Improving stability and electrochemical performance of Ba0.5Sr0.5Co0.2Fe0.8O3-δ electrode for symmetrical solid oxide fuel cells by Mo doping

Abstract

Abstract Ba0.5Sr0.5Co0.2Fe0.8O3-δ (BSCF) is one of the best electrode materials for fuel cells and batteries. However, the stability of BSCF electrode is a challenge for the application of symmetrical solid oxide fuel cells (SSOFCs), and its electrochemical performance is still far from desirable. Herein, we propose that Mo doping in BSCF electrode can not only improve the electrode stability and but also effectively enhance electrochemical performance in YSZ-based SSOFCs. Ba0.5Sr0.5Co0.2Fe0.7Mo0.1O3-δ (BSCFM) electrode materials and Gd0.2Ce0.8O2-δ (GDC) buffer layer materials were synthesized by a gel combustion method. The SSOFC with a configuration of BSCFM│GDC│YSZ│GDC│BSCFM was constructed by using BSCFM as the cathode and anode, GDC as the buffer layer and YSZ as the electrolyte. The results show that the as-synthesized BSCFM electrode exhibits a cubic perovskite structure, and a remarkable stability under reducing environment. By the substitution of Mo, the interface polarization resistances were decreased from 0.051 Ω cm2 to 0.035 Ω cm2 in H2 at 800 °C. Using humid H2 (3% H2O) as fuel and static air as oxidant, the output power of the single cell is as high as 418 mW/cm2, which can work stably at 700 °C for 115 h. This work demonstrates a stable SSOFC with YSZ electrolyte and BSCF-based electrode.