Synthesis and application of mixed conductive and oxygen-permeable materials based on BaFeO3-δ

Abstract

Cobalt-free perovskite oxide BaFeo3-δ (BFO) exists in mixtures with various phase structures and exhibits poor oxygen ion conductivity, thereby limiting its application as a cathode material in solid oxide fuel cells (SOFC). In this study, the stabilization of a single cubic phase structure of BFO through doping with Gd at the A-site or Cu at the B-site and the lowest temperature required for the synthesis of such a structure are investigated. A large fraction of adsorbed oxygen atoms and a low valence state of Fe are found in BaFe0.9Cu0.1O3-δ, resulting in improved performance. Furthermore, the ideal sintering temperatures for Ba0.9Gd0.1FeO3-δ cathode and BaFe0.9Cu0.1O3-δ cathode are 900 °C and 850 °C, respectively. At 700 °C, the polarization resistance of the BaFe0.9Cu0.1O3-δ cathode is 0.439 Ω·cm2 and that of the Ba0.9Gd0.1FeO3-δ cathode is 0.545 Ω·cm2.