Investigation of SmBaCuCoO_5+δ double-perovskite as cathode for proton-conducting solid oxide fuel cells

SmBaCuCoO_5+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 SmBaCuCoO_5+δ powders calcined at 800 °C, show the double-perovskite structure in powder XRD pattern. SmBaCuCoO_5+δ has a more suitable thermal expansion coefficient than SmBaCo₂O_5+δ for BaCe _0.7Zr_0.1Y_0.2O_3-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 SmBaCuCoO _5+δ is a potential candidate for proton-conducting solid oxide fuel cells.