Preparation method of wide voltage high flexibility symmetric yarn supercapacitor

Abstract

This invention discloses a method for preparing a wide-voltage, highly flexible symmetrical yarn supercapacitor, belonging to the field of flexible wearable energy storage device technology. The preparation method includes the following steps: S1, preparation of a carbon-based yarn substrate; S2, preparation of an SC@CBY electrode; S3, preparation of a MnO2-SC@CBY composite electrode; S4, preparation of a polyvinyl alcohol / potassium hydroxide gel electrolyte; and S5, preparation of the wide-voltage, highly flexible symmetrical yarn supercapacitor. The wide-voltage, highly flexible symmetrical yarn supercapacitor prepared by this invention has advantages such as a wide operating voltage range, high areal capacitance, high energy density, and long cycle life, maintaining good electrochemical performance output under different bending conditions. It solves the problems of narrow operating voltage windows and low energy density caused by the single energy storage mechanism and poor structural stability of capacitor materials in existing technologies, and has the potential for application in the preparation of wearable electronic devices.

Description

Technical Field

[0001] This invention relates to the field of flexible wearable energy storage device technology, specifically to a method for preparing a wide-voltage, highly flexible symmetrical yarn supercapacitor. Background Technology

[0002] In recent years, wearable and portable electronic devices have experienced explosive growth, creating core demands for flexible, lightweight, and highly safe energy storage power systems to meet their application scenarios. This has become a key driving force for innovation in micro-energy storage technology. Yarn-based aqueous supercapacitors, as highly promising micro-energy storage devices, perfectly meet the power supply needs of wearable and portable electronic products due to their excellent safety, lightweight characteristics, good elasticity and flexibility, and outstanding portability, demonstrating broad application prospects in related fields. However, the commercialization of yarn-based aqueous supercapacitors is still limited by two inherent bottlenecks: a narrow operating voltage window and low energy density. Therefore, widening the operating voltage range and improving electrode specific capacitance have become key paths to overcome existing performance limitations.

[0003] By designing heterostructure electrodes to suppress the HER and OER reactions, and thus inhibit the decomposition of the aqueous electrolyte, the effective voltage broadening in aqueous systems is achieved. This leads to the development of a symmetrical yarn supercapacitor with both high electrochemical performance and high flexibility, becoming a key direction for solving current technological bottlenecks and promoting the large-scale application of yarn-based aqueous supercapacitors. Current electrode materials are mainly divided into two categories: double-layer capacitor materials (such as carbon nanotubes and carbon nanofibers), which possess excellent conductivity, cycle stability, and mechanical properties, but their adsorption / desorption energy storage mechanism results in low specific capacitance and energy density; and pseudocapacitive materials (such as transition metal oxides and conductive polymers), which theoretically have high specific capacitance but suffer from poor conductivity, large volume changes during cycling, and insufficient stability. Therefore, a single material system cannot simultaneously meet the comprehensive requirements of wide voltage range, high energy density, long cycle life, and good flexibility. Thus, achieving synergistic enhancement of double-layer capacitance and pseudocapacitance through heterostructure design has become the core approach to solving these problems.

[0004] Among transition metal oxides, MnO2 is considered an ideal pseudocapacitive material due to its abundant reserves, low cost, non-toxicity, and extremely high theoretical specific capacitance. Meanwhile, sulfur-doped carbon materials possess high specific surface area, good conductivity, and structural stability, making them excellent substrates for double-layer capacitors. Based on the good compatibility of these two materials, a heterostructure electrode with anti-catalytic properties is designed, which is expected to coordinate the Faraday redox reaction of MnO2 with the potential range of the aqueous electrolyte HER / OER, suppressing hydrolysis reactions at high potentials, thereby widening the operating voltage window and achieving simultaneous improvement in specific capacitance and stability.

