Investigation of SmBaCuCoO5+δ double-perovskite as cathode for proton-conducting solid oxide fuel cells

SmBaCuCoO5+δ, a double-perovskite oxide, was synthesized by the modified Pechini method and developed as cathode material for proton-conducting solid oxide fuel cells. The SmBaCuCoO5+δ powders calcined at 800 °C, show the double-perovskite structure in powder XRD pattern. SmBaCuCoO5+δ has a more suitable thermal expansion coefficient than SmBaCo2O5+δ for BaCe0.7Zr0.1Y0.2O3−δ electrolyte-based solid oxide fuel cells. The single cell was tested with humidified hydrogen (∼3% H2O) as the fuel and static air as the oxidant. The performance of the cell was characterized by DC Electronic Load and AC impedance spectroscopy. The peak power densities reached 355–86 mW cm−2 in the range of 700–550 °C and the interfacial polarization resistance decreased with increasing operation temperature, from 3.1 Ω cm2 at 550 °C to 0.22 Ω cm2 at 700 °C. The high power density and low polarization demonstrate that SmBaCuCoO5+δ is a potential candidate for proton-conducting solid oxide fuel cells.