A Mg3Sb2-based thermoelectric device and its fabrication method

Abstract

The application provides a Mg3Sb2-based thermoelectric device and a preparation method thereof, and belongs to the technical field of thermoelectric materials. The Mg3Sb2-based thermoelectric material is made into a powder, and the Mg3Sb2-based thermoelectric device is prepared by using a 3D printing mode; the thermoelectric arm material structure is dense, and the conductivity is good; the thermoelectric device pattern can be flexibly designed according to the application scene by using the 3D printing mode, the application range is wide, and the thermoelectric device with high integration and high power density is easy to prepare; the thermoelectric device preparation process is simple and efficient by using the 3D printing mode, and the development of the batch production technology of the flexible micro thermoelectric device is promoted; the electrode material is connected by using the 3D printing mode, the contact resistance between the electrode material and the thermoelectric material is small, and the output performance of the thermoelectric device is improved.

Description

Technical Field

[0001] This invention relates to the field of thermoelectric device technology, and in particular to a Mg3Sb2-based thermoelectric device and its preparation method. Background Technology

[0002] Among numerous new energy material systems, thermoelectric materials possess significant advantages. They can directly convert thermal energy into electrical energy by utilizing the movement of microscopic charge carriers within the material, thus holding important application value in thermoelectric power generation and solid-state refrigeration. The performance of thermoelectric materials is typically measured by the dimensionless thermoelectric figure of merit zT, where z represents the comprehensive thermal and electrical properties of the thermoelectric material itself, and T represents the absolute temperature of the environment in which the material is used. zT = S 2 σT / κ, where S is the Seebeck coefficient of the material, σ is the electrical conductivity, and κ is the thermal conductivity of the material. 2 σ is the power factor, so high-performance thermoelectric materials should have high electrical conductivity and Seebeck coefficient, as well as low thermal conductivity.

[0003] Thermoelectric devices based on thermoelectric materials have many advantages: (1) high device stability and easy maintenance. Thermoelectric devices do not contain mechanical transmission devices or accessories, and are quiet and vibration-free during operation; (2) environmentally friendly, do not produce toxic or harmful emissions, and can achieve green cooling; (3) simple and compact device structure, easy to miniaturize; (4) suitable for harsh environments such as outer space or remote areas; therefore, they show good application potential in many fields. For example, in the aerospace field, thermoelectric power generation devices provide power for probes performing scientific missions in outer space; in the civilian field, waste heat from factories and exhaust gases from automobiles are used to generate electricity to improve energy efficiency. Currently, automobile companies such as General Motors in the United States and Toyota in Japan have carried out application research on the integration of thermoelectric power generation modules with automobile systems; in the field of refrigeration, thermoelectric cooling devices can be used for local cooling of compact instruments such as lasers and high-performance receivers.

[0004] Currently, most methods for fabricating thermoelectric devices based on thermoelectric materials involve mechanical processing. However, mechanical processing is not only costly, complex, and inefficient, but it is also difficult to fabricate thermoelectric devices with high integration and high power density. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a Mg3Sb2-based thermoelectric device and its preparation method. The preparation method provided by this invention is low in cost, high in efficiency, and easy to prepare thermoelectric devices with high integration and high power density.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for fabricating a Mg3Sb2-based thermoelectric device, comprising the following steps:

[0008] Mg3Sb2-based thermoelectric material powder was mixed with an alcohol solvent to obtain a thermoelectric material slurry;

[0009] According to the preset thermoelectric device pattern, the thermoelectric material slurry is first 3D printed on the substrate surface, and after curing, a Mg3Sb2-based thermoelectric arm is obtained.

[0010] The electrode material slurry is 3D printed onto the substrate surface, and the electrode pattern formed by the second 3D printing is connected to the Mg3Sb2-based thermoelectric arm to obtain the initial thermoelectric device.

[0011] The initial thermoelectric device was annealed to obtain a Mg3Sb2-based thermoelectric device.

[0012] Preferably, the chemical composition of the Mg3Sb2-based thermoelectric material is Mg 3.3-x Co x Sb 2-y-z Bi y Te z , where 0.05≤x≤0.3, 0<y<2, 0<z≤0.03.

