Compositions and methods for thermoelectric ceramics
In one aspect, the disclosure relates to thermoelectric ceramic oxide compositions comprising a CaMnO 3 ceramic. In a further aspect, the disclosed thermoelectric ceramic oxide compositions can dramatically increase the energy conversion efficiency of thermoelectric through a combination of modifying the chemistry of precursor materials, and simultaneously introducing a metal oxide liquid phase during sintering. In a further aspect, the present disclosure pertains to thermoelectric ceramic oxide compositions comprising a metal doped CaMnO 3 having with a metal oxide grain boundary phase; wherein the metal is selected from group 13, group 14, group 15, group 16, or a rare earth element. In a still further aspect, the disclosure relates to methods for making the thermoelectric ceramic oxide materials. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
1. A thermoelectric ceramic oxide comprising: bismuth doped CaMnO 3 with a copper oxide grain boundary phase; wherein the ceramic oxide has the molecular formula Ca 1-x Bi x MnCu y O 3 ; wherein x has a value of 0.01 to 0.1; and wherein y has a value of 0.01 to 0.2.
2. The thermoelectric ceramic oxide of claim 1 , wherein the figure of merit is greater than 0.3.
3. The thermoelectric ceramic oxide of claim 1 , wherein the figure of merit is approximately 0.67.
4. The thermoelectric ceramic oxide of claim 1 , wherein the copper oxide grain boundary phase is formed by liquid phase sintering of copper oxide.
5. The thermoelectric ceramic oxide of claim 1 , wherein the ceramic oxide molecular formula is Ca 1-x Bi x MnCu y O 3 , wherein the ceramic oxide has the molecular formula Ca 1-x Bi x MnCu y O 3 wherein x is one of the values consisting of 0.02, 0.03 and 0.04, and y is one of the values consisting of 0.02 and 0.04.
6. A thermoelectric ceramic oxide comprising a composition having a molecular formula Ca 1-x M x MnCu y O 3 ; wherein M is an element selected from group 13, group 14, group 15, group 16, or a rare earth element; wherein x is a number having a value from about 0.01 to about 0.5; wherein y is a number having a value from about 0.01 to about 0.5; and wherein the thermoelectric ceramic oxide has a grain boundary phase comprising copper oxide.
7. The thermoelectric ceramic oxide of claim 6 , wherein M is bismuth.
8. The thermoelectric ceramic oxide of claim 6 , wherein M is cerium.
9. The thermoelectric ceramic oxide of claim 6 , wherein M is lutetium.
10. The thermoelectric ceramic oxide of claim 6 , wherein M is ytterbium.
11. The thermoelectric ceramic oxide of claim 6 , wherein M is niobium.
12. The thermoelectric ceramic oxide of claim 6 , wherein M is an element selected from Bi, Nb, Yb, Dy, Mo, W, and Gd.
13. A method of making a high performance, thermoelectric ceramic oxide comprising the steps of:
doping a ceramic oxide formulation with a first metal and a second metal in a sol-gel process resulting in a gel;
heating the gel to form an ash-based powder;
grinding the ash;
calcining the ground ash to form a powder;
pressing the powder to form a pellet; and
sinterng the pellet to form the high performance, thermoelectric ceramic oxide with a grain boundary phase that comprises an oxide of the second metal.
14. The method of claim 13 , wherein the first metal is bismuth and second metal is copper.
15. The method of claim 13 , wherein the high performance, ceramic oxide has the molecular formula Ca 1-x Bi x MnCu y O 3 wherein x is one of the values consisting of 0.02, 0.03 and 0.04, and y is one of the values consisting of 0.02 and 0.04.