Growth of Vertical Graphene Sheets on Silicon Nanoparticles Well‐Dispersed on Graphite Particles for High‐Performance Lithium‐Ion Battery Anode

With rapidly increasing demand for high energy density, silicon (Si) is greatly expected to play an important role as the anode material of lithium‐ion batteries (LIBs) due to its high specific capacity. However, large volume expansion for silicon during the charging process is still a serious problem influencing its cycling stability. Here, a Si/C composite of vertical graphene sheets/silicon/carbon/graphite (VGSs@Si/C/G) is reported to address the electrochemical stability issues of Si/graphite anodes, which is prepared by adhering Si nanoparticles on graphite particles with chitosan and then in situ growing VGSs by thermal chemical vapor deposition. As a promising anode material, due to the buffering effect of VGSs and tight bonding between Si and graphite particles, the composite delivers a high reversible capacity of 782.2 mAh g−1 after 1000 cycles with an initial coulombic efficiency of 87.2%. Furthermore, the VGSs@Si/C/G shows a diffusion coefficient of two orders higher than that without growing the VGSs. The full battery using VGSs@Si/C/G anode and LiNi0.8Co0.1Mn0.1O2 cathode achieves a high gravimetric energy density of 343.6 Wh kg−1, a high capacity retention of 91.5% after 500 cycles and an excellent average CE of 99.9%. Although silicon is a highly promising anode material for next‐generation lithium‐ion batteries, large‐scale synthesis of silicon anodes with good cyclability remains a major challenge. Therefore, the current commercialized mainstream anode products are silicon and graphite hybrid materials. In this article, a commercially viable method for preparing silicon/graphite anode materials is presented.