Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries

Abstract 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivatives are typical catholytes in aqueous organic redox flow batteries (AORFBs), but reported lifetime of them is limited. We find that the increase of Hirshfeld charge decreases the Gibbs free energy change (ΔG) values of side reactions of T...

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Main Authors: Gonggen Tang, Wenyi Wu, Yahua Liu, Kang Peng, Peipei Zuo, Zhengjin Yang, Tongwen Xu
Format: Article
Language:English
Published: Nature Portfolio 2025-01-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-024-55244-4
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author Gonggen Tang
Wenyi Wu
Yahua Liu
Kang Peng
Peipei Zuo
Zhengjin Yang
Tongwen Xu
author_facet Gonggen Tang
Wenyi Wu
Yahua Liu
Kang Peng
Peipei Zuo
Zhengjin Yang
Tongwen Xu
author_sort Gonggen Tang
collection DOAJ
description Abstract 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivatives are typical catholytes in aqueous organic redox flow batteries (AORFBs), but reported lifetime of them is limited. We find that the increase of Hirshfeld charge decreases the Gibbs free energy change (ΔG) values of side reactions of TEMPO, a near-linear relationship, and then exacerbates their degradation. Here we predict and synthesize a TEMPO derivative, namely TPP-TEMPO, by analyzing the Hirshfeld charge. TPP-TEMPO, with the smallest Hirshfeld charge and highest ΔG, is an order of magnitude more stable than TMA-TEMPO (N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride, a control with the largest Hirshfeld charge and lowest ΔG). We further elaborate on their decomposition pathways, identify byproducts, and mitigate degradation by supporting electrolyte engineering. Finally, a TPP-TEMPO/BTMAP-Vi (1,1′-bis[3-(trimethylammonio)propyl]-4,4′-bipyridinium tetrachloride) cell achieves a capacity density of ~12 Ah L− 1 and a low capacity fade rate of 0.0018% per cycle (or 0.0067% per hour).
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issn 2041-1723
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spelling doaj-art-b03aafbfa7ec4b11adeea6e21eedbb5a2025-01-05T12:39:18ZengNature PortfolioNature Communications2041-17232025-01-0116111010.1038/s41467-024-55244-4Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteriesGonggen Tang0Wenyi Wu1Yahua Liu2Kang Peng3Peipei Zuo4Zhengjin Yang5Tongwen Xu6Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of ChinaKey Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of ChinaSchool of Chemistry and Chemical Engineering, Hefei University of TechnologyKey Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of ChinaKey Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of ChinaKey Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of ChinaKey Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of ChinaAbstract 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivatives are typical catholytes in aqueous organic redox flow batteries (AORFBs), but reported lifetime of them is limited. We find that the increase of Hirshfeld charge decreases the Gibbs free energy change (ΔG) values of side reactions of TEMPO, a near-linear relationship, and then exacerbates their degradation. Here we predict and synthesize a TEMPO derivative, namely TPP-TEMPO, by analyzing the Hirshfeld charge. TPP-TEMPO, with the smallest Hirshfeld charge and highest ΔG, is an order of magnitude more stable than TMA-TEMPO (N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride, a control with the largest Hirshfeld charge and lowest ΔG). We further elaborate on their decomposition pathways, identify byproducts, and mitigate degradation by supporting electrolyte engineering. Finally, a TPP-TEMPO/BTMAP-Vi (1,1′-bis[3-(trimethylammonio)propyl]-4,4′-bipyridinium tetrachloride) cell achieves a capacity density of ~12 Ah L− 1 and a low capacity fade rate of 0.0018% per cycle (or 0.0067% per hour).https://doi.org/10.1038/s41467-024-55244-4
spellingShingle Gonggen Tang
Wenyi Wu
Yahua Liu
Kang Peng
Peipei Zuo
Zhengjin Yang
Tongwen Xu
Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries
Nature Communications
title Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries
title_full Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries
title_fullStr Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries
title_full_unstemmed Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries
title_short Adjusting Hirshfeld charge of TEMPO catholytes for stable all-organic aqueous redox flow batteries
title_sort adjusting hirshfeld charge of tempo catholytes for stable all organic aqueous redox flow batteries
url https://doi.org/10.1038/s41467-024-55244-4
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