Skin-core structure moisture power generation yarn, preparation method and application of skin-core structure moisture power generation yarn

Abstract

The invention provides a skin-core structure moisture power generation yarn, the yarn at least comprises a metal core layer, a wrap yarn layer and a conductive coating, the wrap yarn layer comprises lithium chloride doped polyvinyl alcohol fibers and tightly wraps the periphery of the metal core layer through conjugate electrostatic spinning, and the conductive coating is nano conductive silver paint. And the conductive coating is not in direct contact with the metal core layer. The preparation method comprises the following steps: firstly, adding lithium chloride powder into deionized water, stirring at normal temperature until complete dissolution, then adding polyvinyl alcohol powder, heating and stirring until complete dissolution, standing and defoaming to prepare a wrap yarn layer spinning solution; performing conjugate electrostatic spinning on the prepared skin layer spinning solution to form nanofiber wrap yarn on the outer layer of the metal core; nano conductive silver paint is sprayed on the surface of the wrap yarn layer, and the wrap yarn layer is dried in the air. The yarn has good flexibility, and has excellent surface waterproof and moisture permeable performance, stability and reusability while forming stable output current and voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power generation devices, in particular to a core-sheath structure moisture power generation device and a preparation method thereof. BACKGROUND

[0002] With the rapid development of flexible electronic devices and smart textiles, miniaturized and self-powered energy technology has become a key breakthrough for industrial upgrading. Traditional rigid batteries are limited by their large size, environmental pollution, and the need for frequent charging, making it difficult to meet the needs of wearable devices for lightweight, flexibility, and long-term stable power supply. Although the moisture power generation (MEG) technology can directly generate electricity using environmental humidity differences, it has long been plagued by material structure and manufacturing process bottlenecks. Current mainstream MEG devices mostly use thin film or homogeneous fiber structures, which have inherent contradictions between moisture absorption and electrical conductivity. High moisture absorption materials have low ion mobility, and conductive materials lack humidity response capability, resulting in low power generation efficiency. In addition, humidity fluctuations often cause more than 50% output decay, and performance loss exceeds 80% after 100 repeated bends. The weak interfacial bonding force of the nano-coating process makes it impossible to produce continuous kilometers of yarn, and thin film devices are difficult to integrate into textiles due to the loss of air permeability.

[0003] In existing core-sheath structure moisture power generation related research, although high voltage and current output can be achieved, and even a watch can be driven normally by connecting several fibers in series and parallel, such fibers have significant drawbacks. First, the fiber diameter is relatively large, resulting in poor weavability and difficulty in adapting to the weaving integration needs of smart textiles. Second, the external electrode is easily oxidized and corroded by external water molecules and air, leading to a decline in electrical and mechanical properties. Third, the continuous power generation time needs to be further improved. These problems make it difficult to apply to wearable smart textiles, and a more optimal technical solution is needed to overcome these limitations. SUMMARY

[0004] To solve the problems in the prior art, the present application designs a core-sheath structure moisture power generation yarn, using a metal wire as a core electrode, covering the metal wire surface with nanofibers through conjugated electrospinning, and spraying a conductive coating outside the fiber layer to prevent oxidation. The nanofiber coated yarn has good flexibility, stable output current and voltage, and excellent surface waterproof and moisture permeability.

[0005] To achieve the above technical purposes, the present application provides a core-sheath structure moisture power generation yarn, which comprises at least a metal core layer, a coated yarn layer, and a conductive coating layer. The coated yarn layer comprises lithium chloride doped polyvinyl alcohol fibers, which are tightly wrapped around the metal core layer through electrospinning. The conductive coating layer is a nanometer conductive silver paint, and the conductive coating layer does not directly contact the metal core layer.

[0006] In some technical solutions of the present application, the conductive metal wire is one of zinc wire and aluminum wire. Preferably, the conductive metal wire is selected from zinc wire.

[0007] In some technical solutions of the present application, the diameter of the lithium chloride-doped polyvinyl alcohol fiber of the wrapping yarn layer is 270-320 nm.

[0008] In some technical solutions of the present application, the thickness of the wrapping yarn layer is 30-50 μm.

