A multi-layer spiral structure moisture power generation yarn and a preparation method thereof

Abstract

This invention discloses a multi-layered spiral structure moisture-generating yarn and its preparation method. The generating yarn comprises, from the inside out, a spiral core yarn, an inner electrode layer, a covering yarn layer, and an outer electrode layer. Both the core yarn and the covering yarn layer contain hygroscopic salts and nanofiber membranes. The covering yarn layer covers the core yarn containing the inner electrode layer, preventing contact between the core yarn, the inner electrode layer, and the outer electrode layer. This multi-layered spiral structure moisture-generating yarn effectively resists erosion from humid and complex environments; it also meets the needs of knitting and weaving integration in smart textiles. Furthermore, it exhibits good output performance, with a maximum open-circuit voltage of 0.64V, and achieves a stable and continuous output signal for 50,000 seconds at 50% ambient humidity.

Description

Technical Field

[0001] This invention relates to the field of self-generating composite yarn technology, and in particular to a multi-layer spiral structure moisture-generating yarn and its preparation method. Background Technology

[0002] The demand for lightweight, flexible, and long-term stable power supply for wearable electronic devices is becoming increasingly urgent. Traditional chemical batteries have drawbacks such as poor flexibility and the need for frequent charging. However, wet gas power generation technology has become an important direction for solving the power supply problem of wearable devices due to its advantages of strong environmental adaptability and wide range of energy sources.

[0003] CN121065871A discloses a core-sheath structure moisture-generating yarn, its preparation method, and its application. This invention utilizes the hygroscopic properties of polyvinyl alcohol and the ion-enhancing effect of lithium chloride, combined with conjugated electrospinning technology and conductive coating protection design, to enable the device to achieve stable voltage and current output for 10,000 seconds or more under 95%RH and 25℃ conditions. However, the conductive coating of this method relies on nano-conductive silver paint, and the chemical stability of silver is limited. Long-term exposure to complex environments affects the electrode life.

[0004] Patent CN220132455U discloses a moisture-generating yarn and fabric. The yarn uses non-conductive yarn as the base and is covered with overlapping conductive materials in a cyclic pattern along its length. It generates electricity by absorbing moisture and dissociating ions through the moisture-generating materials to form a potential difference. It is flexible, lightweight, and weaveable, which can meet the fitting requirements of wearable devices. It can achieve high-density integration of the moisture-generating unit through weaving and has a wide applicable humidity range (20%-95%RH). However, its conductive material is formed by coating process, resulting in insufficient interfacial bonding between the conductive layer and the base, and the power generation performance of the device is low. The highest open-circuit voltage is about 1.28V, but the long-term continuous power generation capability has not been clearly verified. Summary of the Invention

[0005] The purpose of this invention is to design a moisture-generating yarn with a multi-layer spiral structure to effectively resist the erosion of environmental factors such as humidity and complex media, and to extend the service life of the moisture-generating yarn; at the same time, to make it adaptable to complex temperature and humidity fluctuation environments around the clock, so as to achieve sustainable power generation around the clock.

[0006] To achieve the above objectives, the present invention provides a multi-layer spiral structure moisture-generating yarn, which, from the inside out, comprises a core yarn in a spiral structure, an inner electrode layer, a covering yarn layer, and an outer electrode layer. Both the core yarn and the covering yarn layer contain hygroscopic salts and nanofiber membranes. The covering yarn layer is used to cover the core yarn with the inner electrode layer, so that the core yarn and the inner electrode layer do not come into contact with the outer electrode layer.

[0007] Hygroscopic salts possess both hygroscopic and ionic conductivity. When ambient humidity changes, the salts absorb or release water molecules, leading to alterations in their ionization level and ion mobility, thereby causing a regular change in resistance. The hygroscopic salt can be at least one of lithium chloride, sodium polystyrene sulfonate, or sodium salt of styrene-maleic anhydride copolymer. Preferably, it is lithium chloride.

[0008] Furthermore, the inner electrode layer is a metal wire wound around the outer surface of the core yarn.

[0009] Furthermore, the material of the metal wire is not strictly limited; for example, it can be copper wire, silver wire, gold wire, or alloy wire thereof. Preferably, it is copper wire.

[0010] Furthermore, the winding density of the conductive wire is 2-10 turns / cm.

[0011] Furthermore, the outer electrode layer is woven from carbon fiber.

[0012] Carbon fiber combines lightweight, high strength, high modulus, high temperature resistance, and corrosion resistance, effectively resisting the erosion of environmental factors such as humidity and complex media. It also has the advantages of being lightweight, flexible, and having good air and moisture permeability.

