Preparation method and application of water-based bismuth telluride ink and preparation method of Bi2Te3-based thermoelectric material
Through the preparation method of water-based bismuth telluride ink and 3D printing technology, the problems of high cost and general performance of Bi2Te3-based thermoelectric materials were solved, and Bi2Te3-based thermoelectric materials with high compressive strength and excellent thermoelectric properties were achieved.
Patent Information
- Application Number
- CN202510821548.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-19
- Publication Date
- 2025-10-14
AI Technical Summary
Existing methods for preparing Bi2Te3-based thermoelectric materials are costly and offer mediocre performance. The use of inks containing organic binders leads to a decrease in thermoelectric performance after sintering, making it difficult to achieve efficient thermoelectric conversion.
A water-based bismuth telluride ink preparation method is adopted. By mixing polyvinyl pyrrolidone, methyl cellulose, polyethyleneimine and solvent in specific proportions, an ink with suitable viscoelastic properties is formed. Combined with 3D printing technology, Bi2Te3-based thermoelectric materials are prepared, and the pore structure is controlled to improve the thermoelectric performance.
The high compressive strength and excellent thermoelectric performance of Bi2Te3-based thermoelectric materials are achieved. The scattering effect of phonons is enhanced through nanoscale and microscale pores, the state density of carriers is increased, and the thermoelectric performance is synergistically regulated.
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Figure CN120774385A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of thermoelectric materials, and in particular to a preparation method and application of a water-based bismuth telluride ink and a preparation method of a Bi2Te3-based thermoelectric material. Background Art
[0002] Thermoelectric materials can directly convert waste heat into electrical energy by using the Seebeck effect, and do not produce any environmental pollution during the energy conversion process, thus improving energy utilization and further alleviating the energy crisis. In addition, the Peltier effect of thermoelectric materials can be used to convert electrical energy into temperature difference to realize functional materials for cooling. Due to the simple structure of thermoelectric devices and the lack of moving parts, they have broad application prospects in waste heat recovery and electronic cooling. Among them, the performance of thermoelectric materials and their devices is coupled with the parameters of the materials, that is, ZT=S 2 σT / κ, where S, σ, T, and κ represent the Seebeck coefficient, electrical conductivity, operating temperature, and thermal conductivity, respectively. To maximize the energy conversion efficiency of materials, numerous strategies, such as defect engineering and band engineering, have been employed to increase the zT value. Over the past few decades, researchers have discovered numerous thermoelectric materials with exceptional properties, such as Bi2Te3, PbTe, Mg3Sb2, and their alloys. However, among these materials, Bi2Te3-based thermoelectric materials are the only ones to achieve commercial application due to their high medium- and low-temperature performance and excellent stability.
[0003] Bismuth telluride-based thermoelectric materials exhibit excellent thermoelectric performance at low temperatures and are among the most promising thermoelectric materials for large-scale application. Currently, Bi2Te3-based thermoelectric materials are typically prepared using zone melting, ball milling, hot pressing, and hydrothermal methods. Selecting one or two of these methods can yield limited performance and high production costs.
[0004] Ink direct writing technology integrates multiple disciplines such as physics, chemistry, optics, materials, electromechanics, and software engineering. The cross-integration of various disciplines has formed a unique high-end manufacturing technology that can selectively control or change the physical state and properties of materials from multiple scales and dimensions, becoming a cutting-edge hotspot in the manufacturing field. This technology can deposit ink on a substrate according to a pre-designed structure, and through the control of factors such as airflow, movement speed, and spacing, it can precisely achieve structural molding from point to line to surface, from part to whole. Unlike traditional subtractive manufacturing, this additive manufacturing process is simple to operate, has no material waste, and can form various complex structures in one go. It undoubtedly has the potential to solve the difficulties in the manufacture of thermoelectric materials and devices. Applying ink direct writing to thermoelectric conversion technology can print small and micro devices for flexible wearable electronic components, as well as large and complex structure devices for irregular surfaces.