[0009] In some technical solutions of the present application, the wrapping rate of the wrapping yarn layer outside the metal core layer is not less than 40%; and the calculation formula of the wrapping rate is as follows:

[0010]

[0011] In the formula, n represents the wrapping rate of the nanofiber in the nanofiber wrapping yarn; m1 represents the gram weight of the nanofiber wrapping yarn after conjugate electrospinning at different LiCl concentrations, g; and m0 represents the gram weight of the zinc metal wire of the core layer, g. Too low wrapping rate of the wrapping yarn layer outside the metal core layer will affect the humidity power generation efficiency.

[0012] In some technical solutions of the present application, the water contact angle of the yarn outer surface is 110°-120°, which ensures that the yarn has certain hydrophobicity and also guarantees the humidity power generation performance, and the waterproof and moisture-permeable performance provides important support for the application of water power generation.

[0013] The present application also provides a preparation method of the skin-core structure humidity power generation yarn, which at least comprises the following steps:

[0014] Step 1: adding lithium chloride powder into deionized water, stirring at room temperature until completely dissolved, then adding polyvinyl alcohol powder into the lithium chloride deionized water solution, heating and stirring until completely dissolved, and keeping warm and standing for defoaming to prepare a wrapping yarn layer spinning solution;

[0015] Step 2: forming a nanofiber wrapping yarn outside the metal core by conjugate electrospinning of the prepared skin layer spinning solution;

[0016] Step 3: spraying a nanometer conductive silver paint on the surface of the wrapping yarn layer, and drying in air to prepare the humidity power generation yarn.

[0017] In some technical solutions of the present application, the mass concentration of polyvinyl alcohol in the wrapping yarn layer spinning solution in step 1 is 6-12%, and preferably the mass concentration of polyvinyl alcohol is 10%.

[0018] In some embodiments of the present application, the mass concentration of lithium chloride in the coating yarn layer spinning solution in step 1 is 0.01-0.6%, and specific examples include 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%, and preferably, the mass concentration of lithium chloride is 0.2-0.4%. Although increasing the concentration of lithium chloride can increase the hydrophilicity of the coating yarn layer, the addition of lithium chloride also has an important influence on the morphology of the electrospun fibers. When the concentration of lithium chloride increases to 0.2%, the polyvinyl alcohol fibers become finer and more densely arranged, but when the content further increases to more than 0.4%, beaded structures appear on the surface of the fibers, and the fibers have irregular bending morphologies and the fiber diameter begins to increase; when the addition amount exceeds 0.6%, the viscosity of the spinning solution is too high, the spinning jet is unstable, and the spinning solution breaks.

[0019] In some embodiments of the present application, the dissolving process of polyvinyl alcohol in step 1 is as follows: the solvent temperature is 80-90°C, the stirring speed is 300-600 rpm, and the stirring time is 1-3 h. Preferably, the dissolving temperature is 85°C, and the stirring speed is 400 rpm.

[0020] In some embodiments of the present application, the conjugate electrospinning in step 2 mainly includes the following steps:

[0021] Step a1, the coating yarn layer spinning solution is loaded into two syringes with metal needles and installed on a syringe pump, and the syringe needles are symmetrically arranged on a plastic funnel;

[0022] Step a2, the needles are respectively connected to two opposite polarity high-voltage power supplies;

[0023] Step a3, using a metal wire as a core layer, under the action of two parallel separated opposite polarity high static voltage and rotating plastic funnel, the spinning forms a Taylor cone and sprays nanofibers towards the rotating funnel, and at the same time, the nanofibers are twisted on the core wire by a certain speed of the plastic funnel, forming a coating yarn layer outside the metal core layer.

[0024] In some preferred embodiments of the present application, the inner diameter of the metal needle used in step a1 of the conjugate electrospinning is 0.33 mm.

[0025] In some preferred embodiments of the present application, the spinning process in step a3 includes: the injection pump pushing rate is 0.2-0.8 mL / h, the distance between the needle tip and the plastic funnel is 10-18 cm, the positive and negative high-voltage power supplies are ±6-10 KV, respectively, the plastic funnel rotating speed is 80-200 r / min, and the coating yarn collection speed is 0.01-0.5 r / min.

