An n-type lead selenide thermoelectric material and thermoelectric refrigeration device and method of manufacture

Abstract

The application discloses an n-type lead selenide thermoelectric material and a thermoelectric refrigeration device and a preparation method. 1‑x (GaSb) x Se 1‑y , wherein 0.0001<=x<0.002, 0.0001<=y<=0.007. The prepared Pb 0.99875 (GaSb) 0.00125 Se 0.999 The thermoelectric figure of merit of the material is about 0.6 at room temperature. The thermoelectric refrigeration device made of the n-type Pb 0.99875 (GaSb) 0.00125 Se 0.999 Material and p-type bismuth telluride material, when the temperature of the hot end is 300K, 323K and 343K, the maximum refrigeration temperature difference obtained is 38K, 46K and 56K respectively.

Description

Technical Field

[0001] This invention belongs to the technical field of thermoelectric materials and thermoelectric refrigeration devices, specifically relating to an n-type lead selenide thermoelectric material, a thermoelectric refrigeration device, and a preparation method thereof. Background Technology

[0002] Thermoelectric materials are environmentally friendly functional materials that can directly convert heat energy into electrical energy and vice versa, and can be used for refrigeration using the Peltier effect. Thermoelectric refrigeration systems have unique advantages such as small size, no noise, high reliability, fast response, and long lifespan. They are widely used in medical devices, cryogenic instruments, electronic components, 5G optical communication modules, infrared detection, and other fields.

[0003] Currently, bismuth telluride is the only commercially available thermoelectric cooling material. The thermoelectric performance of n-type bismuth telluride is often lower than that of p-type bismuth telluride. For n-type bismuth telluride thermoelectric materials, single crystals are often grown using zone melting. Because bismuth telluride crystals have a layered structure, with adjacent Te atomic layers interacting through van der Waals forces, directionally grown single crystals are prone to dissociation along the growth direction, resulting in poor mechanical properties, making them difficult to process and unable to meet the requirements for fabricating miniature cooling devices. Therefore, much research has focused on using powder sintering to prepare dense polycrystalline bulk materials, thereby improving the material's mechanical properties. Simultaneously, hot deformation processes are combined to improve the thermoelectric performance. However, the synthesis process is quite cumbersome, often requiring multiple hot deformation treatments, making large-scale production difficult. Furthermore, the carrier concentration of n-type bismuth telluride is highly sensitive to the synthesis process, accompanied by a donor-like effect, resulting in low reproducibility; Te is scarce and expensive in the Earth's crust, all of which are detrimental to the construction of thermoelectric cooling devices. Therefore, finding new thermoelectric materials with high mechanical properties, low cost, and high performance near room temperature is an urgent problem to be solved. Summary of the Invention

[0004] To address the above problems, this invention provides an n-type lead selenide thermoelectric material, a thermoelectric cooling device, and a preparation method. The n-type lead selenide thermoelectric material prepared by this method exhibits a thermoelectric figure of merit (FG) of 300 K. ZT The value is approximately 0.6, which is the value of n-type Pb obtained from Example 1. 0.99875 (GaSb) 0.00125 Se 0.999 Thermoelectric refrigeration devices constructed from thermoelectric materials and p-type bismuth telluride thermoelectric materials can achieve a large cooling temperature difference.

[0005] The present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides an n-type lead selenide thermoelectric material for thermoelectric refrigeration, wherein the chemical formula of the n-type lead selenide thermoelectric material is Pb. 1-x (GaSb) x Se1-y Where 0.0001≤x<0.002, 0.0001≤y≤0.007. For example, x can be 0.0001, 0.0002, 0.0003, 0.0004, 0.0005, 0.0006, 0.0007, 0.0008, 0.0009, 0.001, 0.0011, 0.0012, 0.0013, 0.0014, 0.0015, 0.0016, 0.0017, 0.0018, or 0.0019. For example, y is 0.0001, 0.0003, 0.0005, 0.0007, 0.0009, 0.0011, 0.0013, 0.0015, 0.0017, 0.0019, 0.0021, 0.0023, 0.0025, 0.0027, 0.0029, 0.0031, 0.0033, 0 0.0035, 0.0037, 0.0039, 0.0041, 0.0043, 0.0045, 0.0047, 0.0049, 0.0051, 0.0053, 0.0055, 0.0057, 0.0059, 0.0061, 0.0063, 0.0065, 0.0067 or 0.0069.

