Membrane-electrode assembly for fuel cell, manufacturing method thereof, and solid polymer fuel cell using membrane-electrode assembly

Abstract

By layering a gas expansion layer, which has a first conductive layer comprising a specific conductive carbon material and a specific high molecular weight polymer, on a catalyst layer in such a way that the catalyst layer and the first conductive layer are in contact and the high molecular weight polymer in the first conductive layer is present with greater density at the surface in contact with the catalyst layer than at the surface not in contact with the catalyst layer, it is possible to provide a membrane-electrode assembly having strong adhesion between the catalyst layer and gas expansion layer. In addition, by further employing a gas expansion layer, which has a second conductive layer comprising a specific conductive carbon material and a specific high molecular weight polymer, on the first conductive layer and layering the gas expansion layer on the catalyst layer in such a way that the high molecular weight polymer in the first conductive layer is present with greater density at the surface in contact with the catalyst layer than at the surface in contact with the second conductive layer and the high molecular weight polymer in the second conductive layer is present with greater density at the surface in contact with the first conductive layer than at the surface not in contact with the first conductive layer, it is possible to provide a membrane-electrode assembly for a fuel cell that suppresses positional offset between the catalyst layer and a conductive porous layer and between the conductive porous layer and a conductive porous base material.

Description

technical field [0001] The present invention relates to a membrane-electrode assembly for a fuel cell, a method for producing the same, and a polymer electrolyte fuel cell using the membrane-electrode assembly. Background technique [0002] A membrane-electrode assembly (MEA) constituting a polymer electrolyte fuel cell has a structure in which a gas diffusion layer, a catalyst layer, an ion-conducting solid polymer electrolyte membrane, a catalyst layer, and a gas diffusion layer are laminated in this order. [0003] The reaction of the polymer electrolyte fuel cell proceeds at the three-phase interface where the catalyst particles, the electrolyte, and the fuel gas in the catalyst layer are in contact. In order to obtain high power generation performance, the moisture generated by the electrode reaction at the three-phase interface is efficiently discharged to the outside of the electrode system, so that the fuel gas is supplied without delay, and the supplied fuel gas is ...

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Problems solved by technology

[0005] However, conventional membrane-electrode assemblies use only fluorine-based resins with a high glass transition temperature as in Patent Documents 1 and 2. Therefore, the adhesion between the conductive porous layer and the catalyst layer is poor and the battery performance is unstable. question

In addition, in order to improve the adhesion, it is necessary to join at a high temperature of 260°C or higher. In the case of such a process, the ion-conductive polymer electrolyte contained in the catalyst layer and the resin constituting the electrolyte membrane will deteriorate. It has a bad influence on the performance of the battery, so it is actually difficult to join under such conditions

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