Patent ID: 8263286

Claim:
A membrane-electrode assembly, comprising a polymer electrolyte membrane and two gas diffusion electrodes bonded to the polymer electrolyte membrane so that the polymer electrolyte membrane is between the two gas diffusion electrodes, in which assembly each gas diffusion electrode comprises an electrode catalyst layer and a gas diffusion layer, wherein: at least one intermediate layer, being an ion conductor, is arranged between at least one electrode catalyst layer and the polymer electrolyte membrane adjacent; the ion conductor comprises a block copolymer comprising a polymer block (A) having at least one ion-conductive group and a polymer block (B) having no ion-conductive group; polymer block (A) and polymer block (B) phase-separate from each other; polymer block (A) forms a continuous phase; and at least one contact part of the at least one intermediate layer with the polymer electrolyte membrane and the at least one contact part of the at least one intermediate layer with the electrode catalyst layer comprise polymer block (A).