[0007] Preferably, x = 0.00125.

[0008] Preferably, 0.001≤y≤0.005.

[0009] Preferably, the n-type lead selenide thermoelectric material is Pb. 0.99875 (GaSb) 0.00125 Se 0.999 .

[0010] Secondly, the present invention provides a method for preparing an n-type lead selenide thermoelectric material for thermoelectric refrigeration, specifically comprising the following steps:

[0011] S1. Prepare raw materials: Pb strips, Ga granules, Sb granules, and Se granules;

[0012] S2. Weigh out the elements Ga and Sb according to the atomic ratio, pour them into a dried quartz tube, evacuate the tube and seal it with an oxyhydrogen flame, and react at high temperature to obtain the GaSb compound.

[0013] S3. Weigh out elemental Pb, Se, and compound GaSb according to their atomic ratios, and pour them into a dried quartz tube. After evacuating the tube, seal it with an oxyhydrogen flame and react at high temperature to obtain Pb. 1-x (GaSb) x Se 1-y Compounds.

[0014] Preferably, in step S2, the specific reaction process is as follows: heating from room temperature to 700℃, 750℃, 800℃, 850℃ or 900℃ for 8-12 hours, and holding at this temperature for 4 h, 5 h, 6 h, 7 h or 8 h, and then cooling to room temperature for 10 h, 11 h, 12 h, 13 h or 14 h to obtain the GaSb compound; preferably, the heating rate is 50℃ / h, 55℃ / h, 60℃ / h, 70℃ / h, 80℃ / h, 90℃ / h or 100℃ / h; preferably, the cooling rate is 50℃ / h, 55℃ / h, 60℃ / h, 70℃ / h, 80℃ / h, 90℃ / h or 100℃ / h; preferably, the specific reaction process is as follows: heating to 800℃ for 10 hours, holding at 800℃ for 5 hours, and then cooling to room temperature for 12 hours to obtain the GaSb compound.

[0015] Preferably, in step S3, the specific reaction process is as follows: the temperature is raised from room temperature to 1100℃, 1125℃, 1150℃, 1175℃, 1200℃, 1225℃, or 1250℃ over 10-14 hours, and held at this temperature for 5 h, 6 h, 7 h, or 8 h, followed by water quenching to obtain Pb. 1-x (GaSb) x Se 1-y The compound; preferably, the specific reaction process is as follows: raising the temperature to 1200℃ for 12 hours, holding at 1200℃ for 6 hours, and then water quenching to obtain Pb. 1-x (GaSb) x Se 1-y The compound; preferably, the heating rate is 80℃ / h, 90℃ / h, 100℃ / h, 110℃ / h or 120℃ / h.

[0016] Preferably, in step S2, the specific process of the high-temperature reaction is as follows: the temperature is raised to 800°C for 10 hours, kept at 800°C for 5 hours, and then cooled to room temperature for 12 hours to obtain the GaSb compound.

[0017] Preferably, in step S3, the specific process of the high-temperature reaction is as follows: the temperature is raised to 1200℃ over 12 hours, held at 1200℃ for 6 hours, and then water-quenched to obtain Pb. 1-x (GaSb) x Se 1-y Compounds.

[0018] Thirdly, the present invention provides a lead selenide-based thermoelectric refrigeration device.

[0019] Preferably, the thermoelectric cooling device is made of n-type Pb 0.99875 (GaSb) 0.00125 Se 0.999 It consists of thermoelectric materials and p-type bismuth telluride thermoelectric materials.

