Sulfonated conducting polymer-grafted carbon material for fuel cell applications

• US 7,413,683 B2
• Filed: 05/23/2003
• Issued: 08/19/2008
• Est. Priority Date: 05/23/2002
• Status: Expired due to Fees

• Current Assignee: HSBC Bank USA National Association (HSBC Holdings plc)
• Original Assignee: Columbian Chemicals Company (Aditya Birla Management Corp Pvt Ltd.)
• Inventors: Bollepalli, Srinivas
• Primary Examiner(s): Kopec; Mark
• Assistant Examiner(s): THOMAS, JAISON P
• Application Number:
  US10/445,074
• Publication Number:
  US 20040110051A1
• Time in Patent Office: 1,915 Days
• Field of Search: 977/737, 977/745, 252/500, 252/511, 252/512, 252/514
• US Class Current: 252/500
• 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 particulate composition comprising

a particulate carbonaceous material,

a sulfonated conducting polymer containing a hetero atom, and a metal,

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

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

3. The composition of claim 1, wherein the carbonaceous material comprises graphite, nanocarbon, fullerene, fullerenic material, finely divided carbon, or a mixture 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 comprises polyaniline, polypyrrole, polyfuran, polythiophene, or a mixture thereof.

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

8. The composition of claim 1, wherein the hetero atom is N, O, or S.

9. The composition of claim 1, wherein the hetero atom is 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, wherein the metal comprises platinum.

20. The composition of claim 1, wherein about 2% to about 80% of the composition is the metal.

21. The composition of claim 1, wherein about 2% to about 60% of the composition is the metal.

22. The composition of claim 1, wherein about 20% to about 40% of the composition is the metal.

23. The composition of claim 1, wherein the metal is uniformly distributed on the surface of the composition.

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

oxidatively polymerizing monomer of a conducting polymer containing a hetero atom 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;

and then metallizing the sulfonated conducting polymer-grafted carbonaceous material.

25. The method of claim 24, wherein the carbonaceous material comprises graphite, nanocarbon, fullerene, fullerinic material, finely divided carbon, or a mixture thereof.

26. The method of claim 24, wherein the carbonaceous material comprises carbon black.

27. The method of claim 24, wherein the monomer of a conducting polymer comprises an amino aryl or a nitrogen heterocycle.

28. The method of claim 24, wherein the oxidative polymerization is in the presence of an oxidizing agent.

29. The method of claim 24, wherein the oxidatively polymerizing comprises adding an oxidizing agent to a mixture of the carbonaceous material and a monomer of the conducting polymer.

30. The method of claim 29, wherein the mixture of the carbonaceous material and the monomer of the conducting polymer further comprises an acid solvent whereby the mixture is a slightly acidic environment.

31. The method of claim 30, wherein the slightly acidic environment is a pH of less than 7.

32. The method of claim 30, wherein the slightly acidic environment is a pH of about 3 to about 4.

33. The method of claim 29, wherein the oxidizing agent comprises ammonium persulfate, sodium persulfate, ferric chloride, aluminum chloride, hydrogen peroxide, potassium permanganate, sodium permanganate, potassium chlorate, or a combination of oxidizing agents thereof.

34. The method of claim 24, wherein the conducting polymer comprises polyaniline, polypyrrole, polyfuran, polythiophene, poly(p-phenylene-oxide), poly(p-phenylene-sulfide), a substituted conducting polymer thereof, or a mixture thereof.

35. The method of claim 24, wherein the polymer is directly sulfonated after oxidatively polymerizing the monomer with the carbonaceous material.

36. The method of claim 24, wherein the monomer is a sulfonated monomer of the conducting polymer.

37. The method claim 35, wherein the direct sulfonation is by addition of a sulfonating agent.

38. The method claim 37, wherein the sulfonating agent is chlorosulfonic acid.

39. The method claim 37, wherein the sulfonating agent is acetylsulfonic acid.

40. The method of claim 24, wherein the metallizing comprises adding a metal-containing material to the conducting polymer-grafted carbonaceous material.

41. The method of claim 40, wherein the metallizing further comprises adding a reducing agent.

42. The method of claim 24, wherein the metallizing is plantinizing.

43. The method of claim 41, wherein the reducing agent comprises formaldehyde, sodium borohydride, hydrogen, hydrazine, hydroxyl amine, or a mixture of reducing agents thereof.

44. The method of claim 40, wherein the metal-containing material comprises chloroplatinic acid, platinum nitrate, platinum halide, platinum cyanide, platinum sulfide, organoplatinum salt, or a mixture thereof.

45. A composition made by the method comprising

oxidatively polymerizing monomer of a conducting polymer containing a hetero atom 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;

then metallizing the sulfonated conducting polymer-grafted carbonaceous material.