Experimental study of current collection in single-chamber micro solid oxide fuel cells with comblike electrodes

The effect of current collection on the performance of single-chamber micro solid oxide fuel cells (SC-mu SOFCs) with coplanar interdigitated, comblike electrodes was studied. Conventionally employed current collection on the electrode segment linking together the single lines of the electrode comb was compared to applying gold mesh current collectors on the whole electrode surface. A simplified design was used with a comblike Ni-YSZ (yttria-stabilized zirconia) anode on one side of the YSZ electrolyte and a square, planar cathode made of (La(0.8)Sr(0.2))(0.98)MnO(3)-YSZ and (La(0.8)Sr(0.2))(0.98)MnO(3) on the opposite side. The cells were tested in methane-air mixtures at 700 degrees C. Current collection on the whole anode surface led to a reduction in the ohmic cell resistance for the conduction and collection of generated electrons, and 50% more power could be extracted from the cell. A nickel-rich anode with 80 wt % Ni content was investigated to enhance electron transport and conduction, but Ni instability in fuel-air mixtures prevented a performance increase. Additionally, the Ni-richer anode was more affected by aging. Collecting the current from the whole electrode surface area using suitable current collector designs will contribute to increasing the performance output of SC-mu SOFCs with comblike electrodes in the interdigitated configuration. (C) 2008 The Electrochemical Society.