Thermoelectric interface material, bismuth antimony tellurium-based thermoelectric composite material containing the interface layer and preparation method and application thereof

Abstract

The application discloses a thermoelectric interface material, a BiSbTe-based thermoelectric composite material containing the interface layer, and a preparation method and application thereof. a Fe b Mo c W d V e , wherein a=10-30; b=10-40; c=10-40; d=10-40; e=10-40, and a, b, c, d and e respectively represent atomic percentages of the elements. The BiSbTe-based thermoelectric composite material containing the thermoelectric interface material comprises a thermoelectric conversion material and the thermoelectric interface material which is compounded to at least part of a surface of the thermoelectric conversion material. The interface material disclosed by the application is highly matched with a thermal expansion coefficient of the BiSbTe-based thermoelectric conversion material, the interface shear strength of the composite material reaches 14.96 MPa in a synthetic state, is increased to 24.55 MPa after 7 days of service at 200 DEG C, the contact resistivity is extremely low and stable, the diffusion resistance is strong, and the technical problems of low interface bonding strength and poor high-temperature service stability in existing thermoelectric devices are effectively solved, and the application is suitable for the field of thermoelectric devices such as single-leg thermoelectric devices.

Description

Technical Field

[0001] This invention relates to thermoelectric device technology, and more particularly to a thermoelectric interface material, a BiSbTe-based thermoelectric composite material containing the interface layer, and its preparation method and application. Background Technology

[0002] Due to the excessive consumption of fossil fuels and the resulting environmental pollution, the global demand for renewable resources and energy conversion efficiency is constantly growing. Thermoelectric materials are functional materials that utilize the Seebeck and Peltier effects to achieve the interconversion of thermal and electrical energy. Among them, Bi... 0.5 Sb 1.5 Te3 thermoelectric materials possess excellent thermoelectric properties and are among the most promising low-temperature thermoelectric materials for application in recent years. However, the assembly and reliability of thermoelectric devices are the biggest challenges to their practical application, with the contact interface between the thermoelectric material and the electrodes being particularly critical.

[0003] Currently, thermoelectric devices are typically assembled using brazing or soldering. Most thermoelectric materials exhibit poor weldability due to their semiconductor properties; therefore, a metallization layer is required between the thermoelectric material and the electrode to achieve a reliable bond. Numerous single-metal barrier layers have been studied, but their interfacial reactions limit the improvement of bond strength, resulting in weak interfacial bonding. In relatively high-temperature operating environments, poor interfacial bonding strength can further lead to mechanical failure of the device.

[0004] To address the aforementioned issues, while the industry has attempted to develop multi-element alloy interface materials, existing solutions have not fully considered interfacial reaction regulation, thermal expansion matching, and long-term service stability, and thus still cannot fully meet the requirements for high-performance Bi alloys. 0.5 Sb 1.5 Packaging requirements for Te3 thermoelectric devices. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing Bi... 0.5 Sb 1.5 Te3 thermoelectric devices suffer from low interfacial bonding strength and insufficient high-temperature service stability due to their single-metal or simple alloy interface layers, failing to meet the requirements for long-term reliable operation. To address this, a thermoelectric interface material is proposed that is well-compatible with BiSbTe thermoelectric conversion materials. The BiSbTe-based thermoelectric composite material containing this interface layer achieves low contact resistivity while possessing high interfacial bonding strength and excellent high-temperature service stability, effectively solving the interface failure problem of existing thermoelectric devices.

[0006] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0007] To achieve the above objectives, the technical solution adopted by this invention is: a thermoelectric interface material with the general chemical formula: Cr a Fe b Mo c W d V e Where a = 10–30; b = 10–40; c = 10–40; d = 10–40; e = 10–40, and a, b, c, d, and e represent the atomic percentages of each element.

[0008] Furthermore, the general chemical formula of the thermoelectric interface material is: Cr a Fe b Mo c W d V e Where a = 15–25; b = 15–25; c = 15–25; d = 15–25; e = 15–25, and a, b, c, d, and e represent the atomic percentage of each element.

