Process for producing membrane/ electrode assembly for polymer electrolyte fuel cells

摘要

A process is provided whereby a membrane/electrode assembly for polymer electrolyte fuel cells whereby a high output voltage is obtainable within a wide range of current densities.;A process for producing a membrane/electrode assembly 1 comprising a first electrode 10 having a first catalyst layer 12 and a first gas diffusion layer 14, a second electrode 20 having a second catalyst layer 22 and a second gas diffusion layer 24, and an electrolyte membrane 30, wherein the first gas diffusion layer 14, a first intermediate having the first catalyst layer 12 formed on the surface of the electrolyte membrane 30 by coating followed by annealing, and a second intermediate having the second catalyst layer 22 formed on the surface of the second gas diffusion layer 24 by coating, are bonded, so that the first catalyst layer 12 is located between the first gas diffusion layer 14 and the electrolyte membrane 30, and the second catalyst layer 22 is located between the second gas diffusion layer 24 and the electrolyte membrane 30.

主权项

1. A process for producing a membrane/electrode assembly comprising a first electrode having a first catalyst layer and a first gas diffusion layer, a second electrode having a second catalyst layer and a second gas diffusion layer, and an electrolyte membrane interposed between the first electrode and the second electrode, which comprises:
applying a coating fluid comprising an ion exchange resin on a substrate, followed by annealing at from 100 to 250° C. to form an electrolyte membrane, and applying a coating fluid comprising an electrode catalyst and an ion exchange resin on the surface of the obtained electrolyte membrane to form the first catalyst layer, thereby to prepare a first intermediate consisting of said substrate, the electrolyte membrane and the first catalyst layer; applying a coating fluid comprising an electrode catalyst and an ion exchange resin on the surface of the second gas diffusion layer to form the second catalyst layer, thereby to prepare a second intermediate consisting of the second gas diffusion layer and the second catalyst layer; and bonding the first gas diffusion layer to the first intermediate, so that the first catalyst layer is located between the first gas diffusion layer and the electrolyte membrane, peeling said substrate from said first intermediate after bonding said first intermediate and said first gas diffusion layer, bonding said second intermediate to the electrolyte membrane so that said second catalyst layer is located between the second gas diffusion layer and the electrolyte membrane, and wherein the first gas diffusion layer comprises a gas-diffusing substrate and a first carbon layer formed on the surface of the gas-diffusing substrate by applying a coating fluid comprising a fluorinated ion exchange resin and carbon fiber having a fiber diameter of from 50 to 200 nm and a fiber length of from 1 to 50 μm, and the first gas diffusion layer and the first intermediate are bonded, so that the first carbon layer and the first catalyst layer are in contact with each other.