Effects of a dc bias on electrical impedance spectroscopy in electrolytic cells

Characterization of electrolytic cells is often inferred from measurements of their electrical properties as afunction of frequency by applying a sinusoidal voltage. In some cases, a dc bias is intrinsically present inaddition to the ac stimulus and its effects are often neglected although they may become relevant in certainsituations. As a consequence, the interpretation of the observed results might be misleading. Our aim is toestimate the influence of the bias solving numerically the Poisson-Nernst-Planck model for an electrolyticcell submitted to an ac external voltage superimposed to a bias. According to our analysis, even in the caseof a small bias, the estimated Debye frequency and the low-frequency resistance of the cell are significantlyinfluenced by it.