Nano-silicon composite lithium ion battery anode material coated with poly (3,4-ethylenedioxythiophene) as carbon source and preparation method thereof

A silicon/carbon composite material as a negative electrode for a lithium ion battery, having a nano-silicon powder as an active substance, and a carbon coating outside the nano-silicon powder being S-doped carbon, the S-doped carbon being obtained by carbonization of substances including a conductive polymer poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid as a dispersant of poly(3,4-ethylenedioxythiophene), said silicon/carbon composite material as the negative electrode for the lithium ion battery being prepared using a method comprising the steps of:

• (1) adding a precursor monomer 3,4-ethylenedioxythiophene into a water solution of the polystyrene sulfonic acid and performing homogeneous dispersion treatment;
• (2) adding the nano-silicon powder to a solution obtained in step (1), and then performing ultrasonic dispersion and uniformly stirring;
• (3) adjusting the pH value of the solution in step (2) by using 2M hydrochloric acid;
• (4) dropwise adding a water solution of (NH4)2S2O8/FeCl3 into the solution in the step (3) under an ice bath condition for being used as a catalyst;
• (5) firstly subjecting the mixed solution in the step (4) to an ice bath for 6 hours and then reacting at room temperature for 18 hours, and filtering to get a Si/PEDOT:
• PSS composite;
• and
• (6) heating the Si/PEDOT:
• PSS composite to 800-1000° C. under protective gas, performing heat preservation and carbonization, and cooling after an end of a reaction.