Evaluation of a cobalt-free Ba0.5Sr0.5Fe0.9Nb0.1O3−δ cathode material for intermediate-temperature solid oxide fuel cells

A cobalt-free Ba0.5Sr0.5Fe0.9Nb0.1O3−δ (BSFNb) perovskite-type oxide was investigated as the cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) with Sm0.2Ce0.8O1.9 (SDC) electrolyte. XRD results showed that BSFNb cathode was chemically compatible with the electrolyte SDC up to 1,000 °C. The maximum output of anode-supported thin-film SOFC reached 503 mW cm−2 at 650 °C when employing humidified H2 as fuel and static air as oxidizer. The electrode polarization resistance was low as 0.078 Ω cm2 at 650 °C, and the activation energy of the electrode polarization resistance was 129.72 kJ mol−1. The experimental results indicated that the cobalt-free BSFNb was a promising cathode candidate for IT-SOFCs.