A kind of Bi 1-x Sb x Single crystal materials, thermoelectric refrigeration devices and their preparation methods and applications

Abstract

The application relates to a Bi 1‑x Sb x Single crystal material, thermoelectric refrigeration device and preparation method and application thereof. The Bi 1‑x Sb x Single crystal material is prepared through a zone melting technique, is uniform in composition and consistent in orientation; wherein the Bi 1‑x Sb x In the single crystal material, the value range of x is 0.1-0.15. Subsequently, the Bi 1‑x Sb x Single crystal thermoelectric leg and BiSbTe thermoelectric leg are obtained by using Bi 0.58 Sn 0.42 Solder is welded to an aluminum nitride ceramic plate with a Cu coating, and a Bi 1‑x Sb x Based single-stage thermoelectric refrigeration device; the refrigeration device can be further improved in refrigeration capacity in a cascade assembly mode through solder, the lowest refrigeration temperature of a six-stage refrigeration device prepared by the application can reach 130K, and the application is suitable for cooling application of high-temperature superconductors, the transition of YBa2Cu3O7 high-temperature superconductor from a normal state to a superconducting state is successfully realized, and the application shows a broad application prospect in the low-temperature field.

Description

Technical Field

[0001] This invention relates to the field of thermoelectric refrigeration technology, and in particular to a Bi 1-x Sb x Single crystal materials, thermoelectric refrigeration devices, their preparation methods and applications. Background Technology

[0002] Creating a stable cryogenic environment is crucial for superconducting applications, which place extremely high demands on temperature stability and low vibration. Even minute temperature fluctuations or mechanical vibrations can severely impact system performance and accuracy. Superconductors exhibit their unique physical properties only below their critical transition temperature, which has now been raised to 130 K at ambient pressure and even 160 K under high pressure. However, traditional cryogenic refrigeration technologies, such as pulse tube coolers and Gifford-McMahon (GM) coolers, inevitably generate vibrations during operation due to their complex mechanical structures.

[0003] These vibrations can have adverse effects on the precision applications of superconductors. For example, in nuclear magnetic resonance (NMR) equipment, vibrations can cause signal distortion, thereby affecting image quality and the accuracy of analysis. Therefore, researchers are actively seeking cryogenic cooling technologies that eliminate the need for mechanical parts to reduce vibrations and improve the stability and reliability of the system.

[0004] Thermoelectric cooling technology, as a solid-state solution, utilizes charge carriers within a solid as the working medium. Because it has no moving parts, it achieves vibration-free cooling. This makes it particularly effective in vibration-sensitive applications, such as precision instruments and quantum computing devices. Furthermore, thermoelectric coolers are maintenance-free, demonstrating broad application prospects in environments where conventional maintenance is difficult, such as the deep sea or space.

[0005] However, thermoelectric refrigeration faces dual challenges at both the material and device levels in cryogenic applications. As the temperature decreases, the thermoelectric properties of materials decline sharply, limiting their application potential in deep cryogenic environments.

[0006] Existing thermoelectric refrigeration devices are mainly based on bismuth telluride-based (Bi₂Te₃) materials, which have excellent refrigeration performance within the room temperature range. However, the figure of merit (zT) of their thermoelectric performance deteriorates sharply at low temperatures, and cannot meet the refrigeration requirements in the deep low-temperature field (<170K). Multi-stage refrigerators provide a solution for achieving lower temperatures at the device level, and theoretically, refrigeration temperatures close to 0K can be achieved through infinite cascading. However, under the condition that the hot end is at room temperature, current commercial multi-stage refrigerators can only reach a minimum refrigeration temperature of 170K, which is far from enough to meet the refrigeration requirements for high-temperature superconductivity. Therefore, due to the limitations of thermoelectric materials and device design, the prior art cannot provide lower refrigeration temperatures.

[0007] Chinese patent document CN 118234360 A discloses an n-type lead selenide thermoelectric material, a thermoelectric refrigeration device and a preparation method thereof, wherein the chemical formula of the n-type lead selenide thermoelectric material is Pb 1-x (GaSb) x Se 1-y , wherein 0 < x < 0.002, 0 < y ≤ 0.007. The n-type Pb 0.99875 (GaSb) 0.00125 Se 0.999 material and p-type bismuth telluride material are used as n-type thermoelectric legs and p-type thermoelectric legs respectively, and the n-type and p-type thermoelectric legs are electrically connected in series and thermally connected in parallel by using Pb₉₅ / Sn₅ solder, and then welded on a copper-clad ceramic substrate to fabricate the thermoelectric refrigeration device. When the hot end temperatures are 300K, 323K and 343K, the maximum refrigeration temperature differences obtained are 38K, 46K and 56K respectively. However, the temperature interval for performance optimization of this thermoelectric material is mainly focused on near room temperature and above, and the thermoelectric refrigeration device is also oriented to near room temperature and medium-high temperature applications, without taking into account refrigeration applications below room temperature and in lower temperature regions. Summary of the Invention

