Metallization of Bacterial Cellulose for Electrical and Electronic Device Manufacture

• US 20110014525A1
• Filed: 09/23/2010
• Published: 01/20/2011
• Est. Priority Date: 12/14/2001
• Status: Active Grant

• Current Assignee: Barbara R. Evans, Hugh M O'Neill, Jonathan Woodward, Valerie Malyvanh Jansen
• Original Assignee: Barbara R. Evans, Hugh M O'Neill, Jonathan Woodward, Valerie Malyvanh Jansen
• Inventors: Evans, Barbara R., O'Neill, Hugh M., Woodward, Jonathan, Jansen, Valerie Malyvanh
• Granted Patent: US 7,955,759 B2
• Time in Patent Office: Days
• US Class Current: 429/401
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8817 Treatment of supports before application of the catalytic active composition coated porous composites H01M8/0245
• CPC Class Codes: H01M 4/8842 Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 4/96 Carbon-based electrodes
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• 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 the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

Claims

1. A method for forming a fuel cell, the method comprising:

providing an electrode support structure comprising bacterial cellulose;

placing the electrode support structure in a solution of a metal salt for a sufficient time period such that the metal salt is reduced to metallic form and the metal precipitates in or on the electrode support structure to form an electrode material;

providing an electrolyte membrane;

placing an anode on one side of the electrolyte membrane; and

placing a cathode on an opposite side of the electrolyte membrane,

wherein one of the anode and the cathode comprises the electrode material.

2. The method of claim 1 wherein:

the anode comprises the electrode material and the cathode comprises the electrode material.

3. The method of claim 1 wherein:

the electrode support structure comprises hydrated bacterial cellulose, and

the method further comprises dehydrating the electrode support structure after the metal precipitates in or on the electrode support structure to form the electrode material.

4. The method of claim 1 wherein:

the electrolyte membrane comprises bacterial cellulose.

5. The method of claim 1 wherein:

the electrolyte membrane comprises hydrated bacterial cellulose,

the electrode support structure comprises hydrated bacterial cellulose,

the anode comprises the electrode material,

the cathode comprises the electrode material, and

the method further comprises dehydrating the electrolyte membrane, the anode and the cathode after placing the anode on one side of the electrolyte membrane and placing the cathode on the opposite side of the electrolyte membrane thereby affixing the anode and the cathode to the electrolyte membrane.

6. The method of claim 1 wherein:

the electrolyte membrane comprises hydrated bacterial cellulose,

the electrode support structure comprises hydrated bacterial cellulose,

the method further comprises dehydrating the electrode support structure after the metal precipitates in or on the electrode support structure to form the electrode material,

the anode comprises the electrode material,

the cathode comprises the electrode material, and

the method further comprises dehydrating the electrolyte membrane after placing the anode on one side of the electrolyte membrane and placing the cathode on the opposite side of the electrolyte membrane thereby affixing the anode and the cathode to the electrolyte membrane.

7. The method of claim 1 wherein:

the metal salt is selected from coordination compounds including a platinum metal group complex ion, and mixtures thereof.

8. The method of claim 1 wherein the metal salt is a coordination compound including a palladium complex ion.

9. The method of claim 1 wherein the method further comprises contacting the electrode support structure with a reductant fluid when the electrode support structure is placed in the solution of the metal salt.

10. The method of claim 1 wherein the electrolyte membrane comprises bacterial cellulose and a sulfonated polymer.

11. A method for recovering the metal from the fuel cell produced by the method of claim 1, the method for recovering comprising burning or hydrolyzing the electrode material.

12. A method for forming an electrolyte membrane for a fuel cell, the method comprising:

providing a support structure comprising hydrated bacterial cellulose;

infusing the support structure with a metal salt and/or a sulfonated polymer; and

dehydrating the support structure to form the electrolyte membrane.

13. The method of claim 12 wherein:

the metal salt is selected from alkali metal salts.

14. The method of claim 12 wherein:

the support structure is infused with a metal salt and a sulfonated polymer.

15. The method of claim 12 wherein:

the support structure is infused with a metal salt.

16. The method of claim 12 wherein:

the support structure is infused with a sulfonated polymer.

17. An electrolyte membrane for a fuel cell, the electrolyte membrane comprising:

a support structure comprising bacterial cellulose; and

a metal salt disposed in or on the support structure.

18. The electrolyte membrane of claim 17 wherein:

the metal salt is selected from alkali metal salts.

19. The electrolyte membrane of claim 17 further comprising:

a sulfonated polymer disposed in or on the support structure.

20. The electrolyte membrane of claim 19 wherein:

the sulfonated polymer is carrageenan.