Silicon (Si) has been a focus material as lithium-ion battery (LIB) anode due to its ultrahigh theoretical specific capacity (4200 mA h/g). However, huge volume change (~400%) during cycling and low electrical conductivity have adversely affect its cycling life and rate performance, delaying its footstep as commercial anode of LIBs. Herein, vertical graphene sheets (VGSs) are grown on Si particles by thermal chemical vapor deposition, which forms a flexible and porous surface layer. The VGSs encapsulated Si particles (VGSs@Si) have a low volume deformation (12.9% in thickness after 100 cycles) and a high lithium ion diffusion coefficient (1.5 × 10⁻¹²–4.4 × 10⁻⁹ cm²/s), arising from good flexibility, high porosity, and excellent electrical conductivity of VGSs. As LIB anode, the VGSs@Si nanocomposite delivers a high reversible capacity of 2696.1 mAh/g, a long cycling life (500 cycles with capacity retention of 80.1% at 2 A/g), and an outstanding rate capability (457.9 mA h/g at 20 A/g). Remarkably, the full cell with prelithiated VGSs@Si as anode and commercial LiCoO₂ as cathode shows a high gravimetric energy density of 514.6 W h/kg and volumetric energy density of 1126.5 W h/L.

硅（Si）由于其超高的理论比容量（4200 mA h / g）而成为锂离子电池（LIB）阳极的焦点材料。但是，循环过程中体积的巨大变化（〜400％）和低电导率会对循环寿命和倍率性能产生不利影响，从而延迟了其作为LIB商用阳极的脚步。在此，通过热化学气相沉积在Si颗粒上生长垂直石墨烯片（VGS），这形成了柔性且多孔的表面层。VGSs封装的Si颗粒（VGSs @ Si）的体积变形小（100个循环后的厚度为12.9％）和高的锂离子扩散系数（1.5×10 ^-12 –4.4×10 ^-9 cm ^2）/ s），这归因于VGS的良好的柔韧性，高孔隙率和出色的导电性。作为LIB阳极，VGSs @ Si纳米复合材料可提供2696.1 mAh / g的高可逆容量，较长的循环寿命（500次循环，在2 A / g时的容量保持率为80.1％）和出色的倍率能力（457.9 mA h / g在20 A / g下）。值得注意的是，以预锂化的VGSs @ Si作为阳极，商用LiCoO ₂作为阴极的全电池显示出514.6 W h / kg的高重量能量密度和1126.5 W h / L的体积能量密度。