Simple route to highly conductive porous graphene from carbon nanodots for supercapacitor applications

Patent metadata

Field	Value
Publication number	US-12283424-B2
Application number	US-202117401804-A
Country	US
Kind code	B2
Filing date	Aug 13, 2021
Priority date	Jul 14, 2017
Publication date	Apr 22, 2025
Grant date	Apr 22, 2025

Abstract

Disclosed herein are methods and compositions directed to a promising class of nanomaterials called organic nanoparticles, or carbon nanodots. The present disclosure provides a facile method for the conversion of biomolecule-based carbon nanodots into high surface area three-dimensional graphene networks with excellent electrochemical properties.

First claim

What is claimed is:

1. A method for synthesizing a carbon network comprising:
a. dissolving carbon nanodots (CNDs) in a solvent to form a CND slurry;
b. casting the CND slurry onto a substrate;
c. drying the CND slurry on the substrate to form a CND film; and
d. irradiating the CND film with a light beam to convert at least a portion of the CND film into the carbon network comprising turbostratic graphene.

2. The method of claim 1 , wherein irradiating the CND film with the light beam is performed at a predetermined temperature in an oxygen-free environment for a predetermined time.

3. The method of claim 2 , wherein the predetermined temperature is about 200° C. to about 400° C.

4. The method of claim 2 , wherein the predetermined time is about 1 hour to about 3 hours.

5. The method of claim 1 , wherein the solvent is an organic liquid.

6. The method of claim 5 , wherein the organic liquid is N-methyl-2-pyrrolidone (NMP).

7. The method of claim 6 , wherein the CND slurry has a CND-to-NMP ratio of about 0.3:1 to about 0.9:1.

8. The method of claim 1 , wherein the light beam is generated by a laser.

9. The method of claim 8 , wherein the laser is a carbon dioxide laser or an infrared laser.

10. The method of claim 1 , wherein the power level of the light beam is between about 8 watts (W) and about 13 W.

11. The method of claim 1 , further comprising synthesizing the CNDs by microwave-assisted thermolysis and annealing.

12. The method of claim 11 , wherein the thermolysis is performed with a small molecule comprising citric acid and urea.

13. The method of claim 11 , wherein annealing is performed:
a. at temperatures up to about 400° C.;
b. in an oxygen-free environment;
c. under a constant argon flow; or
d. any combination thereof.

14. The method of claim 1 , wherein irradiating the CND film removes about 60% of the CND film.

15. The method of claim 1 , wherein the carbon network is porous.

16. The method of claim 15 , wherein the carbon network has an average pore size of about 10 nanometers (nm) to about 100,000 nm.

17. The method of claim 1 , wherein the carbon network has an elemental composition of at least about 40% carbon.

18. The method of claim 17 , wherein the carbon network has an elemental composition of about 89% carbon, about 8% oxygen, and nitrogen.

19. The method of claim 1 , wherein the turbostratic graphene has a particle size of about 2 nm to about 50 nm.

20. The method of claim 1 , wherein the turbostratic graphene has an active surface area of at least about 230 square meters per gram.

Assignees

• Univ California

Inventors

• Strauss Volker
• Kaner Richard B
• El-Kady Maher F

Classifications

• H01G11/32

  Carbon-based · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C01B2204/22

  Electronic properties · CPC title

• C01B2204/32

  Size or surface area · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title