High-density 3D graphene-based monolith and related materials, methods, and devices
A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm 3 . Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.
1. A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of restacked graphene sheets directly crosslinked by covalent carbon bonds, wherein the monolith has an electrical conductivity of at least 500 S/cm and a density of at least 0.2 g/cm 3 , wherein less than 10% of the graphene sheets are interconnected only by van der Waals force, and wherein the monolith has a Young's modulus of at least 5 GPa.
2. The composition of claim 1 , wherein the surfaces of the graphene sheets are free of carbon nanoparticles.
3. The composition of claim 1 , wherein in the monolith at least 70% of the covalent carbon bonds between the graphene sheets are sp 2 bonds.
4. The composition of claim 1 , wherein the monolith has a density of at least 0.5 g/cm 3 .
5. The composition of claim 1 , wherein the monolith has an electrical conductivity of at least 1000 S/cm.
6. The composition of claim 1 , wherein the monolith has a failure stress of at least 0.5 GPa.
7. The composition of claim 1 , wherein the monolith has a compressive strength of at least 100 MPa.
8. The composition of claim 1 , wherein the monolith has (i) a density of at least 0.5 g/cm 3 , (ii) an electrical conductivity of at least 1000 S/cm, and (iii) a Young's modulus of at least 5 GPa.
9. A device comprising the composition of claim 1 .
10. The device according to claim 9 , wherein the monolith wherein monolith is incorporated into an electrode.
11. The device according to claim 9 , wherein the monolith has (i) a density of at least 0.5 g/cm 3 , (ii) an electrical conductivity of at least 1000 S/cm, and (iii) a Young's modulus of at least 5 GPa.
12. The device according to claim 9 , wherein the device is a capacitor, a battery, an electrode, a sensor, an actuator, a membrane, a catalyst support, or a hydrogen storage device.
13. A method for obtaining the composition of claim 1 , comprising:
preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension is a graphene oxide (GO) suspension;
curing the reaction mixture to produce a wet gel;
drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freezing drying; and
pyrolyzing the dry gel to produce the composition comprising a high-density graphene-based monolith.
14. The method of claim 13 , wherein the suspension is a GO suspension comprising water or at least one organic solvent.
15. The method of claim 13 , wherein the suspension is a GO suspension comprising water or at least one organic solvent, and wherein the catalyst comprises ammonium hydroxide.
16. The method of claim 13 , wherein the reaction mixture is cured at a temperature of 100° C. or less.
17. The method of claim 13 , wherein the step of drying the wet gel comprises solvent exchange.
18. The method of claim 13 , wherein the step of drying the wet gel comprises washing the wet gel with deionized water and subsequently with acetone.
19. The method of claim 13 , wherein the step of drying the wet gel comprises drying the wet gel under ambient condition.
20. The method of claim 13 , wherein the step of pyrolyzing the dry gel comprises annealing the dry gel in an inert atmosphere at a temperature of 500° C. or higher.
21. The method of claim 13 , further comprising incorporating the high-density graphene-based monolith into an electrode.