Modified MgAgSb-based thermoelectric material and preparation method and application thereof
By employing a dual-doping strategy of Cu and Bi in MgAgSb-based thermoelectric materials, the electrical and thermal properties were improved, solving the problem of limited performance enhancement of MgAgSb-based thermoelectric materials and achieving efficient thermoelectric conversion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-21
- Publication Date
- 2026-03-10
AI Technical Summary
There are few existing methods for optimizing the performance of MgAgSb-based thermoelectric materials, resulting in limited performance improvements and making it difficult to effectively utilize low-temperature waste heat resources.
By employing a dual-doping strategy of Cu and Bi, Cu dopants Ag sites and Bi dopants Sb sites in MgAgSb-based thermoelectric materials, and the electrical and thermal properties are improved through synergistic effects, thus preparing modified MgAgSb-based thermoelectric materials.
It improves the overall performance of thermoelectric materials, especially the thermoelectric figure of merit (zT value) at near room temperature, and achieves efficient conversion of electrical and thermal energy.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of thermoelectric materials, in particular to a modified MgAgSb-based thermoelectric material and a preparation method and application thereof. BACKGROUND
[0002] In the process of human activities, a large amount of waste heat is generated, which is often wasted without being directly collected. Thermoelectric materials can effectively utilize this part of heat due to their unique thermoelectric conversion effect, which can not only improve the utilization efficiency of traditional fossil fuels, but also help to save resources and protect the environment. In addition, compared with traditional heat engines, thermoelectric devices do not have moving mechanical parts, so they do not require complex maintenance, which makes thermoelectric systems more reliable and stable in long-term operation. There is a part of waste heat with a temperature lower than 373K in waste heat, including automobile exhaust, heat exchangers in various industrial processes, refrigeration machine bodies, hot springs, boilers, human bodies, etc. This part of waste heat has low heat value and is distributed in a scattered manner, which makes it more difficult to be recycled and utilized by traditional technologies, and it needs to be collected by near-room temperature thermoelectric technology.
[0003] The MgAgSb-based thermoelectric material has excellent near-room temperature thermoelectric performance, and the raw materials are more easily obtained and cheaper than the currently commercialized Bi2Te3-based thermoelectric material, so it has good application prospects. However, there are few means to optimize the performance of the MgAgSb-based thermoelectric material at present, and the degree of performance improvement is limited. Therefore, it is urgent to provide a MgAgSb-based thermoelectric material with more excellent performance. SUMMARY
[0004] The present application provides a modified MgAgSb-based thermoelectric material and a preparation method and application thereof. The modified MgAgSb-based thermoelectric material synchronously improves the electrical performance and thermal performance of the MgAgSb-based thermoelectric material through the synergistic effect of Cu and Bi double doping, so that the thermoelectric material has excellent thermoelectric figure of merit.
[0005] The first aspect of the present application provides a modified MgAgSb-based thermoelectric material, the chemical formula of the modified MgAgSb-based thermoelectric material is Mg a Ag b Cu c Sb d Bi e , wherein the ratio of a, b, c, d and e is 1: (0.965-0.9625): (0.005-0.0075): (0.98-0.97): (0.01-0.02).
[0006] The MgAgSb-based thermoelectric material has three sites, i.e., Mg site, Ag site and Sb site, and different elements can be doped at any of the three sites. Due to the electronic properties of the doped elements and the differences in mass and atomic radius between the doped elements and the base elements, the effects of the elements doped at different sites are obviously different, and the same doped element doped at different sites also makes a huge difference in performance. The application adopts a double-doping strategy to obtain a modified MgAgSb-based thermoelectric material, specifically, a specific content of Cu element is doped at the Ag site, and a specific content of Bi element is doped at the Sb site. The Cu doping at the Ag site can improve the carrier concentration of the MgAgSb crystal, and the Bi doping at the Sb site can improve the band structure of the crystal, thereby improving the electrical properties of the thermoelectric material.
