Performance of Co-doped Sr1.9FeNbO6−δ as a symmetrical electrode for solid oxide cells

The in situ exsolution of nanoparticles from perovskite oxides has garnered significant research attention and has been proven to be an effective approach for obtaining high-performance electrode materials for solid oxide cells. In this study, we synthesized a series of double perovskites Sr1.9FeNb1−xCoxO6−δ (x = 0, 0.3, 0.4, 0.5; named as SFN, SFNC03, SFNC04, SFNC05, respectively) by solid state method as electrode materials for symmetrical solid oxide fuel cells and symmetrical solid oxide electrolysis cells. At 800 °C, the impedance of SFNC05 in air and hydrogen atmospheres reached 0.025 and 0.21 Ω cm2, respectively. The output performance of the fuel cell with SFNC05 symmetrical electrode reached 806, 687, and 300 mW cm−2 using hydrogen, methanol and propane as fuels, respectively, at 800 °C. The fuel cell also showed good output performance stability over 100 h in methanol at 700 °C. In electrolysis cell mode, the current densities are −1.54 and −1.55 A cm−2 at 2 V for electrolysis CO2 and at 1.3 V for electrolysis seawater, respectively. The output performance does not degrade significantly for electrolysis CO2 and seawater during 200 h stability test.