Graphene-wrapped CoS nanoparticles for high-capacity lithium-ion storage.

Graphene-wrapped CoS nanoparticles are synthesized by a solvothermal approach. The product is significantly different from porous CoS microspheres prepared in the absence of graphene under similar preparation conditions. The CoS microspheres and CoS/graphene composite are fabricated as anode materials for lithium-ion batteries. The CoS/graphene composite is found to be better suitable as an anode in terms of higher capacity and better cycling performances. The nanocomposite exhibits an unprecedented high reversible capacity of 1056 mA h/g among all cobalt sulfide-based anode materials. Good cycling performances are also observed at both small and high current rates.