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CN-122003089-A - Composite P-type bismuth telluride base material and preparation method thereof

CN122003089ACN 122003089 ACN122003089 ACN 122003089ACN-122003089-A

Abstract

The invention belongs to the technical field of thermoelectric materials, and provides a composite P-type bismuth telluride based material and a preparation method thereof, wherein the composite P-type bismuth telluride based material comprises a P-type bismuth telluride matrix with a chemical formula of Bi 0.5 Sb 1.5 Te 3.2 and a compound for compounding, the chemical formula of the compound is one or more selected from Cu 2 GeSe 3 、Ag 8 GeTe 6 、Ag 5 Te 3 , and the use amount of the compound is 0.04% -0.1% of the mass of the P-type bismuth telluride matrix. The P-type bismuth telluride-based composite material provided by the invention is characterized in that crystal boundary, second phase and other defects are introduced after the composite to enhance phonon scattering, so that the lattice heat conductivity is effectively reduced, and finally, the improvement of the material performance is realized by utilizing the optimization of the carrier concentration and the reduction of the lattice heat conductivity.

Inventors

  • LIU FENG
  • WU YONGQING
  • TANG ZEFENG
  • LI MING
  • CUI BORAN

Assignees

  • 浙江先导热电科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251225

Claims (10)

  1. 1. The composite P-type bismuth telluride base material is characterized by comprising a P-type bismuth telluride base body, wherein the chemical formula of the P-type bismuth telluride base body is Bi 0.5 Sb 1.5 Te 3.2 , and a compound used for compounding, and the use amount of the compound is 0.04% -0.1% of the mass of the P-type bismuth telluride base body.
  2. 2. The composite P-type bismuth telluride-based material according to claim 1, wherein the chemical formula of the composite compound is selected from one or more of Cu 2 GeSe 3 、Ag 8 GeTe 6 、Ag 5 Te 3 .
  3. 3. A method of preparation as claimed in claim 1 or 2, comprising the steps of: (1) Respectively weighing raw materials according to the chemical formula of the compound, loading the raw materials into a quartz tube, and vacuum sealing the tube; (2) Carrying out high-temperature smelting and annealing on a quartz tube, cooling to obtain a compound, and carrying out ball milling under inert gas to obtain compound powder; (3) Weighing Bi, sb and Te simple substances according to a chemical formula Bi 0.5 Sb 1.5 Te 3.2 of a matrix, filling the simple substances and the compound powder into a quartz tube, and vacuum sealing the tube; (4) Heating and smelting in a swinging furnace, and cooling to obtain an ingot; (5) Crushing the cast ingot under the protection of inert gas to prepare powder, and filling the powder into a metal mold; (6) And (5) putting the die into a hot-pressing furnace, vacuumizing, performing hot-pressing and burning, and cooling to obtain the P-type bismuth telluride-based composite.
  4. 4. The method for preparing a composite P-type bismuth telluride-based material according to claim 3, wherein in the step (1), the compound of the chemical formula Cu 2 GeSe 3 is used for respectively weighing the simple substance raw materials of Cu, ge and Se, the chemical formula Ag 5 Te 3 is used for respectively weighing the simple substance raw materials of Ag and Te, and the chemical formula Ag 8 GeTe 6 is used for respectively weighing the raw materials of Ag 2 Te, geTe, te.
  5. 5. The method for preparing a composite P-type bismuth telluride-based material according to claim 3, wherein the smelting temperature in the step (2) is 850-1050 ℃, the annealing temperature is 420-700 ℃ and the annealing time is 48-96h.
  6. 6. The method for preparing a composite P-type bismuth telluride based material according to claim 5, wherein the melting temperature of Cu 2 GeSe 3 is 900-950 ℃, the annealing temperature is 500-550 ℃, the annealing time is 72-96h, the melting temperature of ag 5 Te 3 is 850-900 ℃, the annealing temperature is 420-500 ℃, the annealing time is 72-96h, the melting temperature of ag 8 GeTe 6 is 970-1050 ℃, the annealing temperature is 620-700 ℃, and the annealing time is 48-72h.
  7. 7. The method for preparing the composite P-type bismuth telluride-based material according to claim 3, wherein the ball milling rotating speed in the step (2) is 400-600r/min, and the ball milling time is 30-50min.
  8. 8. The method for producing a composite P-type bismuth telluride-based material according to claim 3, wherein the powder particle size in the step (2) is <20 μm.
  9. 9. The method for producing a composite P-type bismuth telluride-based material according to claim 3, wherein the melting temperature in the step (4) is 800-1000 ℃.
  10. 10. The method for preparing a composite P-type bismuth telluride-based material according to claim 3, wherein the hot pressing temperature in the step (6) is 450-480 ℃, the pressure is 50-80MPa, and the sintering time is 30-60min.

