Optimizing the Copper Content in GdBa 0.5 Sr 0.5 Co 2-X Cu x O 5+δ Double Perovskites as the High Performance Oxygen Electrodes for Reversible Solid Oxide Cells

Doping with copper is studied in a series of double perovskite-type GdBa 0.5 Sr 0.5 Co 2-x Cu x O 5+δ , candidate oxygen electrode materials for reversible Solid Oxide Cells. Obtained by a sol-gel method, the material with x = 1.15, having the highest amount of the introduced Cu (lowest Co content) is selected, and systematically evaluated regarding physicochemical characteristics, as well as chemical stability with La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ and Ce 0.9 Gd 0.1 O 2-δ solid electrolytes. Promising electrochemical performance is obtained if this compound is used to manufacture oxygen electrodes, with the recorded low polarization resistance of 0.144 Ω cm 2 at 700 °C, and 0.020 Ω cm 2 at 850 °C. Also, the anode-supported laboratory cell is found to deliver over 725 mW cm -2 power density at 850 °C, and shows good performance in the electrolyzer mode.