Thermal pyrolysis of Si@ZIF-67 into Si@N-doped CNTs towards highly stable lithium storage

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2020,（6）
• 页码范围: 452-459
• 页数: 8页
• 语种: 英文

摘要

Silicon is attracting considerable attention as an active anode material for advanced lithium-ion batteries due to its ultrahigh theoretical capacity.However,the reversible utilization of silicon-based anode materials is still hindered by the rapid capacity decay,as a consequence of the huge volume change of silicon during cycling.Herein,we use a Co-zeolitic imidazole framework (ZIF-67) to prepare silicon-wrapped nitrogen-doped carbon nanotubes (Si@N-doped CNTs) by controllable thermal pyrolysis.The asprepared nanocomposites can effectively prevent pulverization and accommodate volume fluctuations of silicon during cycling.It can deliver a highly reversible capacity of 1100 mAh g-1 even after 750 cycles at a current density of 1000 mA g-1.As confirmed by an in situ transmission electron microscopy experiment,the remarkable electrochemical performance of Si@N-doped CNTs is attributed to the high electronic conductivity and flexibility of cross-linked N-doped CNTs network as a cushion to mitigate the mechanical stress and volume expansion.Furthermore,a full cell consisting of Si@N-doped CNTs anode and LiFePO4 cathode delivers a high reversible capacity of 1264 mAh g-1 and exhibits good cycling stability (＞85％ capacity retention) over 140 cycles at 1/4 C (1 C =4000 mA g-1) rate.