[0009] Another objective of this invention discloses a method for preparing a thermoelectric interface material, comprising the following steps: mixing the raw materials according to a specified ratio, ball milling under inert gas protection to obtain alloy powder, which is the thermoelectric interface material. That is, the thermoelectric interface material of this invention is prepared by mechanical alloying.

[0010] Furthermore, the ball milling time is 10 to 15 hours.

[0011] Another objective of this invention is to disclose the application of a thermoelectric interface material in the fabrication of thermoelectric devices.

[0012] Another object of the present invention discloses a BiSbTe-based thermoelectric composite material containing a thermoelectric interface material, comprising a thermoelectric conversion material (TEcM) and the thermoelectric interface material (TEiM) composited to at least a portion of the surface of the thermoelectric conversion material.

[0013] Furthermore, the thermoelectric conversion material is composite with a thermoelectric interface material on one or both sides.

[0014] Furthermore, the thermoelectric conversion material is a p-type thermoelectric conversion material.

[0015] Furthermore, the thermoelectric conversion material is a p-type Bi. f Sb g Teh Thermoelectric conversion material, wherein f=0.1~1, g=1~2, h=2~4, where f, g, and h represent the atomic percentage of each element.

[0016] Furthermore, the thermoelectric conversion material is a p-type Bi. f Sb g Te h Thermoelectric conversion material, wherein f=0.3~0.6, g=1.3~1.7, h=2~4, where f, g, and h represent the atomic percentage of each element.

[0017] Furthermore, the thermoelectric conversion material is a p-type Bi. 0.5 Sb 1.5 Te3 thermoelectric conversion material.

[0018] Furthermore, the thickness of the thermoelectric conversion material is 4–6 mm.

[0019] Furthermore, the thickness of the thermoelectric interface material layer is 0.2–0.4 mm.

[0020] Furthermore, the interface of the BiSbTe-based thermoelectric composite material containing the thermoelectric interface material not only possesses excellent comprehensive properties after synthesis, with a shear strength >10 MPa and a contact resistivity <10 µΩ·cm, but also exhibits excellent overall performance. 2 The diffusion layer thickness is <10 µm. Furthermore, after 7 days of service at 200℃, it still exhibits high shear strength >20 MPa and low contact resistivity <10 µΩ·cm. 2 The diffusion layer thickness is <10 µm.

[0021] Furthermore, the interface of the BiSbTe-based thermoelectric composite material containing the thermoelectric interface material not only possesses excellent comprehensive properties after synthesis, with a shear strength of 10 MPa to 14.23 MPa and a contact resistivity of 10 µΩ·cm, but also exhibits excellent overall performance. 2 ~2.13µΩ·cm 2 The diffusion layer thickness is 0.5–3 µm. Furthermore, after 7 days of service at 200°C, it still exhibits high shear strength of 20 MPa–26.12 MPa and low contact resistivity of 10 µΩ·cm. 2 ~2.77µΩ·cm 2 The diffusion layer thickness is 0.5–3 µm.

[0022] Furthermore, the preparation method of the thermoelectric conversion material includes: mixing the raw materials according to the formula, ball milling for 10 to 13 hours under inert gas protection to obtain thermoelectric conversion material powder.

[0023] Furthermore, the rate of heating to the sintering temperature during the preparation of the thermoelectric conversion material is 50–100 °C / min. -1 .

[0024] Another objective of this invention discloses a method for preparing a BiSbTe-based thermoelectric composite material containing a thermoelectric interface material, comprising: placing the thermoelectric interface material onto at least a portion of the surface of a thermoelectric conversion material, and subjecting it to sintering treatment to obtain the BiSbTe-based thermoelectric composite material containing the thermoelectric interface material.

[0025] Furthermore, the sintering process is spark plasma sintering.

[0026] Furthermore, the temperature of the discharge plasma sintering is 400–600°C, preferably 400°C.

[0027] Furthermore, the discharge plasma sintering time is 5 to 10 minutes.

[0028] Furthermore, the axial pressure of the discharge plasma sintering is 60-100 MPa, preferably 80 MPa.

