A high-capacity capacitor electrode material and a method for preparing the same
By combining lignin with polyacrylonitrile and pitch, and combining element doping and surface coating processes, high-capacity capacitor electrode materials were prepared, solving the problems of low capacitance and poor cycle stability of lignin carbon materials, and realizing capacitor electrodes with high specific capacity and high cycle stability.
Patent Information
- Application Number
- CN202610520884.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-20
- Publication Date
- 2026-07-14
AI Technical Summary
When existing lignin-carbon materials are used as capacitor electrodes, they exhibit low capacitance and poor cycle stability.
Polythiophene-modified composite carbon nanofibers were prepared by combining lignin with polyacrylonitrile and pitch, along with elemental doping and surface coating processes. Zinc and iron-modified composite carbon nanofibers were then prepared by electrospinning and high-temperature carbonization processes to form a polythiophene coating layer, thereby enhancing electrochemical performance.
It improves the specific capacitance and cycle stability of the capacitor electrode, reduces the charge transfer resistance and ion diffusion resistance in the electrochemical reaction, enhances the wettability of the electrolyte, and improves the electrochemical performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of capacitor electrode material technology, specifically to a high-capacity capacitor electrode material and its preparation method. Background Technology
[0002] Carbon materials are the main components of capacitor electrode materials. The preparation of traditional carbon materials heavily relies on fossil fuels such as oil, coal, and natural gas. Given the depletion of non-renewable energy sources and environmental pollution issues, the exploration and development of new green energy sources that can support future energy demand growth is urgently needed. Lignin, a renewable resource derived from the earth, is abundant and inexpensive, making it an ideal alternative to fossil fuels. Converting lignin into high-performance carbon materials can not only effectively reduce the production cost of capacitor electrodes and decrease environmental pollution, but also promote resource recycling, injecting new vitality into the sustainable development of capacitor electrode materials.
[0003] Currently, the direct application of lignin-based carbon materials to capacitor electrodes suffers from low capacitance and poor cycle stability. This application utilizes lignin as a biomass carbon material, combining it with conventional carbon materials such as polyacrylonitrile and pitch. Through elemental doping and surface coating processes, high specific capacity and high cycle stability modification of the composite carbon fiber are achieved. Summary of the Invention
[0004] The purpose of this invention is to provide a high-capacity capacitor electrode material and its preparation method to solve the problems existing in the prior art.
[0005] A high-capacity capacitor electrode material is prepared by polymerizing and depositing thiophene and 3-aminomethylthiophene onto composite carbon nanofibers to obtain polythiophene-modified composite carbon nanofibers; reacting polythiophene-modified composite carbon nanofibers with poly(ethylene glycol) methacrylate to obtain functionalized composite carbon nanofibers; mixing and grinding the functionalized composite carbon nanofibers, acetylene black, and adhesive to obtain a mixed slurry; coating the mixed slurry onto a nickel foam substrate; and drying to obtain the high-capacity capacitor electrode material.
[0006] Furthermore, the composite carbon nanofibers are obtained by high-temperature carbonization of composite fiber precursors.
[0007] Furthermore, the composite fiber precursor is obtained by uniformly mixing polyacrylonitrile, lignin, pitch, zinc acetate, and ferric acetylacetone to prepare a spinning solution, and then electrospinning it.
