Membrane electrode assembly, and solid polymer fuel cell using the assembly

摘要

Disclosed is a membrane electrode assembly obtained by bonding electrodes to both surfaces of a solid polymer electrolyte membrane suitably for use in a solid polymer fuel cell. In order to maintain not only the solid polymer electrolyte but also the electrode in appropriate wet states, the catalyst layer of the assembly contains a metalloxane polymer in the intra-catalyst-layer electrolyte including an electrode catalyst preferably in an amount of 0.5 to 50 wt % of the total weight of the intra-catalyst-layer electrolyte and the metalloxane polymer contained therein exclusive of the electrode catalyst. It is also preferred that a metalloxane polymer be included in the solid polymer electrolyte membrane in an amount of 0.5 to 50 wt % of the total weight of the solid polymer electrolyte membrane and the metalloxane polymer contained therein. The membrane electrode assembly constituted as above may be obtained by bonding the catalyst layer containing metalloxane monomer to the solid polymer electrolyte membrane by hot-pressing or the like. Here, it is preferred that the gas-phase surface of the intra-catalyst-layer electrolyte be covered with a gas-permeable, water repellent layer. The water-repellent layer may be formed by various methods such as applying hydrophobic metalloxane precursor, followed by polycondensation.