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.