Graphene and carbon nanotube compositions
View Patent ↗Compositions having carbon nanotubes and two or more graphene sheets are disclosed. The carbon nanotubes can be interposed between the graphene sheets within the composition. Applicants have surprisingly found that, in some embodiments, these compositions exhibit superior absorbent and/or electrical properties. The present application also includes methods of making and using these compositions, and capacitors including these compositions.
1. A composition comprising two or more graphene sheets, wherein the two or more graphene sheets are functionalized with a first negatively charged group;
carbon nanotubes disposed between the two or more graphene sheets, wherein the carbon nanotubes are functionalized with a second negatively charged group;
wherein a weight ratio of the two or more graphene sheets to the carbon nanotubes is in the range of 1/5 to 5/1; and
wherein the composition further comprises an ammonium ion or a substituted ammonium ion disposed between the two or more graphene sheets.
2. The composition of claim 1 , wherein a net electrical charge of the two or more graphene sheets and the carbon nanotubes is negative.
3. The composition of claim 1 , wherein at least one of the first and second negatively charged groups are a free acid of a group that comprises a carboxyl group, a boronic acid group, a phosphonic acid group, or a sulfamic acid group.
4. The composition of claim 1 , further comprising an anionic surfactant and a cationic surfactant, wherein the anionic surfactant and the cationic surfactant are disposed between the two or more graphene sheets.
5. The composition of claim 4 , wherein the cationic surfactant is selected from the group of octenidine dihydrochloride, cetylpyridinium chloride (CPC), polyethoxylated tallow amine (POEA), benzethonium chloride (BZT), 5-bromo-5-nitro-1,3-dioxane, dimethyldioctadecylammonium chloride, and dioctadecyldimethylammonium bromide.
6. The composition of claim 4 , wherein the anionic surfactant is selected from the group of alkyl sulfates, alkyl ether sulfates, sulfonates, sulfonate fluorosurfactants, alkyl benzene sulfonates, phosphates, carboxylates, fatty acid salts, and carboxylate fluoro surfactants.
7. The composition of claim 4 , wherein an amount by weight ratio of ionic surfactants to a total amount by weight of the carbon nanotubes and the two or more graphene sheets have an average surface area in the range of 1:10 to 10:1.
8. The composition of claim 1 , wherein the carbon nanotubes are single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, or any combination thereof.
9. The composition of claim 1 , wherein the composition has a capacitance of at least about 75 F/g.
10. The composition of claim 1 , wherein the composition is porous with an average pore diameter of less than or equal to about 6 nm.
11. The composition of claim 1 , wherein the carbon nanotubes are overlapping, intertwined, or forming ropes and disposed between the two or more graphene sheets.
12. The composition of claim 1 , wherein the size of the two or more graphene sheets have an average surface area in the range of 100 nm 2 to 1000 nm 2 .
13. The composition of claim 1 , wherein the substituted ammonium ion is selected from the group of a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, or a quaternary ammonium ion.
14. The composition of claim 1 , wherein the substituted ammonium ion is represented by formula (1):
where R 1 , R 2 , R 3 , and R 4 are each independently hydrogen, C 1 -C 12 hydrocarbon, or an C 5 -C 10 aryl carbons, and wherein R 1 and R 2 are taken together to form a nitrogen-containing heterocycle.
15. The composition of claim 1 , wherein the substituted ammonium ion further comprises of a protonated pyrrolidine or a polyamine having two or more cationic amino groups covalently bonded to a hydrocarbon.
16. The composition of claim 1 , wherein the substituted ammonium ion further comprises of protonated forms of piperazine, alkylene diamines, or NH 3 —(CH 2 ) n —NH 3 , wherein n is 1 to 12.
17. The composition of claim 16 , wherein the alkylene diamines are selected from the group of ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenetetramine.
18. The composition of claim 1 , wherein the composition is in a suspension, a liquid, a solid, or in a granular form.
19. The composition of claim 18 , wherein the granular composition has a particle size in the range of 100 μm to 1 mm.
20. The composition of claim 1 , wherein the total amount of the two or more graphene sheets in the composition is in the range of 1% to 90% by weight.
21. The composition of claim 1 , wherein the total amount of the carbon nanotubes in the composition is in the range of 1% to 90% by weight.
22. The composition of claim 1 further comprises of additional materials wherein the additional materials include polymers, plasticizers, organic solvents, binders, sulfur, and metal oxide nanoparticles.
23. The composition of claim 22 , wherein the amount of the additional material in the composition is in the range of 1% by weight to 25% by weight.
24. The composition of claim 1 , wherein the composition has a BET surface area in the range of 400 m 2 /g to 2500 m 2 /g.