Stable, Low Polarization Resistance Solid Oxide Fuel Cell Anodes: La1-xSrxCr1-xFexO3-δ (x=0.2-0.67)

The perovskite series, La1-xSrxCr1-xFexO3-delta (x = 0.2, 0.3, 0.4, 0.5, 0.67, LSCrFe), was synthesized and examined as both single phase and LSCrFe-Gd0.1Ce0.9O2-beta (GDC) composite solid oxide fuel cell anodes in full cells with La0.9Sr0.1Ga0.8Mg0.2O3-epsilon/La0.4Ce0.6O2 bilayer electrolytes. Each anode demonstrated marked improvement in polarization resistance compared to prior studies on Fe-free La1-xSrxCrO3-delta-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 Omega.cm(2) for LSCrFe and 0.333 Omega. cm(2) for LSCrFe-GDC in humidified H-2 at 800 degrees 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.