Fuel cells incorporating magnetic composites having distinct flux properties

• US 5,928,804 A
• Filed: 03/24/1998
• Issued: 07/27/1999
• Est. Priority Date: 08/25/1994
• Status: Expired due to Term

• Current Assignee: University of Iowa Research Foundation
• Original Assignee: University of Iowa Research Foundation
• Inventors: Tinoco, Flavio, Leddy, Johna, Amarasinghe, Sudath
• Primary Examiner(s): KALAFUT, STEPHEN J
• Application Number:
  US09/046,628
• Time in Patent Office: 490 Days
• Field of Search: 429/10, 429/40, 429/42
• US Class Current: 429/10
• CPC Class Codes: B03C 1/01 by addition of magnetic adjuvants
• CPC Class Codes: B03C 1/025 High gradient magnetic separators
• CPC Class Codes: B03C 1/034 characterised by the matrix elements
• CPC Class Codes: B03C 1/035 Open gradient magnetic separators, i.e. separators in which the gap is unobstructed, characterised by the configuration of the gap
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C23C 24/08 by application of heat or pressure and heat C23C24/04 takes precedence
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23C 6/00 Coating by casting molten material on the substrate
• CPC Class Codes: C25B 11/00 Electrodes; Manufacture thereof not otherwise provided for
• CPC Class Codes: C25D 3/54 of metals not provided for in groups C25D3/04 - C25D3/50
• CPC Class Codes: G21F 9/12 by absorption; by adsorption; by ion-exchange
• CPC Class Codes: H01F 1/0027 Thick magnetic films forming thick magnetic films H01F41/16
• CPC Class Codes: H01F 1/0054 Coated nanoparticles, e.g. nanoparticles coated with organic surfactant
• CPC Class Codes: H01F 1/009 bidimensional, e.g. nanoscale period nanomagnet arrays H01F10/007 takes precedence
• CPC Class Codes: H01F 10/007 ultrathin or granular films H01F10/005 and H01F10/3227 take precedence; applying ultrathin or granular layers to substrates H01F41/301
• CPC Class Codes: H01F 41/24 from liquids
• CPC Class Codes: H01F 41/26 using electric currents , e.g. electroplating
• CPC Class Codes: H01F 41/301 for applying ultrathin or granular layers ultrathin or granular layers H01F10/007
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 2300/0082 : Organic polymers
• CPC Class Codes: H01M 4/02 : Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/86 : Inert electrodes with catalytic activity, e.g. for fuel cells
• CPC Class Codes: H01M 4/8605 : Porous electrodes
• CPC Class Codes: H01M 4/8857 : Casting, e.g. tape casting, vacuum slip casting
• CPC Class Codes: H01M 4/8882 : Heat treatment, e.g. drying, baking
• CPC Class Codes: H01M 4/9083 : on carbon or graphite
• CPC Class Codes: H01M 4/926 : on carbon or graphite
• CPC Class Codes: H01M 8/00 : Fuel cells; Manufacture thereof
• CPC Class Codes: H01M 8/1004 : characterised by membrane-electrode assemblies [MEA] 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 8/249 : comprising two or more groupings of fuel cells, e.g. modular assemblies
• 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

Magnetic composites exhibit distinct flux properties due to gradient interfaces. Such composites can be used, for example, to improve fuel cells and batteries and to effect transport and separation of different chemical species, such as transition metal species (lanthanides and actinides). A variety of devices can be made utilizing the composites, including a separator, an electrode for channeling flux of magnetic species, an electrode for effecting electrolysis of magnetic species, a system for channeling electrolyte species, a system for separating particles with different magnetic susceptibilities, as well as improved fuel cells, batteries, and oxygen concentrators. Various magnetic composites can be used, for example, to make a separator for distinguishing between two chemical species, to form a flux switch to regulate the flow of a chemical species, to control chemical species transport and distribution, to produce rechargeable batteries having longer secondary cycle life and improved output power, and to enable the production of ambient pressure fuel cells having enhanced performance and reduced weight.

Claims

1. A fuel cell, comprising:

a first electrode;

a magnetic composite material on a surface of said first electrode; and

a second electrode,

wherein said first electrode, said magnetic composite material and said second electrode are adapted so that a flux of a magnetic species is establishable between said first electrode and said second electrode when said magnetic species is present between said first and second electrodes.

2. The fuel cell as claimed in claim 1, wherein said magnetic composite material comprises magnetic microbeads, an ion exchange polymer, and carbon particles in association with a catalyst.

