Self-repairing flexible supercapacitor based on double dynamic keys and preparation method thereof

Abstract

The invention discloses a self-repairing flexible supercapacitor based on double dynamic bonds and a preparation method thereof, and the method comprises the steps: taking limonene (LIM) and lipoic acid (LA) as monomers, and carrying out one-pot polymerization to form a three-dimensional porous gel network P (LA-LIM) based on the synergistic effect of double dynamic bonds of hydrogen bonds and disulfide bonds; the multifunctional polymer gel P (LA-LIM)-IL with good flexibility, self-healing property and ionic conductivity is prepared by further introducing ionic liquid (ILs), and the flexible symmetric supercapacitor assembled by taking nitrogen-doped porous carbon (N-C) as an electrode shows excellent self-repairing property and environmental adaptability. The method is simple and convenient in process and low in cost, and has important practical value in the field of flexible energy storage devices.

Description

Technical Field

[0001] This invention belongs to the field of flexible energy storage device fabrication technology, specifically relating to a self-healing flexible supercapacitor based on dual dynamic bonds and its fabrication method. Background Technology

[0002] Against the backdrop of the deep integration of flexible electronics technology and energy storage, flexible supercapacitors, with their excellent charging and discharging speeds, long lifespans, and high safety, have demonstrated enormous application potential in cutting-edge scenarios such as wearable devices and implantable medical devices. Gel materials, due to their good flexibility, high conductivity, and portability, have become an ideal choice for constructing electrolytes for flexible supercapacitors. However, in practical applications, these devices must withstand complex working environments such as frequent bending and stretching, inevitably leading to irreversible physical damage such as breakage and fracture, severely affecting the electrochemical performance of the devices. Simultaneously, outdoor and cold-weather environments place higher demands on the weather resistance of the devices. Traditional water-based gel electrolytes are prone to problems such as a sharp drop in conductivity and gel hardening due to water evaporation and freezing, which further limit their application range.

[0003] Imbuing devices with self-healing properties is an effective strategy to overcome mechanical damage and extend their lifespan. Traditional self-healing supercapacitors rely on physical cross-linking mechanisms (such as hydrogen bonds) for repair in their gel electrolytes. However, these non-covalent bonds have weak bond energies, resulting in limited gel mechanical strength and significant performance degradation after repeated repairs. Furthermore, the preparation of some self-healing gel electrolytes involves complex steps (such as multi-step cross-linking and high-temperature treatment), leading to high production costs and difficulties in large-scale production. In addition, the assembly of electrodes and electrolytes requires additional adhesives, which increases interfacial resistance and weakens the overall flexibility of the device, further limiting its practical applications.

[0004] In addition to imparting self-healing properties to the gel electrolyte, the stability of the gel over a wide operating temperature range is also a key factor affecting the device.

[0005] Therefore, developing a method for preparing a self-healing flexible supercapacitor that combines antifreeze properties, simple process, and no need for additional adhesives is of great significance for promoting the practical application of flexible energy storage devices. This method can achieve high-efficiency self-healing performance, solve mechanical strength and low-temperature failure problems, simplify the production process, and reduce costs. Summary of the Invention

[0006] This invention aims to overcome the key defects of existing flexible supercapacitors in practical applications, including: low self-healing efficiency and insufficient mechanical strength of traditional gel electrolytes; water-based systems are prone to freezing and failure at low temperatures, making them difficult to adapt to wide temperature range environments; and complex preparation processes, requiring additional adhesives for assembly, resulting in high costs and large interfacial resistance.

[0007] This invention provides a self-healing flexible supercapacitor based on dual dynamic bonds. The capacitor includes a gel electrolyte and two symmetrical electrodes. The gel electrolyte is a P(LA-LIM)-IL ionic gel electrolyte, which is prepared by ring-opening polymerization and cross-linking of lipoic acid (LA) and limonene (LIM) to form a three-dimensional porous network containing dynamic disulfide bonds and hydrogen bonds, and then introducing ionic liquids (ILs). The electrodes contain nitrogen-doped porous carbon electrode active material (NC material), which is formed by carbonization of nano-zeolite imidazole acid framework-8 (nZIF-8) and nano-cellulose. The gel electrolyte and the two symmetrical electrodes form a sandwich structure with the gel electrolyte as the core through self-adhesion.