[0020] Fourthly, the present invention provides a method for preparing the above-mentioned thermoelectric refrigeration device, comprising the following steps:

[0021] The obtained n-type Pb 1-x (GaSb) x Se 1-y The thermoelectric material and p-type bismuth telluride thermoelectric material are cut to serve as n-type and p-type thermoelectric legs, respectively. The n-type and p-type thermoelectric legs are then soldered onto a copper-clad ceramic substrate in an electrically connected series and thermally parallel manner using Pb95 / Sn5 solder to fabricate a thermoelectric cooling device.

[0022] Preferably, the n-type Pb 1-x (GaSb) x Se 1-y The thermoelectric material is Pb 0.99875 (GaSb) 0.00125 Se 0.999 .

[0023] The above technical solution has the following advantages:

[0024] This experiment uses inexpensive lead and selenium as raw materials, saving costs in constructing thermoelectric refrigeration devices from the outset. The prepared n-type lead selenide thermoelectric material exhibits high room-temperature thermoelectric performance, which helps to improve the maximum cooling temperature difference of the thermoelectric refrigeration device. The prepared n-type bismuth telluride thermoelectric material has good mechanical properties, facilitating processing. The prepared Pb... 0.99875 (GaSb) 0.00125 Se 0.999 The material has a room-temperature thermoelectric figure of merit of around 0.6. It is composed of n-type Pb. 0.99875 (GaSb) 0.00125 Se 0.999 The thermoelectric cooling devices made of the material and p-type bismuth telluride material achieved maximum cooling temperature differences of 38K, 46K, and 56K at hot-end temperatures of 300K, 323K, and 343K, respectively. Attached Figure Description

[0025] Figure 1 Pb in Examples 1-3 of this invention 0.99875 (GaSb) 0.00125 Se 1-y Powder X-ray diffraction pattern;

[0026] Figure 2 Pb in Examples 1-3 of this invention 0.99875 (GaSb) 0.00125 Se 1-y Conductivity of the material as a function of temperature;

[0027] Figure 3Pb in Examples 1-3 of this invention 0.99875 (GaSb) 0.00125 Se 1-y A plot of the Seebeck coefficient of a material as a function of temperature;

[0028] Figure 4 Pb in Examples 1-3 of this invention 0.99875 (GaSb) 0.00125 Se 1-y Thermal conductivity of a material as a function of temperature;

[0029] Figure 5 Pb in Examples 1-3 of this invention 0.99875 (GaSb) 0.00125 Se 1-y Thermoelectric figure of merit of a material as a function of temperature;

[0030] Figure 6 This is a diagram showing the cooling temperature difference performance of the thermoelectric refrigeration device in Embodiment 4 of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Unless otherwise stated, the raw materials and reagents used in the following embodiments are commercially available products or can be prepared by known methods.

[0032] Prepare raw materials: Pb strips, Ga particles, Sb particles, and Se particles. The purity of the Pb strips is 99.99% (Beijing Haoke Technology Co., Ltd.), the purity of the Ga particles is 99.99% (Beijing Haoke Technology Co., Ltd.), the purity of the Sb particles is 99.99% (Hebei Luohong Technology Co., Ltd.), and the purity of the Se particles is 99.99% (Hebei Luohong Technology Co., Ltd.).

[0033] Example 1 Pb 0.99875 (GaSb) 0.00125 Se 0.999 Preparation

[0034] 1) Weigh out the elements Ga and Sb according to their atomic ratios and pour them into a dried quartz tube. After evacuating the tube, seal it with an oxyhydrogen flame.

[0035] 2) The vacuum quartz tube sealed in step 1) was placed in a muffle furnace for solid-phase reaction. The reaction conditions were: the temperature was raised from room temperature to 800℃ (uniformly increased) over 10 hours, held at 800℃ for 5 hours, and then cooled (uniformly decreased) to room temperature over 12 hours to obtain the GaSb compound.

