Polyaniline / Thiourea / Activated Carbon Fiber Integrated Material and Its Preparation Method and Energy Storage Application

Abstract

The present invention discloses a polyaniline / thiourea / activated carbon fiber integrated material, its preparation method and energy storage application. The present invention uses activated carbon fiber as the matrix material, introduces thiourea molecules by grafting synthesis method, and introduces polyaniline by electrochemical polymerization method to synthesize the polyaniline / thiourea / activated carbon fiber integrated material. By introducing thiourea molecules, the activated carbon fiber is connected by amide covalent bond and the polyaniline is connected by hydrogen bond to enhance the interfacial interaction, reduce the transfer resistance between interfaces, enhance the electrochemical performance, significantly improve the electrochemical activity and cycle stability in the integrated structure. This material can be applied to the electrodes of flexible and woven wearable supercapacitors to construct energy storage devices and realize electrochemical energy storage applications.

Description

Technical Field

[0001] The present invention belongs to the field of new materials and new energy, and particularly relates to a polyaniline / thiourea / activated carbon fiber integrated material, a preparation method thereof, and an energy storage application. Background Art

[0002] The exploitation and use of traditional energy resources such as coal, oil, and natural gas have led to resource depletion. These traditional energies are highly polluting and have led to the rise of greenhouse gases and temperature. It is crucial to solve the environmental problems brought by these highly polluting energies.

[0003] A supercapacitor, also known as an electrochemical capacitor, is a type of energy storage device that has a relatively large energy density compared to a conventional capacitor and a high power density compared to a battery. A supercapacitor exhibits as high a power density as a conventional capacitor and an energy density comparable to that of a battery, filling the gap between a battery and a traditional capacitor in terms of energy density and power density.

[0004] To meet the requirements of high-performance supercapacitors, many advanced materials, including carbon, polymers, and metal oxides, have been widely studied. Among them, carbon fiber is often used in carbon-based supercapacitors due to its low weight and high conductivity. However, during the energy storage process, electrons can only be transported at the interface between the carbon fiber and the electrolyte. Therefore, a great deal of effort has been spent on finding an effective solution to increase the active sites of the carbon fiber. Researchers have increased the active sites on the surface of the carbon fiber through methods such as physical and chemical activation. Polyaniline has become a promising electrode material due to its low cost, excellent capacitance, and good conductivity. It should be noted that the volume expansion and contraction will reduce the stability of the polyaniline electrode material during the energy storage process, and there is also a problem of low bonding strength between the polyaniline and the substrate. Therefore, it is urgent to find an effective method to solve the existing problems. Summary of the Invention

[0005] Object of the Invention: Aiming at the problems existing in the prior art, the present invention provides a polyaniline / thiourea / activated carbon fiber integrated material. The material of the present invention has both high energy density and power density and charge-discharge cycle stability, and can effectively solve the phenomenon of irreversible attenuation of capacitance caused by excessive volume expansion / contraction during the process of electrolyte ion insertion / extraction of the polyaniline electrode material.

[0006] The present invention also provides a preparation method and an application of the polyaniline / thiourea / activated carbon fiber integrated material.

[0007] Technical solution: To achieve the above-mentioned invention objective, a polyaniline / thiourea / activated carbon fiber integrated material in the present invention includes activated carbon fiber (1), thiourea (2), and polyaniline (3); the thiourea (2) is respectively connected to the activated carbon fiber (1) and polyaniline (2) through a covalent bond (A) and a hydrogen bond (B) to form an integrated structure.

[0008] Preferably, the polyaniline / thiourea / activated carbon fiber integrated material includes an activated carbon fiber matrix material, a bridging molecule thiourea, and polyaniline. By introducing the bridging molecule thiourea, the activated carbon fiber is covalently bonded with an amide group and the polyaniline is hydrogen-bonded to form a polyaniline / thiourea / activated carbon fiber integrated material. The polyaniline / thiourea / activated carbon fiber integrated material does not require other current collectors and has the characteristic of self-support. Among them, an amide group covalent bond (A) interface is formed between the activated carbon fiber (1) and the thiourea (2), and a hydrogen bond (B) interface is formed between the polyaniline (3) and the thiourea (2). The double amino functional groups of the thiourea are respectively connected to the activated carbon fiber and the polyaniline through covalent bonds and hydrogen bonds at the same time, and the polyaniline / thiourea / activated carbon fiber forms an integrated structure.

[0009] Among them, one end amino group of the thiourea (2) forms an amide group covalent bond (A) with the carboxyl group of the activated carbon fiber (1), and the other end amino group of the thiourea (2) forms a hydrogen bond (B) with the imino group of the polyaniline (3). One end of the thiourea (2) molecule is connected to the activated carbon fiber (1), and the other end of the thiourea (2) molecule is connected to the polyaniline (3), and the polyaniline / thiourea / activated carbon fiber forms a bridge structure.

[0010] Preferably, the polyaniline / thiourea / activated carbon fiber integrated material is composed of an activated carbon fiber matrix material, a bridging molecule thiourea, and polyaniline. The bridging molecule thiourea is covalently bonded to the activated carbon fiber with an amide group and hydrogen-bonded to the polyaniline. The surface of the activated carbon fiber substrate is rough and maintains a longitudinally arranged structure. The relatively rough thiourea / activated carbon fiber can provide more active sites for the deposition of polyaniline. The carboxyl group of the activated carbon fiber forms an amide group covalent bond with the amino group of the thiourea, and the imino group of the polyaniline and the amino group of the thiourea form a hydrogen bond. One end of the thiourea molecule is connected to the activated carbon fiber, and the other end of the thiourea molecule is connected to the polyaniline, and the polyaniline / thiourea / activated carbon fiber forms a bridge structure. This makes the connection between the polyaniline and the activated carbon fiber closer, reduces the interfacial resistance, improves the charge transfer, thereby improving the specific capacitance of the material, and forms a material with high conductivity and high structural stability. The above-mentioned bridge structure characteristics solve the phenomenon that the volume of polyaniline continuously expands and contracts during the charge and discharge process, resulting in a decrease in structural stability, improve its charge and discharge cycle stability, solve the problem that polyaniline falls off from the surface of the activated carbon fiber during the charge and discharge process, and further improve the specific capacitance problem. A high-conductivity and high-structural-stability electrode material is formed.

[0011] Among them, the surface of the activated carbon fiber (1) has oxygen-containing functional groups. The activated carbon fiber (1) maintains the structural characteristics of a vertically arranged and tightly connected fiber bundle, and the polyaniline (3) maintains the structural characteristics of a nano-column crosslinked structure.

