A redox−reversible perovskite electrode for CeO2− and LaGaO3−based symmetric solid oxide fuel cells

Perovskite oxide SrFe0.9Mo0.1O3−δ (SFM) was evaluated as the electrode for symmetric solid oxide fuel cells (S–SOFCs) with Sm0.2Ce0.8O2−δ (SDC) and La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolytes. Under reducing conditions at 800 °C, the SFM was reduced to be a multi-phase composite consisting of the single perovskite phase, Ruddlesden–Popper (RP) layered perovskite phase, and Fe0 phase. After reoxidation at 800 °C in air, this multi−phase system was again transformed into the parent perovskite phase again, indicating good redox reversibility of the SFM. At 700 °C, polarisation resistances of the SFM used as the cathodes on the LSGM and SDC electrolytes were 0.28 and 0.14 Ω cm2, respectively, in air. Using H2 as a fuel, the LSGM and SDC supported S–SOFCs with the SFM symmetric electrodes showed the peak power outputs of 253 and 269 mW cm−2, respectively, at 700 °C. Finally, the good long-term stability and redox-cycling stability of the S–SOFCs further demonstrate the potential of the SFM as the symmetric electrode.