[0008] The purpose of the present invention is to provide a Bi 1-x Sb x single crystal material, a thermoelectric refrigeration device, and a preparation method and application thereof. The prepared thermoelectric refrigeration device can provide a lower refrigeration temperature and meet the refrigeration requirements of high-temperature superconductors.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] In one aspect, the present invention provides a Bi 1-x Sb x single crystal material, the Bi 1-x Sb x single crystal material is prepared by zone melting technology, wherein,

[0011] the Bi 1-x Sbx In single-crystal materials, the value of x ranges from 0.1 to 0.15;

[0012] The Bi 1-x Sb x The single-crystal material has a uniform composition and consistent orientation, and the Bi 1-x Sb x The single crystal size of the single crystal material is 1 cm. 3 ~8cm 3 ;

[0013] The Bi 1-x Sb x The single-crystal material is an n-type thermoelectric material.

[0014] Secondly, the present invention also provides the above-mentioned Bi 1-x Sb x The preparation method of single-crystal materials includes the following steps:

[0015] S1, according to Bi 1-x Sb x The stoichiometric ratio of each element in the single crystal material is determined by weighing Bi fragments and Sb fragments as raw material fragments;

[0016] S2. After uniformly mixing the raw material fragments, calcination is carried out under sealed vacuum conditions until a molten state is reached, followed by water quenching to obtain Bi. 1-x Sb x Polycrystalline ingots;

[0017] S3. Bi 1-x Sb x Polycrystalline ingots are cut into small pieces and placed in quartz tubes with a 90° angled tip, then vacuum-sealed.

[0018] S4. The step S3 containing Bi 1-x Sb x The tip of the quartz tube in the polycrystalline ingot is placed in the center of the heating zone within the zone melting furnace, and Bi is obtained through zone melting. 1-x Sb x Single crystal;

[0019] S5, along the Bi obtained in step S3 1-x Sb x Tapping the single crystal along its growth direction yields Bi along the cleavage plane. 1-x Sb x Single crystal materials.

[0020] Preferably, in step S1, the purity of the Bi fragments and Sb fragments is greater than 99.999%.

[0021] Preferably, in step S2, the raw material fragments are uniformly mixed and placed in a quartz tube, the quartz tube is vacuumed and sealed, and the quartz tube is vertically suspended in the center of the tube furnace.

[0022] Preferably, in step S2, the raw material fragments are kept at a temperature of 893–1093 K for 4–6 hours until they reach a molten state, and more preferably, they are kept at a temperature of 993 K for 5 hours until they reach a molten state.

[0023] Preferably, in step S3, Bi is... 1-x Sb x Polycrystalline ingots are cut into small pieces, the size of which is 3mm to 5mm.

[0024] The vacuum sealing in step S3 of this invention is to prevent the quartz tube from being exposed to Bi. 1-x Sb x The material expands in volume as it slowly solidifies, causing the quartz tube to rupture.

[0025] Preferably, in step S4, the center temperature of the heating zone is controlled to be 573K to 773K, and the quartz tube is slowly lowered at a speed of 0.8-1.5μm / s until the Bi... 1-x Sb x The top of the polycrystalline ingot is lowered below the melting zone, and it is melted once or multiple times.

[0026] Preferably, in step S4, the size of the heating zone of the zone melting furnace is 5-10 mm.

[0027] Preferably, in step S5, a sharp object is used to strike along the crystal growth direction, the sharp object including a metal needle tip or a knife.

[0028] Thirdly, the present invention also provides a thermoelectric cooling device, comprising the aforementioned Bi 1-x Sb x Single crystal materials.

[0029] Preferably, the thermoelectric cooling device includes Bi 1-x Sb x Basic single-stage thermoelectric refrigeration device or Bi 1-x Sb x The Bi multi-stage thermoelectric cooling device 1-x Sb x Multi-stage thermoelectric refrigeration devices are made of Bi 1-x Sb x Basic single-stage thermoelectric refrigeration devices are obtained by cascading assembly using solder.

[0030] The Bi 1-x Sb x Basic single-stage thermoelectric refrigeration devices include Bi1-x Sb x Base single-pair cooling module or Bi 1-x Sb x Kido cooling module, the Bi 1-x Sb x Kido cooling module is made of Bi 1-x Sb x The basic cooling module is assembled using solder.

