Investigation into the effect of Fe-site substitution on the performance of Sr2Fe1.5Mo0.5O6-δ anodes for SOFCs

Ni-substituted Sr2Fe1.5-xNixMo0.5O6-delta (SFNM) materials have been investigated as anode catalysts for intermediate temperature solid oxide fuel cells. Reduced samples (x = 0.05 and 0.1) maintained the initial perovskite structure after reduction in H-2, while metallic nickel particles were detected on the grain surface for x = 0.2 and 0.3 using transmission electron microscopy. Temperature programmed reduction results indicate that the stable temperature for SFNM samples under reduction conditions decreases with Ni content. In addition, X-ray photoelectron spectroscopy analysis suggests that the incorporation of Ni affects the conductivity of SFNM through changing the ratios of Fe3+/Fe2+ and Mo6+/Mo5+center dot Sr2Fe1.4Ni0.1Mo0.5O6-delta shows the highest electrical conductivity of 20.6 S cm(-1) at 800 degrees C in H2. The performance of this anode was further tested with electrolyte-supported cells, giving 380 mW cm(-2) at 750 degrees C in H-2, hence demonstrating that Ni doping in the B-site is beneficial for Sr2Fe1.5Mo0.5O6-delta anode performance.