[0008] This capacitor achieves self-healing through the synergistic effect of dual dynamic bonds (physical crosslinking and dynamic covalent bonds), possesses antifreeze properties, requires no additional adhesives, and has a simple fabrication process. It achieves highly efficient self-healing performance, solves mechanical strength and low-temperature failure issues, simplifies production processes, and reduces costs, which is of great significance for promoting the practical application of flexible energy storage devices. The gel electrolyte used in this invention contains dynamic disulfide bonds with higher bond energies than non-covalent bonds, enabling reversible bond breakage and recombination without external stimulation. Furthermore, the introduced ionic liquid has a low melting point and high ionic conductivity, allowing the electrolyte to achieve self-healing over a wide temperature range (-20-80℃) and endowing it with excellent antifreeze properties, thus demonstrating unique potential in the field of antifreeze technology and meeting the requirements of long-cycle and extreme operating environments for flexible electronic products.

[0009] Preferably, the nano-zeolite imidazole acid framework-8 is prepared by a self-assembly-co-crystallization reaction of hexadecyltrimethylammonium bromide (CTAB), 2-methylimidazole (2-MiM) and a zinc-containing compound.

[0010] Preferably, the zinc-containing compound is zinc acetate dihydrate.

[0011] Preferably, the ionic liquid is ethyl 1-ethyl-3-methylimidazolium sulfate.

[0012] This invention also provides a method for fabricating a self-healing flexible supercapacitor based on dual dynamic bonds, comprising:

[0013] Step 1, Preparation of gel electrolyte: Dissolve lipoic acid in an organic solvent, then add ethyl 1-ethyl-3-methylimidazolium sulfate, stir evenly, and slowly add limonene while continuing to stir until the solution viscosity increases. After the organic solvent evaporates, an ionic gel can be obtained. After gelation, soak in an ionic liquid to obtain P(LA-LIM)-IL gel electrolyte; wherein the molar ratio of lipoic acid to limonene is 1:(0.005-0.2), preferably 1:(0.05-0.2).

[0014] Step 2, Preparation of symmetrical electrode: Nitrogen-doped porous carbon electrode active material, conductive agent and binder are mixed and coated on flexible current collector, and dried to obtain electrode; wherein the preparation method of the nitrogen-doped porous carbon electrode active material includes: (1) mixing hexadecyltrimethylammonium bromide solution and 2-methylimidazole solution and then adding zinc compound solution, letting stand and centrifuging; (2) washing the solid product and drying to obtain nZIF-8; (3) combining nZIF-8 with nanocellulose and then performing directional freeze-drying; (4) heating to 800-1000℃ under nitrogen atmosphere for carbonization, washing and drying to obtain nitrogen-doped porous carbon;

[0015] Step 3: Assemble the capacitor: Sandwich the gel electrolyte between two symmetrical electrodes and press them together to form a sandwich structure, thus obtaining the self-healing flexible supercapacitor based on dual dynamic bonds.

[0016] According to the preparation method described above, preferably, the flexible current collector is a hydrophilic conductive carbon cloth.

[0017] According to the preparation method described above, preferably, the conductive agent is acetylene black, and the binder is polyvinylidene fluoride; in the electrode preparation raw materials, the mass ratio of nitrogen-doped porous carbon electrode active material: acetylene black: polyvinylidene fluoride is 8:1:1.

[0018] According to the preparation method described above, preferably, the loading amount of the nitrogen-doped porous carbon electrode active material on the flexible carbon cloth is approximately 4 mg cm⁻¹. -2 .

[0019] Specifically, a method for fabricating a self-healing flexible supercapacitor based on dual dynamic bonds includes:

[0020] Step 1: Prepare P(LA-LIM)-IL gel electrolyte by dissolving 1–3 g of lipoic acid in 2–5 mL of anhydrous ethanol to obtain a yellow transparent solution, and then adding 0.25–0.75 mol L... -1 1-Ethyl-3-methylimidazolium sulfate ethyl ester, stirred for 3–5 min, then slowly added dropwise at 0.125–0.5 mol / L. -1 After stirring limonene for 2-5 minutes, the solution viscosity increases. The mixed sol is then poured into a polytetrafluoroethylene mold. After the ethanol evaporates, an ionic gel is obtained. After gelation, the ionic liquid is soaked in the gel to obtain P(LA-LIM)-IL gel electrolyte.

