Ionic diffusion coefficients in AgI-Ag oxysalt high-conductivity glasses

The diffusion of Ag +, Cu +, Na +, K + and Rb + has been studied in the vitreous superionic conductor 4AgI:Ag 2WO 4. Throughout the investigated temperature range DAg and DCu were found to be very close to each other, both showing an activation energy of 4.2-4.3 kcal/mole, i.e. substantially coincident with that obtained from conductivity determinations. The estimated haven ratio, HR=0.26, is independent of T and suggests a cooperative mechanism of transport. Although very reproducible, the values of the diffusion coefficients for the alkali ions at room temperature should be regarded with some caution since they are unexpectedly one order of magnitude larger than DAg