Surface oxygen defect engineering to enhance La0.5Sr0.5Fe0.9Mo0.1O3-δ electrochemical performance for reversible symmetric solid oxide cells

Perovskite oxide-based materials are promising electrode materials for reversible symmetric solid oxide cells (RSSOCs) as they exhibit good catalytic activity and stability in oxidizing and reducing atmospheres. In this study, A-site deficient (La0.5Sr0.5)0.95Fe0.9Mo0.1O3-δ (95LSFMo) is synthesized as an electrode material for RSSOCs. The A-site defect in La0.5Sr0.5Fe0.9Mo0.1O3-δ increases the surface oxygen vacancy concentration, promoting the transport of oxygen ions and enhancing the catalytic activities of oxygen reduction (ORR) and hydrogen oxidization reaction (HOR). 95LSFMo|LSGM|95LSFMo symmetric cell achieves a maximum power density (MPD) of 1.14 W cm−2 at 850 °C. Furthermore, the adsorption and reduction of H2O is also improved. In 50 %H2O-H2, 95LSFMo cell shows a current density of −1.71 A cm−2 at 850 °C and 1.3 V in electrolysis mode and a peak power density of 0.82 W cm−2 in fuel cell mode. The corresponding hydrogen production rate reaches 714.78 ml cm-2h−1. Moreover, the 95LSFMo cell exhibits good reversibility as well as SOEC stability.