Chemical diffusion coefficients and ionic conductivities were measured, using both alternating-current and direct-current methods, in this mixed conductor at 160 and 200C, within the range of stoichiometric homogeneity. All of the measurements were carried out on the same symmetrical electrochemical cell. The stoichiometry of the α' phase was varied  in situ  by using coulometric titration, with AgI as a solid ionic conductor. The chemical diffusion coefficients and Ag ionic conductivities were deduced from the transient voltage response of ionic probes during polarization/depolarization experiments, as well as from an analysis of impedance data (using an equivalent circuit model). The alternating-current and direct-current results, regarding the compositional dependence of the chemical diffusion coefficient and the ionic conductivity of this material, were in complete agreement with each other; within the limits of experimental error.

R.Andreaus, W.Sitte: Journal of the Electrochemical Society, 1997, 144[3], 1040-4