Method for making sulfur-graphene composite material

Abstract

A method for making a sulfur-graphene composite material is provided. In the method, an elemental sulfur solution and a graphene dispersion are provided. The elemental sulfur solution includes a first solvent and an elemental sulfur dissolved in the first solvent. The graphene dispersion includes a second solvent and graphene sheets dispersed in the second solvent. The elemental sulfur solution is added to the graphene dispersion, a number of elemental sulfur particles are precipitated and attracted to a surface of the graphene sheets to form the sulfur-graphene composite material. The sulfur-graphene composite material is separated from the mixture.

What is claimed is: 
     
         1 . A method for making a sulfur-graphene composite material comprising:
 providing an elemental sulfur solution and a graphene dispersion, the elemental sulfur solution comprising a first solvent and an elemental sulfur dissolved in the first solvent, the graphene dispersion comprising a second solvent and a plurality of graphene sheets dispersed in the second solvent, the elemental sulfur being insoluble in the second solvent;   adding the elemental sulfur solution in the graphene dispersion to form a mixture, a plurality of elemental sulfur particles being precipitated from the second solvent and attracted to a surface of the plurality of graphene sheets to form the sulfur-graphene composite material; and   separating the sulfur-graphene composite material from the mixture.   
     
     
         2 . The method of  claim 1 , wherein the first solvent is selected from the group consisting of carbon disulfide, carbon tetrachloride, benzene, toluene, and any combination thereof. 
     
     
         3 . The method of  claim 1 , wherein a concentration of the elemental solution is about 20 grams per liter to about 80 grams per liter. 
     
     
         4 . The method of  claim 1 , wherein the plurality of graphene sheets are uniformly dispersed in the graphene dispersion, and a mass percentage of the plurality of graphene sheets in the graphene dispersion is in a range from about 0.1 wt % to about 10 wt %. 
     
     
         5 . The method of  claim 1 , wherein the second solvent is selected from the group consisting of water, methanol, ethanol, ether, and any combination thereof. 
     
     
         6 . The method of  claim 1  further comprising adding a surfactant in the graphene dispersion before the elemental sulfur solution is added. 
     
     
         7 . The method of  claim 6 , wherein the surfactant is selected from the group consisting of sorbitan oleate or sorbitan (Z)-mono-9-octadecenoate, octylphenolpoly(ethyleneglycolether) x , x=9-10, tetrahydrofuran, and any combination thereof. 
     
     
         8 . The method of  claim 1 , wherein the elemental sulfur solution is dripped in the graphene dispersion. 
     
     
         9 . The method of  claim 1 , wherein the sulfur-graphene composite material is separated by leaching. 
     
     
         10 . The method of  claim 1 , wherein the sulfur-graphene composite material separated is air-dried or freeze-dried. 
     
     
         11 . The method of  claim 1 , wherein the plurality of elemental sulfur particles in the sulfur-graphene composite material are attracted to the surface of each graphene sheet 
     
     
         12 . The method of  claim 1 , wherein a diameter of the plurality of elemental sulfur particles is in a range from about 20 nanometers to about 200 nanometers. 
     
     
         13 . A method for making a sulfur-graphene composite material comprising:
 providing an elemental sulfur solution and a graphene oxide dispersion, the elemental sulfur solution comprising a first solvent and an elemental sulfur dissolved in the first solvent, the graphene dispersion comprising a second solvent and a plurality of graphene oxide sheets dispersed in the second solvent; the elemental sulfur being insoluble in the second solvent;   adding the elemental sulfur solution in the graphene oxide dispersion to form a mixed solution, a plurality of elemental sulfur particles being precipitated from the second solvent and attracted to a surface of the plurality of graphene oxide sheets to form the sulfur-graphene oxide composite material;   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 composite material from the mixed solution.   
     
     
         14 . The method of  claim 13 , wherein the first solvent is selected from the group consisting of carbon disulfide, carbon tetrachloride, benzene, toluene, and any combination thereof. 
     
     
         15 . The method of  claim 13 , wherein the second solvent is selected from the group consisting of water, methanol, ethanol, aether, and any combination thereof. 
     
     
         16 . The method of  claim 13 , wherein the reducing agent is selected from the group consisting of sodium borohydride, hydrazine hydrate, ascorbic acid, formaldehyde, hydroiodic acid, hydrobromic acid, and any combination thereof. 
     
     
         17 . The method of  claim 13 , wherein a mass percentage of the graphene oxide sheets in the graphene oxide dispersion is in a range from about 1 wt % to about 20 wt %.