IMPROVED MEMBRANE-ELECTRODE UNITS AND FUEL CELLS HAVING A LONG SERVICE LIFE

摘要

The present invention relates to a membrane electrode unit having two gas diffusion layers, each contacted with a catalyst layer, which are separated by a polymer electrolyte membrane, wherein the polymer electrolyte membrane has an inner area which is contacted with a catalyst layer, and an outer area which is not provided on the surface of a gas diffusion layer, characterized in that the thickness of the inner area of the membrane decreases over a period of 10 minutes by at least 5% at a pressure of 5 N/mm² and the thickness of the membrane in the outer area is greater than the thickness of the inner area of the membrane.