Performance ofmix-impregnated CeO₂- Ni/YSZ anodes for direct oxidation of methane in solid oxide fuel cells

CeO₂-Ni/YSZ anodes for methane direct oxidation were prepared by the vacuum mix-impregnation method. By this method, NiO and CeO₂ are obtained from nitrate decomposition and high temperature sintering is avoided, which is different from the preparation of conventional Ni-yttria-stabilised zirconia(YSZ) anodes. Impregnating CeO₂ into the anode can improve the cell performance, especially, when CH₄ is used as fuel. The investigation indicated that CeO₂- Ni/YSZ anodes calcined at higher temperature exhibited better stability than those calcined at lower temperature. Under the testing temperature of 1,073 K, the anode calcined at 1,073 K exhibited the best performance. The maximum power density of a cell with a 10 wt.-%CeO₂-25 wt.-%Ni anode calcined at 1,073 K reached 480 mW cm ^-2 after running on CH₄ for 5 h. At the same time, high discharge current favoured cell operation on CH₄ when using these anodes. No obvious carbon was found on the CeO₂-Ni anode after testing in CH₄ as revealed from SEM and corresponding linear EDS analysis. In addition, cell performance decreased at the beginning of discharge testing which was attributed to the anode microstructure change observed with SEM.