Electrode material, preparation method thereof and application of electrode material in supercapacitor

Abstract

The invention relates to the technical field of flexible wearable devices, in particular to an electrode material, a preparation method of the electrode material and application of the electrode material in a supercapacitor. The preparation method of the electrode material comprises the following steps: dispersing a salt containing Ni < 2 + >, a salt containing Co < 2 + >, a ligand and MXene in an organic solvent, and anchoring metal ions Ni < 2 + > and Co < 2 + > with functional groups on the surface of the MXene to obtain a dispersion liquid; the dispersion liquid is subjected to a reaction, and the electrode material Ni / Co-MOF (at) MXene is obtained. Through the design of the bimetallic Ni / Co-MOF (at) MXene composite electrode material, the optimization of the gel solid electrolyte and the integrated packaging process, high specific capacitance, high power density and excellent mechanical stability of the flexible energy storage device are realized.

Description

Technical Field

[0001] This invention relates to the field of flexible wearable technology, specifically to an electrode material, its preparation method, and its application in supercapacitors. Background Technology

[0002] With the rapid development of smart wearable devices, flexible displays, electronic skin, and mobile healthcare, energy supply devices are facing comprehensive challenges in terms of lightweighting, flexibility, safety, and long lifespan. While traditional lithium-ion batteries offer high energy density, they are prone to electrode pulverization, electrolyte leakage, or short circuits when bent, stretched, or rolled, making it difficult to meet the safety and deformation compatibility requirements of flexible electronic devices. Therefore, all-solid-state flexible supercapacitors (ASFSCs), as energy storage devices with high power density, rapid charge / discharge capabilities, and excellent cycle life, have become an important development direction for next-generation wearable energy technology.

[0003] Currently, research on all-solid-state flexible supercapacitors mainly focuses on three aspects: electrode material design, electrolyte optimization, and device packaging structure improvement. Regarding electrode materials, carbon-based flexible carriers such as carbon cloth, carbon nanotube paper, and graphene films possess good conductivity and mechanical flexibility, but their specific capacitance is relatively low due to the lack of pseudocapacitive reaction sites. While transition metal oxides / hydroxides exhibit high electrochemical activity, they are brittle and have poor cycle stability, making it difficult to maintain structural integrity under repeated bending. In recent years, metal-organic frameworks (MOFs) have been introduced into flexible electrode systems due to their tunable pore structure, high specific surface area, and controllable metal centers. However, single-metal MOFs have poor conductivity and weak interfacial bonding, making them unsuitable for directly constructing flexible electrodes.

[0004] To improve charge transport and structural stability, existing technologies have proposed strategies for MOF-MXene composite structures. MXene (such as Ti3C2T) xMOFs possess high conductivity and abundant surface functional groups, making them ideal electrode substrates. The combination of MOFs and MXenes simultaneously achieves both high conductivity and porous structure, effectively improving ion transport efficiency and active site utilization. However, existing MOF@MXene preparation methods are mostly multi-step or post-loading methods, resulting in complex processes, weak interfacial bonding, and a focus on single-metal systems. Furthermore, the device assembly and packaging of flexible supercapacitors remain key bottlenecks restricting their performance improvement and practical application. Currently common gel electrolytes (such as PVA / H2SO4) suffer from low ion mobility and poor mechanical compatibility; simultaneously, interfacial mismatch and insufficient adhesion often exist between electrodes, electrolytes, and separators in the device's stacked structure, leading to increased internal resistance and capacity decay during bending or repeated cycling. Therefore, there is an urgent need for a simple, highly interfacially bonded, flexible, stable, and scalable all-solid-state flexible supercapacitor preparation method. In view of this, this invention provides an electrode material, its preparation method, and its application in supercapacitors. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide an electrode material, its preparation method, and its application in supercapacitors. The aim is to achieve high specific capacitance, high power density, and excellent mechanical stability in flexible energy storage devices through the design of bimetallic Ni / Co-MOF@MXene composite electrode materials, optimization of gel solid electrolytes, and integrated encapsulation processes. These devices are characterized by simple structure and scalable fabrication.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, a method for preparing an electrode material includes the following steps: [The text abruptly shifts to a seemingly unrelated topic about Ni and a method for preparing an electrode material.] 2+ Salt containing Co 2+ Salts, ligands and MXene (Ti3C2T) x Dispersed in an organic solvent, allowing metal ions Ni 2+ Co 2+ Anchored to the functional groups on the surface of MXene to obtain a dispersion; react the dispersion to obtain the electrode material Ni / Co-MOF@MXene.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the Ni-containing 2+ The salt and the Co-containing 2+ Ni in salt 2+ With Co 2+ The molar ratio is 1~2:1~2; Ni in the dispersion 2+The ratio of the amount of organic solvent used to that used organic solvent is (1~2) mmol: (15-30) mL; Ni in the dispersion 2+ The ratio of the ligand to the MXene is (1~2) mmol: (8~16) mmol: (10~20) mg.

