关键词: 电化学阻抗谱, 物理模型, 数值方法

Abstract:

Electrochemical impedance spectroscopy (EIS) is a powerful electrochemical method from which many fundamental processes in the research system can be characterized, such as charge transfer, double-layer charging, and mass transport. Effective EIS analysis requires reasonable models. Typical models include equivalent circuit and physical models. This paper introduces three methods for solving physical EIS models, including analytical solutions, the time-space method, and the frequency-space method. We take a Faradaic electrochemical interface with diffusion-controlled mass transport as an example, deduce the analytical solution, introduce the time- and frequency-space methods to solve EIS numerically, and compare the results of different methods. Then, taking the typical metal-ion deposition reaction in rechargeable batteries as an example, we provide the analytical EIS solution at the potential of zero charges and compare the two numerical methods' accuracy. We compare the EIS results of metal ions with different valences. Our results show the frequency-space method's accuracy is higher than the time-space method and can be used as a first choice for the numerical EIS solution. When maintaining other parameters, the EIS of ions with high valence is smaller than ions with low valence. Finally, we summarize and compare the advantages and disadvantages of the above three methods. This study's results can be a guide to the physical EIS model and can be used to analyze the EIS results of the metal-ion deposition reaction.

Key words: electrochemical impedance spectroscopy, physical model, numerical methods