[0013] Preferably, the Mg3Sb2-based thermoelectric material is a Mg3Sb2-based thermoelectric material bulk material, and the preparation method of the Mg3Sb2-based thermoelectric material bulk material includes the following steps:

[0014] The elemental components used to prepare Mg3Sb2-based thermoelectric materials were ball-milled and mixed to obtain a mixed powder.

[0015] The mixed powder is hot-pressed to obtain Mg3Sb2-based thermoelectric material bulk material.

[0016] Preferably, the preparation method of the Mg3Sb2-based thermoelectric material powder includes the following steps:

[0017] Mg3Sb2-based thermoelectric materials were ball-milled to obtain Mg3Sb2-based thermoelectric material powder.

[0018] The ball milling rate is 1000-2000 r / min, and the time is 3-5 h;

[0019] The particle size of the Mg3Sb2-based thermoelectric material powder is 5–20 μm.

[0020] Preferably, the mass ratio of the Mg3Sb2-based thermoelectric material powder to the alcohol solvent is 1:0.5 to 1.5.

[0021] Preferably, the electrode material paste is a silver paste;

[0022] The substrate is made of polyimide.

[0023] Preferably, the parameters for the first 3D printing include:

[0024] Printing speed is 5–50 m / min;

[0025] The nozzle diameter is 0.4–0.8 mm;

[0026] The filler density is 0 to 100.

[0027] The parameters for the second 3D printing include:

[0028] Printing speed is 5–50 m / min;

[0029] The nozzle diameter is 0.4–0.8 mm;

[0030] The filling density is 0 to 100.

[0031] Preferably, the number of Mg3Sb2-based thermoelectric arms is one or more; when the number of Mg3Sb2-based thermoelectric arms is more than one, the multiple Mg3Sb2-based thermoelectric arms are connected in series through electrode materials.

[0032] Preferably, the curing temperature is 100–150°C and the curing time is 2–5 hours;

[0033] The annealing process is performed at a temperature of 250–450°C for a time of 30–90 minutes.

[0034] The present invention provides a Mg3Sb2-based thermoelectric device prepared by the above preparation method, comprising a Mg3Sb2-based thermoelectric arm and an electrode material connected to the Mg3Sb2-based thermoelectric arm.

[0035] This invention provides a method for preparing a Mg3Sb2-based thermoelectric device, comprising the following steps: providing a Mg3Sb2-based thermoelectric material; mixing Mg3Sb2-based thermoelectric material powder with an alcohol solvent to obtain a thermoelectric material slurry; firstly 3D printing the thermoelectric material slurry onto a substrate surface according to a preset thermoelectric device pattern, and obtaining a Mg3Sb2-based thermoelectric arm after curing; secondly 3D printing an electrode material slurry onto the substrate surface, connecting the electrode pattern formed by the second inkjet printing with the Mg3Sb2-based thermoelectric arm to obtain an initial thermoelectric device; and annealing the initial thermoelectric device to obtain the Mg3Sb2-based thermoelectric device. This invention prepares Mg3Sb2-based thermoelectric materials into powder and uses 3D printing to fabricate Mg3Sb2-based thermoelectric devices. The thermoelectric arm material has a dense structure and good conductivity. The 3D printing method allows for flexible design of the thermoelectric device pattern according to application scenarios, making it widely applicable and easy to fabricate highly integrated, high-power-density thermoelectric devices. The 3D printing process is simple and efficient, promoting the development of mass production technology for flexible micro-thermoelectric devices. Furthermore, the 3D printing method for connecting electrode materials results in low contact resistance between the electrode and thermoelectric materials, which improves the output performance of the thermoelectric device.

[0036] Furthermore, the present invention uses polyimide as a substrate material, which gives the thermoelectric device a certain degree of deformability, making it suitable for heat source surfaces with varying curvature, thereby significantly improving the waste heat recovery rate and enhancing the output performance of the thermoelectric device. Attached Figure Description

[0037] Figure 1 This is an XRD image of the thermoelectric arm material of the Mg3Sb2-based thermoelectric device in Example 1;

[0038] Figure 2 This is the Seebeck coefficient curve of the thermoelectric arm material of the Mg3Sb2-based thermoelectric device in Example 2, which is related to temperature.

