APPLICATION OF CERIUM-BASED OXIDES WITH HIGH-SINTERING CHARACTERISTICS TO ELECTROLYTES IN INTERMEDIATE-TEMPERATURE SOLID OXIDE FUEL CELLS

摘要

The low-temperature sinterable rare earth-doped cerium oxide powders (Ce_(1-x)RE_xO_(2-δ), 0 ≤ x ≤ 0.2, RE = Y, La, Sm, Gd) have been synthesized through a pre-filtration heat-treatment process in a conventional coprecipitation method, and their sintering characteristics have been examined as electrolytes in intermediate-temperature solid oxide fuel cells. The precipitate obtained by the coprecipitation method was stirred at 80°Cfor 3 h. After filtrating this slurry, the precipitate was washed using pure water and was calcined at 700°C for 5 h in air. From the results of transmission electron microscopy and X-ray diffraction analysis, the powders showed uniform particle size of approximately 100 nm and its crystallite size was calculated to be approximately 20 nm. Sintering characteristics for all the doped cerium oxide powders were improved remarkably. Especially, the Ce_(0.9)Y_(0.1)O_(1.95) and Ce_(0.9)Gd_(0.1)O_(1.95) powders showed the highest sintering characteristics and their relative densities reached approximately 94% at 1050°C for 2 h.