Self-repairing flexible supercapacitor and preparation method thereof

Abstract

The invention discloses a self-repairing flexible supercapacitor and a preparation method thereof, and belongs to the technical field of flexible energy storage devices. According to the capacitor, an HAZCN HOF electrode and PDA-PAM self-repairing hydrogel are seamlessly integrated to form an integrated structure, and efficient self-repairing is achieved through hydrogen bonds between the HAZCN HOF and the PDA-PAM hydrogel and the dynamic effect of pi-pi accumulation. According to the HAZCN HOF electrode, a three-dimensional frame structure containing rich hydrogen bonds and redox active sites is formed through dehydration condensation and self-assembly of cyclohexanehexone and 4, 5-diamino phthalonitrile. The PDA-PAM hydrogel electrolyte is copolymerized with acrylamide through dopamine to form an interpenetrating network containing catechol groups, intermolecular hydrogen bonds and pi-pi accumulation. The integrated flexible supercapacitor has high energy storage performance and excellent self-repairing characteristic, and has important application value in the field of wearable electronics.

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 high pseudocapacitance and self-healing hydrogel electrolyte and its fabrication method, which is suitable for wearable electronics, implantable medical devices and other scenarios with strict requirements for flexibility, self-healing and high energy storage performance. Background Technology

[0002] As wearable electronic devices rapidly evolve towards lightweight, flexible, and multifunctional designs, stringent requirements are placed on the flexibility, deformation resistance, and lifespan of energy storage devices. Supercapacitors, with their high power density, excellent safety, and ultra-long cycle life, have become core candidate devices in the field of flexible energy storage. However, traditional flexible supercapacitors face three major challenges: First, the interface contact problem is prominent. In the traditional "electrolyte-electrode" sandwich structure, the interfacial interaction between the electrode and the electrolyte is weak, resulting in persistently high contact resistance, significantly limiting charge transfer efficiency. Simultaneously, this structure is prone to delamination and misalignment under bending, twisting, and folding deformation conditions, further exacerbating the degradation of electrochemical performance. Second, the performance of electrode materials is limited. Existing integrated flexible supercapacitor designs largely rely on the in-situ polymerization of conductive polymers (such as polyaniline and polypyrrole) on the electrolyte. These materials not only have a narrow selection range but also inherent defects such as poor cycle stability, high rigidity, and low pseudocapacitance, making it difficult to meet high energy storage demands. Third, mechanical damage repair is difficult. Flexible devices inevitably endure repeated external forces during long-term use, which can easily lead to structural damage such as cracks, fractures, and peeling. Traditional devices lack effective self-repair mechanisms, resulting in a significantly shortened lifespan or even direct failure.

[0003] Therefore, developing an integrated flexible supercapacitor with strong interface bonding, high pseudocapacitance, and efficient self-healing function has become a breakthrough direction. Summary of the Invention

[0004] This invention aims to overcome the key defects of existing flexible supercapacitors in practical applications, including: high interface contact resistance leading to low charge transport efficiency, insufficient pseudocapacitance of electrode materials limiting energy storage performance, poor self-healing performance leading to performance degradation after multiple repairs, and complex manufacturing process that relies on additional adhesives, increasing costs.

[0005] This invention constructs an integrated device based on a HAZCN HOF electrode and a self-healing PDA-PAM hydrogel electrolyte through a seamless interface integration design. By integrating the high pseudocapacitive HAZCN HOF electrode with the highly efficient self-healing PDA-PAM hydrogel electrolyte, the hydrogen bond network of HAZCN HOF and the self-adhesive groups of the PDA-PAM hydrogel electrolyte form a strong interfacial interaction, significantly reducing interfacial resistance and improving mechanical tolerance during deformation. Simultaneously, the redox active groups in the HOF electrode provide high pseudocapacitance, and its hydrogen bond framework ensures structural integrity during repeated charge-discharge cycles and cutting / healing processes. The synergistic effect of these two components is expected to simultaneously achieve excellent electrochemical performance, superior flexibility, and highly efficient self-healing capabilities, solving a long-standing technical bottleneck in traditional flexible supercapacitors. The electrode and electrolyte achieve seamless bonding through hydrogen bonds and π-π stacking interactions, forming an integrated structure without interfacial gaps, and relying on dynamic interactions to achieve self-healing functionality.

