Replacing inorganic anodes with organic electrode materials is an attractive direction for future green Li-ion batteries (LIBs). Carbonyl compounds are being explored as leading anode candidates for organic LIBs. In particular, cyclohexanehexanone (C₆O₆), as a perfect structure composed entirely of six CO groups, can theoretically contribute to the most reactive sites and the highest specific capacity, but has not been used as an anode material so far owing to its high solubility in carbonate-based electrolytes and extremely low electronic conductivity. Herein, C₆O₆ is first revealed as an ultra-high capacity and high-rate anode material through a total eight-electron redox electrochemical process by effectively constructing an insoluble and highly conductive C₆O₆-polymeric binder-carbon network architecture. Experimental characterizations combined with first-principles calculations elucidate that CO bonds in C₆O₆ can be lithiated to Li⁺ enolate (Li₆C₆O₆) through a reversible six-Li-ion electrochemical process and further converted to Li₈C₆O₆ dimers via a reversible two-electron pseudocapacitive Li⁺ intercalation reaction. As such, the C₆O₆ anode shows an ultrahigh capacity of up to 1404 mAh g⁻¹ at 200 mA g⁻¹ and an extraordinary high-rate durability (814 mAh g⁻¹ after 700 cycles at 5.0 A g−¹). A 4.3 V high energy/power density Li-ion hybrid electrochemical capacitor based on the C₆O₆ anode is thus derived.

中文翻译：

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用于高倍率大容量锂存储的八电子氧化还原环己酮阳极

用有机电极材料代替无机阳极是未来绿色锂离子电池（LIB）的一个有吸引力的方向。正在探索羰基化合物作为有机锂离子电池的主要阳极候选者。特别是环己烷己酮（C ₆ O ₆），作为完全由六个 CO基团组成的完美结构，理论上可以贡献最多的反应位点和最高的比容量，但迄今为止尚未用作负极材料由于其在碳酸盐基电解质中的高溶解度和极低的电子电导率。其中，C ₆ O _{6通过有效地构建不溶性和高导电性C 6} O ₆聚合物粘合剂-碳网络结构，通过总八电子氧化还原电化学过程首次揭示出作为超高容量和高倍率的负极材料。实验表征结合第一性原理计算表明，C ₆ O _6中的 CO键可以通过可逆的六锂离子电化学过程锂化为Li ⁺烯醇化物（Li ₆ C ₆ O _{6 ），并进一步转化为Li 8} C ₆ O ₆二聚体通过可逆的双电子赝电容 Li ⁺嵌入反应。因此，C ₆ O ₆负极在 200 mA g ^-1下显示出高达 1404 mAh g ^-1的超高容量和非凡的高倍率耐久性（在 5.0 A g-1 下 700 次循环后为^{814 mAh g -1}） . 由此得到基于C ₆ O _{6阳极的4.3 V高能量/功率密度锂离子混合电化学电容器。}