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 Sr2FeTiO6−δ (SFT) has been developed for intermediate-temperature solid oxide fuel cells (IT-SOFCs) using Ce0.8Sm0.2O1.9 (SDC) electrolyte. The reactivity tests show that the SFT electrode is chemically compatible with the SDC electrolyte at 1100°C for 10h. The electrical conductivity of SFT sample reaches 2.83–2.33Scm−1 the temperature range of 600–800°C. The thermal expansion coefficient of the SFT sample is 16.8×10−6K−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 441mWcm−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 0.204Ωcm2 at 800, 750 and 700°C, respectively. Maximum power density of 335mWcm−2 has been achieved for a symmetrical single cell with the configuration of SFT/SDC/SFT at 800°C with wet H2 as fuel and ambient air as oxidant. These results indicate that SFT is a very promising electrode candidate for IT-SOFCs with SDC electrolyte.