Proton conductive carbon material for fuel cell applications

• US 20040109816A1
• Filed: 05/23/2003
• Published: 06/10/2004
• Est. Priority Date: 05/23/2002
• Status: Abandoned Application

• Current Assignee: HSBC Bank USA National Association (HSBC Holdings plc)
• Original Assignee: HSBC Bank USA National Association (HSBC Holdings plc)
• Inventors: Srinivas, Bollepalli, Dotson, Anderson O.
• Application Number:
  US10/445,273
• Publication Number:
  US 20040109816A1
• Time in Patent Office: Days
• US Class Current: 423/449.2
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/19 Oil-absorption capacity, e.g. DBP values
• CPC Class Codes: C09C 1/56 Treatment of carbon black ; Purification
• CPC Class Codes: C09D 11/324 containing carbon black
• CPC Class Codes: C09D 17/005 Carbon black
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/926 on carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The present invention provides methods for the incorporation of sulfonate functional groups onto the surface of particulate carbonaceous materials and provides several surface-modified carbonaceous material compositions resulting therefrom. The composition can further comprise a conducting polymer. 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 sulfonating particulate carbonaceous material. The method can further comprise metallizing the sulfonated carbonaceous material.

Claims

1. A device comprising

a sulfonated particulate carbonaceous material.

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

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

4. The device of claim 1 wherein the sulfonated carbonaceous material comprises a plurality of sulfonate substituents of the general formula —

SO₃M surface-bonded thereto, wherein M is hydrogen or a cationic species, and wherein the surface atomic concentration of sulfur present within the surface bonded SO₃M moieties, measured by XPS, is greater than or equal to approximately 0.25% relative to the total surface atomic concentration of the carbonaceous material.

5. The device of claim 4 wherein the surface atomic concentration of the sulfur is in the range of from about 0.25% to about 5.0%.

6. The device of claim 4 wherein the surface atomic concentration of the sulfur is in the range of from about 0.35% to about 5.0%.

7. The device of claim 4 wherein M is a cationic species of sodium, potassium, lithium, or ammonium.

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

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

10. The device of claim 1 further comprising a conducting polymer.

11. The device of claim 10 wherein the conducting polymer contains hetero atoms.

12. The device of claim 10 wherein the conducting polymer is polyaniline, polypyrrole, polyfuran, polythiophene, or mixtures thereof.

13. The device of claim 10 wherein the conducting polymer is polyaniline, polypyrrole, polyfuran, polythiophene, poly(p-phenylene-oxide), poly(p-phenylene-sulfide), substituted conducting polymers, or mixtures thereof.

14. The device of claim 11 wherein the hetero atoms are N, O, and S.

15. The device of claim 11 wherein the hetero atoms are about 0.2 to about 15% of the composition according to XPS data.

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

17. The device of claim 10 wherein the conducting polymer is about 2% to about 50% of the composition.

18. The device of claim 10 wherein the conducting polymer is about 20% to about 50% of the composition.

19. The device of claim 10 wherein the polymer is grafted to the particulate sulfonated carbonaceous material.

20. The device of claim 10 wherein the polymer coats the sulfonated carbonaceous material.

21. The device of claim 1 further comprising a metal.

22. The device of claim 21 wherein the metal is platinum.

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

24. The device of claim 21 wherein about 2% to about 60% of the composition is the metal.

25. The device of claim 21 wherein about 20% to about 40% of the composition is the metal.

26. The device of claim 21 wherein the metal is uniformly distributed on the surface of the material.

30. The device of claim 1 further comprising an electrolyte membrane.

31. The device of claim 30 wherein the electrolyte membrane is Nafion®

.

34. The device of claim 1 wherein the device is a fuel cell, battery, or a capacitor.

27. A method for preparing a particulate carbonaceous material with enhanced electronic and protonic conductivity comprising

sulfonating a particulate carbonaceous material.

28. The method of claim 27 wherein the carbonaceous material is carbon black, graphite, nanocarbons, fullerenes, fullerenic material, finely divided carbon, or mixtures thereof.

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

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

33. The fuel cell of claim 32 wherein the PEM comprises a sulfonated particulate carbonaceous material.

35. A method of making a fuel cell comprising

a) producing a sulfonated particulate carbonaceous material by a method comprising

i) contacting an anhydride of the generic formula (R—

CO)₂O with sulfuric acid under conditions effective to produce an organic sulfite intermediate of the generic formula R—

(CO)O—

SO₃H, wherein R is an aliphatic substituent;

ii) contacting a carbonaceous material with the organic sulfite intermediate produced in a) under conditions effective to produce a surface-modified carbonaceous material comprising a plurality of sulfonate substituents of the general formula —

SO₃H surface-bonded thereto; and

iii) treating the surface-modified carbonaceous material produced in b) with a neutralizing agent under conditions effective to produce a surface-modified carbonaceous material comprising a plurality of sulfonate substituents of the general formula —

SO₃M surface-bonded thereto, wherein M is sodium, potassium, lithium, or ammonium;

(b) platinizing the sulfonated particulate carbonaceous material;

(c) making at least one electrode comprising the platinized sulfonated particulate carbonaceous material; and

(d) making a fuel cell comprising the at least one electrode.