Enhanced ORR activity of A-site deficiency engineered BaCo0·4Fe0·4Zr0·1Y0·1O3-δ cathode in practical YSZ fuel cells

Abstract Solid oxide fuel cell (SOFC) is becoming more and more attractive because of enormous progress, like high-performance and durable BaCo0·4Fe0·4Zr0·1Y0·1O3-δ (BCFZY) perovskite cathode at intermediate-to-low temperatures. Here, we propose an A-site deficient strategy to further enhance the oxygen reduction reaction (ORR) activity of BCFZY perovskite cathode for intermediate-temperature SOFC based upon commercial 8 mol% yttria-stabilized zirconia (YSZ) electrolyte. Both A-site deficient and stoichiometric BCFZY show a cubic perovskite structure without any impurity phases from room temperature to 1000 °C in air. A ten percent A-site deficiency in BCFZY cathode can dramatically reduce the area specific resistances (ARSs) from 0.73 Ω · cm2 to 0.13 Ω · cm2 at 650 °C in air, by a factor of 5.6 as compared with the stoichiometric BCFZY cathode. The YSZ-based SOFC with A-site deficient Ba0·9Co0·4Fe0·4Zr0·1Y0·1O3-δ cathode showed the maximum power density of 730 mW · cm−2 at 800 °C increased to more than 2 times in comparison with stoichiometric BCFZY and the long-term stability of more than 50 hours without any degradation. The results have indicated that the introduction of A-site deficiency can dramatically improve the ORR activity of BCFZY, showing great promise as potential cathode materials in practical YSZ-based fuel cells.