An electrostatic spinning friction nanometer generator with special-shaped structure and a preparation method thereof

Abstract

The application discloses a heteromorphic structure electrostatic spinning friction nanometer generator and a preparation method thereof in the technical field of nanometer power generation, and aims to solve the problem of poor electric output performance of the electrostatic spinning friction nanometer generator in the prior art, wherein the two friction layer materials of the triboelectric nanometer generator are both composed of electrostatic spinning nanofibers, the positive friction layer is a nanofiber film with antibacterial polylactic acid / chitosan / aloe vera porous structure, and the negative friction layer is a nanofiber film with polyurethane / carbon black string-bead structure. The nanofibers with the porous structure and the string-bead structure can effectively increase the contact area of the friction layer, and the addition of a certain amount of carbon black in the negative friction layer can effectively improve the triboelectric output performance.

Description

Technical Field

[0001] This invention relates to an electrospinning triboelectric nanogenerator with an irregular structure and its preparation method, belonging to the field of nano-power generation technology. Background Technology

[0002] Wearable electronic devices offer advantages such as being able to be integrated into clothing or worn as accessories without implantation. They not only functionally replace traditional large medical electronic devices, reducing the need for medical professionals and improving quality of life, but also, wearable sensors typically have high power consumption, requiring a stable power source to operate. Traditional batteries require frequent charging, and their inherent rigidity also affects the flexibility and lightweight design of wearable devices.

[0003] Triboelectric nanogenerators (TENGs) can effectively harvest mechanical energy from human movement, wind, and water, and convert it into electrical energy, which can then be integrated into flexible wearable electronic products to address the battery dependence of wearable devices.

[0004] Currently, there are two main approaches to improve the output performance of triboelectric nanogenerators: one is to increase the surface charge by selecting the best friction material or introducing electrets, and the other is to increase the roughness of the friction layer to increase its specific surface area during contact.

[0005] Therefore, nanofiber membranes (NFMs) have the characteristics of high specific surface area, aspect ratio, porosity and abundant contact sites. They provide a larger contact area, which can not only improve the electrical output performance and air permeability of TENG, but also improve sensitivity and response speed due to the unique structure of NFMs, which are all crucial for sensors. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electrospun triboelectric nanogenerator with an irregular structure and its preparation method, thereby improving the electrical output performance of the nanogenerator by improving the dielectric properties of the nanofibers.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing an irregularly shaped electrospun triboelectric nanogenerator, comprising the following steps:

[0009] Carbon black was added to a mixed solvent of N,N-dimethylformamide / acetone, and the mixture was sonicated to obtain a CB-N,N-dimethylformamide / acetone solution; polyurethane was added to the CB-N,N-dimethylformamide / acetone solution and stirred to obtain a polyurethane / carbon black spinning solution.

[0010] Electrospinning of a polyurethane / carbon black spinning solution yields a polyurethane / carbon black beaded nanofiber membrane, which serves as the negative electrode friction layer for an electrospun triboelectric nanogenerator.

[0011] Prepare the positive electrode friction layer of an electrospun triboelectric nanogenerator.

[0012] An electrospinning triboelectric nanogenerator was obtained by assembling the negative electrode friction layer and the positive electrode friction layer.

[0013] Furthermore, the mass percentage of carbon black ranges from 0 to 5 wt%, and the mass percentage of polyurethane ranges from 10 to 20 wt%.

[0014] Furthermore, stirring was carried out at room temperature for 4–6 hours.

[0015] Furthermore, the parameters for electrospinning are set as follows: spinning voltage 45-55kV, and roller receiving distance 18cm.

[0016] Furthermore, the contact area of ​​the negative electrode friction layer ranges from 1 to 9 cm². 2 The thickness of the negative electrode friction layer ranges from 0.05 to 0.40 mm.

[0017] Furthermore, the positive electrode tribological layer of the triboelectric nanogenerator is prepared, including:

[0018] Weigh out polylactic acid, chitosan and aloe vera and dissolve them in a mixed solvent of chloroform / N,N-dimethylformamide to obtain a polylactic acid / chitosan / aloe vera spinning solution;

[0019] Electrospinning of a polylactic acid / chitosan / aloe vera spinning solution yields a porous polylactic acid / chitosan / aloe vera nanofiber membrane, which serves as the positive electrode friction layer for an electrospun triboelectric nanogenerator.

