Ionic Conductivity of Li2 O  ‐ Based Mixed Oxides and the Effects of Moisture and LiOH on Their Electrical and Structural Properties

Abstract

Thermal, structural, and electrical measurements on polycrystalline and certain mixed oxides [, , , and mixtures] indicate that is produced within these materials on exposure to a moist environment. The presence of produces an endothermic reaction at ∼400°C and a large increase in ionic conductivity above ∼400°C [ at 500°C]. These features are absent under dry conditions (no ). In the dry state, the ionic conductivity varies nearly exponentially with temperature (activation energies of ∼0.5–1.0 eV) and has values ranging from 10−4 to 10−3 (Ω‐cm) −1 at 500°C. All of these materials, except possibly for the Y‐containing compounds, appear to have common ionic conductivity characteristics. The electrical and structural properties of the compounds are reproducible on cycling between wet (containing ) and dry (no ) conditions. This does not appear to be the case for the other materials. There is a significant (1–50%) electronic contribution to the conductivity in these materials.