[0039] Figure 3 This is a schematic diagram of the Mg3Sb2-based thermoelectric device in Example 3;

[0040] Figure 4 This is the curve showing the relationship between the output voltage and temperature difference of the Mg3Sb2-based thermoelectric device in Example 3. Detailed Implementation

[0041] This invention provides a method for fabricating a Mg3Sb2-based thermoelectric device, comprising the following steps:

[0042] Mg3Sb2-based thermoelectric material powder was mixed with an alcohol solvent to obtain a thermoelectric material slurry;

[0043] According to the preset thermoelectric device pattern, the thermoelectric material slurry is first 3D printed on the substrate surface, and after curing, a Mg3Sb2-based thermoelectric arm is obtained.

[0044] The electrode material slurry is 3D printed onto the substrate surface, and the electrode pattern formed by the second 3D printing is connected to the Mg3Sb2-based thermoelectric arm to obtain the initial thermoelectric device.

[0045] The initial thermoelectric device was annealed to obtain a Mg3Sb2-based thermoelectric device.

[0046] In this invention, the chemical composition of the Mg3Sb2-based thermoelectric material is preferably Mg. 3.3-x Co x Sb 2-y-z Bi y Te z Where 0.05≤x≤0.3, preferably 0.1≤x≤0.3; 0<y<2, preferably 0.4≤y≤1; 0<z≤0.03, preferably 0.01≤y≤0.02. As a specific embodiment of the present invention, the chemical composition of the Mg3Sb2-based thermoelectric material is Mg 3.1 Co 0.2 Sb 1.5 Bi 0.49 Te 0.01 .

[0047] In this invention, the preparation method of the Mg3Sb2-based thermoelectric material includes the following steps:

[0048] The elemental components used to prepare Mg3Sb2-based thermoelectric materials were ball-milled and mixed to obtain a mixed powder.

[0049] The mixed powder is hot-pressed to obtain Mg3Sb2-based thermoelectric material bulk material.

[0050] This invention involves ball milling and mixing the elemental components of Mg3Sb2-based thermoelectric materials to obtain a mixed powder. Preferably, the purity of the elemental components used to prepare the Mg3Sb2-based thermoelectric materials is ≥99.99%.

[0051] In this invention, the ball milling mixing rate is preferably 1000-2000 r / min, more preferably 1500-1800 r / min; the time is preferably 8-12 h, more preferably 9-10 h.

[0052] This invention involves hot-pressing the mixed powder to obtain Mg3Sb2-based thermoelectric material blocks. In this invention, the hot-pressing temperature is preferably 750–850°C, more preferably 780–820°C; the holding time is preferably 2–40 min, more preferably 10–30 min; and the heating rate to the hot-pressing temperature is preferably 10–50°C / min, more preferably 20–40°C / min. This invention prepares thermoelectric materials through ball milling and rapid hot-pressing, and the resulting thermoelectric materials exhibit excellent thermoelectric properties.

[0053] This invention involves grinding the Mg3Sb2-based thermoelectric material to obtain Mg3Sb2-based thermoelectric material powder. Prior to grinding, this invention preferably polishes the surface of the Mg3Sb2-based thermoelectric material until a bright metallic luster appears on the surface. This invention does not have special requirements for the polishing method; any polishing method well-known to those skilled in the art can be used. Through this polishing, this invention can remove impurities and oxides from the surface of the thermoelectric material.

[0054] In this invention, the grinding method is preferably ball milling, and the ball milling rate is preferably 1000-2000 r / min, more preferably 1500-1800 r / min; the grinding time is preferably 3-5 h, more preferably 4 h. In this invention, after grinding, the obtained powder is preferably sieved to filter out particles with larger and smaller diameters. In this invention, the particle size of the Mg3Sb2-based thermoelectric material powder is preferably 5-20 μm, more preferably 10-15 μm.

