Structure and ionic conductivity of rapidly quenched AgI–Ag 2WO 4 superionic conductor glasses

Abstract

Silver ion conducting glasses composed of (AgI) x –(Ag 2WO 4) 1− x ( x=0.80–0.55) were prepared by a rapid melt quenching method. Their physical properties were investigated by X-ray, DSC, impedance and Ag-109 NMR measurements. The glass transition temperatures were in the range from 110°C to 187°C. The glasses show unusually high ionic conductivities of 2.5 × 10 −3 S/cm at x=0.55 and 2.3 × 10 −1 S/cm at x=0.80, which varied exponentially with increasing AgI content. Ag-109 NMR spectra also support the high mobility of silver ions in the glasses. Structures of the glasses were investigated by FTIR and W-L 1 edge XANES. From these results it is concluded that the tungsten ions are octahedrally coordinated by oxygen ions as in crystalline Ag 2WO 4 and Ag 26I 18W 4O 16, which is quite different from the structure of AgI–Ag 2MoO 4 glasses.