Preparation method capable of improving thermoelectric properties of tin(II) selenide-based material via combination of composition regulation and mesoscopically ordered regulation

Abstract

The present invention relates to a preparation method capable of improving thermoelectric properties of a tin(II) selenide-based material via combination of composition regulation and mesoscopically ordered regulation, belonging to the technical field of the preparation of high-performance thermoelectric materials. The molecular formula of the tin(II) selenide-based material of the present invention is Sn(1-x)Se(0.93-6x)(WCl6)x. Raw materials thereof comprise tin granules, selenium granules and tungsten hexachloride powder. The preparation method comprises: weighing raw materials in a glovebox according to the atomic mass ratio; using a double-layer quartz tube, vacuumizing same, and putting the raw materials into a muffle furnace to melt and react same; then milling an obtained ingot by using a mortar in the glovebox to obtain a composition-regulated Sn(1-x)Se(0.93-6x)(WCl6)x powder; then performing spark plasma sintering on the Sn(1-x)Se(0.93-6x)(WCl6)x powder by successively using graphite molds having different inner diameters, so as to induce and arrange the orientation of grain growth, so that the tin(II) selenide-based thermoelectric material can grow under mesoscopically ordered regulation, thereby improving electrical, thermal and mechanical properties. The tin(II) selenide-based thermoelectric material prepared via composition regulation and mesoscopically ordered regulation has effectively improved electrical, thermal and mechanical properties.

Description

A preparation method for improving the thermoelectric performance of tin selenide-based materials by composition regulation combined with mesoscopic order regulation TECHNICAL FIELD

[0001] The present application relates to the field of thermoelectric material preparation, in particular to a preparation method for improving the thermoelectric performance of tin selenide-based materials by composition regulation combined with mesoscopic order regulation. BACKGROUND

[0002] Thermoelectric materials can realize the direct mutual conversion between heat and electricity. Thermoelectric devices have the advantages of long service life, small size, no noise during operation, fast response speed, high temperature control precision, low maintenance cost, environmental friendliness, etc. They have potential applications in the fields of high-end all-solid-state thermal management such as 5G optical communication chips and deep space exploration power supply. The rapid development of microelectronic technology has led to an exponential increase in the power density of electronic devices, posing unprecedented challenges to intelligent temperature control technology. Therefore, thermoelectric materials need to be further improved in mechanical properties, especially those with special layered structure such as tin selenide, while maintaining excellent thermoelectric performance. Bi2Te3 is also a layered thermoelectric material suitable for room temperature, but the Te element in it is highly toxic and expensive. Tin selenide-based thermoelectric materials have abundant earth crust content, low price, environmental friendliness and low preparation cost, making them a new type of thermoelectric material.

[0003] In view of the problem of low electrical transport performance caused by a large number of intrinsic defects in tin selenide, it is found that changing the chemical composition to regulate the defect concentration, filling intrinsic defects with external elements of different valence, and inducing grain growth direction to obtain ordered regulation growth are feasible optimization strategies. SUMMARY

[0004] In order to overcome the problem that existing thermoelectric materials cannot achieve simultaneous optimization of electrical, thermal and mechanical properties, the present application provides a preparation method for improving the thermoelectric performance of tin selenide by composition regulation combined with mesoscopic order regulation. By regulating the composition of tin selenide with WCl6, the electrical conductivity is effectively improved, and at the same time, W and Cl can occupy the positions of Sn and Se to form zero-dimensional defects, so that the thermal conductivity is optimized at a relatively high temperature. Then, different size graphite molds are used for mesoscopic order regulation, so that the tin selenide can maintain high electrical transport performance while the thermal transport performance and mechanical properties are further optimized.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The first aspect of the present application provides a preparation method for improving the thermoelectric performance of tin selenide-based materials by composition regulation combined with mesoscopic order regulation, comprising the following steps:

[0007] (1) In a glove box, tin source, selenium source and tungsten hexachloride are weighed according to the atomic mass ratio, and are placed in a double-layer quartz tube for vacuumizing and packaging;

[0008] (2) The double-layer quartz tube is placed in a muffle furnace for melting reaction, and after the melting is completed, the furnace is cooled to room temperature, and a cast ingot is obtained;

[0009] (3) The cast ingot is ground into powder, and is subjected to discharge plasma sintering using graphite molds of different sizes, and a tin selenide-based thermoelectric material is obtained.

