Scalable synthesis of nano silicon-embedded graphite for high-energy and low-expansion lithium-ion batteries

Silicon is considered a highly promising anode material due to its environmental friendliness, natural abundance, and exceptionally high theoretical capacity for lithium-ion batteries. Nonetheless, substantial volume expansion impedes the economic viability of silicon anodes. This study involves the incorporation of silicon nanoparticles into a stable expanded graphite (EG)/pitch-derived carbon structure (EGC) following a reinforcing technique applied to EG using pitch. The EGC-Si composite, featuring silicon embedded within the EGC matrix, offers a durable architecture that effectively accommodates the significant volume changes of silicon particles during cycling. Furthermore, the engineered architecture of EGC-Si enhances ion diffusion while facilitating rapid electron transport through its varied porous architectures and carbon frameworks. The EGC-Si anode demonstrates a specific capacity of 699.9 mAh g⁻¹ at 0.1 A g⁻¹ and retains cycle stability over 400 cycles at 1.0 A g⁻¹. Furthermore, the EGC-Si electrode shows only a 6.6 % volume swelling ratio after full lithiation, which attribute to the well-designed ECG structure. This robust and well-integrated silicon/graphite structure offers a promising strategy to fully harness the potential of Si/Carbon composite anodes for high-performance lithium-ion storage.