[0055] After obtaining the Mg3Sb2-based thermoelectric material powder, the present invention mixes the Mg3Sb2-based thermoelectric material powder with an alcohol solvent to obtain a mixed slurry. In the present invention, the alcohol solvent is preferably a mixture of glycerol, glycerol, and ethanol; the volume ratio of the mixture of glycerol, glycerol, and ethanol is preferably (3-5):(4-9):(3-1), more preferably 4:(6-8):2. In the present invention, the mixing method of glycerol, glycerol, and ethanol is preferably ultrasonic mixing, the ultrasonic mixing power is preferably 30-50W, more preferably 40W; the time is preferably 20-40 min, more preferably 30 min.

[0056] In this invention, the mass ratio of the Mg3Sb2-based thermoelectric material powder to the alcohol solvent is preferably 1:0.5 to 1.5, more preferably 1:0.8 to 1.2, and even more preferably 1:1.

[0057] In this invention, the Mg3Sb2-based thermoelectric material powder and the alcohol solvent are preferably mixed by mechanical stirring, and the mixing time is preferably 5-10 hours, more preferably 6-8 hours. After mixing, the resulting mixture is preferably ground. In this invention, the grinding time is preferably 30-60 minutes, more preferably 40-50 minutes.

[0058] This invention involves inkjet printing a mixed slurry onto a substrate surface according to a pre-defined thermoelectric device pattern, followed by curing to obtain a Mg3Sb2-based thermoelectric arm. In this invention, the substrate is preferably made of polyimide. Prior to the first 3D printing, the substrate is preferably preheated; the preheating temperature is preferably 40–60°C, more preferably 50°C, and the preheating time is preferably 30 minutes.

[0059] In this invention, the parameters of the first 3D printing preferably include:

[0060] The printing speed is 5–50 m / min, more preferably 10–30 m / min;

[0061] The nozzle diameter is 0.4–0.8 mm, more preferably 0.5–0.6 mm;

[0062] The filling density is 0 to 100, more preferably 50 to 80.

[0063] In this invention, the curing temperature is preferably 100–150°C, more preferably 120–140°C; the curing time is preferably 2–5 hours, more preferably 3–4 hours. This invention causes the mixed slurry to solidify through the curing process.

[0064] In this invention, the number of Mg3Sb2-based thermoelectric arms is one or more. This invention does not have a specific requirement for the exact number of Mg3Sb2-based thermoelectric arms; the design can be tailored to the specific usage conditions of the Mg3Sb2-based thermoelectric device.

[0065] This invention involves second-stage 3D printing of electrode material paste onto a substrate surface, connecting the electrode pattern formed by the second 3D printing to the Mg3Sb2-based thermoelectric arm to obtain an initial thermoelectric device. In this invention, the electrode paste is preferably a silver paste. In this invention, the parameters for the second 3D printing preferably include:

[0066] The printing speed is 5–50 m / min, more preferably 10–30 m / min;

[0067] The nozzle diameter is 0.4–0.8 mm, more preferably 0.5–0.6 mm;

[0068] The filling density is 0 to 100, more preferably 50 to 80.

[0069] In this invention, when there are multiple Mg3Sb2-based thermoelectric arms, the multiple Mg3Sb2-based thermoelectric arms are connected in series through electrode materials.

[0070] This invention involves annealing the initial thermoelectric device to obtain a Mg3Sb2-based thermoelectric device. In this invention, the annealing temperature is preferably 250–450°C, more preferably 300–400°C; the annealing time is preferably 30–90 min, more preferably 50–80 min. Through this annealing process, the alcohol solvent in the Mg3Sb2-based thermoelectric arm can be removed, thereby improving the conductivity of the Mg3Sb2-based thermoelectric device.

[0071] The present invention provides a Mg3Sb2-based thermoelectric device prepared by the above preparation method, comprising a Mg3Sb2-based thermoelectric arm and an electrode material connected to the Mg3Sb2-based thermoelectric arm.

