Once upon a time there was EIS

During the second half of the 19th century, electrochemists began to measure the impedance of an electrode immersed in an electrolyte using alternating currents. At the turning of the 20th century some first models of the kinetics of the electrochemical reactions between an electrode and an electrolyte were published to explain the impedances achieved. They were particularly dealing with diffusion and adsorbed intermediates. However, in these times, experiments limited to the acoustical frequencies showed only a capacitance and a resistance. It is only at the end of the sixties in the 20th century that the possibility to perform impedance measurements down to very low frequencies allows these models to be tested. During the following years, thanks to the improvement of the measurement techniques towards low frequencies, with the help of new equipment, numerous electrochemical systems were investigated and various models were proposed. Therefore, at the end of the eighties it was decided to report on the advances of the electrochemical impedance spectroscopy (EIS) approach by organizing a meeting dedicated to this technique and its applications. So, the First International Symposium on the Electrochemical Impedance Spectroscopy was organized in June 1989 in Bombannes (France). During the next thirty years many developments of EIS arose concerning various applications and techniques. Hence, new transfer functions based on frequency analysis of different quantities which control the electrochemical kinetics, local impedance measurements for non-homogeneous electrodes were derived to obtain rate constants and diffusion coefficients of interfacial phenomena. (c) 2019 Elsevier Ltd. All rights reserved.