DEFECT STRUCTURE AND OXYGEN DIFFUSIVITY OF NIOBIA DOPED CERIA

摘要

Donor doped ceria is one of the suitable candidates for Ni-free SOFC anode. Generally, the electrical conductivity is greatly related to anode performance. In order to elucidate the conduction mechanism, defect chemical analysis of Ce_(0.992)Nb_(0.008)O_(2-δ) was made by using data of electrical conductivity, oxygen nonstoichiometry and oxygen isotope diffusion. Our proposed defect model was essentially confirmed. The existence of oxygen interstitial was supported not only by oxygen hyper-nonstoichiometry in high oxygen partial pressure but by dependence of oxygen tracer diffusion coefficients on oxygen partial pressure.