[0005] Extrusion direct writing printing using colloidal viscoelastic inks containing inorganic particles has the advantages of simple processing and reasonable equipment prices, promoting the feasibility of new manufacturing technologies and customized thermoelectric devices. To date, it has been widely used in various thermoelectric materials, including conductive polymers, Bi2Te3, SnSe and other compounds. However, this manufacturing technology has been plagued by low thermoelectric performance (ZT value). This is mainly due to the fact that in order to improve the viscoelastic properties of thermoelectric inks, a large amount of organic binder is added, which leads to a significant decrease in the thermoelectric performance of the material after sintering. Therefore, finding a thermoelectric ink with ultra-low organic content and suitable rheological properties is crucial to improving the thermoelectric performance of the material. Summary of the Invention
[0006] In view of the problems existing in the prior art, the present invention provides a preparation method and application of a water-based bismuth telluride ink and a preparation method of a Bi2Te3-based thermoelectric material.
[0007] The technical solution adopted by the present invention is: a method for preparing a water-based bismuth telluride ink, comprising the following steps:
[0008] Step 1: Weigh the raw materials according to the set chemical formula atomic ratio, ball mill, grind, disperse and sieve to obtain raw material powder;
[0009] Step 2: adding the polyvinyl pyrrolidone solution dropwise to the methyl cellulose solution to obtain solution A; the mass ratio of the polyvinyl pyrrolidone to the methyl cellulose is 1-4:1-5;
[0010] Step 3: adding solution A dropwise to the polyethyleneimine solution and mixing thoroughly, and then adding a solvent dropwise to obtain solution B; the mass ratio of the polyethyleneimine to the methylcellulose is 0.5-2:1-5;
[0011] Step 4: Add the raw material powder in step 1 to solution B, stir and disperse to obtain the required ink; the mass of the organic matter accounts for 0.45% to 0.65% of the mass of the raw material powder; the organic matter is the total mass of polyvinyl pyrrolidone, methyl cellulose, polyethyleneimine and solvent.
[0012] Furthermore, the solvent is obtained by mixing dimethylformamide and polyacrylic acid in a molar ratio of 1:2.
[0013] Furthermore, in step 4, the dispersion is carried out by a centrifuge, the centrifuge speed is 400 rpm, and the dispersion time is 1 hour.
[0014] The invention discloses an application of a water-based bismuth telluride ink, wherein the water-based bismuth telluride ink is used to prepare a p-type or n-type Bi2Te3-based thermoelectric material.
[0015] Furthermore, the Bi2Te3-based thermoelectric material is n-type Bi2Te 2.6 Se0.4 and p-type Bi 0.5 Sb 1.5 Te3.
[0016] A method for preparing a Bi2Te3-based thermoelectric material, comprising the following steps:
[0017] S1: using a water-based bismuth telluride ink to 3D print a Bi2Te3-based thermoelectric material blank;
[0018] S2: annealing the blank in step S1 to obtain the required Bi2Te3-based thermoelectric material.
[0019] Further, the 3D printing in step S1 is DIW printing.
[0020] Further, the printing conditions are as follows: the printing speed is 6-20 mm / s, the filling interval is 0.35-0.45 mm, and the printing layer height is 0.38-0.48 mm; and the air pressure during printing is 0.1-0.4 MPa.
[0021] Further, before the annealing in step S2, first heating and drying are performed, and the drying system is as follows:
[0022] holding at 25℃ for 12h, holding at 50℃ for 5h, holding at 70℃ for 12h, and holding at 90℃ for 5h.
[0023] Further, the annealing temperature in step S2 is 460-500℃, and the annealing time is 60-180 min.
[0024] The beneficial effects of the present application are:
[0025] (1) The organic matter used in the preparation of the ink in the present application is obtained by specific substances and proportions, and the obtained ink not only has suitable viscoelastic properties but also provides a basis for improving the thermoelectric performance;
[0026] (2) The thermoelectric material obtained in the present application has a large number of nanoscale and micrometer-scale pores, which improves the scattering effect of phonons, thereby reducing the lattice thermal conductivity, and increases the state density effective mass of the charge carriers to improve the Seebeck coefficient, and under the synergistic control, excellent thermoelectric performance is achieved. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 It is a schematic diagram of the preparation process of the thermoelectric material of the present application.
