Evaluation of GdSrCoO4+δ intergrowth oxides as cathode materials for intermediate-temperature solid oxide fuel cells

Abstract

This paper reports on synthesis and evaluation of an intergrowth oxide, GdSrCoO4+δ (GSCO), as a new cathode material for intermediate-temperature solid oxide fuel cells. The oxygen content and the thermal expansion coefficient of GSCO oxide powders were measured. The GSCO oxide shows a semi-conducting behaviour in air with conductivities increasing from 16 S cm−1 at 500°C to 65 S cm−1 at 800°C. The catalytic activities of GSCO oxides for oxygen reduction reactions are evaluated using symmetrical impregnated GdSrCoO4+δ–La0.9Sr0.1Ga0.8Mg0.2O3 (GSCO-LSGM) cathode fuel cells. The polarization resistances for such composites increase from 0.072Ω cm2 at 650°C to 0.55Ω cm2 at 550°C. Furthermore, thin LSGM electrolyte supported fuel cells with impregnated Ni anodes and GSCO cathodes exibit high power densities at reduced temperatures, e.g., 782 mW cm−2 at 550°C and 1314 mW cm−2 at 650°C, respectively. These results demonstrate that GSCO is a promising cathode candidate for intermediate-temperature solid oxide fuel cells with LSGM electrolytes.