Vesicle-like sulfur/reduced graphene oxide composites for high performance lithium-sulfur batteries

摘要

Although Li-sulfur (Li-S) battery has the potential to be the next generation energy storage devices, it still encounters with challenges such as poor conductivity, serious shuttle effects and huge volume expansion. To address the aforementioned issues, a vesicle-like sulfur/reduced graphene oxides composite cathode with a high sulfur content of 76 wt% has been synthesized. For the composite, graphene sheets derived vesicle shells can improve the conductivity to facilitate fast electron transfer in cathode. Meanwhile, the unique vesicle structure can not only suppress the dissolution of polysulfides into the electrolyte but also mitigate the volumetric variation of polysulfide species during cycling. On the basis of these merits, the composite delivers superior electrochemical performances. A relatively stable capacity of over 600 mAh g(-1) is remained during 150 cycles at 2 C. Even with 300 cycles, it still shows an extremely low decay of approximately 0.12% per cycle. Our work provides a strategy for the preparation of a kind of sulfur@graphene material that holds a great potential for high performance Li-S batteries. (C) 2017 Elsevier B.V. All rights reserved.