[0021] Step 2: Preparation of active material NC. Dissolve 100 mg cetyltrimethylammonium bromide, 28 g 2-methylimidazole, and 6 g zinc acetate dihydrate in 100 mL of deionized water. Mix 1 g of CTAB solution with 5.1 g of 2-MiM solution, then add 5.3 g of zinc acetate dihydrate solution to obtain a white, homogeneous emulsion. After standing for 1.5–2.5 h, centrifuge (9000–11000 rpm, 5–15 min), discard the supernatant, wash the solid product, and dry at 80 °C for 12–24 h to obtain nZIF-8 white powder. Combine nZIF-8 with 1 wt.% nanocellulose to form a nano-zeolite imidazole acid backbone-8 mixed gel with a concentration of 0.2–0.3 wt.%. After directional freeze-drying and lyophilization, refrigerate at 3–10 °C for 1 min under a nitrogen atmosphere. -1 The temperature is increased to 800-1000℃ and carbonized for 2.5-3.5 hours. After washing and drying, NC material is obtained.

[0022] Step 3: Weigh the nitrogen-doped porous carbon, acetylene black, and polyvinylidene fluoride obtained in Step 2 in a mass ratio of 8:1:1, grind them evenly in a mortar, add a small amount of N-methylpyrrolidone, stir to form a slurry, coat it onto a hydrophilic conductive carbon cloth, and dry it at 60°C for 12–24 hours. Sandwich the gel electrolyte from Step 1 between the two electrodes and press them together to form a sandwich structure, thus obtaining a self-healing flexible supercapacitor.

[0023] Preferably, CTAB (0.2 mg / mL) is used. -1 The solid product was washed with deionized water and dried to obtain nZIF-8 white powder; the carbonized solid product was washed multiple times with 1M HCl solution and DI water until pH=7 and then dried to obtain NC material.

[0024] For example, the gel electrolyte prepared in step 1 has a size of 1cm × 1.5cm × 2mm. Then, the 1cm × 2cm electrodes prepared in step 3 above are attached to the upper and lower end faces of the hydrogel electrolyte, so that the facing area of ​​the two electrodes is 1 × 1.5cm. 2 The dimensions of the "three-layer structure" supercapacitor assembled in step 3 are for testing purposes; in the practical application stage, the dimensions can be arbitrary.

[0025] In step 2, CTAB solution (0.2 mg / mL) is used. -1 The solid product was washed with deionized water and dried to obtain nZIF-8 white powder; the carbonized solid product was washed multiple times with 1M HCl solution and DI water until pH=7 and then dried to obtain NC material.

[0026] The core of this invention is to achieve low-cost fabrication of self-healing flexible supercapacitors through a "one-pot gel synthesis—derived carbon electrode preparation—self-adhesive assembly" process. First, a dual-dynamic bond gel network is constructed using a one-pot method: the 1,2-dithiopentane in the LA monomer molecule undergoes ring-opening polymerization to form a polythiooctanoic acid (PLA) substrate containing dynamic disulfide bonds and intermolecular hydrogen bonds. Subsequently, LIM is introduced to quench terminal sulfur radicals and, through synergistic interaction with the PLA backbone, crosslink the network, thereby improving the material's mechanical properties. Second, the introduction of the ionic liquid 1-ethyl-3-methylimidazolium sulfate ethyl ester (IL, [EMIM][ESO4]) achieves multiple functional optimizations: it not only effectively inhibits gel dehydration and low-temperature freezing, thus broadening the operating temperature range; [ESO4]... - Furthermore, it can form additional hydrogen bonds with the carboxylic acid groups of PLA, further strengthening the network structure and enabling the gel to possess both high ionic conductivity and efficient self-healing properties. Moreover, the capacitive active material is derived from high-conductivity flexible carbon material. Using nZIF-8 as a precursor, it is composited with nanocellulose and then subjected to directional freezing and high-temperature carbonization to form a high-porosity nitrogen-doped carbon material. Its surface functional groups can form hydrogen bonds with the gel electrolyte, significantly enhancing interfacial bonding. Finally, utilizing the self-adhesive properties of the gel electrolyte, the aforementioned nitrogen-doped carbon electrode is directly pressed onto the gel to form a sandwich structure, completing the device fabrication without the need for additional adhesives.

