, as a value of the ratio of content mentioned above, the value measured by ICP emission spectrometry shall be employ | adopted.

  The cathode catalyst layer 122c further includes an ionomer in addition to the electrode catalyst described above. The specific form of the ionomer contained in the cathode catalyst layer 122c is not particularly limited, and conventionally known knowledge can be appropriately referred to in the technical field of fuel cells. For example, as the ionomer included in the cathode catalyst layer 122c, the ionomer that constitutes the above-described solid polymer electrolyte membrane 110 can be similarly used. Therefore, details of the specific form of the ionomer are omitted here. In addition, the ionomer contained in the cathode catalyst layer 122c may be one kind alone, or two or more kinds.

  The ion exchange capacity of the ionomer contained in the cathode catalyst layer 122c is preferably 0.9 to 1.5 mmol / g, and preferably 1.1 to 1.5 mmol / g, from the viewpoint of excellent ion conductivity. Is more preferable.

  The “ion exchange capacity” of an ionomer means the number of moles of sulfonic acid groups per unit dry mass of the ionomer. The value of “ion exchange capacity” can be calculated by removing the dispersion medium of the ionomer dispersion by heat drying or the like to obtain a solid polymer electrolyte, and performing neutralization titration.

  There is no particular limitation on the ionomer content in the cathode catalyst layer 122c. However, the ratio of the ionomer content to the conductive carrier content in the cathode catalyst layer 122c (ionomer / conductive carrier mass ratio) is preferably 0.5 to 2.0, more preferably 0.7. It is -1.5, More preferably, it is 0.9-1.3. The mass ratio of ionomer / conductive carrier is preferably 0.9 or more from the viewpoint of suppressing the internal resistance of the membrane / electrode assembly. On the other hand, an ionomer / conductive carrier mass ratio of 1.3 or less is preferable from the viewpoint of suppressing flooding.

  The cathode gas diffusion layer 124c is disposed on the surface of the cathode catalyst layer 122c described above facing the solid polymer electrolyte membrane 110. The cathode gas diffusion layer 124c has a function of promoting the diffusion of the oxidant gas supplied through a gas flow path of the separator described later to the cathode catalyst layer 122c and a function as an electron conduction path.

  The material constituting the base material of the cathode gas diffusion layer 124c is not particularly limited, and conventionally known knowledge can be referred to as appropriate. For example, a sheet-like material having conductivity and porosity such as a carbon woven fabric, a paper-like paper body, a felt, and a non-woven fabric can be used. The thickness of the substrate may be appropriately determined in consideration of the characteristics of the obtained gas diffusion layer, but may be about 30 to 500 μm. If the thickness of the substrate is within such a range, the balance between mechanical strength and diffusibility such as gas and water can be appropriately controlled.

  The cathode gas diffusion electrode 120c may further include other members (layers) as necessary. For example, in order to promote the discharge of excess moisture present in the cathode catalyst layer 122c and suppress the occurrence of the flooding phenomenon, the cathode gas diffusion layer 124c has a carbon particle layer containing carbon particles on the catalyst layer side of the substrate. You may have.

  The carbon particles contained in the carbon particle layer are not particularly limited, and conventionally known materials such as carbon black, graphite, and expanded graphite can be appropriately employed. Among them, carbon black such as oil furnace black, channel black, lamp black, thermal black, acetylene black and the like can be preferably used because of excellent electron conductivity and a large specific surface area. The average particle diameter of the carbon particles is preferably about 10 to 100 nm. Thereby, while being able to obtain the high drainage property by capillary force, it becomes possible to improve contact property with a catalyst layer.

  The carbon particle layer may contain a water repellent. Examples of the water repellent include fluorine-based polymer materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), polyhexafluoropropylene, and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). Examples include polypropylene and polyethylene. Among these, fluorine-based polymer materials can be preferably used because of excellent water repellency, corrosion resistance during electrode reaction, and the like.

[Anode gas diffusion electrode]
The anode gas diffusion electrode 120a includes an anode catalyst layer 122a and an anode gas diffusion layer 124a.

  The anode catalyst layer 122a is a layer containing an electrode catalyst on which a catalyst component is supported and an ionomer.