[0010] Principles and beneficial effects of the application: Through the melting reaction, the Sn and Se components in the matrix can be changed, and W and Cl partially occupy the Sn and Se positions, so that the carrier concentration is improved in the entire test temperature range, thereby improving the electrical conductivity. At the same time, after W and Cl regulate the tin selenide composition, the energy band structure of the matrix is aligned, so that the electron effective mass is improved, thereby optimizing the Seebeck coefficient. In addition, W and Cl occupy the Sn and Se regions to form zero-dimensional defects, and the remaining W and Cl exist in the matrix in the form of nano precipitates, which effectively scatters phonons, thereby optimizing the thermal conductivity. Finally, the growth direction of the tin selenide grains is induced at the mesoscale, and the grains are ordered to grow, so that the matrix maintains a high level of electrical transport performance, and the thermal transport performance and mechanical performance are further optimized.

[0011] The raw materials are weighed in a glove box to effectively prevent the possibility of oxidation of the raw materials. In addition, the double-layer quartz tube is vacuumized and melted, which can prevent the oxidation of the raw materials during the reaction and prevent the oxidation of the raw materials caused by the explosion of the single-layer quartz tube. The prepared tin selenide is more economical and environmentally friendly than Bi2Te3.

[0012] Preferably, the molecular formula of the tin selenide-based thermoelectric material is Sn (1-x) Se (0.93-6x) (WCl6) x , wherein 0.0025≤x≤0.02. In some specific embodiments of the application, the value of x can be 0.0025, 0.005, 0.01 and 0.02.

[0013] Preferably, in step (1), the vacuum degree of the vacuumizing is ≤10 -4 Pa. The raw materials are completely isolated from air to avoid the interference of oxygen and moisture in the air on the sample, and then packaged to maintain a high vacuum environment.

[0014] Preferably, in step (2), the temperature of the melting reaction is 900-1000℃, and the time is 22-26h; further preferably, in step (2), the temperature of the melting reaction is 940-960℃, and the time is 23-25h. If the melting temperature is too low, the reaction of the components will not be sufficient, and if the melting temperature is too high, the double-layered quartz tube may be broken, and the temperature that is too high will also cause some raw materials to volatilize to the inner wall of the quartz tube and not to fall off, resulting in an increase in the composition error. The temperature and time of the present application can make the mixed liquid after melting fully fused, and eliminate defects to reduce errors.

[0015] Preferably, in step (3), the ingot is ground in a mortar in a glove box for 25-35min; further preferably, the ingot is ground in a mortar in a glove box for 30min, which can effectively prevent the sample from being disturbed by oxygen and moisture in the air during the crushing process.

[0016] Preferably, in step (4), the number of times of the spark plasma sintering is ≥2.

[0017] Further preferably, in step (4), when the number of times of the spark plasma sintering is ≥2, the inner diameter of the graphite mold used in the last time of spark plasma sintering is larger than that of the graphite mold used in the previous time of sintering. Using different inner diameters for multiple sintering can induce the growth direction of tin selenide grains, so that the grains obtain ordered and regulated growth.

[0018] Further preferably, in step (4), the number of times of the spark plasma sintering is 2-4.

[0019] In some embodiments of the present application, the inner diameter of the graphite mold used for spark plasma sintering is 12.7mm, 15mm, 20mm and 25mm; the graphite mold size used for the first time of spark plasma sintering is 12.7mm, the obtained ingot is polished, and the second time of sintering is performed using a 15mm graphite mold; the obtained ingot is polished, and the third time of sintering is performed using a 20mm graphite mold; the obtained ingot is polished again, and the fourth time of sintering is performed using a 25mm graphite mold.

[0020] Preferably, in step (4), the temperature of the spark plasma sintering is 480-520℃, the pressure is 48-52MPa, and the time is 8-12min; further preferably, in step (4), the temperature of the spark plasma sintering is 500℃, the pressure is 50MPa, and the time is 10min.

[0021] The second aspect of the present application provides a tin selenide-based thermoelectric material prepared by the preparation method for improving the thermoelectric performance of tin selenide-based materials by combining composition regulation with mesoscopic order regulation.

