Nano silicon composite negative electrode material for lithium ion battery, preparation method and lithium ion battery

The invention discloses a nano silicon composite negative electrode material, which comprises graphite matrix and a nano silicon material which is evenly deposited in the graphite matrix, wherein the nano silicon composite negative electrode material is prepared by chemical vapor deposition of nano silicon particles in hollow graphite with a silicon source. The nano silicon composite negative electrode material disclosed by the invention has the characteristics of high specific capacity (greater than 1,000mAh/g), high initial charge-discharge efficiency (greater than 93%) and high conductivity. The preparation method disclosed by the invention is simple to operate, easy to control, low in production cost and suitable for industrial production.