【摘要】 在锂离子电池负极材料中,硅具有超高的理论比容量,一直受到广泛的关注.然而,在充放电循环过程中,由于硅巨大的体积效应,导致电池容量快速的衰减,从而阻碍了硅基负极材料的可逆循环利用.本文使用共沸石咪唑骨架（ZIF-67）,通过热分解可控制备出氮掺杂碳纳米管包裹硅（Si@N-doped CNTs）纳米复合材料. Si@N-doped CNTs作为锂离子电池负极材料表现了出色的电化学性能,这是因为三维氮掺杂碳纳米管具有高电导率和柔韧性,从而可作为缓冲垫子,在充放电循环过程中,有效地阻止硅纳米颗粒的粉化和缓冲硅材料的体积膨胀,减小硅材料机械应力作用和体积膨胀效应.电化学测试结果表明,即使在1000 m A g^-1的电流密度下,经过750次循环后, Si@N-doped CNTs纳米复合材料仍表现出高度可逆循环容量,容量仍保持在1100 m Ah g^-1.此外,当Si@N-doped CNTs负极材料和Li Fe PO4正极材料组成全电池时,在1/4 C(1 C=4000 m A g^-1)倍率下,经过140个循环后仍可输出1264 m Ah g^-1的循环容量,并表现出良好的循环稳定性（容量保持率>85%）.更多还原

【Abstract】 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 m Ah g^-1 even after 750 cycles at a current density of 1000 m A 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 Li Fe PO4 cathode delivers a high reversible capacity of 1264 m Ah g^-1 and exhibits good cycling stability（>85% capacity retention） over 140 cycles at 1/4 C(1 C = 4000 m A g^-1) rate.更多还原