Synthesis and research of layered CoS/graphene nanoflakes as sulfur cathode for high-energy lithium sulfur batteries

In this work, CoS nanofiakes were directly grown on graphene followed by sulfur storing by annealing sulfur/carbon disulfide and CoS nanoflakes at 155 degrees C for 10 h in N-2. The microstructural and morphologies of the CoS/ graphene nanoflake composites (CoS/G) were investigated by X-ray diffraction/photoelectron spectroscopy and electron microscopy. Benefiting from the strong chemical binds between CoS and lithium polysulfide species, and good electrical conductivity of graphene, the nanostructured sulfur cathode displays high sulfur utilization, promising rate capability and cycling stability compared to pristine sulfur cathode. The discharge capacity of the 100th cycle is maintained at 675.7 mA h g(-1) at 0.5C.