Evaluation of double perovskite Sr2FeTiO6−δ as potential cathode or anode materials for intermediate-temperature solid oxide fuel cells

Abstract A “cobalt-free” double perovskite electrode material with stoichiometric composition Sr 2 FeTiO 6− δ (SFT) has been developed for intermediate-temperature solid oxide fuel cells (IT-SOFCs) using Ce 0.8 Sm 0.2 O 1.9 (SDC) electrolyte. The reactivity tests show that the SFT electrode is chemically compatible with the SDC electrolyte at 1100 °C for 10 h. The electrical conductivity of SFT sample reaches 2.83–2.33 S cm −1 the temperature range of 600–800 °C. The thermal expansion coefficient of the SFT sample is 16.8×10 −6 K −1 the temperature range of 30–1000 °C in air, which is lower than that of most of the reported Co-based electrodes. Using NiO–SDC as anode, SFT as cathode, and SDC as supported electrolyte, the single cell exhibits maximum power density of 441 mW cm −2 at 800 °C. The area specific resistances of the SFT electrode on SDC electrolyte calcined at 1000 °C were found to be 0.051, 0.094 and 0.204 Ω cm 2 at 800, 750 and 700 °C, respectively. Maximum power density of 335 mW cm −2 has been achieved for a symmetrical single cell with the configuration of SFT/SDC/SFT at 800 °C with wet H 2 as fuel and ambient air as oxidant. These results indicate that SFT is a very promising electrode candidate for IT-SOFCs with SDC electrolyte.