Silicon-carbon composite microsphere anode material and preparation method thereof

The invention discloses a silicon-carbon composite microsphere anode material and its preparation method. the preparation method comprises the following steps: firstly, nano-silicon particles and a first macromolecular solution are mixed, and first composite microspheres are formed after spray drying; then, the first composite microspheres and a second macromolecular solution are mixed to carry out surface coating on the first composite microspheres, and second composite microspheres with a core-shell structure are formed after solvent evaporation; and finally, the second composite microspheres undergo oxidation and carbonization treatments to form the silicon-carbon composite microsphere anode material. By the preparation method which has a simple technology, is low-cost and is easy to operate, the silicon-carbon composite microsphere anode material is prepared. In addition, no etching operation for pore-forming is required by the preparation method. Raw materials used in the preparation method can be selected from a number of sources. According to the silicon-carbon composite microsphere anode material obtained, advantages of nano-silicon and a carbon substrate are combined effectively. Thus, electrochemical performance of the silicon-carbon composite microsphere anode material used as a negative electrode of a lithium ion battery is enhanced.