Effective calcium co-doping in Sm0.8Ca0.2Ba1-xCaxCo2O5+δ cathode materials for intermediate-temperature solid oxide fuel cells

Abstract

High performance and durability of electrode materials are key requirements for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Herein, a novel doubles perovskite oxides Sm0.8Ca0.2Ba1-xCaxCo2O5+δ (x=0.1 and 0.2; SCBCC) were prepared by A site calcium co-doping strategy. x=0.1 sample shows stabilized an orthorhombic structure with the space group Pmmm. Compared with parent SmBaCo2O5+δ, substitution of Ca for Sm and Ba effectively reduces the thermal expansion coefficient (TEC) (20.2 × 10−6 K−1 to 13.2 × 10−6 K−1). x=0.1 sample exhibits excellent chemical compatibility with CeO2-based electrolytes up to 1000 °C, the conductivity values reach 340–400 S cm−1 at 600–800 °C. The sample with x = 0.1 showed the best catalytic activity and carbon dioxide resistance. The area specific resistance and maximum power density of the x= 0.1 cathode are 0.022 Ω cm2 and 885 mW cm−2 at 800 °C. x = 0.1 double perovskite has good chemical compatibility and electrochemical properties while greatly reducing TEC, making this double perovskite a promising material for IT-SOFCs.