[0020] Furthermore, the negative electrode friction layer and the positive electrode friction layer are assembled to obtain an electrospinning triboelectric nanogenerator, including:

[0021] After cutting the nanofiber membrane, conductive fabric is pasted onto its surface to obtain positive electrode material and negative electrode material;

[0022] The positive and negative electrode materials are pasted onto both sides of an arch shape made of folded paper and then mounted on a linear motor.

[0023] Furthermore, the conductive fabric is a conductive fabric with a nickel-copper coating, which serves as the electrode of the electrospun triboelectric nanogenerator.

[0024] Secondly, the present invention provides an irregularly shaped electrospinning triboelectric nanogenerator, which is prepared by any of the preparation methods described above.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0026] This invention utilizes biocompatible materials to fabricate a fully electrospun triboelectric nanogenerator, which can be used in the fabrication of self-powered wearable sensors. Both friction layers of the nanogenerator are composed of electrospun nanofibers. The positive friction layer is a porous nanofiber membrane with an antibacterial polylactic acid / chitosan / aloe vera extract structure, while the negative friction layer is a polyurethane / carbon black beaded nanofiber membrane. Both the porous and beaded nanofiber structures effectively increase the contact area of ​​the friction layers, and the added carbon black content in the negative friction layer effectively enhances the triboelectric output performance. Attached Figure Description

[0027] Figure 1 This is a schematic SEM image of nanofiber membranes obtained by electrospinning TPU spinning solutions of different mass percentages under different spinning voltages in an embodiment of the present invention.

[0028] Figure 2 The images shown are SEM images, water contact angle images, and color comparison diagrams of TPU / CB BNFMs composed of different mass percentages of CB in embodiments of the present invention, wherein (a) is 0 wt% CB; (b) is 1 wt% CB; (c) is 2 wt% CB; (d) is 3 wt% CB; (e) is 4 wt% CB; and (f) is 5 wt% CB.

[0029] Figure 3 This is a schematic diagram illustrating the basic working mechanism of the TENG device in this embodiment of the invention;

[0030] Figure 4 This is a schematic diagram of the electrical output characteristics of TENG in an embodiment of the present invention, wherein (a) is the output voltage of TPU / CBBNFMs with different CB contents; (b) is the output voltage of TPU / CB BNFMs with different contact areas; (c) is the output voltage of TPU / CB BNFMs with different friction layer thicknesses; and (d) is the output voltage of TPU / CB BNFMs under different external forces.

[0031] Figure 5 The diagram shows the output power of the TENG connected to different resistors in an embodiment of the present invention. (a) shows the relationship between the output voltage and instantaneous peak power density of the TENG under different external load resistors; (b) shows the output voltage of the TENG under an external load resistor of 20MΩ; and (c) shows the output endurance of the TENG voltage (enlarged views of the initial and final stages).

[0032] Figure 6This is a test schematic diagram of the capacitor charging system using TENG in an embodiment of the present invention, wherein (a) is the equivalent circuit diagram of TENG charging a commercial capacitor and the voltage of TENG charging a commercial capacitor; (b) charging a capacitor (2.2μF) by tapping and patting with a finger; (c) charging a stopwatch with a 10μF capacitor; (d) characteristic output signals of TENG when tapping with a finger, (e) walking, and (f) bending.

[0033] Figure 7 This is a schematic diagram of the electrospinning equipment for nanofiber membranes in an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the structure of the electrostatic triboelectric nanogenerator assembled in an embodiment of the present invention;

[0035] In the diagram: 1. Drum, 2. High-voltage power supply, 3. Liquid storage device, 4. Liquid supply device. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0037] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values ​​close to those 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 herein.

[0038] For the purposes of this specification and the appended claims, unless otherwise stated, all expressions, percentages, or proportions, and other numerical values ​​used in this specification and the appended claims, are to be understood to be modified by the term "about" in all cases. Furthermore, all scopes disclosed herein include their endpoints and can be combined independently.

[0039] Example 1:

[0040] This invention provides a method for preparing an irregularly shaped electrospun triboelectric nanogenerator, comprising the following steps:

[0041] Preparation of the positive electrode triboelectric layer for a triboelectric nanogenerator:

[0042] Weigh out polylactic acid, chitosan and aloe vera and dissolve them in a mixed solvent of chloroform / N,N-dimethylformamide (mass percentage 9:1) to obtain a polylactic acid / chitosan / aloe vera spinning solution;

[0043] The polylactic acid / chitosan / aloe vera spinning solution was electrospun at a spinning voltage of 50kV and a roller receiving distance of 18cm to obtain polylactic acid / chitosan / aloe vera spun porous nanofiber membranes (PCAPNFMs), which are the positive electrode friction layer of the electrospun triboelectric nanogenerator.