[0036] 3) Based on the chemical formula Pb0.99875 (GaSb) 0.00125 Se 0.999 The elements Pb, Se and the compound GaSb were weighed out according to the stoichiometric ratio and poured into a dried quartz tube. After evacuation, the quartz tube was sealed with an oxyhydrogen flame.

[0037] 4) The vacuum quartz tube sealed in step 3) was placed in a muffle furnace for a solid-state reaction. The reaction conditions were as follows: the temperature was raised from room temperature (uniformly increased) to 1200℃ over 12 hours, held at 1200℃ for 6 hours, and then quenched in water to obtain Pb. 0.99875 (GaSb) 0.00125 Se 0.999 Compounds.

[0038] Example 2 Pb 0.99875 (GaSb) 0.00125 Se 0.997 Preparation

[0039] 1) Weigh out the elements Ga and Sb according to their atomic ratios and pour them into a dried quartz tube. After evacuating the tube, seal it with an oxyhydrogen flame.

[0040] 2) The vacuum quartz tube sealed in step 1) was placed in a muffle furnace for solid-phase reaction. The reaction conditions were: the temperature was raised from room temperature (uniformly increased) to 800℃ for 10 hours, held at 800℃ for 5 hours, and then cooled to room temperature (uniformly decreased) for 12 hours to obtain GaSb compound.

[0041] 3) Based on the chemical formula Pb 0.99875 (GaSb) 0.00125 Se 0.997 The elements Pb, Se and the compound GaSb were weighed out according to the stoichiometry and poured into a dried quartz tube. After evacuation, the quartz tube was sealed with an oxyhydrogen flame.

[0042] 4) The vacuum quartz tube sealed in step 3) was placed in a muffle furnace for a solid-state reaction. The reaction conditions were as follows: the temperature was raised from room temperature (uniformly increased) to 1200℃ over 12 hours, held at 1200℃ for 6 hours, and then quenched in water to obtain Pb. 0.99875 (GaSb) 0.00125 Se 0.997 Compounds.

[0043] Example 3 Pb 0.99875 (GaSb) 0.00125 Se 0.995 Preparation

[0044] 1) Weigh out the elements Ga and Sb according to their atomic ratios and pour them into a dried quartz tube. After evacuating the tube, seal it with an oxyhydrogen flame.

[0045] 2) The vacuum quartz tube sealed in step 1) was placed in a muffle furnace for solid-phase reaction. The reaction conditions were: the temperature was raised from room temperature (uniformly increased) to 800℃ for 10 hours, held at 800℃ for 5 hours, and then cooled to room temperature (uniformly decreased) for 12 hours to obtain GaSb compound.

[0046] 3) Based on the chemical formula Pb 0.99875 (GaSb) 0.00125 Se 0.995 The elements Pb, Se and the compound GaSb were weighed out according to the stoichiometry and poured into a dried quartz tube. After evacuation, the quartz tube was sealed with an oxyhydrogen flame.

[0047] 4) The vacuum quartz tube sealed in step 3) was placed in a muffle furnace for a solid-state reaction. The reaction conditions were as follows: the temperature was raised from room temperature (uniformly increased) to 1200℃ over 12 hours, held at 1200℃ for 6 hours, and then quenched in water to obtain Pb. 0.99875 (GaSb) 0.00125 Se 0.995 Compounds.

[0048] Example 4: Fabrication of lead selenide-based thermoelectric refrigeration devices