[0006] This invention achieves the above objectives through the following key technologies:

[0007] A self-healing flexible supercapacitor includes a high pseudocapacitive electrode and a self-healing hydrogel electrolyte. The high pseudocapacitive electrode comprises HAZCN HOF electrode active material, which forms a three-dimensional framework structure rich in hydrogen bonds and redox active sites through dehydration condensation and self-assembly of cyclohexanehexanone and 4,5-diaminophthalonitrile. The electrolyte is a PDM-PAM hydrogel electrolyte obtained by solute replacement of PDA-PAM hydrogel. The PDM-PAM hydrogel is formed by copolymerization of dopamine and acrylamide to form an interpenetrating network hydrogel containing catechol groups, intermolecular hydrogen bonds, and π-π stacking interactions. The high pseudocapacitive electrode and the electrolyte achieve seamless bonding through hydrogen bonds and π-π stacking interactions, forming an integrated structure without interfacial gaps.

[0008] Preferably, the solute is a sulfuric acid solution.

[0009] The present invention also provides a method for preparing the self-healing flexible supercapacitor, comprising:

[0010] Step 1, Preparation of HAZCN HOF electrode active material: Cyclohexanehexanone and 4,5-diaminophthalonitrile (AP) are dehydrated and condensed in a mixed solvent of acetic acid / methanol to generate a three-dimensional framework containing dynamic hydrogen bonds;

[0011] Step 2, Preparation of PDA-PAM hydrogel electrolyte: Dopamine and acrylamide form an interpenetrating network PDM-PAM hydrogel through free radical polymerization. The hydrogel is then subjected to solute placement to obtain PDM-PAM hydrogel electrolyte.

[0012] Step 3, Assemble the capacitor: Prepare a flexible positive electrode; Add conductive agent and binder to the HAZCN HOF electrode active material obtained in Step 1 and coat it onto the flexible current collector. After drying, a high pseudocapacitive electrode is obtained as the negative electrode; The electrolyte described in Step 2 is sandwiched between the positive and negative electrodes and pressed together to form an integrated structure, thus obtaining the self-healing flexible supercapacitor.

[0013] Preferably, the positive electrode uses activated carbon as the active material, and the activated carbon is attached to the flexible current collector. More preferably, the positive electrode is prepared by coating activated carbon, a conductive agent, and a binder onto the flexible current collector, and then drying to obtain a flexible positive electrode.

[0014] Preferably, the flexible current collector is a hydrophilic conductive carbon cloth.

[0015] Preferably, the conductive agent is acetylene black, and the binder is polyvinylidene fluoride.

[0016] According to a specific embodiment of the present invention, in the raw materials for preparing the negative electrode, the mass ratio of HAZCN HOF electrode active material: acetylene black: polyvinylidene fluoride is 6:3:1.

[0017] According to a specific embodiment of the present invention, in the raw materials for preparing the positive electrode, the mass ratio of activated carbon: acetylene black: polyvinylidene fluoride is 8:1:1.

[0018] In step 1, the cyclohexanehexaone structure provides abundant carbonyl groups, and the phthalonitrile group of AP introduces a cyano group. The two form an imine bond through dehydration condensation, while releasing water molecules to promote framework self-assembly.

[0019] In step 2, the catechol groups of dopamine provide self-adhesion, and the intermolecular hydrogen bonds of acrylamide enhance mechanical strength.