[0009] Furthermore, the Ni-containing 2+ The salts include at least one of Ni(NO3)2 and Ni(CH3COO)2; The containing Co 2+ The salts include at least one of Co(NO3)2 and Co(CH3COO)2; The ligand is BTC (1,3,5-benzenetricarboxylic acid). The organic solvent includes DMF (N,N-dimethylformamide).

[0010] Furthermore, the reaction conditions for the dispersion are: temperature of 105~130℃ and time of 15 h~24 h.

[0011] Secondly, an electrode material, said electrode material being prepared by the preparation method described above.

[0012] Thirdly, an electrode for a supercapacitor, the electrode material comprising the electrode material, a conductive agent, and a binder.

[0013] Furthermore, the mass ratio of the electrode material, the conductive agent, and the binder is 80~90:5~10:5~10.

[0014] Fourthly, a method for preparing an electrode for a supercapacitor involves mixing an electrode material, a conductive agent, and a binder in an auxiliary solvent to obtain a slurry, and then coating the slurry onto carbon cloth to obtain an electrode for a supercapacitor.

[0015] Fifthly, a supercapacitor, said supercapacitor comprising the electrodes used in the aforementioned supercapacitor.

[0016] Furthermore, the supercapacitor also includes a solid electrolyte, which comprises PVA-KOH gel.

[0017] This invention provides a method for fabricating an all-solid-state flexible supercapacitor that is simple to process, has strong interfacial bonding, is flexible and stable, and is suitable for large-scale manufacturing. This method can achieve integrated design at three levels: electrode construction, electrolyte preparation, and device packaging. At the electrode level, a bimetallic MOF@MXene composite structure is introduced to enhance pseudocapacitive activity and electron transport. At the electrolyte level, a PVA–KOH gel system is used to balance ion conductivity and mechanical flexibility. At the device structure level, a lamination packaging technology of carbon cloth-based flexible electrodes, gel electrolyte, and a highly stable separator is used to achieve stable energy output and excellent mechanical reversibility.

[0018] The beneficial effects of this invention are: (1) Integrated device fabrication and simple and efficient process: The present invention adopts the "one-pot" in-situ synthesis strategy to achieve uniform growth of Ni / Co bimetallic MOF on the MXene surface, eliminating the need for multi-step intercalation and post-assembly processes; combined with flexible carbon cloth substrate and gel electrolyte encapsulation, it can realize integrated fabrication at the device level, with scalability and mass production potential.

[0019] (2) Bimetallic synergistic enhancement effect: Ni 2+ and Co 2+ The synergistic effect enhances the charge transfer rate and the density of electrochemical active sites, resulting in a more complete pseudocapacitive reaction and a significant increase in specific capacitance; at the same time, the Ni / Co ratio is adjustable to achieve the best match between capacity and stability.

[0020] (3) High conductivity interface and flexible structure compatibility: MXene's two-dimensional conductive network enhances the electron transport channel, and the carbon cloth substrate gives the whole excellent bending reversibility and tensile stability; under multiple curling and bending (0~180°) conditions, the capacitance retention rate still exceeds 97%.

[0021] (4) All-solid-state safety packaging design: PVA-KOH gel solid electrolyte and high mechanical strength diaphragm are used to avoid the risk of liquid electrolyte leakage; the device is packaged with polyimide tape to ensure long-term stable operation under external deformation or humidity conditions.

[0022] (5) Excellent electrochemical and cycling performance: The device manufactured in this invention exhibits excellent electrochemical and cycling performance at a power density of 750 W·kg⁻¹. -1 It has a power of 73.9 Wh·kg -1 With its high energy density and capacitance retention of over 80% after 10,000 cycles, it demonstrates excellent cycle life and device reliability.

