BaCo0.7Fe0.2Nb0.1O3−δ as cathode material for intermediate temperature solid oxide fuel cells

BaCo0.7Fe0.2Nb0.1O3−δ (BCFN) has been synthesized and characterized as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) using La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) electrolyte. X-ray diffraction results show that pure cubic BCFN perovskite phase can be obtained at 950 °C through solid state reactions of BaCO3, Co3O4, Fe2O3 and Nb2O5. The electrical conductivity of BCFN increases with the increase in oxygen partial pressure, indicating that BCFN is a p-type semiconductor. The polarization resistance of the BCFN cathode with LSGM electrolyte is only 0.06 Ω cm2 at 750 °C in air under open-circuit conditions. The overpotential at a current density of 1 A cm−2 in oxygen was only about 0.04 V at 750 °C. Peak power densities of 550, 770 and 980 mW cm−2 have been achieved on LSGM-electrolyte supported single cells with the configuration of Ni-Gd0.1Ce0.9O1.95|La0.4Ce0.6O2|LSGM|BCFN at 700, 750 and 800 °C, respectively. These results indicate that BCFN is a very promising cathode candidate for IT-SOFCs with LSGM electrolyte.

► BaCo0.7Fe0.2Nb0.1O3−δ (BCFN) has been evaluated as cathode for IT-SOFCs with LSGM electrolyte. ► Pure cubic BCFN perovskite phase can be obtained at 950 °C through solid state reaction approach. ► Overpotential of BCFN at a current density of 1 A cm−2 in oxygen was only about 0.04 V at 750 °C. ► 980 mW cm−2 was achieved on LSGM-electrolyte supported cells with BCFN cathode at 800 °C. ► BCFN is a very promising cathode candidate for IT-SOFCs with LSGM electrolyte.