High Rate Performance Flake Si/C Composite Anode Materials of Lithium-Ion Batteries by Oxidization of an Industrial Si–Ca Alloy with CaCO3 in Molten Salt

High rate performance silicon/carbon composite anode materials are popular with lithium-ion batteries. Herein, a flaky silicon–carbon composite (FSCC) anode material with a high rate performance and its facile synthesis are investigated. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectra analyses show that the FSCC comprises flaky crystal Si embedded with or combined with amorphous carbon and a few and uniformly distributed crystal FeSi2. Benefiting from the special structure, the FSCC and especially the ball-milled FSCC exhibit a superior rate performance. Its rate capacity of ∼865 mA h g–1 at 2000 mA g–1 is 82.9% of that at 200 mA g–1. The synthesized method of oxidization of an industrial Si–Ca alloy with CaCO3 in molten CaCl2–NaCl at 600 °C for 1 h and the removal of salt with washing are simple, fast, and friendly to the environment, which shows great prospect for application in practice.