Fast time domain identification of electrochemical systems at low frequencies using fractional modeling

Abstract

Electrochemical Impedance Spectroscopy (EIS) is widely used in different types of applications to model accurately the internal battery behavior. EIS requires very long time to obtain experimental data, especially for diffusion phenomenon (low frequency). Therefore, fast chronopotentiometry experiment represents an interesting approach to solve this problem. This paper deals with the identification of diffusion electrochemical impedance parameters in time domain using fractional systems where EIS diffusion spectrum is obtained through the identified parameters from chronopotentiometry data. An Equivalent Electric Circuit (EEC) modeling using fractional systems is used to identify diffusion parameters. The method is validated using an experimental electrochemical cell and it shows accurate estimation for the diffusion parameters. Consequently, the fractional system is used as an identification tool to study the impact of external parameters on the diffusion aspects such as polarization point and working electrode rotation speed.