In situ electrochemical recomposition of decomposed redox-active species in aqueous organic flow batteries
In situ electrochemical recomposition of decomposed redox-active species in aqueous organic flow batteries
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DOI：
10.1038/s41557-022-00967-4
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发表时间：
2022-06-16
期刊：
影响因子：
21.8
通讯作者：
Aziz, Michael J.
中科院分区：
文献类型：
--
作者：
Jing, Yan;Zhao, Evan Wenbo;Aziz, Michael J.
水性有机氧化还原液流电池为存储间歇性可再生能源产生的大量电力的问题提供了一种安全且潜在廉价的解决方案。然而，分子分解是商业化的主要障碍，尽管结构修饰可以提高稳定性，但这是以牺牲合成成本和分子量为代价的。现在，利用2，6-二羟基蒽醌（DHAQ）而不进行进一步的结构修饰，我们证明了分解后原始分子的再生是实现低成本、长寿命的水性有机氧化还原液流电池的可行途径。我们使用原位（在线）NMR和电子顺磁共振以及互补电化学分析来表明分解化合物2，6-二羟基蒽酮（DHA）及其互变异构体2，6-二羟基蒽酚（DHAL）可以通过两个步骤电化学重组为DHAQ：通过单电子转移将DHA（L）（2-）氧化为二聚体（DHA）（2）（4-），然后通过每个DHAQ分子的三电子转移将（DHA）（2）（4-）氧化为DHAQ（2-）。这种电化学再生过程也使正电解质恢复活力-重新平衡两种电解质的电荷状态，而不引入额外的离子。
Aqueous organic redox flow batteries offer a safe and potentially inexpensive solution to the problem of storing massive amounts of electricity produced from intermittent renewables. However, molecular decomposition represents a major barrier to commercialization-and although structural modifications can improve stability, it comes at the expense of synthetic cost and molecular weight. Now, utilizing 2,6-dihydroxy-anthraquinone (DHAQ) without further structural modification, we demonstrate that the regeneration of the original molecule after decomposition represents a viable route to achieve low-cost, long-lifetime aqueous organic redox flow batteries. We used in situ (online) NMR and electron paramagnetic resonance, and complementary electrochemical analyses to show that the decomposition compound 2,6-dihydroxy-anthrone (DHA) and its tautomer, 2,6-dihydroxy-anthranol (DHAL) can be recomposed to DHAQ electrochemically through two steps: oxidation of DHA(L)(2-) to the dimer (DHA)(2)(4-) by one-electron transfer followed by oxidation of (DHA)(2)(4-) to DHAQ(2-) by three-electron transfer per DHAQ molecule. This electrochemical regeneration process also rejuvenates the positive electrolyte-rebalancing the states of charge of both electrolytes without introducing extra ions.