A Study of SOFC Anodes Based on Cu-Ni and Cu-Co Bimetallics in CeO[sub 2]-YSZ

Abstract

A series of solid oxide fuel cells (SOFCs) with anodes containing mixtures of either Cu and Ni or Cu and Co, prepared by impregnation of the metal salts into porous yttria-stabilized zirconia (YSZ), were examined for operation with both H2 and n-butane fuels at 973 and 1073 K. The Cu-Ni mixtures formed single-phase alloys; however, anodes prepared with Cu 0.8Ni0.2 were found to be unstable in n-butane at 973 K if the alloy was reduced at 973 K, but stable if reduced at 1073 K, indicating a probable change in surface composition with reduction temperature. The addition of Ni to Cu significantly increased the performance of the cells for operation in H2, but caused no change in performance for n-butane. Unlike the Cu-Ni system, Cu-Co bimetallics formed two phases. It appears that Cu covers the surface of most of the Co, based on reduced CO adsorption and the fact that Cu0.5Co0.5 mixtures were stable for at least 3 h in n-butane at 973 K. Again, at 973 K, the addition of Co to Cu significantly increased the performance of the cells for operation in H2, but caused no change in performance for n-butane. At 1073 K, improved performance was observed for both H2 and n-butane with anodes based on Cu and Co. The results suggest that bimetallics are worth considering for fuel cells that operate on hydrocarbons. © 2004 The Electrochemical Society. All rights reserved.