High‐Performance Silicon Anodes Enabled by Multifunctional Ultrafine Silica Nanoparticle‐Embedded Carbon Coatings for Lithium‐Ion Batteries

Abstract

Abstract Silicon (Si) holds immense promise as viable anode for next‐generation high‐energy‐density Li‐ion batteries (LIBs). However, its poor ionic/electronic conductivity and significant volumetric changes during cycling lead to rapidly deteriorated LIB performance. Here, a novel multifunctional coating featuring ultrafine SiO 2 nanoparticles (<7 nm) embedded carbon on Si nanoparticles (termed Si@uSiO 2 ‐C) to resolve these challenges is proposed. This unique uSiO 2 ‐C coating provides high‐efficient electron and ion transport pathways, while also improves interfacial stability and mitigates volume changes during cycling, thereby enhancing the conductivity and structural integrity of Si@uSiO 2 ‐C, as corroborated by extensive experimental and computational studies. In addition, the abundant interfaces in uSiO 2 ‐C coating facilitate Li + transport and the evenly distributed ultrafine SiO 2 nanoparticles impart high electrochemical reactivity and mechanical robustness. Consequently, the Si@uSiO 2 ‐C anode achieves a high reversible capacity of 2093 mAh g −1 at 0.2 A g −1 , with a high initial Coulombic efficiency of 88.3%, superior rate capability and durability (1000 cycles, 928 mAh g −1 at 1.0 A g −1 , 75% capacity retention). Full cells paired with commercial LiFePO 4 cathodes demonstrate high cyclability, maintaining 80% capacity retention over 500 cycles at 4 C. This work highlights the vital role of multifunctional coating in promoting the electrochemical performance of Si‐based anodes for high‐performance LIBs.