Preparation and Electrochemical Performance of a Novel Perovskite Anode La0.9Ca0.1Fe0.9Nb0.1O3-δ for Solid Oxide Fuel Cells

The conventional Ni-YSZ anode as a cermet for solid oxide fuel cells (SOFCs) suffers from several shortcomings typically including low resistance to carbon coking, re-oxidation as well as sulfur poisoning. Perovskite anode as a potential substitute for Ni-YSZ anode has drawn much attention due to its impressive merits regarding carbon coking and re-oxidation resistance ability. In this study, a novel Nb-doped Fe-based perovskite anode candidate La0.9Ca0.1Fe0.9Nb0.1O3-delta was developed in which the addition of Nb greatly enhanced the structure stability in reducing atmosphere while the thermal expansion behavior was subtly influenced. The thermal expansion coefficient of the novel Nb-doped Fe-based perovskite anode changed from 11.67x10(-6)K(-1) to 11.57x10(-6)K(-1) after Nb doping while the electrical conductivity was greatly improved as well. At 800 degrees C the electrical conductivity of the novel Nb-doped Fe-based perovskite anode in H-2 reached up to 1.95 S/cm. The cell with La0.9Ca0.1Fe0.9Nb0.1O3-delta anode prepared by infiltration method presented high electrochemical performance. The maximal power densities in H-2 and CO at 800 degrees C were up to 539 and 491 mW/cm(2), respectively. It is remarkable that the cell has impressive long-term stability in pure CO at 800. for as long as 200 h. The results indicate that the perovskite La0.9Ca0.1Fe0.9Nb0.1O3-delta material is electrochemically active for both H-2 and CO oxidation which can be taken as a promising anode candidate for SOFCs practical applications.