Defects Formation and Transportation Process Study of Mixed Conductor La1-xSrxCoO3-δ

The average valence of Co ions and the oxygen nonstochiometry of perovskite-type oxides La1-xSrxCoO3-δwere studied by meansof iodometric titration. It hasbeen found that the cobalt valence increases with the strontium content, goes through a maximum atx=0.5 and decreases with higher strontium content. At room temperature, the maximum appears atx=0.5, and it shifts tox=0.4 when the temperature increases. Theelectrical conductivity and relaxationstrengthof internal friction peak at 330K shows the similar variation pattern. For the same Sr dopant content, the average valence of Co decreases with the temperature.