Behaviour of 3, 4‐Dihydroxy‐9, 10‐Anthraquinone‐2‐Sulfonic Acid in Alkaline Medium: Towards a Long‐Cycling Aqueous Organic Redox Flow Battery. Issue 13 (5th July 2021)

• Record Type: Journal Article
• Authors: Guiheneuf, Solène; Lê, Aurore; Godet‐Bar, Thibault; Chancelier, Léa; Fontmorin, Jean‐Marie; Floner, Didier; Geneste, Florence
• Is Part Of: ChemElectroChem. Volume 8:Issue 13(2021)
• Page Start: 2526
• Page End: 2533
• Publication Date: 2021-07-05
• Subjects: quinones -- solubility -- energy density -- stability -- redox chemistry; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202100284
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The performance of a redox compound in redox flow batteries (RFB) highly depends on the electrolytic medium and operating conditions. It is exemplified in this work with the commercially available and relatively low‐cost dye 3, 4‐dihydroxy‐9, 10‐anthraquinone‐2‐sulfonic acid (ARS), which was used as negolyte in basic medium. At high pH, the ARS behavior revealed interesting features for RFB applications, such as a low half‐wave potential of −0.99 V ( vs Ag/AgCl), negatively shifted by phenolate groups, and an improved solubility compared with acidic medium depending on the nature of the cations. For the highly soluble ARS potassium salt (ARSK ), a maximum power density of 117 mW cm −2 and a demonstrated energy density of 20 Wh L −1 were obtained with K4 [Fe(CN)6 ] as posolyte. The capacity slightly decreased during cycling, reaching 90 % after 325 cycles. A long cycling of ARS sodium salt (ARSNa ) over 11 operating months was demonstrated in this work. A slow chemical degradation was highlighted giving rise to the formation of 3‐hydroxy‐9, 10‐anthraquinone‐2‐sulfonic acid (HAQS ) as the main degradation product due to hydrodeoxygenation reaction. Interestingly, this compound exhibited high performance in RFB and a good stability with a loss of capacity of 0.29 % per day. Abstract : A basic electrolyte led to an improved performance for 3, 4‐dihydroxy‐9, 10‐anthraquinone‐2‐sulfonic acid (ARS) in an aqueous organic redox flow battery, reaching a demonstrated energy density of 20 Wh L −1 for the highly soluble ARS potassium salt. A long cycling over 11 months was demonstrated, allowing the identification of a previously unknown degradation pathway of anthraquinone into new redox‐active species.