Ni-doped Sr2Fe1.5Mo0.5O6-δ as Anode Materials for Solid Oxide Fuel Cells

Abstract

10% Ni-doped Sr2Fe1.5Mo0.5O6-δ with A-site deficiency is prepared to induce in situ precipitation of B-site metals under anode conditions in solid oxide fuel cells. XRD, SEM and TEM results show that a significant amount of nano-sized Ni-Fe alloy metal phase has precipitated out from Sr1.9Fe1.4Ni0.1Mo0.5O6-δ upon reduction at 800°C in H2. The conductivity of the reduced composite reaches 29 S cm−1 at 800°C in H2. Furthermore, fuel cell performance of the composite anode Sr1.9Fe1.4Ni0.1Mo0.5O6-δ-SDC is investigated using H2 as fuel and ambient air as oxidant with La0.8Sr0.2Ga0.87Mg0.13O3 electrolyte and La0.6Sr0.4Co0.2Fe0.8O3 cathode. The cell peak power density reaches 968 mW cm−2 at 800°C and the voltage is relatively stable under a constant current load of 0.54 A cm−2. After 5 redox cycles of the anode at 800°C, the fuel cell performance doesn't suffer any degradation, indicating good redox stability of Sr1.9Fe1.4Ni0.1Mo0.5O6-δ. Peak power density of 227 mW cm−2 was also obtained when propane is used as fuel. These results indicate that a self-generated metal-ceramic composite can been successfully derived from Sr2Fe1.5Mo0.5O6-δ by compositional modifications and Sr1.9Fe1.4Ni0.1Mo0.5O6-δ is a very promising solid oxide fuel cell anode material with enhanced catalytic activity and inherited good redox stability from the parent ceramic material.