In the anode catalyst layer 122a, the electrode catalyst has a function of promoting a reaction in which hydrogen (H ₂ ) derived from fuel gas is converted into protons (H ⁺ ) and electrons (e ⁻ ) (that is, hydrogen oxidation reaction).

  As for the specific forms of the electrode catalyst and ionomer constituting the anode catalyst layer 122a, the forms described above in the column of the cathode catalyst layer 122c can be similarly adopted. Therefore, detailed description is omitted here. The cathode catalyst layer 122c and the anode catalyst layer 122a may have the same or different specific forms of electrode catalyst and ionomer that constitute the catalyst layer.

  In the MEA 100 of the present embodiment, the average thickness (Ya) of the anode catalyst layer 122a is preferably smaller than the average thickness (Yc) of the cathode catalyst layer 122c. When Ya is smaller than Yc, proton conduction to the cathode catalyst layer 122c is improved. Specifically, Ya / Yc is preferably 0.1 to 0.9, and more preferably 0.2 to 0.5. In addition, the average thickness of the anode catalyst layer 122a is preferably 1.0 to 20.0 μm, and more preferably 2.0 to 5.0 μm. In addition, as a value of the thickness of the catalyst layer, a value obtained by observing a cross section of the catalyst layer with a scanning electron microscope (SEM) is adopted.

  In the MEA 100 of the present embodiment, the anode catalyst layer 122a preferably has a single layer structure. This is because the anode catalyst layer 122a has a smaller difference in reactivity between the electrolyte membrane side and the gas diffusion layer side than the cathode catalyst layer 122c. This is because an increase in the layer average thickness due to the use of a plurality of layers can be avoided. However, embodiments in which the anode catalyst layer 122a has a laminated structure including two or more catalyst layers are also included in the technical scope of the present invention.

  As for a specific form of the anode gas diffusion layer 124a constituting the anode gas diffusion electrode 120a, the form described above in the column of the cathode gas diffusion layer 124c constituting the cathode gas diffusion electrode 120c can be similarly adopted. Therefore, detailed description is omitted here. In addition, the anode gas diffusion electrode 120a may further include a member (layer) such as a carbon particle layer as necessary, similarly to the cathode gas diffusion electrode 120c described above.

[Chlorine capture layer]
In the MEA 100 of the present embodiment, the chlorine capturing layer 180 (180c, 180a) is disposed inside the solid polymer electrolyte membrane 110 as described above. This chlorine trapping layer has a function of trapping chlorine (chloride ions) contained in the gas supplied during operation of the PEFC. Since the chlorine trapping layer 180 exhibits such a function, the adsorption of chlorine to the platinum deposited in the platinum band is suppressed, and the generation of hydrogen peroxide in the platinum band is suppressed. As a result, the solid polymer electrolyte membrane 110 The deterioration of PEFC can be alleviated and the durability of PEFC can be improved. As will be described later, in the present invention, a chlorine scavenging layer may be disposed on a member other than the solid polymer electrolyte membrane 110 constituting the MEA. However, as shown in FIG. It is preferable that a chlorine capturing layer is disposed inside. This is due to the following reason. That is, by disposing the chlorine trapping layer inside the solid polymer electrolyte membrane 110, most of the surface of the chlorine trapping material contained in the chlorine trapping layer can come into contact with moisture. Since chloride ions derived from the supply gas are thought to accompany water molecules when moving through the MEA, the efficiency of capturing chloride ions by the chlorine scavenger can be improved.

  The chlorine capturing layer 180 includes a chlorine capturing material. There is no restriction | limiting in particular about the material which comprises a chlorine capture | acquisition material, If it is a material which can capture | acquire the chlorine (chloride ion) contained in the gas supplied at the time of operation | movement of PEFC, it can employ | adopt suitably. Examples of the constituent material of the chlorine scavenger include carbon materials such as activated carbon, charcoal, carbon black, fullerene, and carbon nanotubes, and ceramics such as alumina, silica, zirconia, titania, tin oxide, and zeolite. Of these, activated carbon and zeolite are preferred as the chlorine-capturing material from the viewpoint that the water retention effect inside the solid polymer electrolyte membrane 110 is exhibited, power generation performance under dry conditions is maintained, and start-up performance below zero is improved. More preferred is activated carbon.

