Low-cost micron-sized silicon/carbon anode prepared by a facile ball-milling method for Li-ion batteries

Commercially, Si nanoparticles (nano Si) are blended with graphite to construct high-capacity Si/C anodes. However, this strategy falls short because of the high cost of nano Si, serious pollution due to the use of organic solvent, and weak physical-electrical connection between graphite and Si. Herein, using low-cost micron-sized Si (μSi) and graphite as the raw materials, we proposed a facial ball-milling method to construct high-performance Si/C anode (μSi/C@CH) in which milled Si particles are protected both by graphite matrix and homogeneous chitosan-derived carbon layer. It is shown that the N and O atoms not only tend to coordinate with Li+, generating uniformly-distributed Li+ transport channels, but also improve the electrical conductivity of the anode materials. As a result, μSi/C@CH shows high cycling stability (376.7 mAh g-1 at 0.5 A g-1 after 500 cycles) and good rate capability of 120.2 mAh g-1 at 5 A g-1. This dual protection strategy facilitates the practical application of Si/C materials in high-energy density Li ion batteries (LIBs).