[0020] Preferably, in step 2, N,N'-methylenebisacrylamide is introduced as a crosslinking agent to form a three-dimensional network containing dynamic hydrogen bonds and π-π stacking.

[0021] Preferably, the active material loading of the high pseudocapacitive electrode is 1 mg cm⁻¹. -2 .

[0022] Preferably, the positive electrode activated carbon loading is ~2 mg / cm³. -2 .

[0023] Specifically, a method for fabricating a seamlessly integrated self-healing flexible supercapacitor includes:

[0024] Step 1, Preparation of HAZCN HOF electrode active material: 61 mg of cyclohexanehexaone octahydrate and 96 mg of 4,5-diaminophthalonitrile were added to a mixed solvent of 5 mL methanol and 7 mL acetic acid. The mixture was stirred at 100 °C for 48 h under a nitrogen atmosphere to complete the dehydration condensation to generate HAT-CN monomer. After the reaction, the product was washed three times with ethanol and dried under vacuum at 80 °C to obtain HAZCN monomer. 40 mg of HAT-CN monomer was dissolved in a mixed solvent of 9 mL chloroform and 3 mL methanol. The solvent was slowly evaporated at room temperature, and HAZCN HOF electrode active material with a three-dimensional structure containing abundant redox active sites was formed through intermolecular hydrogen bonding self-assembly.

[0025] Step 2, Preparation of PDA-PAM hydrogel electrolyte: Dopamine hydrochloride was dissolved in an aqueous solution containing sodium hydroxide (pH adjusted to 11), and stirred for 20 min in an air atmosphere to form polydopamine chains through alkali-induced prepolymerization; under ice bath conditions, the above polydopamine chain dispersion was mixed with acrylamide, ammonium persulfate, N,N'-methylenebisacrylamide, and tetramethylethylenediamine and stirred for 10 min, then the ice bath and stirrer were removed to allow acrylamide to polymerize and polydopamine to be further induced to polymerize by ammonium persulfate to form PDA-PAM interpenetrating network hydrogel; the hydrogel was immersed in 1M sulfuric acid solution for 2 h for solute replacement, and finally PDA-PAM hydrogel electrolyte with both high ionic conductivity and self-healing properties was obtained;

[0026] Step 3, Assemble the capacitor: Weigh the HAZCN HOF electrode active material, acetylene black, and polyvinylidene fluoride obtained in Step 1 in a mass ratio of 6:3:1, grind them evenly in a mortar, add a small amount of N-methylpyrrolidone to make a slurry, coat it onto a hydrophilic conductive carbon cloth, and dry it at 60℃ for 6 hours to obtain a high pseudocapacitive electrode, which serves as the negative electrode of the device; Weigh the activated carbon, acetylene black, and polyvinylidene fluoride in a mass ratio of 8:1:1, grind them evenly in a mortar, add a small amount of N-methylpyrrolidone to make a slurry, coat it onto a hydrophilic conductive carbon cloth, and dry it at 60℃ for 6 hours to obtain the positive electrode of the device; Cut the electrolyte from Step 2 into a 1 mm thick sheet, sandwich it between the two electrodes, and press it together to form an integrated structure without interface gaps, thus obtaining a seamless integrated self-healing flexible supercapacitor.

[0027] According to a specific embodiment of the present invention, the gel electrolyte prepared in step 1 has a size of 1cm × 2cm × 1mm. Then, the positive and negative electrodes prepared in step 3 are attached to the upper and lower end faces of the hydrogel electrolyte, so that the facing area of ​​the two electrodes is 1 × 2cm. 2 The dimensions of the "three-layer structure" supercapacitor assembled in step 3 are for testing purposes; in practical applications, the dimensions can be arbitrary. The hydrophilic conductive carbon cloth can be 1cm × 3cm in size to meet the aforementioned facing area dimensions.

[0028] According to a specific embodiment of the present invention, the active material loading of the high pseudocapacitive electrode prepared in step 1 is 1 mg / cm³. -2 The active material loading of the positive electrode is 2 mg cm⁻¹ -2 .