[0022] Compared with the prior art, the application has the beneficial effects of:

[0023] 1. The selenium tin-based thermoelectric material regulated by WCl6 component, part of W and Cl occupies Sn and Se position, the carrier concentration is effectively improved in the whole test temperature range. At the same time, the energy band alignment is promoted, the effective mass is improved, and the Seebeck coefficient is further optimized. Finally, the maximum power factor reaches 565 μW m -1 K -2 .

[0024] 2. Part of W and Cl occupies Sn and Se position, forms zero-dimensional defects, and the rest of W and Cl exists in the matrix in the form of nano precipitates, which effectively scatters phonons. Finally, the minimum thermal conductivity reaches 0.29 W m -1 K -1 .

[0025] 3. By using different inner diameter graphite molds for spark plasma sintering, the selenium tin grains are obtained by ordered regulation growth, and the layered structure is obvious at the mesoscale, which makes the electrical transport performance maintain a high level (the maximum power factor is maintained at 552.7 μW m -1 K -2 ) while the thermal conductivity is further optimized. The minimum thermal conductivity reaches 0.24 W m -1 K -1 at 823 K, the maximum ZT value reaches 1.9, and the hardness is improved from 0.87 GPa to 1.5 GPa. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a thermoelectric performance diagram of the selenium tin thermoelectric material prepared in Example 1 and Comparative Examples 1, 2, 3 and 4;

[0027] Figure 2 is an electronic structure diagram of the selenium tin thermoelectric material prepared in Example 1;

[0028] Figure 3 is a scanning electron microscope diagram of the selenium tin thermoelectric material prepared in Example 3;

[0029] Figure 4 is a comparison diagram of the thermoelectric performance of the selenium tin thermoelectric materials prepared in Example 1, Example 2 and Example 3;

[0030] Figure 5 is a nano indentation test diagram of the selenium tin thermoelectric materials prepared in Example 1, 2, 3 and Comparative Example 1. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application are described further below. It should be noted that the description of these embodiments is intended for the purpose of aiding in the understanding of the present application and is in no way intended to limit the present application. Furthermore, the technical features involved in each of the embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0032] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0033] Example 1

[0034] A tin selenide-based thermoelectric material with component regulation and performance improvement, with a general chemical formula of Sn (1-x) Se (0.93-6x) (WCl6) x , x is 0.01, i.e. Sn 0.99 Se 0.87 (WCl6) 0.01 , is prepared by the following method:

[0035] In a glove box, 4.9436 g of tin particles with a purity of greater than 99.99%, 2.8896 g of selenium particles with a purity of greater than 99.999%, and 0.1668 g of WCl6 powder with a purity of greater than 99.9% are weighed and placed in a double-layer quartz tube for vacuumizing. A molecular pump is used for vacuumizing for 20 minutes, and when the vacuum degree reaches 10 -4 Pa, the double-layer quartz tube containing the raw materials is sealed and placed in a muffle furnace for melting reaction. The temperature is raised to 950℃ at a rate of 95℃ / h, and the reaction is allowed to proceed at this temperature for 24 h. After the reaction is completed, the temperature is lowered to room temperature at a rate of 95℃ / h. The obtained ingot is ground in a mortar for 30 minutes in a glove box, and the obtained powder is sintered at a temperature of 500℃ and a pressure of 50 MPa using a 12.7 mm inner diameter graphite mold for 10 minutes to obtain a bulk material. -1 -1 The thermoelectric material prepared in this example has the related thermoelectric performance diagram as shown in FIG. 1, and the electronic structure diagram as shown in FIG. 2.

[0036] The thermoelectric material prepared in this example has the related thermoelectric performance diagram as shown in FIG. 1, and the electronic structure diagram as shown in FIG. 2.