[0072] The following detailed description of the Mg3Sb2-based thermoelectric device and its preparation method provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0073] Example 1

[0074] (1) Weigh out the metals Mg, Co, Er, Sb, Bi and Te with a purity of 99.99% in an inert atmosphere according to the stoichiometric ratio of Mg:Co:Sb:Bi:Te=3.1:0.2:1.5:0.49:0.01, put them into a ball mill jar and ball mill for 8 hours;

[0075] (2) The well-mixed powder is hot-pressed to obtain a powder with the composition Mg. 3.1 Co 0.2 Sb 1.5 Bi 0.49 Te 0.01 Thermoelectric material bulk;

[0076] (3) Polish the surface of the thermoelectric material block until it has a bright metallic luster, and grind it in a spherical ink tank for 3 hours to obtain powder material;

[0077] (4) Filter the powder material in (3) through a sieve to remove the larger and smaller particles respectively, and obtain the powder material with a particle size range of 5 to 10 μm.

[0078] (5) Glycerol, glycerol and ethanol are ultrasonically mixed in a volume ratio of 5:4:1 for 20 min to obtain a mixed solution;

[0079] (6) Mix the powder material in (4) with the solution in (5) at a ratio of 1:0.5 and mechanically stir for 5 hours to obtain a uniformly mixed slurry;

[0080] (7) Pour the slurry into an agate mortar and grind for 30 minutes;

[0081] (8) Pour the ground slurry into the 3D printer syringe and set aside;

[0082] (9) Fix the polyimide substrate on a glass plate and place it on a heating stage;

[0083] (10) Preheat the heating plate to 40℃ for 30 minutes. Start 3D printing according to the designed device pattern. Select nozzle diameter of 0.8mm, printing speed of 10m / min, and filling density of 60 to form Mg3Sb2-based thermoelectric arm.

[0084] (11) After printing, cure the material at 100℃ for 2 hours;

[0085] (12) Prepare silver paste, select a nozzle diameter of 0.4 mm, a printing speed of 10 m / min, and a filling density of 80 for 3D printing electrode material on the substrate surface, and connect Mg3Sb2-based thermoelectric arms in series to form an initial thermoelectric device.

[0086] (13) The initial thermoelectric device was annealed at 250°C for 30 min to obtain a Mg3Sb2-based thermoelectric device.

[0087] Using X-rays to perform structural and compositional analysis on thermoelectric arm materials, such as Figure 1 As shown, all diffraction peaks are those of the Mg3Sb2 phase, with no second-phase diffraction peaks appearing, indicating that the material is a pure phase.

[0088] Example 2

[0089] (1) Weigh out metals Mg, Co, Er, Sb, Bi and Te with a purity of 99.99% in an inert atmosphere according to the stoichiometric ratio of Mg:Co:Sb:Bi:Te=3.2:0.1:1:0.99:0.01, put them into a ball mill jar and ball mill for 10 hours;

[0090] (2) The well-mixed powder is hot-pressed to obtain a powder with the composition Mg. 3.2 Co 0.1 SbBi 0.99 Te 0.01 Thermoelectric material bulk;

[0091] (3) Polish the surface of the thermoelectric material block until it has a bright metallic luster, and grind it in a spherical ink tank for 4 hours to obtain powder material;

[0092] (4) Filter the powder material in (3) through a sieve to remove the larger and smaller particles respectively, and obtain the powder material with a particle size range of 10 to 15 μm.

[0093] (5) Glycerol, glycerol and ethanol are ultrasonically mixed in a volume ratio of 4:5:1 for 30 min to obtain a mixed solution;

[0094] (6) Mix the powder material in (4) with the solution in (5) in a 1:1 ratio and mechanically stir for 8 hours to obtain a uniformly mixed slurry;

[0095] (7) Pour the slurry into an agate mortar and grind for 40 minutes;

[0096] (8) Pour the ground slurry into the 3D printer syringe and set aside;

[0097] (9) Fix the polyimide substrate on a glass plate and place it on a heating stage;

[0098] (10) Preheat the heating plate to 50℃ for 30 minutes. Start 3D printing according to the designed device pattern. Select nozzle diameter of 0.4mm, printing speed of 15m / min, and infill density of 70.

