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CN-121974307-A - Method for preparing SnX micron thermoelectric material by hydrothermal method and application thereof

CN121974307ACN 121974307 ACN121974307 ACN 121974307ACN-121974307-A

Abstract

The invention discloses a method for preparing SnX micrometer thermoelectric material by a hydrothermal method and application thereof, wherein the method comprises the following steps of (1) adding an X source into sodium borohydride solution under the condition of inert atmosphere to react to obtain an anion precursor, wherein X is Se or Te, (2) adding sodium hydroxide and a tin source into the anion precursor, stirring and mixing uniformly, performing hydrothermal reaction, cooling, centrifugally washing and drying to obtain SnX micrometer crystals, namely the SnX micrometer thermoelectric material. The method has the advantages of mild reaction conditions, simple process flow, low energy consumption, controllable cost, good repeatability and higher yield, and is suitable for realizing the rapid and large-scale preparation of the SnX micrometer material. The prepared material can be further processed into a block thermoelectric material, has good electrical property, and is suitable for preparing SnX-based micron thermoelectric materials and related applications.

Inventors

  • LIU YU
  • LU SHAOQING
  • WANG CHENXIN
  • WAN SHANHONG

Assignees

  • 合肥工业大学

Dates

Publication Date
20260505
Application Date
20260203

Claims (10)

  1. 1. The method for preparing the SnX micron thermoelectric material by the hydrothermal method is characterized by comprising the following steps of: (1) Under the inert atmosphere condition, adding an X source into a sodium borohydride solution to react to obtain an anion precursor, wherein X is Se or Te; (2) Adding sodium hydroxide and a tin source into the anion precursor, stirring and mixing uniformly, performing hydrothermal reaction, and then cooling, centrifugally washing and drying to obtain SnX micron crystals, namely the SnX micron thermoelectric material.
  2. 2. The method for preparing SnX micrometer thermoelectric materials by using a hydrothermal method according to claim 1, wherein in the step (1), the X source is Se powder or Te powder, and the solvent for the reaction is deionized water.
  3. 3. The method for preparing SnX micrometer thermoelectric materials by using a hydrothermal method according to claim 1, wherein in the step (1), the molar ratio of the X source to sodium borohydride is 1:2-3, and the reaction time is 1-2 h.
  4. 4. The method of preparing SnX micrometer thermoelectric materials according to claim 1, wherein in the step (2), the molar ratio of the tin source to the X source is 1:1-2:1, the concentration of sodium hydroxide is 1.5-2 mol/L, and the stirring time is 5-10 min.
  5. 5. The method of claim 1, wherein in the step (2), the tin source is a soluble tin salt.
  6. 6. The method for preparing SnX micrometer thermoelectric materials by using a hydrothermal method according to claim 1, wherein in the step (2), the temperature of the hydrothermal reaction is 160-200 ℃, and the time of the hydrothermal reaction is 12-24 h.
  7. 7. The method for preparing the SnX micrometer thermoelectric material by using the hydrothermal method according to claim 1, wherein in the step (2), the centrifugal washing is performed by using absolute ethyl alcohol and deionized water, the centrifugal rotation speed is 6000-9000 rpm and 5-10 min each time, the drying mode is vacuum drying, the drying temperature is 60-80 ℃, and the drying time is 3-8 h.
  8. 8. A preparation method of the SnX thermoelectric material block is characterized by comprising the steps of carrying out annealing treatment on the SnX micrometer thermoelectric material prepared by the method of any one of claims 1-7 to obtain SnX thermoelectric material powder, and then carrying out densification treatment to obtain the SnX thermoelectric material block, wherein the densification treatment is hot press sintering.
  9. 9. The preparation method of the SnX thermoelectric material block according to claim 8, wherein when X is Te, the annealing treatment temperature is 600 ℃, the heating time is 1-1.5H, the heat preservation is 2-3H, when X is Se, the annealing temperature is 500 ℃, the heating time is 50-60 min, the heat preservation is 2-3H, and the volume fraction of Ar and H 2 used for annealing is 95%.
  10. 10. The method of producing a block of SnX thermoelectric material according to claim 9, wherein the sintering temperature of the hot press sintering is 450-500 ℃, the sintering pressure is 48-50 MPa, and the holding time is 8-10 min.