[0031] Fourthly, the present invention also provides a method for preparing the above-mentioned thermoelectric refrigeration device, comprising the following steps:

[0032] a. Change Bi 1-x Sb x BiSbTe material was cut to obtain Bi 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs;

[0033] b. The Bi obtained in step a 1-x Sb x The monocrystalline thermoelectric legs and BiSbTe thermoelectric legs are successively subjected to alkaline washing, water washing, acid washing, and water washing to remove oil stains;

[0034] c. The Bi obtained in step c for removing oil stains 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs were electroplated to obtain BiSbTe thermoelectric legs with Ni electrode layers. 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs;

[0035] d. The Bi with Ni electrode layer obtained in step c 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs are made by using Bi 0.58 Sn 0.42 Solder is applied to an aluminum nitride ceramic plate with a Cu coating to obtain the Bi. 1-x Sb x Base single-pair cooling module;

[0036] e. The Bi obtained in step d 1-x Sb x The basic single-pair cooling module is assembled and cascaded using solder to obtain Bi. 1-x Sb x Multistage thermoelectric refrigeration devices.

[0037] Preferably, in step a, the BiSbTe material is a p-type thermoelectric material.

[0038] More preferably, in step a, the BiSbTe material includes a p-type Bi2Te3 thermoelectric material.

[0039] Preferably, in step a, the Bi 1-x Sb x The dimensions of the single-crystal thermoelectric leg are (0.4~0.8)*(1.0~1.6)*(5~15)mm. 3 .

[0040] Preferably, in step a, the dimensions of the BiSbTe thermoelectric leg are (1.0~1.5)*(1.0~1.5)*(5~15) mm. 3 .

[0041] Preferably, in step a, the cutting is performed using diamond wire.

[0042] Preferably, in step b, the alkaline washing refers to cleaning and removing oil stains in an alkaline solution containing 60-80 g / L NaOH, 20-40 g / L Na2CO3, 10-20 g / L Na3PO4·12H2O and 4-8 g / L Na2SiO3.

[0043] More preferably, in step b, the alkaline washing refers to cleaning and removing oil stains in an alkaline solution containing 70 g / L NaOH, 30 g / L Na2CO3, 15 g / L Na3PO4·12H2O and 6 g / L Na2SiO3.

[0044] Preferably, in step b, the acid washing refers to heavy washing with hydrochloric acid at a concentration of 36wt% to 38wt% to remove residual alkali.

[0045] Preferably, in step c, the electroplating treatment refers to plating in an environment containing 200–280 g / L NiSO4·7H2O, 30–40 g / L H3BO3, 5–15 g / L NaCl, 60–80 g / L Na2SO4, 60–80 g / L MgSO4, and 0.9–1.0 g / L C. 12 H 25 SO4Na electroplating solution at 35–55℃ and 1–2.4 A / cm 2 Electroplating at a current density of 6–15 min.

[0046] More preferably, in step c, the electroplating treatment refers to plating in an environment containing 240 g / L NiSO4·7H2O, 35 g / L H3BO3, 10 g / L NaCl, 70 g / L Na2SO4, 70 g / L MgSO4, and 0.985 g / L C. 12 H 25 SO4Na electroplating solution at 45℃ and 1.8 A / cm2 Electroplating at the current density for 10 minutes.

[0047] In this invention, Ni (nickel) is used as the electrode material in the electroplating process. The Ni electrode layer can effectively reduce contact resistance, prevent element diffusion, and ensure good contact between the thermoelectric leg and the solder.

[0048] Preferably, in step d, the Bi with the Ni electrode layer is... 1-x Sb x Before the single-crystal thermoelectric legs and BiSbTe thermoelectric legs are welded to the aluminum nitride ceramic plate with a Cu coating, the BiSbTe with Ni electrode layer also needs to be processed. 1-x Sb x The sides of the single-crystal thermoelectric leg and the BiSbTe thermoelectric leg are polished to remove the Ni electrode layer plated on their sides.

[0049] Preferably, in step d, the Bi 0.58 Sn 0.42 The melting point of the solder is 120℃~145℃, and more preferably 138℃.

[0050] Preferably, in step e, the melting point of the solder is 35-55°C, and more preferably 45°C.

[0051] More preferably, in step e, the solder is an InSnBi alloy.

[0052] Fifthly, the present invention also provides an application of the above-mentioned thermoelectric cooling device, which is used for low-temperature cooling of high-temperature superconductors.

[0053] Preferably, the thermoelectric cooling device is applied to the cooling of the YBa2Cu3O7 superconductor to achieve stable operation in the superconducting state.

[0054] This invention provides a Bi 1-x Sb x This invention relates to single-crystal materials, thermoelectric cooling devices, their fabrication methods, and applications, serving the cooling needs of high-temperature superconductors. At the materials level, a high-performance Bi-Sb alloy is used to replace the traditional n-type Bi₂Te₃ material, exhibiting optimized cooling performance at low temperatures below 170K. At the device level, the geometric design of the multi-stage cooling device is optimized, improving cascade efficiency and achieving a cooling temperature as low as 130K. Furthermore, this invention applies the cooling device to the cooling of YBa₂Cu₃O₇ high-temperature superconductors, demonstrating the application potential of thermoelectric cooling devices in the field of high-temperature superconductivity.