[0044] Preparation of the negative electrode friction layer for a triboelectric nanogenerator:

[0045] 1 wt% carbon black was added to a mixed solvent of N,N-dimethylformamide / acetone (mass percentage 7:3), and the mixture was sonicated to obtain a CB-N,N-dimethylformamide / acetone solution; 15 wt% polyurethane was added to the CB-N,N-dimethylformamide / acetone solution, and the mixture was stirred for 4 h to obtain a polyurethane / carbon black spinning solution.

[0046] The polyurethane / carbon black spinning solution was electrospun at a spinning voltage of 50kV and a roller receiving distance of 18cm to obtain a polyurethane / carbon black beaded nanofiber membrane (TPU / CB BNFMs), which is the negative electrode friction layer of the electrospun triboelectric nanogenerator.

[0047] Example 2:

[0048] The difference between this embodiment and Embodiment 1 is that the added carbon black has a mass percentage of 2 wt%.

[0049] Example 3:

[0050] The difference between this embodiment and Embodiment 1 is that the added carbon black has a mass percentage of 3 wt%.

[0051] Example 4:

[0052] The difference between this embodiment and Embodiment 1 is that the added carbon black has a mass percentage of 4 wt%.

[0053] Example 5:

[0054] The difference between this embodiment and Embodiment 1 is that the added carbon black has a mass percentage of 5 wt%.

[0055] Example 6:

[0056] The difference between this embodiment and Embodiment 1 is that no carbon black was added, i.e., the mass percentage of carbon black was 0 wt%.

[0057] Comparative Example 1:

[0058] The difference between this comparative example and Example 1 is that the negative electrode friction layer of the triboelectric nanogenerator is prepared by dissolving polyurethane in a mixed solvent of N,N-dimethylformamide / acetone (mass percentage 7:3) to obtain a 10wt% TPU spinning solution.

[0059] Comparative Example 2:

[0060] The difference between this comparative example and Example 1 is that the negative electrode friction layer of the triboelectric nanogenerator is prepared by dissolving polyurethane in a mixed solvent of N,N-dimethylformamide / acetone (mass percentage 7:3) to obtain a 15wt% TPU spinning solution.

[0061] Comparative Example 3:

[0062] The difference between this comparative example and Example 1 is that the negative electrode friction layer of the triboelectric nanogenerator is prepared by dissolving polyurethane in a mixed solvent of N,N-dimethylformamide / acetone (mass percentage 7:3) to obtain a 20wt% TPU spinning solution.

[0063] Example 7:

[0064] like Figure 7 As shown, this embodiment provides a free surface spinning device, including a liquid storage device, a roller and a high voltage power supply. The liquid storage device is connected to a liquid supply device, and the roller serves as a receiving device. The positive terminal of the high voltage power supply is connected to the liquid storage device, and the negative terminal is connected to the roller. An electric field of a certain intensity is formed between the positive and negative terminals, causing the spinning liquid surface on the surface of the liquid storage device to ripple, similar to forming a Taylor cone shape, and further stretching it into nanofibers.

[0065] The samples from Examples 1-6 and Comparative Examples 1-3 are analyzed below with reference to experiments and accompanying figures.

[0066] The spinning solutions obtained in Comparative Examples 1-3 were electrospun at spinning voltages of 45 kV, 50 kV, and 55 kV, respectively. The resulting nanofiber membranes were then scanned using SEM, and the results are as follows: Figure 1 As shown.

[0067] Figure 1 SEM images of nanofiber membranes with different TPU concentrations show that TPU concentration and applied voltage significantly affect fiber morphology. During spinning, the high-voltage electric field promotes fiber formation. When the TPU concentration is too low, only microsphere structures are formed. However, when the TPU concentration is too high, only fiber structures are formed. Under the same voltage, as the solution viscosity (i.e., increasing TPU concentration) increases, the number of microspheres decreases or even disappears completely.

