Ionic liquid-assisted pickering emulsion synthesis of hierarchical porous carbon wrapped graphene nanosheets for high performance lithium-sulfur batteries

摘要

Graphene-based nanocomposites with unique two-dimensional (2D) structural feature have become the most potential candidate for energy storage systems due to the excellent electrical conductivity and large specific surface area of graphene sheets. However, the aggregation of graphene nanosheets inhibits their applications in lithium-sulfur batteries. Here we tackle this problem by designing a porous carbon wrapped graphene nanosheet (M-GN) via a facile IL-microemulsion method. During the Pickering emulsion process, graphene oxide (GO) serves as surfactant and the templates, while the hydrophobic ionic liquid ([BMIm][FeCl4]) stabilizes the GO and forms the emulsion environment. The electrostatic effect between negative graphene oxide (GO) and positive cation 1-butyl-3-methylimidazolium (BMIm(+)) helps to form a stabilized system, which can facilitate the uniform growth of the carbon layers on GO. The obtained S/M-GN cathode delivers a high discharge capacity of 1331 mA h g(-1) at 0.1C and 757 mA h g(-1) after 100 cycles at 0.5C. The innovative IL-microemulsion method provides us with a new avenue for the synthesis of effective materials for energy storage devices. (C) 2019 Elsevier B.V. All rights reserved.