Self-assembled graphene/sulfur composite as high current discharge cathode for lithium-sulfur batteries

Hydriodic acid and self-assembly approach are used to fabricate graphene wrapped sulfur composite. The self-assembly process of the relative "large" graphene sheet and "small" sulfur is quite controllable, and the sulfur particles are completely enfolded by RGO sheets with a unique stacked structure.The RGO/S composite with 80 wt.% sulfur shows an initial discharge capacity of 865.1 mAh g^-1 at 0.5 mA/cm². A high specific capacity of 720 mAh g^-1 with a coulombic efficiency of 95% is achieved after 50 cycles of charge/discharge. The material also delivered a capacity of more than 580 mAh g^-1 at 2 mA/cm² and can be recovered to 736 mAh g^-1 when the rate is returned to 0.2 mA/cm², representing a promising cathode material for high current discharge lithium-sulfur batteries.