Micro-mesoporous carbon nanofibers loaded with sulfur as a self-supported cathode for high-performance Li-S batteries

Abstract

Self-supported carbon fibers with hierarchical porous structures regulated by zinc salt and copper salt were prepared through electrospinning technology, and sulfur loaded carbon fibers were obtained through sulfur vapor deposition method. Small molecular sulfur (S2-S4) and cyclic sulfur (S8) were encapsulated effectively in hierarchical pores by this way, both of them could run stably in carbonate electrolyte. Due to the three-dimensional conductive structure and suitable pore structure of the carbon fibers, the self-supported S/MCNF-ZnCu cathode exhibits high capacity, excellent cycling stability and out-standing rate capacity. The reversible capacity after 100 cycles at 0.2 A g−1 based on the mass of cathode is 520 mAh g−1, corresponding to the capacity retention rate of 98.4 %. The reversible capacity after 1000 cycles at 1.0 A g−1 is 429 mAh g−1, with a capacity loss of approximately 0.01 % per cycle. Even at the sulfur loading of 4 mg cm−2, the cathode shows a stable capacity of nearly 500 mAh g−1 at 0.1 A g−1, provides a novel and efficient strategy for the next generation of high-performance batteries.