Recent progress in utilizing carbon nanotubes and graphene to relieve volume expansion and increase electrical conductivity of Si-based composite anodes for lithium-ion batteries

Si has received considerable attention as a high-capacity anode for lithium-ion batteries (LIBs) because of its advantages such as high theoretical specific capacity, low working potential, and abundant sources. However, Si undergoes a large volume change during lithiation/delithiation, which is restricts the commercialization of Si anodes. CNTs and graphene have received considerable attention as functional carbonaceous materials that can overcome these shortcomings because of their excellent mechanical strength and electrical conductivity. In this article, we review studies on the use of CNTs and graphene as Si/C composite electrodes in LIBs conducted over the past five years (2019-2023). We also summarize the roles of CNTs and graphene in Si/C composites and discuss the issues to be considered for commercializing Si/C composites as anodes for LIBs. Further, we review the processing methods, performances, and mass-production possibilities of various Si/C composites that use CNTs and graphene. We hope that this study will help establish research directions for commercializing Si/C composites supported by CNTs and graphene.