Excellent electrochemical performance with thin YSZ electrolyte for IT-SOFCs

摘要

Aiming to enhance the electrochemical performance of solid oxide fuel cells (SOFCs) and reduce the operation temperature down to 650 ?C, half cells (substrate, anode, electrolyte) with thin (~1 ?m thick) gas-tight yttria-stabilized zirconia (8 mol% YSZ) electrolyte layers were fabricated on tape-cast substrates by a combined sol-gel dip-/spin-coating method followed by heat-treatment at 1400 ?C for 5 h. A Ce0.8Gd0.2O2-δ protection layer and a La0.58Sr0.4Fe0.2Co0.8O3-δ cathode were further deposited on the sintered half cells via magnetron sputtering and screen printing, respectively. The microstructure and morphology of the samples were analysed by SEM. The performance of the cells was investigated by electrochemical single cell test and impedance spectroscopy (EIS). The as-prepared single cells showed excellent performance. At a cell voltage of 0.7 V, the extrapolated current density of the single cell is 1.57 A/cm2 at an operation temperature of 650 ?C. The area specific ohmic resistances of the single cells are 12 and 44 m?·cm2 at 800 and 650 ?C, respectively, which is >80% lower than the conventional SOFCs with 7~10 μm thick electrolyte manufactured by Forschungszentrum Jülich.