Membrane-electrode assembly and polymer electrolyte fuel cell

Abstract

A membrane-electrode assembly for polymer electrolyte fuel cells comprising a polymer electrolyte membrane and two gas diffusion electrodes being bonded to the membrane so that the membrane can be between them, in which assembly each gas diffusion electrode is comprised of an electrode catalyst layer and a gas diffusion layer, intermediate layer(s) being an ion conductor is/are arranged between the electrode catalyst layer(s) and the membrane, the ion conductor mainly comprises a block copolymer comprising a polymer block (A) having ion-conductive groups and a polymer block (B) having no ion-conductive group, both blocks phase-separate from each other, (A) forms a continuous phase, and the contact part(s) of the intermediate layer(s) with the polymer electrolyte membrane and the contact part(s) of the intermediate layer(s) with the electrode catalyst layer(s) are comprised of polymer block (A) having ion-conductive groups; and a polymer electrolyte fuel cell wherein the assembly is used. By the invention, a membrane-electrode assembly and a fuel cell are provided which are economical, environment-friendly, good in moldability, and small in interface resistance and excellent in power generation efficiency.