[0068] The results showed that when the TPU concentration was 10 wt%, numerous microspheres were observed, resulting in extremely fine and easily broken fibers. This is because the lower viscosity leads to lower viscous forces, resulting in unstable jets. The instability of the jets makes the capillaries prone to breakage and microsphere formation. Furthermore, excessive uneven adhesion between beads may affect the stability of beaded nanofiber membranes (BNFMs) in subsequent applications. When the TPU concentration reached 20 wt%, the obtained fibers were free of microspheres, as the increased solution viscosity improved jet stability. When the TPU concentration remained constant, taking 15 wt% TPU as an example, the number of jets generated on the SSFSE surface increased with increasing voltage, while the microsphere size decreased. When the voltage reached 55 kV, due to the excessively high spinning speed, the solvent could not evaporate in time, and the fibers were not sufficiently stretched and aggregated into clusters. Therefore, using 15 wt% TPU and an applied voltage of 50 kV is most suitable for preparing beaded fibers.

[0069] In the electrospinning process, the conductivity and viscosity of the spinning solution have a significant impact on the quality of the obtained nanofibers. The conductivity and viscosity of the spinning solution are related to the composition of the mixed solution, as shown in Table 1 (in Table 1, samples with carbon black mass percentages of 0, 1, 2, 3, 4, and 5 wt% are denoted as CB-0, CB-1, CB-2, CB-3, CB-4, and CB-5, respectively).

[0070] Table 1: Conductivity and viscosity of spinning solutions obtained in Examples 1-5 and Comparative Examples 1-3

[0071]

[0072] Table 1 shows that with increasing TPU concentration, the viscosity of the spinning solution increases significantly, while the conductivity initially increases and then decreases. Furthermore, the addition of different CB contents causes significant changes in the viscosity of the spinning solution, indicating that the addition of CB promotes the interaction between TPU molecular chains. The conductivity of the spinning solution reaches its maximum when the CB content reaches 3 wt%. With further increases in CB content, the solution conductivity decreases slightly, mainly due to the poor dispersion of CB in the spinning solution. Carbon black aggregation leads to a slight decrease in solution conductivity and a significant increase in solution viscosity.

[0073] like Figure 2 (a-f) show SEM images and corresponding water contact angles (WCA) of TPU / CB BNFMs with different CB contents. SEM results indicate that carbon black nanoparticles (CB NPs) are uniformly distributed within and on the surface of the TPU nanofibers. With increasing CB content, CB NPs are gradually exposed on the fiber surface, making the fiber surface rougher and leading to an increase in the water contact angle of the BNFMs. Furthermore, the increase in CB content does not affect the formation of the bead-like structure.

[0074] However, it is worth noting that when too much CB is added to the TPU solution, the conductivity hardly increases due to the high solution viscosity, making the electrospinning process more difficult. This results in fibers that are too thin and prone to breakage. Figure 2 As shown in (f). Figure 2 As shown in (g), the color of BNFMs gradually darkens with the increase of CB content.

[0075] like Figure 8 As shown, an electrospun triboelectric nanogenerator is assembled using a negative electrode friction layer and a positive electrode friction layer. The steps include: cutting the nanofiber membrane and then attaching a conductive fabric with a nickel-copper coating to its surface to obtain a positive electrode material and a negative electrode material; attaching the positive electrode material and the negative electrode material to both sides of an arch shape folded from paper and mounting it on a linear motor to make an electrospun triboelectric nanogenerator (TENG).

[0076] The basic working mechanism of TENG composed of PCA PNFMs and TPU / CB BNFMs under vertical compressive force is as follows: Figure 3 As shown. TENG consists of two friction layers, where PCA PNFMs is the positive friction layer and TPU / CB BNFMs is the negative friction layer. Figure 3 (a)). Polylactic acid (PLA) has a greater electron loss capacity than TPU, therefore for PCA PNFMs, biodegradable chitosan (CS) with protonated amino groups gives it a positive charge and is often used as the positive tribological layer for triboelectric applications.

[0077] As shown in the figure, in the original state ( Figure 3 (a) The two friction layers are separated and remain electrically neutral. When the two friction layers come into contact under the action of an external force, due to the triboelectric effect and electrostatic induction, equal and opposite charges are generated at the contact point. Figure 3 (b)). During the TENG release process ( Figure 3 (c) Electrons flow between the electrodes to achieve energy balance. When fully released ( Figure 3 (d) Due to electrostatic induction, the two electrodes have equal and opposite charges. When TENG is subjected to external force again ( Figure 3 (e) The original electrostatic balance is broken, and electrons move in the opposite direction, causing the friction layer to become charged.

