MEMBRANE ELECTRODE ASSEMBLY FOR SOLID POLYMER FUEL CELL AND METHOD FOR PRODUCING SAME

摘要

Disclosed is a method for producing a membrane electrode assembly for solid polymer fuel cells which assembly comprises an anode and a cathode respectively having a catalyst layer and an ion exchange membrane arranged between the anode and the cathode. In this method, a step for producing at least one of the catalyst layers of the anode and cathode includes a substep for preparing a coating liquid containing a catalyst powder composed of catalyst metal particles supported by carbon supports and an ion exchange resin and another substep for forming a catalyst layer by applying the coating liquid to a base. The coating liquid is prepared by using a catalyst powder having an existence density of functional groups, namely total of OH groups and CO groups, in the surface of not more than 1.6 x 10<-3> mmol/m<2>. In this connection, the existence density is calculated using the total number of moles of OH groups and CO groups in the surface which is determined by titration and the BET specific surface area. A solid polymer fuel cell comprising a membrane electrode assembly obtained by this method is high in initial power generation performance and can maintain stable output characteristics for a long time.