IMPRS - Guest Lecture : The Frequency Response Analysis of Electrochemical Systems by Prof. Fabio La Mantia.

Abstract: The frequency response of electrochemical systems is often investigated through electrochemical impedance spectroscopy (EIS). This technique, although capable of looking at phenomena occurring in the electrochemical system or at the interface on a broad range of time constants (frequencies), is limited to equilibrium or sufficiently stationary conditions. However, this limitation does not rise from an intrinsic property of impedance spectra, but rather from the measurement method and its operational definition. Electrochemical systems, which are intrinsically non-linear and often time variant, require however a more advanced method for an in operando frequency response analysis performed under non-stationary conditions. In order to reach this goal, dynamic multifrequency analysis (DMFA) can be used to acquire dynamic impedance spectra in a large range of frequencies and with high time-resolved precision [1,2]. Starting from the physical definition of impedance and admittance, and using the concept of Volterra series and the seminal work of Volterra on functionals [3], it is shown how the reconciliation the concept of dynamic impedance and the one of stationary impedance [4]. Here, the basics and some exemplary applications of DMFA will be shown.
1. A. Battistel, G. Du and F. La Mantia, Electroanal. 28 (2016) 2346
2. D. Koster, G. Du, A. Battistel, and F. La Mantia, Electrochim. Acta 246 (2017) 553
3. V. Volterra, “Theory of Functionals and of Integral and Integro-Differential Equations”, Dover, New York, 1959
4. A. Battistel, and F. La Mantia, Electrochim. Acta (2019) 513