N-Doped Graphene Sheet Encapsulated Sulfur Binary Composite as Cathode for Lithium-Sulfur Battery Applications

Herein, sulfur-/nitrogen-doped graphene (SNG) binary composite has been prepared by melt diffusion method and employed as cathode material for lithium-sulfur (Li-S) battery. The physical and electrochemical performances of prepared SNG binary composite were characterized using x-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, cyclic voltammetry and galvanostatic charge–discharge test. The SNG cathode delivers a high initial discharge capacity of 1135 mAh g−1, and it sustains the capacity of 687 mAh g−1 over the 50th cycle at 0.1C rate. The good electrochemical performance of SNG cathode is accredited to N-doping in graphene, which provides faster charge transfer pathway and suppresses the shuttle effect of polysulfides. The present study determines that the prepared SNG composite is a suitable material for cathode in Li-S battery application.