[0008] Furthermore, the preparation method of the high-capacity capacitor electrode material includes the following steps: S1: Mix asphalt and tetrahydrofuran at a mass ratio of 1:(5~6) to prepare an asphalt solution; add polyacrylonitrile and lignin to N,N-dimethylformamide at a mass ratio of 5~6 times that of lignin, stir at room temperature for 10~14h, add the asphalt solution, continue stirring for 20~30min, add zinc acetate and acetylacetone iron, stir at 35~45℃ for 3~5h to obtain a mixed spinning solution; place the spinning solution in an electrospinning device for electrospinning to obtain composite fiber precursor; S2: Place the composite fiber precursor in an electric furnace and heat it to 220~280℃ at a rate of 2℃ / min, and keep it at this temperature for 100~120min. Under nitrogen protection, heat it to 900~1000℃ at a rate of 5℃ / min, and keep it at this temperature for 60~70min. Cool it to room temperature to obtain composite carbon nanofibers. S3: Mix composite carbon nanofibers, ferric chloride, and chloroform in a mass ratio of 1:(0.04~0.06):(20~30) until homogeneous, sonicate for 30~40 min, add 16~20 times the mass of thiophene solution of composite carbon nanofibers under nitrogen protection, stir and react at room temperature for 20~24 h, filter, wash 3~5 times each with anhydrous ethanol and deionized water, and vacuum dry at 50~60℃ for 20~24 h to obtain polythiophene modified composite carbon nanofibers; S4: Polythiophene-modified composite carbon nanofibers and N,N-dimethylformamide are mixed evenly at a mass ratio of 1:(20~30), sonicated for 30~40 min, poly(ethylene glycol) methacrylate is added, stirred at 50~60℃ for 8~10 h, filtered, washed 3~5 times each with anhydrous ethanol and deionized water, and vacuum dried at 50~60℃ for 20~24 h to obtain functionalized composite carbon nanofibers; S5: Mix functionalized composite carbon nanofibers, acetylene black, and binder evenly, add N-methylpyrrolidone to control the solid content at 30%, grind for 1-2 hours to obtain a mixed slurry; coat the mixed slurry evenly on a nickel foam substrate, dry at 100-110℃ for 4-6 hours to obtain a high-capacity capacitor electrode material.
[0009] Furthermore, the dosage relationship of polyacrylonitrile, lignin, asphalt, zinc acetate, and ferric acetylacetone in step S1 is as follows: by mass parts, polyacrylonitrile 10-12 parts, lignin 20-30 parts, asphalt 6-8 parts, zinc acetate 1.8-2.2 parts, and ferric acetylacetone 1.3-1.5 parts.
[0010] Furthermore, the electrospinning process parameters in step S1 are set as follows: applied voltage of 22~26kV, feed rate of 1~1.2ml / h, collection rate of 400~600r / min, collection distance of 14~16cm, and vacuum drying at 60~70℃ for 10~12h.
[0011] Furthermore, the preparation method of the thiophene solution in step S3 is as follows: thiophene and 3-aminomethylthiophene are added to chloroform at a molar ratio of 1:(1.2~1.4) in 7~8 times the mass of thiophene, and mixed evenly to prepare a thiophene solution.
[0012] Furthermore, the average molecular weight Mn of the poly(ethylene glycol) methacrylate described in step S4 is 500.
[0013] Furthermore, the amount of poly(ethylene glycol) methacrylate added in step S4 is 2 to 2.2 times the mass of the polythiophene-modified composite carbon nanofibers.
[0014] Furthermore, the dosage relationship of the functionalized composite carbon nanofibers, acetylene black, and adhesive in step S5 is as follows: by mass parts, 78-82 parts of functionalized composite carbon nanofibers, 9-11 parts of acetylene black, and 9-11 parts of adhesive.
[0015] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following beneficial effects: (1) Zinc and iron modified composite carbon nanofibers were prepared by using acetylacetone iron as a ferrite precursor, zinc acetate as a zinc oxide precursor, and polyacrylonitrile, lignin and pitch as carbon sources, combined with electrospinning and high-temperature carbonization processes. The iron in the composite carbon nanofibers is mainly ferric oxide and magnetite. When used as capacitor electrode materials, ferric oxide is conducive to the rapid transport of electrons, while magnetite promotes the rapid diffusion of electrolyte. The combination of the two can effectively reduce the charge transfer resistance and ion diffusion resistance in the electrochemical reaction process. The doping of iron oxide also endows carbon nanofibers with certain redox activity, producing a pseudocapacitive effect, which makes them have a higher specific capacitance value when used as capacitor electrode materials. The doping of amorphous zinc oxide provides more electrochemical active sites. Through the rapid electrochemical adsorption / desorption of electrolyte, the surface redox reaction is induced, which further improves the electrochemical performance of capacitor electrodes.
