Synthesis and Characterization of Nanocrystalline Gd and Tb Co-Doped Ceria-Based Electrolyte Materials for IT-SOFC

摘要

Gd and Tb co-doped Ce_(0.8)Gd_(0.2-x)Tb_xO_(2-δ) (0 ≤ x ≤ 0.09) nanopowders were synthesized by the combustion method using aspartic acid as fuel. The calcined powders formed a ceria-based single phase with a cubic fluorite structure. In addition, the powders were pure, homogeneous, and nanocrystalline nature, i.e., 20.1-23.4 nm in the calculated crystallite size. The partial incorporation of Tb for Gd caused a decrease in the average grain size of the sintered bodies. The high-quality nanosized Ce_(0.8)Gd_(0.17)Tb_(0.03)O_(2-δ) powders provided a high density, ultra-fine grain size, and high electrical conductivity even at the low sintering temperature of 1300℃. The grain size and density of the Ce_(0.8)Gd_(0.17)Tb_(0.03)O_(2-δ) were ～146 nm and ～99% of the theoretical density, respectively, allowing enhanced electrical conductivity (0.106 Scm~(-1) at 800℃).