[0055] This invention prepares a Bi-Sb-based high-performance cryogenic refrigeration material that can be reliably applied to cryogenic refrigeration. The Bi of this invention... 1-x Sbx Single-crystal materials have a high electrical power factor S 2 σ, where S is the Seebeck coefficient and σ is the material's electrical conductivity. Simultaneously, the solid solution of Sb reduces its lattice thermal conductivity, thus comprehensively improving the material's thermoelectric properties. Due to the large segregation coefficient of solute Sb in the Bi matrix, Sb composition inhomogeneity is easily caused, resulting in poor repeatability of thermoelectric properties. Compared with traditional smelted or sintered polycrystalline materials, single-crystal Bi... 1-x Sb x The material exhibits superior thermoelectric properties. Based on this, the present invention utilizes zone melting combined with controlled growth rate and temperature gradient to reduce the thermodynamic equilibrium driving force promoting solute element diffusion, thus developing a method for preparing Bi with consistent orientation and uniform composition. 1-x Sb x Methods for single-crystal materials.

[0056] Based on the fact that the lowest cooling temperature of commercial Bi₂Te₃-based multistage refrigeration devices is only 170K, this invention aims to develop Bi₂Te₃-based multistage refrigeration devices for cryogenic applications. 1-x Sb x Bi-Sb-based refrigeration devices can replace Bi2Te3 materials to further cool to even lower temperatures. Preferably, the two-stage Bi-Sb-based refrigeration device is used in conjunction with commercially available Bi... 2-x Sb x Cascading Te3-based cooling devices maximizes cooling capacity across the entire temperature range.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] (1) This invention prepares intrinsic Bi with uniform composition and consistent orientation by zone melting technology. 1-x Sb x Single-crystal materials, without the need for other doping elements, avoid fluctuations in thermoelectric properties caused by compositional inhomogeneity. Compared to traditional polycrystalline materials, the Bi of this invention... 1-x Sb x Single-crystal materials have significant advantages in terms of anisotropy, exhibiting more stable and reliable thermoelectric properties.

[0059] (2) This invention uses Bi 1-x Sb x The alloy replaces the traditional n-type Bi2Te3-based material. Due to the superior thermoelectric properties of this material in the low-temperature region, the thermoelectric cooling device made by this material exhibits better thermoelectric performance in low-temperature environments below 170K, with a cooling temperature difference of about 1.7 times that of commercial Bi2Te3-based devices at the same temperature.

[0060] (3) Through multi-stage device geometry design, this invention optimizes the cascading efficiency of the devices, enabling the cooling devices to achieve a minimum cooling temperature of 130K. This technological breakthrough overcomes the temperature limitations of traditional Bi2Te3-based cooling devices and significantly improves low-temperature cooling capabilities.

[0061] (4) The refrigeration device of the present invention has been successfully applied to the low-temperature refrigeration of YBa2Cu3O7 high-temperature superconductor, demonstrating the huge application potential of thermoelectric refrigeration technology in the field of high-temperature superconductivity, and providing technical support for the further development of superconducting technology in the future. Attached Figure Description

[0062] Figure 1 Bi in Example 1 0.85 Sb 0.15 Phase characterization and microscopic morphology of single crystals;

[0063] Figure 2 Bi in Example 1 0.85 Sb 0.15 Electrical and thermal properties of single crystals at 80-300K and their figure of merit;

[0064] Figure 3 Example 2 contains Bi 0.85 Sb 0.15 -Interfacial contact resistance and morphology of a single-stage thermoelectric refrigeration device in a basic single-pair refrigeration module.

[0065] Figure 4 Examples 2 and 3 contain Bi 0.85 Sb 0.15 - The resistance values ​​and predicted internal resistance diagrams of single-stage thermoelectric refrigeration devices with single-pair and three-pair refrigeration modules measured by AC method;

[0066] Figure 5 This is a graph showing the temperature difference over time for a single-stage thermoelectric refrigeration device containing a single pair of refrigeration modules in Example 2 under hot-end conditions of 280-270K.

[0067] Figure 6 The figure shows the cooling power and cooling efficiency of the single-stage thermoelectric refrigeration device containing a single pair of refrigeration modules in Example 2 under the hot end condition of 80-180K.

[0068] Figure 7 This is a graph showing the temperature difference over time for a single-stage thermoelectric refrigeration device containing three pairs of refrigeration modules in Example 3 under a 270K hot end condition.