[0029] Furthermore, the heating rate to the discharge plasma sintering temperature is 50–100 °C / min.

[0030] Furthermore, the raw materials used to prepare thermoelectric conversion materials and thermoelectric interface materials are all elemental raw materials.

[0031] Furthermore, the particle size of each elemental raw material is 200-400 mesh, and the purity is greater than 98%.

[0032] Furthermore, the specific raw materials of each element are as follows:

[0033] Cr powder, 200 mesh, 98% purity.

[0034] Fe powder, 300 mesh, 99.9% purity.

[0035] Mo powder, 250 mesh, 99% purity.

[0036] W powder, 250 mesh, 99% purity.

[0037] V-powder, 250 mesh, 99% purity.

[0038] Bi particles, φ3mm, purity 99.95%.

[0039] Sb particles, φ3mm, purity 99.95%.

[0040] Te particles, φ3mm, purity 99.995%.

[0041] Furthermore, when preparing thermoelectric conversion materials and thermoelectric interface materials, the inert gas includes, but is not limited to, at least one of nitrogen (N2), helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe).

[0042] Another objective of this invention is to disclose the application of a BiSbTe-based thermoelectric composite material containing a thermoelectric interface material in the field of thermoelectric devices.

[0043] Furthermore, the thermoelectric device is a single-leg thermoelectric device.

[0044] The thermoelectric interface material, the BiSbTe-based thermoelectric composite material containing the interface layer, the preparation method and application of the present invention have the following advantages compared with the prior art:

[0045] (I) This invention provides a chemical formula of Cr a Fe b Mo c W d V e A high-entropy thermoelectric interface material was developed, wherein a = 10–30, b = 10–40, c = 10–40, d = 10–40, and e = 10–40. Through a rational multi-principal-element high-entropy design, this thermoelectric interface material forms a stable solid solution structure, effectively suppressing the concentrated formation of brittle intermetallic compounds at the interface and significantly improving the intrinsic physicochemical properties of the interface material.

[0046] (II) The BiSbTe-based thermoelectric composite material containing thermoelectric interface material described in this invention possesses excellent interfacial bonding strength. Experiments show that Cr 20 Fe 20 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 The initial shear strength of the Te3 composite interface reached 14.96 MPa, far exceeding the industry standard of 10 MPa. After aging at 200℃ for 7 days, the interfacial shear strength further increased to 24.55 MPa, exhibiting significant high-temperature self-reinforcing characteristics. This indicates that a beneficial diffusion and densification process occurred at the interface under high-temperature service conditions, ensuring the mechanical reliability of the device under long-term high-temperature conditions.

[0047] (III) The BiSbTe-based thermoelectric composite material containing thermoelectric interface material described in this invention has an extremely low and stable contact resistivity of 10 µΩ·cm. 2 ~2.13µΩ·cm 2 The composite material interface maintained an extremely low contact resistivity of 10 µΩ·cm in both the synthesized state and after aging at 200°C for 7 days. 2~2.77µΩ·cm 2 Furthermore, the change in contact resistivity is minimal over time. Low contact resistivity means that thermoelectric devices have less Joule heat loss and higher output efficiency during energy conversion, while the high-temperature stability of contact resistivity ensures the continuous reliability of electrical performance throughout the device's entire lifespan.

[0048] (iv) Scanning electron microscopy and elemental distribution analysis show that a continuous, dense diffusion bonding layer with a smooth elemental transition is formed between the Cr-Fe-Mo-WV system and the BiSbTe-based thermoelectric conversion material, which avoids the generation of harmful reaction layers or elemental segregation, thus obtaining better comprehensive indicators of shear strength and contact resistivity.

[0049] (V) The preparation method of the thermoelectric interface material and the BiSbTe-based thermoelectric composite material containing the interface layer described in this invention is simple and highly compatible. Both the thermoelectric interface material and the thermoelectric conversion material adopt a process route of mechanical alloying combined with spark plasma sintering. The sintering temperature window for both is 400–600℃, and the axial pressure window is 60–100MPa. The sandwich structure can be integrally formed in a single sintering process without the need for additional brazing, plating, or intermediate heat treatment. This preparation method is simple to operate, the process is controllable, and the reproducibility is good, making it suitable for industrial-scale production.

