A cobalt-free layered oxide as an oxygen reduction catalyst for intermediate-temperature solid oxide fuel cells

Cobalt-free layered perovskite oxide Sr4Fe6O13−δ which shows good phase stability (e.g. retain single phase between room temperature and 1050 °C in air) and low thermal expansion was evaluated as an oxygen reduction component in intermediate-temperature solid oxide fuel cells. We showed that the drawback of this layered oxide in terms of its low oxygen reduction reactivity (due to the restriction of oxygen transport in the ac plane along the layered oxide (FeO5) layer) can be circumvented by tuning the phase composition (perovskite to layered oxide phases) through an oxygen deficient calcination process. The optimum performance was attained by calcining Sr4Fe6O13−δ at 900 °C; leading to an area specific resistance (ASR) of 0.139 Ω cm2 at 700 °C.103