Si/C Graphite Anode Materials for Lithium-Ion Batteries with Stabilized Capacity and High-Compacted Density Prepared by Liquid-Phase Method

Abstract

Silicon has an ultra-high theoretical specific capacity, making it an ideal material to replace traditional graphite anodes. However, the volume expansion of silicon leads to its poor cycling stability. In this work, a high-compacted density silicon-carbon anode (PMMA@Si/C) is presented. The structure of poly(methyl methacrylate) (PMMA) mixed with silicon creates a pre-positioned space on the graphite surface, providing room for expansion during silicon cycling. It was also blended with commercial graphite and after carbonization of the surface, a carbon layer was formed using a asphalt coating. At a current density of 0.1 C, the PMMA@Si/C anode has a capacity retention rate of 72.8% after 300 cycles. The compacted density of PMMA@Si/C is 1.65 g/cm 3 , which is close to that of commercial graphite negative electrodes. And it has excellent rate performance. The preparation method is simple and suitable for mass production. The developed PMMA@Si/C is a promising commercial anode.