MEMBRANE CATALYST LAYER ASSEMBLY, MEMBRANE ELECTRODE ASSEMBLY, FUEL CELL AND FUEL CELL STACK

摘要

Disclosed are a membrane catalyst layer assembly and a membrane electrode assembly which enable to surely realize a polymer electrolyte fuel cell having excellent durability wherein decomposition/deterioration of a polymer electrolyte membrane can be suppressed for a long time while sufficiently preventing deterioration of initial characteristics even when operation and stoppage of the polymer electrolyte fuel cell are repeated. Specifically disclosed is a membrane catalyst layer assembly having an anode catalyst layer, a cathode catalyst layer, and a polymer electrolyte membrane arranged between the anode catalyst layer and the cathode catalyst layer and having hydrogen ion conductivity. This membrane catalyst layer assembly is characterized in that the peripheral portion of at least one of the anode catalyst layer and the cathode catalyst layer is provided with a decreasing portion wherein mass of the electrode catalyst per unit area of the catalyst layer decreases from the inner side to the outer side.