DEVELOPMENT OF NANO-STRUCTURED YSZ ELECTROLYTE LAYERS FOR SOFC APPLICATIONS VIA SOL-GEL ROUTE

Nano-structured YSZ thin films are promising candidates to enhance the electrolyte performance of solid oxide fuel cells operating at the intermediate temperature. In this work, the sot-gel synthesis was utilized for fabrication of very fine YSZ nanomaterials with a narrow particle size distribution and an average particle size of 7 nm. On top of the macroporous anode substrates, colloidal sols with graded particle size distribution were coated separately to form mesoporous intermediate layers, which served as the support for fine nano-sol coatings(1). Through controlling the experimental parameters, the graded colloidal sols were prepared with an average particle size in the range of 40-120 nm. The microporous YSZ layer prepared from a fine nano-sol showed a thickness of 50-200 nm and improved the gas-tightness of the electrolyte. The overall thickness of the multi-layered YSZ electrolyte was less than 3 pm after the thermal treatment. Electrical performance was measured after applying a LSCF cathode. The measured open circuit voltage (OCV) was comparable to that of sintered cells, indicating that a gas-tight electrolyte was fabricated. At 700 m V cell voltage, the cells showed a power density of 588 mW/cm(2) at 1073 K.