[0026] In some technical solutions of the present application, the nano-conductive silver paint spraying process in step 3 is: the spraying distance is 15-30 cm, and the drying time is 1 h.

[0027] The present application also provides an application of the core-sheath structure moisture power generation yarn, which can be applied to prepare a self-power generation power source, the metal core layer of the yarn acts as a negative electrode of the power source, and the conductive coating layer acts as a positive electrode of the power source. The present application can also be used in flexible wearable devices and water power generation devices.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The present application uses polyvinyl alcohol as the sheath layer base resin, which has good moisture absorption performance. When the moisture in the environment is absorbed by the PVA, a large number of mobile charged ions are generated by the dissociation of oxygen-containing functional groups, forming an ion concentration gradient. Subsequently, these ions will migrate along the direction of the ion concentration gradient, resulting in a potential difference between the two electrodes, thereby inducing voltage output. Further, the addition of lithium chloride in the sheath layer can absorb moisture in the air to form hydrates, promote the moisture absorption performance of the sheath layer, and at the same time form a solution to release ions, further improve the current intensity, which can reach a level of about 34 mu A.

[0030] 2. The present application prepares a coated yarn layer wrapped around the metal core layer by means of conjugate electrospinning of polyvinyl alcohol / lithium chloride solution, and sprays a conductive silver coating on the surface of the coated yarn layer. The time of continuously outputting current and voltage under 95% RH and 25 DEG C can reach 10000s and above, and the silver particle spraying treatment effectively improves the water resistance and moisture permeability of the yarn, so that it can realize stable and efficient voltage and current output in different water environments. In seawater, the current increases to 0.41mA, the water flow speed increases from 0 to 600rpm, the voltage and current output show an obvious increasing trend, the maximum voltage output is close to 0.6V, and the current reaches about 0.7mA, showing good water power generation potential, and also having stability and reusability.

[0031] 3. The present application can use the preparation method of conjugate electrospinning, which is simple and can realize continuous production. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1A schematic diagram of the core-sheath structure yarn prepared in the embodiment of the present application is shown in the figure, wherein 1 represents a metal core layer, 2 represents a wrapping yarn layer, and 3 represents a conductive coating layer.

[0034] Figure 2 A cross-sectional electron microscope image of the core-sheath structure power generation yarn prepared in the embodiment 1 of the present application is shown in the figure.

[0035] Figure 3 A schematic diagram of the process of preparing the core-sheath structure power generation device in the present application is shown in the figure.

[0036] Figure 4 A voltage output test diagram of the duration of the embodiment 1 is shown in the figure.

[0037] Figure 5 A voltage output test diagram of the embodiment 1 before and after drying in the water power generation is shown in the figure. DETAILED DESCRIPTION

[0038] The technical solutions in the present application will be described clearly and completely in combination with the embodiments in the present application. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0039] The materials used in the embodiments of the present application are all commercially available, as shown in the following table.

[0040] Name Specification Polyvinyl alcohol Degree of polymerization: 1799 Zinc wire 99.9％ Lithium chloride monohydrate AR Sprayed silver AR Deionized water Conductivity: 2 μS / cm

[0041] Embodiment 1

[0042] 0.1 g of lithium chloride powder was added into 44.9 g of deionized water, and stirred at room temperature until completely dissolved. Then, 5 g of polyvinyl alcohol powder was added into the deionized water solution of 45 g of lithium chloride, heated at 85°C, and stirred at a speed of 400 rpm until completely dissolved, and then kept and placed for defoaming, to prepare a skin layer spinning solution for standby use.

[0043] The prepared skin layer spinning solution was loaded into two syringes with metal needles (inner diameter of needle: 0.33 mm) and installed on a syringe pump, and the pushing rate of the syringe pump was set to 0.5 mL / h. The syringe needles were symmetrically arranged on a plastic funnel, and the distance between the needle tips and the plastic funnel was 15 cm. The needles were respectively connected to two opposite polarity high voltage power supplies, which were respectively set to ±7KV. Zinc wire was used as the core layer, and under the action of two parallel separated opposite polarity high static voltage and rotating plastic funnels, the spinning formed Taylor cone and sprayed nanofibers towards the rotating funnel, while the nanofibers were twisted on the core yarn through a plastic funnel with a certain rotating speed (rotating speed was 100 r / min), to form LiCl / PVA nanofiber wrapping yarn, and the wrapping yarn collection speed was 0.02 r / min.

