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The origin of the complex character of the ohmic impedance

Blanc, Christine and Orazem, Mark E. and Pébère, Nadine and Tribollet, Bernard and Vivier, Vincent and Wu, Shao-Ling The origin of the complex character of the ohmic impedance. (2010) Electrochimica Acta, vol. 55 (n° 21). pp. 6313-6321. ISSN 0013-4686

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Official URL: http://dx.doi.org/10.1016/j.electacta.2010.04.036

Abstract

The local and global Ohmic response for an electrode exhibiting geometry-induced potential and/or current distributions has recently been shown to be represented by a frequency-dependent complex impedance. A physical explanation for this result is provided in terms of the radial contribution to local current density and the decrease in current density along the current lines. Experiments performed with Cu/Al and Mg/Al galvanic couples show that, in regions where a radial current density does not exist, the local Ohmic impedance is independent of position; whereas, in regions where the radial current density cannot be neglected, the local Ohmic impedance is a function of position. Simulations performed on recessed electrodes show that, even in the absence of a radial current, an axial variation of current density gives rise to a complex Ohmic impedance. The complex character of the Ohmic impedance shows that an equivalent circuit, using the usual two-terminal resistor to represent the Ohmic contribution of the electrolyte, provides an inadequate representation of an electrode with geometry-induced current and potential distributions.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at Electrochimica Acta website : http://www.sciencedirect.com/science/journal/00134686
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Other partners > Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Other partners > University of Florida (USA)
Laboratory name:
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Deposited By: Leila Abdelouhab

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