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/cm(2). 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/cm(2) and can be recovered to 736 mAh g (1) when the rate is returned to 0.2 mA/cm(2), representing a promising cathode material for high current discharge lithium-sulfur batteries. (C) 2015 Elsevier Ltd. All rights reserved.