[0050] (vi) The raw materials used in this invention, such as chromium, iron, molybdenum, tungsten, vanadium, bismuth, antimony and tellurium, are all commonly used industrial raw materials. Among them, the metal powder used in the interface material only needs a particle size of 200 to 400 mesh and a purity of more than 98% to achieve excellent performance. The raw materials are widely available and the prices are stable, which has good economic benefits and prospects for large-scale promotion and application.

[0051] (vii) The BiSbTe-based thermoelectric composite material containing thermoelectric interface material of the present invention exhibits an interfacial shear strength greater than 20 MPa and a contact resistivity less than 10 μΩ·cm after both the synthesized state and 7 days of service at 200°C. 2 Meeting industry requirements, it comprehensively considers mechanical bonding strength, electrical contact characteristics, and thermal compatibility, solving the problems of existing Bi 0.5 Sb 1.5 Te3 addresses common technical challenges in thermoelectric devices, such as weak interfacial bonding strength between thermoelectric materials and electrodes, poor high-temperature service stability, and high contact resistivity, providing an effective material solution for the development and practical application of high-performance, high-reliability thermoelectric devices. Attached Figure Description

[0052] Figure 1 For Cr 20 Fe 20 Mo 20 W 20 V 20SEM image of / TEcM thermoelectric composite material;

[0053] Figure 2 For Cr 15 Fe 15 Mo 20 W 20 V 15 Nb 15 SEM image of / TEcM thermoelectric composite material;

[0054] Figure 3 Cr annealed to 473K for 7 days 20 Fe 20 Mo 20 W 20 V 20 SEM image of / TEcM thermoelectric composite material;

[0055] Figure 4 Cr annealed to 473K for 7 days 15 Fe 15 Mo 20 W 20 V 15 Nb 15 SEM image of / TEcM thermoelectric composite material;

[0056] Figure 5 For Cr 20 Fe 20 Mo 20 W 20 V 20 Shear strength diagram of / TEcM thermoelectric composite material;

[0057] Figure 6 For Cr 20 Fe 20 Mo 20 W 20 V 20 Shear strength diagram of / TEcM thermoelectric composite material after annealing at 200℃ for 7 days;

[0058] Figure 7 Cr in Example 1 20 Fe 20 Mo 20 W 20 V 20 / TEcM and Cr of Comparative Example 1 15 Fe 15 Mo 20 W 20 V 15 Nb 15 / TEcM thermoelectric composite material contact resistance diagram;

[0059] Figure 8Cr in Example 1 20 Fe 20 Mo 20 W 20 V 20 / TEcM and Cr of Comparative Example 1 15 Fe 15 Mo 20 W 20 V 15 Nb 15 Contact resistance diagram of / TEcM thermoelectric composite material after annealing at 200°C for 7 days, where A is Cr from Example 1. 20 Fe 20 Mo 20 W 20 V 20 / TEcM, B is Cr from Comparative Example 1 15 Fe 15 Mo 20 W 20 V 15 Nb 15 / TEcM. Detailed Implementation

[0060] The present invention will be further described below with reference to embodiments. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0061] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0062] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0063] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0064] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0065] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0066] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0067] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0068] Example 1

[0069] This embodiment discloses a BiSbTe-based thermoelectric composite material Cr containing a high-entropy thermoelectric interface material. 20 Fe 20 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 Te3 includes a thermoelectric conversion material (TEcM) and a thermoelectric interface material (TEiM) composited to at least a portion of the surface of the thermoelectric conversion material. The chemical formula of TEcM is as follows: Bi 0.5 Sb 1.5 The chemical formulas for Te3 and TEiM are as follows: Cr 20 Fe 20 Mo 20 W 20 V 20 .

[0070] The preparation method of the BiSbTe-based thermoelectric composite material containing the high-entropy thermoelectric interface material is as follows:

[0071] Preparation of TEcM: Weigh each elemental raw material according to the designed ratio, and then ball mill (stainless steel ball, diameter 10mm) for 12 hours under argon protection to obtain TEcM powder.