[0005] To address the aforementioned issues, this invention proposes a heterostructure symmetrical yarn supercapacitor based on an anti-catalysis strategy. By constructing a composite electrode through in-situ growth of an array of S-doped carbon particles and electrodeposition of MnO2 nanosheets, the technical challenges of existing yarn supercapacitors, such as narrow voltage range, low energy density, and insufficient cycle stability, are resolved. Summary of the Invention

[0006] Therefore, this invention provides a method for preparing a wide-voltage, highly flexible, symmetrical yarn supercapacitor to solve the problems of narrow operating voltage window and low energy density caused by the single energy storage mechanism and poor structural stability of the capacitor material in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] According to a first aspect of the present invention, a method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor is provided, comprising the following steps:

[0009] S1. Preparation of carbon-based yarn substrate;

[0010] Preparation of S2 and SC@CBY electrodes;

[0011] Preparation of S3, MnO2-SC@CBY composite electrode;

[0012] S4. Preparation of polyvinyl alcohol / potassium hydroxide gel electrolyte;

[0013] S5. Fabrication of a wide-voltage, high-flexibility symmetrical yarn supercapacitor:

[0014] Two MnO2-SC@CBY composite electrodes were arranged in parallel and encapsulated with polyvinyl alcohol / potassium hydroxide gel electrolyte to obtain a wide-voltage, high-flexibility symmetrical yarn supercapacitor.

[0015] Further, step S1 includes the following steps:

[0016] The original carbon-based yarn was immersed in concentrated nitric acid solution for 48 hours, washed with ultrapure water until neutral, and then dried to obtain the carbon-based yarn substrate.

[0017] Further, step S2 includes the following steps:

[0018] Thioacetamide and ultrapure water were mixed at a mass-to-volume ratio of 3 g:10 mL and stirred until completely dissolved to obtain a thioacetamide solution. The carbon-based yarn substrate obtained in step S1 was immersed in the thioacetamide solution and stirred at 60°C for 24 h. After washing and drying, it was annealed at 350°C for 1.5 h under an argon protective atmosphere to obtain an S-doped carbon particle array modified SC@CBY electrode.

[0019] Furthermore, step S3 includes the following steps:

[0020] A three-electrode system was used for constant current electrodeposition, with SC@CBY as the working electrode, Ag / AgCl as the reference electrode, and Pt as the counter electrode. The electrolyte was a mixed aqueous solution of 0.1 M manganese acetate tetrahydrate and 0.1 M sodium sulfate solution, with a mass ratio of manganese acetate tetrahydrate to sodium sulfate of 1.2:1. The deposition current density was controlled at 0.5 mA / cm². 2 The deposition time was 100-700s to obtain the MnO2-SC@CBY composite electrode.

[0021] Further, step S4 includes the following steps:

[0022] Mix polyvinyl alcohol and ultrapure water at a mass-volume ratio of 1g:20mL, heat and stir at 90℃ until completely dissolved; add potassium hydroxide powder to a final concentration of 1M, continue stirring until a uniform transparent gel is formed, and cool to room temperature for later use.

[0023] Further, step S5 includes the following steps:

[0024] Two MnO2-SC@CBY composite electrodes with identical performance are arranged in parallel. The polyvinyl alcohol / potassium hydroxide gel electrolyte prepared in step S4 is uniformly coated on the electrode surface and gaps. After encapsulation with an encapsulation layer, a wide voltage, high flexibility, and symmetrical yarn supercapacitor is obtained.

[0025] According to a second aspect of the present invention, a wide-voltage, high-flexibility symmetrical yarn supercapacitor is provided, comprising a symmetrical MnO2-SC@CBY composite electrode as the positive and negative electrodes, a polyvinyl alcohol / potassium hydroxide gel electrolyte as the electrolyte, and an encapsulation layer.

[0026] Furthermore, the MnO2-SC@CBY composite electrode is composed of a three-layer heterostructure: a carbon-based yarn substrate, an S-doped carbon particle nanoarray, and MnO2 nanosheets. The operating voltage window of the symmetrical yarn supercapacitor is 1.5V, and the specific surface area of ​​the composite electrode is 300-400m². 2 / g, with a main pore size distribution of 3.1-29.8nm, exhibiting a mesoporous structure; the concentration of potassium hydroxide in the polyvinyl alcohol / potassium hydroxide is 1M; the encapsulation layer has a thickness of 50-100μm and is made of a flexible insulating polymer.

[0027] Furthermore, the yarn diameter of the carbon-based yarn substrate is 10-20 μm; the S-doped carbon particle array has a thickness of 600 nm and is uniformly grown on the surface of the carbon-based yarn substrate.