Description

Composite P-type bismuth telluride base material and preparation method thereof Technical Field The invention belongs to the technical field of thermoelectric materials, and particularly relates to a composite P-type bismuth telluride-based material and a preparation method thereof. Background The p-type bismuth telluride (Bi 2Te3) base material is one of the most mature thermoelectric materials in current commercial use, has good thermoelectric performance and is mainly used for thermoelectric power generation and refrigeration. The p-type material has the advantages of higher seebeck coefficient and electric conductivity, and lower heat conductivity, so that the p-type material is excellent in thermoelectric generation. The thermoelectric material can realize the mutual conversion of heat energy and electric energy by utilizing the Seebeck effect and the Peltier effect, and the thermoelectric device prepared by the method has the advantages of no pollution, no noise, compact structure, no moving parts, no maintenance and the like, and has irreplaceable functions in the fields of deep space exploration power supply, accurate temperature control, high-efficiency refrigeration and the like. The performance evaluation index of the thermoelectric material is that the higher the dimensionless thermoelectric figure of merit zT, the better the thermoelectric performance of the material. The formula is zt=s 2σ/(κL+κe), where S is the seebeck coefficient, σ is the electrical conductivity, κ L is the lattice thermal conductivity, and κ e is the electron thermal conductivity. S, σ, and κ e are closely related to the carrier concentration n of the material, and the presence of an optimal carrier concentration n opt maximizes the zT value. In addition, reducing the kappa L of the material is also an optimization strategy that effectively increases the zT value. Bismuth telluride base alloy is the thermoelectric material with the best performance in the room temperature area at present, and the regulation and control on carrier concentration and lattice thermal conductivity can be realized by compounding other compounds. For example, CN102339946B discloses a high-performance thermoelectric composite material and a preparation method thereof, the composite material of the invention is composed of two phases, the first phase is n-type Bi 2Te3-Bi2Se3 or p-type Bi 2Te3-Sb2Te3, the second phase is metal oxide nano powder, and the metal oxide nano powder accounts for 0.05% -10% of the total weight of the thermoelectric composite material. And carrying out ultrasonic mixing on the n-type Bi 2Te3-Bi2Se3 or the p-type Bi 2Te3-Sb2Te3, carrying out spark plasma sintering on the powder and the nano oxide to obtain the compact bulk material. The invention improves the material performance through composite alumina, titanium oxide and the like. Compared with bismuth telluride-based thermoelectric matrix materials, the material has the advantages that the lattice heat conductivity of the material can be obviously reduced and the Seeback coefficient of the material can be improved under the condition that the electric conductivity of the matrix thermoelectric material is kept unchanged basically, so that the thermoelectric performance of the material can be greatly improved. However, when the metal nano phase with relatively good conductivity is used as the second phase, the chemical stability of the matrix material may be affected due to poor thermal stability of the metal, and these problems limit further improvement of the thermoelectric performance of the material. However, the choice of which compound to complex and the choice of the amount of complex is closely related to the material preparation process, so that the preference of complex compounds based on a specific preparation process is one of the important research matters for optimizing the material properties. Disclosure of Invention In order to improve the thermoelectric performance of the thermoelectric material, the invention provides a composite P-type bismuth telluride-based material and a preparation method thereof, and the P-type bismuth telluride-based composite material is provided, and defects such as crystal boundary, second phase and the like are introduced after the composite to enhance phonon scattering, so that the lattice thermal conductivity is effectively reduced, and finally the improvement of the material performance is realized by utilizing the optimization of the carrier concentration and the reduction of the lattice thermal conductivity. The invention is realized by the following technical scheme: A composite P-type bismuth telluride based material comprises a P-type bismuth telluride matrix with a chemical formula of Bi 0.5Sb1.5Te3.2, And the compound used for compounding, wherein the use amount of the compound is 0.04% -0.1% of the mass of the P-type bismuth telluride matrix. Preferably, the chemical formula of the compound is selected from one or