Production of graphene nanoplatelets by oxidative anhydrous acidic media

Patent metadata

Field	Value
Publication number	US-9840418-B2
Application number	US-201514739455-A
Country	US
Kind code	B2
Filing date	Jun 15, 2015
Priority date	Jun 16, 2014
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

Methods of producing graphene nanoplatelets by exposing graphite to a medium to form a dispersion of graphite in the medium. In some embodiments, the exposing results in formation of graphene nanoplatelets from the graphite. In some embodiments, the medium includes the following components: (a) an acid; (b) a dehydrating agent; and (c) an oxidizing agent. In some embodiments, the methods of the present disclosure result in the formation of graphene nanoplatelets at a yield of more than 90%. In some embodiments, the methods of the present disclosure result in the formation of graphene nanoplatelets in bulk quantities that are more than about a 1 kg of graphene nanoplatelets. Additional embodiments of the present disclosure pertains to the formed graphene nanoplatelets. In some embodiments, the graphene nanoplatelets include a plurality of layers, such as from about 1 layer to about 100 layers.

First claim

What is claimed is:

1. A method of producing graphene nanoplatelets, wherein the method comprises:
exposing graphite to an anhydrous medium to form a dispersion of graphite in the medium, wherein the anhydrous medium comprises at least the following individual components:
(a) an acid,
(b) a dehydrating agent, and
(c) an oxidizing agent; and
wherein the exposing results in formation of the graphene nanoplatelets from the graphite.

2. The method of claim 1 , wherein the graphite is selected from the group consisting of graphite flakes, graphite powders, highly ordered pyrolytic graphite, graphite chunks, natural graphite, synthetic graphite, coal, stacks of graphene nanoribbons, and combinations thereof.

3. The method of claim 1 , wherein the graphite comprises graphite flakes.

4. The method of claim 1 , wherein the exposing comprises stirring the dispersion.

5. The method of claim 1 , wherein the exposing occurs at temperatures of about 5° C. to about 100° C.

6. The method of claim 1 , wherein the exposing occurs at room temperature.

7. The method of claim 1 , wherein the exposing occurs for about 1 minute to about 10 hours.

8. The method of claim 1 , wherein the anhydrous medium comprises a solution.

9. The method of claim 1 , wherein the acid is capable of intercalating with the graphite in the dispersion.

10. The method of claim 1 , wherein the acid comprises sulfuric acid.

11. The method of claim 1 , wherein the dehydrating agent is selected from the group consisting of oleum, sulfur trioxide, diphosphorus pentoxide and combinations thereof.

12. The method of claim 1 , wherein the dehydrating agent comprises sulfur trioxide.

13. The method of claim 1 , wherein the dehydrating agent comprises oleum.

14. The method of claim 13 , wherein the oleum has a free sulfur trioxide content of about 20% by weight of the oleum.

15. The method of claim 13 , wherein the anhydrous medium has a free sulfur trioxide content that ranges from about 0% to about 10% by weight of the anhydrous medium.

16. The method of claim 1 , wherein the oxidizing agent comprises a persulfate ion-containing compound.

17. The method of claim 16 , wherein the persulfate ion-containing compound comprises a persulfate ion selected from the group consisting of dipersulfate, peroxymonosulfate, hydrogen dipersulfate, hydrogen peroxymonosulfate, peroxydisulfuric acid, peroxymonosulfuric acid, and combinations thereof.

18. The method of claim 16 , wherein the persulfate ion-containing compound comprises a cation selected from the group consisting of ammonium, sodium, potassium, lithium, cesium, group 1 metals, group 2 metals, and combinations thereof.

19. The method of claim 1 , wherein the oxidizing agent comprises ammonium persulfate.

20. The method of claim 1 , wherein the acid:dehydrating agent:oxidizing agent weight ratio varies from about 1:1:1 to about 50:8:8.

21. The method of claim 1 , wherein the acid:dehydrating agent:oxidizing agent weight ratio is about 10:4:4.

22. The method of claim 1 ,
wherein the acid comprises sulfuric acid, and
wherein the dehydrating agent comprises oleum.

23. The method of claim 22 , wherein the oleum has a free sulfur trioxide content of about 20% by weight of the oleum.

24. The method of claim 22 , wherein the oxidizing agent comprises a persulfate ion-containing compound.

25. The method of claim 24 , wherein the persulfate ion-containing compound comprises ammonium persulfate.

26. The method of claim 22 , wherein the anhydrous medium has a free sulfur trioxide content that ranges from about 0% to about 10% by weight of the anhydrous medium.

27. The method of claim 1 , further comprising a step of terminating the formation of graphene nanoplatelets.

28. The method of claim 27 , wherein the terminating occurs for about 1 minute to about 180 minutes after exposing the graphite to the anhydrous medium.

29. The method of claim 27 , wherein the terminating occurs by quenching the dispersion with a quenching agent.

30. The method of claim 1 , wherein the method forms graphene nanoplatelets at a yield of more than 90%.

31. The method of claim 1 , wherein the method forms graphene nanoplatelets at a yield of about 100%.

32. The method of claim 1 , wherein the method forms graphene nanoplatelets in bulk quantities, wherein the bulk quantities are more than about 1 kg of graphene nanoplatelets.

33. The method of claim 1 , wherein the method forms graphene nanoplatelets in bulk quantities, wherein the bulk quantities range from about 1 g of graphene nanoplatelets to about 10 tons of graphene nanoplatelets.

34. The method of claim 1 , wherein the formed graphene nanoplatelets comprise a plurality of layers.

35. The method of claim 34 , wherein the formed graphene nanoplatelets comprise from about 1 layer to about 100 layers.

36. The method of claim 34 , wherein the formed graphene nanoplatelets comprise from about 10 layers to about 50 layers.

37. The method of claim 34 , wherein outer layers of the formed graphene nanoplatelets are oxidized, and wherein inner layers of the formed graphene nanoplatelets are non-oxidized.

38. The method of claim 1 , wherein the formed graphene nanoplatelets are non-oxidized.

39. The method of claim 38 , wherein the graphene nanoplatelets have an oxygen content of less than about 5% by weight of the graphene nanoplatelets.

40. The method of claim 1 , wherein the formed graphene nanoplatelets are optically transparent.

Assignees

• Tour James M
• Dimiev Ayrat
• Ceriotti Gabriel
• Univ Rice William M

Inventors

• Tour James M
• Dimiev Ayrat
• Ceriotti Gabriel

Classifications

• Y10T428/2991

  Coated · CPC title

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title

• C01B31/0476

  Chemistry & Metallurgy · mapped topic

• C01B31/0469 Primary

  Chemistry & Metallurgy · mapped topic

• C01B31/0438

  Chemistry & Metallurgy · mapped topic