Description

Method for preparing SnX micron thermoelectric material by hydrothermal method and application thereof Technical Field The invention relates to the technical field of energy materials, in particular to a method for preparing SnX micron thermoelectric materials by a hydrothermal method and application thereof. Background Under the background of continuous increase of global energy demand and increasingly prominent environmental problems, the improvement of energy utilization efficiency and the development of clean energy technology have become important research directions. The thermoelectric material can realize direct conversion of heat energy and electric energy, and has wide application prospect in the fields of waste heat recovery, solid refrigeration, energy management and the like. The performance of thermoelectric materials is generally characterized by a thermoelectric figure of merit zT, where zT = σs2t/κ, σ is the electrical conductivity, S is the seebeck coefficient, κ is the thermal conductivity, and T is the absolute temperature. Development of thermoelectric materials with higher zT values in the near-to-mid temperature range is one of the important research targets in the current thermoelectric field. SnTe and SnSe are used as typical thermoelectric materials of IV-VI groups of compounds, and have good application potential in a medium temperature region. Among them, snTe has a NaCl cubic rock salt structure, and generally exhibits higher carrier concentration and σ due to higher intrinsic Sn vacancy concentration, but S is relatively low, limiting further improvement of thermoelectric performance thereof. SnSe has an obvious anisotropic crystal structure and a strong phonon non-simple harmonic effect, and shows lower lattice thermal conductivity (kappa L) and larger thermoelectric regulation space. In recent years, the optimization of the thermoelectric performance of SnTe and SnSe-based materials by energy band structure regulation has been advanced, but the optimization of electric transport and thermal transport synergy is still more challenging in terms of high sigma and S and realization of the synergistic optimization of electric transport and thermal transport. The preparation of the existing SnX (X is Se or Te) material mainly depends on a solid-phase reaction method or a high-temperature melting method, wherein the vacuum melting method is widely applied. Such methods typically require long-term reactions above the melting point of the material, and strict control of the rate of rise and fall temperatures and atmospheric conditions to avoid equipment damage or component segregation. In order to obtain the SnX material with uniform components and pure phases, annealing treatment is often required to be carried out for a plurality of days, so that the preparation period is long, the energy consumption is high, and the process is complex. In addition, the high-temperature preparation method has certain limitations in scale-up, batch stability and accurate regulation and control of doping elements, and is difficult to meet the actual requirements of scale preparation and performance regulation and control of the SnX thermoelectric material. Therefore, a new method for preparing the SnX material under relatively mild conditions is needed to be provided, and the method has the characteristics of simple process flow, controllable reaction conditions, good repeatability, easy scale implementation and the like, so that a reliable technical approach is provided for improving the performance of the SnTe and SnSe-based thermoelectric materials and engineering application thereof. Disclosure of Invention The invention aims to provide a method for preparing an SnX micrometer thermoelectric material by a hydrothermal method and application thereof, so as to solve the problems of harsh reaction conditions, high energy consumption, long preparation period, difficulty in realizing large-scale preparation and the like in the preparation process of the existing SnX (X is Se or Te) material, realize controllable synthesis of the SnX micrometer thermoelectric material under relatively mild conditions, and provide a reliable material foundation for subsequent thermoelectric performance regulation and engineering application. In one aspect of the invention, the invention provides a method for preparing an SnX micron thermoelectric material by a hydrothermal method. According to an embodiment of the invention, the method comprises the steps of: (1) Under the inert atmosphere condition, adding an X source into a sodium borohydride solution to react to obtain an anion precursor, wherein X is Se or Te; (2) Adding sodium hydroxide and a tin source into the anion precursor, stirring and mixing uniformly, performing hydrothermal reaction, and then cooling, centrifugally washing and drying to obtain SnX micron crystals, namely the SnX micron thermoelectric material. In addition, the method for preparing the SnX mi