[0028] Figure 2 It is the drying and annealing system used in the preparation process of the thermoelectric material of Example 1 of the present application, A is the drying system, and B is the annealing system.
[0029] Figure 3 Fracture morphology of the thermoelectric materials obtained in Examples 1 and 4 of the present application, a is the fracture morphology of the p-type thermoelectric material obtained in Example 4; b is the fracture morphology of the p-type thermoelectric material obtained in Example 1, c is the fracture morphology of the n-type thermoelectric material obtained in Example 4, and d is the fracture morphology of the n-type thermoelectric material obtained in Example 1.
[0030] Figure 4 Compression strength curve of the p-type and n-type thermoelectric materials obtained in Example 1 of the present application.
[0031] Figure 5 Performance test results of the inks obtained in Examples 1-3 and Comparative Example 1 of the present application, a is viscosity, and b is storage modulus.
[0032] Figure 6 Thermoelectric performance test results of the p-type and n-type thermoelectric materials obtained in Examples 1, 4 and 5 of the present application, a, c and e are p-type thermoelectric materials, and b, d and f are n-type thermoelectric materials.
[0033] Figure 7 Thermoelectric performance test results of the p-type and n-type thermoelectric materials obtained in Examples 1, 6 and 7 of the present application, a, c and e are p-type thermoelectric materials, and b, d and f are n-type thermoelectric materials. DETAILED DESCRIPTION
[0034] The present application will be further described below in conjunction with the accompanying drawings and specific examples.
[0035] As shown in Figure 1 A preparation method of a water-based bismuth telluride ink, comprising the following steps:
[0036] Step 1: weighing raw materials according to the set chemical formula atomic ratio, ball milling, grinding, dispersing and sieving to obtain raw material powder;
[0037] Step 2: dropping polyvinylpyrrolidone solution into methyl cellulose solution to obtain solution A; the mass ratio of the polyvinylpyrrolidone and the methyl cellulose is 1-4:1-5;
[0038] Step 3: dropping solution A into polyethyleneimine solution, mixing thoroughly, and dropping solvent to obtain solution B; the mass ratio of the polyethyleneimine and the methyl cellulose is 0.5-2:1-5; the solvent is a mixture of dimethylformamide and polyacrylic acid in a molar ratio of 1:2.
[0039] Step 4: Add the raw material powder from Step 1 to Solution B and stir to disperse the resulting ink. The organic matter accounts for 0.45% to 0.65% of the raw material powder mass; the organic matter is the combined mass of polyvinyl pyrrolidone, methylcellulose, polyethyleneimine, and solvent. Dispersion is performed in a centrifuge at 400 rpm for 1 hour. Water-based bismuth telluride ink is used to prepare p-type or n-type Bi2Te3-based thermoelectric materials. Hydrogen atoms attached to the amino groups (-NH2) of the highly branched PEI molecules interact with oxygen atoms in the carbonyl groups (C=O) within the PVP chains. These interactions lead to the formation of a hydrogen bond crosslinking network, thereby enhancing the viscoelasticity of the ink. MC also significantly enhances the viscosity of the material. DMF and PAA act as charge repulsion, allowing them to adhere to the particle surface, enhancing electrostatic repulsion and preventing interparticle aggregation.
[0040] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0041] S1: 3D printing of a Bi2Te3-based thermoelectric material blank using water-based bismuth telluride ink. DIW printing was used. Printing conditions were as follows: a print rate of 6–20 mm / s, a fill gap of 0.35–0.45 mm, a layer height of 0.38–0.48 mm, and an air pressure of 0.1–0.4 MPa during printing.
[0042] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0043] Keep warm at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The annealing temperature is 460-500°C, and the annealing time is 60-180 minutes.
[0044] Example 1
[0045] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0046] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0047] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0048] Step 2: Add 0.2 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0049] 0.2 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0050] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0051] Step 3: Add 0.1 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0052] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0053] 0.2 g of dimethylformamide (DMF) and 0.4 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0054] Slowly drop it into the mixed solution of A and polyethyleneimine, and stir magnetically until the solution is mixed.
