Method for making sulfur-graphene composite material

1. A method for making sulfur-graphene composite material comprising steps:

providing a dispersed solution comprising a solvent and a plurality of graphene sheets dispersed in the solvent;

dissolving a sulfur-source chemical compound into the dispersed solution to form a mixture; and

forming the sulfur-graphene composite material in the solvent by producing elemental sulfur on a surface of the plurality of graphene sheets due to a redox reaction between the sulfur-source chemical compound and the reactant, by introducing a reactant according to the sulfur-source chemical compound into the mixture; and

separating the sulfur-graphene composite material from the solvent.

2. The method of claim 1 , wherein the sulfur-source chemical compound is selected from the group consisting of thiosulfates, thiocarbonates, sulfites, metal sulfides (M x S y ), sulfur dioxide, sulfur trioxide, hydrogen sulfide, thiosulphuric acid, thiocarbonic acid, sulfurous acid, and combinations thereof.

3. The method of claim 2 , wherein the thiosulfates are selected from the group consisting of sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, and combinations thereof.

4. The method of claim 3 , wherein the reactant is selected from the group consisting of hydrochloric acid, oxalic acid, acetic acid, nitric acid, and combinations thereof.

5. The method of claim 2 , wherein the metal sulfide is selected from the group consisting of sodium sulfide, potassium sulfide, lithium sulfide, and combinations thereof.

6. The method of claim 5 , wherein the reactant is selected from the group consisting of sulfur dioxide, sulfur trioxide, and combinations thereof.

7. The method of claim 1 , wherein the reactant is an oxidant or reductant of the sulfur-source chemical compound.

8. The method of claim 1 , wherein the reactant is an agent to induce a disproportionation reaction of the sulfur-source chemical compound.

9. The method of claim 1 , wherein the separating step comprises a step of centrifugalizing or filtrating the sulfur-graphene composite material from the solvent.

10. The method of claim 1 , wherein during the separating step, the plurality of graphene sheets are self-assembled to form a stable stacked structure, the stable stacked structure comprises a plurality of graphene sheets stacked and stably combined together, and a plurality of elemental sulfur particles uniformly located between adjacent layers of graphene sheets.

11. The method of claim 1 , wherein the elemental sulfur is combined with the surface of the plurality of graphene sheets through a π bond.

12. The method of claim 1 , wherein a particle size of the elemental sulfur is in a range from about 10 nanometers to about 1 micron.

13. The method of claim 1 , wherein the plurality of graphene sheets comprises graphene oxides.

14. The method of claim 13 , wherein hydrogen sulfide is formed to reduce the graphene oxides into unoxidized graphene sheets when introducing the reactant.

15. The method of claim 14 , wherein the elemental sulfur is combined with the unoxidized graphene sheets by carbon-sulfur bonds.

16. A method for making sulfur-graphene composite material comprising steps:

providing a dispersed solution comprising a solvent and a plurality of graphene oxide sheets dispersed in the solvent;

dissolving a sulfur-source chemical compound into the dispersed solution to form a mixture; and

introducing a reactant to the mixture to produce elemental sulfur and hydrogen sulfide due to one redox reaction between the sulfur-source chemical compound and the reactant;

reducing the graphene oxide sheets into unoxidized graphene sheets by the hydrogen sulfide produced by the redox reaction, to achieve the sulfur-graphene composite material in the solvent; and

separating the sulfur-graphene composite material from the solvent.

17. The method of claim 16 , wherein the elemental sulfur is combined with the unoxidized graphene sheets by carbon-sulfur bonds.