The proton conductivity of hydrated compounds (ZrO2•nH2O, SnO2•nH2O, Ce(HPO4)2•nH2O) was investigated at 25 to 150C under saturated water-vapor pressures. They exhibited proton conductivities which were of the order of 0.01S/cm at 150C. The activation energies for conduction ranged from 0.16 to 0.19eV; thus suggesting the operation of a surface-adsorbed water mechanism.

Proton Conductivity of Some Hydrated Compounds at Intermediate Temperatures of up to 150C under High Water Vapor Pressures. Y.M.Li, M.Hibino, M.Miyayama, T.Kudo: Electrochemistry, 2001, 69[1], 2-5