[0055] Step 4: Add 20g of each of the p-type and n-type ball-milled Bi2Te3-based thermoelectric powders to the solution obtained in Step 3 (prepared in duplicate using the same method) and rapidly stir to form a uniformly dispersed, viscoelastic ink. This is then centrifuged at 400 rpm for 1 hour to obtain a uniformly dispersed, viscoelastic thermoelectric ink. The organic content is 0.45%.
[0056] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0057] S1: Use water-based bismuth telluride ink (n-type and p-type inks are prepared in sequence according to the following method to obtain n-type thermoelectric materials and p-type thermoelectric materials, respectively) to print Bi2Te3-based thermoelectric material blanks by DIW; use Ultimaker-Cura software to model the size and shape of the printed sample, and then add the prepared thermoelectric ink to a syringe (10ml) with a metal nozzle with an inner diameter of 410um. The layer-by-layer deposition of the thermoelectric slurry is controlled on a pneumatic extrusion 3D printer based on three-axis motion to construct the desired shape, thereby achieving continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0058] The printing conditions are as follows: printing speed of 15 mm / s, infill spacing of 0.40 mm, and printing layer height of 0.40 mm; the air pressure during printing is 0.2 MPa.
[0059] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0060] Keep the temperature at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The heating rate is 3°C / min, the annealing temperature is 480°C, and the annealing time is 120 minutes.
[0061] The compressive strength of the p-type thermoelectric material and the n-type thermoelectric material obtained in this embodiment is as follows: Figure 4 As shown in the figure, the compressive stress-strain curve shows that the compressive strength of the p-type sample is much higher than that of the n-type sample. This is mainly due to the higher density and lower porosity of the p-type sample after annealing. The compressive strength of the bismuth telluride material printed with the water-based ink obtained in this example exceeds the currently reported 20 MPa.
[0062] Example 2
[0063] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0064] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0065] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0066] Step 2: Add 0.1 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0067] 0.1 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0068] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0069] Step 3: Add 0.2 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0070] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0071] 0.17 g of dimethylformamide (DMF) and 0.33 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0072] Slowly drop it into the mixed solution of A and polyethyleneimine, and stir magnetically until the solution is mixed.
[0073] Step 4: Add 20g of each of the p-type and n-type ball-milled Bi2Te3-based thermoelectric powders to the solution obtained in Step 3 (prepared in duplicate using the same method) and rapidly stir to form a uniformly dispersed, viscoelastic ink. This is then centrifuged at 400 rpm for 1 hour to obtain a uniformly dispersed, viscoelastic thermoelectric ink. The organic content is 0.45%.
[0074] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0075] S1: Use water-based bismuth telluride ink (n-type and p-type inks are prepared in sequence according to the following method to obtain n-type thermoelectric materials and p-type thermoelectric materials, respectively) to print Bi2Te3-based thermoelectric material blanks by DIW; use Ultimaker-Cura software to model the size and shape of the printed sample, and then add the prepared thermoelectric ink to a syringe (10ml) with a metal nozzle with an inner diameter of 410um. The layer-by-layer deposition of the thermoelectric slurry is controlled on a pneumatic extrusion 3D printer based on three-axis motion to construct the desired shape, thereby achieving continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0076] The printing conditions are as follows: printing speed of 20 mm / s, infill spacing of 0.45 mm, and printing layer height of 0.38 mm; the air pressure during printing is 0.1 MPa.
[0077] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0078] Keep the temperature at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The heating rate is 3°C / min, the annealing temperature is 480°C, and the annealing time is 120 minutes.
[0079] Example 3
[0080] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0081] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0082] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0083] Step 2: Add 0.4 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0084] 0.5 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0085] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0086] Step 3: Add 0.05 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0087] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0088] 0.12 g of dimethylformamide (DMF) and 0.23 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0089] Slowly drop it into the mixed solution of A and polyethyleneimine, and stir magnetically until the solution is mixed.
[0090] Step 4: Add 20g of each of the p-type and n-type ball-milled Bi2Te3-based thermoelectric powders to the solution obtained in Step 3 (prepared in duplicate using the same method) and rapidly stir to form a uniformly dispersed, viscoelastic ink. This is then centrifuged at 400 rpm for 1 hour to obtain a uniformly dispersed, viscoelastic thermoelectric ink. The organic content is 0.65%.
