Investigation of cobalt-free cathode material Sm0.5Sr0.5Fe0.8Cu0.2O3−δ for intermediate temperature solid oxide fuel cell

A cobalt-free cubic perovskite oxide Sm0.5Sr0.5Fe0.8Cu0.2O3−δ (SSFCu) was investigated as a novel cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The thermal expansion coefficient (TEC) of SSFCu was close to that of Sm0.2Ce0.8O1.9(SDC) electrolyte and the electrical conductivity of SSFCu sample reached 72–82 S cm−1 in the commonly operated temperatures of IT-SOFCs (400–600 °C). Symmetrical electrochemical cell with the configuration of SSFCu/SDC/SSFCu was applied for the impedance study and area specific resistance (ASR) of SSFCu cathode material was as low as 0.085 Ω cm2 at 700 °C. Laboratory-sized tri-layer cells of NiO-SDC/SDC/SSFCu were operated from 450 to 700 °C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. A maximum power density of 808 mW cm2 was obtained at 700 °C for the single cell.