[0027] The present invention has the following beneficial effects:

[0028] (1) The P(LA-LIM)-IL gel electrolyte prepared in this invention exhibits excellent self-healing ability, flexibility, and strong adhesion. This gel has good flexibility, allowing for bending and stretching operations, with an elongation of up to 350%; it also possesses rapid self-healing ability, healing within 30 seconds of being cut. Its excellent self-healing properties can be attributed to the abundant dynamic disulfide bonds, hydrogen bonds, and electrostatic interactions in the three-dimensional cross-linked network of P(LA-LIM)-IL, promoting a rapid and reversible physical / chemical bonding process at room temperature. Benefiting from the synergistic effect of disulfide bonds, hydrogen bonds, and the electrostatic interaction between IL and thioctic acid carboxylic acid groups, the P(LA-LIM)-IL gel exhibits strong adhesion on plastic, glass, rubber, and metal substrates. Its flexibility stems from the extensibility provided by the flexible main chain containing sulfur segments, and the energy dissipation through the abundant hydrogen bonds in the system acting as sacrificial bonds. During stretching, the polymer chains untangle; due to the cross-linking effect between LIM and PLA, energy is dissipated and the integrity of the network is maintained when external force is applied.

[0029] (2) The low melting point and low saturated vapor pressure of ILs endow the ion gel with excellent antifreeze properties. The P(LA-LIM)-IL ion gel prepared in this invention can still maintain good extensibility after being frozen for 6 hours in a low temperature environment of -20℃.

[0030] (3) The NC / / P(LA-LIM)-IL / / NC(CPCSCs) symmetrical flexible device prepared by this invention is formed by tightly bonding the P(LA-LIM)-IL electrolyte and the NC electrode through hydrogen bonding and interface-induced non-covalent bonding, which enables the device to maintain interface stability during repeated deformation. After 100 mechanical deformations, it retains more than 85% of its performance; after 20 cutting / healing cycles, the capacitance can still recover more than 92% of its original capacitance.

[0031] (4) The raw materials used in this invention are readily available. The gel is synthesized in one pot and the electrode is prepared by carbonization in one step. Assembly can be completed without additional adhesives, which significantly simplifies the production process, reduces equipment investment and production costs, and is suitable for large-scale mass production. Attached Figure Description

[0032] Figure 1 Scanning electron microscope image of the P(LA-LIM)-IL gel prepared in Example 1.

[0033] Figure 2 Electrochemical test results of CPCSCs supercapacitors prepared in Example 5: (a) Cyclic voltammetry curves of CPCSCs at different scan rates and (b) Constant current charge-discharge curves at different current densities.

[0034] Figure 3 GCD curves of CPCSCs prepared in Example 5 in the temperature range of -10 to 50°C.

[0035] Figure 4 Electrochemical test results of CPCSCs supercapacitors prepared in Example 5 after different mechanical deformations (including bending and torsion): (a) CV curve, (b) GCD curve, (c) capacitance retention.

[0036] Figure 5 GCD curves and capacitance retention rates of CPCSCs prepared in Example 5 after 20 cuts / self-healing.

[0037] Figure 6 Photograph of the self-healing P(LA-LIM)-IL gel electrolyte prepared in Example 1 at room temperature. Detailed Implementation

[0038] Example 1: Preparation of P(LA-LIM)-IL gel electrolyte

[0039] Ionic gels were prepared at room temperature via high-concentration LA-induced ring-opening polymerization. LA (2.0 g) was dissolved in anhydrous ethanol (4.0 mL) to obtain a yellow transparent solution. A certain amount of [EMIM][ESO4] was added, and after stirring for 5 min, LIM, LA, LIM, and [EMIM][ESO4] were slowly added dropwise in a molar ratio of 10:1:2. After stirring for 2 min, the solution viscosity increased. After the reaction was complete, the mixed sol was poured into a polytetrafluoroethylene mold. After the ethanol evaporated, the ionic gel was obtained. The SEM image is shown below. Figure 1 As shown. After gelation, the [EMIM][ESO4] ionic liquid was soaked to obtain P(LA-LIM)-IL gel electrolyte.