[0044] A layer of nano-conductive silver paint was sprayed 20 cm from the surface of the nanofiber wrap yarn, and dried in air for 1 h to prepare the moisture power generation yarn.

[0045] The test showed that the coverage rate of the wrap yarn layer of Example 1 was 65%.

[0046] Example 2 was compared with Example 1, and the only difference was that the amount of lithium chloride powder added was 0.2 g. The test showed that the coverage rate of the wrap yarn layer of Example 2 was 60%.

[0047] Example 3 was compared with Example 1, and the only difference was that the amount of lithium chloride powder added was 0.3 g. The test showed that the coverage rate of the wrap yarn layer of Example 2 was 40%.

[0048] Comparative Example 1: Compared with Example 1, the difference was that no lithium chloride powder was added. The test showed that the coverage rate of the wrap yarn layer of Example 2 was 78%.

[0049] Comparative Example 2: Compared with Example 1, the difference was that the amount of lithium chloride powder added was 0.4 g. During the spinning process of Comparative Example 2, it was found that the viscosity of the spinning solution was too high, the fibers were mutually adhered, and phenomena such as spinning rupture and beading occurred, and a complete wrap yarn layer could not be formed.

[0050] Test experiment:

[0051] 1. Hydrophilic contact angle: The hydrophilicity of the nanofiber wrap yarn and the surface after spraying silver particles was tested by using the SDC-350 contact angle measuring instrument of Dongguan Shengding Precision Instrument Co., Ltd.

[0052] 2. Current and voltage test: The electrical properties of Examples 1-3 and Comparative Examples were measured under different relative humidities and underwater by using the DM7510 digital multimeter of Tektronix Technology Co., Ltd. The relative humidity was controlled to be 95% by using saturated Na2SO4 solution, and the temperature was 24-27°C.

[0053] Underwater test is to immerse the sample (Examples 1-3 and Comparative Examples) to be tested in a container containing different types of water, and place the container on a magnetic stirring device. The multimeter is connected to the two poles of the sample, and the electrical properties under different water sources and different water flow rates are tested.

[0054] Test results:

[0055] 1. Hydrophilic contact angle: The water contact angle test of Examples 1-3 all reached more than 110°, and all had certain hydrophobicity.

[0056]

[0057] 2. Electrical property test:

[0058] Table 1 Voltage and current output of examples and comparative examples in 95% RH

[0059] Example 1 Example 2 Example 3 Comparative Example 1 Short-circuit current (μA) 34 31 22 0 Open-circuit voltage (V) 0.78 0.76 0.75 0.55

[0060] As can be seen from the above table, the short-circuit current and open-circuit voltage of the LiCl-doped sample are both significantly better than those of the undoped sample, indicating that the introduction of LiCl has a positive effect on improving the humidity response capability. When the lithium chloride doping concentration is 0.2%, the output current is the highest and can reach 34 μΑ, but the effect of lithium chloride doping concentration on voltage is not very significant. In addition, the continuous power generation performance of the sample of Example 1 was tested, and the results are shown in Figure 4 As can be seen from the above table, the short-circuit current and open-circuit voltage of the LiCl-doped sample are both significantly better than those of the undoped sample, indicating that the introduction of LiCl has a positive effect on improving the humidity response capability. When the lithium chloride doping concentration is 0.2%, the output current is the highest and can reach 34 μΑ, but the effect of lithium chloride doping concentration on voltage is not very significant. In addition, the continuous power generation performance of the sample of Example 1 was tested, and the results are shown in

[0061] Table 2 Water power generation performance of examples and comparative examples

[0062]

[0063] As can be seen from Table 2, the examples can output voltage and current signals under different water sources, and the stable voltage change is not obvious; in terms of short-circuit current, the short-circuit current in seawater can reach 410 μΑ. Further tests of the output current and voltage of Example 1 under different water flow rates showed that when the water flow rate was further increased, the current and voltage would further show an increasing trend. In a seawater environment, as the water flow rate increased, the voltage could further increase by about 13%, and the current could increase by about 70%. Water flow rate could also have a positive regulating effect on the electrical output performance of the sample.

