Conductive Rigid Skeleton Supported Silicon as High-Performance Li-Ion Battery Anodes

A cost-effective and scalable method is developed to prepare a core–shell structured Si/B4C composite with graphite coating with high efficiency, exceptional rate performance, and long-term stability. In this material, conductive B4C with a high Mohs hardness serves not only as micro/nano-millers in the ball-milling process to break down micron-sized Si but also as the conductive rigid skeleton to support the in situ formed sub-10 nm Si particles to alleviate the volume expansion during charge/discharge. The Si/B4C composite is coated with a few graphitic layers to further improve the conductivity and stability of the composite. The Si/B4C/graphite (SBG) composite anode shows excellent cyclability with a specific capacity of ∼822 mAh·g–1 (based on the weight of the entire electrode, including binder and conductive carbon) and ∼94% capacity retention over 100 cycles at 0.3 C rate. This new structure has the potential to provide adequate storage capacity and stability for practical applications and a good opportunity for large-scale manufacturing using commercially available materials and technologies.