Self-Supporting Silicon-Based Hierarchical Carbon Nanofibers As Anodes for Lithium-Ion Batteries

Abstract

Si-based anodes have demonstrated significant potential for application in lithium-ion batteries (LIBs) owing to their high-energy density. Nevertheless, commercial application of Si-based anodes is hindered by their substantial volume expansion and poor conductivity. In this paper, a straightforward, efficient, and environmentally friendly method was proposed to prepare self-supporting Si-based hierarchical carbon nanofibers (Si@SiO x / HPCNFs) derived from coaxial electrospun nanofibers as high-performance anodes for LIBs. By introducing an oxide layer onto the surface of Si nanoparticles (NPs), the swelling of Si during charging and discharging was alleviated, and sufficient hydrogen bonds and active sites were provided for the adequate binding between Si@SiO x and precursors. Meanwhile, the hierarchical porous structure of carbon nanofibers (CNFs) provided sufficient space for the swelling of Si NPs in their core layer, and the shell layer of CNFs had a barrier effect to prevent direct contact between the electrolyte and Si NPs, thus facilitating Li + transport and ensuring the cyclic stability of the material. Accordingly, the Si@SiO x /HPCNF anode demonstrated a large reversible capacity (686.0 mAh g −1 ) after 100 cycles at 100 mA g −1 and retained its original fiber structure well, suggesting that the self-supporting Si@SiO x /HPCNF anode has great potential in advanced energy storage.