[0013] This invention also provides a method for preparing a multi-layered spiral structure moisture-generating yarn, comprising, Nonwoven fabric is soaked in a hygroscopic salt solution to obtain strip-shaped first and second nonwoven fabrics, wherein the length of the second nonwoven fabric is greater than that of the first nonwoven fabric. Electrospinning is performed on the upper and lower sides of the first and second nonwoven fabrics to form nanofiber membranes, thereby obtaining the core yarn precursor and the covering yarn layer, respectively. The core yarn precursor is processed into a core yarn with a spiral structure, an inner electrode layer is prepared on the surface of the core yarn, and then the core yarn with the inner electrode layer is covered with a covering yarn layer. An outer electrode layer is prepared on the surface of the covered yarn layer. The covered yarn prevents the core yarn and inner electrode layer from contacting the outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0014] Further, the mass concentration of the hygroscopic salt solution is 2%-12%. The solvent for the hygroscopic salt solution is not strictly limited; for example, it can be at least one of water, ethanol, acetone, etc. Preferably, the mass concentration of the hygroscopic salt solution is 8%-11%.

[0015] Furthermore, the spinning solution used in the electrospinning is a 5-20 wt% polyacrylonitrile solution. The electrospinning time is 10-50 min. Preferably, the electrospinning time is 25-35 min.

[0016] Preferably, the mass concentration of the polyacrylonitrile solution is 10-15 wt%. At this concentration, the electrospun nanofiber membrane is relatively continuous and can form a three-dimensional, layered, porous, and ordered multilayer structure, which improves the overall specific surface area and porosity. This allows ions to be loaded more evenly and move within and on the surface of the fibers, which is beneficial for moisture transport and charge transfer. At lower concentrations, the fibers are discontinuous and insufficient to serve as a moisture-absorbing layer and internal structure for stable output performance in the device; at higher concentrations, a nanofiber membrane cannot be formed.

[0017] It should be noted that the solvent for dissolving polyacrylonitrile is not strictly limited, and can be, for example, at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and acetone.

[0018] Furthermore, the external electrode is prepared by braiding, with a pull-out speed of 2-6 rpm during braiding.

[0019] Furthermore, the nonwoven fabric undergoes an oxidation treatment before use.

[0020] Oxidation treatment is a conventional treatment method for nonwoven fabrics. As an optional method, sodium hydroxide is first dissolved in deionized water, then anhydrous ethanol is added and mixed well. The mixture is then kept in a 60°C water bath until the temperature stabilizes. Finally, 30% hydrogen peroxide solution is added and then the nonwoven fabric is added. The ratio of nonwoven fabric, sodium hydroxide, deionized water, anhydrous ethanol, and 30% hydrogen peroxide solution is 1g:1g:10mL:40mL:15g.

[0021] The present invention also provides a self-powered energy source, comprising the aforementioned multi-layer spiral structure moisture-generating yarn.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The multi-layer spiral structure moisture-generating yarn of this invention can effectively resist the erosion of environmental factors such as humidity and complex media; at the same time, it is suitable for the knitting and weaving integration needs of smart textiles.

[0023] The multi-layer spiral structure moisture-generating yarn of this invention has good output performance, with a maximum open-circuit voltage of 0.64V. It can achieve a stable and continuous output signal for 50,000 seconds under 50% ambient humidity. Furthermore, thanks to the moisture gradient construction and high-efficiency conductivity of the multi-layer spiral structure, it can adapt to complex temperature and humidity fluctuation environments around the clock, enabling sustainable power generation in all weather conditions. At the same time, it can achieve a service life of 600 hours under humidity conditions within the range of 30-90%. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the structure of the multi-layer spiral structure moisture-generating yarn prepared according to the present invention is shown; Figure 2 The output voltage diagrams of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1-3 and Example 12 are shown; Figure 3 (a) Figure 3 (b) and 3(c) show scanning electron microscope images of the nanofiber membranes prepared in Examples 1, 4 and 5, respectively; Figure 4 Long-term output voltage diagrams of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 4 and 5 are shown. Figure 5 The long-term output voltage diagrams of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 6 and 7 are shown. Figure 6 The long-term output voltage diagrams of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 8 and 9 are shown. Figure 7 Long-term output voltage diagrams of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 10, and 11 are shown. Figure 8 The long-term output voltage and current of the multi-layer spiral structure moisture-generating yarn prepared in Example 1 are shown; Figure 9 The temperature and humidity changes in the actual application environment are shown; Figure 10 The output voltage variation curve of the multi-layer spiral structure moisture-generating yarn prepared in Example 1 is shown in a practical application environment; Explanation of reference numerals in the attached figures: 1. Core yarn; 2. Inner electrode layer; 3. Covering yarn layer; 4. Outer electrode layer. Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and 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.