[0029] The core of this invention is the efficient fabrication of a high pseudocapacitive self-healing flexible supercapacitor through a process of "HAZCN HOF electrode—PDA-PAM hydrogel electrolyte—seamless integrated assembly." First, a high pseudocapacitive HOF electrode is constructed through dehydration condensation-self-assembly: using cyclohexanehexanone and 4,5-diaminophthalonitrile as raw materials, dehydration condensation forms the HAT-CN monomer, followed by room-temperature solvent evaporation-induced self-assembly, forming a three-dimensional HOF structure rich in hydrogen bonds and redox active sites, providing a foundation for rapid ion transport and high pseudocapacitance. Second, a PDA-PAM hydrogel electrolyte is constructed through base-induced prepolymerization-free radical copolymerization. The catechol groups of PDA provide self-adhesion, while the intermolecular hydrogen bonds of the PAM chains and the π-π stacking of the PDA aromatic rings form a dual dynamic effect, endowing the hydrogel with excellent tensile and self-healing properties, further improving interfacial compatibility. Furthermore, the interfacial bonding is enhanced through the synergistic effect of dual dynamic bonds: hydrogen bonds are formed between HAZCN HOF and the PDA-PAM hydrogel electrolyte, while the aromatic rings of HOF and the benzene rings of PDA undergo π-π stacking, achieving seamless bonding between the electrode and electrolyte and forming an integrated structure without interfacial gaps. This eliminates the need for additional adhesives, suppressing delamination and charge transport losses during deformation. Finally, relying on the self-adhesion of the PDA-PAM hydrogel electrolyte, a tight bond can be achieved between the HAZCN HOF electrode and the gel electrolyte in the device. Ultimately, the device maintains high pseudocapacitance while also exhibiting excellent flexibility and self-healing properties.

[0030] Beneficial effects

[0031] (1) The HAZCN HOF electrode prepared in this invention exhibits excellent synergistic performance with the PDA-PAM hydrogel electrolyte, including high pseudocapacitance, efficient self-healing, and strong interfacial bonding. The HAZCN HOF electrode at 0.5 Ag... -1 The specific capacitance can reach 821F g -1 Furthermore, the capacitance shows no decay after 50,000 cycles, thanks to the structural stability provided by abundant redox active sites and a hydrogen bond network. The PDA-PAM hydrogel electrolyte exhibits excellent stretch ratio, enabling flexible operations such as bending and stretching, and it can self-repair quickly after cutting. The two components are tightly bound together through hydrogen bonds, resulting in low interfacial resistance, effectively suppressing delamination during deformation and ensuring efficient charge transport.

[0032] (2) The device of the present invention has excellent flexibility and structural stability. The hydrogen bonds and π-π stacking in the PDA-PAM hydrogel electrolyte give it good mechanical resistance. After the device is subjected to mechanical changes such as deformation and torsion at various angles, the capacitance can still maintain 80.1% of the initial capacitance value, which can adapt to the complex use environment of wearable devices.

[0033] (3) The integrated flexible supercapacitor assembled in this invention exhibits excellent electrochemical performance and self-healing cycle stability. The device operates at 2 mA cm⁻¹. -2 The specific capacitance of the lower area reaches 576 mF cm. -2 Energy density 135 μWh cm⁻¹ -2 (Power density 1300 μW cm⁻¹) -2 It outperforms most existing flexible supercapacitors; after 25 cutting / healing cycles, the capacitance does not decrease, which is attributed to the efficient interface repair and structural reconstruction achieved by hydrogen bonding and π-π stacking dynamics.

