Scalable synthesis of carbon-encapsulated nano-Si on graphite anode material with high cyclic stability for lithium-ion batteries

Alternative anode materials are required to meet the urgent demand for high-power density lithium-ion batteries (LIBs) since commercial graphite anode is approaching its limits. Silicon with ultrahigh specific capacity and large abundance is proposed to be an attractive substitute as high-performance anode material. However, the practical application of Si-based materials in LIBs is still impeded by unsatisfied cycling ability. Herein, carbon-encapsulated nano-Si on graphite hybrid composite (nano-Si/G/C) is elaborately designed and fabricated through a facile and scalable process. In this structure, Si nanoparticles are adhering on bulk graphite and further encapsulating by asphalt derived carbon. Graphite can guarantee the conductivity and asphalt derived carbon can buffer the volume changes of nano-Si with controlled amount (below 30 wt%) as well as limit the side reactions between nano-Si and electrolyte. The obtained nano-Si/G/C anodes with different areal mass loadings ranging from 0.968 mg cm−2 to 4.28 mg cm−2 exhibit high cyclic stability. Furthermore, nano-Si/G/C anodes with multifarious reversible specific capacities (400–820 mA h g−1) could be synthesized by adjusting the production process. The superior properties indicate that the proposed nano-Si/G/C composites are of great potential toward the practical application in LIBs.