[0007] In addition, the double-doping strategy of Cu and Bi can produce a synergistic effect, which can further improve the electrical properties while simultaneously improving the thermal properties, so that the overall thermoelectric material has excellent thermoelectric figure of merit (zT value, which is an important parameter for measuring the efficiency of thermoelectric materials, and is related to the electrical properties and thermal properties of the material. A high zT value means that the thermoelectric performance of the material is excellent, and the material can efficiently convert electrical energy and thermal energy). The effective mass of the MgAgSb-based material doped with a single Cu or Bi does not change significantly. The effective mass of the thermoelectric material is closely related to the electrical properties and thermal properties, and the effective mass of the MgAgSb-based material doped with Cu-Bi increases first and then decreases with the increase of the doping amount, and the electrical properties of the thermoelectric material also increase first and then decrease. Although the overall zT value also increases first and then decreases, the change trend is not completely synchronized with the change trend of the electrical properties, because the thermal properties will also change with the change of the effective mass. The application selects a specific doping content of Cu and Bi to make the thermoelectric material have the most suitable effective mass range, and can have excellent electrical properties and thermal properties. Thus, the overall thermoelectric material has excellent zT value.
[0008] According to the embodiment of the application, the modified MgAgSb-based thermoelectric material comprises MgAg 0.965 Cu 0.005 Sb 0.97 Bi 0.02 . Thus, the modified MgAgSb-based thermoelectric material has the most suitable Cu and Bi double-doping content, so that the thermoelectric material has excellent electrical properties and thermal properties, and thus has extremely high thermoelectric conversion efficiency (zT value).
[0009] According to an embodiment of the present application, the modified MgAgSb-based thermoelectric material has a thermoelectric figure of merit (zT) of 0.83 or more at 27 DEG C. The thermoelectric figure of merit (zT) is an important parameter for measuring the thermoelectric conversion efficiency, and the higher the value, the better the thermoelectric performance. The modified MgAgSb-based thermoelectric material provided by the present application has an extremely high thermoelectric figure of merit at a temperature close to room temperature.
[0010] The second aspect of the present application provides a method for preparing the modified MgAgSb-based thermoelectric material of the first aspect, comprising: mixing Mg, Ag and Cu elements to perform a first grinding treatment to obtain a precursor; mixing the precursor, Sb and Bi elements to perform a second grinding treatment to obtain the modified MgAgSb-based thermoelectric material. Thus, the modified MgAgSb-based thermoelectric material can be prepared. The preparation method is simple and low in cost.
[0011] According to an embodiment of the present application, the first grinding treatment is performed for 8-10 hours. Thus, the first grinding treatment can be fully performed to enable the Cu element to be fully doped into the Ag site.
[0012] According to an embodiment of the present application, the second grinding treatment is performed for 5-7 hours. Thus, the second grinding treatment can be fully performed to enable the Bi element to be fully doped into the Sb site.
[0013] According to an embodiment of the present application, the first grinding treatment and the second grinding treatment are performed by ball milling. Thus, the product obtained by ball milling has low particle size and good uniformity, and ball milling has the advantage of high energy, which can fully realize the doping of elements in the alloy material.
[0014] According to an embodiment of the present application, the ball-to-material ratio of the ball milling in the first grinding treatment is (5-7):1. Thus, the ball milling in the first grinding treatment has a suitable ball-to-material ratio, which enables the ball milling to be fully performed to enable the Cu element to be fully doped into the Ag site.
[0015] According to an embodiment of the present application, the ball-to-material ratio of the ball milling in the second grinding treatment is (2-3):1. Thus, the ball milling in the second grinding treatment has a suitable ball-to-material ratio, which enables the ball milling to be fully performed to enable the Bi element to be fully doped into the Sb site.
[0016] According to an embodiment of the present application, the first grinding treatment and the second grinding treatment are performed in an inert atmosphere. Thus, the interference of impurities such as oxygen in the air can be reduced, the probability of impurity elements being incorporated into the product can be reduced, and the purity of the product can be improved.
[0017] The third aspect of the present application provides the use of the modified MgAgSb-based thermoelectric material of the first aspect or the modified MgAgSb-based thermoelectric material prepared by the method of the second aspect in a thermoelectric device.
