US Patent 7781535 Proton conductor

An acidic group-containing polymer which has an acidic group such as sulfonic acid group, phosphoric acid group, and phosphonic acid group, and a proton acceptor which has a boiling point at 1 atmosphere higher than 100° C. and which functions as a medium for conducting proton dissociated from the acidic group are retained in pores of a porous member. Preferred examples of the proton acceptor include a salt structure composed of an anion and a cation derived from a basic organic compound, a basic organic compound, and a dissociation-facilitating polymer which facilitates dissociation of proton. Any one of the acidic group-containing polymer and the proton acceptor may be retained first, or both may be retained simultaneously.