Vertical Graphene Nanosheets on Porous Microsilicon Particles for Anodes of Lithium-Ion Batteries

Silicon is receiving significant attention among different anode materials for Li-ion batteries due to its superhigh theoretical energy density. However, the commercial application of Si anode is facing huge obstacles because of the inferior electrical conductivity, the pulverization arising from the volume change, and the high cost of nanosilicon. Herein, we demonstrate a facile method to achieve excellent performance by in situ growing vertical graphene shell on microsilicon. The vertical graphene nanosheets can be conformally grown on porous microsilicon particles embedded with nanosilver particles to form the graphene-encapsulated porous Si@Ag particles (VG-PMSi@Ag). The unique structure integrates high conductivity and flexibility, which accelerate the charge transport and accommodate the volume change of silicon during the cycling process. As a result, the batteries exhibit a high initial discharge capacity of 3121.6 mAh·g–1 at 0.1 A·g–1 and a high rate capability of 943.8 mAh·g–1 at 6 A·g–1. A high reversible capacity of 1403.9 mAh·g–1 at 2.0 A·g–1 after 100 cycles is achieved. This approach offers insights into the fabrication of silicon anodes for high-performance lithium-ion batteries.