[0040] The mechanical properties of the polymer can be adjusted by controlling the amount of LIM. When the LIM concentration is low (e.g., greater than the LA:LIM molar ratio of 20:1), the prepared P(LA-LIM)-IL fails to achieve the expected gel state. When the LIM content is too high (e.g., less than the LA:LIM molar ratio of 5:1), the excessively high crosslinking density restricts the migration of molecular chains, leading to a decrease in its fracture strain. However, when the LA:LIM molar ratio is 10:1, P(LA-LIM)-IL exhibits good mechanical properties, showing a maximum fracture stress of 35 kPa and a maximum fracture strain of 350%.

[0041] Example 2: Preparation of nitrogen-doped porous carbon (NC) materials

[0042] First, nano-zeolite imidazole acid framework-8 particles (nZIF-8) were synthesized. CTAB (100 mg), 2-MiM (28 g), and zinc acetate dihydrate (6 g) were dissolved separately in DI water (100 mL). 1 g of CTAB solution was mixed thoroughly with 5.1 g of 2-MiM solution, and then 5.3 g of zinc acetate dihydrate solution was added to obtain a homogeneous white emulsion. After standing for 2 h, the emulsion was centrifuged (10000 rpm, 10 min), and the supernatant was discarded. The emulsion was then treated sequentially with CTAB solution (0.2 mg / mL). -1 The solid product was washed with deionized water and dried at 80°C for 24 hours to obtain nZIF-8 white powder.

[0043] Subsequently, nZIF-8 powder and nanocellulose (1 wt.%, dispersed in DI water) were compounded to prepare a mixed gel with an nZIF-8 concentration of 0.25 wt.%. The mixed gel was then transferred to a self-made mold and placed on a copper block pre-cooled with liquid nitrogen for directional freezing (the liquid nitrogen surface must not be higher than the upper surface of the copper block). After freeze-drying, a white aerogel was obtained.

[0044] Finally, the aerogel was placed in a corundum boat and placed in the center of a tube furnace. After continuous nitrogen purging for 30 min, the furnace was cooled at 5°C for 1 minute. -1The temperature was increased to 900℃ at different rates, and carbonized in a nitrogen atmosphere for 3 hours. The solid product was washed repeatedly with 1M HCl solution and DI water until pH=7, and then dried overnight at 80℃ to obtain NC material.

[0045] Example 3: Fracture stress-strain test of P(LA-LIM)-IL gel electrolyte

[0046] At room temperature, fracture stress-strain curves were measured using gel electrolyte samples measuring 1 cm × 5 cm × 2 mm. An electronic universal testing machine (SANS, CMT2503) was used at 10 mm / min. -1 The tensile speed was tested until it broke.

[0047] Experimental results show that the tensile elongation of P(LA-LIM)-IL gel electrolyte can reach 350%.

[0048] Example 4: Self-healing test of P(LA-LIM)-IL gel electrolyte

[0049] A 1cm×3cm×2mm gel electrolyte sample was cut into two segments and spliced ​​together. It self-healed at room temperature. The hydrogel could be picked up with tweezers and was stretchable.

[0050] like Figure 6 The image shows a photograph of the P(LA-LIM)-IL gel electrolyte self-healing at room temperature. It heals within 30 seconds of being cut, demonstrating rapid self-healing capabilities.

[0051] Example 5: Fabrication of flexible supercapacitors NC / / P(LA-LIM)-IL / / NC(CPCSCs)

[0052] Electrode materials NC, acetylene black, and polyvinylidene fluoride (PVDF) were ground evenly in a mortar at a ratio of 8:1:1 (wt.%). A small amount of N-methylpyrrolidone (NMP) was added and stirred to form a slurry. This slurry was then coated onto a 1cm × 2cm hydrophilic conductive carbon cloth (active material loading ~4mg / cm²). -2 The electrolyte was dried at 60℃ for 12 hours to obtain the NC electrode. A 1cm×1.5cm×2mm P(LA-LIM)-IL gel electrolyte was placed between the two NC electrodes, so that the area of ​​the electrodes facing each other was 1×1.5cm. 2 They form a symmetrical sandwich flexible supercapacitor.

[0053] Example 6: Electrochemical Performance Testing of Flexible Supercapacitors

[0054] Cyclic voltammetry test: The assembled supercapacitor was subjected to cyclic voltammetry test on an electrochemical workstation. The voltage window was set to 0–1 V, and the scan rate was 10 mV s.-1 20mV s -1 30mV s -1 40mV s -1 50mV s -1 .

