LAUSR

Abstract Cobalt–free BaFe0.9Nb0.1O3–δ (BFNb) was investigated as a cathode material for intermediate–temperature solid oxide fuel cell (IT–SOFC). XRD refinements favour the co–existence of at least cubic and tetragonal phases in the BFNb sintered at 1000 or 1100 oC, in which the content of the cubic phase decreased with increasing sintering temperature. Because of the presence of BaFe2O4 impurity in the 1100 oC prepared sample, the temperature of 1000 oC was preferred for the final sample preparation. At IT region (600–800 oC), the electrical conductivity of the BFNb sample was 2.5–1.8 S cm–1, and the average thermal expansion coefficient (TEC) was 18.3 × 10–6 K–1. The polarization resistance of the BFNb cathode on Gd0.1Ce0.9O1.95 (GDC) electrolyte achieved 0.102 Ω cm2 at 700 oC. For a single cell with BFNb cathode and 300–μm–thick GDC electrolyte, a peak power density of 397 mW cm–2 was attained at 700 oC, and a 30–h long–term testing demonstrates the good stability of the BFNb cathode under a real SOFC operating condition.