Nanocomposite of Si/C Anode Material Prepared by Hybrid Process of High-Energy Mechanical Milling and Carbonization for Li-Ion Secondary Batteries

Abstract

Si/C nanocomposite was successfully prepared by a scalable approach through high-energy mechanical milling and carbonization process. The crystalline structure of the milled powders was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Morphology of the milled powders was investigated by Field-emission scanning electron microscopy (FE-SEM). The effects of milling time on crystalline size, crystal structure and microstructure, and the electrochemical properties of the nanocomposite powders were studied. The nanocomposite showed high reversible capacity of ~1658 mAh/g with an initial cycle coulombic efficiency of ~77.5%. The significant improvement in cyclability and the discharge capacity was mainly ascribed to the silicon particle size reduction and carbon layer formation over silicon for good electronic conductivity. As the prepared nanocomposite Si/C electrode exhibits remarkable electrochemical performance, it is potentially applied as a high capacity anode material in the lithium-ion secondary batteries.

Keywords

• silicon/carbon nanocomposite
• lithium-ion battery
• high-energy mechanical milling
• anode materials