[0091] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0092] S1: Use water-based bismuth telluride ink (n-type and p-type inks are prepared in sequence according to the following method to obtain n-type thermoelectric materials and p-type thermoelectric materials, respectively) to print Bi2Te3-based thermoelectric material blanks by DIW; use Ultimaker-Cura software to model the size and shape of the printed sample, and then add the prepared thermoelectric ink to a syringe (10ml) with a metal nozzle with an inner diameter of 410um. The layer-by-layer deposition of the thermoelectric slurry is controlled on a pneumatic extrusion 3D printer based on three-axis motion to construct the desired shape, thereby achieving continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0093] The printing conditions are as follows: the printing rate is 6 mm / s, the filling spacing is 0.35 mm, and the printing layer height is 0.48 mm; the air pressure during printing is 0.4 MPa.
[0094] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0095] Keep the temperature at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The heating rate is 3°C / min, the annealing temperature is 480°C, and the annealing time is 120 minutes.
[0096] Figure 5 The performance test results of the inks obtained for Examples 1, 2, and 3 are shown in the figure. As can be seen from the figure, the increase in the organic matter content helps to enhance the viscosity and storage modulus of the ink, so that the ink maintains good structural support during the printing process. In addition, the increase in the organic matter content allows the ink to maintain a certain solid structure even under higher forces. A content below 0.45%, such as 0.35% (the remaining steps are the same as in Example 1 for the comparative example, except that the organic matter content is adjusted to 0.35% of the thermoelectric material), exhibits a completely liquid-like structure, which is obviously not conducive to the molding and curing of the printed structure.
[0097] Example 4
[0098] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0099] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0100] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0101] Step 2: Add 0.2 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0102] 0.2 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0103] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0104] Step 3: Add 0.1 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0105] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0106] 0.2 g of dimethylformamide (DMF) and 0.4 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0107] Slowly drop it into the mixed solution of A and polyethyleneimine, and stir magnetically until the solution is mixed.
[0108] Step 4: Add 20g of each of the p-type and n-type ball-milled Bi2Te3-based thermoelectric powders to the solution obtained in Step 3 (prepare two portions using the same method) and rapidly stir to form a uniformly dispersed, viscoelastic ink. This is then centrifuged at 400 rpm for 1 hour to obtain a uniformly dispersed, viscoelastic thermoelectric ink.
[0109] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0110] S1: Use water-based bismuth telluride ink (n-type and p-type inks are prepared in sequence according to the following method to obtain n-type thermoelectric materials and p-type thermoelectric materials, respectively) to print Bi2Te3-based thermoelectric material blanks by DIW; use Ultimaker-Cura software to model the size and shape of the printed sample, and then add the prepared thermoelectric ink to a syringe (10ml) with a metal nozzle with an inner diameter of 410um. The layer-by-layer deposition of the thermoelectric slurry is controlled on a pneumatic extrusion 3D printer based on three-axis motion to construct the desired shape, thereby achieving continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0111] The printing conditions are as follows: printing speed of 15 mm / s, infill spacing of 0.40 mm, and printing layer height of 0.40 mm; the air pressure during printing is 0.2 MPa.
[0112] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0113] Keep the temperature at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The heating rate is 3°C / min, the annealing temperature is 460°C, and the annealing time is 120 minutes.
[0114] Example 5
[0115] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0116] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0117] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0118] Step 2: Add 0.2 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0119] 0.2 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0120] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0121] Step 3: Add 0.1 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0122] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0123] 0.2 g of dimethylformamide (DMF) and 0.4 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0124] Slowly drop it into the mixed solution of A and polyethyleneimine, and stir magnetically until the solution is mixed.
[0125] Step 4: Add 20g of each of the p-type and n-type ball-milled Bi2Te3-based thermoelectric powders to the solution obtained in Step 3 (prepare two portions using the same method) and rapidly stir to form a uniformly dispersed, viscoelastic ink. This is then centrifuged at 400 rpm for 1 hour to obtain a uniformly dispersed, viscoelastic thermoelectric ink.
