A-site bismuth doping, a new strategy to improve the electrocatalytic performances of lanthanum chromate anodes for solid oxide fuel cells

Abstract

A new strategy is proposed to improve the electrocatalytic performances of LaCrO3-based perovskites. A-site doping bismuth promotes the anode performances even higher than those reported for B-site doping Pd and Ru. For example, at 800 °C, 10 % bismuth doping reduces interfacial polarization resistance from 0.80 to 0.32 Ω cm2 and increases peak power density by ∼40 % to 0.55 W cm–2 in hydrogen. In addition, bismuth doping decreases the interfacial polarization resistance by 74 % in air. Consequently, bismuth doping improves peak power density by up to 80 % at 800 °C for symmetrical structured single cells. The doped material is stable in both air and reducing atmospheres such as in hydrogen at 850 °C for 100 h. The doped bismuth presents a sub-oxidation state, which elevates the average valence states of Cr and Fe, and increases the electronic conductivities and concentrations of surface oxygen species in both air and hydrogen atmospheres.