THERMOELECTRIC COMPOSITIONS AND METHODS OF FABRICATING HIGH THERMOELECTRIC PERFORMANCE MgAgSb-BASED MATERIALS

Abstract

Systems and methods of manufacturing a thermoelectric, high performance material by using ball-milling and hot pressing materials according to various formulas, where some formulas substitute a different element for part of one of the elements in the formula, in order to obtain a figure of merit (ZT) suitable for thermoelectric applications.

What is claimed: 
     
         1 . A method of manufacturing a thermoelectric material comprising:
 ball-milling a plurality of components to form at least one powder;   forming a pressed component by hot-pressing the at least one powder; and   annealing the pressed component, wherein the pressed component comprises a ZT value of at least 0.85 at room temperature.   
     
     
         2 . The method of  claim 1 , wherein a first component of the plurality of components comprises magnesium (Mg), silver (Ag), antimony (Sb), copper (Cu), or nickel (Ni), wherein a second component of the plurality of components is one of magnesium (Mg), silver (Ag), antimony (Sb), copper (Cu), or nickel (Ni), and wherein the second component is not the same as the first component. 
     
     
         3 . The method of  claim 1 , wherein a third component of the plurality of components comprises magnesium (Mg), silver (Ag), antimony (Sb), copper (Cu), or nickel (Ni), wherein the third component different than the first component and the second component, wherein a fourth component of the plurality of components magnesium (Mg), silver (Ag), antimony (Sb), copper (Cu), chromium (Cr), zinc (Zn), or nickel (Ni), and wherein the fourth component different than the first component, the second component, and the third component. 
     
     
         4 . The method of  claim 1 , wherein hot-pressing the powder comprises holding the second mixture at a temperature from about 125° C. to about 300° C. for a period of about 0.5 minutes to about 20 minutes. 
     
     
         5 . The method of  claim 2 , wherein the first component is Mg, the second component is Ag, and wherein a ratio of the first component to the second component is about 1.1. 
     
     
         6 . The method of  claim 5 , wherein the ratio of the first component to the second component is such that both components are in the range of about 0.9-1.1. 
     
     
         7 . The method of  claim 1 , wherein annealing the pressed component comprises holding the pressed component at a temperature from about 125° C. to about 300° C. from about 0.1 hours to about 100 hours. 
     
     
         8 . A thermoelectric material comprising:
 a thermoelectric material according to the formula X 1-n A n Y 1-m B m Z 1-q C q  wherein X, Y, and Z are each one of magnesium (Mg), silver (Ag), and antimony (Sb), and wherein the ZT of the thermoelectric material is at least 0.5 at room temperature.   
     
     
         9 . The thermoelectric material of  claim 8 , wherein n, m, and q are each from about 0.0001 to about 0.5000. 
     
     
         10 . The thermoelectric material of  claim 8 , wherein at least one of n, m, and q is zero. 
     
     
         11 . The thermoelectric material of  claim 8 , wherein C comprises one of aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), bismuth (Bi), selenium (Se), and tellurium (Te), and alloys and combinations thereof. 
     
     
         12 . The thermoelectric material of  claim 8 , wherein X comprises at least one element selected from the lanthanoid group. 
     
     
         13 . A method of manufacturing a thermoelectric material comprising:
 forming a first mixture by ball-milling a first component and a second component for a period from about 10 minutes to about 50 hours;   disposing a third component in the first mixture;   forming a second mixture by ball-milling the third component and the first mixture for a period from about 10 minutes to about 50 hours;   disposing a fourth component into the second mixture;   forming a third mixture by ball-milling the fourth component and the second mixture for a period from about 10 minutes to about 50 hours;   forming a pressed component by hot-pressing the third mixture; and   wherein the thermoelectric material comprises a ZT of at least 0.75 at room temperature.   
     
     
         14 . The method of  claim 13 , wherein the first component comprises magnesium (Mg), wherein the second component comprises silver (Ag), wherein the third component comprises antimony (Sb), and wherein the fourth component comprises one of nickel (Ni), (copper) Cu, zinc (Zn), gold (Au), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), and alloys and combinations thereof. 
     
     
         15 . A thermoelectric material comprising:
 a plurality of components according to the composition Mg w Ag y-x Cu x Sb 0z  wherein x is from about to 0.005 about 0.01.   
     
     
         16 . The thermoelectric material of  claim 15 , further comprising a ZT of at least 0.5 from at about 50° C. to about 250° C.