Novel BaBi0.05Co0.8Nb0.15O3−δ perovskite oxide as cathode material for intermediate-temperature solid oxide fuel cells

Abstract A cubic perovskite oxide, BaBi 0.05 Co 0.8 Nb 0.15 O 3−δ (BBCN) is investigated as a cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). XRD results show that BBCN cathode is chemically compatible with the electrolyte Sm 0.2 Ce 0.8 O 1.9 (SDC) at 950 °C for 5 h. The XPS results show that the Co 3+ /Co 4+ , Nb 5+ , Bi 3+ and Ba 2+ species exist in the BBCN sample. The thermal expansion coefficient (TEC) of the BBCN sample is 19.60 × 10 −6  K −1 between 30 and 850 °C in air. The R p of BBCN cathode on SDC electrolyte is 0.047, 0.077 and 0.136 Ω cm 2 at 800, 750, 700 °C, respectively. A maximum power density of 507 mW cm −2 is obtained at 800 °C for single-cell with 300 μm thick SDC electrolyte and BBCN cathode. The results of this study demonstrate that BBCN can be a promising cathode material for IT-SOFCs.