[0023] (6) The all-solid-state flexible wearable supercapacitor of the present invention combines high electrochemical performance, excellent flexibility, and structural safety, and is suitable for flexible wearable electronic devices, smart textiles, electronic skin, and flexible display systems. The method is process-controllable, uses readily available raw materials, and is environmentally friendly, and has broad potential for industrial application. Attached Figure Description

[0024] Figure 1 The images are SEM images of the present invention; where a is the SEM of Comparative Example 1 and b is the SEM of Example 1. Figure 2 These are TEM and EDS images of the present invention; where a is the TEM of Comparative Example 1, b is the TEM of Example 1, and c is the EDS of Example 1. Figure 3 This is a cyclic voltammetry curve of the present invention; where a is Comparative Example 1 and b is Example 1; Figure 4 The graph shows the constant current charge-discharge curves of the three-electrode system of the present invention; where a is Comparative Example 1 and b is Example 1. Figure 5 From left to right are SEM and TEM of Comparative Example 3; Figure 6 Comparative Example 3 shows the CV and GCD curves; where a is the CV and b is the GCD. Figure 7 Mechanical performance testing of the device prepared in Example 2 of the present invention; wherein, a is the CV curve, b is the CV curve at different bending angles, and c is a physical image at different bending angles; Figure 8 The images show the device prepared in Embodiment 2 of the present invention in different states from left to right. Figure 9 The diagram shows the cycle life and charge-discharge performance of the device prepared in Example 2 of the present invention; where a is a Lagrangian diagram of the device's energy density and power density, and b is a cycle diagram. Detailed Implementation

[0025] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0026] The sources of materials and reagents are described in Table 1: Table 1 This embodiment relates to a method for preparing an electrode material, including the following steps: [The text abruptly ends here, so the translation stops.] 2+ Salt containing Co 2 + Salts, ligands and MXene (Ti3C2T) x Dispersed in an organic solvent, allowing metal ions Ni 2+ Co 2+ Anchored to the functional groups on the surface of MXene to obtain a dispersion; react the dispersion to obtain the electrode material Ni / Co-MOF@MXene.

[0027] Preferably, the Ni-containing compound described in this embodiment 2+ The salt and the Co-containing 2+ Ni in salt 2+ With Co 2+ The molar ratio is 1~2:1~2, for example 1:1, 1.5:1, 1~2, etc.; Ni in the dispersion 2+ The ratio of the amount of organic solvent used is (1~2) mmol: (15-30) mL, for example, 1 mmol: 15 mL, 2 mmol: 25 mL, etc. Ni in the dispersion 2+ The ratio of the ligand to the MXene is (1~2) mmol: (8~16) mmol: (10~20) mg, for example, 1 mmol: 8 mmol: 10 mg, 2 mmol: 15 mmol: 20 mg, etc.

[0028] Preferably, the Ni-containing compound described in this embodiment 2+ The salts include Ni(NO3)2; the salts containing Co 2+ The salts include Co(NO3)2; the ligands include BTC (1,3,5-benzenetricarboxylic acid); and the organic solvents include DMF (N,N-dimethylformamide).

[0029] Preferably, the reaction conditions for the dispersion described in this embodiment are: temperature of 105~130℃ and time of 15 h~24 h.

[0030] This embodiment also relates to an electrode material, which is prepared by the preparation method described above.

[0031] This embodiment also relates to an electrode for a supercapacitor, wherein the electrode material includes the electrode material, a conductive agent, and a binder.

[0032] Preferably, the mass ratio of the electrode material, the conductive agent, and the binder in this embodiment is 80~90:5~10:5~10, for example, 80:10:10, 90:5:5, etc.

[0033] This embodiment also relates to a method for preparing an electrode for a supercapacitor, wherein electrode material, conductive agent and binder are added to an auxiliary solvent and mixed to obtain a slurry, and the slurry is coated on carbon cloth to obtain an electrode for a supercapacitor.

[0034] This embodiment also relates to a supercapacitor, which includes the electrodes used in the supercapacitor described above.

[0035] Preferably, the supercapacitor in this embodiment further includes a solid electrolyte, which comprises PVA-KOH gel. The preparation method of the PVA-KOH gel solid electrolyte is as follows: 30-50 mL of deionized water is heated to 95°C, 4-6 g of polyvinyl alcohol is slowly added, and heating and stirring are continued until a clear gel appears. The mixture is then cooled to room temperature, and a KOH aqueous solution (KOH:H2O = 3-4 g:10-15 mL) is slowly added to obtain the PVA-KOH gel solid electrolyte.

