Graphene-Encapsulated Si@C with Dual Carbon Layer Structure as High-Performance Anode Materials for Lithium-Ion Batteries

Silicon-based materials are among the highly promising anode candidates for Li-ion batteries owing to their excellent theoretical energy density. However, the huge volume variation makes the application of silicon anode in lithium-ion batteries be full of challenge. Herein, high-performance Si@C@rGO composites anode for lithium-ion batteries are successfully prepared by graphene oxide (GO) uniformly encapsulating resorcinol-formaldehyde resin (RF) coated silicon nanoparticles. The RF-derived carbon layer can prevent the silicon from direct contact with the electrolyte. Furthermore, the continuous conductive graphene network not only improves the overall electrical conductivity of the composite material, but also can be reversibly deformed with the volume change of silicon during the charging and discharging process, thus greatly improving the structural stability of the anode. The optimal Si@C@rGO-2 composite provides a high specific capacity of 743.9 mAh g--1 after 300 cycles at a current density of 1 A g-1. Meanwhile, the material also exhibits good rate performance, showing a good reversible capacity of 719.5 mAh g-1 even at a high current density of 2 A g-1. In addition, this simple and low-cost strategy of Si@C@rGO anode can provide a design reference for the further development of anode materials in lithium-ion batteries. Herein, dual carbon layer composites of graphene-encapsulated Si@C particles are prepared as silicon-based anode materials by anchoring Si@C particles in the rGO network through a simple electrostatic self-assembly method. The optimal Si@C@rGO-2 composite delivers 1038.5 mAh g-1 at 0.2 A g-1 after 200 cycles and 743.9 mAh g-1 at 1 A g-1 after 300 cycles, respectively. image