▎ 摘　　要

NOVELTY - The method comprises adding an elemental sulfur solution in a graphene oxide dispersion to form a mixture or mixed solution, where: elemental sulfur particles are precipitated from a second solvent and attracted to a surface of each graphene sheets to form the sulfur-graphene composite material; the elemental sulfur solution comprises a first solvent and an elemental sulfur dissolved in the first solvent; the graphene dispersion comprises a second solvent and graphene sheets dispersed in the second solvent; and the elemental sulfur is insoluble in the second solvent. USE - The method is useful for making a sulfur-graphene composite material (claimed) that is useful as a cathode active material for lithium-sulfur battery. ADVANTAGE - The method simply and economically makes the sulfur-graphene composite material with good conductivity in an environmental friendly manner thus increasing capacity retention, charge-discharge performance, cycle life, capacity and energy efficiency of the lithium-sulfur battery. DETAILED DESCRIPTION - The method comprises adding an elemental sulfur solution in a graphene oxide dispersion to form a mixture or mixed solution, where: elemental sulfur particles are precipitated from a second solvent and attracted to a surface of each graphene sheets to form the sulfur-graphene composite material; the elemental sulfur solution comprises a first solvent and an elemental sulfur dissolved in the first solvent; the graphene dispersion comprises a second solvent and graphene sheets dispersed in the second solvent; and the elemental sulfur is insoluble in the second solvent, adding a reducing agent to the mixed solution to reduce the graphene oxide sheets to the graphene sheets to form the sulfur-graphene composite material, and separating the sulfur-graphene oxide composite material from the mixture. A concentration of the elemental solution is present 20-80 grams per liter. The graphene sheets are uniformly dispersed in the graphene dispersion, and a mass percentage of the graphene oxide sheets in the graphene oxide dispersion is 1-20 wt %. The method further comprises adding a surfactant in the graphene dispersion before the elemental sulfur solution is added. The elemental sulfur solution is dripped in the graphene dispersion. The sulfur-graphene composite material: is separated by leaching; and is air-dried or freeze-dried material. A diameter of the elemental sulfur particles is present in 20-200 nm. DESCRIPTION OF DRAWING(S) - The figure shows a flow chart of a method for making a sulfur-graphene composite material.