Issue 10, 2024

Open circuit voltage of an all-vanadium redox flow battery as a function of the state of charge obtained from UV-Vis spectroscopy

Abstract

A unique feature of redox flow batteries (RFBs) is that their open circuit voltage (OCV) depends strongly on the state of charge (SOC). In the present work, this relation is investigated experimentally for the all-vanadium RFB (AVRFB), which uses vanadium ions of different oxidation states as redox pairs in both half-cells. In contrast to several literature studies, which use OCV measurements to deduce the SOC via the Nernst equation, we propose a method based on UV-Vis spectroscopy for SOC estimation, thereby enabling completely independent SOC and OCV measurements. Moreover, rather than relying on data at a single wavelength this UV-Vis method uses the entire absorption spectrum to obtain more robust values for the SOC. The obtained SOC-OCV data agree reasonably well with literature values and reveal a significant influence of the thermodynamic non-ideality of the solutions on the OCV as described by the Nernst equation.

Graphical abstract: Open circuit voltage of an all-vanadium redox flow battery as a function of the state of charge obtained from UV-Vis spectroscopy

Supplementary files

Article information

Article type
Paper
Submitted
06 Jun 2024
Accepted
05 Sep 2024
First published
13 Sep 2024
This article is Open Access
Creative Commons BY license

Energy Adv., 2024,3, 2597-2603

Open circuit voltage of an all-vanadium redox flow battery as a function of the state of charge obtained from UV-Vis spectroscopy

J. Heiß and M. Kohns, Energy Adv., 2024, 3, 2597 DOI: 10.1039/D4YA00360H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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