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CN-121974304-A - P-type Pavonite thermoelectric material with low thermal conductivity and preparation method and application thereof

CN121974304ACN 121974304 ACN121974304 ACN 121974304ACN-121974304-A

Abstract

The invention discloses a p-type Pavonite thermoelectric material with low thermal conductivity, which has a chemical formula of MnSnSb 4 Se 8 , is optimized by Sb vacancy regulation and has a chemical formula of MnSnSb 3.98 Se 8 , the crystal structure of the p-type Pavonite thermoelectric material with low thermal conductivity is composed of a NaCl configuration layer with adjustable thickness and a GeS configuration layer with non-adjustable thickness, the NaCl configuration layer and the GeS configuration layer are connected through shared Se atoms, octahedron common edges formed by [ Sn/MnSe 6 ] and [ SbSe 6 ] in the NaCl configuration layer, the GeS configuration layer is composed of two [ SbSe 5 ] square cones and two [ Sn/MnSe 6 ] octahedrons, the method is simple to operate, a large amount of MnSnSb 4 Se 8 with higher phase purity can be obtained in a short time, the thermoelectric value can reach 0.23 under 823K, and the thermoelectric value can be improved by MnSnSb 3.98 Se 8 to 0.39% under 823K under the condition of 0.02 by Sb vacancy regulation and the thermoelectric value can be improved by 0.39%.

Inventors

  • LUO ZHONGJIAN
  • YANG CHAO
  • WANG SIRU
  • ZHENG YUNPENG
  • CUI HONGHUA
  • ZOU ZHIGANG

Assignees

  • 福州大学

Dates

Publication Date
20260505
Application Date
20260126

Claims (7)

  1. 1. The p-type Pavonite thermoelectric material with low heat conductivity is characterized in that the p-type Pavonite thermoelectric material with low heat conductivity is MnSnSb 4 Se 8 in chemical formula, the chemical formula of the p-type Pavonite thermoelectric material is MnSnSb 3.98 Se 8 after being regulated and optimized through Sb vacancies, the crystal structure of the p-type Pavonite thermoelectric material with low heat conductivity is composed of a NaCl structural layer with adjustable thickness and a GeS structural layer with non-adjustable thickness, the NaCl structural layer and the GeS structural layer are connected through sharing Se atoms, octahedron co-edges of [ Sn/MnSe 6 ] and [ SbSe 6 ] in the NaCl structural layer are connected, and the GeS structural layer is composed of two [ SbSe 5 ] square cones and two [ Sn/MnSe 6 ] octahedrons.
  2. 2. The p-type Pavonite thermoelectric material with low thermal conductivity according to claim 1, wherein the number of diagonal octahedra in said NaCl-structured layer is 3.
  3. 3. The p-type Pavonite thermoelectric material with low thermal conductivity according to claim 1, wherein the crystal structure of the p-type Pavonite thermoelectric material with low thermal conductivity belongs to a monoclinic structure and is of a space group C2/m, and the unit cell parameter of the p-type Pavonite thermoelectric material with low thermal conductivity is a= 13.298 a, b= 4.0135 a, c= 15.0436 a, α=γ=90°, β= 114.906 °, z=2, unit cell volume V= 728.23 a 3 , and theoretical density ρ cal =5.892 g/cm 3 of the crystal.
  4. 4. A method of preparing a p-type Pavonite thermoelectric material having a low thermal conductivity according to any one of claims 1 to 3, comprising the steps of: S1, preparing raw materials, namely preparing simple substance raw materials such as Mn sheets, sn particles, sb blocks and Se particles; S2, mixing raw materials and sealing a pipe in vacuum: When preparing micron-sized single crystals, weighing and uniformly mixing the raw materials according to the molar ratio of Mn to Sn to Sb to Se=11 to 8 to 6 to 32, wherein the total amount is 0.5g, putting the mixed raw materials into a quartz tube with the inner diameter of 10 mm and attached with a carbon film, vacuumizing until the air pressure is less than 10 -3 Pa, and sealing the quartz tube by an oxyhydrogen flame gun; Weighing raw materials according to the molar ratio of Mn to Sn to Se=1:1:4:8 or 1:1:3.98:8, uniformly mixing the raw materials to obtain 6g total, placing the mixed raw materials into a quartz tube with 13mm inner diameter and attached with a carbon film, vacuumizing to the air pressure of less than 10 -3 Pa, and sealing the quartz tube by an oxyhydrogen flame gun; s3, high-temperature reaction: Placing the sealed quartz tube into a box-type muffle furnace, raising the temperature from room temperature to 900 ℃ for 1440min, preserving the temperature at 900 ℃ for 2880min, and slowly cooling to room temperature for 2880min to obtain a single crystal sample; Vacuum smelting reaction of polycrystalline ingot, namely placing the sealed quartz tube into a box-type muffle furnace, heating to 950 ℃ from room temperature for 20 hours, preserving heat for 20 hours at 950 ℃, and rapidly cooling by water quenching to obtain MnSnSb 4 Se 8 or MnSnSb 3.98 Se 8 ingot; s4, post-treatment, namely selecting the single crystal sample obtained in the step S3 under an optical microscope to obtain micron-sized single crystals, grinding the polycrystalline ingot obtained in the step S3 into powder in an agate mortar, and then sintering by discharge plasma to obtain the bulk material with the density of more than 95%.
  5. 5. The method of claim 4, wherein the purity of Mn, sn, sb and Se in the step S1 is greater than 99%.
  6. 6. The method of manufacturing p-type Pavonite thermoelectric material having low thermal conductivity according to claim 4, wherein in step S4, the firing of the discharge plasma is performed by raising the temperature from room temperature to 500 ℃ for 5min, raising the temperature from 500 ℃ to 550 ℃ for 2min, maintaining the temperature at 550 ℃ for 5min, cooling to room temperature in vacuum, and maintaining the axial pressure at 40MPa during the firing.
  7. 7. The p-type Pavonite thermoelectric material with low thermal conductivity according to claim 1-3, wherein the p-type Pavonite thermoelectric material with low thermal conductivity is applied to the clean energy field and used for waste heat recovery power generation.