[0018] Additional aspects and advantages of the present application will be in part apparent and in part expressly stated in the description that follows. BRIEF DESCRIPTION OF DRAWINGS
[0019] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the description of the embodiments, given in conjunction with the accompanying drawings. Figure 1 X-ray diffraction (XRD) pattern of the modified MgAgSb-based thermoelectric material prepared in Example 1 of the present application is shown. DETAILED DESCRIPTION
[0020] Embodiments of the present application are described in detail below. The embodiments described below are examples only and are not intended to limit the present application, as interpreted in its broadest form from the description hereof.
[0021] It should be noted that the terms "first", "second" and the like in the description do not necessarily connote an order or sequence and do not necessarily connote any priority. The terms "first", "second" and the like are used to distinguish one element from another but do not connote any priority or order. It should be noted that the terms "first", "second", and the like are used herein merely to identify one element from another and do not connote any priority or order. Thus, a "first" feature can be a "second" feature, and vice versa.
[0022] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The endpoints of the ranges and any values are provided as approximate descriptions of the ranges and are accomplished by varying the values within the range. Any numerical value, however, can be expressed as approximately that value, unless indicated otherwise. For example, a numeric range expressed as "1 to 5" can be approximated as "about 1 to about 5." Any numerical value, however, can be expressed as exactly that value, and not as "about that value," unless indicated otherwise.
[0023] In order that the present application can be more readily understood, certain technical and scientific terms are specifically defined below. Unless specifically defined herein, all other technical and scientific terms used in this document connotate the meanings that would be given to them by one of ordinary skill in the art of the present application.
[0024] In this document, the terms "comprises" and "comprising" are open-ended transition terms that are used to convey embodiments that can contain additional elements not expressly mentioned or otherwise included herein.
[0025] In this document, the terms "optionally", "optional" or "may" are used as antonyms for "must" and "must not". The use of these terms in this document is not intended to convey any formal or technical meaning.
[0026] The first aspect of the present application provides a modified MgAgSb-based thermoelectric material, the chemical formula of the modified MgAgSb-based thermoelectric material is Mg a Ag b Cu c Sb d Bi e , wherein the ratio of a, b, c, d and e is 1:(0.965-0.9625):(0.005-0.0075):(0.98-0.97):(0.01-0.02).
[0027] The MgAgSb-based thermoelectric material has three sites, i.e. Mg site, Ag site and Sb site, and different elements can be doped at any of the three sites. Due to the electronic properties of the doped elements and the differences in mass and atomic radius between the doped elements and the base elements, the doping of elements at different sites will bring about significantly different effects, and the doping of the same element at different sites will also make a huge difference in performance. The present application adopts a double-doping strategy to obtain a modified MgAgSb-based thermoelectric material, specifically, a specific amount of Cu element is doped at the Ag site, and a specific amount of Bi element is doped at the Sb site. The Cu doping at the Ag site can improve the carrier concentration of the MgAgSb crystal, and the Bi doping at the Sb site can improve the energy band structure of the crystal, thereby improving the electrical properties of the thermoelectric material.
[0028] In addition, the double-doping strategy of Cu and Bi can produce a synergistic effect, which can further improve the electrical properties and simultaneously improve the thermal properties, so that the overall thermoelectric material has excellent thermoelectric figure of merit (i.e. zT value, which is an important parameter for measuring the efficiency of thermoelectric materials, and is related to the electrical properties and thermal properties of the material. A high zT value means that the thermoelectric performance of the material is excellent, and the material can efficiently convert electrical energy and thermal energy). The effective mass of the MgAgSb-based material doped with a single element of Cu or Bi does not change significantly, and the effective mass of the thermoelectric material is closely related to the electrical properties and thermal properties. The effective mass of the MgAgSb-based material doped with Cu and Bi increases first and then decreases with the increase of the doping amount, and the electrical properties of the thermoelectric material also increase first and then decrease. Although the overall zT value also increases first and then decreases, the change trend is not completely synchronized with the change trend of the electrical properties, because the thermal properties will also change with the change of the effective mass. The present application selects a specific doping amount of Cu and Bi, so that the thermoelectric material has the most suitable effective mass range, and can have excellent electrical properties and thermal properties. Thus, the overall thermoelectric material has excellent zT value.