[0072] Preparation of TEiM: Weigh each elemental raw material according to the design ratio, and obtain alloy powder by high-energy ball milling (tungsten carbide balls with a diameter of 5 mm) for 10-11 hours under argon protection using mechanical alloying method.

[0073] BiSbTe-based thermoelectric composites containing high-entropy thermoelectric interface materials Cr 20 Fe 20 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 Preparation of Te3: First, sample loading was performed, specifically by placing TEcM powder in a graphite mold, between the upper and lower TeiM powders, forming a sandwich-like structure. Then, spark plasma sintering was performed. The TEiM powder and TEcM powder formed a TEiM / TEcM contact interface through spark plasma sintering at 400℃ for 10 min and 80 MPa axial pressure. The heating rate during sintering was 100℃*min. -1The thicknesses of the TEcM block and the TEiM layer are designed to be 4 mm and 0.3 mm, respectively.

[0074] Example 2

[0075] This embodiment discloses a BiSbTe-based thermoelectric composite material Cr containing a high-entropy thermoelectric interface material. 15 Fe 25 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 Te3 includes a thermoelectric conversion material (TEcM) and a thermoelectric interface material (TEiM) composited to at least a portion of the surface of the thermoelectric conversion material. The chemical formula of TEcM is as follows: Bi 0.5 Sb 1.5 The chemical formulas for Te3 and TEiM are as follows: Cr 15 Fe 25 Mo 20 W 20 V 20 .

[0076] The preparation method of the BiSbTe-based thermoelectric composite material containing the high-entropy thermoelectric interface material is as follows:

[0077] Preparation of TEcM: Weigh each elemental raw material according to the designed ratio, and then ball mill (stainless steel ball, diameter 10mm) for 12 hours under argon protection to obtain TEcM powder.

[0078] Preparation of TEiM: Weigh each elemental raw material according to the design ratio, and obtain alloy powder by high-energy ball milling (tungsten carbide balls with a diameter of 5 mm) for 10-11 hours under argon protection using mechanical alloying method.

[0079] BiSbTe-based thermoelectric composites containing high-entropy thermoelectric interface materials Cr 15 Fe 25 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 Preparation of Te3: First, sample loading was performed, specifically by placing TEcM powder in a graphite mold, between the upper and lower TeiM powders, forming a sandwich-like structure. Then, spark plasma sintering was performed. The TEiM powder and TEcM powder formed a TEiM / TEcM contact interface through spark plasma sintering at 400℃ for 10 min and 80 MPa axial pressure. The heating rate during sintering was 100℃*min. -1 The thicknesses of the TEcM block and the TEiM layer are designed to be 4 mm and 0.3 mm, respectively.

[0080] Table 1 shows the Cr content in Example 2. 15 Fe 25 Mo 20 W 20 V 20 / TecM's performance indicators

[0081]

[0082] Example 3

[0083] This embodiment discloses a BiSbTe-based thermoelectric composite material Cr containing a high-entropy thermoelectric interface material. 25 Fe 15 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 Te3 includes a thermoelectric conversion material (TEcM) and a thermoelectric interface material (TEiM) composited to at least a portion of the surface of the thermoelectric conversion material. The chemical formula of TEcM is as follows: Bi 0.5 Sb 1.5 The chemical formulas for Te3 and TEiM are as follows: Cr 25 Fe 15 Mo 20 W 20 V 20 .

[0084] The preparation method of the BiSbTe-based thermoelectric composite material containing the high-entropy thermoelectric interface material is as follows:

[0085] Preparation of TEcM: Weigh each elemental raw material according to the designed ratio, and then ball mill (stainless steel ball, diameter 10mm) for 12 hours under argon protection to obtain TEcM powder.

[0086] Preparation of TEiM: Weigh each elemental raw material according to the design ratio, and obtain alloy powder by high-energy ball milling (tungsten carbide balls with a diameter of 5 mm) for 10-11 hours under argon protection using mechanical alloying method.

