%0 Journal Article
%T The effects of time-variance on impedance measurements:
examples of a corroding electrode and a battery cell
%A Diard
%A Jean-Paul
%A Murer
%A Nicolas
%A Petrescu
%A Bogdan
%J -
%D 2020
%R 10.5599/jese.725
%X Sa£¿etak When performing electrochemical impedance spectroscopy (EIS) measurements on a system, we must make sure it fulfills certain conditions. One of them is that it should be stationary that is to say, steady-state and time-invariant. Commonly studied systems are time-variant, for example a corroding electrode or a battery under operation. A corroding electrode sees its polarization resistance decrease with time. A passivating electrode sees its polarization resistance increase with time. These phenomena cause a deformation of the Nyquist impedance at low frequencies. This result was first simulated and validated by experimental measurements on a corroding steel sample undergoing uniform corrosion. The effect of performing impedance measurements on a discharging battery was also shown. Several methods are available to check and correct time-variance. The nonstationary distortion (NSD) indicator is used to separate valid and invalid data samples and the so called ¡°4D impedance¡± method can easily produce instantaneous impedance data
%K EIS
%K non-stationarity
%K corrosion
%K in operando
%K battery cells
%K 4D impedance
%K NSD
%U https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=342174