[0064] To further verify the stability and reusability of the sample, the humidity power generation electrical output performance of the sample of Example 1 was tested before and after drying after the water power generation experiment (results are shown in Figure 5 It was found that after soaking and drying cycles in a water environment, the sample could still maintain good power generation performance and structural integrity, and had high reusability and environmental adaptability.

[0065] Finally, it should be noted that, although the present application has been described in detail above with the general description and the specific embodiments, the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail above with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A core-sheath structure moisture power generating yarn, characterized by, The yarn comprises at least a metal core layer, a wrapping yarn layer and a conductive coating layer; the wrapping yarn layer comprises lithium chloride-doped polyvinyl alcohol fibers, which are tightly wrapped around the metal core layer by electrospinning; and the conductive coating layer is a nano-conductive silver paint, which is not in direct contact with the metal core layer.

2. The core-sheath structure moisture power generation yarn according to claim 1, wherein the conductive metal wire is one of zinc wire and aluminum wire; the lithium chloride-doped polyvinyl alcohol fiber of the wrapping yarn layer has a diameter of 270-320 nm; and the water contact angle of the outer surface of the yarn is 110-120°.

3. A method of producing a core-sheath structure moisture power generating yarn according to claim 1, characterized in that, The method comprises at least the following steps: Step 1: adding lithium chloride powder into deionized water, stirring at room temperature until completely dissolved, then adding polyvinyl alcohol powder into the lithium chloride deionized water solution, heating and stirring until completely dissolved, and then keeping still to remove bubbles, to prepare a wrapping yarn layer spinning solution; Step 2: preparing the prepared sheath layer spinning solution by conjugate electrospinning to form a nano-fiber wrapping yarn on the outer layer of the metal core; Step 3: spraying a nano-conductive silver paint on the surface of the wrapping yarn layer, and then air-drying to obtain the moisture power generation yarn.

4. The production method according to claim 3, characterized by, In step 1, the mass concentration of polyvinyl alcohol in the wrapping yarn layer spinning solution is 6-12%, and the mass concentration of lithium chloride in the wrapping yarn layer spinning solution is 0.01-0.6%.

5. The preparation method according to claim 3, characterized in that, The conjugate electrospinning in step 2 mainly comprises the following steps: Step a1: loading the wrapping yarn layer spinning solution into two injectors with metal needles and mounting the injectors on an injection pump, and symmetrically arranging the needle tips of the injectors on a plastic funnel; Step a2: connecting the needle tips to two opposite-polarity high-voltage power supplies; Step a3: using a metal wire as a core layer, under the action of two parallel separated opposite-polarity high static voltage and a rotating plastic funnel, the spinning forms a Taylor cone and sprays the nano-fiber towards the rotating funnel, while the plastic funnel with a certain rotating speed twists the nano-fiber on the core wire to form a wrapping yarn layer on the outer periphery of the metal core layer.

6. The production method according to claim 5, wherein The inner diameter of the metal needle used in the conjugate electrospinning in step a1 is 0.33 mm.

7. The preparation method according to claim 5, characterized in that, The spinning process in step a3 comprises: the injection pump has a pushing rate of 0.2-0.8 mL / h, the distance between the needle tip and the plastic funnel is 10-18 cm, the positive and negative high-voltage power supplies are ±6-10 KV respectively, the rotating speed of the plastic funnel is 80-200 r / min, and the wrapping yarn collection speed is 0.01-0.5 r / min.

8. The preparation method according to claim 3, characterized in that, In step 3, the nano-conductive silver paint spraying process comprises: a spraying distance of 15-30 cm and a drying time of 1 h.

9. Use of a core-sheath structure moisture power generating yarn, characterized in that, The yarn can be applied to prepare a self-generating power source, a flexible wearable device and a water power generation device.

10. Use of a core-sheath structured moisture power generating yarn according to claim 9, characterized in that, The metal core layer of the yarn serves as a negative electrode of the power source of the power generation device, and the conductive coating layer serves as a positive electrode of the power source.

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