FEM modelling of a coaxial three-electrode test cell for electrochemical impedance spectroscopy in lithium ion batteries

• Published in: Journal of power sources Vol. 240; pp. 273 - 280
• Main Authors: Klink, Stefan, Höche, Daniel, La Mantia, Fabio, Schuhmann, Wolfgang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-10-2013; Elsevier
• Subjects: Applied sciences; Computer simulation; Direct energy conversion and energy accumulation; Distortions; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Electrodes; Electrolytic cells; Exact sciences and technology; Finite element method; Geometry; Impedance; Lithium ion battery; Lithium-ion batteries; Mathematical models; Reference electrode; Finite element method; Geometry; Lithium ion battery; Distortions; Reference electrode; Electrochemical impedance spectroscopy; Lithium ion batteries; Secondary cell; Modeling
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.03.186

Electrochemical impedance spectroscopy for lithium ion batteries has recently gained increasing attention due to its ability of non-invasive evaluation of important electrochemical parameters. Commonly used three-electrode test cells, however, proved unreliable due to asymmetric current line distributions, causing severe distortions of impedance spectra. Finite element method (FEM) simulations can visualize these current lines at different frequencies and simulate impedance spectra at given geometries. By applying FEM simulations to a recently developed coaxial impedance test cell, limiting conditions for reliable impedance measurements could be identified. Using a reference electrode in coaxial position yields sufficiently reliable results as long as the electrode misalignment is small compared to the electrolyte thickness and edge effects are prevented.
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•Asymmetries in test cells lead to distortions of electrochemical impedance spectra.•FEM provides insight into the quality of impedance spectra for battery research.•Coaxial three-electrode test cells prove reliable with reasonable asymmetries.•Asymmetries, thin electrolytes and edge effects should be avoided.