[0028] Example 1 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0029] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 10% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 10 wt%; Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 30 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0030] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn 1. Copper wire is wound around the surface of the core yarn 1 at 10 turns / cm to prepare the inner electrode layer 2. Then, the core yarn 1 with the inner electrode layer 2 is covered with a covering yarn layer 3. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer 3 to form the outer electrode layer 4, resulting in the following: Figure 1 The multi-layered spiral structure moisture-generating yarn shown is shown.

[0031] Example 2 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0032] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 2% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 10 wt%; Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 30 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0033] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn. Copper wire is wound around the core yarn surface at 10 turns / cm to prepare an inner electrode layer. Then, the core yarn with the inner electrode layer is covered with a covering yarn layer. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer to form an outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0034] Example 3 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0035] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 6% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 10 wt%; Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 30 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0036] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn. Copper wire is wound around the core yarn surface at 10 turns / cm to prepare an inner electrode layer. Then, the core yarn with the inner electrode layer is covered with a covering yarn layer. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer to form an outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0037] Example 4 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0038] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 10% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 5 wt%; Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 30 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0039] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn. Copper wire is wound around the core yarn surface at 10 turns / cm to prepare an inner electrode layer. Then, the core yarn with the inner electrode layer is covered with a covering yarn layer. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer to form an outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0040] Example 5 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0041] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 10% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 20 wt%. Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 30 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0042] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn. Copper wire is wound around the core yarn surface at 10 turns / cm to prepare an inner electrode layer. Then, the core yarn with the inner electrode layer is covered with a covering yarn layer. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer to form an outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0043] Example 6 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0044] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 10% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 10 wt%. Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 10 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0045] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn. Copper wire is wound around the core yarn surface at 10 turns / cm to prepare an inner electrode layer. Then, the core yarn with the inner electrode layer is covered with a covering yarn layer. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer to form an outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0046] Example 7 A method for preparing a multi-layered spiral structure moisture-generating yarn includes the following steps: S1. Pretreatment of cotton nonwoven fabric: First, dissolve 20g of sodium hydroxide in 200ml of deionized water, add 800ml of anhydrous ethanol, mix well, and keep warm in a 60℃ water bath until the temperature stabilizes. Add 30g of 30% hydrogen peroxide solution and put it into the cotton nonwoven fabric. After sealing, treat in a 60℃ water bath until the cotton nonwoven fabric turns white. Finally, rinse with deionized water until neutral, dry, and cut into multiple strips of 2cm×10cm and 2cm×15cm.

[0047] S2. Preparation of lithium chloride-loaded cotton nonwoven fabric: Prepare a 10% lithium chloride aqueous solution, immerse the long strip of cotton nonwoven fabric obtained in S1 in it, and after 12 hours, take it out and dry it to obtain a shorter first nonwoven fabric and a longer second nonwoven fabric. S3. Preparation of core yarn precursor and covering yarn layer: Polyacrylonitrile with a molecular weight of 85,000 was dissolved in N,N-dimethylacetamide and stirred at room temperature until completely dissolved to obtain a spinning solution with a mass fraction of 10 wt%; Electrospinning was performed on the upper and lower sides of the first and second nonwoven fabrics using a handheld electrospinning instrument for 50 min to form nanofiber membranes, thereby obtaining the core yarn precursor and covering yarn layer respectively.

[0048] S4. Assembly of the device: The core yarn precursor is twisted into a spiral core yarn. Copper wire is wound around the core yarn surface at 10 turns / cm to prepare an inner electrode layer. Then, the core yarn with the inner electrode layer is covered with a covering yarn layer. Finally, the weaving speed is fixed and the pull-out speed is adjusted to 4 rpm. Carbon fiber is woven on the surface of the covering yarn layer to form an outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

[0049] Example 8 The difference compared to Example 1 is that the copper wire is wound at 2 turns / cm.

[0050] Example 9 The difference compared to Example 1 is that the copper wire is wound at 6 turns / cm.

[0051] Example 10 The difference compared to Example 1 is that the pull-out speed during weaving is 2 rpm.

[0052] Example 11 The difference compared to Example 1 is that the pull-out speed during weaving is 6 rpm.