3. The fuel cell as claimed in claim 1, wherein said magnetic composite material comprises carbon particles in association with a catalyst.

4. The fuel cell as claimed in claim 3, wherein said catalyst comprises platinum.

5. The fuel cell as claimed in claim 1, wherein said magnetic composite material comprises approximately 10% by weight of magnetic microbeads, and from approximately 10% to approximately 50% by weight of carbon particles in association with a catalyst.

6. The fuel cell as claimed in claim 1, wherein said magnetic composite material comprises a plurality of pillars, wherein each of said plurality of pillars comprises a substantially aligned stack of magnetic microbeads.

7. The fuel cell as claimed in claim 6, wherein each of said plurality of pillars is oriented substantially normal to said surface of said first electrode.

8. The fuel cell as claimed in claim 6, wherein said magnetic microbeads are embedded in an ion exchange polymer.

9. The fuel cell as claimed in claim 1, wherein said magnetic composite material includes particles comprising iron(III) oxide or magnetite.

10. The fuel cell as claimed in claim 9, wherein said particles comprising iron(III) oxide or magnetite are aged.

11. The fuel cell as claimed in claim 9, wherein said particles comprising iron(III) oxide or magnetite are non-coated.

12. A fuel cell, comprising:

a first electrode;

at least one substantially pillared magnetic structure on a surface of said first electrode; and

a second electrode, wherein a flux of oxygen is establishable between said first electrode and said second electrode.

13. The fuel cell as claimed in claim 12, wherein said at least one substantially pillared magnetic structure comprises a plurality of microscopic pillars formed by casting, in an external magnetic field, a casting mixture on said surface of said first electrode, said casting mixture comprising an ion exchange polymer, magnetic microbeads, and carbon particles in association with a catalyst.

14. An ambient pressure fuel cell, comprising:

a first electrode;

at least one substantially pillared magnetic structure on a surface of said first electrode;

a second electrode; and

a fuel source disposed between said first electrode and said second electrode.

15. The ambient pressure fuel cell as claimed in claim 14, wherein constituents of said fuel source have an established transport direction.

16. The fuel cell as claimed in claim 14, wherein said at least one substantially pillared magnetic structure comprises a plurality of microscopic pillars formed by casting a casting mixture on said surface of said first electrode in an external magnetic field, said casting mixture comprising an ion exchange polymer, magnetic microbeads, and carbon particles coated with a catalyst.

17. The fuel cell as claimed in claim 16, wherein said magnetic microbeads comprise iron(III) oxide or magnetite, and wherein said catalyst comprises platinum.

18. A fuel cell, comprising:

a first electrode;

a second electrode; and

a magnetic species between said first electrode and said second electrode;

wherein at least one of said electrodes comprises;

a conductor, and

a magnetic composite material in surface contact with said conductor, said magnetic composite material comprising magnetic microbeads and an ion exchange polymer.

19. The fuel cell of claim 18, wherein said magnetic microbeads are coated with platinum.

20. The fuel cell of claim 18, wherein said magnetic microbeads comprise iron(III) oxide or magnetite, and said magnetic composite material further comprises carbon particles coated with a catalyst.

21. The fuel cell of claim 18, wherein said magnetic composite material comprises approximately 10% by weight of particles comprising iron(III)oxide or magnetite, and from approximately 10% to approximately 50% by weight of carbon particles in association with a catalyst.

22. The fuel cell of claim 18, wherein said magnetic composite material comprises microbeads including iron(III) oxide or magnetite, and wherein said microbeads are encapsulated in a coating material.

23. The fuel cell of claim 18, wherein said magnetic composite material comprises microbeads including iron(III) oxide or magnetite, and wherein said microbeads are non-coated.

24. The fuel cell of claim 18, wherein said magnetic composite material comprises aged iron(III) oxide or aged magnetite.

25. The fuel cell of claim 18, wherein said magnetic composite material has a plurality of transport pathways therethrough, said plurality of transport pathways adapted to enhance a flux of said magnetic species to said conductor.

26. The fuel cell of claim 18, wherein said magnetic composite material includes a plurality of boundary regions therein, wherein each of said plurality of boundary regions is located between a first material having a first magnetic susceptibility and a second material having a second magnetic susceptibility, and wherein each of said plurality of boundary regions has a magnetic gradient therewithin.

27. The fuel cell of claim 26, wherein each of said plurality of boundary regions has a width in the range of from approximately 1 nanometer to approximately 0.5 micrometers.

28. The fuel cell of claim 26, wherein each of said first material and said second material are one of a liquid, a solid, a gas, or a plasma.