Investigation of the Ionic Conductivities of Yttria-Doped Ceria and Yttria-Stabilized Zirconia by Using the Statistical Moment Method

摘要

The ionic conductivities of yttria-doped ceria (YDC) and yttria-stabilized zirconia (YSZ), are investigatied using statistical moment method including the anharmonicity effects of thermal lattice vibrations. The expressions for the lattice constant and the vacancy activation energy are derived in closed analytic forms in terms of the power moments of the atomic displacements. The distribution of oxygen vacancies around dopants and the important role of cation barriers on vacancy diffusion are evaluated in detail. The lattice constants, activation energies, ionic conductivities of YDC and YSZ are calculated as functions of the dopant concentration. Notably, the ionic conductivities depend linearly on dopant concentration. Our results are in good agreement with those of both previous experiments and several theoretical calculations.