An A-site-deficient perovskite offers high activity and stability for low-temperature solid-oxide fuel cells

Solid oxide fuel cells (SOFCs) directly convert fossil and/or renewable fuels into electricity and/or high-quality heat in an environmentally friendly way. However, high operating temperatures result in high cost and material issues, which have limited the commercialization of SOFCs. To lower their operating temperatures, highly active and stable cathodes are required to maintain a reasonable power output. Here, we report a layer-structured A-site deficient perovskite Sr_0.95Nb_0.1Co_0.9O _3-δ (SNC0.95) prepared by solid-state reactions that shows not only high activity towards the oxygen reduction reaction (ORR) at operating temperatures below 600 °C, but also offers excellent structural stability and compatibility, and improved CO₂ resistivity. An anode-supported fuel cell with SNC0.95 cathode delivers a peak power density as high as 1016mW cm^-2 with an electrode-area-specific resistance of 0.052Ω cm² at 500 °C. A site to be seen: The perovskite Sr _0.95Nb_0.1Co_0.9O_3-δ (SNC0.95) with A-site deficiencies shows high activity towards the oxygen reduction reaction (ORR) at low operating temperatures due to its large oxygen vacancy concentration and high electrical conductivity. Moreover, SNC0.95 shows excellent structural stability and chemical compatibility‥ The CO₂ resistivity is also improved. These merits show that SNC0.95 is a promising cathode material for low-temperature solid oxide fuel cells.