While the choices of active materials for redox flow batteries (RFBs) have grown substantially, very few can adequately serve in the positive side of a RFB. We attempt to address the challenge with an inexpensive, high-potential tris(bipyridyl)iron complex. Paired with methyl viologen, the complex enables a 1.4 V neutral RFB with 215 cycles at a current efficiency of 99.8% and capacity retention over 99.9% per cycle. The discharging process displays two peculiar plateaus due to the dimerization of ferric complexes, as confirmed by ex situ cyclic voltammetry and the UV–vis spectroscopy.

中文翻译：

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通信—用于高压水氧化还原液流电池的三（联吡啶）铁配合物

尽管用于氧化还原液流电池（RFB）的活性材料的选择已经大大增加，但很少能充分用作RFB的正极。我们试图通过一种廉价的，高潜力的三（联吡啶）铁络合物来应对这一挑战。与甲基紫精配合使用时，该复合物可实现215个循环的1.4 V中性RFB，电流效率为99.8％，每个循环的容量保持率超过99.9％。异位循环伏安法和紫外可见光谱法证实，由于三价铁配合物的二聚作用，放电过程显示出两个独特的平台。