Performance of double-proveskite YBa 0.5Sr 0.5Co 2O 5+δ as cathode material for intermediate-temperature solid oxide fuel cells

Abstract

Double-proveskite YBa 0.5Sr 0.5Co 2O 5+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 La 0.9Sr 0.1Ga 0.8Mg 0.115Co 0.085O 2.85 (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 YBaCo 2O 5+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.