Non-stoichiometric bismuth telluride-based thermoelectric material and preparation method thereof

A non-stoichiometric ratio, bismuth telluride-based technology, applied in the direction of thermoelectric device junction lead-out materials, etc., can solve the problems of reducing the electrical properties of materials, unfavorable carrier transport, poor repeatability, etc., and achieve favorable electron transport , no risk of high temperature, high repetition rate effect

Active Publication Date: 2020-12-04
TSINGHUA UNIV
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  • Application Information

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Problems solved by technology

However, the grain size directly prepared by this method is too small, which is not conducive to the transport of carriers, so the electrical properties of the material will be reduced to a certain extent.
Kim et al. (Science, Vol.348, 2015, 109-114) reported a method of adding excess Te elemental substance to the raw material to form a eutectic liquid in the process of discharge plasma sintering after melt spinning. Phase and extruded preparation method, but the reproducibility of this method is extremely poor

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  • Non-stoichiometric bismuth telluride-based thermoelectric material and preparation method thereof
  • Non-stoichiometric bismuth telluride-based thermoelectric material and preparation method thereof
  • Non-stoichiometric bismuth telluride-based thermoelectric material and preparation method thereof

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preparation example Construction

[0040] The preparation method of the non-stoichiometric bismuth telluride-based thermoelectric material proposed by the present invention comprises the following steps:

[0041] (1) According to the chemical composition of the bismuth telluride-based thermoelectric material as claimed in claim 1, take Bi elemental powder, Sb elemental particle and Te elemental powder raw material, put into ball mill jar and pass into protective gas, carry out ball milling process , to get powder;

[0042] (2) Putting the powder obtained in step (1) into a graphite mold, applying pressure in a vacuum to perform cyclic discharge plasma sintering with repeated temperature rise and fall, to obtain a bismuth telluride-based thermoelectric material block.

[0043] In the above preparation method, the purity of the Bi elemental powder and the Sb elemental particles is greater than or equal to 99.99%, and the purity of the Te elemental powder is 99.999%, by mass.

[0044] In the above preparation met...

Embodiment 1

[0065] Bi according to the chemical formula 0.45 Sb 1.55 Te 3.2 (i.e. general formula Bi x Sb 2-x Te 3+y The stoichiometric ratio of x=0.45, y=0.2) takes by weighing 15g of the raw material mixture, specifically 2.0366 grams of Bi elemental powder (purity is 99.99%), Sb elemental particles (purity is 99.99%) 4.0948 grams, Te elemental Powder (99.999% pure) 8.8687 g.

[0066] Put the weighed mixture into a stainless steel ball milling jar, wherein the mass ratio of stainless steel balls to raw materials is 20:1, and fill the ball milling jar with argon-hydrogen mixed gas as a protective gas, wherein the hydrogen volume content is 5%, and the argon The gas volume content is 95%, and ball milled at a speed of 450 r / min for 6 hours in a planetary ball mill (QM-3SP2, Nanjing University Instrument Factory).

[0067] Put the above-prepared powder into a graphite mold, put it into a spark plasma sintering furnace (SPS) after compaction, and raise it to 420 ° C in 7 minutes in th...

Embodiment 2

[0071] Bi according to the chemical formula 0.45 Sb 1.55 Te 3.2 (i.e. general formula (1) Bi x Sb 2-x Te 3+yThe stoichiometric ratio of x=0.45, y=0.2) takes by weighing 15g of the raw material mixture, specifically 2.0366 grams of Bi elemental powder (purity is 99.99%), Sb elemental particles (purity is 99.99%) 4.0948 grams, Te elemental Powder (99.999% pure) 8.8687 g.

[0072] Put the weighed mixture into a stainless steel ball milling jar, wherein the mass ratio of stainless steel balls to raw materials is 20:1, and fill the ball milling jar with argon-hydrogen mixed gas as a protective gas, wherein the hydrogen volume content is 5%, and the argon The gas volume content is 95%, and ball milled at a speed of 450 r / min for 6 hours in a planetary ball mill (QM-3SP2, Nanjing University Instrument Factory).

[0073] Put the above-prepared powder into a graphite mold, put it into a spark plasma sintering furnace (SPS) after compaction, and raise it to 420 ° C in 7 minutes in...

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Abstract

The invention belongs to the technical field of energy materials, and particularly relates to a non-stoichiometric bismuth telluride-based thermoelectric material and a preparation method thereof. Thematerial disclosed by the invention has a chemical composition shown as the following general formula: BixSb2xTe3+y, and the preparation method comprises the following steps: firstly, weighing Bi simple substance powder, Sb simple substance particles and Te simple substance powder raw materials according to the chemical composition of the general formula, carrying out ball milling treatment to obtain powder, and carrying out cyclic discharge plasma sintering treatment on the obtained powder for 1-5 times to obtain a block sample. The bismuth telluride-based thermoelectric material prepared bythe method is good in crystallinity and compact in structure, and compared with a sample prepared by a traditional mechanical alloying and sintering combined method, the bismuth telluride-based thermoelectric material is obviously increased in grain size and introduces a large number of dislocations, so that the electrical property is improved, the lattice thermal conductivity is reduced, and thethermoelectric property is excellent. Meanwhile, the preparation method is simple and convenient to operate, short in period, free of high-temperature risk and low in energy consumption, and has a wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of energy materials, and in particular relates to a non-stoichiometric bismuth telluride-based thermoelectric material and a preparation method thereof. Background technique [0002] Thermoelectric materials can realize the mutual conversion of heat energy and electric energy, and have great potential in alleviating the energy crisis and realizing solid-state refrigeration. Compared with the traditional thermal and electrical energy conversion methods, it has the advantages of no mechanical vibration and easy miniaturization. However, due to performance limitations, it is still difficult to achieve large-scale applications. Therefore, improving the performance of thermoelectric materials is a top priority for research. The performance measurement standard of thermoelectric materials is the dimensionless thermoelectric figure of merit ZT value, and its expression is: ZT=σS 2 T / κ, where σ is electrical conduc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/547C04B35/622H01L35/16
CPCC04B35/547C04B35/622C04B2235/42C04B2235/40C04B2235/602C04B2235/656C04B2235/6562C04B2235/6565C04B2235/6567C04B2235/6581C04B2235/666H10N10/852
Inventor 李敬锋庄华鹭
Owner TSINGHUA UNIV
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