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

Gd and Tb co-doped Ce0.8Gd0.2-xTbxO2-delta (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 Ce0.8Gd0.17Tb0.03O2-delta powders provided a high density, ultra-fine grain size, and high electrical conductivity even at the low sintering temperature of 1300 degrees C. The grain size and density of the Ce0.8Gd0.17Tb0.03O2-delta were similar to 146 nm and similar to 99% of the theoretical density, respectively, allowing enhanced electrical conductivity (0.106 Scm(-1) at 800 degrees C).