[0078] The carbon black content not only affects the morphology of NFMs but also significantly influences their charge storage capacity. To evaluate the electrooutput performance of TPU / CB BNFMs, a compression cycle system was used to repeatedly compress and recover TENGs. The effects of 10 N force and 1 Hz frequency on TPU / CB BNFMs with different CB contents at a thickness of 0.1 mm were investigated (effective contact area of ​​TENG: 2 × 2 cm²). 2 The electrical output performance of TPU / CB BNFMs was used to determine the optimal output performance.

[0079] like Figure 4 As shown in (a), with the increase of CB content, the voltage output first increases and then decreases, indicating that adding too much CB will lead to TPU polymerization and affect the electrical output performance. Combined with... Figure 2 (a-f) As the CB content increases, more and more CB NPs are exposed on the fiber surface, thereby increasing the specific surface area of ​​NFMs and effectively improving the contact area between friction layers. In addition, with the increase of CB content, the dielectric constant and conductivity of NFMs also increase.

[0080] Referring to Table 2:

[0081] Table 2: Conductivity of TPU / CB BNFMs with different CB qualities

[0082]

[0083]

[0084] Table 2 shows that when the CB content is below 3 wt%, the resistance of TPU / CB BNFMs is too high to be measured using a four-probe resistance tester. This is because the CB NPs mainly exist as islands, exhibiting almost insulating characteristics. As the CB content increases, the CB NPs contact each other to form conductive paths. However, when the CB content is greater than 3 wt%, the output performance decreases because the excessively high conductivity of the friction material is not conducive to charge storage.

[0085] Therefore, it can be concluded that an appropriate CB content can effectively improve the output performance of TENG, and the electrical output performance of TENG is best when the CB mass is 3wt%.

[0086] According to the capacitance formula, the overall capacitance of a TENG is closely related to the contact area and thickness of the friction layer. The smaller the friction layer thickness and the larger the contact area, the larger the capacitance of the TENG and the higher the output. Figure 4 (b) shows that at a frequency of 0.5 Hz and an applied force of 3 N, the output voltage of the TENG increases with increasing contact area. Subsequently, the effect of the thickness of the TPU / CB BNFMs on the electrical output performance was investigated. Figure 4 (c) It can be seen that the output first increases and then decreases with the increase of TPU / CB BNFMs thickness. This may be because the thinner friction layer itself carries less charge, resulting in a lower TENG output. The output current is the highest when the friction layer thickness is 0.13mm. Therefore, a contact area of ​​2×2cm is selected. 2 A thickness of 0.13 mm was chosen as the optimal parameter for subsequent research.

[0087] To evaluate the effect of external force on the TENG output voltage, the external force was gradually increased from 1N to 15N at a frequency of 1Hz. Figure 4 (d) It can be seen that the output voltage gradually increases with the increase of force. The increase of external force means that the contact area between the two friction layers becomes larger. In addition, the output voltage is proportional to the external force, which indicates that the fabricated TENG can be used to identify various forces and has the potential to be used as a force sensor.

[0088] Furthermore, resistors of varying resistances are connected to the TENG, and the output power of the TENG is evaluated by measuring the voltage across the resistors. The power density of the TENG can be calculated as follows: Where V p The output peak voltage is given by A, the contact area is given by R, and the load resistance is given by R. The equivalent circuit connection is shown below. Figure 5 As shown in (a), when a force of 10N is applied to the TENG at 1Hz, the voltage across the resistor increases as the external load resistance increases from 750kΩ to 1GΩ. The power density first increases and then decreases. The TENG reaches its maximum instantaneous output power when matched with an external load resistance of 20MΩ, with a peak voltage of 9.91V. Figure 5 (b)).

[0089] Durability is one of the factors that determines the lifespan of electronic products. To confirm its stability and durability, the output voltage performance of the TENG was measured after approximately 7200 seconds of continuous operation at a force of 3N and a frequency of 1Hz. Figure 5 (c) The results show that the TENG's output performance is stable, with no significant decrease during long-term operation, thus demonstrating its excellent durability. Illustrations of the initial and final stages also show the repeatability and stability of the voltage signal. The results indicate that the TENG with TPU / CB BNFMs as the negative electrode tribological layer exhibits good stability and durability, and has potential for practical applications.

[0090] To demonstrate the electrical output capability of the TENG in a practical application, the TENG is connected to a full-bridge rectifier circuit, which can rectify the generated AC output into DC output, thereby enabling the TENG to continuously charge capacitors.