[0087] BiSbTe-based thermoelectric composites containing high-entropy thermoelectric interface materials Cr 25 Fe 15 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5Preparation of Te3: First, sample loading was performed, specifically by placing TEcM powder in a graphite mold, between the upper and lower TeiM powders, forming a sandwich-like structure. Then, spark plasma sintering was performed. The TEiM powder and TEcM powder formed a TEiM / TEcM contact interface through spark plasma sintering at 400℃ for 10 min and 80 MPa axial pressure. The heating rate during sintering was 100℃*min. -1 The thicknesses of the TEcM block and the TEiM layer are designed to be 4 mm and 0.3 mm, respectively.

[0088] Table 2 Cr in Example 3 25 Fe 15 Mo 20 W 20 V 20 / TecM's performance indicators

[0089]

[0090] Comparative Example 1

[0091] This comparative example discloses a composite material Cr 15 Fe 15 Mo 20 W 20 V 15 Nb 15 / Bi 0.5 Sb 1.5 The chemical formulas for Te3 and TEcM are as follows: Bi 0.5 Sb 1.5 The chemical formulas for Te3 and TEiM are as follows: Cr 15 Fe 15 Mo 20 W 20 V 15 Nb 15 Its preparation method is the same as that in Example 1.

[0092] The BiSbTe-based thermoelectric composites containing high-entropy thermoelectric interface materials in Examples 1-3 were respectively compared. 20 Fe 20 Mo 20 W 20 V 20 / Bi 0.5 Sb 1.5 The composite material of Te3 and Comparative Example 1 Cr 15 Fe 15 Mo 20 W 20 V 15 Nb 15 / Bi 0.5 Sb 1.5The Te3 was tested, and the test methods and results are as follows:

[0093] The diffusion barrier properties, shear strength, and contact resistivity between the thermoelectric interface material (TEiM) and the thermoelectric conversion material (TEcM) in the embodiment are all at ideal levels. Figure 1 As shown, the interface in Example 1 shows good bonding and no diffusion. Figure 2 As shown, the interface bonding in Comparative Example 1 is also excellent, with no diffusion. Figure 3 As shown, after annealing at 473K for 7 days, the interface bonding in Example 1 remained good, with no diffusion. Figure 4 As shown, after annealing at 473K for 7 days, the interface bonding in Comparative Example 1 remained good, with no diffusion. Figure 5 As shown, Example 1 and Bi 0.5 Sb 1.5 The Te3 bonding strength is 14.96 MPa, while the industry standard is >10 MPa, indicating that it is significantly higher than the industry standard. For example... Figure 6 As shown, after annealing at 473K for 7 days, Example 1 and Bi 0.5 Sb 1.5 The Te3 bonding strength is 24.55 MPa, while the industry standard is >10 MPa, indicating that the Te3 bond strength is significantly higher than the industry standard, demonstrating high thermal stability. For example... Figure 7 As shown, Example 1 and Comparative Example 1 are similar to Bi. 0.5 Sb 1.5 The contact resistivity at the Te3 interface is extremely low (<10 µΩ·cm). 2 ).like Figure 8 As shown, after annealing at 473K for 7 days, Examples 1 and Comparative Example 1 were compared with Bi. 0.5 Sb 1.5 The contact resistivity at the Te3 interface is extremely low (<10 µΩ·cm). 2 It exhibits high thermal stability. As shown in Table 1, the Cr in Example 2... 15 Fe 25 Mo 20 W 20 V 20 All performance indicators of / TecM exceed industry standards. As shown in Table 2, the Cr in Example 3 25 Fe 15 Mo 20 W 20 V 20 / TecM's performance indicators all exceed industry standards.

[0094] Shear strength and contact resistivity tests shall be conducted in accordance with the general standards of this industry. For detailed test procedures, please refer to Section 2.2 (page 2, paragraph 3) of Acta Materialia 226 (2022) 117616.