[0037] Example 2

[0038] A tin selenide-based thermoelectric material with component regulation and performance improvement, with a general chemical formula of Sn 0.99 Se 0.87 (WCl6) 0.01 The material is subjected to mesoscopic order regulation, and is prepared by the following method:

[0039] ​Weigh out 4.9436g of tin granules with a purity greater than 99.99%, 2.8896g of selenium granules with a purity greater than 99.999%, and 0.1668g of WCl6 powder with a purity greater than 99.9% in a glove box. Place them in a double-walled quartz tube and evacuate the vacuum tube. Use a molecular pump to evacuate the vacuum for 20 minutes until the vacuum level reaches 10. -4 The process involves encapsulation at Pa, placing a double-layered quartz tube containing the raw material under vacuum in a muffle furnace for melting and reaction at 95°C for h. -1 The temperature was increased to 950℃ and maintained at this temperature for 24 hours to allow for a complete reaction. After the reaction was completed, the temperature was increased to 950℃ for another 24 hours. -1 The process was slowed down to room temperature. The obtained ingot was hand-ground in a mortar and pestle for 30 minutes in a glove box. The resulting powder was sintered for 10 minutes at 500℃ and 50MPa using a graphite mold with an inner diameter of 12.7mm to obtain Sn with controlled composition. 0.99 Se 0.87 (WCl6) 0.01 Bulk material. Then, the obtained ingot is polished with sandpaper and sintered for 10 minutes using a graphite mold with an inner diameter of 15 mm at a temperature of 500℃ and a pressure of 50MPa to obtain the bulk material after the first mesoscopic order regulation.

[0040] The thermoelectric properties of the thermoelectric material prepared in this embodiment are shown in Figure 4, and the relevant nanoindentation test results are shown in Figure 5.

[0041] Example 3

[0042] A tin selenide thermoelectric material with improved performance through compositional regulation combined with mesoscopic ordered regulation, using Sn after compositional regulation. 0.99 Se 0.87 (WCl6) 0.01 The material underwent mesoscopic order regulation and was prepared by the following method:

[0043] Weigh out 4.9436g of tin granules with a purity greater than 99.99%, 2.8896g of selenium granules with a purity greater than 99.999%, and 0.1668g of WCl6 powder with a purity greater than 99.9% in a glove box. Place them in a double-walled quartz tube and evacuate the vacuum tube. Use a molecular pump to evacuate the vacuum for 20 minutes until the vacuum level reaches 10. -4 The process involves encapsulation at Pa, placing a double-layered quartz tube containing the raw material under vacuum in a muffle furnace for melting and reaction at 95°C for h. -1 The temperature was increased to 950℃ and maintained at this temperature for 24 hours to allow for a complete reaction. After the reaction was completed, the temperature was increased to 950℃ for another 24 hours. -1 The process was slowed down to room temperature. The obtained ingot was hand-ground in a mortar and pestle for 30 minutes in a glove box. The resulting powder was sintered for 10 minutes at 500℃ and 50MPa using a graphite mold with an inner diameter of 12.7mm to obtain Sn with controlled composition.0.99 Se 0.87 (WCl6) 0.01 Bulk material. Then, the obtained ingot is polished with sandpaper and sintered for 10 minutes at 500℃ and 50MPa using a graphite mold with an inner diameter of 15mm to obtain the bulk material after the first mesoscopic order regulation. Following the above method, the obtained bulk material with the first mesoscopic order regulation is polished with sandpaper and sintered for 10 minutes at 500℃ and 50MPa using a graphite mold with an inner diameter of 20mm to obtain the bulk material after the second mesoscopic order regulation.

[0044] The scanning electron microscope image of the thermoelectric material prepared in this embodiment is shown in Figure 3, the thermoelectric performance diagram is shown in Figure 4, and the relevant nanoindentation test diagram is shown in Figure 5.

[0045] Comparative Example 1

[0046] This embodiment provides a tin selenide thermoelectric material SnSe. 0.93 It is prepared by the following method:

[0047] When x = 0, 6.1779 g of tin granules with a purity greater than 99.99% and 3.8221 g of selenium granules with a purity greater than 99.999% were weighed in a glove box and placed in a double-layered quartz tube for vacuuming. A molecular pump was used to evacuate the vacuum for 20 minutes, until the vacuum degree reached 10. -4 The process involves encapsulation at Pa, placing a double-layered quartz tube containing the raw material under vacuum in a muffle furnace for melting and reaction at 95°C for h. -1 The temperature was increased to 950℃ and maintained at this temperature for 24 hours to allow for a complete reaction. After the reaction was completed, the temperature was increased to 950℃ for another 24 hours. -1 The process was slowed down to room temperature. The obtained ingot was hand-ground in a mortar and pestle for 30 minutes in a glove box. The resulting powder was sintered for 10 minutes at 500℃ and 50MPa using a graphite mold with an inner diameter of 12.7mm to obtain SnSe. 0.93 Bulk materials.

