The effect of Zr ions upon the glass structure and proton conductivity was investigated for sol-gel derived glasses. Porous samples were prepared via the hydrolysis of PO(OCH3)3, Zr(OC4H9)4 and Si(OC2H5)4. Chemical bonding of the P5+ ions was characterized by using 31P nuclear magnetic resonance spectra. The P ions, which occurred as PO(OH)3 in ZrO2-free glass, were polymerized; with 1 or 2 bridging O ions per PO4 unit with increasing ZrO2 content. The chemical stability of the glasses was significantly increased by adding ZrO2, but the conductivity gradually decreased from 26 to 12mS/cm at room temperature in SiO2-10P2O5-7ZrO2 glass.

Proton Conductivity in Zr4+-Ion-Doped P2O5-SiO2 Porous Glasses. M.Nogami, Y.Goto, T.Kasuga: Journal of the American Ceramic Society, 2003, 86[9], 1504-7