Modeling Oxygen Ion Migration in the CeO2–ZrO2–Y2O3 Solid Solution

Abstract

Zirconium doping in cerium oxide, as a result of intentional material engineering or unintentional impurities, impacts material properties like reduction behavior and defect migration. In this study, we investigate the influence of zirconium doping on the conductivity of yttrium doped ceria using DFT+U calculations. We calculate the migration energies of oxygen ions for different jump environments containing yttrium and zirconium ions and compare the results to a simplified migration energy model. The small zirconium ions lead to strong distortions of the lattice, which results in deviation between calculated and modeled energies. Both the calculated and the modeled migration energies are used in kinetic Monte Carlo simulations to obtain the ionic conductivity for various dopant fractions. We identify three major influences on the ionic conductivity: the trapping of oxygen vacancies by dopant ions, the blocking effect, which alters the migration barriers around defects, and the lattice contraction due to ...