[0012] Among them, the molecular model of the activated carbon fiber includes epoxy groups, hydroxyl groups, and carboxyl functional groups. The epoxy groups and hydroxyl groups are distributed on the six-membered fused ring of the graphite carbon plane, and the carboxyl groups are distributed at the edges of the six-membered fused ring of the graphite carbon plane; the molecular model of the polyaniline is a dimer aniline molecule; the molecular model of the thiourea is that one end amino group of the thiourea is covalently bonded to the activated carbon fiber molecule through an amide group, and the other end amino group of the thiourea is hydrogen-bonded to the polyaniline molecule to construct a three-component molecular model of the polyaniline / thiourea / activated carbon fiber integrated material.

[0013] Among them, the polyaniline / thiourea / activated carbon fiber integrated material is subjected to simulation optimization calculations to determine the molecular structure model. Based on the density functional theory calculation of the first principle, the optimized three-component molecular structure is obtained, and the intermolecular distance is obtained. The distance between the imino group of the polyaniline and the amino group of the thiourea is There is a hydrogen bond interface interaction between the polyaniline and the thiourea; an amide group covalent bond is formed between the carboxyl group of the activated carbon fiber and the amino group of the thiourea, and the C-N bond length is There is an amide group covalent bond interface interaction between the activated carbon fiber and the thiourea; the electrostatic potential distribution is obtained. There is an overlap in the electrostatic potential between the polyaniline and the thiourea, and there is a hydrogen bond interface interaction between the polyaniline and the thiourea; the charge population distribution is obtained. The charge value of the imino nitrogen atom of the polyaniline decreases from -0.597 to -0.638, and the hydrogen atom increases from 0.338 to 0.429. The charge value of the amino nitrogen atom of the thiourea decreases from -0.705 to -0.822. There is a hydrogen bond interface interaction between the thiourea and the polyaniline; the charge value of the carboxyl oxygen atom of the activated carbon fiber increases from -0.560 to -0.404, and the carbon atom decreases from 0.660 to 0.415. The charge value of the amino nitrogen atom of the thiourea increases from -0.763 to -0.596, and the hydrogen atom increases from 0.374 to 0.384. There is an amide group covalent bond interaction between the polyaniline and the thiourea.

[0014] The preparation method of the polyaniline / thiourea / activated carbon fiber integrated material of the present invention includes the following steps:

[0015] (1) Using the hydrothermal activation method and the heat treatment activation method, activated carbon fiber is prepared with carbon fiber as the precursor.

[0016] (2) Using the grafting synthesis method, thiourea is added with the activated carbon fiber as the substrate to prepare the thiourea / activated carbon fiber integrated material.

[0017] (3) An electrochemical polymerization method is adopted. Using a thiourea / activated carbon fiber integrated material as the substrate, aniline monomer is added to prepare a polyaniline / thiourea / activated carbon fiber integrated material.

[0018] Among them, for the hydrothermal activation method and heat treatment activation method in step (1): First, the carbon fiber is pretreated by ultrasonic treatment in an absolute ethanol solution for 1 - 2 hours. Then, using a nitric acid solution with a mass fraction of 60% - 65% as the reaction solution, the carbon fiber is subjected to hydrothermal activation treatment at a temperature of 60 - 90 °C for 12 - 16 hours. The obtained sample is washed and dried. Then, heat treatment activation treatment is carried out under a nitrogen atmosphere at a reaction temperature of 500 - 600 °C for 2 - 4 h to obtain activated carbon fiber;

[0019] Among them, for the grafting synthesis method in step (2): Prepare a thiourea solution with a concentration of 0.20 - 0.25 M. Immerse the activated carbon fiber in the thiourea solution and react at a temperature of 80 - 100 °C for 3 - 5 hours. After cooling to room temperature, wash and dry to obtain a thiourea / activated carbon fiber integrated material.

[0020] Among them, for the electrochemical polymerization method in step (3): Construct a three - electrode reaction system. Prepare an aqueous solution containing 1 M sulfuric acid and 0.1 - 0.3 M aniline as the reaction electrolyte solution. Use the thiourea / activated carbon fiber integrated material, a platinum sheet, and a saturated calomel electrode as the working electrode, the counter electrode, and the reference electrode respectively. Adopt cyclic voltammetry with a potential window of - 0.2 V to 0.8 V and a scanning rate of 5 - 10 mV s -1 , and the scanning time is 20 - 25 minutes. After the reaction, wash the working electrode to neutrality and dry it to obtain a polyaniline / thiourea / activated carbon fiber integrated material.

[0021] The application of the polyaniline / thiourea / activated carbon fiber integrated material described in the present invention in constructing a flexible and woven wearable supercapacitor for realizing flexible energy storage.

[0022] Among them, the specific process of the application is: using the polyaniline / thiourea / activated carbon fiber integrated material to form a self-supporting structure electrode, and serving as the positive electrode and negative electrode respectively; the gel polymer electrolyte is a three-component composite of sulfuric acid, polyvinyl alcohol and water; the diaphragm is a polypropylene non-woven fabric; the packaging film is an elastic silicone rubber; the gel polymer electrolyte is coated on the surface of the positive electrode and the negative electrode respectively, the diaphragm covers the positive electrode or the negative electrode, the positive electrode, the negative electrode and the diaphragm are stacked layer by layer to form a coating structure, and are entangled with each other to form a spiral shape, and the packaging film is used to encapsulate the positive electrode, the negative electrode, the diaphragm and the gel polymer electrolyte to construct a flexible linear supercapacitor; the prepared flexible linear supercapacitor is fixed on the flexible fabric of clothes and backpacks by a weaving method to construct a flexible weavable wearable supercapacitor to achieve flexible energy storage; the preparation method of the gel polymer electrolyte: weigh 1g of polyvinyl alcohol into a flask, add 5-20mL of distilled water, and continue stirring at a constant temperature of 80-90℃ until the polyvinyl alcohol is completely dissolved, and then 5-10mL 1M sulfuric acid is added dropwise into the flask, stirred thoroughly to form a homogeneous state, and then stirred for 2-3 hours to evaporate excess water, thereby finally preparing a gel polymer electrolyte; the gel polymer gel electrolyte has an optimized component ratio, with the mass ratio of sulfuric acid, polyvinyl alcohol and water being 1.5:1:10.