[0034] (4) The raw materials used in this invention are readily available and the preparation process is simple and efficient. HAZCN HOF is synthesized by one-pot dehydration condensation-self-assembly, and PDA-PAM hydrogel is prepared by one-step free radical polymerization. During the assembly, the gel is formed by self-adhesive compression without the need for 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

[0035] Figure 1 The constant current charge-discharge curves of HAZCN HOF in Example 1 are shown at different current densities.

[0036] Figure 2 The cycling performance of the HAZCN HOF electrode in Example 1 is shown.

[0037] Figure 3 Scanning electron microscope image of the PDA-PAM hydrogel electrolyte prepared in Example 2.

[0038] Figure 4 Optical microscope image of the PDA-PAM hydrogel electrolyte cutting-healing process prepared in Example 2.

[0039] Figure 5 Electrochemical test results of the supercapacitor prepared in Example 4: (a) cyclic voltammetry curves at different scan rates and (b) constant current charge-discharge curves at different current densities.

[0040] Figure 6 The interfacial peel strength of HAZCN HOF and PDA-PAM hydrogels prepared in Examples 1 and 2.

[0041] Figure 7The results of the flexibility test for the supercapacitor prepared in Example 4 are shown.

[0042] Figure 8 The self-healing performance of the supercapacitor prepared in Example 4.

[0043] Figure 9 Photos showing the supercapacitor prepared in Example 4 before and after self-healing, with a small light bulb lit. Detailed Implementation

[0044] Example 1: Preparation of HAZCN HOF material

[0045] Weigh 61 mg of cyclohexanehexaone octahydrate and 96 mg of 4,5-diaminophthalonitrile (AP), and add them to a mixed solvent of 5 mL methanol and 7 mL acetic acid. Under a nitrogen atmosphere, stir the mixture at 100 °C for 48 h. After the reaction is complete, wash the product three times with ethanol and dry it under vacuum at 80 °C to obtain the HAT-CN monomer.

[0046] Take 40 mg of HAT-CN monomer and dissolve it in a mixed solvent of 9 mL of chloroform and 3 mL of methanol; slowly evaporate the solvent at room temperature to obtain HAZCN HOF electrode active material.

[0047] Example 2: Preparation of PDA-PAM hydrogel electrolyte

[0048] First, polydopamine (PDA) is prepolymerized: dopamine hydrochloride is dissolved in an aqueous solution containing sodium hydroxide (pH adjusted to 11), and stirred for 20 minutes in an air atmosphere to form polydopamine chains through alkali-induced prepolymerization.

[0049] Subsequently, a copolymerization reaction of dopamine and acrylamide was carried out: under ice bath conditions, the above polydopamine chain dispersion was mixed with acrylamide, ammonium persulfate, N,N'-methylenebisacrylamide, and tetramethylethylenediamine and stirred; after 10 min, the ice bath and stirrer were removed, allowing acrylamide to polymerize and polydopamine to be further induced to polymerize by ammonium persulfate, forming PDA-PAM hydrogel.

[0050] Finally, solute exchange was performed: the hydrogel was immersed in 1M sulfuric acid solution for 2 hours to complete the solute exchange, yielding the PDA-PAM hydrogel electrolyte, the SEM image of which is shown below. Figure 3 As shown.

[0051] Example 3: Performance Testing of PDA-PAM Hydrogel Electrolyte

[0052] The hydrogel electrolyte was cut into 1cm × 5cm × 1mm samples and tested using a universal tensile testing machine (SANS, CMT2503) at a speed of 10mm min. -1The material was stretched at a certain rate until it broke, and the stretch ratio was measured to be 405%.

[0053] The hydrogel electrolyte was cut into strips of 1cm × 3cm × 1mm. After cutting with a blade, the cut surfaces were aligned and left to stand at room temperature for a period of time. Optical microscopy showed that the cut surfaces were completely healed (see reference). Figure 4 ).

