Performance of double-proveskite YBa0.5Sr0.5Co2O5+δ as cathode material for intermediate-temperature solid oxide fuel cells

Double-proveskite YBa0.5Sr0.5Co2O5+δ (YBSC) was investigated as potential cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). YBSC material exhibited a good chemical compatibility with the La0.9Sr0.1Ga0.8Mg0.115Co0.085O2.85 (LSGMC) electrolyte up to 950 °C for 2 h. The substitution of Sr for Ba significantly enhanced the electrical conductivity of the YBSC sample compared to undoped YBaCo2O5+δ, and also slightly increased the thermal expansion coefficient. At 325 °C a semiconductor–metal transition was observed and the maximum electrical conductivity of YBSC was 668 S cm−1. The maximum power densities of the electrolyte-supported single cell with YBSC cathode achieved 650 and 468 mW cm−2 at 850 and 800 °C, respectively. Preliminary results suggested that YBSC could be considered as a candidate cathode material for application in IT-SOFCs.