[0016] (2) Thiophene and 3-aminomethylthiophene are polymerized and deposited on the surface of composite carbon nanofibers by oxidative polymerization to form a polythiophene coating layer. At the same time, amino groups are introduced on the surface. Polythiophene is a conductive polymer. When combined with carbon nanofibers, it can further enhance the specific capacitance of the composite material. The amino groups on the surface undergo Michael addition reaction with the α-β unsaturated carbon-carbon double bonds on poly(ethylene glycol) methacrylate. A large number of hydrophilic polyethylene glycol structures are grafted onto the surface of the functionalized composite carbon nanofibers to enhance the wettability with the electrolyte and further improve the electrochemical performance of the capacitor electrode. Detailed Implementation
[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0018] In the following examples and comparative examples, The polyacrylonitrile used was model P750088, purchased from Maclean's Reagent Co., Ltd. The lignin used was alkali lignin with a purity of 95%, purchased from Sigma-Aldrich, USA. The asphalt used was mesophase asphalt, purchased from Hebei Xiangbei New Material Technology Co., Ltd. The adhesive used was polytetrafluoroethylene, purchased from Maclean's Reagent Co., Ltd. The average molecular weight of the poly(ethylene glycol) methacrylate used was Mn=500, and it was purchased from Sigma-Aldrich, USA. Example 1:
[0019] A method for preparing a high-capacity capacitor electrode material includes the following preparation steps: S1: Weigh 10 parts polyacrylonitrile, 20 parts lignin, 6 parts asphalt, 1.8 parts zinc acetate, and 1.3 parts acetylacetone iron by mass. Mix asphalt and tetrahydrofuran at a mass ratio of 1:5 to prepare an asphalt solution. Add polyacrylonitrile and lignin to N,N-dimethylformamide at 5 times the mass of lignin and stir at room temperature for 10 hours. Add the asphalt solution and continue stirring for 20 minutes. Add zinc acetate and acetylacetone iron and stir at 35°C for 5 hours to obtain a mixed spinning solution. Place the spinning solution in an electrospinning apparatus for electrospinning. Set the applied voltage to 22kV, the feed rate to 1ml / h, the collection rate to 400r / min, and the collection distance to 14cm. Vacuum dry at 60°C for 12 hours to obtain composite fiber precursor. S2: The composite fiber filament is placed in an electric furnace and heated to 220°C at a rate of 2°C / min, and held at this temperature for 120 min. Under nitrogen protection, the temperature is increased to 900°C at a rate of 5°C / min, and held at this temperature for 70 min. The composite carbon nanofiber is then cooled to room temperature to obtain the composite carbon nanofiber. S3: Thiophene and 3-aminomethylthiophene were added to chloroform at a molar ratio of 1:1.2 to 7 times the mass of thiophene and mixed evenly to prepare a thiophene solution; composite carbon nanofibers, ferric chloride, and chloroform were mixed evenly at a mass ratio of 1:0.04:20 and sonicated for 30 min. Under nitrogen protection, 16 times the mass of the thiophene solution of the composite carbon nanofibers was added and stirred at room temperature for 20 h. The mixture was filtered, washed 3 times each with anhydrous ethanol and deionized water, and dried under vacuum at 50 °C for 24 h to obtain polythiophene-modified composite carbon nanofibers. S4: Polythiophene-modified composite carbon nanofibers and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:20, and sonicated for 30 min. Poly(ethylene glycol) methacrylate with a mass of 2 times that of polythiophene-modified composite carbon nanofibers was added, and the mixture was stirred at 50 °C for 10 h. The mixture was filtered, washed 3 times each with anhydrous ethanol and deionized water, and vacuum dried at 50 °C for 24 h to obtain functionalized composite carbon nanofibers. S5: Mix 78 parts of functionalized composite carbon nanofibers, 9 parts of acetylene black, and 9 parts of polytetrafluoroethylene evenly, add N-methylpyrrolidone to control the solid content at 30%, grind for 1 hour to obtain a mixed slurry; coat the mixed slurry evenly on a nickel foam substrate, dry at 100℃ for 6 hours to obtain a high-capacity capacitor electrode material. Example 2:
[0020] A method for preparing a high-capacity capacitor electrode material includes the following preparation steps: S1: Weigh 11 parts polyacrylonitrile, 25 parts lignin, 7 parts asphalt, 2 parts zinc acetate, and 1.4 parts acetylacetone iron by mass. Mix asphalt and tetrahydrofuran at a mass ratio of 1:5.5 to prepare an asphalt solution. Add polyacrylonitrile and lignin to N,N-dimethylformamide at 5.5 times the mass of lignin and stir at room temperature for 12 hours. Add the asphalt solution and continue stirring for 25 minutes. Add zinc acetate and acetylacetone iron and stir at 40°C for 4 hours to obtain a mixed spinning solution. Place the spinning solution in an electrospinning apparatus for electrospinning. Set the applied voltage to 24kV, the feed rate to 1.1ml / h, the collection rate to 500r / min, and the collection distance to 15cm. Vacuum dry at 65°C for 11 hours to obtain composite fiber precursor. S2: The composite fiber filament is placed in an electric furnace and heated to 250°C at a rate of 2°C / min, and held at this temperature for 110 min. Under nitrogen protection, the temperature is increased to 950°C at a rate of 5°C / min, and held at this temperature for 65 min. The composite carbon nanofiber is then cooled to room temperature to obtain the composite carbon nanofiber. S3: Thiophene and 3-aminomethylthiophene were added to chloroform at a molar ratio of 1:1.3 and mixed evenly to prepare a thiophene solution; composite carbon nanofibers, ferric chloride, and chloroform were mixed evenly at a mass ratio of 1:0.05:25 and sonicated for 35 min. Under nitrogen protection, thiophene solution at a mass ratio of 18 times that of composite carbon nanofibers was added, and the mixture was stirred and reacted at room temperature for 22 h. The mixture was filtered, washed 4 times each with anhydrous ethanol and deionized water, and dried under vacuum at 55 °C for 22 h to obtain polythiophene-modified composite carbon nanofibers. S4: Polythiophene-modified composite carbon nanofibers and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:25, and sonicated for 35 min. Poly(ethylene glycol) methacrylate with a mass of 2.1 times that of the polythiophene-modified composite carbon nanofibers was added, and the mixture was stirred at 55 °C for 9 h. After filtration, the mixture was washed 4 times each with anhydrous ethanol and deionized water, and then vacuum dried at 55 °C for 22 h to obtain functionalized composite carbon nanofibers. S5: Mix 80 parts of functionalized composite carbon nanofiber, 10 parts of acetylene black, and 10 parts of polytetrafluoroethylene evenly, add N-methylpyrrolidone to control the solid content at 30%, grind for 1.5 hours to obtain a mixed slurry; coat the mixed slurry evenly on a nickel foam substrate, dry at 105℃ for 5 hours to obtain a high-capacity capacitor electrode material. Example 3:
[0021] A method for preparing a high-capacity capacitor electrode material includes the following preparation steps: S1: Weigh 12 parts polyacrylonitrile, 30 parts lignin, 8 parts asphalt, 2.2 parts zinc acetate, and 1.5 parts acetylacetone iron by mass. Mix asphalt and tetrahydrofuran at a mass ratio of 1:6 to prepare an asphalt solution. Add polyacrylonitrile and lignin to N,N-dimethylformamide at 6 times the mass of lignin and stir at room temperature for 14 hours. Add the asphalt solution and continue stirring for 30 minutes. Add zinc acetate and acetylacetone iron and stir at 45°C for 3 hours to obtain a mixed spinning solution. Place the spinning solution in an electrospinning apparatus for electrospinning. Set the applied voltage to 26kV, the feed rate to 1.2ml / h, the collection rate to 600r / min, and the collection distance to 16cm. Vacuum dry at 70°C for 10 hours to obtain composite fiber precursor. S2: The composite fiber precursor is placed in an electric furnace and heated to 280°C at a rate of 2°C / min, and held at this temperature for 100 min. Under nitrogen protection, the temperature is increased to 1000°C at a rate of 5°C / min, and held at this temperature for 