Nanostructured Porous Si/C Composite as an Advanced Anode Material for Li-Ion Batteries

Abstract

This study presents the development of a novel silicon–carbon (Si/C) hybrid composite as a negative electrode material for lithium-ion batteries, along with a cost-effective and scalable synthesis route. The composite is synthesized through high-energy mechanical milling of silicon nanoparticles with amorphous silica to form a Si/SiO₂ intermediate, which is subsequently coated with a preceramicpolymer and pyrolyzed to yield a Si/SiO₂/SiOC composite. In an alternative method, a carbon-rich phenolic resin is employed in place of the polymer-derived ceramic precursor, resulting in a Si/SiO₂/C composite. In both synthesis pathways, selective removal of the SiO₂ phase using hydrofluoric acid produces a porous Si/C hybrid architecture. The resulting material effectively mitigates the volumetric expansion of silicon during electrochemical cycling, leading to significantly improved capacity retention and cycling stability compared to conventional graphite anodes. Moreover, the strategy minimizes side reactions, enhances battery lifespan, and offers a simplified, energy-efficient fabrication process with highermaterialyield, thereby demonstrating strong potential as a next generation anode material for advanced lithium-ion battery systems. The optimum composites delivered722 mAhg⁻1 a er 100 charge-discharge cycles at a current density of 0.1 A g⁻1, thereby rendering it a suitable anode material for lithium-ion battery applications.