Preparation and Performance of Cathode Materials Ba1-xSrxCo0.7Fe0.2Nb0.1O3-δ for Intermediate-temperature Solid Oxide Fuel Cells

The Ba1-xSrxCo0.7Fe0.2Nb0.1O3-delta(x=0, 0.1, 0.2, 0.3, 0.4) oxides were synthesized by the conventional solid state reaction process and investigated as a cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). All prepared Ba1-xSrxCo0.(7)Fe(0.2)Nb(0.1)03.6(x=0-0.4) powders were sintered at 1000 degrees C. X-ray diffiaction patterns indicate that all samples have a single phase of cubic perovskite structure. The morphologies of the symmetric cell were characterized by a scanning electron microscope (SEM). The cathode exhibits fine uniform microstructure with appropriate porosity, and shows good bonding and continuous contact with the dense Ce0.85Sm0.15O1.925(SDC) electrolyte pellet. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures show that a cathode Ba1-xSrxCo0.7Fe0.2Nb0.1O3-delta exhibits the best electrochemical performance. The maximum power density of single cell with Ba1-xSrxCo0.7Fe0.2Nb0.1O3-delta jcathode, Ni0.9Cu01-SDC anode and SDC electrolyte is 155 mW/cm(2) at 6000 degrees C. The encouraging results suggest that Ba1-xSrxCo0.(7)Fe(0.2)Nb(0.1)O(3-delta)ois a very promising cathode material for IT-SOFCs.