Chalcogen-containing compound, its preparation method and thermoelectric element comprising the same

Patent metadata

Field	Value
Publication number	US-11276809-B2
Application number	US-201716312842-A
Country	US
Kind code	B2
Filing date	Oct 17, 2017
Priority date	Oct 31, 2016
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A chalcogen-containing compound that exhibits low thermal conductivity and excellent thermoelectric properties, and exhibits excellent phase stability even at relatively low temperature, a method for preparing the same, and a thermoelectric element including the same.

First claim

The invention claimed is:

1. A chalcogen-containing compound represented by the following Chemical Formula 1:
M x Sn y Bi z Se 7   [Chemical Formula 1]

wherein, in Chemical Formula 1, M is an alkali metal,
x, y and z are mole ratios of M, Sn, and Bi respectively, x is greater than 0.05 and equal to or less than 0.8, y is greater than 3.5 and equal to or less than 4, z is greater than 1.5 and equal to or less than 2, y+z is greater than 5 and equal to or less than 6, and x+y+z is greater than 5 and equal to or less than 6.8.

2. The chalcogen-containing compound according to claim 1 , wherein M is one or more alkali metals selected from the group consisting of Na, and K.

3. The chalcogen-containing compound according to claim 1 , wherein the compound has a crystal structure of a face-centered cubic lattice structure.

4. The chalcogen-containing compound according to claim 3 , wherein M fills a part of a vacancy excluding the sites filled with Se, Sn and Bi in the face-centered cubic lattice structure.

5. The chalcogen-containing compound according to claim 3 , wherein
the Se fills anion sites of the face-centered cubic lattice structure,
the Sn and Bi fill cation sites of the face-centered cubic lattice structure, and
the M fills a part of a vacancy of remaining cation sites, excluding the sites filled with Sn and Bi.

6. The chalcogen-containing compound according to claim 1 , wherein the compound is suitable for use as a thermoelectric conversion material.

7. A method for preparing the chalcogen-containing compound of claim 1 , comprising the steps of:
progressing a solid phase reaction of a mixture comprising raw materials comprising Sn, Bi and Se, and raw material comprising alkali metal;
grinding the product of the solid phase reaction; and
sintering the ground product.

8. The method for preparing a chalcogen-containing compound according to claim 7 , wherein the raw material comprising alkali metal comprises M 2 Se powder, wherein M is an alkali metal.

9. The method for preparing a chalcogen-containing compound according to claim 7 , wherein the raw materials comprising Sn, Bi and Se are each a powder and the raw material comprising alkali metal is a powder, and wherein the solid phase reaction is performed at a temperature of 500 to 700° C., for each powder raw material.

10. The method for preparing a chalcogen-containing compound according to claim 7 , further comprising a step of cooling a product of the solid phase reaction to form an ingot, between the solid phase reaction step and the grinding step.

11. The method for preparing a chalcogen-containing compound according to claim 7 , wherein the sintering step is performed by a spark plasma sintering method.

12. The method for preparing a chalcogen-containing compound according to claim 7 , wherein the sintering step is performed at a temperature of 550° C. or more and a pressure of 10 MPa or more.

13. A thermoelectric element comprising the chalcogen-containing compound according to claim 1 , as a thermoelectric conversion material.

Assignees

• Lg Chemical Ltd

Inventors

• Min Yu Ho
• Park Cheol-Hee

Classifications

• C01P2004/38

  cube-like · CPC title

• C01P2002/77

  by unit-cell parameters, atom positions or structure diagrams · CPC title

• C01P2006/40

  Electric properties · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01P2006/32

  Thermal properties · CPC title