[0126] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0127] S1: Use water-based bismuth telluride ink (n-type and p-type inks are prepared in sequence according to the following method to obtain n-type thermoelectric materials and p-type thermoelectric materials, respectively) to print Bi2Te3-based thermoelectric material blanks by DIW; use Ultimaker-Cura software to model the size and shape of the printed sample, and then add the prepared thermoelectric ink to a syringe (10ml) with a metal nozzle with an inner diameter of 410um. The layer-by-layer deposition of the thermoelectric slurry is controlled on a pneumatic extrusion 3D printer based on three-axis motion to construct the desired shape, thereby achieving continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0128] The printing conditions are as follows: printing speed of 15 mm / s, infill spacing of 0.40 mm, and printing layer height of 0.40 mm; the air pressure during printing is 0.2 MPa.
[0129] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0130] Keep the temperature at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The heating rate is 3°C / min, the annealing temperature is 500°C, and the annealing time is 120 minutes.
[0131] Example 6
[0132] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0133] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0134] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0135] Step 2: Add 0.2 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0136] 0.2 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0137] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0138] Step 3: Add 0.1 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0139] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0140] 0.2 g of dimethylformamide (DMF) and 0.4 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0141] Slowly drop it into the mixed solution of A and polyethyleneimine, and stir magnetically until the solution is mixed.
[0142] Step 4: Add 20g of each of the p-type and n-type ball-milled Bi2Te3-based thermoelectric powders to the solution obtained in Step 3 (prepare two portions using the same method) and rapidly stir to form a uniformly dispersed, viscoelastic ink. This is then centrifuged at 400 rpm for 1 hour to obtain a uniformly dispersed, viscoelastic thermoelectric ink.
[0143] A method for preparing a Bi2Te3-based thermoelectric material comprises the following steps:
[0144] S1: Use water-based bismuth telluride ink (n-type and p-type inks are prepared in sequence according to the following method to obtain n-type thermoelectric materials and p-type thermoelectric materials, respectively) to print Bi2Te3-based thermoelectric material blanks by DIW; use Ultimaker-Cura software to model the size and shape of the printed sample, and then add the prepared thermoelectric ink to a syringe (10ml) with a metal nozzle with an inner diameter of 410um. The layer-by-layer deposition of the thermoelectric slurry is controlled on a pneumatic extrusion 3D printer based on three-axis motion to construct the desired shape, thereby achieving continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0145] The printing conditions are as follows: printing speed of 15 mm / s, infill spacing of 0.40 mm, and printing layer height of 0.40 mm; the air pressure during printing is 0.2 MPa.
[0146] S2: Anneal the green body from step S1 to obtain the desired Bi2Te3-based thermoelectric material. Heat and dry the green body before annealing. The drying process is as follows:
[0147] Keep the temperature at 25°C for 12 hours, at 50°C for 5 hours, at 70°C for 12 hours, and at 90°C for 5 hours. The heating rate is 3°C / min, the annealing temperature is 480°C, and the annealing time is 60 minutes.
[0148] Example 7
[0149] A method for preparing a water-based bismuth telluride ink comprises the following steps:
[0150] Step 1: Prepare the raw materials Bi powder, Te powder, Sb powder and Se powder according to the p-type Bi 0.5 Sb 1.5 Te3 and n-type Bi2Te 2.6 Se 0.4 The chemical formula atomic ratio was weighed and mixed in an argon glove box, and then alumina balls with a diameter of 5 mm were added, wherein the weight ratio of balls: powder = 5:1. The powder and alumina balls were added together into a planetary ball mill and ball milled for 10 hours under a protective atmosphere;
[0151] The ball-milled powder was poured out in an argon glove box for manual grinding and dispersion, and then the powder was sieved using a sieve to obtain a powder with a uniform particle size distribution of 1-100 μm.
[0152] Step 2: Add 0.2 g of polyvinylpyrrolidone (PVP) to a beaker containing 10 mL of deionized water and stir magnetically to form a polyvinylpyrrolidone solution.
[0153] 0.2 g of methylcellulose MC was added to a beaker containing 10 mL of deionized water and stirred magnetically to obtain a methylcellulose solution.
