Electrical conductivity and diffusion of oxygen ions in rare-earth-doped ceria

An oxalate coprecipitation method was applied to produce rare-earth-doped ceria powders (Ce0.8R0.2O1.9, R=Yb, Y, Gd, Sm, Nd and La). The powders calcined at 600 degreesC were isostatically compacted and sintered at 1600 degreesC in air to reach a relative density exceeding 98%. The electrical conductivity of rare-earth-doped ceria ceramics was dominated by the migration of oxygen ions in the bulk and was in the range of 6.7 to 13.6 S(.)m(-1) at 800 degreesC. The activation energies for diffusion of oxygen ions in the bulk ranged from 75.3 to 93.4 kJ/mol. The lattice energy theory for the fluorite structure was applied to estimate the activation energy. The calculated activation energy was close to the measured value.