[0091] Figure 6 (a) shows the equivalent circuit diagram of the TENG and the charging curves of commercial capacitors (2.2μF, 6.8μF, 10μF, 22μF, and 33μF) with different capacitances under a pressure of 3Hz and 3N applied within 200s by the TENG. The charging rate gradually decreases as the capacitance increases. A 2.2μF capacitor can be charged to 2.91V within 200 seconds, and even a 33μF capacitor can be charged to 0.44V.

[0092] In addition, pressure was applied to the TENG using a combination of continuous tapping with fingers and clapping, and the resulting electrical energy was stored in a commercial capacitor (2.2 μF). Figure 6 (b)). The results show that the potential of the capacitor can reach 3.27V within 200s. Figure 6 (c) shows the charge-discharge curve of the 10μF capacitor driven by the TENG. By rapidly tapping the TENG with a finger, the capacitor potential reaches 2.01V within 420 seconds. The electrical energy stored in the capacitor can be used to power a battery-free stopwatch. Therefore, the electrical energy stored in the capacitor can power micro-electronic products without a battery.

[0093] Based on the flexibility of electrospun TENGs, their potential applications were further investigated. First, the TENG was placed on a table and tapped lightly with a finger a series of different numbers of times. (Example:...) Figure 6 As shown in (d), tapping the TENG 1, 2, 3, 4, and 5 times consecutively will produce different responses. Then, the TENG is connected to the sole of the shoe to detect walking motion, as shown... Figure 6 As shown in (e). During the walking process, a series of continuous and stable signals can be output, with a voltage output of up to 30V. Furthermore, the TENG undergoes periodic bending and recovery, from... Figure 6 (f) shows that the output is a continuous, regular signal. Therefore, TENG can be used to recognize various human movements.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an irregularly shaped electrospun triboelectric nanogenerator, characterized in that, Includes the following steps: Carbon black was added to a mixed solvent of N,N-dimethylformamide / acetone, and the mixture was sonicated to obtain a CB-N,N-dimethylformamide / acetone solution; polyurethane was added to the CB-N,N-dimethylformamide / acetone solution and stirred to obtain a polyurethane / carbon black spinning solution. Electrospinning of polyurethane / carbon black spinning solution yields a polyurethane / carbon black beaded nanofiber membrane, which serves as the negative electrode friction layer for an electrospun triboelectric nanogenerator. The preparation of the positive electrode tribological layer of the electrospun triboelectric nanogenerator includes: weighing polylactic acid, chitosan and aloe vera and dissolving them in a mixed solvent of chloroform / N,N-dimethylformamide to obtain a polylactic acid / chitosan / aloe vera spinning solution. Electrospinning of polylactic acid / chitosan / aloe vera solution yields a porous polylactic acid / chitosan / aloe vera nanofiber membrane, which serves as the positive electrode friction layer for an electrospun triboelectric nanogenerator. An electrospinning triboelectric nanogenerator was obtained by assembling the negative electrode friction layer and the positive electrode friction layer.

2. The method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to claim 1, characterized in that, The mass percentage of carbon black ranges from 0 to 5 wt%, and the mass percentage of polyurethane ranges from 10 to 20 wt%.

3. The method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to claim 1, characterized in that, Stirring is carried out at room temperature for 4 to 6 hours.

4. The method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to claim 1, characterized in that, The electrospinning parameters are set as follows: spinning voltage 45~55kV, and roller receiving distance 18cm.

5. The method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to claim 1, characterized in that, The contact area of ​​the negative electrode friction layer ranges from 1 to 9 cm². 2 The thickness of the negative electrode friction layer ranges from 0.05 to 0.40 mm.

6. The method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to claim 1, characterized in that, An electrospun triboelectric nanogenerator is obtained by assembling a negative electrode friction layer and a positive electrode friction layer, including: After cutting the nanofiber membrane, conductive fabric is pasted onto its surface to obtain positive electrode material and negative electrode material; The positive and negative electrode materials are pasted onto both sides of an arch shape made of folded paper and then mounted on a linear motor.

7. The method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to claim 6, characterized in that, The conductive fabric is a conductive fabric with a nickel-copper coating, which serves as the electrode of the electrospun triboelectric nanogenerator.

8. An electrospinning triboelectric nanogenerator with an irregular structure, characterized in that, It is prepared by the method for preparing the irregularly shaped electrospun triboelectric nanogenerator according to any one of claims 1 to 7.

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