[0028] According to a third aspect of the present invention, an application of a wide-voltage, high-flexibility symmetrical yarn supercapacitor in the fabrication of wearable electronic devices is provided.

[0029] The present invention has the following advantages:

[0030] (1) Wide operating voltage window: By coordinating the Faraday redox reaction of MnO2 with the HER / OER potential range through the anti-catalysis strategy, the hydrolysis reaction in the aqueous electrolyte is effectively suppressed, and the operating voltage of the device is widened to 1.5V, which far exceeds the 1.23V voltage limit of the traditional aqueous solution system;

[0031] (2) High energy density and specific capacitance: At a current density of 1 mA / cm², the device area capacitance reaches 69.1 mF / cm², corresponding to an energy density of 21.6 μWh / cm² (power density of 14.7 mW / cm²). When the power density is increased to 59.1 mW / cm², the energy density remains at 17.7 μWh / cm², which is better than most reported yarn-based supercapacitors.

[0032] (3) Excellent cycle stability: After 15,000 charge-discharge cycles at a current density of 8 mA / cm², the capacitance retention rate is 88.97%, and the electrode microstructure is not significantly damaged after cycling, and the electrochemical impedance remains basically unchanged.

[0033] (4) Good flexibility: The CV curve shape of the device remains basically unchanged under different bending angles such as 0°, 45°, 90°, and 135°, and the electrochemical performance is stable, meeting the bending and wrapping requirements of wearable devices.

[0034] (5) The preparation process is simple and controllable: simple processes such as soaking, annealing, and electrodeposition are adopted. The operation is simple and the cost is low. The key process parameters such as deposition time and annealing temperature are easy to control, which is suitable for large-scale production.

[0035] This invention achieves the synergistic effect of double-layer capacitance and pseudocapacitance through heterostructure design, and overcomes the voltage limitation of aqueous electrolyte system by means of anti-catalysis strategy. It provides a practical technical solution for the preparation of wide voltage, high energy density flexible yarn supercapacitors, which can be widely used in wearable electronics, smart textiles, portable sensors and other fields. Attached Figure Description

[0036] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0037] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0038] Figure 1 The SC@CBY electrode provided in Embodiment 1 of the present invention is shown in scanning electron microscope images at the 5 μm and 1 μm scales;

[0039] Figure 2 The images are scanning electron microscope images of the MnO2-SC@CBY composite electrode provided in Example 1 of this invention at the 5μm and 1μm scales.

[0040] Figure 3 These are scanning electron microscope (SEM) images of the MnO2-SC@CBY composite electrodes provided in Examples 1-4 of this invention at the 5 μm and 500 nm scales.

[0041] Figure 4 This is a transmission electron microscope (TEM) image of the MnO2-SC@CBY composite electrode provided in Example 1 of the present invention at a 2 nm scale.

[0042] Figure 5 Cyclic voltammetry curves of the SC@CBY electrode under different voltages provided in Embodiment 1 of the present invention;

[0043] Figure 6 Linear sweep voltammetry curves of the MnO2-SC@CBY composite electrode provided in Embodiment 1 of the present invention at different voltages;

[0044] Figure 7 The MnO2-SC@CBY symmetrical yarn supercapacitor provided in Embodiment 1 of this invention operates at 1-5 mA·cm⁻¹. -2 The timing potential curve is shown below;

[0045] Figure 8 This is a cycle count-capacitance retention rate diagram of the MnO2-SC@CBY symmetrical yarn supercapacitor provided in Embodiment 1 of the present invention;

[0046] Figure 9 EIS curves of the MnO2-SC@CBY symmetrical yarn supercapacitor provided in Embodiment 1 of the present invention before and after 15,000 cycles;

[0047] Figure 10Cyclic volt-ampere curves of the MnO2-SC@CBY symmetrical yarn supercapacitor provided in Embodiment 1 of the present invention at bending angles of 0°, 45°, 90° and 135°.

