Electrical conductivity and defect equilibria of Pr0.1Ce0.9O(2-δ).

Praseodymium-cerium oxide (PCO) solid solutions exhibit mixed ionic electronic conductivity (MIEC) behavior in a relatively high and readily accessible oxygen partial pressure (P(O(2))) regime and as such serve as a model system for investigating the correlation between thermodynamic and kinetic properties and performance figures of merit in the areas of high temperature energy conversion, automotive control, and gas sensing applications. In this paper, we present measurements on the non-stoichiometry of Pr(0.1)Ce(0.9)O(2-δ) and develop a defect equilibria model to predict the dependence of the concentration of all the dominant charge carriers on temperature, P(O(2)), and Pr fraction. The predictive model is then employed to describe the measured electrical conductivity and oxygen nonstoichiometry whereby pre-exponentials and enthalpies of defect formation and migration are extracted.