High‐Lithium‐Affinity Chemically Exfoliated 2D Covalent Organic Frameworks

作者：Xiudong Chen, Yusen Li, Liang Wang, Yi Xu, Anmin Nie, Qianqian Li, Fan Wu, Weiwei Sun, Xiang Zhang, Róbert Vajtai, Pulickel M. Ajayan, Long Chen, Yong Wang · 发表于：Advanced Materials · 年份：2019 · DOI：10.1002/adma.201901640 · 被引用次数：334 · 研究领域：Covalent Organic Framework Applications、Advancements in Battery Materials、Advanced Battery Materials and Technologies

Abstract Covalent organic frameworks (COFs) with reversible redox behaviors are potential electrode materials for lithium‐ion batteries (LIBs). However, the sluggish lithium diffusion kinetics, poor electronic conductivity, low reversible capacities, and poor rate performance for most reported COF materials limit their further application. Herein, a new 2D COF (TFPB‐COF) with six unsaturated benzene rings per repeating unit and ordered mesoporous pores (≈2.1 nm) is designed. A chemical stripping strategy is developed to obtain exfoliated few‐layered COF nanosheets (E‐TFPB‐COF), whose restacking is prevented by the in situ formed MnO 2 nanoparticles. Compared with the bulk TFPB‐COF, the exfoliated TFPB‐COF exhibits new active Li‐storage sites associated with conjugated aromatic π electrons by facilitating faster ion/electron kinetics. The E‐TFPB‐COF/MnO 2 and E‐TFPB‐COF electrodes exhibit large reversible capacities of 1359 and 968 mAh g −1 after 300 cycles with good high‐rate capability.