ZrCoBi based half Heuslers with high thermoelectric conversion efficiency
A ZrCoBi-based p-type half-Heusler material can have a formula: ZrCoBi 1-x-y Sn x Sb y , where x can vary between 0.01 and 0.25, and y can vary between 0 and 0.2. An average dimensionless figure-of-merit (ZT) for the material can be greater than or equal to about 0.80 as calculated by an integration method for temperatures between 300 and 973 K. A ZrCoBi-based n-type half-Heusler material can have a formula: ZrCo 1-x Ni x Bi 1-y Sb y , where x can vary between 0.01 and 0.25, and y can vary between 0 and 0.3. The material has an average dimensionless figure-of-merit (ZT) is greater than or equal to about 0.65 as calculated by an integration method for temperatures between 300 and 973 K.
1. A ZrCoBi-based p-type half-Heusler material comprising:
a material having a formula:
ZrCoBi 1-x-y Sn x Sb y ,
where x can vary between 0.01 and 0.25, and y can vary between 0 and 0.2.
2. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein x is 0.2 and y is 0.15, wherein an average dimensionless figure-of-merit (ZT) of the material is greater than or equal to about 0.80 as calculated by an integration method for temperatures between 300 and 973 K.
3. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein an average dimensionless figure-of-merit (ZT) of the material is greater than or equal to about 0.80 as calculated by an integration method for temperatures between 300 and 973 K.
4. The ZrCoBi-based p-type half-Heusler material of claim 1 , where a peak dimensionless figure-of-merit (ZT) of the material is greater than or equal to about 1.4 at 973 K.
5. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein a thermoelectric conversion efficiency of the material is greater than or equal to about 9% at a temperature difference of about 500K.
6. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein the material has a band structure with a high band degeneracy (N ν ) of at least about 10.
7. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein the material has a room temperature power factor of at least about 20 μW cm −1 K −2 , and wherein the material has a peak power factor of at least about 40 μW cm −1 K −2 .
8. The ZrCoBi-based p-type half-Heusler material of claim 7 , wherein x varies between 0.15 and 0.2 and y is 0.
9. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein the material has a room temperature lattice thermal conductivity of less than 3 W m −1 K −1 .
10. The ZrCoBi-based p-type half-Heusler material of claim 1 , wherein the material has a mean sound velocity (ν m ) of less than about 2800 m s −1 .
11. A ZrCoBi-based n-type half-Heusler material comprising:
a material having a formula:
ZrCo 1-x Ni x Bi 1-y Sb y ,
where x can vary between 0.01 and 0.25, and y can vary between greater than 0 and less than or equal to 0.3.
12. The ZrCoBi-based n-type half-Heusler material of claim 11 , wherein x is 0.1 and y is 0.15.
13. The ZrCoBi-based n-type half-Heusler material of claim 11 , wherein the material has an average dimensionless figure-of-merit (ZT) of greater than or equal to about 0.65 as calculated by an integration method for temperatures between 300 and 973 K.
14. The ZrCoBi-based n-type half-Heusler material of claim 11 , where a peak dimensionless figure-of-merit (ZT) of the material is greater than or equal to about 1.0 at 973 K.
15. The ZrCoBi-based n-type half-Heusler material of claim 11 , wherein a thermoelectric conversion efficiency of the material is greater than or equal to about 7% at a temperature difference of about 650K.
16. A thermoelectric module comprising:
at least one first leg, wherein the at least one first leg comprises a first material having a formula:
ZrCoBi 1-x-y Sn x Sb y ,
where x can vary between 0.01 and 0.25, and y can vary between 0 and 0.2; and
at least one second leg, wherein the at least one second leg comprises a second material having a formula:
ZrCo 1-a Ni a Bi 1-b Sb b ,
where a can vary between 0.01 and 0.25, and b can vary between greater than 0 and less than or equal to 0.3;
wherein the at least one first leg and the at least one second leg are connected thermally in parallel and electrically in series.
17. The thermoelectric module of claim 16 , wherein the module has a thermoelectric conversion efficiency of 10% or greater at a temperature difference of about 650 K.
18. The thermoelectric module of claim 16 , where a peak dimensionless figure-of-merit (ZT) of the first material is greater than or equal to about 1.4 at 973 K.
19. The thermoelectric module of claim 16 , where a peak dimensionless figure-of-merit (ZT) of the second material is greater than or equal to about 1.0 at 973 K.
20. The thermoelectric module of claim 16 , wherein a thermoelectric conversion efficiency of the first material is greater than or equal to about 9% at a temperature difference of about 500 K, and wherein a thermoelectric conversion efficiency of the second material is greater than or equal to about 7% at a temperature difference of about 650 K.