[0048] The difference between Comparative Example 1 and Example 1 is that WCl6 was not added; that is, Comparative Example 1 yielded a pure tin selenide sample. The thermoelectric material SnSe prepared in this comparative example... 0.93 The thermoelectric properties are shown in Figure 1.

[0049] Comparative Example 2

[0050] The difference between Comparative Example 2 and Example 1 is that the Sn prepared in Comparative Example 2... (1-x) Se (0.93-6x) (WCl6) xIngot, where x = 0.0025. When x = 0.0025, in a glove box, tin metal pellets with purity greater than 99.99% 4.9428 g, selenium pellets with purity greater than 99.999% 3.0158 g, and WCl6 powder with purity greater than 99.9% 0.0414 g were weighed. The relevant performance comparison chart is shown in Figure 1.

[0051] Comparative Example 3

[0052] Comparative Example 3 differs from Example 1 in that Sn (1-x) Se (0.93-6x) (WCl6) x Ingot, where x = 0.005. When x = 0.005, in a glove box, tin metal pellets with purity greater than 99.99% 4.9431 g, selenium pellets with purity greater than 99.999% 2.9740 g, and WCl6 powder with purity greater than 99.9% 0.0830 g were weighed. The relevant performance comparison chart is shown in Figure 1.

[0053] Comparative Example 4

[0054] Comparative Example 4 differs from Example 1 in that Sn (1-x) Se (0.93-6x) (WCl6) x Ingot, where x = 0.02. When x = 0.02, in a glove box, tin metal pellets with purity greater than 99.99% 4.9446 g, selenium pellets with purity greater than 99.999% 2.7184 g, and WCl6 powder with purity greater than 99.9% 0.3371 g were weighed. The relevant performance comparison chart is shown in Figure 1.

[0055] Comparative Example 4 0.93 , Sn 0.9975 Se 0.915 (WCl6) 0.0025 , Sn 0.995 Se 0.90 (WCl6) 0.005 , Sn 0.99 Se 0.87 (WCl6) 0.01 and Sn 0.98 Se 0.81 (WCl6) 0.02The conductivity, Seebeck coefficient, power factor, thermal conductivity and ZT value are compared. The relevant thermoelectric performance diagram is shown in Figure 1 (wherein Figure 1a is a conductivity performance diagram, Figure 1b is a Seebeck coefficient performance diagram, Figure 1c is a power factor diagram, Figure 1d is a total thermal conductivity diagram, Figure 1e is a lattice thermal conductivity diagram, and Figure 1f is a thermoelectric figure of merit diagram. The electronic structure diagram of the material prepared in Example 1 is shown in Figure 2 (wherein Figure 2a is a calculated actual electronic structure diagram, and Figure 2b is a corresponding energy band alignment diagram).

[0056] By adjusting the composition of SnSe with WCl6, part of W and Cl occupy the positions of Sn and Se respectively, a large number of electrons are introduced, the carrier concentration is improved, and at the same time, the energy band is aligned, the effective mass of electrons is improved, the conductivity and Seebeck coefficient are improved at the same time. In addition, part of W and Cl occupying the positions of Sn and Se respectively can introduce zero-dimensional defects, and the remaining W and Cl exist in the form of nano precipitates in the matrix, which can effectively scatter phonons, so that the thermal conductivity is optimized, and finally the ZT value reaches 1.48 at 823K. Further, in Examples 2 and 3, by inducing the arrangement of grain growth direction at the mesoscale to obtain ordered regulation growth, the thermoelectric performance is further improved, and the ZT value reaches 1.9 at 823K.

[0057] As shown in Figures 1 to 5, the ingot obtained by the scheme and SnSe 0.93 After the composition regulation by WCl6 and the mesoscopic order regulation, the synergistic improvement of the electrical, thermal and mechanical properties is realized, which shows that the scheme has achieved remarkable beneficial effects.

[0058] Figure 1 is a thermoelectric performance diagram of SnSe thermoelectric material prepared in Example 1 and Comparative Examples 1, 2, 3 and 4. As shown in Figure 1, after the composition regulation by WCl6, part of W and Cl occupy the positions of Sn and Se respectively, a large number of electrons are introduced, the carrier concentration is improved, and the conductivity is directly optimized; part of W and Cl occupying the positions of Sn and Se respectively can introduce zero-dimensional defects, and the remaining W and Cl exist in the form of nano precipitates in the matrix, which can effectively scatter phonons, so that the thermal conductivity is optimized.

