Structural studies of the new carbon-coated silicon anode materials using synchrotron-based in situ XRD

The structural changes of graphite-mixed and carbon-coated silicon, used as lithium intercalation materials, have been studied during discharge-charge using synchrotron-based in situ X-ray diffraction. The lithium intercalation (de-intercalation) takes place in the graphite first during discharge (charge), and then in the silicon. This graphite-lithium buffer combined with the uniformly distributed carbon coating greatly improve the quality and morphology of the Li-Si alloys formed at the surface of silicon powders. Therefore, the superior specific capacity and cycling performance are obtained for the graphite-mixed and carbon-coated silicon materials.