Construction of porous carbon nanofibers with encapsulated sulfur as free-standing cathode material of lithium-sulfur batteries

Carbon material is regarded as an ideal cathode material carrier for lithium-sulfur (Li–S) batteries. Reasonably designing the structure of carbon host plays the key role to alleviate the shuttle effect of polysulfide and improve specific capacity and cycle stability of Li–S batteries. Herein, a free-standing host consists of porous carbon nanofibers (PCNFs) has been prepared by electrospinning technology using zinc acetate as pore-forming agent, which was directly applied as cathode material for Li–S battery after sulfur encapsuled (47.8 wt% sulfur content). The obtained sulfur cathode exhibits charge and discharge capacities of 744 and 726 mAh g−1 at 0.1 C (1 C = 1675 mA g−1) after 150 cycles and possesses a low capacity decay rate (0.09%) during each cycle. The good electrochemical properties of sulfur cathode can be ascribed to the presence of PCNFs free-standing substrate, which offers abundant pores to accommodate sulfur and inhibits the shuttle effect of polysulfide.