Non-Arrhenius ionic conductivity in optimized fast ion conducting glasses: application of the Drude model to ion–ion scattering

Abstract New measurements have been made of a new series of AgI-doped Ag2S+B2S3+SiS2 FIC glasses that exhibit a dramatic non-Arrhenius temperature dependence of the conductivity. These new measurements have extended our previous measurements of these glasses to high temperature and where the non-Arrhenius behavior becomes even more pronounced. The decrease in the conductivity amounts to approximately two orders of magnitude at the highest temperatures for the highest conductivity glasses. The non-Arrhenius behavior increases with increasing AgI concentration to the point that at highest temperature, the conductivity of the glass with highest AgI fraction is only marginally more conducting that the glass without any AgI dopant. A new model of the ionic dynamics in glass has been proposed to account for the non-Arrhenius conductivity in these glasses. The Drude scattering model of classically behaving particles was applied to the conductivity of these glasses. While this zeroth order model is not able to correctly predict the temperature dependence over the full temperature range, from Arrhenius at low temperature to strongly non-Arrhenius at elevated temperature, it does correctly predict the maximum conductivity that these glasses are tending toward, ∼1 ( Ω cm)−1, and correctly predicts the temperature range where ion scattering processes become strong enough to produce the non-Arrhenius behavior seen for these glasses.