Ion exchange system structure with a microtextured surface, method of manufacture, and method of use thereof

• US 20030170519A1
• Filed: 03/07/2002
• Published: 09/11/2003
• Est. Priority Date: 03/07/2002
• Status: Active Grant

• Current Assignee: Intelligent Energy Limited (Lb-shell Plc)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Mittelstadt, Laurie S., Smith, Joshua W.
• Granted Patent: US 6,869,712 B2
• Time in Patent Office: Days
• US Class Current: 429/30
• CPC Class Codes: C08J 5/2218 Synthetic macromolecular compounds
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 4/0407 by coating on an electrolyte layer
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/881 Electrolytic membranes
• CPC Class Codes: H01M 4/8853 Electrodeposition
• CPC Class Codes: H01M 4/8867 Vapour deposition
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 8/0206 Metals or alloys
• CPC Class Codes: H01M 8/083 Alkaline fuel cells
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A method for roughening a surface of an ion exchange system structure using laser interaction with a surface. The laser surface roughening process allows the use of a wide range of substrates such as metals, ceramics, silicates, polymers and the like, including varieties which can not be fabricated in a fine fibrous structure. The surface roughened ion exchange system structure may be used as an ion-exchange media in applications such as fuel cells, batteries, and other catalysis systems where a high surface exchange area is desirable.

Claims

1. A substrate for an ion-exchange system structure, said substrate comprising a surface wherein at least a portion of the surface is irradiated by a laser radiation to enlarge a reactive surface area.

2. The substrate of claim 1, wherein the portion of the surface is irradiated by exposing the surface to the laser radiation near an ablation threshold of the membrane.

3. The substrate of claim 1, wherein the portion of the surface is irradiated by melting, boiling, or quenching part of the surface with laser radiation.

4. The substrate of claim 1, wherein the laser irradiated surface is coated with a layer of conductive material.

5. The substrate of claim 4, wherein the conductive material is a metal or an alloy.

6. The substrate of claim 4, wherein the layer of conductive material is further coated with a continuous or discontinuous layer of catalytic material.

7. The substrate of claim 6, wherein the catalytic material is selected from a group consisting of Pt, Pt alloys, V, V alloys, titanium dioxide, iron, nickel, lithium and gold.

8. The substrate of claim 1, wherein the laser irradiated surface is coated with a continuous or discontinuous layer of catalytic material.

9. The substrate of claim 8, wherein the catalytic material is selected from a group consisting of Pt, Pt alloys, V, V alloys, titanium dioxide, iron, nickel, lithium and gold.

10. The substrate of claim 8, further comprising micro openings wherein a fuel flows through the micro openings to reach the catalytic material.

11. An ion exchange membrane with an enlarged reactive surface, said membrane is produced by:

providing a laser roughened surface;

covering the laser roughened surface with a solution;

allowing the solution to solidify to form an ion exchange membrane; and

separating the ion exchange membrane from the laser roughened surface,

wherein said ion exchange membrane has an enlarged reactive surface that is a negative replica of the laser roughened surface.

12. The ion exchange membrane of claim 11, wherein the solution comprises an electrolyte and a solvent.

13. The ion exchange membrane of claim 12, wherein the electrolyte is selected from a group consisting of sulfonated ion-conducting aromatic polymer, phosphonated ion-conducting aromatic polymer, carboxylated ion-conducting aromatic polymer and perfluorinated co-polymer, and wherein the solvent is selected from a group consisting of lower aliphatic alcohols, water, and a mixture thereof.

14. The ion exchange membrane of claim 11, wherein the enlarged reactive surface is further coated with a layer of conductive material.

15. The ion exchange membrane of claim 14, wherein the conductive material is a metal or an alloy.

16. The ion exchange membrane of claim 14, wherein the enlarged reactive surface is further coated with a continuous or discontinuous layer of catalytic material.

17. The ion exchange membrane of claim 16, wherein the catalytic material is selected from a group consisting of Pt, Pt alloys, V, V alloys, titanium dioxide, iron, nickel, lithium and gold.

18. An ion exchange membrane with an enlarged reactive surface, said ion exchange membrane is produced by:

providing an ion exchange membrane;

providing a laser roughened surface;

stamping the ion exchange membrane with the laser roughened surface; and

separating the ion exchange membrane from the laser roughened surface,

wherein the stamped ion exchange membrane has an enlarged reactive surface that is a negative replica of the laser roughened surface.

19. An ion exchange membrane with enlarged reactive surfaces on a front side and a back side, said ion exchange membrane is produced by:

providing a mold having an inner upper surface and an inner lower surface;

filling the mold with a solution;

allowing the solution to solidify to form an ion exchange membrane; and

separating the ion exchange membrane from the mold,

wherein the inner upper surface and inner lower surface of the mold are roughened by laser irradiation, and wherein said ion exchange membrane has an upper surface that is a negative replica of the inner upper surface of the mold and a lower surface that is a negative replica of the inner lower surface of the mold.

20. A fuel cell assembly comprising:

an anode;

a cathode;

an electrolyte connecting the anode and the cathode; and

a fuel,

wherein said anode comprises an ion exchange surface enlarged by laser radiation.

21. The fuel cell assembly of claim 20, wherein the ion exchange surface is coated by a layer of conductive material and a layer of catalytic material.

