| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for suppressing the decrease in the proton conductivity of a polymer electrolyte membrane for fuel cells.SOLUTION: According to such a method, a hydrocarbon based polymer electrolyte membrane to be disposed between an anode and a cathode is arranged. The hydrocarbon based polymer electrolyte membrane comprises: an anode-side layer; and a cathode-side layer. In the hydrocarbon based polymer electrolyte membrane, an outermost layer of at least one of the anode-side layer and the cathode-side layer is larger than a layer adjacent thereto in coefficient of water absorption, and preferably the difference between the anode-side outermost layer and the adjacent layer in coefficient of water absorption is 5% or more. Further, the hydrocarbon based polymer electrolyte membrane is composed of a laminate having two or more layers each including an ion-exchange group-containing hydrocarbon based polymer. Still further, in the laminate, at least one outermost layer and a layer in contact thereto are layers substantially identical to each other in molecular structure and each including an ion-exchange group-containing hydrocarbon based polymer. |
