PROTON CONDUCTIVE MEMBRANE, METHOD FOR PRODUCING SAME, AND FUEL CELL USING SAME

An object of the present invention is to provide a stable protonically-conductive membrane for fuel cell having a high reliability. Another object of the present invention is to provide a high efficiency fuel cell having a high mechanical strength which operates over an extended period of time. The protonically-conductive membrane (ionically-conductive membrane) of the present invention is formed by a mesoporous thin film comprising as a main component a crosslinked structure having a metal-oxygen skeleton having an acid group connected to at least a part thereof and having pores (3) periodically aligned therein.