Volume 19, Issue 48 2305059
Research Article

Capacitive and Diffusive Contributions in Supercapacitors and Batteries: A Critique of b-Value and the ν–ν1/2 Model

Sheharyar Pervez

Sheharyar Pervez

ZENTECH Research Laboratory, Faculty of Engineering Sciences, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa, 23640 Pakistan

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Muhammad Zahir Iqbal

Corresponding Author

Muhammad Zahir Iqbal

ZENTECH Research Laboratory, Faculty of Engineering Sciences, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa, 23640 Pakistan

Nanotechnology Research Laboratory, Faculty of Engineering Sciences, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa, 23640 Pakistan

E-mail: [email protected]

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First published: 28 July 2023
Citations: 13

Abstract

Electrochemical energy storage devices run on two fundamentally different processes: charge storage across the double layer and redox reactions. A satisfactory understanding of the underlying mechanism is only possible once the two contributions are deconvoluted. The b-value and the ν −ν1/2 model are two familiar steps undertaken to separate these contributions but as it is shown here both metrics are flawed, prone to misinterpretation, frequently invoked without attention to their limitations, and in need of re-examination. After exploring these flaws through the lens of a diverse set of cyclic voltammetry data we opine that use of the b-value be discouraged on account of subjectivity inherent to the metric, and the ν −ν1/2 model be replaced by the one proposed here. This new model ultimately reduces the root mean square error significantly and provides a robust tool for the evaluation of energy storage devices.

Conflict of Interest

The authors declare no conflict of interest.

Data Availability Statement

The data associated with this article is available as part of a shiny app at https://walser52.shinyapps.io/mats.

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