Synthesis and characterization of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.1 Ni 0.1 O 3-δ cathode for intermediate-temperature solid oxide fuel cells

Abstract Perovskite Ba 0.5 Sr 0.5 Co 0.8 Fe 0.1 Ni 0.1 O 3-δ (BSCFNi) oxide is synthesized and characterized as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The X-ray diffraction (XRD) spectra show that BSCFNi is chemical compatible with La 0.9 Sr 0.1 Ga 0.83 Mg 0.17 O 2.865 (LSGM) electrolyte below 950 °C, but weak reaction is observed between BSCFNi cathode and Sm 0.2 Ce 0.8 O 1.9 (SDC) electrolyte after calcined at 950 °C for 10 h. The XPS results indicate that transition metal cations in BSCFNi sample exist two different valence states, i.e., Co 4+/3+ , Fe 4+/3+ and Ni 3+/2+ . The average thermal expansion coefficient (TEC) of BSCFNi is 18.7 × 10 −6  K −1 between 200 °C and 850 °C in air. The maximum electrical conductivity reaches 35.3 Scm −1 at 425 °C in air. The polarization resistance of BSCFNi cathode on LSGM and SDC electrolytes are 0.033 and 0.066 Ωcm 2 at 800 °C, respectively. The maximum power density of LSGM electrolyte-supported single cell with BSCFNi cathode reaches 690 mWcm −2 at 800 °C. These primarily results indicate that BSCFNi is a candidate cathode material for IT-SOFCs.