Covalent organic frameworks (COFs) have attracted growing interest by virtue of their structural diversity and tunability. Herein, we present a novel approach for the development of organic rechargeable battery cathodes in which three distinct redox-active COFs were successfully prepared and delaminated into 2D few-layer nanosheets. Compared with the pristine COFs, the exfoliated COFs with shorter Li+ diffusion pathways allow a significant higher utilization efficiency of redox sites and faster kinetics for lithium storage. Unlike diffusion-controlled manners in the bulk COFs, the redox reactions in ECOFs are mainly dominated by charge transfer process. The capacity and potential are further engineered by reticular design of COFs without altering the underlying topology. Specifically, DAAQ-ECOF exhibits excellent rechargeability (98% capacity retention after 1800 cycles) and fast charge-discharge ability (74% retention at 500 mA g-1 as compared to at 20 mA g-1). DABQ-ECOF shows a specific capacity of 210 mA h g-1 and a voltage plateau of 2.8 V.

中文翻译：

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共价有机框架剥离成少层氧化还原活性纳米片作为锂离子电池的阴极材料

共价有机框架（COF）由于其结构多样性和可调性而引起了越来越多的兴趣。在此，我们提出了一种开发有机可充电电池正极的新方法，其中成功制备了三种不同的氧化还原活性 COF，并将其分层为二维少层纳米片。与原始 COF 相比，具有更短 Li+ 扩散路径的剥离 COF 允许显着更高的氧化还原位点利用效率和更快的锂存储动力学。与本体 COF 中的扩散控制方式不同，ECOF 中的氧化还原反应主要受电荷转移过程支配。在不改变底层拓扑结构的情况下，通过 COF 的网状设计进一步设计了容量和潜力。具体来说，DAAQ-ECOF 表现出优异的可充电性（1800 次循环后容量保持率为 98%）和快速充放电能力（500 mA g-1 时保持率为 74%，与 20 mA g-1 相比）。DABQ-ECOF 显示出 210 mAh g-1 的比容量和 2.8 V 的电压平台。