[0099] (11) After printing, cure the material at 120℃ for 3 hours;

[0100] (12) Prepare silver paste, 3D printing electrode material, nozzle diameter of 0.4mm, printing speed of 10m / min, filling density of 80, and connect Mg3Sb2-based thermoelectric arms in series to form the initial thermoelectric device.

[0101] (13) The initial thermoelectric device was annealed at 300℃ for 60 min to obtain a Mg3Sb2-based thermoelectric device.

[0102] The electrical properties of thermoelectric arm materials are characterized using a thermoelectric parameter measurement system, such as... Figure 2 As shown in the figure, the room temperature conductivity of the material is approximately 7 × 10⁻⁶. 4 S / m; As the temperature increases, the conductivity gradually decreases, exhibiting semiconductor conductivity characteristics.

[0103] Example 3

[0104] (1) Weigh out the metals Mg, Co, Er, Sb, Bi and Te with a purity of 99.99% in an inert atmosphere according to the stoichiometric ratio of Mg:Co:Sb:Bi:Te=3.15:0.15:1.5:0.48:0.02, put them into a ball mill jar and ball mill for 12 hours;

[0105] (2) The well-mixed powder is hot-pressed to obtain a powder with the composition Mg. 3.15 Co 0.15 Sb 1.5 Bi 0.48 Te 0.02 Thermoelectric material bulk;

[0106] (3) Polish the surface of the thermoelectric material block until it has a bright metallic luster, and grind it in a spherical ink tank for 5 hours to obtain powder material;

[0107] (4) Filter the powder material in (3) through a sieve to remove the larger and smaller particles respectively, and obtain the powder material with a particle size range of 10-20μm.

[0108] (5) Glycerol, glycerol and ethanol were ultrasonically mixed for 40 min at a volume ratio of 3:5:2 to obtain a mixed solution;

[0109] (6) Mix the powder material in (4) with the solution in (5) at a ratio of 1:1.5 and mechanically stir for 10 hours to obtain a uniformly mixed slurry;

[0110] (7) Pour the slurry into an agate mortar and grind for 60 minutes;

[0111] (8) Pour the ground slurry into the syringe of the 3D printer and set aside;

[0112] (9) Fix the polyimide substrate on a glass plate and place it on a heating stage;

[0113] (10) Preheat the heating plate to 60℃ for 30 minutes. Start 3D printing according to the designed device pattern. Select nozzle diameter of 0.8mm, printing speed of 20m / min, and infill density of 80.

[0114] (11) After printing, cure the material at 150℃ for 5 hours;

[0115] (12) Prepare silver paste, 3D printing electrode material, nozzle diameter of 0.4mm, printing speed of 10m / min, filling density of 90, and connect Mg3Sb2-based thermoelectric arms in series to form the initial thermoelectric device.

[0116] (13) The initial thermoelectric device was annealed at 400℃ for 50 min to obtain the Mg3Sb2-based thermoelectric device.

[0117] Figure 3 This is a schematic diagram of a Mg3Sb2 thermoelectric device, consisting of four thermoelectric arms connected in series with silver as the electrode material. The output voltage of this thermoelectric device was tested at different temperature differences, such as... Figure 4As shown in the figure, it can be seen that the output voltage of the device continuously increases with the increase of the temperature difference.

[0118] Comparative Example 1

[0119] (1) Weigh out the metals Mg, Co, Er, Sb, Bi and Te with a purity of 99.99% in an inert atmosphere according to the stoichiometric ratio of Mg:Co:Sb:Bi:Te=3.15:0.15:1.5:0.48:0.02, put them into a ball mill jar and ball mill for 12 hours;

[0120] (2) The well-mixed powder is hot-pressed to obtain a powder with the composition Mg. 3.15 Co 0.15 Sb 1.5 Bi 0.48 Te 0.02 Thermoelectric material bulk;

[0121] (3) Polish the surface of the thermoelectric material block until it has a bright metallic luster;

[0122] (4) Mechanically cut the thermoelectric material so that the thermoelectric arm size is the same as in Example 3;

[0123] (5) The Ag electrode material is connected in series with the thermoelectric arm by welding to form a thermoelectric device.