[0023] Furthermore, the flexible weavable wearable supercapacitor has a rated operating voltage of 1.6V and can stably charge and discharge in different states such as twisted, bent, and folded. The specific capacitance in the twisted state is 25.4F g -1 The specific capacitance in the bent state is 31.6F g-1, and in the folded state is 25.3F g-1; the capacitance retention rate after 2000 charge and discharge cycles is 90.1%.

[0024] The polyaniline / thiourea / activated carbon fiber integrated material prepared by the present invention has carbon fibers with excellent mechanical properties and high inherent conductivity, which is the basis for its wide use as reinforcing materials in structural composite materials and its role as conductive supports in electrochemical energy storage systems. A key component of the performance of carbon fibers in composite materials in electrochemical energy storage is the interface, which shows the interaction between the hard carbon fibers and the active materials. These nanoscale interface regions affect the electrochemical performance due to poor adhesion between the fiber matrix and the active material. The polyaniline / thiourea / activated carbon fiber integrated material described in the present invention has both the high conductivity and specific surface area of activated carbon fibers and the high electrochemical activity and conductivity of polyaniline. The introduction of thiourea bridge molecules to covalently link polyaniline and activated carbon fibers with hydrogen bonds and amide groups improves the structural stability of the material. It can be used as a supercapacitor electrode material for electrochemical high-efficiency energy storage.

[0025] The polyaniline / thiourea / activated carbon fiber integrated material of the present invention forms a binder-free supercapacitor electrode material through the bridging molecule thiourea to connect polyaniline by hydrogen bonds and activated carbon fiber by amide group covalent bonds, realizing electrochemical energy storage. The presence of the activated carbon fiber substrate provides favorable support for polyaniline, and the introduction of thiourea strengthens the structure of polyaniline nanorods, slowing down the degree of structural collapse of the electrode material during charge and discharge processes, enhancing the cycle stability of the electrode material. In addition, the introduction of thiourea enhances the interfacial interaction between polyaniline and activated carbon fiber, reduces the interfacial resistance, improves the charge transfer, thereby increasing the specific capacitance of the material and achieving the effect of enhanced energy storage.

[0026] The present invention designs and synthesizes a polyaniline / thiourea / activated carbon fiber integrated material with a bridging structure. By introducing the bridging molecule thiourea to bond the carbon fiber matrix material with good high conductivity and stability to polyaniline through hydrogen bonds and amide group covalent bonds, its capacitance performance is improved, making the polyaniline / thiourea / activated carbon fiber integrated material have good electrochemical performance. The feature of the present invention is that by introducing the bridging molecule thiourea to form a bridging structure by connecting activated carbon fiber with amide group covalent bonds and connecting polyaniline with hydrogen bonds, the interfacial resistance is reduced, the charge transfer is improved, and thus the specific capacitance of the material is increased. At the same time, it solves the problem of irreversible attenuation of capacitance caused by excessive volume expansion / shrinkage of the polyaniline electrode material during the process of electrolyte ion insertion / extraction, and improves its charge-discharge cycle stability performance.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] The polyaniline / thiourea / activated carbon fiber integrated material prepared by the present invention has the characteristics of both high conductivity and high structural stability, can effectively improve the structural stability of the electrode material, and has a high specific capacitance and good cycle stability.

[0029] In the polyaniline / thiourea / activated carbon fiber integrated material prepared by the present invention, the activated carbon fiber has high conductivity and provides a substrate for the active material. After introducing thiourea, more active sites are provided, connecting polyaniline by hydrogen bonds and connecting activated carbon fiber by amide group covalent bonds, reducing the interfacial resistance, improving the charge transfer, thereby increasing the specific capacitance of the material and solving the problem of structural collapse of polyaniline during charge and discharge.

[0030] The preparation process of the present invention is simple and convenient. The prepared material can be applied to flexible and woven wearable supercapacitor electrodes, construct energy storage devices, realize electrochemical energy storage applications, and has very good prospects. Description of the Drawings

[0031] Figure 1Schematic diagram of the structure of the polyaniline / thiourea / activated carbon fiber integrated material, where (1) is the activated carbon fiber, (2) is the thiourea, and (3) is the polyaniline. The activated carbon fiber (1) is connected to the thiourea (2) through an amide bond (A), and the polyaniline (3) and the thiourea (2) are connected through a hydrogen bond (B), synthesizing the polyaniline / thiourea / activated carbon fiber integrated material with a bridge structure; (A) amide bond; (B) hydrogen bond.

[0032] Figure 2 Process flow chart for the preparation of the polyaniline / thiourea / activated carbon fiber integrated material, where (I) is the pure carbon fiber, (II) is the activated carbon fiber, (III) is the thiourea / activated carbon fiber, and (IV) is the polyaniline / thiourea / activated carbon fiber; (I) surface activation method, (II) graft synthesis method, (III) electrochemical polymerization method. The thiourea (b) is covalently bonded to the activated carbon fiber (a) through an amide group and is connected to the polyaniline (c) through a hydrogen bond, forming the polyaniline / thiourea / activated carbon fiber integrated material with a bridge structure.

[0033] Figure 3 Scanning electron microscope images of the polyaniline / thiourea / activated carbon fiber integrated material, the thiourea / activated carbon fiber integrated material, and the activated carbon fiber. Among them, (A) is the scanning electron microscope image of the activated carbon fiber, (B) is the scanning electron microscope image of the thiourea / activated carbon fiber, and (C) and (D) are the scanning electron microscope images of the polyaniline / thiourea / activated carbon fiber integrated material at different magnifications.

[0034] Figure 4 Infrared spectrum diagram of the polyaniline / thiourea / activated carbon fiber integrated material.

[0035] Figure 5 Electrochemical performance test diagrams of the activated carbon fiber, the thiourea / activated carbon fiber, the polyaniline / activated carbon fiber, and the polyaniline / thiourea / activated carbon fiber integrated material: (A) Cyclic voltammogram at a scanning rate of 5 mV s-1, (B) Charge-discharge test curve at a current density of 1.0 Ag -1 when, (C) Specific capacity-current density relationship curves at different current densities of 1.0, 2.0, 3.0, 5.0, 8.0, and 10.0 Ag -1 when, (D) Electrochemical impedance spectroscopy diagram and its equivalent circuit diagram.