[0049] The chemical formula with the best room-temperature thermoelectric performance obtained from the above preparation is Pb. 0.99875 (GaSb) 0.00125 Se 0.999 The n-type lead selenide and p-type bismuth telluride materials (from RMT Corporation, Russia) were cut to serve as the n-type and p-type legs of the thermoelectric cooling device, respectively. Both the n-type and p-type legs have dimensions of 1×1×1.6mm. 3 A π-type thermoelectric element was connected in series with n-type and p-type thermoelectric legs using Pb95 / Sn5 solder (Zhenjiang Fanyada Electronics Technology Co., Ltd.). The structure consisted of a sandwich layer (ceramic substrate / copper electrode / n-type and p-type thermoelectric legs / copper electrode / ceramic substrate). The soldering temperature was 350℃. The ceramic substrate dimensions were 8.8 × 8.8 × 1.035 mm. 3 (Shenzhen Bomin Electronics Co., Ltd.). The copper electrode thickness is 0.08mm (Aurubis, Germany), and the material is oxygen-free rolled copper. The overall dimensions of the thermoelectric cooling device are 8.8×8.8×3.85mm. 3 .

[0050] Performance testing:

[0051] 1) First, weigh out 0.5 g of Pb. 0.99875 (GaSb) 0.00125 Se 1-x The compound (prepared in Examples 1-3) was then ground into a powder using an agate mortar and pestle, and powder X-ray diffraction analysis was performed. (See attached...) Figure 1 As shown. The test angle was 20-80 degrees, and the X-ray diffraction peaks of the prepared samples were completely consistent with the lead selenide standard card, with no impurity phases observed.

[0052] 2) The electrical properties of the materials prepared in Examples 1-3 were tested using the CTA-3S thermoelectric material testing system from Beijing Creo Technology Co., Ltd. The relationship between conductivity and Seebeck coefficient as a function of temperature is shown in the attached figure. Figure 2 and attached Figure 3 As shown, the electrical conductivity of the prepared material decreases with increasing temperature. The conductivity decreases with increasing GaSb content. At 300 K, Pb... 0.99875 (GaSb) 0.00125 Se 0.999 Pb 0.99875 (GaSb) 0.00125 Se 0.997 and Pb 0.99875 (GaSb) 0.00125 Se 0.995 The electrical conductivity is 1020 S cm. -1 921 S cm -1 and 825 S cm -1 The absolute value of the Seebeck coefficient of the prepared material first increases and then decreases with increasing temperature. At 300K, Pb 0.99875 (GaSb) 0.00125 Se 0.999 Pb 0.99875 (GaSb) 0.00125 Se 0.997 and Pb 0.99875 (GaSb) 0.00125 Se 0.995 The Zebeck coefficients are -197 μV K. -1 -198 μV K -1 and -201 μV K -1 .

[0053] 3) The thermal diffusivity of the materials prepared in Examples 1-3 was measured using a Netzsch LFA 467 laser flare thermal conductivity meter. D Tests were conducted, and the thermal conductivity was measured. κ = C p Dρ The density was calculated. ρ Specific heat was obtained through Archimedes' method. C p Calculated using the Dulong-Petty formula. The relationship between thermal conductivity and temperature is shown in the attached figure. Figure 4 As shown, the thermal conductivity of the prepared material first decreases and then increases with increasing temperature. At 300 K, Pb0.99875 (GaSb) 0.00125 Se 0.999 Pb 0.99875 (GaSb) 0.00125 Se 0.997 and Pb 0.99875 (GaSb) 0.00125 Se 0.995 The thermal conductivity is 1.93 W / m. -1 K -1 1.98 W m -1 K -1 and 2.04W m -1 K -1 . Figure 5 Pb in Examples 1-3 of this invention 0.99875 (GaSb) 0.00125 Se 1-y Thermoelectric figure of merit of the material as a function of temperature is shown in the attached diagram. Figure 5 As shown, at 300K, Pb 0.99875 (GaSb) 0.00125 Se 0.999 Pb 0.99875 (GaSb) 0.00125 Se 0.997 and Pb 0.99875 (GaSb) 0.00125 Se 0.995 Thermoelectric figure of merit ( ZT The values ​​were 0.63, 0.56, and 0.50, respectively. Example 1: Obtained n-type Pb 0.99875 (GaSb) 0.00125 Se 0.999 It exhibits the greatest thermoelectric figure of merit at 300K.

