Double perovskite Sr2FeMo0.6Mg0.25Ga0.15O6−δ as high-performance fuel electrode for reversible solid oxide cell

B-site double perovskite Sr 2 FeMo 0.6 Mg 0.25 Ga 0.15 O 6−δ (SFMMG) is reported as a promising fuel electrode for reversible solid oxide cell. The SFMMG material shows excellent structural stability in both oxidizing and reducing atmospheres, possesses an appropriate thermal expansion coefficient , as well as excellent redox cycle stability. The result confirms that the Mg 2+ and Ga 3+ tend to occupy the B-site while some Fe ions moves to the B′-site, creating lots of Fe B – O –Fe B’ anti-site defects in the lattice. As a result, a high electrical conductivity value of 36.0 S cm −1 is obtained at 800 °C in H 2 . Besides, the SFMMG electrode exhibits good catalytic activity toward hydrogen oxidation/evolution reaction, as confirmed by the low polarization resistance of 0.237 Ω cm 2 at 800 °C in H 2 . With SFMMG as the fuel electrode, the La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ (300 μm)-supported single cell exhibits a peak power density of 1073 mW cm −2 in fuel cell mode and an electrolysis current density of 1192 mA cm −2 in electrolysis cell mode at 900 °C. In addition, the single cell shows stable performance during 100 h operation under 0.75 V at 800 °C.