[0048] Figure 11 This is an application diagram of the wide-voltage, high-flexibility symmetrical yarn supercapacitor provided by the present invention. Detailed Implementation

[0049] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] According to a first aspect of the present invention, a method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor is provided, comprising the following steps:

[0051] S1. Preparation of carbon-based yarn substrate;

[0052] Preparation of S2 and SC@CBY electrodes;

[0053] Preparation of S3, MnO2-SC@CBY composite electrode;

[0054] S4. Preparation of polyvinyl alcohol / potassium hydroxide gel electrolyte;

[0055] S5. Fabrication of a wide-voltage, high-flexibility symmetrical yarn supercapacitor:

[0056] Two MnO2-SC@CBY composite electrodes were arranged in parallel and encapsulated with polyvinyl alcohol / potassium hydroxide gel electrolyte to obtain a wide-voltage, high-flexibility symmetrical yarn supercapacitor.

[0057] Step S1 includes the following steps:

[0058] The original carbon-based yarn was immersed in concentrated nitric acid solution for 48 hours, washed with ultrapure water until neutral, and then dried to obtain the carbon-based yarn substrate.

[0059] Step S2 includes the following steps:

[0060] Thioacetamide and ultrapure water were mixed at a mass-to-volume ratio of 3 g:10 mL and stirred until completely dissolved to obtain a thioacetamide solution. The carbon-based yarn substrate obtained in step S1 was immersed in the thioacetamide solution and stirred at 60°C for 24 h. After washing and drying, it was annealed at 350°C for 1.5 h under an argon protective atmosphere to obtain an S-doped carbon particle array modified SC@CBY electrode.

[0061] Step S3 includes the following steps:

[0062] A three-electrode system was used for constant current electrodeposition, with SC@CBY as the working electrode, Ag / AgCl as the reference electrode, and Pt as the counter electrode. The electrolyte was a mixed aqueous solution of 0.1 M manganese acetate tetrahydrate and 0.1 M sodium sulfate solution, with a mass ratio of manganese acetate tetrahydrate to sodium sulfate of 1.2:1. The deposition current density was controlled at 0.5 mA / cm². 2 The deposition time was 100-700s to obtain the MnO2-SC@CBY composite electrode.

[0063] Step S4 includes the following steps:

[0064] Mix polyvinyl alcohol and ultrapure water at a mass-volume ratio of 1g:20mL, heat and stir at 90℃ until completely dissolved; add potassium hydroxide powder to a final concentration of 1M, continue stirring until a uniform transparent gel is formed, and cool to room temperature for later use.

[0065] Step S5 includes the following steps:

[0066] Two MnO2-SC@CBY composite electrodes with identical performance are arranged in parallel. The polyvinyl alcohol / potassium hydroxide gel electrolyte prepared in step S4 is uniformly coated on the electrode surface and gaps. After encapsulation with an encapsulation layer, a wide voltage, high flexibility, and symmetrical yarn supercapacitor is obtained.

[0067] According to a second aspect of the present invention, a wide-voltage, high-flexibility symmetrical yarn supercapacitor is provided, comprising a symmetrical MnO2-SC@CBY composite electrode as the positive and negative electrodes, a polyvinyl alcohol / potassium hydroxide gel electrolyte as the electrolyte, and an encapsulation layer.

[0068] The MnO2-SC@CBY composite electrode is composed of a three-layer heterostructure: a carbon-based yarn substrate, an S-doped carbon particle nanoarray, and MnO2 nanosheets. The symmetrical yarn supercapacitor has a working voltage window of 1.5V, and the composite electrode has a specific surface area of ​​300-400 m². 2 / g, with a main pore size distribution of 3.1-29.8nm, exhibiting a mesoporous structure; the concentration of potassium hydroxide in the polyvinyl alcohol / potassium hydroxide mixture is 1M; the encapsulation layer thickness is 50-100μm, and the material is a flexible insulating polymer.

[0069] The yarn diameter of the carbon-based yarn substrate is 10-20 μm; the S-doped carbon particle array has a thickness of 600 nm and is uniformly grown on the surface of the carbon-based yarn substrate.

[0070] To better illustrate the innovation and technical approach of this invention, the following embodiments are provided.

[0071] Example 1

[0072] S1. Preparation of carbon-based yarn substrate:

[0073] The original carbon-based yarn was immersed in concentrated nitric acid solution for 48 hours, washed with ultrapure water until neutral, and then dried to obtain carbon-based yarn substrate (CBY).