Description

P-type Pavonite thermoelectric material with low thermal conductivity and preparation method and application thereof Technical Field The invention belongs to the technical field of novel thermoelectric materials, and particularly relates to a p-type Pavonite thermoelectric material with low thermal conductivity, and a preparation method and application thereof. Background The global challenge of energy structure transformation and low-carbon development is currently being faced, and the massive consumption of traditional fossil energy not only aggravates the exhaustion of resources, but also causes serious greenhouse gas emission and environmental pollution. Meanwhile, the energy utilization efficiency has a huge improvement space, about two thirds of energy sources in the world are dissipated in the form of waste heat in the conversion and use processes, such as waste heat in industrial production, automobile exhaust waste heat and the like, and serious energy waste is caused. The thermoelectric technology can directly convert heat energy (including various waste heat) into clean electric energy, and has the remarkable advantages of no moving parts, quiet and reliable operation, long service life and the like. The thermoelectric material can effectively improve the comprehensive utilization efficiency of energy sources by recycling widely-existing low-grade waste heat, reduce the dependence on fossil energy sources, reduce carbon emission from sources, provide an important technical path for constructing a green circulating energy system, and have a key role in sustainable development in the fields of industry, traffic and the like. Therefore, development of novel high-performance thermoelectric materials free of harmful components is one of the important research points in the current thermoelectric field. The Pavonite crystal structure is a three-dimensional structure, is formed by connecting a NaCl configuration layer with adjustable thickness and a GeS configuration layer with non-adjustable thickness through shared anions, has higher structural stability and lower heat conductivity, and shows good development prospect in the thermoelectric field. However, the number of Pavonite crystal structure materials currently available in the thermoelectric field is limited, wherein the p-type Pavonite materials are more scarce, and the large-scale application of Pavonite series materials in the thermoelectric field is severely limited. Therefore, the development of more high-performance p-type thermoelectric materials with Pavonite crystal structures has important practical significance and application value. Disclosure of Invention In order to solve the problems, the invention provides a p-type Pavonite thermoelectric material with low thermal conductivity, and a preparation method and application thereof. In order to achieve the above purpose, the present invention adopts the following technical scheme: The p-type Pavonite thermoelectric material with low heat conductivity has a chemical formula of MnSnSb 4Se8, a chemical formula of MnSnSb 3.98Se8 after being optimized through Sb vacancy regulation, a crystal structure of the p-type Pavonite thermoelectric material with low heat conductivity is composed of a NaCl configuration layer with adjustable thickness and a GeS configuration layer with non-adjustable thickness, the NaCl configuration layer and the GeS configuration layer are connected through sharing Se atoms, octahedral co-edges formed by [ Sn/MnSe 6 ] and [ SbSe 6 ] in the NaCl configuration layer, and the GeS configuration layer is composed of two [ SbSe 5 ] tetragonal cones and two [ Sn/MnSe 6 ] octahedrons. Preferably, the number of diagonal octahedra in the NaCl structured layer is 3. Preferably, the crystal structure of the p-type Pavonite thermoelectric material with low thermal conductivity belongs to a monoclinic structure and a space group C2/m, and the unit cell parameter of the p-type Pavonite thermoelectric material with low thermal conductivity is a= 13.298 a, b= 4.0135 a, c= 15.0436 a, α=γ=90°, β= 114.906 °, z=2, unit cell volume V= 728.23 a 3, and theoretical density ρ cal=5.892 g/cm3 of the crystal. A method for preparing p-type Pavonite thermoelectric material with low thermal conductivity, comprising the following steps: S1, preparing raw materials, namely preparing simple substance raw materials such as Mn sheets, sn particles, sb blocks and Se particles; S2, mixing raw materials and sealing a pipe in vacuum: When preparing micron-sized single crystals, weighing and uniformly mixing the raw materials according to the molar ratio of Mn to Sn to Sb to Se=11 to 8 to 6 to 32, wherein the total amount is 0.5g, putting the mixed raw materials into a quartz tube with the inner diameter of 10 mm and attached with a carbon film, vacuumizing until the air pressure is less than 10 -3 Pa, and sealing the quartz tube by an oxyhydrogen flame gun; Weighing raw materials according to the molar ra