[0053] Example 12 The difference compared to Example 1 is that the concentration of the lithium chloride aqueous solution is 12%.

[0054] Test case The output voltage of the multilayer spiral structure moisture-generating yarns prepared in Examples 1-3 and Comparative Example 1 was tested at 50% RH, and the results are as follows: Figure 2 As shown, a 10% lithium chloride aqueous solution is beneficial for generating a higher output voltage. At a concentration of 10%, the Li⁺ loading reaches the adsorption limit of the cotton nonwoven fabric, fully combining with the active groups on the fiber surface and inside. After moisture adsorption, sufficient and uniformly distributed Li⁺ can be dissociated, forming the highest ion concentration gradient. However, when the concentration is below 10%, the number of dissociated Li⁺ and Cl⁻ is limited, and it is impossible to form a sufficiently strong ion concentration gradient inside the device. When the concentration is above 10%, the excess Li⁺ produces an "ion crowding effect" in the limited channel, causing mutual collisions and interference, a significant decrease in directional migration rate, an increase in transmission resistance, and a decrease in voltage. In addition, excessive wetting reduces the electrical contact performance with the electrode, further depleting the voltage.

[0055] The microstructure of the nanofiber membranes prepared in Examples 1, 4, and 5 was tested using scanning electron microscopy, as shown in Figure 3(a). Figure 3 As shown in (b) and 3(c), electron microscopy reveals that spherical droplets adhere to the nanofiber matrix electrospun from a 5 wt% polyacrylonitrile solution, resulting in a discontinuous fiber structure that is insufficient to serve as a moisture-absorbing layer and internal structure for stable output performance. The nanofibers electrospun from a 10 wt% polyacrylonitrile solution form a three-dimensional, layered, porous, and ordered multilayer structure, which increases the overall specific surface area and porosity of the fiber, allowing ions to be loaded more evenly and move within and on the surface of the fiber, thus facilitating moisture transport and charge transfer. The nanofibers electrospun from a 20 wt% polyacrylonitrile solution cannot form a nanofiber membrane.

[0056] The long-term output voltage of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 4, and 5 was tested at 50% RH. Figure 4As shown, Example 1 has a higher output voltage, which is consistent with the results of scanning electron microscopy characterization analysis.

[0057] The long-term output voltage of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 6, and 7 was tested at 50% RH. Figure 5 As shown, Example 1 exhibits a higher output voltage. This is because after 10 minutes of electrospinning, the nanofiber membrane cannot completely cover the lithium chloride-loaded cotton nonwoven fabric (LiCl-cotton). A large amount of lithium chloride is exposed on the surface of the LiCl-cotton. During moisture adsorption, Li⁺ is easily lost through moisture penetration, resulting in a reduction in the total number of mobile ions inside the device and an inability to form a stable ion concentration gradient, leading to a lower voltage. After 30 minutes of electrospinning, the nanofiber membrane completely covers the surface of the LiCl-cotton, reducing the Li⁺ loss rate and stabilizing the ion supply. Simultaneously, the nanopores are evenly distributed, ensuring rapid moisture penetration while retaining moisture through the "capillary effect" of the pores, maintaining the humid environment required for ion migration, thus resulting in the highest voltage. After 50 minutes of electrospinning, a large number of nanopores are blocked, forming a "physical barrier": ambient moisture cannot easily penetrate into the interior of the LiCl-cotton, LiCl cannot fully dissociate, and the number of mobile ions decreases. At the same time, internal moisture cannot be exchanged with the outside through the pores, causing the ion concentration gradient to gradually reach equilibrium and the potential difference to weaken.

[0058] The long-term output voltage of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 8, and 9 was tested at 50% RH. Figure 6 As shown, it can be seen that Embodiment 1, with a higher number of turns, has a higher output voltage.

[0059] The long-term output voltage of the multi-layer spiral structure moisture-generating yarns prepared in Examples 1, 10, and 11 was tested at 50% RH. Figure 7As shown, Example 1 exhibits the highest output voltage because at a pull-out speed of 2 rpm, the sample's weave is very tight, resulting in tiny pores in the carbon fiber woven device, making it difficult for external water molecules to penetrate into the device. Limited by the number of water molecules participating in directional ion migration, the ion migration efficiency inside the device is low, ultimately resulting in a low output voltage. At a pull-out speed of 4 rpm, the pore size and number of the carbon fiber woven structure reach a suitable range: the pore size and number ensure sufficient water molecules can penetrate into the fiber network and device interior, providing a sufficient medium for directional ion migration, while maintaining good interfacial contact area between fibers, ensuring charge separation and transport efficiency. Therefore, the device can achieve a better output voltage at this speed. At a pull-out speed of 6 rpm, the pores in the carbon fiber woven device are larger, reducing the interfacial contact area between fibers, weakening charge separation and transport efficiency, and consequently reducing the potential difference inside the device, resulting in a lower output voltage.