[0059] Figure 2 is an electronic structure diagram of SnSe thermoelectric material prepared in Example 1. As shown in Figure 2, after the composition regulation by WCl6, the energy band of the material is aligned, which improves the effective mass of electrons and the Seebeck coefficient.

[0060] Figure 3 is a scanning electron microscope diagram of SnSe thermoelectric material prepared in Example 3, showing the fracture morphology of the bulk sample parallel and perpendicular to the sintering pressure direction. As shown in Figure 3, after the mesoscopic order regulation, the sample can grow in an ordered and regulated manner, and a clear layered structure appears at the mesoscale, which can effectively reduce the thermal conductivity without affecting the electrical transport performance.

[0061] Figure 4 is a comparison chart of the thermoelectric performance of the tin selenide thermoelectric materials prepared in Example 1, Example 2 and Example 3. As shown in Figure 4, the thermoelectric performance is further optimized after the mesoscopic order is controlled.

[0062] Figure 5 is a nanoindentation test chart of the tin selenide thermoelectric materials prepared in Example 1, 2, 3 and Comparative Example 1. As shown in Figure 5, the mechanical performance is obviously improved after the WCl6 component is controlled and the mesoscopic order is controlled.

[0063] The above detailed the embodiments of the present application, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A method for preparing SnSe-based thermoelectric materials with enhanced performance by using composition tuning, binding mesoscopic order tuning, and composition tuning, characterized in that, The method comprises the following steps: (1) taking tin source, selenium source and tungsten hexachloride by atomic mass ratio in a glove box, and placing them in a double-layer quartz tube to perform vacuum extraction and packaging; (2) placing the double-layer quartz tube in a muffle furnace to perform a melting reaction, and cooling to room temperature after the melting is completed to obtain an ingot; (3) grinding the ingot into powder, and performing discharge plasma sintering using graphite molds of different sizes to obtain a tin selenide-based thermoelectric material.

2. The method according to claim 1, wherein the method for preparing SnSe-based thermoelectric material with enhanced performance by modulating the binding mediated by the mesoscopic order with the components is characterized in that, The formula of the Sn-based thermoelectric material is Sn (1-x) Se (0.93-6x) (WCl6) x , wherein 0.0025≤x≤0.

02.

3. The method according to claim 1, wherein the method is characterized by, In step (1), the vacuum degree of the vacuumizing is ≤ 10 -4 Pa.

4. The method for preparing SnSe-based thermoelectric material with improved performance by using composition regulation combined with mesoscopic order regulation according to claim 1, characterized in that, In step (2), the temperature of the melting reaction is 900-1000 DEG C, and the time is 22-26 h.

5. The method for preparing SnSe-based thermoelectric material with enhanced performance by using composition regulation combined with mesoscopic order regulation of claim 1, wherein, In step (3), the ingot is ground in a mortar in the glove box for 25-35 min.

6. The method for preparing SnSe-based thermoelectric material with enhanced performance by using composition regulation combined with mesoscopic order regulation of claim 1, wherein, In step (4), the number of times of discharge plasma sintering is greater than or equal to 2.

7. The method according to claim 6, wherein the method is characterized by, In step (4), when the number of times of discharge plasma sintering is greater than or equal to 2, the inner diameter of the graphite mold used in the last time of discharge plasma sintering is greater than the inner diameter of the graphite mold used in the previous time of sintering.

8. The method according to claim 6, wherein the method is characterized by, In step (4), the number of times of discharge plasma sintering is 2-4.

9. The method for preparing SnSe-based thermoelectric material with enhanced performance by using composition regulation combined with mesoscopic order regulation of claim 1, wherein, In step (4), the temperature of the discharge plasma sintering is 480-520 DEG C, the pressure is 48-52 MPa, and the time is 8-12 min.

10. A tin selenide-based thermoelectric material, characterized by, The tin selenide-based thermoelectric material is prepared by the method for improving the performance of a tin selenide-based thermoelectric material by regulating the combination of components, meso-order regulation and discharge plasma sintering according to any one of claims 1-9.

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