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 materia...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.展开更多
基金supported by the National Key Research and Development Program of China (2018YFA0209600)the National Natural Science Foundation of China (21872058)+1 种基金the Key Project of Science and Technology in Guangdong Province (2017A010106006)the Guangdong Special Support Program (2017TQ04N052)。
文摘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.