[0074] Preparation of S2 and SC@CBY electrodes:

[0075] 3.00 g of thioacetamide (C2H5NS) was dispersed in 10 mL of ultrapure water. CBY was immersed in the solution and stirred at 60 °C for 24 h. After removal, washing and drying, the electrode was annealed at 350 °C for 1.5 h under Ar atmosphere to obtain an S-doped carbon particle array modified SC@CBY electrode.

[0076] Preparation of S3, MnO2-SC@CBY composite electrode:

[0077] A three-electrode system was used for constant current electrodeposition, with SC@CBY as the working electrode, Ag / AgCl as the reference electrode, and Pt as the counter electrode. 12 g of manganese acetate tetrahydrate and 10 g of sodium sulfate were dissolved separately in deionized water to a final concentration of 0.1 M, and the mixture was used as the electrodeposition electrolyte. The deposition current density was controlled at 0.5 mA / cm². 2 The deposition time was 500 s, and the MnO2-SC@CBY composite electrode was obtained.

[0078] S4. Preparation of polyvinyl alcohol / potassium hydroxide gel electrolyte:

[0079] Mix 1g of polyvinyl alcohol with 20mL of ultrapure water, heat and stir at 90℃ until completely dissolved; add 1.1g of potassium hydroxide powder to a final concentration of 1M, continue stirring until a uniform transparent gel is formed, and cool to room temperature for later use.

[0080] S5. Fabrication of a wide-voltage, high-flexibility symmetrical yarn supercapacitor:

[0081] Two MnO2-SC@CBY composite electrodes with identical performance are arranged in parallel. The polyvinyl alcohol / potassium hydroxide gel electrolyte prepared in step S4 is uniformly coated on the electrode surface and gaps. After being encapsulated by a transparent plastic sheath, a wide voltage, high flexibility, and symmetrical yarn supercapacitor is obtained.

[0082] Example 2

[0083] This embodiment is based on embodiment 1, except that the deposition time in step S3 is 100s, while the other specific parameters are the same as in embodiment 1.

[0084] Example 3

[0085] This embodiment is based on Embodiment 1, except that the deposition time in step S3 is 300s, while the other specific parameters are the same as in Embodiment 1.

[0086] Example 4

[0087] This embodiment is based on Embodiment 1, except that the deposition time in step S3 is 700s, while the other specific parameters are the same as in Embodiment 1.

[0088] Test Example 1

[0089] The surface morphology of the SC@CBY electrode prepared in Example 1 and the MnO2-SC@CBY composite electrode prepared in Examples 1-4 were observed by scanning electron microscopy in this invention.

[0090] Figure 1 and Figure 2 The images are scanning electron microscope (SEM) images of the SC@CBY electrode and the MnO2-SC@CBY composite electrode provided in Example 1 of the present invention at the 5 μm and 1 μm scales, respectively. Figure 3 The images show scanning electron microscope (SEM) images of the MnO2-SC@CBY composite electrodes provided in Examples 1-4 of this invention at the 5 μm and 500 nm scales. It can be seen that the S-doped C nanoparticle array is grown in situ on the yarn substrate surface of the SC@CBY electrode prepared in Example 1. The MnO2 nanosheets deposited on the surface of the MnO2-SC@CBY composite electrode are uniformly and continuously distributed. However, the MnO2 coverage on the surface of the MnO2-SC@CBY composite electrodes obtained by deposition for 100 s and 300 s is sparse, and the composite electrode obtained by deposition for 700 s exhibits MnO2 agglomeration.

[0091] Test Example 2

[0092] The specific morphology of the MnO2-SC@CBY composite electrode prepared in Example 1 was observed by transmission electron microscopy. Figure 4 The image shows a transmission electron microscope (TEM) image of the MnO2-SC@CBY composite electrode provided in Example 1 of this invention at a 2 nm scale. It can be seen that the MnO2 phase in the prepared composite electrode exhibits good crystallinity, with lattice fringe spacings of 0.487 nm, 0.246 nm, and 0.305 nm, respectively. The (200), (211), and (310) crystal planes of α-MnO2 are highly consistent. The clearly visible heterojunction interface in the image confirms the successful construction of the heterostructure. This structure can effectively promote interfacial charge transfer and separation, providing crucial structural support for improving the performance of the material in fields such as supercapacitors and electrocatalysis.

