Sulfonated conducting polymer-grafted carbon material for fuel cell applications

• US 20040169165A1
• Filed: 02/25/2004
• Published: 09/02/2004
• Est. Priority Date: 05/23/2002
• Status: Active Grant

• Current Assignee: HSBC Bank USA National Association (HSBC Holdings plc)
• Original Assignee: HSBC Bank USA National Association (HSBC Holdings plc)
• Inventors: Srinivas, Bollepalli
• Granted Patent: US 7,390,441 B2
• Time in Patent Office: Days
• US Class Current: 252/511
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 4/926 on carbon or graphite
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1025 having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters
• CPC Class Codes: H01M 8/103 having nitrogen, e.g. sulfonated polybenzimidazoles [S-PBI], polybenzimidazoles with phosphoric acid, sulfonated polyamides [S-PA] or sulfonated polyphosphazenes [S-PPh]
• CPC Class Codes: H01M 8/1032 having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A composition comprising particulate carbonaceous material and a sulfonated conducting polymer containing hetero atoms. The composition can further comprise a metal. Devices comprising the composition can be constructed including supported electrocatalysts, membrane electrode assemblies, and fuel cells. A method for preparing the composition comprises oxidatively polymerizing with ozone a monomer of a conducting polymer containing hetero atoms in the presence of a carbonaceous material and sulfonating the polymer or the monomer. The method grafts the sulfonated conducting polymer to the carbonaceous material. The method can further comprise metallizing the polymer-grafted carbonaceous material.

Claims

1. A method for preparing a carbon composition with enhanced electronic and protonic conductivity comprising

oxidatively polymerizing with an oxidizing agent comprising ozone a monomer of a conducting polymer containing hetero atoms with particulate carbonaceous material to form a conducting polymer-grafted carbonaceous material, wherein either the monomer is sulfonated or the polymer is subsequently sulfonated, to thereby produce a sulfonated conducting polymer-grafted carbonaceous material.

2. The method of claim 1, wherein the carbonaceous material is carbon black, graphite, nanocarbons, fullerenes, fullerinic material, finely divided carbon, or mixtures thereof.

3. The method of claim 1, wherein the carbonaceous material is carbon black.

4. The method of claim 1, wherein the monomer of a conducting polymer is an amino aryl or a nitrogen heterocycle.

5. The method of claim 1, wherein the oxidatively polymerizing comprises adding ozone to a mixture of the carbonaceous material and the monomer of the conducting polymer.

6. The method of claim 5, wherein the mixture of the carbonaceous material and the monomer of the conducting polymer further comprises an acid solvent to form a slightly acidic environment.

7. The method of claim 6, wherein the slightly acidic environment is a pH of about less than 7.

8. The method of claim 6, wherein the slightly acidic environment is a pH of about 3 to about 4.

9. The method of claim 1, wherein the conducting polymer is polyaniline, polypyrrole, polyfuran, polythiophene, poly(p-phenylene-oxide), poly(p-phenylene-sulfide), substituted conducting polymers, or a mixture thereof.

10. The method of claim 1, wherein the polymer is directly sulfonated after oxidatively polymerizing the monomer with the carbonaceous material.

11. The method of claim 1, wherein the monomer is a sulfonated monomer of the conducting polymer.

12. The method claim 10, wherein the direct sulfonation is by addition of a sulfonating agent.

13. The method claim 12, wherein the sulfonating agent is chlorosulfonic acid.

14. The method claim 12, wherein the sulfonating agent is acetylsulfonic acid.

15. The method of claim 1, further comprising metallizing the conducting polymer-grafted carbonaceous material.

16. The method of claim 15, wherein the metallizing comprises adding a metal-containing material to the conducting polymer-grafted carbonaceous material.

17. The method of claim 16, wherein the metallizing further comprises adding a reducing agent.

18. The method of claim 15, wherein the metallizing is plantinizing.

19. The method of claim 17, wherein the reducing agent is formaldehyde, sodium borohydride, hydrogen, hydrazine, hydroxylamine, or a mixture of reducing agents.

20. The method of claim 16, wherein the metal-containing material is chloroplatinic acid, platinum nitrate, platinum halides, platinum cyanide, platinum sulfide, organoplatinum salts, or a mixture thereof.

21. A composition made by the method of claim 1.