Crystallinity of silicon/carbon composite materials for rechargeable battery

The silicon battery's uncontrollable volume change during the lithiation process leads to a severely decreased battery life. Despite such a critical drawback of the material, the unparalleled capacity potential of silicon (Si) batteries is what makes it the next generation's most anticipated battery anode material. The first part of determining the capacity of a Si anode is the Si core itself. Our research indicated that the higher the purity of Si results in a naturally higher crystallinity status. When the purity of the sample was identical, monocrystalline Si proved to have higher crystallinity than polycrystalline and amorphous. The second part that determines the capacity is the graphite used in the composite. Natural Graphite (NG) have higher crystallinity values than Artificial Graphite (AG) and show more resistant properties to the crystallinity breaking down by milling time, which inspected by particle size analyzer, optical transmission and microscope. We reached a milling method of getting small particle sizes yet high crystallinity and graphene presence, which expect to improve the robustness of anode materials and electrochemical performances. The third part that determines coated carbon layers accommodate the volume change and prevents the quick loss of capacity, indicating higher crystallinity. Finally, the composites prepared with this method showed that higher X-ray Diffraction (XRD) and Raman Spectroscopy peaks than commercial references. We concluded how high crystallinity used in silicon carbon composite materials show high capacity potential with integrity in rechargeable battery.