22. The fuel cell assembly of claim 21, wherein the layer of catalytic material is a discontinuous layer.

23. The fuel cell assembly of claim 21, wherein the conductive material is a metal or an alloy, and wherein the catalytic material is selected from a group consisting of Pt and Pt alloys.

24. The fuel cell assembly of claim 20, wherein the electrolyte is a liquid electrolyte.

25. The fuel cell assembly of claim 21, wherein the electrolyte is a PEM, and wherein said anode contains micro openings so that the fuel can flow through the micro openings to reach the catalytic material on the ion exchange surface.

26. The fuel cell assembly of claim 20, wherein said cathode comprises an ion exchange surface enlarged by laser radiation.

27. A fuel cell assembly comprising:

a fuel; and

a PEM-electrode structure comprising a PEM,

wherein said PEM is produced by one of;

(a) solidifying a solution on a laser roughened surface;

(b) solidifying a solution in a mold with a laser roughened inner surface;

or

(c) stamping an ion-exchange membrane with a laser roughened surface.

28. The fuel cell assembly of claim 27, wherein the PEM-electrode structure further comprise a layer of conductive material and a layer of catalytic material.

29. The fuel cell assembly of claim 28, wherein the conductive material is a metal or an alloy, and wherein the catalytic material is selected from a group consisting of Pt and Pt alloys.

30. A method for producing an ion exchange membrane with a roughened surface, comprising:

providing a laser roughened surface;

covering the laser roughened surface with a solution;

allowing the solution to solidify to form an ion exchange membrane; and

separating the ion exchange membrane from the laser roughened surface, said ion exchange membrane having a roughened surface that is a negative replica of the laser roughened surface.

31. The method of claim 30, wherein the solution comprises a electrolyte material and a solvent.

32. The method of claim 31, wherein the electrolyte is selected from a group consisting of sulfonated ion-conducting aromatic polymer, phosphonated ion-conducting aromatic polymer, carboxylated ion-conducting aromatic polymer andperfluorinated co-polymer, and wherein the solvent is selected from a group consisting of lower aliphatic alcohols, water, and a mixture thereof.

33. A method for producing a ion exchange membrane with a roughened surface, comprising:

providing a mold having an inner upper surface and an inner lower surface;

filling the mold with a solution;

allowing the solution to solidify to form an ion exchange membrane; and

separating the ion exchange membrane from the mold,

wherein the inner upper surface and inner lower surface of the mold are roughened by laser irradiation, and wherein said ion exchange membrane has an upper surface that is a negative replica of the inner upper surface of the mold and a lower surface that is a negative replica of the inner lower surface of the mold.

34. The method of claim 33, wherein the solution comprises a electrolyte material and a solvent.

35. The method of claim 34, wherein the electrolyte is selected from a group consisting of sulfonated ion-conducting aromatic polymer, phosphonated ion-conducting aromatic polymer, carboxylated ion-conducting aromatic polymer andperfluorinated copolymer, and wherein the solvent is selected from a group consisting of lower aliphatic alcohols, water, and a mixture thereof.

36. A method for producing a ion exchange membrane with a roughened surface, comprising:

providing an ion exchange membrane;

providing a laser roughened surface;

stamping the ion exchange membrane with the laser roughened surface; and

separating the ion exchange membrane from the laser roughened surface,

wherein the stamped ion exchange membrane has a roughened surface that is a negative replica of the laser roughened surface.

37. A method for roughening a surface of an ion exchange system structure with laser radiation, comprising:

providing an ion exchange system structure;

providing a source of laser radiation; and

irradiating a surface of the ion exchange system structure with laser radiation to create a roughened surface that increases reactive exchange area of said surface.

38. The method of claim 37, further comprising:

depositing a laser shading material on the surface of the ion exchange system structure, near the surface of the ion exchange system structure, or in the volume of the ion exchange system structure before laser radiation.

39. The method of claim 37, wherein the source of laser radiation is a pulse laser.

40. The method of claim 39, wherein in the pulse laser is a NeYAG laser or an excimer laser.

41. The method of claim 37, wherein the laser radiation is provided through a mask to generate shaded areas on the surface of the ion exchange system structure.

42. The method of claim 37, wherein the laser radiation produces a diffracted image.

43. The method of claim 37, wherein the ion exchange system structure is made of polymers, ceramics, or silicates.

44. The method of claim 37, wherein the surface of ion exchange system structure is irradiated with laser radiation near an ablation threshold of a material being irradiated.

45. The method of claim 37, wherein the surface of the ion exchange system structure is irradiated with laser radiation to melt, boil and quench part of the surface.

46. A method for roughening a surface of an ion exchange system structure with laser radiation, comprising:

providing an ion exchange system structure;

providing a source of laser radiation; and

irradiating a surface of the ion exchange system structure with laser radiation to create a roughened surface that increases a reactive surface area of said surface,

wherein the ion exchange system structure is made of a polymer or a silicate, the source of laser radiation is a pulse excimer laser or a NeYAG laser, and the roughened surface is created either by irradiating the surface of the ion exchange system structure with laser radiation near an ablation threshold of a surface material, or by irradiating the surface of the ion exchange system structure with laser radiation to melt, boil and quench part of the surface.