Investigation of cobalt-free cathode material Sm 0.5Sr 0.5Fe 0.8Cu 0.2O 3− δ for intermediate temperature solid oxide fuel cell

Abstract

A cobalt-free cubic perovskite oxide Sm 0.5Sr 0.5Fe 0.8Cu 0.2O 3−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 Sm 0.2Ce 0.8O 1.9(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 cm 2 at 700 °C. Laboratory-sized tri-layer cells of NiO-SDC/SDC/SSFCu were operated from 450 to 700 °C with humidified hydrogen (∼3% H 2O) as fuel and the static air as oxidant. A maximum power density of 808 mW cm 2 was obtained at 700 °C for the single cell.