[0036] Figure 6 Electrochemical performance test diagram of the polyaniline / thiourea / activated carbon fiber integrated material: (A) Cyclic voltammogram; the a, b, c, d, e, and f marked in the figure represent scanning rates of 1.0, 2.0, 3.0, 5.0, 8.0, and 10 mV s -1Cyclic voltammetry test curves at [specific time]. (B) Charge-discharge test curves. In the figure, a, b, c, d, e, and f marked respectively represent different current densities of 0.5, 1.0, 2.0, 3.0, 5.0, and 10.0 A / g -1 Charge-discharge test curves.

[0037] Figure 7 Are the cyclic charge-discharge curves of activated carbon fiber, thiourea / activated carbon fiber, polyaniline / activated carbon fiber, and polyaniline / thiourea / activated carbon fiber integrated materials.

[0038] Figure 8 Are the theoretical calculations of polyaniline / thiourea / activated carbon fiber integrated materials: (A) Optimized molecular model of thiourea / activated carbon fiber after calculation. (B) Optimized molecular model of polyaniline / thiourea / activated carbon fiber after calculation. (C) Electrostatic potential distribution of polyaniline / thiourea / activated carbon fiber. (D) Charge population distribution of activated carbon fiber, thiourea, and thiourea / activated carbon fiber. (E) Charge population distribution of polyaniline, thiourea / polyaniline, and polyaniline / thiourea / activated carbon fiber.

[0039] Figure 9 Are (A) Schematic process diagram of a flexible and woven wearable supercapacitor, where ① is the electrode material, ② is the electrode material coated with a gel polymer electrolyte, ③ is the electrode material further coated with a separator, ④ is the wound positive electrode material coated with a gel polymer electrolyte and the negative electrode material coated with a gel polymer electrolyte and further coated with a separator, ⑤ is the flexible linear supercapacitor formed by encapsulating with elastic silicone rubber, and ⑥ is the flexible and woven wearable supercapacitor. (Ⅰ) Coating the gel, (Ⅱ) Coating the separator, (Ⅲ) Winding, (Ⅳ) Encapsulating, (Ⅴ) Weaving. (B) Optical images of the flexible linear supercapacitor and the woven wearable supercapacitor. (C) CV curves of the flexible and woven wearable supercapacitor in different states including twisting, bending, and folding at a scanning rate of 50 mV / s -1 At [specific time], (D) Optical images of the flexible and woven wearable supercapacitor in different states including twisting, bending, and folding. (E) Cyclic charge-discharge curves of the flexible and woven wearable supercapacitor. Detailed implementation manners

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] The materials, reagents, etc. used in the embodiments can be obtained from commercial channels without special instructions.

[0042] Carbon fiber: SYT45 3K, Zhongfu Shenying Carbon Fiber Co., Ltd.;

[0043] Thiourea: Analytical pure, Shanghai Lingfeng Chemical Reagent Co., Ltd.;

[0044] Aniline: Analytically pure, Shanghai Macklin Biochemical Co., Ltd.

[0045] Example 1

[0046] The process flow chart for the preparation of the polyaniline / thiourea / activated carbon fiber integrated material of the present invention is shown in detail in Figure 2 . Among them, (i) carbon fiber, (ii) activated carbon fiber, (iii) thiourea / activated carbon fiber, (iv) polyaniline / thiourea / activated carbon fiber; (I) hydrothermal activation method and heat treatment activation method to obtain activated carbon fiber after activation; (II) graft synthesis method to obtain the thiourea / activated carbon fiber integrated material; (III) electrochemical polymerization method to finally obtain the polyaniline / thiourea / activated carbon fiber integrated material. Among them, thiourea (b) is covalently bonded to activated carbon fiber (a) through an amide group and hydrogen-bonded to polyaniline (c) to form a bridge-structured polyaniline / thiourea / activated carbon fiber integrated material.

[0047] The specific preparation steps of the polyaniline / thiourea / activated carbon fiber integrated material are as follows:

[0048] (1) Synthesis of activated carbon fiber material:

[0049] First, 30 mg of carbon fiber was ultrasonically treated (200 W) in 50 mL of anhydrous ethanol solution for 2 hours for pretreatment, and then, using 50 mL of 60% by mass nitric acid solution as the reaction solution, the pretreated carbon fiber was immersed in the reaction solution for hydrothermal activation treatment at a temperature of 90 °C for 12 hours. The obtained sample was washed with deionized water and dried at 60 °C for 12 h. The obtained carbon fiber sample was subjected to heat treatment activation treatment under a nitrogen atmosphere at a reaction temperature of 600 °C, and the heating rate from room temperature to the reaction temperature was 4 °C min -1 , and the time was 4 h to obtain activated carbon fiber.

[0050] (2) Synthesis of thiourea / activated carbon fiber integrated material:

[0051] A thiourea solution with a concentration of 0.22 M was prepared. 10 mg of activated carbon fiber was immersed in 30 mL of the thiourea solution and placed in a reaction kettle for a chemical reaction at a temperature of 90 °C for 4 hours, and then naturally cooled to room temperature, washed with distilled water until neutral, and then dried in an oven at 60 °C for 12 h to obtain the thiourea / activated carbon fiber integrated material.

[0052] (3) Synthesis of polyaniline / thiourea / activated carbon fiber integrated material:

[0053] A three - electrode reaction system was constructed. An aqueous solution containing 1 M sulfuric acid and 0.1 M aniline was prepared as the reaction solution. 12 mg of the thiourea / activated carbon fiber integrated material was immersed in the above - mentioned 50 mL reaction solution. The thiourea / activated carbon fiber integrated material, a platinum sheet, and a saturated calomel electrode were used as the working electrode, the counter electrode, and the reference electrode respectively. Cyclic voltammetry was adopted with a potential window of - 0.2 V to 0.8 V and a scanning rate of 5 mV s -1 , and the scanning time was 20 minutes. The working electrode after the reaction was washed with distilled water until neutral and then dried in an oven at 60 °C for 12 h to obtain the polyaniline / thiourea / activated carbon fiber integrated material.

[0054] The microstructure schematic diagram of the polyaniline / thiourea / activated carbon fiber integrated material prepared in the present invention is as shown in Figure 1 . As shown in Figure 1 , where (1) is the activated carbon fiber, (2) is the thiourea, and (3) is the polyaniline. The activated carbon fiber (1) is connected to the thiourea (2) through an amide bond (A), and the polyaniline (3) and the thiourea (2) are connected through a hydrogen bond (B), synthesizing the bridge - structured polyaniline / thiourea / activated carbon fiber integrated material.

