Fast proton-conducting glassy plates and films which had room-temperature conductivities of about 0.01S/cm were prepared from the alkali-free phosphate system by using sol-gel processing. It was found that the solid amorphous super-protonic conductors were chemically stable and were non-hygroscopic in ambient air; even though they contained molecular water.

Y.Abe, G.Li, M.Nogami, T.Kasuga, L.L.Hench: Journal of the Electrochemical Society, 1996, 143[1], 144-7