Abstract: A solid polymer electrolyte fuel cell including a solid polymer electrolyte membrane, an anode side electrocatalyst electrode provided at one side of the polymer electrolyte membrane and an cathode side electrocatalyst electrode provided at the other side of the polymer, a membrane-like electrocatalyst layer permitting mass transfer therethrough provided at a boundary surface of an electrocatalyst layer for an oxygen reduction reaction in the polymer electrolyte membrane in the cathode side electrocatalyst electrode, and the membrane-like electrocatalyst layer including an electrocatalyst substance. A power generation efficiency can be remarkably improved with a simply structure and advantageous cost performance in the field of a solid polymer electrolyte fuel cell.

Abstract: A polymer electrolyte fuel cell comprising a polymer electrolyte membrane, an anode catalytic electrode disposed at one side of the polymer electrolyte membrane, a fuel gas being supplied to the anode catalytic electrode, a cathode electrode disposed at another side of the polymer electrolyte, an oxidation gas being supplied to the cathode catalytic electrode, control means for controlling a reduction amount of water from the cathode electrode accompanying with the oxidation gas to a sum of a water amount increased at the cathode electrode transported from the anode electrode through the polymer electrolyte membrane during a redox reaction of the fuel cell and a water amount produced by an oxidation reaction in the cathode electrode. A compact fuel cell system with a high cell performance can be accomplished.