Journal Article

FZJ-2021-05748

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Physicochemical Mechanisms of the Double-Layer Capacitance Dispersion and Dynamics: An Impedance Analysis

Schalenbach, M. (Corresponding author)FZJ* ; Durmus, Y. E.FZJ* ; Robinson, S. A.FZJ* ; Tempel, H.FZJ* ; Kungl, H.FZJ* ; Eichel, R.-A.FZJ*RWTH*

2021
Soc. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/30162  doi:10.1021/acs.jpcc.0c11335

Abstract: Gold, as the noblest metal, is an appropriate model electrode to study electrochemical double layers. This study examines the frequency dispersion of the double layer of polished gold electrodes in perchloric acid with impedance spectroscopy under amplitude, electrolyte concentration, and potential variation. The dynamic perturbation of the double layer equilibrium by impedance measurements shows a constant phase (CP) response (phase angle of approximately −75°), which is responsible for a frequency dispersion of the capacitance. The response is almost independent of the excitation amplitude, for which the CP behavior is ascribed to resistive–capacitive (RC) contributions of the electric field-driven ion separation instead of the previously reported diffusion-limited adsorption processes. The RC character of the double layer in combination with the electrolyte resistance is accompanied by a relaxation that can damp the ion movement and the related ion separation. At the relaxation frequency, the capacitance is found to be independent of the electrolyte concentration, which is attributed to a constant ratio of the contributions of damped ion movement and dielectric polarization of water molecules.

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Contributing Institute(s):

1. Grundlagen der Elektrochemie (IEK-9)

Research Program(s):

1. 1232 - Power-based Fuels and Chemicals (POF4-123) (POF4-123)

Appears in the scientific report 2021

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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