Interfacially Enhanced Stability and Electrochemical Properties of C/SiOx Nanocomposite Lithium‐Ion Battery Anodes

Abstract

AbstractSilica is a promising anode material for high‐energy lithium‐ion batteries (LIBs), but it suffers from several problems. The main issue is low electrical conductivity, which limits its practical applications. Fabricating silica–carbon nanocomposites (C/SiO2) can significantly enhance the electrochemical performance of these materials. In this work, the authors perform first principles calculations to investigate the interfacial properties and electronic structure between carbon and small Si‐based molecules. The simulations suggest that C/SiO2 and C/SiO interfaces facilitate the lithiation process, providing additional lithium storage pathways in addition to the typical phase transitions of SiO2 and SiO. In addition, a simple production and ready to scale‐up method is proposed to fabricate a nanocomposite possessing rich C/SiOx (1 ≤ x ≤ 2) interfaces. The resulting nanocomposite anode has a stable capacity of ~650 mAh g‐1 at a current density of 1 A g‐1 after 1500 cycles with >95% capacity retention. This work provides a better understanding of the Li ion storage mechanisms of C/SiOx. Adding carbon not only increases electrical conductivity and strength, but also provides new pathways for Li‐ion transport through their interfaces contributing to the enhanced stability and electrochemical properties of inexpensive non‐conducting/oxide‐based energy storage materials.