[0054] Example 4: Assembly of an integrated flexible supercapacitor

[0055] HAZCN HOF powder, acetylene black, and polyvinylidene fluoride were mixed in a mass ratio of 6:3:1, and a small amount of N-methylpyrrolidone was added. The mixture was then ground into a uniform slurry. The slurry was coated onto a 1cm × 3cm hydrophilic carbon cloth, with the active material loading controlled at ~1mg / cm². -2 The HAZCN HOF electrode (negative electrode) was obtained by vacuum drying at 60-80℃ for 6 hours. The obtained HAZCN HOF electrode was then subjected to constant current charge-discharge testing on a CHI760E electrochemical workstation (three-electrode conditions: HAZCN HOF electrode as working electrode, Hg / Hg2SO4 as reference electrode, and Pt electrode as counter electrode; test currents were 0.5, 1, 3, 5, 7, 9, and 10 Ag). -1 The voltage window is set to -0.7 to 0V. The HAZCN HOF electrode is at 0.5Ag. -1 The specific capacitance can reach 821F g -1 ( Figure 1 As shown), in 10Ag -1 The specific capacitance can also reach 500F g -1 And the capacitance does not decay after 50,000 cycles. Figure 2 (As shown), this is due to the structural stability imparted by the abundant redox active sites and hydrogen bond network of the HAZCN HOF electrode active material.

[0056] Activated carbon, acetylene black, and polyvinylidene fluoride were ground evenly in a mortar at a ratio of 8:1:1 (wt.%). A small amount of N-methylpyrrolidone was added and stirred into a slurry. This slurry was then coated onto a 1cm × 3cm hydrophilic conductive carbon cloth (active material loading ~2mg / cm²). -2 The cathode was obtained by drying at 60℃ for 6 hours.

[0057] Ensure that the dimensions of the two electrodes are matched. Cut the PDA-PAM hydrogel electrolyte into a 1cm×2cm×1mm sheet and sandwich it between the two electrodes to form a sandwich structure; seal the edges of the device with tape, leaving the carbon cloth end exposed as a lead, to obtain the HAZCN HOF / / PDA-PAM / / AC flexible supercapacitor.

[0058] Example 5: Electrochemical Performance Testing of Flexible Supercapacitors

[0059] Cyclic voltammetry test: The assembled supercapacitor was subjected to cyclic voltammetry testing on a CHI760E electrochemical workstation. The voltage window was set to 0–1.3 V, and the scan rate was set to 10 mV / s. -1 —50mV s -1 .

[0060] Constant current charge-discharge test: The supercapacitor is charged and discharged under a constant current of 2 mA / cm². -2 —10mAcm -2 .

[0061] Test results are available Figure 5 As shown. The supercapacitor operates at 2mA cm⁻¹. -2 The specific capacitance of the lower area reaches 576 mF cm. -2 Energy density 135 μWh cm⁻¹ -2 (Power density 1300 μW cm⁻¹) -2 It is superior to most existing flexible supercapacitors.

[0062] Example 6: Interface peeling performance test of flexible supercapacitor

[0063] The assembled supercapacitor was subjected to a 180° peel test using a universal testing machine, with a minimum peel thickness of 5 mm. -1 The peeling speed was measured, and the higher the peeling force, the tighter the interfacial bonding, i.e., the stronger the interfacial bonding force. Experimental results showed that the HAZCN HOF-hydrogel interface exhibited a gradual breakdown mode during peeling, with a maximum peeling force of 1.6 N, which was superior to the interfacial force of traditional hydrogel electrolyte / traditional activated carbon electrode. Figure 6 ).

[0064] This invention enhances interfacial bonding through the synergistic effect of dual dynamic bonds: hydrogen bonds are formed between HAZCN HOF and PDA-PAM hydrogel electrolyte, while the aromatic rings of HOF and the benzene rings of PDA generate π-π stacking, achieving seamless bonding between the electrode and electrolyte, and suppressing delamination and charge transport loss during deformation without the need for additional adhesives.