[0069] Figure 8 Bi in Example 4 is YBa2Cu3O7 1-x Sb x A graph showing the superconducting transition under cooling conditions of a two-stage thermoelectric refrigeration device;

[0070] Figure 9 This is a graph showing the lowest cooling temperature of the six-stage thermoelectric refrigeration device in Example 5 at different hot-end temperatures;

[0071] Figure 10 This is a structural diagram of the six-stage thermoelectric refrigeration device in Example 5. Detailed Implementation

[0072] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0073] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0074] Example 1

[0075] A kind of Bi 0.85 Sb 0.15 The specific preparation process of single-crystal materials is as follows:

[0076] (1) Based on the stoichiometric ratio Bi 0.85 Sb 0.15 High-purity Bi fragments and Sb fragments were weighed as raw materials.

[0077] (2) The raw material fragments were uniformly mixed and placed in a quartz tube, which was then vacuum-sealed. The quartz tube was vertically suspended in the center of a tube furnace. It was held at 993 K for 5 hours to reach a molten state, followed by rapid water quenching to obtain Bi. 0.85 Sb 0.15 Polycrystalline ingots.

[0078] (3) Remove the polycrystalline ingot from the quartz tube and cut it into small pieces. Place these pieces into a quartz tube with its tip at a 90° angle and reseal it under vacuum. This operation is to prevent the quartz tube from being sealed in Bi. 0.85 Sb 0.15 The material expands in volume as it slowly solidifies, causing the quartz tube to rupture.

[0079] (4) Place the polycrystalline ingot from step (3) into a zone melting furnace with a heating zone of 5-10 mm, place the tip of the quartz tube in the center of the heating zone, control the temperature of the center of the heating zone to 673 K, and slowly lower the quartz tube at a speed of 0.8 μm / s until the top of the ingot is lowered below the melting zone.

[0080] (5) Take Bi from step (4) 0.85 Sb0.15 The single crystal was taken out of the quartz tube and struck along the crystal growth direction with a sharp object to obtain Bi along the cleavage plane. 0.85 Sb 0.15 Single-crystal materials.

[0081] In this embodiment, for the Bi obtained by growth 0.85 Sb 0.15 Single-crystal ingots were used, and in-plane single-crystal samples from three locations along the growth direction were taken for phase and microstructure characterization. The results are as follows: Figure 1 Phase characterization, such as Figure 1 As shown in a-b, the c-axis lattice constant calculated from its XRD diffraction peaks is highly consistent with the predicted value of Vegard's law, and the deviation among the three single-crystal samples is less than 1%, indicating that the grown single crystals have compositional homogeneity. Furthermore, as... Figure 1 As shown in Figure c, scanning electron microscopy (SEM) images further confirm that no Sb segregation occurred in the crystal. The Bi... 0.85 Sb 0.15 The uniformity of crystal composition ensures the integration of subsequent cooling devices.

[0082] Figure 2 a to e represent the low-temperature thermoelectric properties of samples from three different locations, demonstrating excellent repeatability. Within the temperature range of 100-200 K, the in-plane Bi... 0.85 Sb 0.15 The average zT value (thermoelectric figure of merit) of the single crystal is 0.37, which is superior to that of commercial n-type Bi2Te3 materials. The thermal stability of its thermoelectric properties was evaluated by three thermal cycling tests, and the results showed that its thermoelectric properties hardly degraded, demonstrating its excellent durability.

[0083] Example 2

[0084] A single-stage thermoelectric refrigeration device containing a single pair of refrigeration modules for high-temperature superconductivity is implemented as follows:

[0085] (1) The in-plane direction Bi obtained in Example 1 0.85 Sb 0.15 Single-crystal materials and commercial BiSbTe materials were cut to the required dimensions using a diamond wire cutter. The p-type Bi₂Te₃ thermoelectric leg dimensions were 1.3*1.3*10mm. 3 n-type Bi 0.85 Sb 0.15 The dimensions of the single-crystal thermoelectric leg are 0.6*1.3*10mm. 3 .

[0086] (2) The p-type Bi2Te3 thermoelectric leg and n-type Bi obtained in step (1) 0.85 Sb 0.15The single-crystal thermoelectric leg was placed in an alkaline solution containing NaOH (70g / L), Na2CO3 (30g / L), Na3PO4·12H2O (15g / L) and Na2SiO3 (6g / L) to clean the residual oil from the cutting process.

[0087] (3) Rinse the two thermoelectric legs after alkaline washing with pure water, and then remove the residual alkaline washing solution in 36% to 38% hydrochloric acid.

[0088] (4) Rinse the two thermoelectric legs obtained in step (3) with pure water, and then rinse them with a solution containing NiSO4·7H2O (240 g / L), H3BO3 (35 g / L), NaCl (10 g / L), Na2SO4 (70 g / L), MgSO4 (70 g / L) and C. 12 H 25 SO4Na (0.985 g / L) electroplating solution at 45℃ and 1.8 A / cm 2 Electroplating was performed at a current density for 10 minutes. The thermoelectric leg was then electroplated to prepare a solderable electrode.