[0036] Specifically, this embodiment provides a method for fabricating an all-solid-state flexible wearable supercapacitor electrode material and device, including the following specific steps: S1: Ni 2+ and Co 2+ Two metal ions were simultaneously dispersed in DMF (N,N-dimethylformamide) at a 1:1 molar ratio using a one-pot method and then sonicated. A ligand and MXene (Ti3C2T) were added to the resulting dispersion. x The process continues with sonication to anchor the metal ions to the functional groups on the MXene surface. The resulting solution is then transferred to a high-pressure reactor for reaction. After cooling to room temperature, the product is filtered, washed, and vacuum dried to obtain an all-solid-state flexible wearable supercapacitor electrode material. For example, 2-4 mmol of Ni(NO3)2·6(H2O) and Co(NO3)2·6(H2O) are simultaneously dispersed in 30-60 mL of DMF using a one-pot method at an ion ratio of 1:1 and then sonicated for 0.5-1 h. Compared with most existing single-metal MOFs, the Ni in this invention... 2+ and Co 2+The synergistic effect can enhance the charge transfer rate and electrochemical active site density, resulting in a more complete pseudocapacitive reaction and a significant increase in specific capacitance. Simultaneously, the Ni / Co ratio is adjustable, achieving an optimal match between capacity and stability. 16–32 mmol of the ligand and 20–40 mg of MXene are added to the resulting dispersion, and sonication is continued for 0.5–1 h until metal ions are anchored on the MXene surface. Compared with existing technologies, this invention employs a "one-pot" in-situ synthesis strategy to achieve uniform growth of Ni / Co bimetallic MOFs on the MXene surface, eliminating the need for multi-step intercalation and post-assembly processes. The chemical formulas involved include Formulas I to III: .

[0037] The ligand is BTC (1,3,5-benzenetricarboxylic acid), which is widely available and inexpensive, satisfying the cost control requirements for large-scale preparation. The well-dispersed solution is transferred to a high-pressure reactor and heated at 105-130℃ for 15-24 hours. After filtration, the product is washed several times with DMF and ethanol, respectively. Then, the product is placed in a vacuum oven at 70-80℃ overnight to obtain an all-solid-state flexible wearable supercapacitor electrode material.

[0038] S2: The obtained all-solid flexible wearable supercapacitor electrode material is used as the positive electrode material, and mixed with acetylene black and binder (PVDF) in a certain mass ratio. The mixture is placed in an agate mortar, and after adding auxiliary solvent, the mixture is ground into a slurry. The slurry is evenly coated on carbon cloth and vacuum dried to obtain a flexible electrode. For example, a fully solid-state flexible wearable supercapacitor electrode material was prepared as the positive electrode. The positive electrode material, acetylene black, and binder were mixed in a mass ratio of 80:10:10. The mixture was placed in an agate mortar, and 2-3 mL of auxiliary solvent was added. The mixture was then ground into a slurry, which was uniformly coated onto carbon cloth and dried overnight in a vacuum oven at 50°C to obtain the flexible electrode. The auxiliary solvent was a 1:1 volume ratio solution of NMP and 98% ethanol.

[0039] S3: Using activated carbon (AC) as the negative electrode material, the same flexible electrode is prepared according to the method in step S2. PVA-KOH gel is used as the electrolyte, and after adding a supercapacitor isolation membrane, it is encapsulated to form an all-solid-state flexible wearable supercapacitor.

[0040] For example, using the flexible electrode prepared in S2 as the positive electrode and activated carbon (AC) as the negative electrode material, the same flexible electrode can be prepared. Using PVA-KOH gel as the solid electrolyte, and encapsulating it with a supercapacitor separator, an all-solid-state flexible wearable supercapacitor can be formed.

[0041] The preparation method of the PVA-KOH gel solid electrolyte is as follows: 30-50 mL of deionized water is heated to 95°C, and 4-6 g of polyvinyl alcohol is slowly added. Heating and stirring continue until a clear gel forms. The mixture is then cooled to room temperature, and a KOH aqueous solution (KOH:H₂O = 3-4 g:10-15 mL) is slowly added to obtain the PVA-KOH gel solid electrolyte. The NKK-MPF30AC-100 type supercapacitor separator membrane is used, and polyimide tape is used for encapsulation.

[0042] The present invention will be further described below with reference to specific embodiments.

[0043] Example 1: Flexible Electrode (1) Preparation of electrode materials for all-solid-state flexible wearable supercapacitors.