[0093] Test Example 3

[0094] To verify the electrochemical performance of the SC@CBY electrode, the MnO2-SC@CBY composite electrode, and the MnO2-SC@CBY symmetrical yarn supercapacitor, the cyclic voltammetry curves of the SC@CBY electrode, the linear sweep voltammetry curves of the MnO2-SC@CBY composite electrode, and the cycle-capacitance retention rate, EIS curves, chronopotential curves, and cyclic voltammetry curves at bending angles of 0°, 45°, 90°, and 135° of the MnO2-SC@CBY symmetrical yarn supercapacitor were measured.

[0095] Figure 5 Cyclic voltammetry curves of the SC@CBY electrode provided in Embodiment 1 of this invention at voltages of 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 V are shown. It can be seen that when the anode voltage exceeds +0.2 V, the oxidation current begins to rise sharply, which is a typical characteristic of water decomposition, indicating that this potential is the critical potential for the SC@CBY electrode to trigger water decomposition side reactions. As the upper limit oxidation voltage increases from 1.0 V to 1.5 V, the current density in the water decomposition region increases significantly, indicating that a higher anode potential accelerates the oxidative decomposition of water, and the side reaction rate increases significantly with increasing potential. The potential range without significant side reactions in the figure represents the effective stable operating window; it can be seen that the voltage operating window of the SC@CBY electrode is only 1 V.

[0096] Figure 6 The linear sweep voltammetry (LSV) curves of the MnO2-SC@CBY composite electrode provided in Example 1 of this invention at different voltages are shown. The LSV test reveals that the MnO2-SC@CBY composite electrode exhibits a large negative current of -30 mA in the range of -1.5 V to -1.0 V, which is a typical characteristic of the hydrogen evolution reaction. When the potential is below -1.0 V, the H2O / H2O ratio in the electrolyte... + When reduced to H2, the current increases sharply, indicating an uncontrolled side reaction that exceeds the capacitor's stable operating window. The composite electrode exhibits a nearly flat current (close to 0) in the -1.0V to +0.5V range, displaying anti-catalytic characteristics and indicating the absence of significant water splitting side reactions. This is typical double-layer capacitance behavior, demonstrating that the composite electrode maintains a stable current response within the 1.5V range, far exceeding the theoretical decomposition voltage of 1.23V for aqueous electrolytes.

[0097] Figure 7 The MnO2-SC@CBY symmetrical yarn supercapacitor provided in Embodiment 1 of this invention operates at 1-5 mA·cm⁻¹. -2 The timing potential curve below. Figure 7 And the formula: (1) (2) (3) Calculations show that, at a current density of 1 mA / cm², the areal capacitance of the symmetrical yarn supercapacitor reaches 69.1 mF / cm².2 The energy density is 21.6 μWh / cm³. 2 (Power density 14.7 mW / cm³) 2 Furthermore, it exhibits the longest discharge time, indicating that at low current densities, the device has a longer charge storage time and a larger areal capacitance; Figure 8 and Figure 9 It can be seen that the capacitance retention rate of the symmetrical yarn supercapacitor is 88.97% after 15,000 cycles, and the EIS curve shows that the charge transport impedance remains basically unchanged after cycling; Figure 10 It can be seen that at 50mV·s -1 The CV curve shape remains stable under voltage change rate and bending angle of 0°–135°, indicating that the device has excellent mechanical durability.

[0098] Figure 11 The figure shows an application diagram of the wide-voltage, high-flexibility symmetrical yarn supercapacitor provided by this invention. As shown in the figure, the wide-voltage, high-flexibility symmetrical yarn supercapacitor prepared by this invention can be used in sportswear or protective gear. On the one hand, it can collect the mechanical energy generated by human movement to power devices such as sensors; on the other hand, it can be used as a flexible sensor to capture human data, assisting in motion behavior analysis or health management. This invention also has good flexibility, fit, and weavability, and can be used to prepare everyday wearable electronic devices. It can be directly woven into clothing, accessories, etc., to continuously power small electronic devices within them.

