Enhanced electrochemical performance by wrapping graphene on carbon nanotube/sulfur composites for rechargeable lithium-sulfur batteries

A novel graphene-wrapped carbon nanotube/sulfur structure was designed to improve the electrochemical performance of the lithium-sulfur (Li-S) batteries. Owing to the introduction of the reduced graphene oxide (rGO) with the aim to restrain the polysulfide anions diffusion phenomenon, increase the overall electronic conductivity of the electrode and accommodate volume expansion between the delithiated S and lithiated Li2S phases, the resulted graphene-wrapped carbon nanotube/sulfur (S/CNT@rGO) composite makes the cycling performance of the Li-S batteries better than that without rGO. The S/CNT@rGO composite showed an initial discharge capacity of similar to 1299 mA h g(-1) at 0.2 C rate. After 100 cycles of charge/discharge, the S/CNT@rGO composite retained a high specific capacity of similar to 670 mA h g(-1), much higher than that without rGO ( < 150 mA h g(-1)). The results show that the graphene-wrapped carbon nanotube/sulfur composite could be a promising cathode material for high-rate performance Li-S batteries. (C) 2014 Elsevier B.V. All rights reserved.