Perovskite SrFe_1-xTi_xO_3-δ (x < = 0.1) cathode for low temperature solid oxide fuel cell

Stable and compatible cathode materials are a key factor for realizing the low-temperature (LT, ≤600 °C) operation and practical implementations of solid oxide fuel cells (SOFCs). In this study, perovskite oxides SrFe_1-xTi_xO_3-δ (x < = 0.1), with various ratios of Ti doping, are prepared by a sol-gel method for cathode material for LT-SOFCs. The structure, morphology and thermo-gravimetric characteristics of the resultant SFT powders are investigated. It is found that the Ti is successfully doped into SrFeO_3-δ to form a single phase cubic perovskite structure and crystal structure of SFT shows better stability than SrFeO_3-δ. The dc electrical conductivity and electrochemical properties of SFT are measured and analysed by four-probe and electrochemical impedance spectra (EIS) measurements, respectively. The obtained SFT exhibits a very low polarization resistance (R_p),.01 Ωcm² at 600◦C. The SFT powders using as cathode in fuel cell devices, exhibit maximum power density of 551 mW cm⁻² with open circuit voltage (OCV) of 1.15 V at 600◦C. The good performance of the SFT cathode indicates a high rate of oxygen diffusion through the material at cathode. By enabling operation at low temperatures, SFT cathodes may result in a practical implementation of SOFCs.