[0060] The long-term output voltage and current of the multi-layer spiral structure moisture-generating yarn prepared in Example 1 were tested at 25°C and 50%RH. Figure 8 As shown in the figure, it can be seen that it has good long-term stability.

[0061] The multi-layer spiral structure moisture-generating yarn prepared in Example 1 was also applied in a real environment for 24 hours. The schematic diagram of the actual application environment and the output voltage change curve during this period are shown below. Figure 9 As shown, it has the effect of sustainable power generation in all weather conditions and has the potential for practical application.

[0062] In summary, this invention designs a multi-layered spiral structure moisture-generating yarn, which, from the inside out, comprises a spiral core yarn, an inner electrode layer, a covering yarn layer, and an outer electrode layer. The presence of the outer electrode layer effectively resists the erosion of environmental factors such as humidity and complex media, extending the service life of the moisture-generating yarn. Simultaneously, it is lightweight, flexible, and possesses excellent breathability and moisture permeability, making it suitable for the knitting and weaving integration needs of smart textiles. Both the core yarn and the covering yarn layer contain hygroscopic salts and nanofiber membranes. When the external humidity is high, the covering yarn layer absorbs moisture, creating a humidity gradient that generates voltage and current. Simultaneously, the core yarn stores water molecules; when the external humidity is low, the stored water molecules diffuse outwards, forming a humidity gradient that generates current and voltage. This design is adaptable to complex temperature and humidity fluctuations throughout the day, enabling sustainable power generation in all weather conditions.

[0063] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 multi-layer spiral structure moisture-generating yarn, characterized in that, From the inside out, it consists of a spiral core yarn, an inner electrode layer, a covering yarn layer, and an outer electrode layer; Both the core yarn and the covering yarn layer contain hygroscopic salts and nanofiber membranes; The covering yarn layer is used to cover the core yarn with the inner electrode layer, so that the core yarn and the inner electrode layer do not come into contact with the outer electrode layer.

2. The multi-layer spiral structure moisture-generating yarn according to claim 1, characterized in that, The inner electrode layer is a metal wire wound around the outer surface of the core yarn.

3. The multi-layer spiral structure moisture-generating yarn according to claim 2, characterized in that, The winding density of the metal wire is 2-10 turns / cm.

4. The multi-layer spiral structure moisture-generating yarn according to claim 1, characterized in that, The outer electrode layer is made of woven carbon fiber.

5. A method for preparing a multi-layered spiral structure moisture-generating yarn, characterized in that, include, Nonwoven fabric is soaked in a hygroscopic salt solution to obtain strip-shaped first and second nonwoven fabrics, wherein the length of the second nonwoven fabric is greater than that of the first nonwoven fabric. Electrospinning is performed on the upper and lower sides of the first and second nonwoven fabrics to form nanofiber membranes, thereby obtaining the core yarn precursor and the covering yarn layer, respectively. The core yarn precursor is processed into a core yarn with a spiral structure, an inner electrode layer is prepared on the surface of the core yarn, and then the core yarn with the inner electrode layer is covered with a covering yarn layer. An outer electrode layer is prepared on the surface of the covered yarn layer. The covered yarn layer prevents the core yarn and inner electrode layer from contacting the outer electrode layer, resulting in a multi-layer spiral structure moisture-generating yarn.

6. The method for preparing the multi-layer spiral structure moisture-generating yarn according to claim 5, characterized in that, The mass concentration of the hygroscopic salt solution is 2%-12%.

7. The method for preparing the multi-layer spiral structure moisture-generating yarn according to claim 5, characterized in that, The spinning solution used in the electrospinning is a 5-20 wt% polyacrylonitrile solution.

8. The method for preparing the multi-layer spiral structure moisture-generating yarn according to claim 5, characterized in that, The external electrode is prepared by braiding, and the pulling speed during braiding is 2-6 rpm.

9. The method for preparing the multi-layer spiral structure moisture-generating yarn according to claim 5, characterized in that, The nonwoven fabric undergoes an oxidation treatment before use.

10. A self-powered energy source, characterized in that, Moisture-generating yarn with a multi-layer spiral structure as described in any one of claims 1-4.

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