A method for preparing PN-type alternating flexible thermoelectric fibers

Abstract

This invention relates to the field of materials science and technology, specifically a method for preparing P-N type alternating flexible thermoelectric fibers. The method involves adding polyvinyl alcohol (PVA) powder with a molecular weight of 25,000-300,000 to deionized water and stirring at 85°C until the solution becomes clear, thus preparing a 10%wt PVA solution. Then, 0.01-2g of P-type thermoelectric material powder and 10g of the 10%wt PVA solution are added to 100-500ml of deionized water. For thermoelectric materials with poor dispersibility, 100mg of dispersant is added. The mixture is ultrasonicated for 10-60 minutes, then heated and stirred to fully mix and concentrate to 10-20g, obtaining a mixture of P-type thermoelectric material and PVA solution. Finally, 0.01-2g of N-type thermoelectric material powder and 10g of the 10%wt PVA solution are added to the PVA solution. Add PVA solution to 100-500 ml of deionized water, sonicate the mixture for 10-60 min, then heat and stir to fully mix the mixture and concentrate it to 10-20 g to obtain a mixture of N-type thermoelectric material and PVA solution. The preparation method in this application is suitable for large-scale production, with uniform and stable thermoelectric properties, and the performance will not decrease due to the detachment of thermoelectric material caused by bending or friction.

Description

Technical Field

[0001] This invention relates to the field of materials science and technology, specifically a method for preparing PN-type alternating flexible thermoelectric fibers. Background Technology

[0002] With continuous breakthroughs in miniaturization and integration of electronic devices, wearable electronic devices and smart fabrics are receiving increasing attention. Thermoelectric materials can directly convert heat energy into electrical energy and can be applied in wearable electronic devices for touch sensing, detection and monitoring, body temperature regulation, and energy harvesting.

[0003] The performance of thermoelectric materials is typically evaluated using the thermoelectric figure of merit (ZT) and power factor (PF), given by the formulas ZT = σS²T / κ and PF = σS², where S is the Seebeck coefficient, σ is the electrical conductivity, T is the temperature, and κ is the thermal conductivity. A higher ZT value indicates a stronger ability to convert thermal energy into electrical energy, and thus better thermoelectric performance.

[0004] Currently, commercially available thermoelectric materials are mainly rigid solid bulk materials. The fabrication of thermoelectric fibers primarily involves adding a thermoelectric material coating with thermoelectric properties to the surface of already flexible fibers. However, methods such as coating ordinary fibers with thermoelectric materials or filling the gaps in fabrics to create thermoelectric fibers are inefficient in terms of space utilization. Furthermore, friction and deformation caused by body movement inevitably wear down the attached thermoelectric material, reducing its performance. Simultaneously, achieving the continuous alternation of P-type and N-type thermoelectric regions remains a challenge. Summary of the Invention

[0005] The purpose of this invention is to solve the existing problems and provide a method for preparing PN-type alternating flexible thermoelectric fibers.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing PN-type alternating flexible thermoelectric fibers, characterized by comprising the following steps:

[0008] Step 1: Take polyvinyl alcohol (PVA) powder with a molecular weight of 25,000-300,000, add it to deionized water, and stir at 85 degrees Celsius until the solution becomes clear to prepare a 10% wt PVA solution;

[0009] Step 2: Take 0.01-2g of P-type thermoelectric material powder and 10g of 10%wt PVA solution and add them to 100-500ml of deionized water. Sonicate the mixture for 10-60min, then heat and stir to fully mix the mixture and concentrate it to 10-20g to obtain a mixture of P-type thermoelectric material and PVA solution.

[0010] Step 3: Take 0.01-2g of N-type thermoelectric material powder and 10g of 10%wt PVA solution and add them to 100-500ml of deionized water. Sonicate the mixture for 10-60min, then heat and stir to fully mix the mixture and concentrate it to 10-20g to obtain a mixture of N-type thermoelectric material and PVA solution.

[0011] Step 4: Inject the P-type and N-type mixtures into the mold tubes respectively, freeze and then thaw to obtain P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel;

[0012] Step 5: P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel are alternately extruded into the mold tube, and the interface is healed by freezing to obtain P-type / N-type alternating thermoelectric gel;

[0013] Step 6: Dry the alternating P-type / N-type thermoelectric gel to obtain alternating P-type / N-type thermoelectric fibers;

[0014] Step 7: Apply adhesive to the fiber surface, and after drying, a waterproof and insulating layer will be formed on the surface.

[0015] As a preferred technical solution, the dispersant in step 2 is sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate.

