Study on the Preparation of Si/C Composite Materials with Mixed Structures by Open Mill Method and Their Lithium Storage Performance

Abstract The advantage of ultra-high theoretical capacity of silicon materials has attracted significant attention in the field of lithium battery anodes, but the rapid capacity decay caused by large volume changes during cycling limits its practical use. In this study, a multi-layer composite Si/C anode material was prepared using nano-silicon, graphite, multi-walled carbon nanotubes, and asphalt as raw materials through a process combining twin-roll milling and high-temperature carbonization. Test results showed that the initial discharge specific capacity of the sample was 1682.31 mAh g⁻¹, and the capacity retention after 200 cycles at 1 A g⁻¹ was as high as 70%. Microscopic analysis demonstrated that graphite and multi-walled carbon nanotubes could build a continuous three-dimensional conductive framework, and the interlayer voids could buffer the volume expansion of silicon; electrochemical tests confirmed that the composite structure could effectively enhance reversible capacity and suppress cycle decay. This preparation process is simple, the raw materials are readily available, and it is easy to industrialize and promote, providing a new approach for the large-scale preparation of high-performance silicon-carbon anodes.