[0089] (5) Polish the sides of the two types of thermoelectric legs with Ni electrode layers obtained in step (4) to remove the electrode layers plated on the sides, and obtain the p-type Bi2Te3 thermoelectric leg and n-type Bi2Te3 thermoelectric leg of the required size. 0.85 Sb 0.15 Single-crystal thermoelectric legs. The two types of treated thermoelectric legs were assembled onto an aluminum nitride (AlN) ceramic plate with a Cu coating, and Bi with a melting point of 138℃ was used. 0.58 Sn 0.42 Solder is used to assemble modules to obtain a single-stage thermoelectric refrigeration device containing a single pair of refrigeration modules.

[0090] The n-type Bi obtained in Example 1 0.85 Sb 0.15 After combining in-plane single crystals with commercial p-type Bi₂Te₃ to form a single module, the device performance was examined, such as... Figure 2 As shown in d, its thermoelectric figure of merit is significantly better than that of commercial Bi2Te3-based devices below 180K.

[0091] Figure 3 This describes the interface contact resistance and diffusion of this single pair of cooling modules. For example, Figure 3 As shown in a and 3c, the average contact resistivity of the solder / Ni electrode layer / thermoelectric material interface is approximately 28 μΩ·cm for p-type Bi₂Te₃. 2 n-type Bi 0.85 Sb 0.15 In-plane single crystal 5.6 μΩ·cm 2 Furthermore, such as Figure 3As shown in b and 3d, scanning electron microscope (SEM) images show that the Ni electrode layer effectively prevents elemental diffusion between the solder and the thermoelectric material. Figure 4 The total resistance of the single pair of cooling modules and the internal resistance predicted based on material properties show that the contact interface accounts for only about 5% of the total resistance of the device, thus ensuring minimal performance degradation.

[0092] The single-stage thermoelectric refrigeration device containing a single pair of refrigeration modules developed in this embodiment 2 exhibits the following refrigeration performance in the range of 80–270 K: Figure 5 As shown. In optimizing the current (I = I...) opt Maximum refrigeration temperature difference (ΔT) under the condition max This invention achieves approximately 85% predictive performance. At a hot-end temperature of 179K, the ΔT achieved in this invention... max The ΔT is approximately 21 K, compared to the previously reported ~12 K for Bi2Te3 devices at the same temperature. max 80% higher. Figure 6 The diagram shows the cooling power and efficiency of the device under hot-end conditions of 80–180 K, where it exhibits approximately 3.6 kW / m² at 180 K. 2 The low-temperature refrigeration capacity demonstrates its potential for refrigeration at low temperatures.

[0093] Example 3

[0094] A single-stage thermoelectric refrigeration device containing three pairs of refrigeration modules for high-temperature superconductivity is implemented as follows:

[0095] (1) The in-plane direction Bi obtained in Example 1 0.85 Sb 0.15 Single-crystal materials and commercial BiSbTe materials were cut to the required dimensions using a diamond wire cutter. The P-type Bi₂Te₃ thermoelectric leg dimensions were 1.5*1.5*7mm. 3 n-type Bi 0.85 Sb 0.15 The dimensions of the single-crystal thermoelectric leg are 0.7*1.3*7mm. 3 .

[0096] (2) The two thermoelectric legs obtained in step (1) are placed in an alkaline solution containing NaOH (70g / L), Na2CO3 (30g / L), Na3PO4·12H2O (15g / L) and Na2SiO3 (6g / L) to clean the residual oil stains from the cutting process.

[0097] (3) Rinse the thermoelectric leg after alkaline washing with pure water, and then remove the residual alkaline washing solution in 36% to 38% hydrochloric acid.

[0098] (4) Rinse the thermoelectric leg obtained in step (3) with pure water, and then rinse it with a solution containing NiSO4·7H2O (240 g / L), H3BO3 (35 g / L), NaCl (10 g / L), Na2SO4 (70 g / L), MgSO4 (70 g / L) and C. 12 H 25 SO4Na (0.985 g / L) electroplating solution at 45℃ and 1.8 A / cm 2 Electroplating was performed at a current density for 10 minutes. The thermoelectric leg was then electroplated to prepare a solderable electrode.

