Polymer electrolyte membrane and solid polymer electrolyte fuel cell using same

A solid polymer electrolyte fuel cell equipped with a membrane electrode assembly wherein a pair of electrodes and an electrolyte membrane between the two electrodes are combined so as to form a single entity, wherein:

• the electrolyte membrane comprises a composite polymer electrolyte membrane comprising a mixture of at least two types of polymer electrolyte including a first polymer electrolyte and a second polymer electrolyte, the first polymer electrolyte comprising a sulfonated polyarylene polymer and constituting 50-95 wt % of the electrolyte membrane, and the second polymer electrolyte comprises a hydrocarbon polymer electrolyte other than the sulfonated polyarylene polymer which is the first polymer electrolyte, wherein the first polymer electrolyte and the second polymer electrolyte have different skeleton structures from each other, and
• the first polymer electrolyte comprises a sulfonated polyarylene polymer comprising an aromatic compound repeating unit with an electron-attractive group in the principal chain thereof and an aromatic compound repeating unit without an electron-attractive group in the principal chain thereof.