[0044] This embodiment relates to a method for preparing electrode materials for an all-solid-state flexible wearable supercapacitor, including the following steps: Step S1: Disperse 2 mmol of Ni(NO3)2·6(H2O) and 2 mmol of Co(NO3)2·6(H2O) in 30 mL of DMF at an ion ratio of 1:1 and sonicate for 0.5 h. Step S2: Add 16 mmol BTC and 20 mg MXene to the solution obtained in step S1, and continue sonication for 0.5 h until the metal ions are anchored on the surface of MXene; Step S3: The well-dispersed solution from step S2 was transferred to a high-pressure reactor and heated at 105°C for 15 h. After filtration, the solution was washed several times with DMF and ethanol, respectively. The product was then placed in a vacuum oven at 70°C overnight to obtain an all-solid-state flexible wearable supercapacitor electrode material, labeled Ni1Co1-MOF@MX for easy comparison. Figure 1 b and Figure 2 As shown in Figures b and c, the SEM and TEM (EDS) images of the product are shown respectively, which clearly demonstrate the morphology of the electrode material.

[0045] (2) Electrode fabrication for all-solid-state flexible wearable supercapacitors.

[0046] A method for fabricating electrodes for all-solid-state flexible wearable supercapacitors includes the following steps: Step S4: Using the electrode material for an all-solid-state flexible wearable supercapacitor prepared in Step S3 as the positive electrode, mix the positive electrode material, acetylene black, and binder at a mass ratio of 80:10:10. Place the mixture in an agate mortar, add 2 mL of a 1:1 volume ratio NMP and ethanol (98%) solution, and grind the mixture into a slurry. Coat the slurry evenly onto a carbon cloth with a thickness of 0.2 mm and an area of ​​1 × 2 cm, controlling the loading of the active material in the coating to be 1.5 mg·cm³. -2 The flexible electrode was obtained by drying it overnight in a vacuum oven at 50°C.

[0047] Example 2: Supercapacitor (1) Preparation of electrode materials for all-solid-state flexible wearable supercapacitors.

[0048] This embodiment describes a method for preparing electrode materials for an all-solid-state flexible wearable supercapacitor, comprising the following steps: Step S1: Simultaneously disperse 3 mmol of Ni(NO3)2·6(H2O) and 3 mmol of Co(NO3)2·6(H2O) in 40 mL of DMF and sonicate for 0.5 h; Step S2: Add 24 mmol BTC and 30 mg MXene to the solution obtained in step S1, and continue sonication for 0.5 h until the metal ions are anchored on the surface of MXene; Step S3: Transfer the well dispersed solution from step S2 to a high-pressure reactor, heat at 105°C for 15 h, filter, and wash several times with DMF and ethanol respectively. Then place the product in a vacuum oven at 70°C overnight to obtain an electrode material for an all-solid-state flexible wearable supercapacitor.

[0049] (2) Fabrication of all-solid-state flexible wearable supercapacitor.

[0050] The method for fabricating an all-solid-state flexible wearable supercapacitor includes the following steps: Step S4: Using the electrode material for an all-solid-state flexible wearable supercapacitor prepared in Step S3 as the positive electrode, mix the positive electrode material, acetylene black, and binder at a mass ratio of 80:10:10. Place the mixture in an agate mortar, add 3 mL of a 1:1 volume ratio NMP and ethanol (98%) solution, and grind the mixture into a slurry. Coat the slurry evenly onto a carbon cloth with a thickness of 0.3 mm and an area of ​​1 × 2 cm, controlling the active material loading of the coating to be 2.0 mg·cm³. -2 The flexible electrode was obtained by drying it overnight in a vacuum oven at 50°C. S5: Using activated carbon (AC) as the negative electrode material, prepare the same flexible electrode according to the method in step S4; measure 40 mL of deionized water and heat it to 95 °C, slowly add 5 g of polyvinyl alcohol and continue heating and stirring until a clear gel appears, then cool to room temperature, slowly add KOH aqueous solution (KOH:H2O = 4 g:15 mL) to obtain PVA-KOH gel solid electrolyte; select NKK-MPF30AC-100 type supercapacitor separator membrane, construct it in a five-layer stacking manner, namely "positive electrode / solid electrolyte / separator / solid electrolyte / negative electrode", and encapsulate it with polyimide tape to obtain an all-solid flexible wearable supercapacitor.

[0051] Comparative Example 1 (1) Preparation of electrode materials for all-solid-state flexible wearable supercapacitors.

[0052] The difference between this comparative example and Example 1 is that MXene is not added in step S2. This comparative example provides a method for preparing electrode materials for an all-solid-state flexible wearable supercapacitor, specifically including the following steps: Step S1: Disperse 2 mmol of Ni(NO3)2·6(H2O) and Co(NO3)2·6(H2O) in 30 mL of DMF at an ion ratio of 1:1 and sonicate for 0.5 h. Step S2: Add 16 mmol BTC to the solution obtained in step S1 and continue sonication for 0.5 h; Step S3: The well-dispersed solution from step S2 was transferred to a high-pressure reactor and heated at 105°C for 15 h. After filtration, the product was washed several times with DMF and ethanol, respectively. The product was then placed in a vacuum oven at 70°C overnight to obtain a fully solid-state flexible wearable supercapacitor electrode material, labeled Ni1Co1-MOF for easy comparison. Figure 1 a and Figure 2 As shown in Figure a, the SEM and TEM images of the product are shown respectively, which clearly demonstrate the morphology of the product.

