Thermoelectric material and preparation method therefor
The present invention relates to a thermoelectric material and, specifically, to a thermoelectric material capable of improving the figure of merit and a preparation method therefor. In the present invention, the thermoelectric material may comprise: a matrix compound having a composition of chemical formula 1 or 2; and particles having a composition of chemical formula 3 dispersed in the matrix compound. (AB 2 ) x (Bi 2 Se 2.7 Te 0.3 ) 1-x , (CB) x (Bi 2 Se 2.7 Te 0.3 ) 1-x , D y E z .
1. A thermoelectric material comprising:
a matrix compound having a composition of Chemical Formula 1 or Chemical Formula 2 below;
nanoparticles having a composition of Chemical Formula 3 dispersed in the matrix compound, wherein the nanoparticles have a tellurium (Te)-based composition; and
grains having crystal orientation directions aligned in a same direction,
where:
(AB 2 ) x (Bi 2 Se 2.7 Te 0.3 ) 1-x , <Chemical Formula 1>
where A is a divalent cation element, B is a monovalent anion element, and x satisfies 0 <x≤0.4,
(CB) x (Bi 2 Se 2.7 Te 0.3 ) 1-x , <Chemical Formula 2>
where C is a monovalent cation element, B is a monovalent anion element, and x satisfies 0 <x≤0.4, and
Cu 2 Te, <Chemical Formula 3>
wherein the copper (Cu) is contained in an amount of 1 to 5% by weight of the matrix compound and the tellurium (Te) is contained in an amount of 20 to 25% by weight of the matrix compound, and
wherein the nanoparticles are dispersed in the matrix compound in an amount of 26 to 30% by weight of the matrix compound and the thermoelectric material has an average grain size of 5 to 6 micron.
2. The thermoelectric material of claim 1 , wherein in Chemical Formula 1, A is any one selected from a group consisting of Cu, Ag, and a compound thereof.
3. The thermoelectric material of claim 1 , wherein in Chemical Formula 2, C is any one selected from a group consisting of Fe, Mn, Co, Cr, V, Nb, and compounds thereof.
4. The thermoelectric material of claim 1 , wherein the matrix compound has a layered structure.
5. The thermoelectric material of claim 4 , wherein the layered structure comprises:
a first layer containing Te; and
a second layer containing Bi.
6. The thermoelectric material of claim 1 ,
wherein the crystal orientation directions are aligned in a material usage direction of the thermoelectric material.
7. The thermoelectric material of claim 1 , wherein the nanoparticles are formed from a ribbon-shaped intermediate having a thickness of about 1 μm to 100 μm.
8. The thermoelectric material of claim 1 , wherein a doped CuI is distributed in a state of Cu+ and I− in a unit cell to generate an electric field in the thermoelectric material.