[0029] According to a specific embodiment of the present application, the modified MgAgSb-based thermoelectric material comprises MgAg 0.965 Cu 0.005Sb 0.97 Bi 0.02 Therefore, the modified MgAgSb-based thermoelectric material has the most suitable Cu and Bi doping content, so that the thermoelectric material has excellent electrical and thermal properties, and thus has extremely high thermoelectric conversion efficiency (i.e., zT value).
[0030] According to a specific embodiment of the present application, the thermoelectric figure of merit of the modified MgAgSb-based thermoelectric material at 27℃ is ≥0.83. The thermoelectric figure of merit, i.e., zT value, is an important parameter for measuring the thermoelectric conversion efficiency, and the higher the value, the more excellent the thermoelectric performance. The modified MgAgSb-based thermoelectric material provided by the present application has extremely high thermoelectric figure of merit at a temperature close to room temperature.
[0031] The second aspect of the present application provides a method for preparing the modified MgAgSb-based thermoelectric material of the first aspect, comprising: mixing Mg element, Ag element and Cu element, and performing first grinding treatment to obtain a precursor; mixing the precursor, Sb element and Bi element, and performing second grinding treatment to obtain the modified MgAgSb-based thermoelectric material. Therefore, the modified MgAgSb-based thermoelectric material described above can be prepared. The preparation method is simple and low in cost.
[0032] According to a specific embodiment of the present application, the first grinding treatment is performed for 8-10 hours.
[0033] As some specific examples, the first grinding treatment can be performed for 8 hours, 9 hours, 10 hours, etc. Therefore, the first grinding treatment can be performed sufficiently, so that the Cu element is sufficiently doped into the Ag site.
[0034] According to a specific embodiment of the present application, the second grinding treatment is performed for 5-7 hours.
[0035] As some specific examples, the second grinding treatment can be performed for 5 hours, 6 hours, 7 hours, etc. Therefore, the second grinding treatment can be performed sufficiently, so that the Bi element is sufficiently doped into the Sb site.
[0036] According to a specific embodiment of the present application, the manner of the first grinding treatment and the second grinding treatment is not particularly limited, including but not limited to ball milling. Therefore, the product obtained by ball milling has low particle size and good uniformity, and ball milling has the advantage of high energy, which can sufficiently realize the doping of elements in the alloy material.
[0037] According to a specific embodiment of the present application, the ball-to-material ratio of the first grinding treatment by ball milling is (5-7):1.
[0038] As some specific examples, the ball-to-material ratio of the ball milling in the first grinding process can be 5:1, 6:1, 7:1, etc. Thus, the ball milling in the first grinding process has a suitable ball-to-material ratio, so that the ball milling can be fully performed to sufficiently dope Cu element into Ag sites.
[0039] According to a specific embodiment of the present application, the ball-to-material ratio of the ball milling in the second grinding process is (2-3):1.
[0040] As some specific examples, the ball-to-material ratio of the ball milling in the second grinding process can be 2:1, 2.5:1, 3:1, etc. Thus, the ball milling in the second grinding process has a suitable ball-to-material ratio, so that the ball milling can be fully performed to sufficiently dope Bi element into Sb sites.
[0041] According to a specific embodiment of the present application, the first grinding process and the second grinding process are performed under an inert atmosphere, which is not particularly limited and includes, but is not limited to, argon. Thus, the interference of impurities such as oxygen in the air can be reduced, the probability of impurity elements being incorporated into the product can be reduced, and the purity of the product can be improved.
[0042] The third aspect of the present application provides a use of the modified MgAgSb-based thermoelectric material according to the first aspect or prepared by the method according to the second aspect in a thermoelectric device.
[0043] The scheme of the present application will be explained below in conjunction with examples. Those skilled in the art will understand that the following examples are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. If a specific technique or condition is not specified in the examples, the technique or condition described in the literature in the art or according to the product manual is used. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be obtained by purchase.
