Proton conduction in glasses prepared via sol–gel and melting techniques

Phosphosilicate glasses were prepared using both sol–gel and conventional melting methods, and proton conductivity of these glasses was investigated. Glasses prepared by sol–gel method are porous, and proton conductivity increases significantly by absorption of water. The pore structure, especially pore size, is a crucial factor in order to obtain high proton conductivity in wide temperature/humidity ranges. On the other hand, in the case of glasses prepared via conventional melting method, proton incorporation into the glasses as well as decreasing alkali cation conductivity by utilizing the mixed-alkali effect are indispensable. Proton conduction mechanisms in these glasses are discussed.