Defect chemistry and transportation within La1.7Ba1.3In2O6.85 mixed ionic-electronic conducting membrane: Towards the application of solid oxide fuel cells

Abstract

La1.7Ba1.3In2O6.85, as a representative material belonging to La2BaIn2O7-based family, is a novel and promising electrolyte material for solid oxide fuel cells (SOFCs). However, due to the co-existence of various mobile charged defects including oxygen vacancy, proton, and electron-hole, the conduction properties and behaviors of La1.7Ba1.3In2O6.85 are complex and not fully understood. In this work, we systematically explore La1.7Ba1.3In2O6.85 with a focus on defect chemistry and transportation. A theoretical model is built to analyze the experimentally measured conductivities of La1.7Ba1.3In2O6.85 at varying temperatures and oxygen partial pressures. Subsequently, the conduction properties and behaviors of La1.7Ba1.3In2O6.85 membrane at open circuit conditions and operation conditions are investigated thoroughly for the first time. Our findings reveal that in reducing and humidified atmospheres, La1.7Ba1.3In2O6.85 behaves as a dual-ion conducting oxide, with oxygen-ionic transport numbers exceeding 0.7. Our work can provide a new and overall understanding of the La2BaIn2O7-based material for SOFCs’ application.