[0065] Example 7: Flexibility Testing of Flexible Supercapacitors

[0066] Through bending tests, the assembled supercapacitor was bent to 0°, 30°, 90°, 180°, or twisted, and subjected to 24 constant current charge-discharge tests (test current 10mA cm⁻¹) while maintaining several bending / twisting states. -2 A total of 120 tests were conducted. Figure 7The results show that the capacitor retains 80.1% or more of its initial capacitance value after 120 bending and twisting cycles, and the capacitance decay rate is less than 10% under small-angle bending, demonstrating its excellent flexibility.

[0067] Example 8: Self-healing performance test of flexible supercapacitor

[0068] The assembled supercapacitor was subjected to constant current charge-discharge testing using a CHI760E electrochemical workstation. The test current was 10 mA cm⁻¹. -2 The supercapacitor was cut in half and subjected to contact repair for 3 minutes. After repair, a constant current charge-discharge test was performed under the same conditions to obtain the specific capacitance after one cutting / healing cycle. The supercapacitor could be subjected to constant current charge-discharge tests after 25 cutting / healing cycles. After 25 cutting / healing cycles, the capacitance showed no decay (see...). Figure 8 This is attributed to the efficient interface repair and structural reconstruction achieved through hydrogen bonding and π-π stacking dynamics. Four assembled supercapacitors were connected in series, and then a 3.6V light bulb was connected to them. The light bulb's illumination was observed. One of the supercapacitors in the series was cut off, and the cut surface was brought back into contact with the light bulb for 3 minutes before being reconnected. The light bulb's illumination was then observed. Figure 9 (Photo of the light bulb lit up) This visually demonstrates that the repaired device successfully drives the light bulb to light up, proving its functional integrity.

[0069] 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, characterized in that, The device includes a high pseudocapacitive electrode and a self-healing hydrogel electrolyte. The high pseudocapacitive electrode comprises HAZCN HOF electrode active material, which forms a three-dimensional framework structure rich in hydrogen bonds and redox active sites through dehydration condensation and self-assembly of cyclohexanehexanone and 4,5-diaminophthalonitrile. The electrolyte is a PDM-PAM hydrogel electrolyte obtained by solute replacement of PDA-PAM hydrogel. The PDM-PAM hydrogel is formed by copolymerization of dopamine and acrylamide to form an interpenetrating network hydrogel containing catechol groups, intermolecular hydrogen bonds, and π-π stacking interactions. The high pseudocapacitive electrode and the electrolyte are seamlessly bonded together through hydrogen bonds and π-π stacking interactions, forming an integrated structure without interfacial gaps.

2. The self-healing flexible supercapacitor according to claim 1, characterized in that, The solute is a sulfuric acid solution.

3. The method for preparing the self-healing flexible supercapacitor according to claim 1 or 2, characterized in that, include: Step 1, Preparation of HAZCN HOF electrode active material: Cyclohexanehexanone and 4,5-diaminophthalonitrile (AP) are dehydrated and condensed in a mixed solvent of acetic acid / methanol to generate a three-dimensional framework containing dynamic hydrogen bonds; Step 2, Preparation of PDA-PAM hydrogel electrolyte: Dopamine and acrylamide form an interpenetrating network PDM-PAM hydrogel through free radical polymerization. The hydrogel is then subjected to solute placement to obtain PDM-PAM hydrogel electrolyte. Step 3, Assemble the capacitor: Prepare a flexible positive electrode; Add conductive agent and binder to the HAZCN HOF electrode active material obtained in Step 1 and coat it onto the flexible current collector. After drying, a high pseudocapacitive electrode is obtained as the negative electrode; The electrolyte described in Step 2 is sandwiched between the positive and negative electrodes and pressed together to form an integrated structure, thus obtaining the self-healing flexible supercapacitor.

4. The preparation method according to claim 3, characterized in that, The positive electrode uses activated carbon as the active material, and the activated carbon is attached to the flexible current collector.

