Improved Self-Assembled Silicon-Based Graphite Composite Anodes for Commercially Viable High-Energy-Density Lithium-Ion Batteries

Abstract

Silicon-based anode materials are used to improve the performance of next-generation high-energy-density lithium-ion batteries (LIBs). However, the inherent limitations and cost of these materials are hindering their mass production. Commercial graphite can overcome the shortcomings of silicon-based materials and partially reduce their cost. In this study, a high-performance, low-cost, and environmentally friendly composite electrode material suitable for mass production was developed through optimizing the silicon content of commercial silicon-graphite composites and introducing a small amount of graphene and carbon nanofibers. This partially overcomes the inherent limitations of silicon, enhances the interface stability of silicon-based materials and the cycle stability of batteries, and reduces the irreversible capacity loss of the initial cycle. At a silicon content of 15 wt%, the initial Coulombic efficiency (ICE) of the battery was 65%. Reducing the silicon content in the composite electrode from 15% to 10% increased the ICE to 70% and improved the first lithiation and delithiation capacities. The battery exhibited excellent cycle stability at a current density of 0.1 A g-1, retaining approximately 65% of its capacity after 100 cycles, good performance at various current densities (0.1-1 A g-1), and an excellent reversible performance.