  The thickness of the chlorine capturing layer 180 is not particularly limited, and can be appropriately set within a range that does not affect the power generation performance of the PEFC. As an example, the thickness of the chlorine capturing layer 180 is preferably 0.1 to 30 μm, more preferably 0.5 to 20 μm, and further preferably 0.5 to 10 μm. If the thickness of the chlorine trapping layer 180 is 0.1 μm or more, the operational effect due to the arrangement of the chlorine trapping layer can be sufficiently exhibited. On the other hand, if the thickness of the chlorine trapping layer 180 is 30 μm or less, it is preferable from the viewpoint of reducing the size of the apparatus by thinning the electrolyte membrane as much as possible and improving low humidification operability. In the MEA 100 of the present invention, the number of chlorine capturing layers arranged may be only one layer, but may be a plurality of layers. In the case where a plurality of chlorine trapping layers are arranged, the “thickness of the chlorine trapping layer” means the thickness of each chlorine trapping layer.

  Moreover, there is no restriction | limiting in particular about the density in a surface (two-dimensional direction) of the chlorine capture | acquisition material which exists in the chlorine capture | acquisition layer 180. FIG. In addition, since the density can vary depending on the specific surface area of the material to be measured, it is difficult to define it unambiguously. However, the probability of trapping chlorine in the stacking direction in the chlorine trapping layer 180 (trapping rate). ), And proton conductivity in the stacking direction in the chlorine trapping layer 180 is approximately 0.1 to 50% by volume, preferably 0.5 to 40% by volume, more preferably 1 to 30% by volume. %.

  In the MEA 100 of the present embodiment, as shown in FIG. 3, a chlorine capturing layer 180c is disposed on the cathode side of the predicted precipitation surface so as not to be adjacent to the cathode catalyst layer 122c. According to such a form, the solid polymer electrolyte membrane 110 that does not contain a chlorine trapping material exists between the cathode catalyst layer 122c and the chlorine trapping layer 180c. The chlorine trapping layer 180c has many properties that easily hold not only chlorine but also water, and the chlorine trapping layer 180c having high water retention is not adjacent to the cathode catalyst layer 122c, so that occurrence of flooding phenomenon in the cathode gas diffusion electrode 120c is suppressed. , PEFC power generation performance can be prevented from decreasing. However, the present invention is not limited to such a form, and a form in which the chlorine capturing layer 180c disposed on the cathode side of the predicted precipitation surface is adjacent to the cathode catalyst layer 122c can also be adopted.

  Further, in the MEA 100 of the present embodiment, as shown in FIG. 3, a chlorine capturing layer 180a is disposed on the anode side of the predicted precipitation surface so as to be adjacent to the anode catalyst layer 122a. According to such a configuration, the chlorine trapping layer 180a has many properties that easily hold not only chlorine but also water, and the chlorine trapping layer 180a having high water retention is adjacent to the anode catalyst layer 122a. Occurrence of the dry-out phenomenon in can be suppressed, and the decrease in the power generation performance of PEFC can be suppressed.

  The MEA of the present invention has been described above in detail by taking the MEA of the first embodiment in which the chlorine capturing layer 180 is disposed inside the solid polymer electrolyte membrane 110 as an example. A chlorine capturing layer may be disposed on a member other than the electrolyte membrane 110, that is, a catalyst layer or a gas diffusion layer that constitutes the gas diffusion electrode. Specifically, for example, as shown in FIG. 5, a form in which the chlorine capturing layer 180 (180c, 180a) is disposed on the catalyst layer (cathode catalyst layer 122c, anode catalyst layer 122a) constituting the gas diffusion electrode, As shown in FIG. 6, there may be mentioned a form in which the chlorine capturing layer 180 (180c, 180a) is disposed in the gas diffusion layer (cathode gas diffusion layer 124c, anode gas diffusion layer 124a) constituting the gas diffusion electrode. 5 and 6 show a form in which the entire catalyst layer and gas diffusion layer are directly used as a chlorine capturing layer. However, the present invention is not limited to such a form. In FIG. Similarly to the case where the chlorine capturing layer 180 is disposed on a part of the electrolyte membrane 110, a form in which the chlorine capturing layer is disposed only on a part of the catalyst layer or the gas diffusion layer can also be adopted. Further, as shown in the figure, other than the form in which the chlorine capturing layer is disposed in both the cathode catalyst layer and the anode catalyst layer, and the form in which the chlorine capturing layer is disposed in both the cathode gas diffusion layer and the anode gas diffusion layer. In addition, a configuration in which the chlorine capturing layer is disposed only on either the cathode side or the anode side can also be adopted.

