Preparation and Properties of SOFC Double Perovskite Anode Sr₂Fe_1.5−xMn_xMo_0.5O_6−δ

Sr₂Fe_1.5−xMn_xMo_0.5O_6−δ (x = 0, 0.1, 0.2, 0.3, 0.4) (SFM_xM) anode materials were prepared by using a sol-gel method. The samples were characterized by using XRD, SEM, electrochemical test and other methods, in order to screen out anode materials with high catalytic activity and high electrical conductivity. XRD results revealed that the samples are all of double perovskite structure without the presence of secondary phases. With increasing doping content of Mn, the XRD diffraction peaks were split, indicating the occurrence of cubic to tetragonal perovskite phase transition. SEM observation showed that the GDC electrolyte is compact and both the anode and cathode are of three-dimensional porous structure. Using H₂ as fuel and static air as oxidant, the single cell performance was tested in the temperature range of 550‒800 ℃. The performance is optimized at the Mn doping concentration of x = 0.2. The polarization impedance of the anode is 0.015 Ω·cm² at 800 ℃ and the maximum power density of the cell reaches 192 mW·cm⁻². Therefore, b-site doping is an effective way to improve the performance of SFM materials. Specifically, SFM0.2M is a potential candidate of SOFC anode.