[0099] (5) Polish the sides of the two types of thermoelectric legs with Ni electrode layers obtained in step (4) to remove the electrode layers plated on the sides, and obtain the p-type Bi2Te3 thermoelectric leg and n-type Bi2Te3 thermoelectric leg of the required size. 0.85 Sb 0.15 Single-crystal thermoelectric legs. The two types of treated thermoelectric legs were assembled onto an aluminum nitride (AlN) ceramic plate with a Cu coating, and Bi with a melting point of 138℃ was used. 0.58 Sn 0.42 Solder is used to assemble modules to obtain a single pair of cooling modules. The three pairs of single cooling modules are then assembled using an InSnBi alloy with a melting point of 45℃ to obtain a single-stage thermoelectric cooling device containing three pairs of cooling modules.

[0100] Figure 7 The cooling performance of the single-stage thermoelectric refrigeration device with three pairs of cooling modules in this embodiment 3 at a hot end temperature of 270K shows better repeatability compared to the single-stage thermoelectric refrigeration device with a single pair of cooling modules, indicating that the method and device proposed in this embodiment have reliable repeated application.

[0101] Example 4

[0102] A multi-stage thermoelectric refrigeration device for high-temperature superconductivity is implemented as follows:

[0103] The single-stage thermoelectric refrigeration devices containing a single pair of refrigeration modules and the single-stage thermoelectric refrigeration devices containing three pairs of refrigeration modules obtained in Examples 2 and 3 respectively were cascaded and assembled using an InSnBi alloy with a melting point of 45°C to obtain Bi 1-x Sb x Two-stage refrigeration device.

[0104] In Example 4, a verification experiment was conducted to evaluate the feasibility of using a thermoelectric cooling device for cooling high-temperature superconductors. A YBa2Cu3O7 thin film with a superconducting transition temperature of approximately 91-91.4 K was fixed at the cold end of the thermoelectric cooler, as shown below. Figure 8As shown, the two-stage low-temperature thermoelectric cooler developed in this invention successfully cooled the YBa2Cu3O7 thin film from 100K to 91K, thereby realizing its transformation from the normal state to the superconducting state, and confirming the potential of the low-temperature thermoelectric device prepared in this embodiment for superconducting cooling.

[0105] Example 5

[0106] For each operating temperature range, high-performance materials are selected to construct multi-stage thermoelectric cooling devices. The Bi material prepared in Example 4 is used in this process. 1-x Sb x Using a two-stage thermally based refrigeration device as the low-temperature refrigeration device, and Ferrotec's commercial Bi2Te3-based four-stage refrigeration device (2040 / 153 / 080MN / CO2) as the room-temperature refrigeration device, a heterogeneous six-stage refrigeration device is obtained, the structure of which is as follows: Figure 10 As shown.

[0107] Figure 9 This reflects the cooling temperature of the six-stage device. The overall cooling performance is maximized when each stage operates under its optimal current conditions. Based on this, the cryogenic thermoelectric cooler in this embodiment features a personalized optimization design for the operating current of each stage. By optimizing the operating conditions of the two-stage cryogenic cooler, this embodiment achieves a record-breaking minimum cooling temperature of approximately 130K at a hot-end temperature of 300K. This cooling performance also demonstrates stability after three temperature cycling cycles.

[0108] In summary, the technical solution of the present invention has the following advantages:

[0109] I. This invention successfully prepared Bi with uniform composition and orientation using zone melting technology. 1-x Sb x Single-crystal materials, produced without the need for doping, avoid the resulting fluctuations in thermoelectric properties. Compared to conventional polycrystalline materials, these single-crystal materials exhibit superior anisotropy, providing more stable and reliable thermoelectric performance, which is crucial for ensuring the high efficiency and long-term operational stability of cryogenic refrigeration devices.

[0110] II. This invention uses Bi 1-x Sb x This alloy, as a novel n-type material, replaces the traditional n-type Bi₂Te₃ material. Benefiting from Bi... 1-x Sb x Exhibiting superior thermoelectric performance in a temperature range below 170K, the cooling device significantly enhances the cooling effect in low-temperature environments, with a cooling temperature difference approximately 1.7 times that of Bi2Te3-based cooling devices on the market, thereby greatly improving the efficiency of low-temperature cooling.

[0111] Third, this invention also achieves a technological breakthrough, successfully reducing the cooling temperature to a minimum of 130K. This achievement breaks the temperature limitations of traditional Bi2Te3-based cooling devices and has been successfully applied to the cooling process of YBa2Cu3O7 high-temperature superconductors. This not only confirms the broad application prospects of thermoelectric cooling devices in the field of high-temperature superconductivity technology, but also signifies a further expansion of their application potential in this field.

