Preparation and characterization of Ba _0.5Sr _0.5Fe _0.9Ni _0.1O _3-δ-Sm _0.2Ce _0.8O _1.9 compose cathode for proton-conducting solid oxide fuel cells

A cobalt-free Ba _0.5Sr _0.5Fe _0.9Ni _0.1O _3-δ-Sm _0.2Ce _0.8O _1.9 (BSFN-SDC) composite was employed as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs) using BaZr _0.1Ce _0.7Y _0.2O _3-δ (BZCY) as the electrolyte. The chemical compatibility between BSFN and SDC was evaluated. The XRD results showed that BSFN was chemically compatible with SDC after co-fired at 1100°C for 5 h. The thermal expansion coefficient (TEC) of BSFN-SDC, which showed a reasonably reduced value (16.08 × 10 ^-6 K ^-1), was effectively decreased due to Ce _0.8Sm _0.2O _1.9 (SDC) added. A single cell of Ni-BZCY/Ni-BZCY/ BZCY/BSFN-SDC with a 25-μm-thick BZCY electrolyte membrane exhibited excellent power densities as high as 361.8 mW cm ^-2 at 700°C with a low polarization resistance of 0.174 Ω cm ². The excellent performance implied that the cobalt-free BSFN-SDC composite was a promising alternative cathode for H-SOFCs.