Covalent organic frameworks (COFs) exhibiting both high ion redox capability and high electronic conductivity show potential as cathode materials for Li-ion batteries (LIBs). Specifically, expanding the conjugation planes of the COF materials as well as incorporating redox-active groups can enhance their performance. Here, we developed a class of COF synthesis methods based on aldol condensation and realized the construction of fully conjugated conducting COF materials. In contrast to the majority of COFs synthesized through Schiff base reactions, COFs formed via aldol condensation feature interconnecting units joined by carbon–carbon double bonds. This structural characteristic results in an expanded conjugation plane, facilitating the synthesis of fully sp²-conjugated COFs, denoted as TBI-COF-O and TBI-COF-N. Notably, TBI-COF-O exhibits an electrical conductivity of 7.5 × 10⁻⁴ (±5 × 10⁻⁵) S cm⁻¹ and a maximum capacity of 320 mA h g⁻¹ at a discharge rate of 0.1C, which are among the highest values reported for COF-based LIBs. Moreover, TBI-COF-O based LIBs maintained 99.8% specific capacity even after 500 cycles, with 245 mA h g⁻¹ at a discharge rate of 1C. This study further expands the variety of conjugated COFs and provides a new perspective on their use in energy storage.

中文翻译：

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具有高导电性的全共轭共价有机框架作为锂离子电池的优质正极材料


共价有机框架 （COF） 具有高离子氧化还原能力和高电子导电性，有望成为锂离子电池 （LIB） 的正极材料。具体来说，扩大 COF 材料的共轭面以及掺入氧化还原活性基团可以提高它们的性能。在这里，我们开发了一类基于羟醛缩合的 COF 合成方法，并实现了全共轭导电 COF 材料的构建。与通过席夫碱反应合成的大多数 COF 相比，通过羟醛缩合形成的 COF 具有由碳-碳双键连接的互连单元。这种结构特性导致扩大的偶联面，促进完全 sp² 偶联的 COF 的合成，表示为 TBI-COF-O 和 TBI-COF-N。值得注意的是，TBI-COF-O 的电导率为 7.5 × ^10-4 （±5 ^{× 10-5}） S ^cm-1，最大容量为 320 mA h ^g-1 在 0.1C 的放电速率下，这是基于 COF 的 LIB 报告的最高值之一。此外，基于 TBI-COF-O 的 LIBS 即使在 500 次循环后仍保持 99.8% 的比容量，在 1C 放电倍率下为 245 mA h ^g-1。这项研究进一步扩展了共轭 COF 的种类，并为它们在储能中的应用提供了新的视角。