Nano-carbon/sulfur composite cathode materials with carbon nanofiber as electrical conductor for advanced secondary lithium/sulfur cells

A carbon particle supported sulfur (C–S) composite cathode material was prepared by a chemical deposition method in an aqueous solution. The performance of the C–S cathode material with carbon particles (CP) and carbon nanofibers (CNFs) as electrical conductors and CMC + SBR as binder was evaluated in Li/S cells using cyclic voltammetry, constant current cycling, and electrochemical impedance spectroscopy. The C–S material and the electrodes were examined by scanning electron microscopy. It is found that the C–S cathode with CNFs shows improvement of not only discharge capacity but also cycling durability. It exhibits an initial discharge capacity of 1200 mAh g−1, or 72% of theoretical, and retains 668 mAh g−1, or 40% of the sulfur theoretical capacity after 50 cycles. The C–S electrode with CNFs has a three-dimensional network structure with regular pores, which can suppress the agglomeration of sulfur or lithium sulfide. Thus, the cell performance is improved.

► New simple solution preparation of sulfur–carbon nanoparticles.
► Stabilization of the sulfur electrode structure using carbon nanofibers.
► Improved cycling stability resulting from combination of sulfur–carbon nanoparticles with carbon nanofibers.