[0095] A vacuum-sealed tube was used to simulate a high-temperature environment for heat treatment of the material. The interface was placed in a quartz tube, and a vacuum was drawn until the vacuum level reached 10. -3 After Pa, the quartz tube was sealed with a flame gun, and then placed in a muffle furnace. The temperature was increased to 200°C at a rate of 7°C / min, and held for different times to simulate the actual service environment of the device. Figure 3 , 4 As shown in Figures 6 and 8, based on the slopes of the interfacial shear strength and contact resistivity changes with time, it can be seen that under different service times at 200℃, Cr 20 Fe 20 Mo 20 W 20 V 20 The shear strength of the / TEcM interface shows a very small trend over time, indicating that this thermoelectric interface material is most beneficial for improving the thermal stability of the interface. After 7 days of service, Cr 20 Fe 20 Mo 20 W 20 V 20 The shear strength of the / TEcM interface increased from 14.96 MPa to 24.55 MPa, both significantly exceeding the qualified interface shear strength of 10 MPa. Cr 20 Fe 20 Mo 20 W 20 V 20 The / TEcM interface exhibits extremely low and stable contact resistivity. After 7 days of service at 200℃, the contact interface still meets the requirements of bonding strength >10 MPa and contact resistivity <10 μΩ*cm. 2 This meets industry requirements and offers competitive interface stability performance within the current industry.

[0096] The reliability of thermoelectric devices largely depends on the interfacial contact between the thermoelectric material and the electrodes. In one embodiment, the present invention provides a high-entropy alloy, and the thermoelectric device prepared using this type of high-entropy alloy exhibits an interfacial shear strength >10 MPa and extremely low contact resistivity. Furthermore, after 7 days of service at 200°C, the shear strength of the contact interface is >20 MPa, and the contact resistivity remains extremely low.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermoelectric interface material, characterized in that, The general chemical formula is: Cr a Fe b Mo c W d V e Where a = 10–30; b = 10–40; c = 10–40; d = 10–40; e = 10–40, and a, b, c, d, and e represent the atomic percentages of each element.

2. A method for preparing the thermoelectric interface material according to claim 1, characterized in that, The process includes the following steps: mixing the raw materials according to the specified ratio, ball milling under inert gas protection to obtain alloy powder, which is the thermoelectric interface material.

3. The application of the thermoelectric interface material of claim 1 in the field of thermoelectric device fabrication.

4. A BiSbTe-based thermoelectric composite material containing a thermoelectric interface material, characterized in that, The thermoelectric interface material of claim 1 includes thermoelectric conversion materials and composites to at least a portion of the surface of thermoelectric conversion materials.

5. The BiSbTe-based thermoelectric composite material containing a thermoelectric interface material according to claim 4, characterized in that, The thermoelectric conversion material is a p-type thermoelectric conversion material, and the thermoelectric conversion material is a p-type Bi f Sb g Te h Thermoelectric conversion material, wherein f=0.1~1, g=1~2, h=2~4, where f, g, and h represent the atomic percentage of each element.

6. The BiSbTe-based thermoelectric composite material containing a thermoelectric interface material according to claim 4, characterized in that, The thickness of the thermoelectric conversion material is 4-6 mm; And / or, the thickness of the thermoelectric interface material layer is 0.2 to 0.4 mm.

7. A method for preparing a BiSbTe-based thermoelectric composite material containing a thermoelectric interface material as described in any one of claims 4-6, characterized in that, include: A thermoelectric interface material is placed on at least a portion of the surface of a thermoelectric conversion material, and then sintered to obtain the BiSbTe-based thermoelectric composite material containing the thermoelectric interface material.

8. The method for preparing the BiSbTe-based thermoelectric composite material containing a thermoelectric interface material according to claim 7, characterized in that, The sintering process is spark plasma sintering, and the temperature of spark plasma sintering is 400-600℃. And / or, the time for the discharge plasma sintering is 5 to 10 minutes; And / or, the axial pressure of the discharge plasma sintering is 60-100 MPa; And / or, the heating rate to the discharge plasma sintering temperature is 50–100 °C / min.

9. The application of a BiSbTe-based thermoelectric composite material containing a thermoelectric interface material as described in any one of claims 4-6 in the field of thermoelectric devices.

10. The application according to claim 9, characterized in that, The thermoelectric device is a single-leg thermoelectric device.

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