System and method for forming activated carbon aerogels and performing 3d printing

Patent metadata

Field	Value
Publication number	US-2018345598-A1
Application number	US-201715613630-A
Country	US
Kind code	A1
Filing date	Jun 5, 2017
Priority date	Jun 5, 2017
Publication date	Dec 6, 2018
Grant date	—

Abstract

Making a carbon aerogel involves 3-D printing an ink to make a printed part, removing the solvent from the printed part, and carbonizing the printed part (with the solvent removed) to make the aerogel. The ink is based on a solution of a resorcinol-formaldehyde resin (RF resin), water, and an organic thickener. Advantageously, the RF resin contains an acid catalyst, which tends to produce carbon aerogels with higher surface areas upon activation than those produced from methods involving an ink composition containing a base catalyzed resin.

First claim

What is claimed is:

1 . A method of forming a carbon aerogel, comprising
3-D printing an ink to make a printed part, wherein the ink comprises solvent, a resorcinol-formaldehyde resin, and an organic thickener; removing the solvent from the printed part; and carbonizing the printed part to make the aerogel, wherein the resorcinol-formaldehyde resin comprises an acid catalyst and has a formaldehyde: resorcinol molar ratio greater than 1:1, wherein the thickener is soluble in water, is made of only C, H, and O atoms, and contains only ether or alcohol functional groups.

2 . The method of claim 1 , wherein the ink further comprises a thixotropic agent.

3 . The method of claim 2 , wherein the thixotropic agent comprises fumed silica and the method further comprises HF etching to remove silica from the printed part.

4 . The method of claim 1 , wherein the organic thickener comprises a soluble cellulose derivative or a soluble polyoxyalkylene compound.

5 . The method of claim 1 , wherein the acid catalyst comprises acetic acid.

6 . The method of claim 1 , wherein the ink further comprises graphene oxide.

7 . The method of claim 1 , wherein the ink is free of graphene oxide.

8 . A carbon aerogel made by the method of claim 1 .

9 . A 3-D printing ink, comprising:
a solvent comprising water; an organic thickener; resorcinol and formaldehyde; and an acid catalyst that catalyzes a reaction between the resorcinol and formaldehyde, wherein the thickener is soluble in water, is made of only C, H, and O atoms, and contains only ether or alcohol functional groups.

10 . The ink of claim 9 , further comprising a thixotropic additive.

11 . The ink of claim 10 , wherein the thixotropic additive comprises fumed silica.

12 . The ink of claim 9 , wherein the acid catalyst comprises acetic acid.

13 . The ink of claim 9 , wherein the molar ratio of resorcinol to formaldehyde is less than 1:1.

14 . The ink of claim 9 , further comprising graphene oxide.

15 . The ink of claim 9 , wherein the thickener comprises hydroxypropylmethylcellulose.

16 . The ink of claim 9 , wherein the thickener comprises a polyoxyalkylene compound.

17 . The ink of claim 9 , comprising 10% to 60% by weight of the resin.

18 . A supercapacitor comprising a positive electrode, a negative electrode, and a separator disposed between the electrodes, wherein at least one of the positive electrode, negative electrode, and separator comprises a carbon aerogel according to claim 7 .

19 . The supercapacitor of claim 18 , characterized by a specific capacitance greater than 240 F/g.

Assignees

• L Livermore Nat Security Llc

Inventors

• Chandrasekaran Swetha
• Baumann Theodore F
• Worsley Marcus A

Classifications

• C09D11/103 Primary

  of aldehydes, e.g. phenol-formaldehyde resins · CPC title

• C01B32/05

  Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30 · CPC title

• B29C64/106

  using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material · CPC title

• H01G11/52

  Separators · CPC title

• H01G11/32

  Carbon-based · CPC title