Methods for manufacturing graphene based material
A method for manufacturing graphene-based material is disclosed. A graphene oxide dispersion includes graphene oxide dispersed in solvent. A hydrogen sulfide gas is introduced to the graphene oxide dispersion at a reacting temperature to achieve a graphene dispersion. The hydrogen sulfide reduces graphene oxide into graphene, and elemental sulfur produced from the hydrogen sulfide is deposited on surfaces of the graphene. The solvent and elemental sulfur are removed to achieve a graphene composite material.
1. A method for manufacturing graphene based material comprising:
providing a graphene oxide dispersion comprising graphene oxide dispersed in solvent;
directly introducing a hydrogen sulfide gas to the graphene oxide dispersion at a redox reacting temperature to create a graphene dispersion, the graphene dispersion created by a redox reaction between the graphene oxide and the hydrogen sulfide gas, wherein the hydrogen sulfide reduces the graphene oxide into graphene, and elemental sulfur produced from the hydrogen sulfide is deposited on surfaces of the graphene;
solvothermal reacting the graphene dispersion to achieve a graphene-based gel comprising a three dimensional porous graphene macrostructure and elemental sulfur deposited on surfaces and pores of the three dimensional porous graphene macrostructure, with the three dimensional porous graphene macrostructure being a free-standing structure; and
removing the solvent to achieve the graphene based material.
2. The method of claim 1 , wherein the redox reacting temperature ranges from about 5° C. to about 260° C.
3. The method of claim 1 , wherein removing the solvent comprises freeze-drying the graphene dispersion.
4. The method of claim 1 , wherein before the solvothermal reacting, sulfur dioxide gas introduced into the graphene dispersion, forms elemental sulfur on the surfaces of the graphene.
5. The method of claim 1 , wherein the solvent is removed by at least one of:
evaporating solvent from the graphene dispersion at room temperature;
vacuum heating the solvent;
heating the solvent at atmospheric conditions, being in a protective gas, and supercritical drying.
6. The method of claim 1 , wherein selecting the solvent comprises selecting a solvent from a group consisting of water, ethanol, isopropanol, ethylene glycol, N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, and combinations thereof.
7. The method of claim 1 , wherein a graphene oxide concentration in the graphene oxide dispersion ranges from about 0.05 mg/mL to about 30 mg/mL.
8. The method of claim 1 , further comprising the solvothermal reacting being processed at a temperature ranging from about 50° C. to about 360° C. for about 0.1 hours to about 120 hours.
9. The method of claim 1 , further comprising removing the elemental sulfur from the graphene surface, by removing the elemental sulfur using a thermal treatment at a temperature from about 150° C. to about 1000° C. that evaporates the elemental sulfur from the surface of the graphene.
10. The method of claim 1 , further comprising:
using an organic liquid for removing the elemental sulfur from the surface of the grapheme by dissolving the elemental sulfur on the surface of the grapheme.
11. The method of claim 10 , wherein the organic liquid used to remove the elemental sulfur from the surface of the grapheme is selected from a group consisting of carbon disulfide, carbon tetrachloride, benzene, toluene, and combinations thereof.
12. The method of claim 1 , wherein a mass percentage of the elemental sulfur on the surface of the grapheme is maintained between 5% to 95% by controlling the introduction of hydrogen sulfide gas.
13. The method of claim 1 , wherein a pore volume of the three dimensional porous graphene macrostructure is in a range of 0.05 cm3/g to 5.2 cm3/g.
14. The method of claim 13 , wherein a pore size distribution is in a range from 0.4 nm to 10 μm.