[0044] Example 1 The present example provides a modified MgAgSb-based thermoelectric material and a preparation method thereof, and the specific preparation steps are as follows: The raw materials were weighed according to the molar ratio of Mg:Ag:Cu:Sb:Bi = 1:0.965:0.005:0.97:0.02, specifically 0.9441 g of Mg element, 4.0436 g of Ag element and 0.0123 g of Cu element were weighed for the first ball milling, the time was 8 h, the ball-to-material ratio was 7:1, and the precursor was obtained; 4.3527 g of Sb element and 0.1540 g of Bi element were further weighed for the second ball milling with the precursor, the time was 5 h, the ball-to-material ratio was 3:1, and the modified MgAgSb-based thermoelectric material was prepared, and the X-ray diffraction (XRD) spectrum thereof is shown in Figure 1 The chemical formula of the modified MgAgSb-based thermoelectric material prepared in the present example is MgAg0.965 Cu 0.005 Sb 0.97 Bi 0.02 .
[0045] Depend on Figure 1 It can be seen that the overall crystal structure of the sample in Example 1 did not change significantly due to the small amount of doping, which was insufficient to affect the overall structure. However, the disappearance of the MgAg impurity peak in the 20°~40° range due to Cu doping, and the alteration of the original Mg-Sb distorted rock salt phase due to the larger atomic size of Bi compared to Sb, resulted in the broadening of the 40° main peak position. This indicates that Cu and Bi successfully entered the crystal lattice and the doping was effective.
[0046] Example 2 This embodiment provides a modified MgAgSb-based thermoelectric material and its preparation method. The specific preparation steps are as follows: The raw materials were weighed according to the molar ratio of Mg:Ag:Cu:Sb:Bi = 1:0.965:0.005:0.98:0.01. Specifically, 0.9441 g of elemental Mg, 4.0436 g of elemental Ag, and 0.0123 g of elemental Cu were ball-milled for 10 hours at a ball-to-material ratio of 5:1 to obtain the precursor. Then, 4.4388 g of elemental Sb and 0.0777 g of elemental Bi were ball-milled with the precursor for 7 hours at a ball-to-material ratio of 2:1 to obtain the modified MgAgSb-based thermoelectric material. The chemical formula of the modified MgAgSb-based thermoelectric material obtained in this embodiment is MgAg 0.965 Cu 0.005 Sb 0.98 Bi 0.01 .
[0047] Example 3 The difference between this embodiment and Example 1 is that the raw materials were weighed according to the molar ratio of Mg:Ag:Cu:Sb:Bi = 1:0.9625:0.0075:0.97:0.02, while the other steps remained unchanged. The chemical formula of the modified MgAgSb-based thermoelectric material prepared in this embodiment is MgAg 0.9625 Cu 0.0075 Sb 0.97 Bi 0.02 .
[0048] Comparative Example 1 The difference between this comparative example and Example 1 is that the raw materials were weighed according to the molar ratio of Mg:Ag:Sb = 1:0.97:0.99, while the other steps remained the same. The chemical formula of the thermoelectric material prepared in this comparative example is MgAg 0.97 Sb 0.99 .
[0049] Comparative Example 2 The difference between this comparative example and Example 1 is that the raw materials are weighed according to the molar ratio of Mg:Ag:Cu:Sb = 1:0.965:0.005:0.99, and the remaining steps are unchanged. The chemical formula of the thermoelectric material prepared in this comparative example is MgAg 0.965 Cu 0.005 Sb 0.99 .
[0050] Comparative Example 3 The difference between this comparative example and Example 1 is that the raw materials are weighed according to the molar ratio of Mg:Ag:Sb:Bi = 1:0.97:0.97:0.02, and the remaining steps are unchanged. The chemical formula of the thermoelectric material prepared in this comparative example is MgAg 0.97 Sb 0.97 Bi 0.02 .
[0051] Comparative Example 4 The difference between this comparative example and Example 1 is that the raw materials are weighed according to the molar ratio of Mg:Ag:Cu:Sb:Bi = 1:0.965:0.005:0.96:0.03, and the remaining steps are unchanged. The chemical formula of the thermoelectric material prepared in this comparative example is MgAg 0.965 Cu 0.005 Sb 0.96 Bi 0.03 .
