The invention discloses a nanometer
silicon and carbon composite negative
electrode material, a preparation method thereof and a
lithium ion battery. The nanometer
silicon and carbon composite negative
electrode material is of a core-shell structure. A gap is formed between the outer wall of a core body and the inner wall of a shell layer, wherein the core body is made of nanometer
silicon, and the shell layer is a nanometer
porous carbon layer. The preparation method of the nanometer silicon and carbon composite negative
electrode material comprises the steps of preparing nanometer silicon particles wrapped by SiO2; preparing nanometer silicon particles, wherein nanometer SiO2 is embedded into the nanometer silicon particles which are wrapped by organic carbon sources, and the surfaces of the nanometer silicon particles are oxidized; performing organic
carbon source splitting
decomposition on the nanometer silicon particles provided with the embedded nanometer SiO2 and oxidized surfaces and wrapped by the organic carbon sources, performing
etching processing on the SiO2 on the nanometer silicon particles provided with the embedded nanometer SiO2 and oxidized surfaces and wrapped by
amorphous carbon by adopting HF, and the like. The negative
electrode material of the
lithium ion battery is the nanometer silicon and carbon composite negative
electrode material. The nanometer silicon and carbon composite negative
electrode material and the
lithium ion battery are excellent in
cycling stability, specific capacity, rate capability and safety performance.