Preparation and Properties of Silicon Carbon Composites Using the Thermal Plasma Method

Silicon-carbon composites were prepared from industrial silicon powders and graphite powder using the thermal plasma method. The structure and properties of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Raman spectroscopy, and constant current charge-discharge tests. The results revealed that spherical nano-silicon/graphene can be prepared when the carbon content in raw materials is more than 30%. The size of the nano-sicilion/graphene prepared by the one-step method was about 6.6um×10.6um, and inserted nano-silicion were ∼30nm. The nano-silicon/graphene composites were used as negative active materials to make lithium-ion batteries. The first specific capacity was 339 mAh/g. The constant current charging and discharging tests were carried out at 1 C. The first discharge specific capacity was about 339 mAh/g and a reversible capacity of 150 mAh/g was retained after 50 cycles at a current density of 1000 mAh/g.