Performance improvement of inert-substrate-supported tubular single cells via microstructure modification

Inert-substrate-supported tubular single cells, with a configuration of porous yttria-stabilized zirconia (YSZ) supporter/Ni anode current collector/Ni-Ce0.8Sm0.2O1.9 anode/YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte/La0.6Sr0.4Co0.2Fe0.8O3−δ cathode, have been fabricated. The Ni anode current collector layer is prepared by a dip-coating process, while the cathode layer is produced by drop-coating and dip-coating processes, respectively. The electrochemical performances of the single cells are examined with respect to the microstructures of these two layers. The results indicate a significant effect of the Ni layer thickness on its sheet resistance and the ohmic resistance of the single cells. The preferred dip-coating time of the Ni layer is determined to be four. At 800 °C in hydrogen fuel, the single cell with a Ni layer dip-coated for four times and a drop-coated cathode layer exhibits a maximum power density of 500 mW cm−2. The electrochemical performance of the single cell is further enhanced by modifying its cathode microstructure. Preparing the cathode layer by dip-coating for four times allows a decrease of the overall electrode polarization by 25% and an increase of the maximum power density to 555 mW cm−2.