[0154] The polyvinyl pyrrolidone solution was added dropwise to the methyl cellulose solution, and magnetic stirring was performed for 30 minutes until the solutions were mixed to obtain solution A.
[0155] Step 3: Add 0.1 g of polyethyleneimine (PEI) into a beaker containing 5 mL of deionized water and stir magnetically to obtain a polyethyleneimine solution.
[0156] Under stirring conditions, solution A was added dropwise to the polyethyleneimine solution and magnetically stirred for 30 min until the solutions were mixed.
[0157] 0.2 g of dimethylformamide (DMF) and 0.4 g of polyacrylic acid (PAA) were added to a beaker containing 5 mL of deionized water and stirred magnetically to obtain a solvent.
[0158] It was slowly dripped into the mixed solution of A and polyethyleneimine, and magnetically stirred until the solution was mixed.
[0159] Step 4: 20g of p-type and n-type ball-milled Bi2Te3-based thermoelectric powder was added into the solution obtained in step 3 (two portions were prepared in the same way) respectively, and fast stirring was performed. It was formed into a uniformly dispersed and viscoelastic ink. Then it was added into a high-energy centrifuge at a speed of 400 rpm for 1h to obtain a uniformly dispersed and viscoelastic thermoelectric ink.
[0160] A method for preparing a Bi2Te3-based thermoelectric material, comprising the following steps:
[0161] S1: Bi2Te3-based thermoelectric material blanks were printed by DIW (n-type and p-type inks were sequentially prepared according to the following method to obtain n-type and p-type thermoelectric materials, respectively); Ultimaker-Cura software was used to model the size and shape of the printed sample, and then the prepared thermoelectric ink was added to a syringe (10ml) with a metal nozzle of 410um inner diameter, and the layer-by-layer deposition of the thermoelectric slurry was controlled in a pneumatic extrusion 3D printer based on three-axis motion to build the required shape to realize continuous printing of Bi2Te3-based thermoelectric material samples at room temperature.
[0162] The printing conditions were as follows: printing rate was 15mm / s, filling interval was 0.40mm, and printing layer height was 0.40mm; the air pressure during printing was 0.2MPa.
[0163] S2: The blanks in step S1 were annealed to obtain the required Bi2Te3-based thermoelectric material. Before annealing, heating and drying were first performed, and the drying schedule was as follows:
[0164] The temperature was kept at 25℃ for 12h, at 50℃ for 5h, at 70℃ for 12h, and at 90℃ for 5h. The heating rate was 3℃ / min, the annealing temperature was 480℃, and the annealing time was 180min.
[0165] Figure 3 Fracture morphology of the thermoelectric material obtained in Example 1 and Example 4, a is the fracture morphology of the p-type thermoelectric material obtained in Example 4; b is the fracture morphology of the p-type thermoelectric material obtained in Example 1; c is the fracture morphology of the n-type thermoelectric material obtained in Example 4; d is the fracture morphology of the n-type thermoelectric material obtained in Example 1.
[0166] Figure 6The thermoelectric performance test results of p-type and n-type thermoelectric materials obtained in Examples 1, 4, and 5 of the present invention are shown. Materials a, c, and e represent p-type materials, while materials b, d, and f represent n-type materials. The figure shows that for p-type samples, changes in annealing temperature have little effect on κ. However, for n-type samples, lower annealing temperatures help reduce the κ value of the printed samples.
[0167] The κtot of p-type and n-type samples ranges from 0.6 to 1 W m-1 over the entire measurement temperature range. -1 K -1 and 0.5-0.7W m -1 K -1 significantly lower than the traditional ZM samples (1.2-2.5W m -1 K -1 )
[0168] Figure 7 These are the thermoelectric performance test results of p-type and n-type thermoelectric materials obtained in Examples 1, 6, and 7 of the present invention, where a, c, and e are p-type thermoelectric materials, and b, d, and f are n-type thermoelectric materials.
[0169] As can be seen from the figure, for p-type samples, the change of annealing temperature has no obvious effect on κ, but for n-type samples, a lower annealing temperature helps to reduce the κ value of the printed sample.