[0053] (2) Preparation of electrodes for all-solid-state flexible wearable supercapacitors.

[0054] A method for fabricating electrodes for an all-solid-state flexible wearable supercapacitor includes the following steps: Step S4: Using the all-solid-state flexible wearable supercapacitor electrode material prepared in Step S3 as the positive electrode, mix the positive electrode material, acetylene black, and binder at a mass ratio of 80:10:10. Place the mixture in an agate mortar, add 2 mL of a 1:1 volume ratio NMP and ethanol (98%) solution, and grind the mixture into a slurry. Coat the slurry evenly onto a carbon cloth with a thickness of 0.2 mm and an area of ​​1 × 2 cm, controlling the active material loading of the coating to be 1.5 mg·cm³. -2 The flexible electrode was obtained by drying it overnight in a vacuum oven at 50°C.

[0055] Comparative Example 2 (1) Preparation of electrode materials for all-solid-state flexible wearable supercapacitors.

[0056] The difference between this comparative example and Example 1 lies in the Ni step S1. 2+ and Co 2+ The molar ratio is 1:3. This comparative example provides a method for preparing electrode materials for an all-solid-state flexible wearable supercapacitor, specifically including the following steps: Step S1: Disperse 2 mmol of Ni(NO3)2·6(H2O) and 6 mmol of Co(NO3)2·6(H2O) in 30 mL of DMF at an ion ratio of 1:3 and sonicate for 0.5 h. Step S2: Add 16 mmol BTC and 20 mg MXene to the solution obtained in step S1, and continue sonication for 0.5 h until the metal ions are anchored on the surface of MXene; Step S3: The well dispersed solution from step S2 was transferred to a high-pressure reactor and heated at 105°C for 15 h. The mixture was then filtered and washed several times with DMF and ethanol. The product was then placed in a vacuum oven at 70°C overnight to obtain a fully solid-state flexible wearable supercapacitor electrode material, which was labeled as Ni1Co3-MOF@MX for easy comparison. (1) Fabrication of electrodes for all-solid-state flexible wearable supercapacitors.

[0057] Step S4: Using the all-solid-state flexible wearable supercapacitor electrode material prepared in Step S3 as the positive electrode, mix the positive electrode material, acetylene black, and binder at a mass ratio of 80:10:10. Place the mixture in an agate mortar, add 2 mL of a 1:1 volume ratio NMP and ethanol (98%) solution, and grind the mixture into a slurry. Coat the slurry evenly onto a carbon cloth with a thickness of 0.2 mm and an area of ​​1 × 2 cm, controlling the active material loading of the coating to be 1.5 mg·cm³. -2 The flexible electrode was obtained by drying it overnight in a vacuum oven at 50°C.

[0058] Comparative Example 3 (1) Preparation of electrode materials for all-solid-state flexible wearable supercapacitors: This embodiment relates to a method for preparing electrode materials for an all-solid-state flexible wearable supercapacitor, including the following steps: Step S1: Disperse 2 mmol of Ni(NO3)2·6(H2O) in 30 mL of DMF and sonicate for 0.5 h; Step S2: Add 16 mmol BTC and 20 mg MXene to the solution obtained in step S1, and continue sonication for 0.5 h until the metal ions are anchored on the surface of MXene; Step S3: Transfer the well dispersed solution from step S2 to a high-pressure reactor, heat at 105°C for 15 h, filter, and wash several times with DMF and ethanol respectively. Then place the product in a vacuum oven at 70°C overnight to obtain an all-solid-state flexible wearable supercapacitor electrode material, which is labeled as Ni-MOF@MX for easy comparison.

[0059] (2) Electrode fabrication for all-solid-state flexible wearable supercapacitors: A method for fabricating electrodes for all-solid-state flexible wearable supercapacitors includes the following steps: Step S4: Using the electrode material for an all-solid-state flexible wearable supercapacitor prepared in Step S3 as the positive electrode, mix the positive electrode material, acetylene black, and binder at a mass ratio of 80:10:10. Place the mixture in an agate mortar, add 2 mL of a 1:1 volume ratio NMP and ethanol (98%) solution, and grind the mixture into a slurry. Coat the slurry evenly onto a carbon cloth with a thickness of 0.2 mm and an area of ​​1 × 2 cm, controlling the loading of the active material in the coating to be 1.5 mg·cm³. -2 The flexible electrode was obtained by drying it overnight in a vacuum oven at 50°C.