[0055] Constant current charge-discharge test: The supercapacitor is charged and discharged under a constant current of 0.3 mA / cm². -2 0.4mAcm -2 0.6mAcm -2 0.8mA cm -2 1.0mAcm -2 .

[0056] like Figure 2 As shown, under room temperature testing conditions, the CV and GCD of CPCSCs remain almost unchanged with the increase of scan rate or current density, indicating that CPCSCs have excellent rate capability and electrochemical reversibility.

[0057] To investigate the electrochemical performance of the flexible supercapacitor at different temperatures, charge-discharge tests were conducted on the supercapacitor under a constant current of 0.8 mA / cm². -2 The test temperatures were -10℃, room temperature (22℃), 30℃, 40℃, and 50℃. The results are as follows: Figure 3 As shown, the GCD of CPCSCs remains almost unchanged, and they can still operate normally at low temperatures. When the temperature rises back to room temperature, the supercapacitor can still recover 80% of its initial capacitance, indicating that CPCSCs still have excellent electrochemical performance at low and high temperatures and are suitable for a wide temperature range.

[0058] Example 7: Testing the flexibility and self-healing properties of flexible supercapacitors

[0059] The assembled supercapacitor was sequentially bent to 0°, 30°, 60°, 90°, 180° or twisted, and then subjected to cyclic voltammetry tests (scan rate 10 mV / s). -1 ) and constant current charge-discharge test (test current 1mAcm) -2 ).

[0060] Mechanical deformation cycle test: The device is bent sequentially to 0°, 30°, 90°, 180° or twisted, with each mechanical deformation cycle repeated 25 times before the next mechanical deformation. Simultaneously, a constant current charge-discharge test is performed (test current 4 mA / cm²). -2 ). Figure 4 The results showed that the CV curves of CPCSCs at different bending angles basically overlapped, and the GCD curves did not show obvious capacitance decay. After 100 mechanical deformations, they maintained more than 85% of their performance.

[0061] Cut the assembled component in half with scissors, let it stand for 30 seconds to self-heal, and then perform a GCD test (test current 0.8 mA / cm²). -2 ), to study the self-healing properties of the device. Figure 5 The results showed that after 20 cutting / healing cycles, the capacitor could still recover more than 92% of its original capacity.

[0062] The above embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention. Modifications and substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the present invention are all within the scope of the present invention.

Claims

1. A self-healing flexible supercapacitor based on dual dynamic bonds, characterized in that, The capacitor comprises a gel electrolyte and two symmetrical electrodes; the gel electrolyte is a P(LA-LIM)-IL ionic gel electrolyte, which is prepared by ring-opening polymerization and cross-linking of lipoic acid and limonene to form a three-dimensional porous network containing dynamic disulfide bonds and hydrogen bonds, and then introducing an ionic liquid; the electrodes contain nitrogen-doped porous carbon electrode active material, which is formed by carbonization of nano-zeolite imidazole acid framework-8 and nano-cellulose; the gel electrolyte and the two symmetrical electrodes form a sandwich structure with the gel electrolyte as the core through self-adhesion.

2. The self-healing flexible supercapacitor based on dual dynamic bonds according to claim 1, characterized in that, The nano-zeolite imidazole acid framework-8 was prepared by a self-assembly-co-crystallization reaction of hexadecyltrimethylammonium bromide, 2-methylimidazolium and a zinc-containing compound.

3. The self-healing flexible supercapacitor based on dual dynamic bonds according to claim 1, characterized in that, The zinc-containing compound is zinc acetate dihydrate.

4. The self-healing flexible supercapacitor based on dual dynamic bonds according to claim 1, characterized in that, The ionic liquid is ethyl 1-ethyl-3-methylimidazolium sulfate.

