Micro-/mesoporous nature of carbon nanofiber/silica matrix as an effective sulfur host for rechargeable lithium–sulfur batteries

Abstract

Lithium–sulfur batteries are considered as promising candidate for next-generation electric vehicles due to their high-energy density and cyclability behaviour. However, the poor conductivity, large volumetric expansion of sulfur and dissolution of the intermediate polysulfides result in poor cyclic stability. Herein, sulfur–silica–carbon nanofiber (S–SiO2–CNF) based ternary composite cathode materials are prepared via simple heat treatment for lithium–sulfur batteries. The prepared materials are physically subjected to x-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, surface area and porosity analyses. The prepared S–SiO2–CNF cathode material exhibits an initial discharge capacity of 801 mAh g−1 at 0.2 C with a decay rate of 0.18% per cycle up to 300 cycles. The significantly enhanced electrochemical performance of the S–SiO2–CNF cathode is ascribed to the micro and mesoporous nature of prepared material and binding nature of silica, which restricting the volume changes of active material and limits the polysulfide dissolution.