PDF(Pubmed)
Abstract：
Covalent organic frameworks (COFs) have emerged as promising renewable electrode materials for LIBs and gained significant attention, but their capacity has been limited by the densely packed 2D layer structures, low active site availability, and poor electronic conductivity. Combining COFs with high-conductivity MXenes is an effective strategy to enhance their electrochemical performance. Nevertheless, simply gluing them without conformal growth and covalent linkage restricts the number of redox-active sites and the structural stability of the composite. Therefore, in this study, a covalently assembled 3D COF on Ti3C2 MXenes (Ti3C2@COF) is synthesized and serves as an ultralong cycling electrode material for LIBs. Due to the covalent bonding between the COF and Ti3C2, the Ti3C2@COF composite exhibits excellent stability, good conductivity, and a unique 3D cavity structure that enables stable Li+ storage and rapid ion transport. As a result, the Ti3C2-supported 3D COF nanosheets deliver a high specific capacity of 490 mAh g-1 at 0.1 A g-1, along with an ultralong cyclability of 10,000 cycles at 1 A g-1. This work may inspire a wide range of 3D COF designs for high-performance electrode materials.
摘要：
共价有机骨架（COFs）已成为有前途的LIB可再生电极材料，并获得了广泛关注。但是它们的容量受到密集堆积的2D层结构的限制，活动站点可用性低，和差的电子导电性。将COF与高导电性MXene结合是增强其电化学性能的有效策略。然而，简单地粘合它们而没有共形生长和共价连接限制了氧化还原活性位点的数量和复合材料的结构稳定性。因此,在这项研究中，合成了在Ti3C2MXenes（Ti3C2@COF）上共价组装的3DCOF，并用作LIB的超长循环电极材料。由于COF和Ti3C2之间的共价键合，Ti3C2@COF复合材料表现出优异的稳定性，良好的导电性，以及独特的3D腔结构，可实现稳定的Li+存储和快速的离子传输。因此,Ti3C2支持的3DCOF纳米片在0.1Ag-1时可提供490mAhg-1的高比容量，以及在1Ag-1时10,000次循环的超长循环能力。这项工作可能会激发各种高性能电极材料的3DCOF设计。
