A-site alkali metal-doped SrTi0.3Fe0.7O3-δ: A highly stable symmetrical electrode material for solid oxide electrochemical cells

To addresses the limitations in electrode performance observed at temperatures <= 700 degrees C, attributed to the low oxygen surface exchange coefficient primarily caused by high Sr surface segregation, we developed an electrode performance enhancement strategy involving A-site alkali metal doping to SrTi1-xFexO3-delta (STF)-based perovskite. Here, we present the symmetrical electrode material for solid oxide electrochemical cells (SOCs), Sr0.95Mg0.05Ti0.3Fe0.7O3-delta (SMTF), demonstrating a unique combination of excellent symmetrical electrode performance and long-term stability. A-site Mg doping reduces the Sr surface segregation and improves the conductivity but also significantly enhances its electrochemical performance. At 700 degrees C, the performance of SMTF symmetric cell in both fuel cell and electrolysis modes is 1.5 times higher than that of STF. Moreover, under air atmosphere, SMTF demonstrates stable performance (>1000 h) at 1 A cm(-2), with no degradation observed after 400 h testing under humidified hydrogen conditions. Additionally, SMTF exhibits excellent CO2 tolerance in CO2-rich atmospheres.