A highly efficient bismuth substitution induced A-site ordered layered perovskite electrode for symmetrical solid oxide fuel cells

Abstract

The rational design of identical electrode materials with high activity and stability is still a big challenge for developing symmetrical solid oxide fuel cells (SSOFCs). In this study, bismuth-doped Pr_0.5Ba_0.5MnO_3−δ (Pr_0.4Bi_0.1Ba_0.5MnO_3−δ, Bi-PBM) is proposed and investigated as a symmetrical electrode material for SSOFCs. A-Site ordered Pr_0.8Bi_0.2BaMn₂O_5+δ (L-Bi-PBM) is obtained by in situ annealing disordered Bi-PBM at 800 °C for 10 h. With the substitution of bismuth in Pr-sites, the catalytic activity towards oxygen reduction and fuel oxidation can be enhanced significantly owing to the improved oxygen diffusion efficiency. The cathode polarization resistance is decreased from 0.13 to 0.11 Ω cm² at 850 °C, while the anode polarization resistance is reduced from 0.67 to 0.37 Ω cm². The fabricated L-Bi-PBM symmetrical single cell exhibits a maximum power density of 926.7 mW cm⁻² and 431.7 mW cm⁻² at 850 °C in wet hydrogen and methane, respectively. In addition, the L-Bi-PBM single cell shows a stable power output both in wet hydrogen and methane, indicating that the proposed L-Bi-PBM is a promising electrode material for SSOFCs.