[0016] As a preferred technical solution, in step 4, the mixture of P-type thermoelectric material and PVA solution and the mixture of N-type thermoelectric material and PVA solution are respectively injected into the mold tube, frozen at -5 to -50 degrees Celsius for 2-10 hours and then thawed to obtain P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel.

[0017] As a preferred technical solution, in step 5, one end of each of the two mold tubes containing P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel is connected to an injection pump, and the other end is alternately and tightly aligned with another tube under the control of a motor. When aligned, the gel is extruded under the action of the injection pump. This process is repeated to obtain alternating P-type and N-type thermoelectric gels.

[0018] As a preferred technical solution, in step 6, the adjacent gel segments are frozen at 0 to -50 degrees Celsius for 2 to 10 hours to allow them to heal together, and then extruded and dried at 20 to 80 degrees Celsius to obtain NP-type alternating thermoelectric fibers.

[0019] As a preferred technical solution, the inner diameter of the mold tube is 0.5-5mm.

[0020] As a preferred technical solution, N-type thermoelectric materials include bismuth selenide, tin sulfide, or single-walled carbon nanotubes.

[0021] As a preferred technical solution, P-type thermoelectric materials include zinc oxide, zinc selenide, bismuth telluride, or multi-walled carbon nanotubes.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The present invention discloses a method for preparing PN-type alternating flexible thermoelectric fibers, which has a simple process, low cost, and the P / N type alternating thermoelectric fibers are easy to manufacture industrially and are suitable for large-scale production.

[0024] 2. In this invention, the thermoelectric material is dispersed inside the thermoelectric fiber, resulting in uniform and stable thermoelectric performance. The thermoelectric material will not fall off due to bending or friction, thus preventing a decrease in performance.

[0025] 3. The P-type / N-type alternating thermoelectric fibers prepared in this invention have a tight bond at the PN interface, and the lengths of the P and N segments are controllable, making them suitable for weaving. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the fabrication process of the PN-type alternating thermoelectric fibers of the present invention.

[0027] Figure 2 The thermoelectric properties of the PN-type alternating flexible thermoelectric fiber of the present invention; Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] like Figure 1-2 As shown, a method for preparing a PN-type alternating flexible thermoelectric fiber is characterized by comprising the following steps:

[0031] Step 1: Take PVA powder with a molecular weight of 150,000, add it to deionized water, and stir at 85 degrees Celsius until the solution becomes clear to prepare a 10% wt polyvinyl alcohol (PVA) solution.

[0032] Step 2: Take 500mg of single-walled carbon nanotubes, 100mg of sodium dodecyl sulfonate (SDS), and 10g of 10%wt PVA solution and add them to 250ml of deionized water. Sonicate the mixture for 20min, then heat and stir to concentrate the mixture to 15g, to obtain a mixture of multi-walled carbon nanotubes and PVA solution.

[0033] Step 3: Take 500 mg of single-walled carbon nanotubes, 150 mg of polyethyleneimine, 100 mg of sodium dodecyl sulfonate (SDS), 10 g of 10% wt PVA solution, add them to 250 ml of deionized water, sonicate the mixture for 20 min, and then heat and stir to concentrate the mixture to 15 g, to obtain a mixture of polyethyleneimine-doped single-walled carbon nanotubes and PVA solution;

[0034] Step 4: The mixture of multi-walled carbon nanotubes and PVA solution and the mixture of polyethyleneimine-doped single-walled carbon nanotubes and PVA solution were extruded into mold tubes respectively, frozen at -20 degrees Celsius for 6 hours and then thawed to obtain P-type multi-walled carbon nanotube / PVA gel and N-type polyethyleneimine-doped single-walled carbon nanotube / PVA gel respectively.

[0035] Step 5: P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel are alternately extruded into the mold tube to obtain P-type and N-type alternating thermoelectric gels. Then, the interface is frozen at -20 degrees Celsius for 6 hours to heal, resulting in P-type / N-type alternating thermoelectric gels.

[0036] Step 6: Dry the alternating P-type / N-type thermoelectric gel to obtain alternating P-type / N-type thermoelectric fibers;

[0037] Step 7: Apply epoxy resin adhesive to the fiber surface, and after drying, a waterproof layer and an insulating layer will be formed on the surface.

[0038] Example 2:

[0039] like Figure 1-2 As shown, a method for preparing a PN-type alternating flexible thermoelectric fiber is characterized by comprising the following steps:

[0040] Step 1: Take PVA powder with a molecular weight of 98,000, add it to deionized water, and stir at 85 degrees Celsius until the solution becomes clear to prepare a 10% wt polyvinyl alcohol (PVA) solution.

[0041] Step 2: Add 500mg zinc oxide, 100mg sodium dodecyl sulfonate (SDS), and 10g 10%wt PVA solution to 250ml deionized water, sonicate the mixture for 20min, and then heat and stir to concentrate the mixture to 15g to obtain a mixture of zinc oxide and PVA solution.