  There is no restriction | limiting in particular about the preparation methods of the chlorine capture layer 180 in MEA of this invention, It can produce suitably by referring a conventionally well-known knowledge. Hereinafter, although an example of the preparation method of such a chlorine capture layer is demonstrated, the technical scope of this invention is not limited only to the following form.

  First, a chlorine capture material is prepared. The prepared chlorine-capturing material may be pulverized as necessary for the purpose of controlling the particle size. On the other hand, a solution (electrolyte solution) in which the electrolyte is dissolved is prepared. As said electrolyte, the form mentioned above as an electrolyte which comprises a solid polymer electrolyte membrane can be employ | adopted similarly. The electrolyte of the electrolyte solution and the electrolyte constituting the solid polymer electrolyte membrane may be the same or different. And the prepared chlorine capture | acquisition material is mixed with the prepared electrolyte solution, and it is set as a capture | acquisition material solution. The trapping material solution may be subjected to stirring defoaming treatment, ultrasonic treatment, or the like as necessary. By adjusting the content of the electrolyte and chlorine trapping material in the prepared trapping material solution, the density of the prepared chlorine trapping layer can be controlled.

  Next, a desired amount of a capturing material solution is cast on the surface of a separately prepared solid polymer electrolyte membrane so as to obtain a desired size and thickness, then dried as necessary, and finally solidified. It is possible to produce a chlorine scavenging layer adjacent to the solid polymer electrolyte membrane. And MEA can be manufactured by forming a catalyst layer and a gas diffusion layer one by one by a conventional method further on the obtained chlorine capture layer.

  In the case of producing an MEA in which an electrolyte layer (electrolyte film) that does not include a chlorine scavenger is present between the chlorine trap layer 180 and the catalyst layer 122 as in the cathode side of the form shown in FIG. An electrolyte solution that does not contain a chlorine scavenger is further cast on the chlorine scavenger layer produced by the above method, and then dried and solidified as necessary to further form an electrolyte layer (electrolyte membrane) that does not contain a chlorine scavenger. That's fine. And MEA can be manufactured by forming a catalyst layer and a gas diffusion layer one by one by a conventional method further on the obtained layered product.

  Moreover, as a modification of the MEA of the first embodiment, for example, an MEA having the form shown in FIG. In the MEA 100 having the form shown in FIG. 7, reinforcing layers 140 (cathode side reinforcing layer 140 c and anode side reinforcing layer 140 a) are disposed on the solid polymer electrolyte membrane 110. The reinforcing layer 140 includes a reinforcing material and has a function of improving the physical strength of the solid polymer electrolyte membrane 110. In the form shown in FIG. 7, a chlorine capturing material is supported on the reinforcing material included in the reinforcing layer 140. According to the form shown in FIG. 7, it goes without saying that the effect of suppressing the production of hydrogen peroxide similar to that of the MEA of the first embodiment and the effect of mitigating deterioration of the electrolyte membrane accompanying this are exhibited. In addition to this, the effect of improving the strength of the solid polymer electrolyte membrane 110 and the fact that the reinforcing material may be disposed on the electrolyte membrane after the chlorine-capturing material is previously supported on the reinforcing material. Another function and effect of facilitating control of the arrangement position of the trapping layer can also be exhibited.

  There is no restriction | limiting in particular about the specific form of the reinforcing material which comprises the reinforcing layer 140, A conventionally well-known knowledge can be referred suitably as a reinforcing layer (reinforcing material) of an electrolyte membrane. Examples of the conventionally known material as the reinforcing material include, for example, a polytetrafluoroethylene porous material described in JP-A-8-162132.

