Comparative studies of BaBi0.05Zr0.1Co0.85−xNbxO3−δ (x = 0 and 0.05) as cathodes for intermediate-temperature solid oxide fuel cells

Multi-element-doped BaBi0.05Zr0.1Co0.85–xNbxO3–δ (x = 0 or 0.05, and denoted as BBZC, BBZCN, respectively) perovskite oxides are fabricated and the phase composition, electrical conductivity, thermal expansion, and electrochemical performance are investigated. With 5% Nb substitution, BBZCN exhibits improved phase structure and a reduced thermal expansion coefficient. The BBZC and BBZCN cathodes exhibited chemical compatibility with the La0.9Sr0.1Ga0.8Mg0.2O3–δ (LSGM) electrolyte. The area-specific resistances of the BBZC and BBZCN cathodes are 0.021 and 0.023 Ω cm2 with LSGM electrolyte at 800 °C. The peak power densities of 515 and 566 mW cm–2 are obtained from single cell with BBZC and BBZCN cathodes at 800 °C, respectively. These results indicate that BBZC and BBZCN perovskite oxides will be a promising candidate as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs).