Determination of Oxygen Diffusion and Surface Exchange Coefficients of Mixed Ionic-Electronic Conductors by Oxygen Semi-Permeation Methods

The understanding of oxygen transport mechanisms through mixed ionic-electronic conductors is of great interest for the development of electrochemical devices at high temperature for energy conversion applications. This study is focused on the determination of two coefficients-the oxygen diffusion coefficient and the surface exchange coefficient which are key parameters for the electrochemical performance of a material. These coefficients can be largely impacted by the measurement conditions. The oxygen semi-permeation method is an adequate method to determine these two fundamental coefficients close to the working conditions of the material, i.e., under small or large oxygen partial pressure gradients.