[0054] 4) The thermoelectric cooling device comprehensive testing system (the thermoelectric cooling device comprehensive testing system is a thermoelectric cooling device performance testing device disclosed in Example 1 of CN113466542A, and the measurement is performed according to the method of Example 3 in CN113466542A) is used to test the performance of n-type Pb 0.99875 (GaSb) 0.00125 Se 0.999 Performance tests were conducted on thermoelectric refrigeration devices made of the materials and p-type bismuth telluride. The relationship between the cooling temperature difference and input current at different hot-end temperatures is shown in the attached graph. Figure 6 As shown, with an input current of 3A, the maximum cooling temperature differences obtained at hot-end temperatures of 300K, 323K, and 343K are 38K, 46K, and 56K, respectively.

[0055] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An n-type lead selenide thermoelectric material, characterized in that: The chemical formula of the n-type lead selenide thermoelectric material is Pb. 1-x (GaSb) x Se 1-y Where 0.0001≤x<0.002, 0.0001≤y≤0.

007.

2. The n-type lead selenide thermoelectric material as described in claim 1, characterized in that: 0.001≤y≤0.005。 3. The n-type lead selenide thermoelectric material as described in claim 1, characterized in that: The n-type lead selenide thermoelectric material is Pb. 0.99875 (GaSb) 0.00125 Se 0.999 Pb 0.99875 (GaSb) 0.00125 Se 0.997 or Pb 0.99875 (GaSb) 0.00125 Se 0.995 .

4. A method for preparing an n-type lead selenide thermoelectric material as described in any one of claims 1-3, characterized in that, Specifically, the following steps are included: S1. Prepare raw materials: Pb strips, Ga particles, Sb particles, and Se particles; S2. Weigh out the elements Ga and Sb according to the atomic ratio, pour them into a dried quartz tube, evacuate the tube and seal it with an oxyhydrogen flame, and obtain the GaSb compound after the reaction. S3. Weigh out elemental Pb, Se, and compound GaSb according to their atomic ratios, and pour them into a dried quartz tube. After evacuation, seal the quartz tube with an oxyhydrogen flame. After the reaction, Pb is obtained. 1-x (GaSb) x Se 1-y Compounds.

5. The preparation method according to claim 4, characterized in that: In step S2, the specific reaction process is as follows: the temperature is raised from room temperature to 700-900℃ over 8-12 hours, and held at this temperature for 4-8 hours. After 10-14 hours, the temperature is cooled to room temperature to obtain the GaSb compound. The heating rate is 50-100℃ / h, and the cooling rate is 50-100℃ / h.

6. The preparation method according to claim 4, characterized in that: In step S3, the specific reaction process is as follows: the temperature is raised from room temperature to 1100-1250℃ over 10-14 hours, and held at this temperature for 5-8 hours, followed by water quenching to obtain Pb. 1-x (GaSb) x Se 1-y Compounds; heating rate of 80~120℃ / h.

7. A thermoelectric cooling device, characterized in that, The thermoelectric cooling device includes an n-type lead selenide thermoelectric material and a p-type bismuth telluride thermoelectric material. The n-type material of the thermoelectric cooling device is made of the thermoelectric material described in any one of claims 1-3 or the thermoelectric material prepared by the method described in any one of claims 4-6.

8. A method for preparing the thermoelectric cooling device of claim 7, characterized in that, Includes the following steps: The n-type Pb obtained by claim 4 1-x (GaSb) x Se 1-y The thermoelectric material and p-type bismuth telluride thermoelectric material are cut to serve as n-type and p-type thermoelectric legs, respectively. The n-type and p-type thermoelectric legs are then soldered onto a copper-clad ceramic substrate in an electrically connected series and thermally parallel manner using Pb95 / Sn5 solder to fabricate a thermoelectric cooling device.

9. The method according to claim 8, characterized in that: The n-type Pb 1-x (GaSb) x Se 1-y The thermoelectric material is Pb 0.99875 (GaSb) 0.00125 Se 0.999 .

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