TY  - JOUR
AU  - Schalenbach, Maximilian
AU  - Durmus, Yassin Emre
AU  - Tempel, Hermann
AU  - Kungl, Hans
AU  - Eichel, Rüdiger-A.
TI  - Double layer capacitances analysed with impedance spectroscopy and cyclic voltammetry: validity and limits of the constant phase element parameterization
JO  - Physical chemistry, chemical physics
VL  - 23
IS  - 37
SN  - 1463-9076
CY  - Cambridge
PB  - RSC Publ.
M1  - FZJ-2021-05749
SP  - 21097 - 21105
PY  - 2021
AB  - Routinely, cyclic voltammetry (CV) or electrochemical impedance spectroscopy (EIS) are used in electrochemistry to probe the current response of a specimen. For the interpretation of the response, constant phase elements (CPEs) are used in the frequency domain based impedance calculus to parameterize the double layer. In this study, the double layer responses to the two measurement techniques are compared by probing a model-type polished gold electrode under potential and amplitude variation. The equivalent circuit that describes the double layer includes a CPE and is parameterized by impedance data, while a computational impedance-based Fourier transform model (source code disclosed) is used to describe the CV response. With CV, the measured and modelled responses show good agreement at amplitudes below 0.2 V and within a certain scan rate window. At larger amplitudes, the ion arrangement in the double layer is actively changed by the measurement, leading to potential dependencies and deviations from the CPE behaviour. These varying contributions to the impedance measurements are not respected in the impedance calculus that relies on a sinusoidal response. The transition from perturbations of the double layer equilibrium to distortions of the ion arrangements is analysed with both measurement methods.
LB  - PUB:(DE-HGF)16
C6  - pmid:34523643
UR  - <Go to ISI:>//WOS:000695965100001
DO  - DOI:10.1039/D1CP03381F
UR  - https://juser.fz-juelich.de/record/904179
ER  -