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

Patent metadata

Field	Value
Publication number	US-11306004-B2
Application number	US-201816463300-A
Country	US
Kind code	B2
Filing date	May 11, 2018
Priority date	Jun 27, 2017
Publication date	Apr 19, 2022
Grant date	Apr 19, 2022

Abstract

A chalcogen-containing compound of the following Chemical Formula 1 which exhibits excellent phase stability at a temperature corresponding to the driving temperature of a thermoelectric element, and also exhibits an excellent thermoelectric performance index (ZT) through an increase in a power factor and a decrease in thermal conductivity, a method for preparing the same, and a thermoelectric element including the same:

V 1-x M x Sn 4-y Pb y Bi 2 Se 7-z Te z   [Chemical Formula 1]

In the above Formula 1, V is a vacancy, M is an alkali metal, x is greater than 0 and less than 1, y is greater than 0 and less than 4, and z is greater than 0 and less than or equal to 1.

First claim

The invention claimed is:

1. A chalcogen-containing compound represented by the following Chemical Formula 1:
V 1-x M x Sn 4-y Pb y Bi 2 Se 7-z Te z   [Chemical Formula 1]

wherein, in the above Formula 1, V is a vacancy, M is an alkali metal, x is greater than 0 and less than 1, y is greater than 0 and less than 4, and z is greater than 0 and less than or equal to 1,
wherein the chalcogen-containing compound has a face-centered cubic crystal lattice structure,
the Se is filled in an anion site of the face-centered cubic lattice structure,
the Sn, Pb, and Bi are filled in a cation site of the face-centered cubic lattice structure,
the Pb is substituted by replacing a part of the Sn,
the Te is substituted by replacing a part of the Se,
the M is filled in at least some of vacant sites excluding the sites filled with Sn, Pb, Bi, Se, and Te in the face-centered cubic lattice structure, and
the V is a vacant site of the remaining cationic sites.

2. The chalcogen-containing compound of claim 1 , wherein the M is at least one alkali metal selected from the group consisting of Li, Na, and K.

3. The chalcogen-containing compound of claim 1 , wherein the V, M, Sn, Pb, and Bi are randomly distributed at the site of (x, y, z)=(0, 0, 0), and Se and Te are randomly distributed at the site of (x, y, z)=(0.5, 0.5, 0.5).

4. The chalcogen-containing compound of claim 1 , wherein the x+y+z is greater than 0 and less than or equal to 5.

5. The chalcogen-containing compound of claim 1 , wherein the compound is selected from the group consisting of V 0.8 Na 0.2 Sn 3.2 Pb 0.8 Bi 2 Se 6.95 Te 0.05 , V 0.8 Na 0.2 Sn 3.2 Pb 0.8 Bi 2 Se 6.6 Te 0.4 , and V 0.8 Na 0.2 Sn 3.2 Pb 0.8 Bi 2 Se 6.2 Te 0.8 .

6. A method for preparing the chalcogen-containing compound of claim 1 , represented by the following Chemical Formula 1:
V 1-x M x Sn 4-y Pb y Bi 2 Se 7-z Te z   [Chemical Formula 1]

wherein, in the above Formula 1, V is a vacancy, M is an alkali metal, x is greater than 0 and less than 1, y is greater than 0 and less than 4, and z is greater than 0 and less than or equal to 1,
comprising the steps of:
mixing raw materials of Sn, Pb, Bi, Se, Te, and an alkali metal (M) and subjecting the mixture to a melting reaction;
heat-treating the resultant product obtained through the melting reaction;
pulverizing the resultant product obtained through the heat treatment; and
sintering the pulverized product,
wherein the mixing of raw materials is carried out by mixing the raw materials such that the molar ratio of Sn, Pb, Bi, Se, Te, and an alkali metal (M) is a ratio corresponding to 4-y:y:2:7-z:z:x.

7. The method for preparing the chalcogen-containing compound of claim 6 , wherein the melting is carried out at a temperature of 700° C. to 800° C.

8. The method for preparing the chalcogen-containing compound of claim 6 , wherein the heat treatment is carried out at a temperature of 550° C. to 640° C.

9. The method for preparing the chalcogen-containing compound of claim 6 , further comprising a step of cooling the result of the heat treatment step to form an ingot between the heat treatment step and the pulverization step.

10. The method for preparing the chalcogen-containing compound of claim 6 , wherein the sintering step is carried out by a spark plasma sintering method.

11. The method for preparing the chalcogen-containing compound of claim 6 , wherein the sintering step is carried out at a temperature of 550° C. to 700° C. under a pressure of 10 MPa to 100 MPa.

12. A thermoelectric element comprising the chalcogen-containing compound according to claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Kim Min Kyoung
• Min Yu Ho
• Park Cheol Hee
• Ko Kyung Moon
• Park Chee Sung
• Kim Jae Hyun
• Jung Myung Jin

Classifications

• C01P2002/30

  Three-dimensional structures · CPC title

• C01P2006/40

  Electric properties · CPC title

• C01B19/00

  Selenium; Tellurium; Compounds thereof (phosphorus compounds C01B25/14) · CPC title

• C01B19/002 Primary

  Compounds containing, besides selenium or tellurium, more than one other element, with -O- and -OH not being considered as anions · CPC title

• C01P2006/32

  Thermal properties · CPC title