[0060] Test case 1. The materials and electrodes prepared in Example 1 and Comparative Examples 1 to 3 are compared.

[0061] (1) Structural characterization: By comparison Figure 1 As can be seen from a and b in the figures, there is obvious stacking and aggregation among the pure MOF particles; after being combined with MXene, the MXene sheets act as a matrix, and the MOF particles can still maintain their original morphology and particle size, loaded on the MXene surface, and are more ordered. Figure 5As shown, SEM and TEM images of the product of Comparative Example 3 are displayed, which clearly show the morphology of the electrode material. The images show SEM and TEM images of Ni-MOF@MXene. It can be seen that the structure is loose after the single ion combines with MXene and does not form a stable composite structure, which is speculated to affect the cycling stability of the electrode.

[0062] (2) Electrode performance: ① Steps for detecting cyclic voltammetry curves: a. A three-electrode testing system was adopted, with the electrodes obtained in Example 1 and Comparative Examples 1 and 3 as working electrodes, Pt as counter electrode, and Hg / HgO as reference electrode; b. at 2 mV·s -1 5 mV·s -1 10 mV·s -1 20 mV·s -1 50 mV·s -1 100 mV·s -1 Cyclic voltammetry (CV) curves were tested at different scan rates. c. Mass specific capacitance (Cs, Fg) -1 The calculation can be performed using the cyclic voltammetry curve according to equation (1): ; In formula (1) , , , These represent the integral area of ​​the CV curve, the mass of the active substance (g), and the scan rate (mV·s), respectively. -1 ) and voltage window (V).

[0063] Depend on Figure 3 And as can be calculated using formula (1), 2 mV·s -1 At scan speed, Example 1 ( Figure 3 The specific capacitance of the electrode material in (b) is approximately 1493.6 F·g. -1 Comparative Example 1 ( Figure 3 The specific capacitance in (a) is 1093.0 F·g. -1 The electrochemical specific capacitance of Comparative Example 3 is 1016.7 F·g. -1 ( Figure 6 (a and b). The results show that the electrode material in Embodiment 1 of the present invention is an ideal material for use in all-solid-state flexible wearable supercapacitors.

[0064] ② Experimental steps for charging and discharging curves: a. A three-electrode testing system was adopted, with the electrodes obtained in Example 1, Comparative Example 2, and Comparative Example 3 as working electrodes, Pt as counter electrode, and Hg / HgO as reference electrode; b. In 1A·g -1 2A·g -1 3A·g -1 5A·g -1 10, 20 A·g -1 The constant current charge-discharge curve (GCD) was tested at the sweep rate. c. Mass specific capacitance (Cs, F·g) -1 The calculation can be performed using constant current charge-discharge curves: It can also be calculated using the constant current charge-discharge curve of the three-electrode system, as shown in formula (2) below: ; In equation (2), , , , The values ​​are the discharge current (A), discharge time (s), voltage window (V), and mass (g) of the active material in the GCD curve, respectively.

[0065] Depend on Figure 4 From the calculations using a and b and formula (2), it can be seen that the electrode material of Comparative Example 2 is 1 A·g -1 The specific capacitance is approximately 664.0 F·g -1 ;Depend on Figure 6 In Figure b, the GCD curve of Comparative Example 3 is given. The specific capacitance of Comparative Example 3 can be calculated from this curve and formula (2) to be approximately 1016.7 F·g. -1 ; while the electrode material of Example 1 is 1 A·g -1 The specific capacitance is 1493.6 F·g -1 .

[0066] The above comparison shows that, after testing with a three-electrode system, the electrode material of the all-solid-state flexible wearable supercapacitor of this invention has a large specific capacitance and has broad application prospects in the field of rapid energy storage.

[0067] 2. Performance testing of the device prepared in Example 2.

[0068] (1) Mechanical performance testing: Figure 7 Mechanical performance testing of the device prepared in Example 2: The CV curves at different bending angles (0°, 45°, 90°, 180°) remained consistent, indicating that the device has excellent stability and mechanical performance. Digital photos taken during the testing process also confirmed the good mechanical performance of the device.