  In order to produce such a form of MEA, first, as described above, a chlorine scavenger and an electrolyte solution are prepared, and a scavenger solution is prepared. Then, the reinforcing material is immersed in the prepared capturing material solution to suck the solution, and the chlorine capturing material is supported on the reinforcing material. Note that a surfactant may be added to the solution for the purpose of improving the controllability of the step of supporting the capturing material solution on the reinforcing material. Thereafter, the reinforcing material carrying the chlorine-capturing material is disposed so as to be adjacent to the solid polymer electrolyte membrane by drying as necessary and finally solidifying. And MEA can be manufactured by forming a catalyst layer and a gas diffusion layer one by one by a conventional method further on the obtained layered product.

  Furthermore, as another modified example of the MEA of the first embodiment, for example, an MEA having a form shown in FIG. In the MEA 100 of the form shown in FIG. 8, in addition to the two chlorine trap layers (180c, 180a) disposed on the electrolyte membrane, the chlorine trap material is dispersed throughout the electrolyte membrane, and the chlorine trap material is dispersed. A solid polymer electrolyte membrane 110 ′ is formed. According to the form shown in FIG. 8, it is needless to say that the effect of suppressing the production of hydrogen peroxide similar to that of the MEA of the first embodiment and the effect of mitigating the deterioration of the electrolyte membrane associated therewith are exhibited. In addition to this, the water retention effect inside the solid polymer electrolyte membrane 110 is exhibited, and the power generation performance under the dry condition is maintained, and another operational effect that the sub-zero startability is improved can also be exhibited. In the embodiment shown in FIG. 8, an example in which the chlorine capturing material is dispersed throughout the electrolyte membrane in addition to the chlorine capturing layer is illustrated, but the technical scope of the present invention is limited to such a form. Is not limited. For example, a mode in which a chlorine trapping material is dispersed in a catalyst layer or a gas diffusion layer constituting a gas diffusion electrode can also be adopted.

  In order to produce an MEA in which a chlorine scavenger is dispersed throughout the electrolyte membrane, a membrane obtained by casting the scavenger solution described above may be used as the MEA solid polymer electrolyte membrane. In addition, in order to produce MEA in which a chlorine scavenger is dispersed in a catalyst layer, a desired amount of chlorine scavenger is added to a catalyst ink containing an electrode catalyst or ionomer that is usually used for forming a catalyst layer. Then, the catalyst layer may be formed according to a conventional method. Furthermore, in order to disperse the chlorine trapping material in the gas diffusion layer, the substrate may be impregnated with a solution in which the chlorine trapping material is dispersed and then dried. Examples of the solvent of the solution include water, alcohol, a mixture of water and alcohol, and the like. Further, the solution may contain a surfactant if necessary. MEA can be produced by a conventional method using the thus obtained capture material-supporting substrate. In addition, when not only a gas diffusion base material but a carbon particle layer is provided, you may disperse | distribute a chlorine capture | acquisition material in a carbon particle layer. The carbon particle layer having such a form may be added with a desired amount of a chlorine scavenger in addition to the carbon particles when the carbon particle layer is formed. Further, when the chlorine scavenger is dispersed in the gas diffusion base material or the carbon particle layer, heat treatment at a temperature higher than that in the drying step may be performed for the purpose of firing after the chlorine scavenger is dispersed.

(Second Embodiment)
Next, the second embodiment will be described.

  In the second embodiment, the polymer electrolyte fuel cell (PEFC) is configured using the MEA of the first embodiment.

  FIG. 9 is a schematic cross-sectional view of a polymer electrolyte fuel cell (PEFC) of the second embodiment. FIG. 9 shows a single cell of PEFC.

  A PEFC 200 illustrated in FIG. 9 includes the MEA 100 according to the first embodiment. In the PEFC 200, the MEA 100 is sandwiched between a pair of separators including a cathode separator 150c and an anode separator 150a. Here, the cathode gas diffusion layer 124c surface of the cathode separator 150c is provided with an oxidant gas flow path 152c through which oxidant gas flows during operation, and coolant flows through the opposite surface during operation. A cooling flow path (not shown) is provided. On the other hand, the anode gas diffusion layer 124a side surface of the anode separator 150a is provided with a fuel gas flow path 152a through which fuel gas flows during operation, and the coolant flows through the opposite surface during operation. A cooling channel (not shown) is provided. A gasket 160 is disposed around the PEFC 200 so as to surround the pair of gas diffusion electrodes (120c, 120a).

