Scalable synthesis and performance optimization of silicon/ flake Graphite@Hard carbon composite anodes for lithium-ion batteries by wet ball milling

With the saturation of lithium-ion battery cathode materials research, anode materials have gained increasing attention for their potential advancements. Among them, silicon electrodes, with a theoretical capacity nearly ten times that of graphite, face challenges from significant volume expansion during the charge–discharge cycle, leading to capacity fading and reduced cycle life. Therefore, this study shows a scalable and economical approach. Firstly, silicon anodes were improved through the preparation of silicon/graphite composites via wet ball milling. Subsequently, the phenolic resin was used as a coating and sintered to create a robust carbon layer, which serves to strengthen the composite structure and reduce the volume expansion of silicon. The composite was prepared with 800 mesh flake graphite, silicon-carbon ratio 1:2, ball milling for 5 h and coated with hard carbon (Si/FG@HC-800-125) shows remarkable electrochemical performance, reaching an initial discharge specific capacity of 1024.5 mAh/g and an initial Coulombic efficiency of 86.9%, with a capacity retention rate of 62.92% after 200 cycles. The findings show that the combination of wet ball milling and hard carbon coating effectively enhances the conductivity and structural stability of silicon-based anodes, providing a viable route for large-scale production.