Functional properties of La1–xBaxFeO3–δ as symmetrical electrodes for protonic ceramic electrochemical cells

To create highly efficient solid oxide fuel cells with a symmetrical configuration, it is necessary to develop suitable functional materials whose properties under oxidizing and reducing conditions will satisfy simultaneously the requirements for both fuel and oxygen electrodes. In the present work, the La1–xBaxFeO3–δ (x = 0.4, 0.5, 0.6) materials were obtained and investigated as symmetrical electrodes for proton-conducting electrochemical cells based on a BaCe0.7Zr0.1Y0.1Yb0.1O3–δ electrolyte. For the first time, the La1–xBaxFeO3–δ materials were comprehensively investigated in terms of electrical conductivity, thermomechanical and electrochemical properties in both oxidizing and reducing atmospheres. It is found experimentally that La0.6Ba0.4FeO3–δ demonstrates the highest electrical conductivity, lowest polarization resistances and acceptable thermal expansion behavior, which allows these materials to be used as oxygen electrodes. However, for the successful utilization of the La1–xBaxFeO3–δ as the symmetrical electrodes, their transport properties under reducing atmospheres need to be improved.