[0124] In the comparative examples, mechanical cutting was chosen to obtain the desired thermoelectric arm, which significantly limited its size. High-precision cutting machines can achieve millimeter-level accuracy, but stress during the cutting process often leads to material cracking, increasing experimental uncertainty. Furthermore, high-precision cutting machines are expensive, increasing the processing cost of thermoelectric devices. Welding is another option for connecting the electrode material and the thermoelectric arm material. This method often increases the resistance between the thermoelectric arm and electrode materials, reducing device output performance. Increased interface resistance also leads to severe overheating, potentially causing interface cracking.

[0125] The embodiment utilizes a single 3D printing device to simultaneously fabricate the thermoelectric arm and ensure a smooth connection between the thermoelectric arm and the electrode material. Furthermore, this automated printing technology can easily print thermoelectric arms at the micrometer (μm) scale, rapidly printing highly integrated micro-thermoelectric devices based on pre-designed device patterns, which is beneficial for mass production.

[0126] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating a Mg3Sb2-based thermoelectric device, comprising the following steps: Mg3Sb2-based thermoelectric material powder was mixed with an alcohol solvent to obtain a thermoelectric material slurry; According to the preset thermoelectric device pattern, the thermoelectric material slurry is first 3D printed on the substrate surface, and after curing, a Mg3Sb2-based thermoelectric arm is obtained. The electrode material slurry is 3D printed onto the substrate surface, and the electrode pattern formed by the second 3D printing is connected to the Mg3Sb2-based thermoelectric arm to obtain the initial thermoelectric device. The initial thermoelectric device was annealed to obtain a Mg3Sb2-based thermoelectric device; The chemical composition of the Mg3Sb2-based thermoelectric material is Mg 3.3-x Co x Sb 2-y-z Bi y Te z , where 0.05≤ x ≤0.3, 0< y <2, 0< z ≤0.03, the particle size of the Mg3Sb2-based thermoelectric material powder is 5~20μm; The electrode material paste is silver paste; the substrate is made of polyimide. The curing temperature is 100~150℃, and the time is 2~5h; The annealing process is performed at a temperature of 250~450℃ for a time of 30~90 minutes.

2. The preparation method according to claim 1, characterized in that, The Mg3Sb2-based thermoelectric material is a Mg3Sb2-based thermoelectric material bulk material, and the preparation method of the Mg3Sb2-based thermoelectric material bulk material includes the following steps: The elemental components used to prepare Mg3Sb2-based thermoelectric materials were ball-milled and mixed to obtain a mixed powder. The mixed powder is hot-pressed to obtain Mg3Sb2-based thermoelectric material bulk material.

3. The preparation method according to claim 1, characterized in that, The preparation method of the Mg3Sb2-based thermoelectric material powder includes the following steps: Mg3Sb2-based thermoelectric materials were ball-milled to obtain Mg3Sb2-based thermoelectric material powder. The ball milling rate is 1000~2000 r / min, and the time is 3~5 h.

4. The preparation method according to claim 1 or 3, characterized in that, The mass ratio of the Mg3Sb2-based thermoelectric material powder to the alcohol solvent is 1:0.5~1.

5.

5. The preparation method according to claim 1, characterized in that, The parameters of the first 3D print include: Printing speed is 5~50m / min; The nozzle diameter is 0.4~0.8mm; The filler density is 0~100; The parameters for the second 3D printing include: Printing speed is 5~50m / min; The nozzle diameter is 0.4~0.8mm; The filler density is 0~100.

6. The preparation method according to claim 1, characterized in that, The number of Mg3Sb2-based thermoelectric arms is one or more; when the number of Mg3Sb2-based thermoelectric arms is more than one, the multiple Mg3Sb2-based thermoelectric arms are connected in series through electrode materials.

7. The Mg3Sb2-based thermoelectric device prepared by the preparation method according to any one of claims 1 to 6 includes a Mg3Sb2-based thermoelectric arm and an electrode material connected to the Mg3Sb2-based thermoelectric arm.

Images