[0099] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor, characterized in that, Includes the following steps: S1. Preparation of carbon-based yarn substrate; Preparation of S2 and SC@CBY electrodes: Thioacetamide and ultrapure water were mixed at a mass-volume ratio of 3g:10mL and stirred until completely dissolved to obtain a thioacetamide solution. The carbon-based yarn substrate obtained in step S1 was immersed in the thioacetamide solution and stirred at 60°C for 24h. After washing and drying, it was annealed at 350°C for 1.5h under an argon protective atmosphere to obtain a carbon-based yarn substrate SC@CBY electrode modified with an S-doped carbon particle array. Preparation of S3, MnO2-SC@CBY composite electrode; S4. Preparation of polyvinyl alcohol / potassium hydroxide gel electrolyte; S5. Fabrication of a wide-voltage, high-flexibility symmetrical yarn supercapacitor: Two MnO2-SC@CBY composite electrodes were arranged in parallel and encapsulated with polyvinyl alcohol / potassium hydroxide gel electrolyte to obtain a wide-voltage, high-flexibility symmetrical yarn supercapacitor.

2. The method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 1, characterized in that, Step S1 includes the following steps: The original carbon-based yarn was immersed in concentrated nitric acid solution for 48 hours, washed with ultrapure water until neutral, and then dried to obtain the carbon-based yarn substrate.

3. The method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 1, characterized in that, Step S3 includes the following steps: The constant current electrodeposition is carried out by adopting a three-electrode system, SC@CBY is used as a working electrode, Ag / AgCl is used as a reference electrode, and Pt is used as a counter electrode; the electrolyte is a mixed aqueous solution of 0.1M manganese acetate tetrahydrate solution and 0.1M sodium sulfate solution, wherein the mass ratio of manganese acetate tetrahydrate to sodium sulfate is 1.2:1; the deposition current density is controlled to be 0.5mA / cm 2 , and the deposition time is 100-700s, so that the MnO2-SC@CBY composite electrode is obtained.

4. The method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 1, characterized in that, Step S4 includes the following steps: Mix polyvinyl alcohol and ultrapure water at a mass-volume ratio of 1g:20mL, heat and stir at 90℃ until completely dissolved; add potassium hydroxide powder to a final concentration of 1M, continue stirring until a uniform transparent gel is formed, and cool to room temperature for later use.

5. The method for preparing a wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 1, characterized in that, Step S5 includes the following steps: Two MnO2-SC@CBY composite electrodes with identical performance are arranged in parallel. The polyvinyl alcohol / potassium hydroxide gel electrolyte prepared in step S4 is uniformly coated on the electrode surface and gaps. After encapsulation with an encapsulation layer, a wide voltage, high flexibility, and symmetrical yarn supercapacitor is obtained.

6. A wide-voltage, high-flexibility symmetrical yarn supercapacitor, prepared by the method according to any one of claims 1-5, characterized in that, It consists of a symmetrical MnO2-SC@CBY composite electrode as the positive and negative electrodes, a polyvinyl alcohol / potassium hydroxide gel electrolyte as the electrolyte, and an encapsulation layer.

7. A wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 6, characterized in that, The MnO2-SC@CBY composite electrode is composed of a three-layer heterostructure: a carbon-based yarn substrate, an S-doped carbon particle nanoarray, and MnO2 nanosheets. The operating voltage window of the symmetrical yarn supercapacitor is 1.5V, and the specific surface area of ​​the composite electrode is 300-400m². 2 / g, with a main pore size distribution of 3.1-29.8nm, exhibiting a mesoporous structure; the concentration of potassium hydroxide in the polyvinyl alcohol / potassium hydroxide is 1M; the encapsulation layer has a thickness of 50-100μm and is made of a flexible insulating polymer.

8. A wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 7, characterized in that, The diameter of the yarn in the carbon-based yarn substrate is 10-20 μm; the thickness of the S-doped carbon particle array is 600 nm, and it is uniformly grown on the surface of the carbon-based yarn substrate.

9. The application of the wide-voltage, high-flexibility symmetrical yarn supercapacitor as described in claim 6 in the fabrication of wearable electronic devices.

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