[0069] The mechanical performance testing specifically involved evaluating the mechanical stability of the flexible supercapacitor through electrochemical tests at different bending angles. The device was fixed on a flexible substrate, and the electrical connections at both ends of the device remained unchanged under bending conditions of 0°, 45°, 90°, and 180°. Cyclic voltammetry (CV) curves were tested at the same scan rate (e.g., 20 mV·s⁻¹), and the specific capacitance and capacitance retention rate were calculated based on the integrated current. The results showed that the CV curves at each bending angle largely overlapped, and the specific capacitance retention rate was close to 100%, indicating that the flexible supercapacitor maintained stable electrochemical performance under various bending deformations, demonstrating excellent mechanical flexibility and structural reliability.

[0070] Figure 8 The image shows a physical diagram of the device prepared in Example 2. Two devices connected in series can drive red and blue LEDs, and their performance is not affected after bending.

[0071] (2) Cycle life and charge / discharge performance: Figure 9 The circuit life and charge-discharge performance of the device prepared in Example 2 are shown in the graph. Figure 9 In the figure, 'a' is the Lagrangian plot of the device's energy density and power density, which is calculated using formulas (3) and (4): ; In equation (3), C is the specific capacitance (F·g) -1 V is the operating voltage (V), and ∆t is the discharge time (s) in equation (4). This is calculated using equations (3) and (4). When the device operates at a power density of 750 W·kg⁻¹, ... -1 It has a power of 73.9 Wh·kg -1 The energy density, when the power density increases to 15000 W·kg -1 At that time, the energy density remained at 40.7 Wh·kg -1 ;like Figure 9 In Figure b, after 10,000 cycles, the device retains 82% of its capacity and has a coulombic efficiency of 97%, demonstrating that the all-solid-state flexible supercapacitor has good cycle life and charge / discharge reliability, making it suitable for applications requiring frequent charge and discharge.

[0072] In summary, to overcome the problems of insufficient electrode conductivity, poor interface bonding, unstable encapsulation, and limited flexibility and durability of existing all-solid-state flexible supercapacitors, this invention provides a method for fabricating electrodes and devices for all-solid-state flexible wearable supercapacitors. This method achieves high specific capacitance, high power density, and excellent mechanical stability of flexible energy storage devices through the design of bimetallic Ni / Co-MOF@MXene composite electrode materials, optimization of gel solid electrolyte, and integrated encapsulation process. It also features simple structure and scalable fabrication.

[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an electrode material, characterized in that, The steps include: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] 2+ Salt containing Co 2+ The salt, ligands, and MXene are dispersed in an organic solvent, allowing the metal ions Ni to be dispersed. 2+ Co 2+ Anchored to the functional groups on the surface of MXene to obtain a dispersion; react the dispersion to obtain the electrode material Ni / Co-MOF@MXene.

2. The method for preparing an electrode material according to claim 1, characterized in that, The Ni-containing 2+ The salt and the Co-containing 2+ Ni in salt 2+ With Co 2+ The molar ratio is 1~2:1~2; Ni in the dispersion 2+ The ratio of the amount of organic solvent used to that used organic solvent is (1~2) mmol: (15-30) mL; Ni in the dispersion 2+ The ratio of the ligand to the MXene is (1~2) mmol: (8~16) mmol: (10~20) mg.

3. The method for preparing an electrode material according to claim 1, characterized in that, The Ni-containing 2+ The salts include at least one of Ni(NO3)2 and Ni(CH3COO)2; The containing Co 2+ The salts include at least one of Co(NO3)2 and Co(CH3COO)2; The ligand is BTC; The organic solvent includes DMF.

4. The method for preparing an electrode material according to claim 1, characterized in that, The reaction conditions for the dispersion are: temperature of 105~130℃ and time of 15 h~24 h.

5. An electrode material, characterized in that, The electrode material is prepared by the preparation method according to any one of claims 1 to 4.

6. An electrode for a supercapacitor, characterized in that, The electrode material includes the electrode material as described in claim 5, a conductive agent, and a binder.

7. An electrode for a supercapacitor according to claim 6, characterized in that, The mass ratio of the electrode material, the conductive agent, and the binder is 80~90:5~10:5~10.

8. A method for preparing an electrode for a supercapacitor according to any one of claims 6 to 7, characterized in that, Electrode material, conductive agent and binder are mixed in an auxiliary solvent to obtain a slurry. The slurry is then coated onto carbon cloth to obtain an electrode for a supercapacitor.

9. A supercapacitor, characterized in that, The supercapacitor includes an electrode for a supercapacitor as described in any one of claims 6 to 7.

10. A supercapacitor according to claim 9, characterized in that, The supercapacitor also includes a solid electrolyte, which includes PVA-KOH gel.

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