[0170] The κtot of p-type and n-type samples ranges from 0.6 to 1 W m-1 over the entire measurement temperature range. -1 K -1 and 0.5-0.7W m -1 K -1 significantly lower than the traditional ZM samples (1.2-2.5W m -1 K -1 ).
[0171] For both p- and n-type samples, a lower annealing temperature (460-480°C) is beneficial for obtaining a higher ZT value, where the p-type sample has the maximum ZT at 325K. max The value reaches 1.3, and the n-type sample has the maximum ZT at 450K max The value reaches 1.1.
[0172] This paper uses a quasi-inorganic thermoelectric ink formulation to produce high-performance p-type and n-type Bi2Te3-based thermoelectric samples using DIW printing. Optimized heat treatment further enhances thermoelectric properties, effectively addressing the challenge of low performance in bismuth telluride materials. By creating a large number of nano- and micro-scale pores, which enhance phonon scattering and thus reduce lattice thermal conductivity, and by increasing the effective mass of carrier state density to improve the Seebeck coefficient, excellent thermoelectric performance is achieved through synergistic regulation.
Claims
1. A method for preparing a water-based bismuth telluride ink, characterized in that: The following steps are involved: Step 1: Weigh the raw materials according to the set chemical formula atomic ratio, ball mill, grind, disperse and sieve to obtain raw material powder; Step 2: adding the polyvinyl pyrrolidone solution dropwise to the methyl cellulose solution to obtain solution A; the mass ratio of the polyvinyl pyrrolidone to the methyl cellulose is 1-4:1-5; Step 3: adding solution A dropwise to the polyethyleneimine solution and mixing thoroughly, and then adding a solvent dropwise to obtain solution B; the mass ratio of the polyethyleneimine to the methylcellulose is 0.5-2:1-5; Step 4: Add the raw material powder in step 1 to solution B, stir and disperse to obtain the required ink; the mass of the organic matter accounts for 0.45% to 0.65% of the mass of the raw material powder; the organic matter is the total mass of polyvinyl pyrrolidone, methyl cellulose, polyethyleneimine and solvent.
2. The method for preparing a water-based bismuth telluride ink according to claim 1, characterized in that: The solvent is obtained by mixing dimethylformamide and polyacrylic acid in a molar ratio of 1:
2.
3. The method for preparing a water-based bismuth telluride ink according to claim 1, wherein: In step 4, dispersion is performed by a centrifuge, the centrifuge speed is 400 rpm, and the dispersion time is 1 hour.
4. The use of a water-based bismuth telluride ink obtained by any one of the preparation methods of claims 1 to 3, characterized in that: The water-based bismuth telluride ink is used to prepare p-type or n-type Bi2Te3-based thermoelectric materials.
5. The use of a water-based bismuth telluride ink according to claim 4, characterized in that: The Bi2Te3-based thermoelectric material is n-type Bi2Te 2.6 Se 0.4 and p-type Bi 0.5 Sb 1.5 Te3.
6. A method for preparing Bi2Te3-based thermoelectric materials, characterized in that The following steps are involved: S1: 3D printing a Bi2Te3-based thermoelectric material body using a water-based bismuth telluride ink obtained by any preparation method according to claims 1 to 3; S2: Annealing the green body in step S1 to obtain the desired Bi2Te3-based thermoelectric material.
7. The method for preparing a Bi2Te3-based thermoelectric material according to claim 6, characterized in that: The 3D printing in step S1 is DIW printing.
8. The method for preparing a Bi2Te3-based thermoelectric material according to claim 6, characterized in that: The printing conditions are as follows: a printing rate of 6 to 20 mm / s, a filling spacing of 0.35 to 0.45 mm, a printing layer height of 0.38 to 0.48 mm; and an air pressure of 0.1 to 0.4 MPa during printing.
9. The method for preparing a Bi2Te3-based thermoelectric material according to claim 6, characterized in that: Before the annealing in step S2, heating and drying are first performed, and the drying system is as follows: Keep warm at 25℃ for 12h, at 50℃ for 5h, at 70℃ for 12h, and at 90℃ for 5h.
10. The method for preparing a Bi2Te3-based thermoelectric material according to claim 6, characterized in that: In step S2, the annealing temperature is 460-500° C., and the annealing time is 60-180 minutes.