Differential analysis of dynamic immittance spectra

• Published in: Electrochemistry communications Vol. 112; p. 106664
• Main Authors: Darowicki, K., Zieliński, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2020; Elsevier
• Subjects: Differential impedance analysis; Dynamic electrochemical impedance spectroscopy; Equivalent circuit modelling; Dynamic electrochemical impedance spectroscopy; Equivalent circuit modelling; Differential impedance analysis
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2020.106664

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•DEIS allows obtaining immitance derivative versus an independent variable.•System immittance is correlated with changes in the corresponding equivalent circuit.•Differentiation of the immittance allows separating contributions of circuit elements.•Differential analysis can facilitate selection of equivalent circuit topology.
This work presents a new approach to the analysis of immittance spectrograms of systems characterised by non-stationarity. The possibility of linking the evolution of the immittance response with changes in the parameters describing the system is achieved by introducing a spectrum in differential form. By using the above procedure, it becomes possible to separate elements with a dependence (or lack thereof) from an independent variable appearing in the dynamic electrochemical impedance method. The work illustrates the usefulness of this approach for the elementary components used to model the behaviour of electrochemical systems.