60 min. The composite carbon nanofiber is then cooled to room temperature to obtain the composite carbon nanofiber. S3: Thiophene and 3-aminomethylthiophene were added to chloroform at a molar ratio of 1:1.4 to 8 times the mass of thiophene and mixed evenly to prepare a thiophene solution; composite carbon nanofibers, ferric chloride, and chloroform were mixed evenly at a mass ratio of 1:0.06:30 and sonicated for 40 min. Under nitrogen protection, 20 times the mass of the thiophene solution of the composite carbon nanofibers were added and stirred at room temperature for 24 h. After filtration, the mixture was washed 5 times each with anhydrous ethanol and deionized water and dried under vacuum at 60 °C for 20 h to obtain polythiophene-modified composite carbon nanofibers. S4: Polythiophene-modified composite carbon nanofibers and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:30, and sonicated for 40 min. Poly(ethylene glycol) methacrylate with a mass of 2.2 times that of the polythiophene-modified composite carbon nanofibers was added, and the mixture was stirred at 60 °C for 8 h. After filtration, the mixture was washed 5 times each with anhydrous ethanol and deionized water, and then vacuum dried at 60 °C for 20 h to obtain functionalized composite carbon nanofibers. S5: Mix 82 parts of functionalized composite carbon nanofibers, 11 parts of acetylene black, and 11 parts of polytetrafluoroethylene evenly, add N-methylpyrrolidone to control the solid content at 30%, grind for 2 hours to obtain a mixed slurry; coat the mixed slurry evenly on a nickel foam substrate, dry at 110℃ for 4 hours to obtain a high-capacity capacitor electrode material.
[0022] Comparative Example 1: The difference between the preparation method of the high-capacity capacitor electrode material of Comparative Example 1 and Example 2 is that step S1 is different. In step S1 of Comparative Example 1, zinc acetate is not added when preparing the composite fiber precursor.
[0023] Comparative Example 2: The difference between the preparation method of the high-capacity capacitor electrode material in Comparative Example 2 and Example 2 is that step S1 is different. In Comparative Example 2, "iron acetylacetone" is not added in step S1 when preparing the composite fiber precursor.
[0024] Comparative Example 3: The difference between the preparation method of the high-capacity capacitor electrode material in Comparative Example 3 and Example 2 is that step S4 is omitted, and the "functionalized composite carbon nanofibers" in step S5 are replaced with the "polythiophene-modified composite carbon nanofibers" prepared in step S3.
[0025] Comparative Example 4: The difference between the preparation method of the high-capacity capacitor electrode material in Comparative Example 4 and Example 2 is that steps S3 and S4 are omitted, and the "functionalized composite carbon nanofibers" in step S5 are replaced with the "composite carbon nanofibers" prepared in step S2.
[0026] Test case Electrochemical performance testing In this invention, the embodiments and comparative examples use the working electrode, the Ag / AgCl electrode as the reference electrode, a platinum sheet as the auxiliary electrode, and a 6M KOH solution as the electrolyte. Specific capacitance and cycle performance are obtained through constant current charge-discharge tests. The charge-discharge voltage range is set to -0.5 V to 0.5 V, and the current density is set to 0.5 A / g.
[0027] Specific capacity: CS = (I × t) / (m × V), where specific capacity C S The units are (F / g), I represents the discharge current in (A), t represents the discharge time in (s), V represents the voltage change between the electrodes in (V), and m represents the mass of the active material in (m).
[0028] Cyclic performance: The charge / discharge voltage range was set to -0.5 V to 0.5 V, and the current density was set to 0.5 A / g. One charge / discharge cycle was considered as one cycle, and the number of cycles was 1000. The capacity retention rate was calculated using the formula: (C / C1)×100%, where C is the specific capacity after 1000 cycles and C1 is the initial specific capacity. The results are shown in Table 1.