[0052] Comparative Example 5 The difference between this comparative example and Example 1 is that the raw materials are weighed according to the molar ratio of Mg:Ag:Cu:Sb:Bi = 1:0.965:0.005:0.95:0.04, and the remaining steps are unchanged. The chemical formula of the thermoelectric material prepared in this comparative example is MgAg 0.965 Cu 0.005 Sb 0.95 Bi 0.04 .
[0053] Test Example The performance of the thermoelectric materials prepared in the above examples and comparative examples is tested, and the specific test method is as follows: (1) zT value test at 27°C (i.e. 300K): The thermoelectric material is cut into a strip with a thickness of 2.5mm and a width of 2.5mm, and the cut sample is polished with sandpaper and polishing paper before being measured by a Seebeck coefficient tester (i.e. ZEM-3, which can simultaneously measure the Seebeck coefficient and electrical conductivity of the thermoelectric material) from 27°C to 277°C. The electrical conductivity and Seebeck coefficient are measured simultaneously. According to , where S is the Seebeck coefficient (unit: μV / K), σ (S·cm -1) The PF (power factor) value of the sample is obtained by software analysis of the conductivity. The thermoelectric material is cut into a disc with a thickness of 1-2 mm, and the thermal diffusivity D is measured by a laser thermal conductivity coefficient measuring instrument LFA467, and the thermal conductivity κ is calculated according to κ = D * C p / λ p wherein D is the density of the sample (g·cm -3 ); Cp is the measured thermal diffusivity (mm 2 / s); is the specific heat of the sample (J / (kg·K)); is the thermal conductivity (W / (m·K));
[0054] (2) Average zT value test: The average zT value is calculated from the zT values at each temperature obtained in (1).
[0055] The performance test results of the thermoelectric materials prepared in the examples and comparative examples are shown in Table 1.
[0056] Table 1
[0057] Result analysis: Compared with Comparative Examples 1-5, the thermoelectric materials prepared in Examples 1-3 have excellent electrical and thermal properties by doping Cu and Bi in specific amounts, thereby having a higher zT value at a temperature close to room temperature (i.e., 27℃) and a higher average zT value.
[0058] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.
[0059] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.
Claims
1. A modified MgAgSb-based thermoelectric material, characterized by, The modified MgAgSb-based thermoelectric material has a chemical formula of Mg a Ag b Cu c Sb d Bi e , wherein a, b, c, d, e are in a ratio of 1:(0.965-0.9625):(0.005-0.0075):(0.98-0.97):(0.01-0.02).
2. The modified MgAgSb-based thermoelectric material according to claim 1, characterized in that, The modified MgAgSb-based thermoelectric material includes MgAg 0.965 Cu 0.005 Sb 0.97 Bi 0.02 .
3. The modified MgAgSb-based thermoelectric material of claim 1, wherein, The thermoelectric figure of merit of the modified MgAgSb-based thermoelectric material at 27 DEG C is greater than or equal to 0.
83.
4. A method of producing the modified MgAgSb-based thermoelectric material according to any one of claims 1 to 3, characterized by, The method comprises the following steps: Mixing Mg element, Ag element and Cu element, and performing first grinding treatment to obtain a precursor; Mixing the precursor, Sb element and Bi element, and performing second grinding treatment to obtain the modified MgAgSb-based thermoelectric material.
5. The method of claim 4, wherein, The first grinding treatment is performed for 8-10 hours.
6. The method of claim 4, wherein, The second grinding treatment is performed for 5-7 hours.
7. The method according to any one of claims 4-6, characterized in that, The first grinding treatment and the second grinding treatment are performed by ball milling.
8. The method of claim 7, wherein, The ball-to-material ratio of the ball milling in the first grinding treatment is (5-7):
1. Optionally, the ball-to-material ratio of the ball milling in the second grinding treatment is (2-3):
1.
9. The method according to any one of claims 4-6, characterized in that, The first grinding treatment and the second grinding treatment are performed in an inert atmosphere.
10. Use of the modified MgAgSb-based thermoelectric material according to any one of claims 1-3 or the modified MgAgSb-based thermoelectric material prepared by the method according to any one of claims 4-9 in a thermoelectric device.