Stable, Low Polarization Resistance Solid Oxide Fuel Cell Anodes: La_1–xSr_xCr_1–xFe_xO_3-δ (x = 0.2–0.67)

The perovskite series, La 1– x Sr x Cr 1– x Fe x O 3-δ ( x = 0.2, 0.3, 0.4, 0.5, 0.67, LSCrFe), was synthesized and examined as both single phase and LSCrFe–Gd 0.1 Ce 0.9 O 2-β (GDC) composite solid oxide fuel cell anodes in full cells with La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-ε /La 0.4 Ce 0.6 O 2 bilayer electrolytes. Each anode demonstrated marked improvement in polarization resistance compared to prior studies on Fe-free La 1– x Sr x CrO 3-δ -based anodes and in stability compared to studies on more Fe-rich compositions. Higher Fe content anodes yielded lower polarization resistances, with the x = 0.67 anodes obtaining resistances of 0.275 Ω·cm 2 for LSCrFe and 0.333 Ω·cm 2 for LSCrFe-GDC in humidified H 2 at 800 °C. The lower polarization resistance with increasing Fe content can be attributed to oxygen loss, which introduces significant ionic conductivity into these perovskites. Substitution of an intermediate amount of Fe and Sr into the perovskites can thus optimize anode performance.