Stability and electrochemical performance of lanthanum ferrite-based composite SOFC anodes in hydrogen and carbon monoxide

Abstract

We here report a lanthanum ferrite-based perovskite anode La0.9Ca0.1Fe1-xNbxO3-δ (LCFNbx, x=0, 0.05, 0.1 and 0.2) for solid oxide fuel cells (SOFCs) with intriguing stability and electrochemical performance. The powders were prepared by citric acid-nitrate method. The LCFNbx/ScSZ ((Sc2O3)0.1(CeO2)0.01(ZrO2)0.89) composite anodes were constructed by infiltrating the corresponding metal nitrate solution into the ScSZ scaffold followed by heat treatment. X-ray diffractometer results indicated that Nb doping in B site can stabilize the material in the reducing atmospheres up to 800°C. The chemical stability of LCFNb0.1 is attributed to the constrained valence stability of Fe by the Nb introduction in highly charged state. The maximum power densities of the cell with LCFNb0.1/ScSZ composite anode were 467.1 and 375.8mW/cm2 in H2 and CO at 750°C, respectively. The area specific resistances of the cell at open circuit voltage were 0.75 and 2.30Ωcm2, respectively. Scanning electron microscopy results showed that the LCFNb0.1 layer was porous and well adhered to the ScSZ scaffold, which facilitated the electrochemical processes in H2 and CO. The obtained results in this paper indicate that the LCFNb0.1/ScSZ is a promising composite anode for the SOFCs with both high stability and high electrochemical performance in H2 and CO.