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 °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 SrTi 1-x Fe x O 3-δ (STF)-based perovskite. Here, we present the symmetrical electrode material for solid oxide electrochemical cells (SOCs), Sr 0.95 Mg 0.05 Ti 0.3 Fe 0.7 O 3-δ (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 °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 CO 2 tolerance in CO 2 -rich atmospheres. • SMTF exhibits excellent ORR and OER activity as a symmetrical electrode material. • R p of SMTF electrode at 700 °C is 1/4 of STF in the air and 1/2 of STF in H 2. • S–SOCs with SMTF electrodes achieved peak power density of 1.12 W cm−2 at 800 °C. • SMTF exhibits excellent stability in both air and H 2. • SMTF demonstrated excellent CO 2 tolerance and reversibility. [ABSTRACT FROM AUTHOR]