[0055] Example 2

[0056] The morphology and structure of the polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1 were characterized. For details, see Figure 3 , Figure 3 . (A) and (B) are the scanning electron microscope images of the activated carbon fiber (prepared in step (1) of Example 1) and the thiourea / activated carbon fiber (prepared in step (2) of Example 1) respectively; (C) and (D) are the electron microscope images of the polyaniline / thiourea / activated carbon fiber at different magnifications. Figure 3 . As shown in (A) and (B) in , the surface of the activated carbon fiber is rough and maintains a longitudinally arranged structure, and there are many concave patterns on the surface of the thiourea / activated carbon fiber. The thiourea / activated carbon fiber can provide more active sites for the deposition of polyaniline. Figures (C) and (D) show that the polyaniline nanorods are closely attached to the surface of the activated carbon fiber, and the polyaniline maintains the characteristic of the nanorod cross - linked structure, indicating that the polyaniline, the activated carbon fiber, and the thiourea molecules interact closely. There is a dense layer on the surface of the activated carbon fiber, and many small nanoparticles are dispersed on the side walls of the activated carbon fiber. These nanoparticles can serve as the nucleation sites for the growth of polyaniline. In addition, it provides a more favorable environment for electron transfer and essentially promotes the electron transfer between the polyaniline and the activated carbon fiber.

[0057] Example 3

[0058] The infrared spectrum of the polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1 was characterized. For details, see Figure 4 , Figure 4It is the infrared spectrum of the polyaniline / thiourea / activated carbon fiber integrated material. The characteristic peaks at 1097 cm -1 , 1383 cm -1 , 1633 cm -1 and 3450 cm -1 shown in the activated carbon fiber prepared in step (1) of Example 1 represent the C-O stretching vibration of epoxy functional groups, O-H deformation vibration, C=O stretching vibration of -COOH and C=C stretching vibration of benzene rings. In the thiourea / activated carbon fiber prepared in step (2) of Example 1, the N-H stretching vibration occurs at 3100 - 3500 cm-1. The characteristic peak at 1594 cm -1 represents the N-H bending vibration, and the characteristic peak at 1089 cm -1 represents the C-N- stretching vibration. The characteristic peaks at 1427 cm -1 and 1465 cm -1 represent the N=S stretching vibration. Compared with the C=O stretching vibration of the activated carbon fiber, the C=O stretching vibration of the thiourea / activated carbon fiber is at 1616 cm -1 , which is consistent with the position of the amide I band. The bending vibration of N-H is at 1585 cm -1 , which is consistent with the position of the amide II band. It is confirmed that the amino group of thiourea reacts with the carboxyl group on the activated carbon fiber to form an amide bond. The characteristic wave numbers of the polyaniline / thiourea / activated carbon fiber prepared in step (3) of Example 1 are at 1236, 1303 and 1479 cm -1 respectively representing the C-N stretching vibration of the quinone ring, the C-N + stretching vibration of the quinone ring and the C=N stretching vibration of the benzene ring. The peak at 3100 - 3500 cm -1 represents the N-H stretching vibration, indicating the successful synthesis of polyaniline. Compared with the thiourea / activated carbon fiber, the N-H stretching vibration peak at 3476 cm -1 undergoes a red shift to 3450 cm -1 , and the N-H bending vibration peak red shifts to 1552 cm -1 . It is confirmed that in the polyaniline / thiourea / activated carbon fiber, the imino group of polyaniline binds to the amino group of the thiourea / activated carbon fiber through hydrogen bonds. In summary, one end of the thiourea molecule forms an amide bond with the carboxyl group of the activated carbon fiber, and the other end forms a hydrogen bond with the imino group of polyaniline, forming a bridge structure.

[0059] Example 4

[0060] The electrochemical performance of the polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1 was tested. For details, see Figure 5 . As Figure 5As shown in (A), with 10 mg of activated carbon fiber, 12 mg of thiourea / activated carbon fiber, 12 mg of polyaniline / activated carbon fiber integrated material, and 14 mg of polyaniline / thiourea / activated carbon fiber integrated material as the working electrode, a platinum sheet as the counter electrode, and a saturated calomel electrode as the reference electrode, in a 50 mL sulfuric acid electrolyte with a concentration of 1.0 M, the set potential range is -0.2 - 0.6 V, and the scanning rate is 5 mV s -1 . Among them, (a), (b), (c), and (d) are the cyclic voltammograms of activated carbon fiber (prepared in step (1) of Example 1), thiourea / activated carbon fiber (prepared in step (2) of Example 1), polyaniline / activated carbon fiber integrated material (using the method of Example 1, omitting step (2) and directly using activated carbon fiber as the working electrode), and polyaniline / thiourea / activated carbon fiber integrated material, respectively. The maximum response current densities of these four electrode materials are 7.07, 4.21, 0.47, and 0.16 Ag -1 , and the integral area of the closed curve of the polyaniline / thiourea / activated carbon fiber integrated material is significantly larger than that of the polyaniline / activated carbon fiber, thiourea / activated carbon fiber, and activated carbon fiber integrated materials.

[0061] The formula for estimating the specific capacitance of the material based on the cyclic voltammogram is:

[0062] C = Q / (△V×m) = [∫(I×dU)] / (ν×△V×m)

[0063] where Q is the charge quantity, dU represents the differential of the potential U, △V, ν, and I represent the potential window, scanning rate, and response current of the cyclic voltammetry test, respectively, and m is the effective mass of the active substance. The estimated specific capacitance values of the activated carbon fiber, thiourea / activated carbon fiber, polyaniline / activated carbon fiber integrated material, and polyaniline / thiourea / activated carbon fiber integrated material are 33.75 F g -1 , 70 F g -1 , 275 F g -1 and 541.25 F g -1 , and the experimental results show that the polyaniline / thiourea / activated carbon fiber integrated material has a faster ion transport and exchange ability at the same scanning rate, so it exhibits a higher current density and specific capacitance.