[Separator]
The separators (150c, 150a) have a function of electrically connecting each cell in series when a plurality of single cells of a fuel cell such as PEFC 200 are connected in series to form a fuel cell stack. The separator also functions as a partition that separates the fuel gas, the oxidant gas, and the coolant from each other. Therefore, as described above, each separator is provided with a gas flow path and a cooling flow path.

  As a material constituting the separator, conventionally known materials such as dense carbon graphite, carbon such as a carbon plate, and metal such as stainless steel can be appropriately used without limitation.

  The thickness and size of the separator and the shape and size of each channel provided are not particularly limited, and can be appropriately determined in consideration of the desired output characteristics of the obtained PEFC.

[gasket]
The gasket 160 is disposed around the PEFC 200 so as to surround the pair of gas diffusion electrodes (120c, 120a), and has a function of preventing the gas supplied to the catalyst layer from leaking to the outside.

  The material constituting the gasket 160 is not particularly limited, but rubber materials such as fluorine rubber, silicon rubber, ethylene propylene rubber (EPDM), polyisobutylene rubber, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) Fluorine polymer materials such as polyhexafluoropropylene and tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and thermoplastic resins such as polyolefin and polyester. Moreover, there is no restriction | limiting in particular also in the thickness of a gasket, Preferably it is 50 micrometers-2 mm, More preferably, what is necessary is just to be about 100 micrometers-1 mm.

(Third embodiment)
Subsequently, a third embodiment will be described.

  In the third embodiment, a fuel cell stack is configured using the PEFC of the second embodiment.

  For reference, FIG. 10 shows a schematic cross-sectional view of a fuel cell stack 300 in which a plurality of PEFCs 200 of the second embodiment are electrically connected in series.

  In the fuel cell stack 300, a plurality of PEFCs 200 of the second embodiment are electrically connected in series via separators (150c, 150a), and both ends are fixed by current collector plates 310 and end plates 320. . Here, in the center of the two gas flow paths (fuel gas flow path: 152a, oxidant gas flow path: 152c) of the separator, a cooling flow path 330 for circulating a coolant (refrigerant) is provided. . By changing the number of single cells of PEFC 200 that are electrically connected in series in the fuel cell stack 300, the fuel cell stack 300 having a desired voltage can be configured. The shape of the fuel cell is not particularly limited, and may be determined as appropriate so that desired battery characteristics such as voltage can be obtained.

  Further, a vehicle equipped with the above-described PEFC or fuel cell stack of the present invention is also included in the technical scope of the present invention. Since the PEFC and fuel cell stack of the present invention are very excellent in output performance, they are suitable for vehicle applications that require high output.

It is the photograph which image | photographed the vertical cross section of the single cell after the OCV test with respect to a PEFC single cell with the scanning electron microscope (SEM). It is the photograph which image | photographed the platinum band in the vertical cross section of a single cell with the transmission electron microscope energy dispersive X-ray analyzer (TEM-EDX). The light emitting site in FIG. 2A indicates a site where platinum exists, and the light emitting site in FIG. 2B indicates a site where chlorine exists. It is a schematic cross section of the membrane electrode assembly (MEA) of 1st Embodiment. It is the photograph which image | photographed the production | generation position of the platinum band at the time of changing the composition of the oxidant gas supplied to a cathode in the OCV test, and the fuel gas supplied to an anode with the transmission electron microscope (TEM). The gas supply conditions at the time of the OCV test are almost normal pressure conditions (110 kPa_abs), the supply gas composition (oxidant gas / fuel gas) is as follows: Sample 1: pure oxygen / 10 volume% hydrogen-containing nitrogen, Sample 2: Pure oxygen / pure hydrogen, sample 3: pure hydrogen / air. It is a schematic cross section which shows the modification of MEA of 1st Embodiment. It is a schematic cross section which shows the other modification of MEA of 1st Embodiment. It is a schematic cross section which shows the other modification of MEA of 1st Embodiment. It is a schematic cross section which shows the other modification of MEA of 1st Embodiment. It is a schematic cross section of the polymer electrolyte fuel cell (PEFC) of 2nd Embodiment. It is a schematic cross section of the fuel cell stack formed by electrically connecting a plurality of PEFCs of the second embodiment in series.

