Sulfonated conducting polymer-grafted carbon material for fuel cell applications

• US 20040110051A1
• Filed: 05/23/2003
• Published: 06/10/2004
• 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 7,413,683 B2
• Time in Patent Office: Days
• US Class Current: 429/33
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/881 Electrolytic membranes
• CPC Class Codes: H01M 4/8828 Coating with slurry or ink
• CPC Class Codes: H01M 4/8882 Heat treatment, e.g. drying, baking
• 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 4/96 Carbon-based electrodes
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1009 with one of the reactants being liquid, solid or liquid-charged H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1018 Polymeric electrolyte materials
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• 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 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 composition comprising

a particulate carbonaceous material, and

a sulfonated conducting polymer containing hetero atoms

wherein the sulfonated conducting polymer is grafted onto the carbonaceous material.

2. The composition of claim 1 wherein the carbonaceous material is carbon black.

3. The composition of claim 1 wherein the carbonaceous material is carbon black, graphite, nanocarbons, fullerenes, fullerenic material, finely divided carbon, or mixtures thereof.

4. The composition of claim 1 wherein the carbonaceous material is less than about 98% of the composition.

5. The composition of claim 1 wherein the carbonaceous material is about 50% to about 80% of the composition.

6. The composition of claim 1 wherein the conducting polymer is polyaniline, polypyrrole, polyfuran, polythiophene, or mixtures thereof.

7. The composition of claim 1 wherein the conducting polymer is polyaniline, polypyrrole, polyfuran, polythiophene, poly(p-phenylene-oxide), poly(p-phenylene-sulfide), substituted conducting polymers, or mixtures thereof.

8. The composition of claim 1 wherein the hetero atoms are N, O, and S.

9. The composition of claim 1 wherein the hetero atoms are about 0.2-15% of the composition according to XPS data.

10. The composition of claim 1 wherein the sulfonated conducting polymer is greater than about 0% and less than about 100% of the composition.

11. The composition of claim 1 wherein the conducting polymer is about 2% to about 50% of the composition.

12. The composition of claim 1 wherein the sulfonated conducting polymer is about 20% to about 50% of the composition.

13. The composition of claim 1 wherein the polymer comprises about 0.1 to about 3 equivalent sulfonate groups per monomer unit.

14. The composition of claim 13 wherein the polymer comprises about 0.4 equivalent sulfonate groups per monomer unit.

15. The composition of claim 13 wherein the polymer comprises about 1 equivalent sulfonate groups per monomer unit.

16. The composition of claim 13 wherein the polymer comprises about 2 equivalent sulfonate groups per monomer unit.

17. The composition of claim 1 wherein the sulfonated polymer is concurrently formed and grafted by oxidatively polymerizing a monomer of the conducting polymer in the presence of the carbonaceous material followed by direct sulfonation of the resulting polymer-carbonacaceous material.

18. The composition of claim 1 wherein the sulfonated polymer is concurrently formed and grafted by oxidatively polymerizing a sulfonated monomer of the conducting polymer in the presence of the carbonaceous material.

19. The composition of claim 1 further comprising a metal.

20. The composition of claim 19 wherein the metal is platinum.

21. The composition of claim 19 wherein about 2% to about 80% of the composition is the metal.

22. The composition of claim 19 wherein about 2% to about 60% of the composition is the metal.

23. The composition of claim 19 wherein about 20% to about 40% of the composition is the metal.

24. The composition of claim 19 wherein the metal is uniformly distributed on the surface of the composition.

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

oxidatively polymerizing 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.

26. The method of claim 25 wherein the carbonaceous material is carbon black, graphite, nanocarbons, fullerenes, fullerinic material, finely divided carbon, or mixtures thereof.

27. The method of claim 25 wherein the carbonaceous material is carbon black.

28. The method of claim 25 wherein the monomer of a conducting polymer is an amino aryl or a nitrogen heterocycle.

29. The method of claim 25 wherein the oxidative polymerization is in the presence of an oxidizing agent.

30. The method of claim 25 wherein the oxidatively polymerizing comprises adding an oxidizing agent to a mixture of the carbonaceous material and a monomer of the conducting polymer.

31. The method of claim 30 wherein the mixture of the carbonaceous material and the monomer of the conducting polymer wherein the mixture is a slightly acidic environment further comprises an acid solvent.

32. The method of claim 31 wherein the slightly acidic environment is a pH of about less than 7.

33. The method of claim 31 wherein the slightly acidic environment is a pH of about 3 to about 4.

34. The method of claim 30 wherein the oxidizing agent is ammonium persulfate, sodium persulfate, ferric chloride, aluminum chloride, hydrogen peroxide, potassium permanganate, sodium permanganate, potassium chlorate, or a combination of oxidizing agents.

35. The method of claim 25 wherein the conducting polymer is polyaniline, polypyrrole, polyfuran, polythiophene, poly(p-phenylene-oxide), poly(p-phenylene-sulfide), substituted conducting polymers, or mixtures thereof.

36. The method of claim 25 wherein the polymer is directly sulfonated after oxidatively polymerizing the monomer with the carbonaceous material.

37. The method of claim 25 wherein the monomer is a sulfonated monomer of the conducting polymer.

38. The method claim 36 wherein the direct sulfonation is by addition of a sulfonating agent.

39. The method claim 38 wherein the sulfonating agent is chlorosulfonic acid.

40. The method claim 38 wherein the sulfonating agent is acetylsulfonic acid.

41. The method of claim 25 further comprising metallizing the conducting polymer-grafted carbonaceous material.

42. The method of claim 41 wherein the metallizing comprises adding a metal-containing material to the conducting polymer-grafted carbonaceous material.

43. The method of claim 42 wherein the metallizing further comprises adding a reducing agent.

44. The method of claim 41 wherein the metallizing is plantinizing.

45. The method of claim 43 wherein the reducing agent is formaldehyde, formic acid, sodium borohydride, hydrogen, hydrazine, hydroxyl amine, or a mixture of reducing agents.

46. The method of claim 42 wherein the metal-containing material is chloroplatinic acid, platinum nitrate, platinum halides, platinum cyanide, platinum sulfide, organoplatinum salts, or a mixture thereof.

47. A composition made by the method of claim 25.

48. A device comprising

a particulate carbonaceous material, and

sulfonated conducting polymer containing hetero atoms wherein the conducting polymer is grafted onto the carbonaceous material.

49. The device of claim 48 further comprising a metal.

50. The device of claim 49 wherein the metal is platinum.

51. The device of claim 49 wherein the metal is 2-80% of the device.

52. The device of claim 48 further comprising an electrolyte membrane.

53. The device of claim 52 wherein the electrolyte membrane is Nafion®

.

56. The device of claim 48 wherein the device is a fuel cell, battery, or a capacitor.

54. A fuel cell comprising an anode, a cathode, and a proton exchange membrane (PEM).

55. The fuel cell of claim 54 wherein the PEM comprises a particulate carbonaceous material, and

a sulfonated conducting polymer containing hetero atoms wherein the conducting polymer is grafted onto the carbonaceous material.