[0064] Perform an electrochemical constant current charge-discharge performance test on the polyaniline / thiourea / activated carbon fiber integrated material, as Figure 5(B) shows the galvanostatic charge-discharge curves of activated carbon fiber, thiourea / activated carbon fiber, polyaniline / activated carbon fiber integrated material, and polyaniline / thiourea / activated carbon fiber integrated material, where (a), (b), (c), and (d) are respectively. It can be seen from the figure that the galvanostatic discharge time of the polyaniline / thiourea / activated carbon fiber integrated material is significantly longer than that of the other three electrode materials, indicating that it has a higher specific capacitance. From the figure, the specific capacitances of activated carbon fiber, thiourea / carbon fiber, polyaniline / activated carbon fiber integrated material, and polyaniline / thiourea / activated carbon fiber integrated material are 27.9 F g -1 -1, 48.9 F g -1 -1, 296.3 F g -1 -1, and 563.8 F g -1 -1, respectively. The experimental results are consistent with the cyclic voltammetry test results, also indicating that the introduction of the bridging molecule thiourea increases the conductivity of polyaniline / activated carbon fiber, thereby enabling it to have a higher electrochemical capacitance. Figure 5 (C) shows the specific capacitance performance of activated carbon fiber, thiourea / activated carbon fiber, polyaniline / activated carbon fiber integrated material, and polyaniline / thiourea / activated carbon fiber integrated material at different current densities (1.0 - 10.0 A g -1 -1). When the current density increases from 1.0 to 10.0 A g -1 -1, the specific capacitance of the polyaniline / thiourea / activated carbon fiber integrated material decreases from 563.8 to 420.8 F g -1 -1, and the specific capacitance retention rate is 74.6%. As a comparative experiment, the specific capacitance retention rate of activated carbon fiber is 53.8%. The specific capacitance retention rate of the thiourea / activated carbon fiber integrated material is 55.2%. The specific capacitance retention rate of the polyaniline / activated carbon fiber integrated material is 63.8%. Thus, the polyaniline / thiourea / activated carbon fiber integrated material exhibits higher specific capacitance and rate performance. It shows that the introduction of thiourea makes the connection between polyaniline and activated carbon fiber closer, reduces the interfacial resistance, improves the charge transfer, thereby increasing the specific capacitance of the material and achieving the effect of enhanced energy storage.

[0065] Figure 5 (D) shows the AC impedance spectra of activated carbon fiber, thiourea / activated carbon fiber, polyaniline / activated carbon fiber, and polyaniline / thiourea / activated carbon fiber integrated material in 1.0 M sulfuric acid solution under the condition of a frequency scanning range of 100 KHz - 10 mHz. It can be seen from the figure that the AC impedance spectra of the four electrode materials are linearly distributed in the low-frequency range and semicircularly distributed in the high-frequency range. Through the fitting analysis of the electrochemical AC impedance spectra of the electrode materials, the fitting results of the equivalent circuit diagram elements are shown in Table 1 below.

[0066] Table 1 Fitting data of equivalent circuit diagram elements of materials

[0067] Electrode material <![CDATA[R o (Ω)]]> CPE1 <![CDATA[R ct (Ohm)]]> <![CDATA[W o (Ω)]]> Activated carbon fiber 3.65 1.08 3.78 0.73 Thiourea / activated carbon fiber 3.40 0.95 3.15 0.41 Polyaniline / activated carbon fiber 1.97 0.68 2.04 0.44 Polyaniline / thiourea / activated carbon fiber 0.70 0.88 2.18 0.49

[0068] According to the experimental fitting results and calculation results, it can be seen that during the electrochemical reaction process, compared with activated carbon fibers, thiourea / activated carbon fibers, and polyaniline / activated carbon fiber integrated materials, in the high-frequency region, polyaniline / thiourea / activated carbon fibers obtain the lowest ohmic resistance (R o ) of 0.70 Ω, reflecting its excellent electrical conductivity. However, the Rct of polyaniline / thiourea / activated carbon fibers is relatively large, which may be due to the slow additional redox reaction of polyaniline nanorods. In the low-frequency range, polyaniline / thiourea / activated carbon fibers exhibit higher capacitive characteristics due to their linear slope compared to polyaniline / activated carbon fibers and activated carbon fibers.

[0069] Example 5

[0070] The polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1 was subjected to electrochemical cyclic voltammetry performance testing and electrochemical galvanostatic charge-discharge performance testing, as detailed in Figure 6 .

[0071] As Figure 6 (A) shows, using 14 mg of the polyaniline / thiourea / activated carbon fiber integrated material as the working electrode, a platinum sheet as the counter electrode, and a saturated calomel electrode as the reference electrode, in a 50 mL volume of 1.0 M sulfuric acid electrolyte, the set potential range is -0.2 - 0.6 V, and the scanning rate is 1 - 10 mV s -1 . It can be seen from the figure that when the scanning rate ranges from 1 mV s -1 to 10 mV s -1 , the CV curves with similar shapes indicate that the polyaniline / thiourea / activated carbon fibers have excellent reversibility. In addition, as the scanning rate increases, the potential displacement of the anodic peak and cathodic peak increases, indicating that the pseudocapacitive reaction is gradually affected by the diffusion process. As Figure 6 (B) shows, when the current density ranges from 0.5 Ag -1 to 10.0 Ag -1 , the galvanostatic charge-discharge curves maintain good linear symmetry characteristics, indicating that the electrode material has good electrochemical reversibility and Coulomb efficiency during the galvanostatic charge-discharge process.

[0072] Example 6

[0073] The polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1 was subjected to electrochemical cyclic charge-discharge performance testing, as detailed in Figure 7 .

[0074] Using 10 mg of activated carbon fiber, 12 mg of thiourea / activated carbon fiber, 12 mg of polyaniline / activated carbon fiber integrated material, and 14 mg of polyaniline / thiourea / activated carbon fiber integrated material as the working electrode, a platinum sheet as the counter electrode, and a saturated calomel electrode as the reference electrode, in 50 mL of 1.0 M sulfuric acid electrolyte, with the set potential range of -0.2 V - 0.6 V and a constant current density of 5 A g -1 , perform 2000 cycles of charge and discharge. Figure 7 The following are the charge-discharge curves of activated carbon fiber, thiourea / activated carbon fiber, polyaniline / activated carbon fiber, and polyaniline / thiourea / activated carbon fiber integrated materials. After 2000 cycles, the retention rate of the specific capacitance of activated carbon fiber is 99.2%. Correspondingly, the retention rate of the specific capacitance of the thiourea / activated carbon fiber material is 98.9%, the retention rate of the specific capacitance of the polyaniline / activated carbon fiber material is 81.3%, and the retention rate of the specific capacitance of the polyaniline / thiourea / activated carbon fiber material is 89.1%. The experimental results show that introducing thiourea molecules to covalently bond polyaniline and activated carbon fiber through hydrogen bonds and amide groups can improve the stability of the material and avoid the collapse of the material structure. The polyaniline / thiourea / activated carbon fiber integrated material has excellent cycle stability. The polyaniline nanorods form a bridge structure through the bridging molecule thiourea to solve the problem of the continuous expansion and contraction of the volume of polyaniline during charge and discharge, resulting in a decrease in structural stability, improve its charge-discharge cycle stability, solve the problem of the detachment of polyaniline nanorods from the surface of activated carbon fiber during charge and discharge, and further improve the specific capacity problem. Thus, it not only increases the electrochemical capacitance performance of polyaniline / thiourea / activated carbon fiber but also extends its electrochemical cycle life.

