Silicon is Embedded in Graphene Layers Through High-Energy Ball Milling as the Anode Material for Lithium-Ion Batteries

Abstract

Using micron silicon as raw material and multi-layer graphene as carbon source, a sandwich-type silicon-carbon composite material is prepared by high-energy ball milling, in which micro-silicon particles are uniformly embedded between the layers of multi-layer graphene. In the process of lithium deintercalation, the graphene sheet can effectively suppress the volume expansion of silicon, thereby improving the high cycle performance and electronic conductivity of the negative electrode of lithium ion batteries. The results show that the average discharge specific capacities are 3094.8, 2406.1, 1845.2, 1210.1, 657.3mAh/g at current densities of 200, 400, 800, 2000, and 4000mAh/g. Each current density is cycled for 5 cycles. When returning from high current to low current, the capacity can still remain at 1729.4 mAh/g, which is greatly improved compared to 671.4 mAh/g of pure silicon. important meaning. It is of great significance for the application of high-capacity silicon carbon anodes.