Evaluation of GdSrCoO_(4+δ) intergrowth oxides as cathode materials for intermediate-temperature solid oxide fuel cells

摘要

This paper reports on synthesis and evaluation of an intergrowth oxide, GdSrCoO_(4+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℃ to 65 S cm~(-1) at 800℃. The catalytic activities of GSCO oxides for oxygen reduction reactions are evaluated using symmetrical impregnated GdSrCoO_(4+δ)-La_(0.9)Sr_(0.1) Ga_(0.8)Mg_(0.2)O_3 (GSCO-LSGM) cathode fuel cells. The polarization resistances for such composites increase from 0.072Ω cm~2 at 650℃ to 0.55Ω cm~2 at 550℃, 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℃ and 1314 mW cm~(-2) at 650℃, respectively. These results demonstrate that GSCO is a promising cathode candidate for intermediate-temperature solid oxide fuel cells with LSGM electrolytes.