[0075] Example 7

[0076] Perform theoretical simulation calculations on the polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1. For details, see Figure 8 .

[0077] Figure 8 (A) and Figure 8(B) shows the multi-component molecular models of thiourea / activated carbon fiber and polyaniline / thiourea / activated carbon fiber integrated materials. The molecular model of activated carbon fiber includes epoxy, hydroxyl, and carboxyl functional groups. The epoxy and hydroxyl groups are distributed on the six-membered fused ring of the graphite carbon plane, and the carboxyl group is distributed at the edge of the layer. The molecular model of polyaniline is a dimer aniline molecule. The molecular model of thiourea is that one end amino group of thiourea is covalently bonded to the activated carbon fiber through an amide group, and the other end amino group of thiourea is hydrogen-bonded to the polyaniline molecule to construct the multi-component molecular model of polyaniline / thiourea / activated carbon fiber integrated materials. Based on the density functional theory calculation of the first principles, the optimized multi-component molecular model is obtained. In the molecular model of thiourea / activated carbon fiber integrated materials, an amide group covalent bond is formed between the carboxyl group of the activated carbon fiber and the amino group of thiourea, and the C-N bond length is There is an amide group covalent bond interface interaction between the activated carbon fiber and thiourea. In the molecular model of polyaniline / thiourea / activated carbon fiber integrated materials, the distance between the imino group of polyaniline and the amino group of thiourea is There is a hydrogen bond interface interaction between polyaniline and thiourea; Figure 8 (C) shows the electrostatic potential distribution of polyaniline / thiourea / activated carbon fiber. There is an overlap in the electrostatic potential between polyaniline and thiourea, indicating a hydrogen bond interface interaction between polyaniline and thiourea. Figure 8 (D) shows the charge population distributions of activated carbon fiber, thiourea, and thiourea / activated carbon fiber. The charge value of the carboxyl oxygen atom on the activated carbon fiber increases from -0.560 to -0.404, and the carbon atom decreases from 0.660 to 0.415. The charge value of the amino nitrogen atom on thiourea increases from -0.763 to -0.596, and the hydrogen atom increases from 0.374 to 0.384. There is an amide group covalent bond interaction between polyaniline and thiourea. Figure 8 (E) shows the charge population distributions of polyaniline, thiourea / polyaniline, and polyaniline / thiourea / activated carbon fiber. The charge value of the imino nitrogen atom on polyaniline decreases from -0.597 to -0.638, and the hydrogen atom increases from 0.338 to 0.429. The charge value of the amino nitrogen atom of thiourea decreases from -0.705 to -0.822. There is a hydrogen bond interface interaction between thiourea and polyaniline, further demonstrating the excellent properties of the overall material.

[0078] Example 8

[0079] The flowchart of the flexible and woven wearable supercapacitor constructed using the polyaniline / thiourea / activated carbon fiber integrated material prepared in Example 1 and its electrochemical performance are shown in detail in Figure 9 .

[0080] Preparation method of gel polymer electrolyte: Weigh 1 g of polyvinyl alcohol (with a molecular weight of 17,600 - 26,400) and put it into a flask. Add distilled water and continuously stir at a constant temperature of 90 °C until the polyvinyl alcohol is completely dissolved. Then, gradually add 1 M sulfuric acid dropwise into the flask, stir well to form a homogeneous state, and then keep stirring for 2 hours. Evaporate the excess water to finally obtain the gel polymer electrolyte; optimize the component ratio of the gel polymer gel electrolyte, and the mass ratio of sulfuric acid, polyvinyl alcohol, and water is 1.5:1:10.

[0081] Figure 9 (A) shows the process schematic diagram of the woven wearable supercapacitor. The polyaniline / thiourea / activated carbon fiber integrated material forms a self-supporting structure electrode and serves as the positive electrode and the negative electrode respectively; among them, ① is the electrode material (i.e., the polyaniline / thiourea / activated carbon fiber integrated material), ② is the electrode material after coating with the gel polymer electrolyte, ③ is the electrode material after further coating with the separator polypropylene non-woven fabric, ④ is the wound positive electrode material coated with the gel polymer electrolyte and the negative electrode material coated with the gel polymer electrolyte and coated with the separator, ⑤ is the flexible linear supercapacitor formed by encapsulating the elastic silicone rubber, and ⑥ is the flexible woven wearable supercapacitor formed by weaving the linear supercapacitor. (Ⅰ) Coating the gel, (Ⅱ) Coating the separator, (Ⅲ) Winding, (Ⅳ) Encapsulating, (Ⅴ) Weaving. The gel polymer electrolyte is respectively coated on the surfaces of the positive electrode and the negative electrode. The separator is coated on the positive electrode or the negative electrode. The positive electrode, the negative electrode, and the separator are stacked layer by layer to form a coated structure, and are wound around each other to form a spiral shape. The positive electrode, the negative electrode, the separator, and the gel polymer electrolyte are encapsulated with a packaging film to construct a flexible linear supercapacitor. The obtained flexible linear supercapacitor is fixed on the flexible fabrics such as clothes and backpacks by a weaving method to construct a flexible woven wearable supercapacitor.

[0082] Figure 9 (B) shows the optical images of the flexible linear supercapacitor and the flexible woven wearable supercapacitor. Figure 9 (C) shows the CV curves of the flexible woven wearable supercapacitor in different states including twisting, bending, and folding at a scanning rate of 50 mV s -1 When. The rated working voltage of the flexible woven wearable supercapacitor is 1.6 V, and it can stably charge and discharge in different states such as twisting, bending, and folding states. The specific capacitance in the twisting state is 25.4 F g -1 , the specific capacitance in the bending state is 31.6 F g -1 , and the specific capacitance in the folding state is 25.3 F g -1 , indicating that the material prepared by the present invention has good flexible energy storage performance. Figure 9 (D) shows the optical images of the flexible woven wearable supercapacitor in different states including twisting, bending, and folding.Figure 9 (E) shows that the stability of the flexible and woven wearable supercapacitor at a current density of 5 Ag -1 is 90.1% after 2000 cycles, demonstrating the excellent electrochemical performance of the prepared flexible and woven wearable supercapacitor.

