Silicon nanoparticles encapsulated in multifunctional crosslinked nano-silica/carbon hybrid matrix as a high-performance anode for Li-ion batteries

Abstract

• A novel multifunctional nano-silica/carbon hybrid matrix is designed to encapsulate Si nanoparticles in the coating layer. • The n-SiO 2 /C layer is applied to enhance the conductivity, hold the structural integrity, and provides a higher capacity. • The Si-2@n-SiO 2 /C composites demonstrate ideal cycle stability as anode material for lithium-ion batteries. The application of silicon as anode materials for lithium-ion batteries is limited by the huge volumetric expansion and complex synthesis processes. Herein, silicon nanoparticles encapsulated in multifunctional crosslinked nano-silica/carbon hybrid matrix (Si@n-SiO 2 /C) composites are successfully synthesized via simultaneous condensation copolymerization between (3-aminopropyl)-triethoxysilane (APTES) and L-ascorbic acid (L-AA). With the introduction of nano-silica, the multifunctional nano-silica/carbon hybrid matrix can significantly maintain structural integrity during the volume change of silicon, provide a higher capacity than the traditional single carbon coating layer and enhance the conductivity of the materials. Correspondingly, the obtained Si-2@n-SiO 2 /C composites display quite outstanding cycle stability and superior structural integrity maintenance, which delivers a capacity of 800.7 mAh g −1 after 300 cycles at the current density of 1 A g −1 . Such a novel coating layer structure design and simultaneous growth of nano-silica/carbon hybrid matrix layer on silicon nanoparticles will provide a simple synthesis strategy for manufacturing high-performance Si-based anode materials.