Carbon-silicon composite lithium ion battery cathode material and preparation method thereof

A carbon-silicon composite lithium ion battery cathode material and its preparation method are disclosed. Si which is used as an inner core is tightly coated with a SiO2 layer, and a hollow layer is arranged between the SiO2 layer and the outermost C coating layer. The inner core Si accounts for 30-70 wt% of mass of the composite material. The hollow layer is obtained by etching the SiO2 part of the middle layer on the synthesized Si/SiO2/C composite material. When used as a lithium ion battery cathode material in the field of electrochemical application, the material provided by the invention has advantages of high cyclic stability and high coulombic efficiency. There is less environmental pollution during the experimental process. The technology is easy to control and is suitable for large-scale industrial production.