Organic cathode materials are promising candidates for a new generation of “green batteries”, since they have low toxicity and can be produced from renewable resources or from oil. Especially suitable are organic redox polymers that can be reversibly oxidized and reduced. Because of their often-insulating nature, however, many redox polymers have limited rate capabilities. Their cycling stabilities, which are of high importance for the long cycle-life of a battery cell, rarely exceed 1000 cycles. Here, we present a new concept for redox polymers as cathode materials, in which the oxidized states are stabilized through π–π interactions between redox-active groups. We found that due to these interactions poly(3-vinyl-N-methylphenothiazine) showed excellent cycling stability (after 10 000 cycles at a 10C rate, 93% of the initial capacity was retained) in addition to a high rate capability because of supramolecular hole transport. We propose this concept to be used in the future design of redox polymers for batteries.

中文翻译：

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π-π相互作用导致的聚乙烯基吩噻嗪作为电池正极材料的超高循环稳定性

有机阴极材料毒性低，可以用可再生资源或石油生产，因此有望成为新一代“绿色电池”的候选材料。尤其合适的是可以可逆地氧化和还原的有机氧化还原聚合物。然而，由于它们通常是绝缘的性质，许多氧化还原聚合物具有有限的速率能力。它们的循环稳定性对于电池单元的长循环寿命至关重要，很少超过1000次循环。在这里，我们提出了一种将氧化还原聚合物用作阴极材料的新概念，其中氧化态通过氧化还原活性基团之间的π-π相互作用得以稳定。我们发现由于这些相互作用，聚（3-乙烯基-N-甲基吩噻嗪）由于具有超分子空穴传输能力，因此除了具有高倍率能力外，还显示出优异的循环稳定性（在10C速率下进行10 000次循环后，保留了93％的初始容量）。我们建议将此概念用于将来的电池氧化还原聚合物设计中。