A high-capacity negative electrode material for lithium ion battery and its preparation method of the silicon, a lithium ion battery

The present invention discloses a high-capacity negative electrode material for lithium ion battery and its preparation method of the silicon, a lithium ion battery, the material comprises nano-silicon, graphite, pyrolytic carbon and organic lithium fluoride, for the preparation of nano-silicon, graphite, and pyrolytic carbon organic precursor are mixed, dried and baked in vacuo, to give a composite material precursor, and then firing the composite material precursor to obtain a composite material coated with pyrolytic carbon, a lithium salt solution and reused in the composite fluoride solution situ on the surface of lithium fluoride reacted material cladding layer, i.e. to obtain high-capacity lithium ion battery anode material silicon. The present invention is by in situ generation of lithium fluoride on the silicon surface of the composite material, improve the interfacial properties of the material, to improve the compactness and stability of the solid electrolyte membrane material formed during the first lithium insertion, thereby improving the material the electrochemical performance of the battery in the initial charge-discharge efficiency of 80% or more, 50 times the capacity retention rate after charge and discharge cycles at 85% or more.