In the development of aqueous organic redox flow batteries (AORFBs), anthraquinone derivatives (AQs) attract a great deal of attention as the most promising negative electrolytes. The molecular structures of AQs have been engineered to maintain their long-term stability in aqueous media, which, however, requires tedious syntheses and multi-step purifications. Herein, we document the first case of a solvation regulation strategy to extend the lifetime of 2,6-dihydroxyanthraquinone (DHAQ) electrolytes, i.e., incorporating tetramethylammonium cations (TMA⁺) in the supporting electrolytes to interfere with the solvation structure of DHAQ²⁻/DHAHQ⁴⁻ anions, thereby deactivating the chemical or electrochemical reduction of DHAHQ⁴⁻ that initiates the subsequent side reactions. The ion pairing and hydration effect of TMA⁺ are elaborately demonstrated through experiments and simulations. The capacity fade rate of DHAQ/K₄Fe(CN)₆ cells caused by 0.1 M DHAQ electrolyte decomposition decreases by almost an order of magnitude, from 5.34% per day without TMA⁺ to 0.65% per day with 4.5 M TMA⁺. This strategy is effective when the DHAQ concentration is raised to 0.4 M. We anticipate that this mitigation strategy will readily extend to other organic redox-active molecules.

中文翻译：

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溶剂化调节减轻 2,6-二羟基蒽醌在水性有机氧化还原液流电池中的分解

在水系有机氧化还原液流电池（AORFBs）的开发中，蒽醌衍生物（AQs）作为最有前途的负极电解质而备受关注。AQ 的分子结构经过精心设计，可在水性介质中保持长期稳定性，然而，这需要繁琐的合成和多步纯化。在此，我们记录了第一个延长 2,6-二羟基蒽醌 (DHAQ) 电解质寿命的​​溶剂化调节策略案例，即在支持电解质中加入四甲基铵阳离子 (TMA ⁺ ) 以干扰 DHAQ ²⁻的溶剂化结构/DHAHQ ⁴⁻阴离子，从而使 DHAHQ 的化学或电化学还原失活⁴⁻启动后续的副反应。TMA ⁺的离子配对和水合作用通过实验和模拟得到了详尽的证明。由 0.1 M DHAQ 电解质分解引起_{的 DHAQ/K 4} Fe(CN) ₆电池的容量衰减率^{几乎降低了一个数量级，从没有 TMA +的每天 5.34% 到有 4.5 M TMA +}的每天 0.65%。当 DHAQ 浓度提高到 0.4 M 时，该策略是有效的。我们预计该缓解策略将很容易扩展到其他有机氧化还原活性分子。