5. The method for preparing the self-healing flexible supercapacitor based on double dynamic bonds according to any one of claims 1-4, characterized in that, include: Step 1, Preparation of gel electrolyte: Dissolve lipoic acid in an organic solvent, then add ethyl 1-ethyl-3-methylimidazolium sulfate, stir until homogeneous, then slowly add limonene while continuing to stir until the solution viscosity increases. After the organic solvent evaporates, an ionic gel is obtained. After gelation, soak in an ionic liquid to obtain P(LA-LIM)-IL gel electrolyte; wherein the molar ratio of lipoic acid to limonene is 1:(0.005-0.2). Step 2, Preparation of symmetrical electrode: Nitrogen-doped porous carbon electrode active material, conductive agent and binder are mixed and coated on flexible current collector, and the electrode is obtained after drying; The preparation method of the nitrogen-doped porous carbon electrode active material includes: (1) mixing hexadecyltrimethylammonium bromide solution and 2-methylimidazole solution, then adding zinc-containing compound solution, letting stand, and then centrifuging to separate; (2) Wash the solid product and dry it to obtain nano zeolite imidazole acid framework-8; (3) Combine nano zeolite imidazole acid framework-8 with nano cellulose and then perform directional freeze-drying; (4) Carbonize it at 800-1000℃ under nitrogen atmosphere, wash and dry it to obtain nitrogen-doped porous carbon. Step 3, Assemble the capacitor: Sandwich the gel electrolyte between two symmetrical electrodes and press them together to form a sandwich structure, thus obtaining the self-healing flexible supercapacitor based on dual dynamic bonds.

6. The preparation method according to claim 5, characterized in that, The flexible current collector is a hydrophilic conductive carbon cloth.

7. The preparation method according to claim 5, characterized in that, The conductive agent is acetylene black, and the binder is polyvinylidene fluoride; in the electrode preparation raw materials, the mass ratio of nitrogen-doped porous carbon electrode active material: acetylene black: polyvinylidene fluoride is 8:1:

1.

8. The preparation method according to claim 5, characterized in that, The nitrogen-doped porous carbon electrode active material is loaded onto the flexible carbon cloth at a rate of approximately 4 mg / cm². -2 .

9. The preparation method according to claim 5, characterized in that, The preparation method includes: Step 1: Prepare P(LA-LIM)-IL gel electrolyte by dissolving 1–3 g of lipoic acid in 2–5 mL of anhydrous ethanol to obtain a yellow transparent solution, and then adding 0.25–0.75 mol L... -1 1-Ethyl-3-methylimidazolium sulfate ethyl ester, stirred for 3–5 min, then slowly added dropwise at 0.125–0.5 mol / L. -1 After stirring limonene for 2-5 minutes, the solution viscosity increases. The mixed sol is then poured into a polytetrafluoroethylene mold. After the ethanol evaporates, an ionic gel is obtained. After gelation, the ionic liquid is soaked in the gel to obtain P(LA-LIM)-IL gel electrolyte. Step 2: Preparation of active materials. Dissolve 100 mg of hexadecyltrimethylammonium bromide, 28 g of 2-methylimidazole, and 6 g of zinc acetate dihydrate in 100 mL of deionized water. Mix 1 g of hexadecyltrimethylammonium bromide solution with 5.1 g of 2-methylimidazole solution, then add 5.3 g of zinc acetate dihydrate solution to obtain a white, homogeneous emulsion. After standing for 1.5–2.5 h, centrifuge at 9000–11000 rpm for 5–15 min, discard the supernatant, wash the solid product, and dry at 80 °C for 12–24 h to obtain a white powder of nano-zeolite imidazolium acid framework-8. Combine nano-zeolite imidazolium acid framework-8 with 1 wt.% nanocellulose to form a mixed gel with a nano-zeolite imidazolium acid framework-8 concentration of 0.2–0.3 wt.%. After directional freeze-drying and lyophilization, reflux at 3–10 °C under a nitrogen atmosphere. -1 The temperature was increased to 800-1000℃ and carbonized for 2.5-3.5 hours. After washing and drying, nitrogen-doped porous carbon electrode active material was obtained. Step 3: Weigh the nitrogen-doped porous carbon, acetylene black and polyvinylidene fluoride obtained in Step 2 in a mass ratio of 8:1:1, grind them evenly in a mortar, add a small amount of N-methylpyrrolidone, stir into a slurry, coat it onto hydrophilic conductive carbon cloth, and dry it at 60°C for 12-24 hours; sandwich the gel electrolyte from Step 1 between the two electrodes and press them together to form a sandwich structure, thus obtaining a self-healing flexible supercapacitor.

10. The preparation method according to claim 5, characterized in that, Use 0.2 mg mL -1 The solid product was washed with hexadecyltrimethylammonium bromide and deionized water, and dried to obtain nano-zeolite imidazolium acid framework-8 white powder; the carbonized solid product was washed multiple times with 1M HCl solution and DI water until pH=7, and then dried to obtain nitrogen-doped porous carbon electrode active material.

Images