Influence of dielectric layers on estimates of diffusion coefficients and concentrations of ions from impedance spectroscopy.

We present the analysis of the impedance spectra for a binary electrolyte confined between blocking electrodes with dielectric layers. An expression for the impedance is derived from Poisson-Nernst-Planck equations in the linear approximation taking into account the voltage drop on the dielectric layer. The analysis shows that characteristic features of the frequency dependence of the impedance are determined by the ratio of the Debye length and the effective thickness of the dielectric layer.