[0042] Step 3: Add 500mg bismuth selenide, 100mg sodium dodecyl sulfate (SDS), 10g 10%wt PVA solution to 250ml deionized water, sonicate the mixture for 20min, and then heat and stir to concentrate the mixture to 15g to obtain a mixture of bismuth selenide and PVA solution.

[0043] Step 4: The mixture of zinc oxide and PVA solution and the mixture of bismuth selenide and PVA solution were extruded into the mold tubes respectively, frozen at -20 degrees Celsius for 6 hours and then thawed to obtain P-type zinc oxide / PVA gel and N-type bismuth selenide / PVA gel respectively.

[0044] Step 5: P-type zinc oxide / PVA gel and N-type bismuth selenide / PVA gel are alternately extruded into a mold tube to obtain P-type and N-type alternating thermoelectric gels. Then, the interface is frozen at -20 degrees Celsius for 6 hours to heal, resulting in P-type / N-type alternating thermoelectric gels.

[0045] Step 6: Dry the alternating P-type / N-type thermoelectric gel to obtain alternating P-type / N-type thermoelectric fibers;

[0046] Step 7: Apply polyvinyl alcohol adhesive to the fiber surface, and after drying, a waterproof and insulating layer will be formed on the surface.

[0047] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing PN-type alternating flexible thermoelectric fibers, characterized in that, Includes the following steps: Step 1: Take polyvinyl alcohol (PVA) powder with a molecular weight of 25,000-300,000, add it to deionized water, and stir at 85 degrees Celsius until the solution becomes clear to prepare a 10% wt PVA solution. Step 2: Take 0.01-2g of P-type thermoelectric material powder and 10g of 10%wt PVA solution and add them to 100-500ml of deionized water. Then add 100mg of dispersant. Sonicate the mixture for 10-60min, then heat and stir to fully mix the mixture and concentrate it to 10-20g to obtain a mixture of P-type thermoelectric material and PVA solution. Step 3: Take 0.01-2g of N-type thermoelectric material powder and 10g of 10%wt PVA solution and add them to 100-500ml of deionized water. Sonicate the mixture for 10-60min, then heat and stir to fully mix the mixture and concentrate it to 10-20g to obtain a mixture of N-type thermoelectric material and PVA solution. Step 4: Inject the P-type and N-type mixtures into the mold tubes respectively, freeze and then thaw to obtain P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel; Step 5: P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel are alternately extruded into the mold tube, and the interface is healed by freezing to obtain P-type / N-type alternating thermoelectric gel; Step 6: Dry the alternating P-type / N-type thermoelectric gel to obtain alternating P-type / N-type thermoelectric fibers; Step 7: Apply adhesive to the fiber surface, and after drying, a waterproof and insulating layer will be formed on the surface.

2. The method for preparing a PN-type alternating flexible thermoelectric fiber according to claim 1, characterized in that: The dispersant in step 2 is sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate.

3. The method for preparing a PN-type alternating flexible thermoelectric fiber according to claim 1, characterized in that: In step 4, the mixture of P-type thermoelectric material and PVA solution and the mixture of N-type thermoelectric material and PVA solution are respectively injected into the mold tube, frozen at -5 to -50 degrees Celsius for 2-10 hours and then thawed to obtain P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel.

4. The method for preparing a PN-type alternating flexible thermoelectric fiber according to claim 1, characterized in that: In step 5, one end of each of the two mold tubes containing P-type thermoelectric material / PVA gel and N-type thermoelectric material / PVA gel is connected to an injection pump, and the other end is alternately and tightly aligned with the other tube under the control of a motor. When aligned, the gel is extruded under the action of the injection pump. This process is repeated to obtain alternating P-type and N-type thermoelectric gels.

5. The method for preparing a PN-type alternating flexible thermoelectric fiber according to claim 3, characterized in that: The inner diameter of the mold tube is 0.5-5mm.

6. The method for preparing a PN-type alternating flexible thermoelectric fiber according to claim 3, characterized in that: The adhesive used in step 7 includes epoxy resin, latex, or silicone.

7. A method for preparing a PN-type alternating flexible thermoelectric fiber according to any one of claims 1-6, characterized in that: The N-type thermoelectric material includes bismuth selenide, tin sulfide, or single-walled carbon nanotubes.

8. A method for preparing a PN-type alternating flexible thermoelectric fiber according to any one of claims 1-6, characterized in that: The P-type thermoelectric material includes zinc oxide, zinc selenide, bismuth telluride, or multi-walled carbon nanotubes.

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