The effects of counter cation on oxide ion conductivity: In the case of Sr-doped LaAlO_3 perovskite

摘要

Many research activities on the solid-state oxide fuel cell (SOFC) have been performed for production of electronic energy without fossil fuel. To design the efficient SOFC electrolyte, we should clarify the detailed mechanism on oxide ion conduction. LaAlO_3 perovskite has been much expected as the electrolyte material. It is known that strontium doping at lanthanum site lowers the activation energy for the oxide ion conduction. In this study, we have investigated the mechanism of the activation energy decrease in strontium-doped LaAlO_3 by the cluster model calculations based on hybrid density functional theory. It was concluded that the ionic and covalent bonds between counter cation and conductive oxide ion is responsible for the activation energy change.