A Density Functional Study of Oxygen Mobility in Ceria-Based Materials

In CeO2-based solid electrolytes, it has been shown that point defects are directly responsible for oxygen ionic conduction. The ionic conductivity is strongly affected by the anion vacancy concentration which is enhanced by doping with aliovalent cations. When rare earth sesquioxides such as La2O3, Gd2O3, Sm2O3, Y2O3 are added to CeO2, the dopant cation substitutes for the cerium ion, and oxygen vacancies are created for charge compensation. Incorporation of trivalent dopants into CeO2 at the Ce4+ sites can be depicted by the following defect reaction (expressed in Kroger-Vink notation):