A Self-Trapping, Bipolar Viologen Bromide Electrolyte for Redox Flow Batteries
A Self-Trapping, Bipolar Viologen Bromide Electrolyte for Redox Flow Batteries
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DOI：
10.1021/acsenergylett.1c01146
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发表时间：
2021-08
影响因子：
22
通讯作者：
Wenda Wu;Jian Luo;Fang Wang;Bing Yuan;T. L. Liu
中科院分区：
文献类型：
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作者：
Wenda Wu;Jian Luo;Fang Wang;Bing Yuan;T. L. Liu
水性有机氧化还原液流电池（AORFB）对于可扩展的能量存储变得越来越有吸引力。然而，由于缺乏高氧化还原电位的阴极电解液，开发高电压、强大的AORFB仍然具有挑战性。在此，我们报告甲基紫精二溴化物（[MV] Br 2）作为一种容易的自捕集，双极性氧化还原电解质材料的pH中性氧化还原液流电池的应用，代表甲基紫精作为一个高效的溴络合剂的第一份报告。[MV]（Br 3）2配合物的形成是计算预测和实验证实。在电池充电过程中，阴极电解液中的低溶解度[MV]（Br 3）2络合物不仅减轻了带电三溴物种（Br 3-）的交叉，而且同时解决了挥发性溴的毒性问题。1.53 V双极MV/Br AORFB（10.2 Wh/L）在pH中性条件下提供稳定的电池性能，具体而言，100%的总容量保持率，133 mW/cm 2功率密度和56%的能量效率（60 mA/cm 2）。
Aqueous organic redox flow batteries (AORFBs) have become increasingly attractive for scalable energy storage. However, it remains challenging to develop high-voltage, powerful AORFBs because of the lack of a high redox potential catholyte. Herein, we report methyl viologen dibromide ([MV]Br2) as a facile self-trapping, bipolar redox electrolyte material for pH-neutral redox flow battery applications, representing the first report of methyl viologen as a highly efficient bromine complexing reagent. The formation of the[MV](Br3)2complex was computationally predicted and experimentally confirmed. The low-solubility[MV](Br3)2complex in the catholyte during the battery charge process not only mitigates the crossover of charged tribromide species (Br3–) but also addresses the toxicity concern of volatile bromine simultaneously. A 1.53 V bipolar MV/Br AORFB (10.2 Wh/L) delivered stable battery performance at pH-neutral conditions, specifically, 100% total capacity retention, 133 mW/cm2power density, and 56% energy efficiency at 60 mA/cm2.