5. The preparation method according to claim 3 or 4, characterized in that, The flexible current collector is a hydrophilic conductive carbon cloth.

6. The preparation method according to claim 4, characterized in that, The positive electrode is prepared by coating activated carbon, a conductive agent, and a binder onto a flexible current collector and drying it to obtain a flexible positive electrode. The conductive agent is acetylene black, and the binder is polyvinylidene fluoride. In the raw materials for preparing the negative electrode, the mass ratio of HAZCN HOF electrode active material: acetylene black: polyvinylidene fluoride is 6:3:

1. In the raw materials for preparing the positive electrode, the mass ratio of activated carbon: acetylene black: polyvinylidene fluoride is 8:1:

1.

7. The preparation method according to claim 3, characterized in that, In step 2, N,N'-methylenebisacrylamide is introduced as a crosslinking agent.

8. The preparation method according to claim 3, characterized in that, The active material loading of the high pseudocapacitive electrode is 1 mg cm⁻¹. -2 .

9. The preparation method according to claim 4, characterized in that, The positive electrode activated carbon loading is 2 mg / cm³. -2 .

10. The preparation method according to claim 3, characterized in that, include: Step 1, Preparation of HAZCN HOF electrode active material: 61 mg of cyclohexanehexaone octahydrate and 96 mg of 4,5-diaminophthalonitrile were added to a mixed solvent of 5 mL methanol and 7 mL acetic acid. The mixture was stirred at 100 °C for 48 h under a nitrogen atmosphere to complete the dehydration condensation to generate HAT-CN monomer. After the reaction, the product was washed three times with ethanol and dried under vacuum at 80 °C to obtain HAZCN monomer. 40 mg of HAT-CN monomer was dissolved in a mixed solvent of 9 mL chloroform and 3 mL methanol. The solvent was slowly evaporated at room temperature, and HAZCN HOF electrode active material with a three-dimensional structure containing abundant redox active sites was formed through intermolecular hydrogen bonding self-assembly. Step 2, Preparation of PDA-PAM hydrogel electrolyte: Dopamine hydrochloride was dissolved in an aqueous solution containing sodium hydroxide, the pH was adjusted to 11, and the mixture was stirred in air for 20 min to form polydopamine chains through alkali-induced prepolymerization; under ice bath conditions, the above polydopamine chain dispersion was mixed with acrylamide, ammonium persulfate, N,N'-methylenebisacrylamide, and tetramethylethylenediamine and stirred for 10 min, and then the ice bath and stirrer were removed to allow acrylamide to polymerize and polydopamine to be further induced to polymerize by ammonium persulfate to form PDA-PAM interpenetrating network hydrogel; the hydrogel was immersed in 1M sulfuric acid solution for 2 h for solute replacement, and finally PDA-PAM hydrogel electrolyte with both high ionic conductivity and self-healing properties was obtained; Step 3, Assemble the capacitor: Weigh the HAZCN HOF electrode active material, acetylene black, and polyvinylidene fluoride obtained in Step 1 in a mass ratio of 6:3:1, grind them evenly in a mortar, add a small amount of N-methylpyrrolidone to make a slurry, coat it onto a hydrophilic conductive carbon cloth, and dry it at 60℃ for 6 hours to obtain a high pseudocapacitive electrode, which serves as the negative electrode of the device; Weigh the activated carbon, acetylene black, and polyvinylidene fluoride in a mass ratio of 8:1:1, grind them evenly in a mortar, add a small amount of N-methylpyrrolidone to make a slurry, coat it onto a hydrophilic conductive carbon cloth, and dry it at 60℃ for 6 hours to obtain the positive electrode of the device; Cut the electrolyte from Step 2 into a 1 mm thick sheet, sandwich it between the two electrodes, and press it together to form an integrated structure without interface gaps, thus obtaining a seamless integrated self-healing flexible supercapacitor.

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