Preparation and electrochemical performance of a graphene-wrapped carbon / sulphur composite cathode

Graphene is used as a barrier film to suppress the “shuttle effect ”and to improve the performance of activated carbon-sulphur hybrid cathode materials in a lithium-sulphur battery by forming a core-shell structure. Graphene wraps around the activated carbon-sulphur hybrid to form a core-shell structure, in which the porous carbon framework stores most of the sulphur and the graphene layer suppresses the movement of the soluble polysulfide in the electrolyte during charge-discharge, resulting in an improvement of capacity and cyclic stability during long-term cycling. Such a core-shell structure is formed by changing the hydrophilicity of graphene oxide during reduction, in which the hydrophobic graphene closely wraps around the hydrophobic carbon surface.