Si/C composites based on bubble 3D graphene-like porous materials as self-supporting anodes for high-performance lithium-ion batteries

Abstract

Silicon (Si)-based anode materials are promising for lithium-ion batteries (LIBs) due to their high theoretical capacity, but challenges such as large volume changes during cycling and low conductivity hinder their practical application. In this study, we report a self-supporting, binder-free Si/C composite anode featuring structurally continuous, three-dimensional (3D) graphene-like silicon thin films, encapsulated by a 3D carbon film framework and coated with an amorphous carbon layer. This architecture is specifically designed to mitigate the volume expansion of silicon during cycling and enhance electrical conductivity. The spacing between the carbon films is systematically controlled by applying varying pressure compressions, allowing us to evaluate its effect on limiting the volume expansion of Si. At a current density of 1 A g^-1, the C@Si@CPGN-3MPa anode exhibits an initial coulombic efficiency (ICE) of 84.08 %, a stable specific capacity of 825.3 mAh g^-1, and excellent long-term cycling stability. This work provides valuable insights into the design of self-supporting Si-based anodes that offer long cycle life, high energy density, and enhanced structural stability, which are crucial for advancing the practical application of Si in LIBs.