Explanation of symbols

100 membrane electrode assembly (MEA),
110 solid polymer electrolyte membrane,
110 'a solid polymer electrolyte membrane in which a chlorine scavenger is dispersed;
120a anode gas diffusion electrode,
120c cathode gas diffusion electrode,
122a anode catalyst layer,
122c cathode catalyst layer,
124a anode gas diffusion layer,
124c cathode gas diffusion layer,
140 reinforcement layer,
140a anode side reinforcing layer,
140c cathode side reinforcing layer,
150a anode side separator,
150c cathode side separator,
152a fuel gas flow path,
152c oxidant gas flow path,
160 gasket,
180 chlorine capture layer,
180a anode side chlorine capture layer,
180c cathode side chlorine capturing layer,
190 Platinum Band,
200 polymer electrolyte fuel cell (PEFC; single cell),
300 fuel cell stack,
310 current collector,
320 end plate,
330 Cooling channel

Claims (11)

A solid polymer electrolyte membrane;
A cathode gas diffusion electrode including a cathode catalyst layer and a cathode gas diffusion layer, disposed on one surface of the solid polymer electrolyte membrane;
An anode gas diffusion electrode including an anode catalyst layer and an anode gas diffusion layer, disposed on the other surface of the solid polymer electrolyte membrane,
A fuel cell membrane electrode assembly, wherein a chlorine trapping layer containing a chlorine trapping material is disposed in at least one of the solid polymer electrolyte membrane, the cathode gas diffusion electrode, or the anode gas diffusion electrode. Oxidation supplied to the cathode with P _O2 and P _{H2 being} the permeation coefficients of the solid polymer electrolyte membrane with respect to oxygen and hydrogen under the temperature and humidity conditions during operation of the fuel cell including the membrane electrode assembly for a fuel cell the partial pressure of hydrogen in the fuel gas supplied to the partial pressure and the anode of the oxygen in the agent gas and p _O2 and p _H2, respectively, the thickness of the solid polymer electrolyte membrane when is L,
The distance d from the interface between the solid polymer electrolyte membrane and the cathode catalyst layer is expressed by the following formula 1:
The membrane electrode assembly for a fuel cell according to claim 1, wherein the chlorine capturing layer is disposed on both the cathode side and the anode side with respect to the predicted precipitation surface represented by   The membrane electrode assembly for a fuel cell according to claim 1 or 2, wherein the chlorine capturing layer is disposed inside the solid polymer electrolyte membrane.   The membrane electrode assembly for a fuel cell according to claim 3, wherein the chlorine trapping layer is disposed on the cathode side of the predicted precipitation surface so as not to be adjacent to the cathode catalyst layer.   The membrane electrode assembly for a fuel cell according to claim 3 or 4, wherein the chlorine trapping layer is disposed on the anode side of the predicted precipitation surface so as to be adjacent to the anode catalyst layer.   The membrane electrode assembly for a fuel cell according to any one of claims 1 to 5, wherein the chlorine trapping layer is disposed inside at least one of the cathode gas diffusion electrode or the anode gas diffusion electrode.   The fuel cell membrane according to any one of claims 1 to 6, wherein a reinforcing layer containing a reinforcing material is disposed on the solid polymer electrolyte membrane, and the chlorine capturing material is supported on the reinforcing material. Electrode assembly.   The chlorine scavenger is dispersed in a portion other than the portion where the chlorine trapping layer is disposed in at least one of the solid polymer electrolyte membrane, the cathode gas diffusion electrode, and the anode gas diffusion electrode. The membrane electrode assembly for fuel cells of any one of -7.   The fuel according to any one of claims 1 to 8, wherein the chlorine scavenger is one or more selected from the group consisting of activated carbon, charcoal, carbon black, fullerene, carbon nanotubes, and ceramics. Battery membrane electrode assembly. A fuel cell membrane electrode assembly according to any one of claims 1 to 9,
A pair of separators comprising a cathode separator and an anode separator sandwiching the membrane electrode assembly;
A fuel cell.   A vehicle equipped with the fuel cell according to claim 10.