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High‐Lithium‐Affinity Chemically Exfoliated 2D Covalent Organic Frameworks
Author(s) -
Chen Xiudong,
Li Yusen,
Wang Liang,
Xu Yi,
Nie Anmin,
Li Qianqian,
Wu Fan,
Sun Weiwei,
Zhang Xiang,
Vajtai Robert,
Ajayan Pulickel M.,
Chen Long,
Wang Yong
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201901640
Subject(s) - materials science , covalent organic framework , lithium (medication) , covalent bond , kinetics , electrode , chemical engineering , benzene , diffusion , ion , conjugated system , nanotechnology , composite material , organic chemistry , chemistry , polymer , medicine , physics , quantum mechanics , porosity , engineering , thermodynamics , endocrinology
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.