Preparation and electrochemical properties of core-shelled silicon–carbon composites as anode materials for lithium-ion batteries

Abstract

In this paper, core-shelled silicon–carbon composites as anode materials for lithium-ion batteries (LIBs) are prepared by a cost-effective method of the combined mechanical ball milling and high-temperature heat treatment. The microstructures and morphologies of such anode materials with different silicon contents are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis. Both coin and soft-packed LIBs are fabricated using these silicon–carbon composites as anode materials. The batteries can give high capacities of 377.7 mA h g−1, 418.5 mA h g−1, 450.9 mA h g−1, and 500.1 mA h g−1 at the silicon contents of 2.0%, 6.5%, 9.5%, and 14.5%, respectively. The effects of silicon content on the coulomb efficiency, low-temperature capacity, resistance, and cycle life are also studied, and the results show that a silicon content of 9.5% can give the best battery performance. Considering that the process has no surfactant, corrosive acidic or alkaline reagent added, and that the ball milling and heat treatment are efficient, cost-effective, and environmentally friendly, it can be expected that the fabrication process described in this paper should be usable for large-scale production of silicon–carbon composite materials for anodes of LIBs.