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

•Researched self-assembled graphene /sulfur composite for lithium-sulfur batteries.•Sulfur content up to 80% is loaded in hydriodic acid reduced graphene oxide.•The composite shows high specific capacity and enhanced rate capability.•Both stacked structure and the conductive RGO support enable high-rate capability.

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.

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