Study on Sm1.8Ce0.2CuO4–Ce0.9Gd0.1O1.95 composite cathode materials for intermediate temperature solid oxide fuel cell

Sm1.8Ce0.2CuO4–xCe0.9Gd0.1O1.95 (SCC–xCGO, x = 0–12 vol.%) composite cathodes supported on Ce0.9Gd0.1O1.95 (CGO) electrolyte are studied for applications in IT-SOFCs. Results show that Sm1.8Ce0.2CuO4 material is chemically compatible with Ce0.9Gd0.1O1.95 at 1000 °C. The composite electrode exhibits optimum microstructure and forms good contact with the electrolyte after sintering at 1000 °C for 4 h. The polarization resistance (Rp) reduces to the minimum value of 0.17 Ω cm2 at 750 °C in air for SCC–CGO06 composite cathode. The relationship between Rp and oxygen partial pressure indicates that the reaction rate-limiting step is the surface diffusion of the dissociative adsorbed oxygen on the composite cathode.

► SCC material exhibits good chemical compatibility with CGO at 1000 °C.
► The optimum composite SCC–CGO06 gives the lowest ASR of 0.17 Ω cm2 at 750 °C in air.
► The rate-limiting step for oxygen reduction is surface diffusion of the dissociative adsorbed oxygen.