Fabrication of silicon nanoparticles/porous carbon@porous carbon nanofibers core-shell structured composites as high-performance anodes for lithium-ion batteries

Silicon-based electrodes hold a great potential application in lithium-ion batteries (LIBs) due to the high-energy-density. However, huge volume expansion and poor electric conductivity hinder the commercial application of silicon-based materials. To alleviate these problems, two different hierarchical core-shell composites, silicon/[email protected] carbon nanofibers (Si/[email protected]) and [email protected] porous carbon nanofiber ([email protected]) are designed and prepared through coaxial electrospinning. The shell layer prevents silicon contacting with electrolyte directly, and the porous carbon nanofibers shorten Li+ diffusion distance and facilitate ion transport. Compared with [email protected] composites, Si/[email protected] composites achieve a better electrochemical performance owing to the high surface area (68.05 m2/g) and the fact that silicon nanoparticles are connected to each other by porous carbon in the core. The Si/[email protected] electrodes deliver a large reversible capacity (842.1 mAh∙g−1 after 500 cycles at 0.5 A∙g−1), a good rate capability (1366.6 mAh∙g−1 at 0.5 A∙g−1) and an excellent cycle stability (420.3 mAh∙g−1 at 2.0 A∙g−1 after 1000 cycles), indicating that it can be served as a promising anode for high-performance LIBs.