Molecular Mechanism and Electrostatic Effect Enabling Symmetric All-Quinone Aqueous Redox Flow Batteries

Symmetric all-quinone aqueous redox flow batteries (SQA-RFBs), in which the same quinone derivative is used as the electroactive compound in the negative and positive electrolytes, thereby obviating the need for a species-selective membrane, have been pursued as a potentially cost-effective and sust...

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Bibliographic Details
Published in:	ACS sustainable chemistry & engineering Vol. 12; no. 31; pp. 11488 - 11497
Main Authors:	Clarindo, José Eduardo dos Santos, Colombo, Rafael Neri Prystaj, Sedenho, Graziela Cristina, Faria, Luana Cristina Italiano, Bertaglia, Thiago, Lima, Filipe Camargo Dalmatti Alves, da Silva Gomes, Roberto, Aziz, Michael J., Crespilho, Frank Nelson
Format:	Journal Article
Language:	English
Published:	American Chemical Society 05-08-2024
Subjects:	redox flow battery carbon electrode symmetric battery alizarin red S quinone
Online Access:	Get full text
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Summary:	Symmetric all-quinone aqueous redox flow batteries (SQA-RFBs), in which the same quinone derivative is used as the electroactive compound in the negative and positive electrolytes, thereby obviating the need for a species-selective membrane, have been pursued as a potentially cost-effective and sustainable technology for stationary-electrical energy storage. Molecular decomposition during redox activity has frustrated all symmetric organic aqueous RFB development attempts. We used in situ/operando spectroelectrochemistry and density functional theory calculations to demonstrate that during the redox reaction of alizarin red S (ARS), a promising quinone for SQA-RFBs, intramolecular electronic oscillations form positively charged intermediates. Electrodes functionalized with net negative charge stabilize these intermediates via a hybrid adsorptive–diffusive electrochemical reaction mechanism, thereby enabling the cycling of the SQA-RFB. To understand the mechanism, spectroelectrochemical studies were performed on a series of electrodes with and without this functionalization. We report the performance of the first membraneless SQA-RFB prototype, containing ARS in the electrolyte storage reservoirs and instrumented with a reference electrode to evaluate the evolution of the half-cell potentials.
ISSN:	2168-0485 2168-0485
DOI:	10.1021/acssuschemeng.3c08218