[0112] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A thermoelectric cooling device, characterized in that, Including Bi 1-x Sb x Basic single-stage thermoelectric refrigeration device or Bi 1-x Sb x The Bi multi-stage thermoelectric cooling device 1-x Sb x Multi-stage thermoelectric refrigeration devices are made of Bi 1-x Sb x Basic single-stage thermoelectric refrigeration devices are obtained by cascading assembly using solder. The Bi 1-x Sb x Basic single-stage thermoelectric refrigeration devices include Bi 1-x Sb x Base single-pair cooling module or Bi 1-x Sb x Kido cooling module, the Bi 1-x Sb x Kido cooling module is made of Bi 1-x Sb x The basic single-pair cooling module is assembled using solder, wherein the Bi 1-x Sb x The base single-pair cooling module includes the Bi mentioned above. 1-x Sb x Single crystal materials; The method for preparing the thermoelectric refrigeration device includes the following steps: a. Change Bi 1-x Sb x BiSbTe material was cut to obtain Bi 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs; b. The Bi obtained in step a 1-x Sb x The monocrystalline thermoelectric legs and BiSbTe thermoelectric legs are successively subjected to alkaline washing, water washing, acid washing, and water washing to remove oil stains; c. The Bi obtained in step c for removing oil stains 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs were electroplated to obtain BiSbTe thermoelectric legs with Ni electrode layers. 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs; d. The Bi with Ni electrode layer obtained in step c 1-x Sb x Single-crystal thermoelectric legs and BiSbTe thermoelectric legs are made by using Bi 0.58 Sn 0.42 Solder is applied to an aluminum nitride ceramic plate with a Cu coating to obtain the Bi. 1-x Sb x Base single-pair cooling module; e. The Bi obtained in step d 1-x Sb x The basic single-pair cooling module is assembled and cascaded using solder to obtain Bi. 1-x Sb x Multistage thermoelectric refrigeration devices; The Bi 1-x Sb x Single-crystal materials are prepared through zone melting technology, in which... The Bi 1-x Sb x In single-crystal materials, the value of x ranges from 0.1 to 0.15; The Bi 1-x Sb x The single-crystal material has a uniform composition and consistent orientation, and the Bi 1-x Sb x The single crystal size of the single crystal material is 1 cm. 3 ~8 cm 3 ; The Bi 1-x Sb x Single-crystal materials are n-type thermoelectric materials; In step e, the melting point of the solder is 35~55℃, and the solder is an InSnBi alloy; The Bi 1-x Sb x The preparation method of single crystal materials includes the following steps: S1, according to Bi 1-x Sb x The stoichiometric ratio of each element in the single crystal material is determined by weighing Bi fragments and Sb fragments as raw material fragments; S2. After uniformly mixing the raw material fragments, calcination is carried out under sealed vacuum conditions until a molten state is reached, followed by water quenching to obtain Bi. 1-x Sb x Polycrystalline ingots; S3. Bi 1-x Sb x Polycrystalline ingots are cut into small pieces and placed in quartz tubes with a 90° angled tip, then vacuum-sealed. S4. The step S3 containing Bi 1-x Sb x The tip of the quartz tube in the polycrystalline ingot is placed in the center of the heating zone within the zone melting furnace, and Bi is obtained through zone melting. 1-x Sb x Single crystal; S5, along the Bi obtained in step S3 1-x Sb x Tapping the single crystal along its growth direction yields Bi along the cleavage plane. 1-x Sb x Single crystal materials; In step S4, the center temperature of the heating zone is controlled at 573K~773K, and the quartz tube is slowly lowered at a speed of 0.8-1.5 μm / s until the Bi... 1-x Sb x The top of the polycrystalline ingot is lowered below the melting zone, and it is melted once or multiple times.

2. The thermoelectric cooling device according to claim 1, characterized in that, In step S2, the... After the raw material fragments are evenly mixed, they are placed in a quartz tube, which is then vacuumed and sealed. The quartz tube is then vertically suspended in the center of a tube furnace. The raw material fragments are kept at a temperature of 893~1093 K for 4~6 hours until they reach a molten state.

3. The thermoelectric cooling device according to claim 1, characterized in that, In step b, the alkaline washing refers to cleaning and removing oil stains in an alkaline solution containing 60-80 g / L NaOH, 20-40 g / L Na2CO3, 10-20 g / L Na3PO4·12H2O and 4-8 g / L Na2SiO3. The pickling refers to the process of washing with hydrochloric acid at a concentration of 36 wt% to 38 wt% to remove residual alkali.

4. The thermoelectric cooling device according to claim 1, characterized in that, In step c, the electroplating treatment refers to plating in an environment containing 200-280 g / L NiSO4·7H2O, 30-40 g / L H3BO3, 5-15 g / L NaCl, 60-80 g / L Na2SO4, 60-80 g / L MgSO4, and 0.9-1.0 g / L C. 12 H 25 SO4Na electroplating solution at 35~55℃ and 1~2.4A / cm 2 Electroplating at a current density of 6~15 min.

5. An application of the thermoelectric cooling device as described in any one of claims 1 to 4, characterized in that, The thermoelectric cooling device is suitable for low-temperature cooling of high-temperature superconductors.

Images