Nanostructured bulk thermoelectric material

• US 20060118158A1
• Filed: 05/03/2005
• Published: 06/08/2006
• Est. Priority Date: 05/03/2005
• Status: Active Grant

• Current Assignee: Administrators Of The Tulane Educational Fund (ADMINISTRATORS|DAVID H. COY), Toyota Motor Corporation, Tulane University
• Original Assignee: Toyota Motor Corporation
• Inventors: Lu, Yunfeng, Zhang, Minjuan
• Granted Patent: US 7,309,830 B2
• Time in Patent Office: Days
• US Class Current: 136/205
• CPC Class Codes: C02F 1/02 by heating methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D
• CPC Class Codes: C02F 2103/02 Non-contaminated water, e.g. for industrial water supply
• CPC Class Codes: H10N 10/01 Manufacture or treatment
• CPC Class Codes: H10N 10/852 comprising tellurium, selenium or sulfur
• CPC Class Codes: H10N 10/857 comprising compositions changing continuously or discontinuously inside the material

Abstract

A thermoelectric material comprises two or more components, at least one of which is a thermoelectric material. The first component is nanostructured, for example as an electrically conducting nanostructured network, and can include nanowires, nanoparticles, or other nanostructures of the first component. The second component may comprise an electrical insulator, such as an inorganic oxide, other electrical insulator, other low thermal conductivity material, voids, air-filled gaps, and the like. Additional components may be included, for example to improve mechanical properties. Quantum size effects within the nanostructured first component can advantageously modify the thermoelectric properties of the first component. In other examples, the second component may be a thermoelectric material, and additional components may be included.

Claims

1. A thermoelectric device, comprising:

a first electrical contact;

a second electrical contact; and

a thermoelectric material located within an electrical path between the first electrical contact and the second electrical contact, the thermoelectric material including;

a first component,

a second component, the second component having an electrical conductivity substantially less than the first component,

the thermoelectric material including nanostructures of the first component.

2. The thermoelectric device of claim 1, wherein the thermoelectric material is a composite including nanostructures of the first component.

3. The thermoelectric device of claim 2, wherein the first component is a semiconductor.

4. The thermoelectric device of claim 2, wherein the first component is a metal.

5. The thermoelectric device of claim 1, wherein the second component is an electrical insulator.

6. The thermoelectric device of claim 1, wherein the first component is a semiconductor, and the second component is an electrically insulating inorganic oxide.

7. The thermoelectric device of claim 1, wherein the first component is a semiconductor, the semiconductor forming an electrically conducting nanostructured network through the second component.

8. The thermoelectric device of claim 1, wherein an electrically conducting nanostructured network of the first component extends through nanopores within an electrically insulating matrix formed by the second component.

9. The thermoelectric device of claim 1, the device providing an electrical potential between the first electrical contact and the second electrical contact when a thermal gradient extends over at least part of the device including the thermoelectric material.

10. A thermoelectric material comprising:

a first component, the first component being electrically conducting; and

a second component, the second component having an electrical conductivity substantially less than the first component;

the first component forming an electrically conducting nanostructured network,

the thermoelectric material providing an electrical potential in response to a thermal gradient applied across the thermoelectric material, or a thermal gradient in response to an electric potential applied across the thermoelectric material.

11. The thermoelectric material of claim 10, wherein the thermoelectric material is a thick film or bulk material having a smallest physical dimension of greater than 1 mm.

12. The thermoelectric material of claim 10, wherein the electrical conductivity of the first component is over 100 times greater than the electrical conductivity of the second component.

13. The thermoelectric device of claim 10, wherein the electrically conducting nanostructured network is a three-dimensional continuous network.

14. The thermoelectric material of claim 10, wherein the first component is a semiconductor, and the second component is an electrical insulator.

15. The thermoelectric material of claim 10, wherein the electrically conducting nanostructured network is a three-dimensional network extending through nanopores of a matrix including the second component.

16. The thermoelectric device of claim 10, wherein the thermoelectric material is a composite material formed from powder, the powder including nanostructures of the first component.

17. The thermoelectric material of claim 16, wherein the powder includes particles having an internal nanostructure of the first component.

18. The thermoelectric material of claim 10, wherein

the first component is a semiconductor compound including selenium or tellurium, and

the second component is an electrically insulating inorganic oxide.

19. The thermoelectric material of claim 10, wherein:

the first component is chosen from a group consisting of tellurium-containing semiconductors, selenium-containing semiconductors, and silicon-germanium alloys; and

the second component includes a material chosen from a group consisting of alumina, lanthanum cobaltate, sodium cobaltate, silica, tin oxide, zinc oxide, zirconium oxide, yttrium oxide, fullerenes, carbon nanotubes, nitrogen, and air.

20. The thermoelectric material of claim 10, wherein the first component includes bismuth telluride, and second component includes silica.

21. The thermoelectric material of claim 10, wherein a thermoelectric coefficient of the first component within the thermoelectric material is enhanced by a quantum size effect.

22. The thermoelectric material of claim 10, wherein the thermoelectric material comprises semiconductor nanoparticles and particles of an electrically insulating material.

23. A process of forming a thermoelectric material, the process comprising:

providing a porous electrically insulating material;

incorporating an electrical conductor into pores of the electrically insulating material, so as to provide a thermoelectric material comprising an electrically conducting nanostructured network extending through the electrically insulating material.

24. The process of claim 23, wherein the porous electrically insulating material is a nanoporous electrically insulating inorganic oxide.

25. The process of claim 23, wherein providing a nanoporous electrically insulating material further includes forming the nanoporous electrically insulating material using a process including self-assembly of amphiphilic molecules.

26. The process of claim 23, wherein incorporating an electrical conductor or semiconductor into nanopores of the electrically insulating material includes an electrodeposition process.

27. A process of forming a thermoelectric material, the method comprising:

providing a powder mixture, the powder mixture including particles comprising an electrical conductor, and particles comprising an electrical insulator;

pressing the powder mixture to form the thermoelectric material, the formed thermoelectric material including nanostructures of the electrical conductor.

28. The process of claim 27, wherein the electrical conductor is a semiconductor.

29. The process of claim 27, wherein the method further includes heating the powder mixture.