Overdamped Oscillator Model with a Complex Viscosity To Interpret Impedance Spectroscopy Data

We propose a new framework to interpret impedance spectroscopy data by taking into account the ionic motion near to the electrodes limiting the electrolytic sample. This ionic motion is described by an overdamped harmonic oscillator model (ODO). We introduce a complex viscosity approach that has some equivalence with an anomalous diffusion model. The results show that this complex viscosity model predicts an impedance behavior that is very similar to the one predicted by an equivalent circuit having a constant phase element (CPE). We demonstrate that this mechanical model based on the overdamped oscillator has always an equivalent circuit, and both approaches may be applied to analyze impedance spectroscopy data, especially in the low-frequency region.