Thermoelectric compositions and process

Abstract

A process for producing bulk thermoelectric compositions containing nanoscale inclusions is described. The thermoelectric compositions have a higher figure of merit (ZT) than without the inclusions. The compositions are useful for power generation and in heat pumps for instance.

1 . A thermoelectric composition comprising:
 a matrix comprising a first chalcogenide; and   nanoscale inclusions in the matrix, the nanoscale inclusions being coherent or semi-coherent with the matrix, the nanoscale inclusions having a different composition than the first chalcogenide, so that the nanoscale inclusions decrease the thermal conductivity of the composition by scattering phonons in the composition while substantially maintaining or increasing electrical conductivity and Seebeck coefficient of the composition.   
     
     
         2 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions are coherent with the matrix. 
     
     
         3 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions have a first melting point, the matrix has a second melting point, and the first melting point is lower than the second melting point. 
     
     
         4 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions have a first melting point, the matrix has a second melting point, and the second melting point is lower than the first melting point. 
     
     
         5 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions have a first melting point, the matrix has a second melting point, and the first melting point is different than the second melting point. 
     
     
         6 . The thermoelectric composition of  claim 1 , wherein at least a portion of the nanoscale inclusions are a uniform dispersion of nanoparticles. 
     
     
         7 . The thermoelectric composition of  claim 1 , wherein about 0.1 to 15% of the composition comprises the nanoscale inclusions. 
     
     
         8 . The thermoelectric composition of  claim 1 , wherein at least a portion of the nanoscale inclusions comprise a material that is nonreactive, has a lower melting point, and is soluble with the matrix in a liquid state. 
     
     
         9 . The thermoelectric composition of  claim 1 , wherein the first chalcogenide comprises a chalcogen selected from the group consisting of tellurium, sulfur and selenium. 
     
     
         10 . The thermoelectric composition of  claim 1 , wherein at least a portion of the nanoscale inclusions have a size between about 1 and 200 nanometers. 
     
     
         11 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions comprise multiple types of inclusions, each type having a different chemistry. 
     
     
         12 . The thermoelectric composition of  claim 1 , wherein the composition has lattice thermal conductivity which is more than 40% reduced as compared to lattice thermal conductivity of the matrix. 
     
     
         13 . The thermoelectric composition of  claim 1 , wherein the matrix comprises PbTe. 
     
     
         14 . The thermoelectric composition of  claim 13 , wherein the nanoscale inclusions comprise PbS. 
     
     
         15 . The thermoelectric composition of  claim 13 , wherein the nanoscale inclusions comprise at least one element selected from the group consisting of antimony, bismuth, and arsenic. 
     
     
         16 . The thermoelectric composition of  claim 13 , wherein the nanoscale inclusions comprise lead and antimony. 
     
     
         17 . The thermoelectric composition of  claim 13 , wherein the nanoscale inclusions comprise Cd 1-x Hg x Te and 0<x<1. 
     
     
         18 . The thermoelectric composition of  claim 1 , wherein the matrix comprises PbS and the nanoscale inclusions comprise PbTe. 
     
     
         19 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions comprise a metal. 
     
     
         20 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions comprise a semiconductor. 
     
     
         21 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions comprise a second chalcogenide different from the first chalcogenide, the second chalcogenide comprising a chalcogen selected from the group consisting of tellurium, sulfur and selenium. 
     
     
         22 . The thermoelectric composition of  claim 1 , wherein the matrix comprises PbQ, and the Q component comprises at least one element selected from the group consisting of: tellurium, selenium, and sulfur. 
     
     
         23 . The thermoelectric composition of  claim 1 , wherein the matrix comprises SnQ, and the Q component comprises at least one element selected from the group consisting of: tellurium and selenium. 
     
     
         24 . The thermoelectric composition of  claim 1 , wherein the nanoscale inclusions do not act as a strong scatterer to electrons. 
     
     
         25 . The thermoelectric composition of  claim 1 , wherein at least a portion of the inclusions in the matrix are thermally stable to a temperature higher than 650 K. 
     
     
         26 . The thermoelectric composition of  claim 1 , wherein the composition comprises a bulk composition. 
     
     
         27 . A thermoelectric composition comprising:
 a matrix comprising a first chalcogenide; and   nanoscale inclusions in the matrix, the nanoscale inclusions have a first melting point, the matrix has a second melting point, the first melting point is lower than the second melting point, the nanoscale inclusions having a different composition than the first chalcogenide, so that the nanoscale inclusions decrease the thermal conductivity of the composition by scattering phonons in the composition while substantially maintaining or increasing electrical conductivity and Seebeck coefficient of the composition.   
     
     
         28 . A thermoelectric composition comprising:
 a matrix comprising a first chalcogenide; and   nanoscale inclusions in the matrix, the nanoscale inclusions comprise a second chalcogenide different from the first chalcogenide, the second chalcogenide comprising a chalcogen selected from the group consisting of tellurium, sulfur and selenium, so that the nano scale inclusions decrease the thermal conductivity of the composition by scattering phonons in the composition while substantially maintaining or increasing electrical conductivity and Seebeck coefficient of the composition.