Silicon Nanoparticles Encapsulated within Multifunctional Double Carbon Matrices as Anodes for High‐Performance Lithium‐Ion Batteries

Abstract

Significant volume expansion and limited electrical conductivity pose substantial challenges to the practical application of silicon (Si). Herein, silicon nanoparticles are incorporated into a dual‐carbon matrix co‐doped with nitrogen and sulfur (N/S co‐doped Si/G/C) using a method that combines ball milling and carbonization. The Si nanoparticles are uniformly distributed between graphite layers and encapsulated by an amorphous carbon layer co‐doped with N/S generated from the pyrolysis of pitch and thiourea. This N/S co‐doped three‐dimensional dual‐carbon structure not only effectively mitigates the volume expansion of silicon but also significantly enhances the material's ionic and electronic conductivity. Even at a current density of 1 A g −1 , the capacity remains at 625.87 mAh g −1 after 500 cycles, demonstrating exceptional cycling stability. When assembled into a full battery with LiFePO 4 , the battery retains a capacity of 158.9 mAh g −1 after 200 cycles, corresponding to a retention of 95.6%. In addition, the method is simple to operate, highly adaptable and versatile in function, and does not involve any toxic or harmful chemical substances, providing a new idea for the industrial production of silicon–carbon anode materials.