In Situ Mesopore Formation in SiOx Nanoparticles by Chemically Reinforced Heterointerface and Use of Chemical Prelithiation for Highly Reversible Lithium‐Ion Battery Anode

Abstract SiO x is a promising next‐generation anode material for lithium‐ion batteries. However, its commercial adoption faces challenges such as low electrical conductivity, large volume expansion during cycling, and low initial Coulombic efficiency. Herein, to overcome these limitations, an eco‐friendly in situ methodology for synthesizing carbon‐containing mesoporous SiO x nanoparticles wrapped in another carbon layers is developed. The chemical reactions of vinyl‐terminated silanes are designed to be confined inside the cationic surfactant‐derived emulsion droplets. The polyvinylpyrrolidone‐based chemical functionalization of organically modified SiO 2 nanoparticles leads to excellent dispersion stability and allows for intact hybridization with graphene oxide sheets. The formation of a chemically reinforced heterointerface enables the spontaneous generation of mesopores inside the thermally reduced SiO x nanoparticles. The resulting mesoporous SiO x ‐based nanocomposite anodes exhibit superior cycling stability (≈100% after 500 cycles at 0.5 A g −1 ) and rate capability (554 mAh g −1 at 2 A g −1 ), elucidating characteristic synergetic effects in mesoporous SiO x ‐based nanocomposite anodes. The practical commercialization potential with a significant enhancement in initial Coulombic efficiency through a chemical prelithiation reaction is also presented. The full cell employing the prelithiated anode demonstrated more than 2 times higher Coulombic efficiency and discharge capacity compared to the full cell with a pristine anode.