Colloidal Synthesis of Silicon-Carbon Composite Material for Lithium-Ion Batteries

We report colloidal routes to synthesize silicon@-carbon composites for the first time. Surface-functionalized Si nanoparticles (SiNPs) dissolved in styrene and hexadecane are used as the dispersed phase in oil-in-water emulsions, from which yolk-shell and dual-shell hollow SiNPs@C composites are produced via polymerization and subsequent carbonization. As anode materials for Li-ion batteries, the SiNPs@C composites demonstrate excellent cycling stability and rate performance, which is ascribed to the uniform distribution of SiNPs within the carbon hosts. The Li-ion anodes composed of 46 wt% of dual-shell SiNPs@C, 46 wt% of graphite, 5 wt% of acetylene black, and 3 wt% of carboxymethyl cellulose with an areal loading higher than 3 mg cm(-2) achieve an overall specific capacity higher than 600 mAh g(-1), which is an improvement of more than 100% compared to the pure graphite anode. These new colloidal routes present a promising general method to produce viable Si-C composites for Li-ion batteries.