Claims

1. A polyaniline / thiourea / activated carbon fiber integrated material, characterized in that the material comprises activated carbon fiber (1), thiourea (2) and polyaniline (3); the thiourea (2) is respectively connected to the activated carbon fiber (1) and the polyaniline (2) through a covalent bond (A) and a hydrogen bond (B) to form an integrated structure; one end amino group of the thiourea (2) forms an amide group covalent bond (A) with the carboxyl group of the activated carbon fiber (1), and the other end amino group of the thiourea (2) forms a hydrogen bond (B) with the imino group of the polyaniline (3). One end of the thiourea (2) molecule is connected to the activated carbon fiber (1), and the other end of the thiourea (2) molecule is connected to the polyaniline (3), and the polyaniline / thiourea / activated carbon fiber forms a bridge structure.

2. The polyaniline / thiourea / activated carbon fiber integrated material according to claim 1, characterized in that, The surface of the activated carbon fiber (1) has oxygen-containing functional groups. The activated carbon fiber (1) maintains the fiber bundle structure characteristics of vertical arrangement and close connection, and the polyaniline (3) maintains the nano-column cross-linked structure characteristics.

3. The polyaniline / thiourea / activated carbon fiber integrated material according to claim 1, characterized in that, The molecular model of the activated carbon fiber includes epoxy group, hydroxyl group and carboxyl functional groups. The epoxy group and the hydroxyl group are distributed on the six-membered fused ring of the graphite carbon plane, and the carboxyl group is distributed on the edge of the six-membered fused ring of the graphite carbon plane; the molecular model of the polyaniline is a dimer aniline molecule; the molecular model of the thiourea is that one end amino group of the thiourea is connected to the activated carbon fiber molecule through an amide group covalent bond, and the other end amino group of the thiourea is connected to the polyaniline molecule through a hydrogen bond, constructing a three-component molecular model of the polyaniline / thiourea / activated carbon fiber integrated material.

4. The polyaniline / thiourea / activated carbon fiber integrated material according to claim 1, wherein The polyaniline / thiourea / activated carbon fiber integrated material is subjected to simulation optimization calculation to determine the molecular structure model. Based on the density functional theory calculation of the first principle, the optimized three-component molecular structure is obtained, and the intermolecular distance is obtained. The distance between the imino group of the polyaniline and the amino group of the thiourea is 1.83 Å, and there is a hydrogen bond interface interaction between the polyaniline and the thiourea; an amide group covalent bond is formed between the carboxyl group of the activated carbon fiber and the amino group of the thiourea, and the C-N bond length is 1.394 Å, and there is an amide group covalent bond interface interaction between the activated carbon fiber and the thiourea; the electrostatic potential distribution is obtained, and there is an overlap of the electrostatic potential between the polyaniline and the thiourea, and there is a hydrogen bond interface interaction between the polyaniline and the thiourea; the charge population distribution is obtained. The charge value of the imino nitrogen atom of the polyaniline decreases from -0.597 to -0.638, and the hydrogen atom increases from 0.338 to 0.

429. The charge value of the amino nitrogen atom of the thiourea decreases from -0.705 to -0.822, and there is a hydrogen bond interface interaction between the thiourea and the polyaniline; the charge value of the carboxyl oxygen atom on the activated carbon fiber increases from -0.560 to -0.404, the carbon atom decreases from 0.660 to 0.415, the charge value of the amino nitrogen atom on the thiourea increases from -0.763 to -0.596, and the hydrogen atom increases from 0.374 to 0.

384. There is an amide group covalent bond interaction between the polyaniline and the thiourea.

5. A method for preparing the polyaniline / thiourea / activated carbon fiber integrated material according to any one of claims 1-4, characterized in that, It includes the following steps: (1) Using the hydrothermal activation method and the heat treatment activation method, using carbon fiber as a precursor to prepare activated carbon fiber; (2) Using the grafting synthesis method, using activated carbon fiber as a substrate and adding thiourea to prepare a thiourea / activated carbon fiber integrated material; (3) The electrochemical polymerization method is adopted, using the thiourea / activated carbon fiber integrated material as the substrate, and aniline monomer is added to prepare the polyaniline / thiourea / activated carbon fiber integrated material.

6. The preparation method of the polyaniline / thiourea / activated carbon fiber integrated material according to claim 5, characterized in that, The hydrothermal activation method and heat treatment activation method described in step (1): First, the carbon fiber is pretreated by ultrasonic treatment in an anhydrous ethanol solution for 1-2 hours, and then a nitric acid solution with a mass fraction of 60%-65% is used as the reaction solution, and the carbon fiber is subjected to hydrothermal activation treatment at a temperature of 60-90°C for 12-16 hours. The obtained sample is washed and dried; then heat treatment activation is carried out under a nitrogen atmosphere, the reaction temperature is 500-600°C, and the time is 2-4 h to obtain activated carbon fiber.

7. The preparation method of the polyaniline / thiourea / activated carbon fiber integrated material according to claim 5, characterized in that, The grafting synthesis method described in step (2): Prepare a thiourea solution with a concentration of 0.20-0.25 M, immerse the activated carbon fiber in the thiourea solution, react at a temperature of 80-100°C for 3-5 hours, cool to room temperature, wash and dry to obtain the thiourea / activated carbon fiber integrated material.

8. The preparation method of the polyaniline / thiourea / activated carbon fiber integrated material according to claim 5, characterized in that The electrochemical polymerization method described in step (3): Construct a three-electrode reaction system, configure an aqueous solution containing 1 M sulfuric acid and 0.1 - 0.3 M aniline as the reaction electrolyte solution, and use the thiourea / activated carbon fiber integrated material, platinum sheet, and saturated calomel electrode as the working electrode, counter electrode, and reference electrode respectively. Adopt cyclic voltammetry with a potential window of -0.2 V to 0.8 V and a scanning rate of 5 - 10 mV s -1 . The scanning time is 20 - 25 minutes. After the reaction, wash the working electrode to neutral, dry it, and obtain the polyaniline / thiourea / activated carbon fiber integrated material.

9. Application of the polyaniline / thiourea / activated carbon fiber integrated material described in claim 1 in constructing a flexible and woven wearable supercapacitor for realizing flexible energy storage.

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