[0029] Table 1 Analyzing the experimental data in Table 1, the specific capacity and cycle performance of the examples are superior to those of the comparative examples. This indicates that the present application prepared zinc and iron modified composite carbon nanofibers by using acetylacetone iron and zinc acetate as oxide precursors, and polyacrylonitrile, lignin, and pitch as carbon sources, combined with electrospinning and high-temperature carbonization processes. The iron in the composite carbon nanofibers is mainly ferric oxide and magnetite. When used as capacitor electrode materials, ferric oxide is beneficial for rapid electron transport, while magnetite promotes rapid electrolyte diffusion. The combination of the two can effectively reduce the charge transfer resistance and ion diffusion resistance during the electrochemical reaction process. The doping of iron oxides also endows the carbon nanofibers with certain redox activity, generating a pseudocapacitive effect, which makes them have higher specific capacity and cycle performance when used as capacitor electrode materials. Specific capacitance value; doping with amorphous zinc oxide provides more electrochemical active sites, and the surface redox reaction is induced by the rapid electrochemical adsorption / desorption of electrolyte, further improving the electrochemical performance of the capacitor electrode; thiophene and 3-aminomethylthiophene are polymerized and deposited on the surface of composite carbon nanofibers through oxidative polymerization to form a polythiophene coating layer, while amino groups are also introduced on the surface; polythiophene is a conductive polymer, and its combination with carbon nanofibers can further enhance the specific capacitance value of the composite material. The amino groups on the surface undergo Michael addition reaction with the α-β unsaturated carbon-carbon double bonds on poly(ethylene glycol) methacrylate, and a large number of hydrophilic polyethylene glycol structures are grafted onto the surface of functionalized composite carbon nanofibers, which enhances the wettability with electrolyte and further improves the electrochemical performance of the capacitor electrode.
[0030] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A high-capacity capacitor electrode material, characterized in that, The high-capacity capacitor electrode material is prepared by polymerizing and depositing thiophene and 3-aminomethylthiophene onto composite carbon nanofibers to obtain polythiophene-modified composite carbon nanofibers; reacting polythiophene-modified composite carbon nanofibers with poly(ethylene glycol) methacrylate to obtain functionalized composite carbon nanofibers; mixing and grinding functionalized composite carbon nanofibers, acetylene black, and adhesive to obtain a mixed slurry; coating the mixed slurry onto a nickel foam substrate; and drying to obtain the high-capacity capacitor electrode material.
2. The high-capacity capacitor electrode material as described in claim 1, characterized in that, The composite carbon nanofibers are obtained by high-temperature carbonization of composite fiber precursors.
3. The high-capacity capacitor electrode material as described in claim 2, characterized in that, The composite fiber precursor is obtained by electrospinning by uniformly mixing polyacrylonitrile, lignin, pitch, zinc acetate, and ferric acetylacetone to prepare a spinning solution.
4. A method for preparing a high-capacity capacitor electrode material, characterized in that, The method for preparing the high-capacity capacitor electrode material includes the following steps: S1: Mix asphalt and tetrahydrofuran at a mass ratio of 1:(5~6) to prepare an asphalt solution; add polyacrylonitrile and lignin to N,N-dimethylformamide at a mass ratio of 5~6 times that of lignin, stir at room temperature for 10~14h, add the asphalt solution, continue stirring for 20~30min, add zinc acetate and acetylacetone iron, stir at 35~45℃ for 3~5h to obtain a mixed spinning solution; place the spinning solution in an electrospinning device for electrospinning to obtain composite fiber precursor; S2: Place the composite fiber precursor in an electric furnace and heat it to 220~280℃ at a rate of 2℃ / min, and keep it at this temperature for 100~120min. Under nitrogen protection, heat it to 900~1000℃ at a rate of 5℃ / min, and keep it at this temperature for 60~70min. Cool it to room temperature to obtain composite carbon nanofibers. S3: Mix composite carbon nanofibers, ferric chloride, and chloroform in a mass ratio of 1:(0.04~0.06):(20~30) until homogeneous, sonicate for 30~40 min, add 16~20 times the mass of thiophene solution of composite carbon nanofibers under nitrogen protection, stir and react at room temperature for 20~24 h, filter, wash 3~5 times each with anhydrous ethanol and deionized water, and vacuum dry at 50~60℃ for 20~24 h to obtain polythiophene modified composite carbon nanofibers; S4: Polythiophene-modified composite carbon nanofibers and N,N-dimethylformamide are mixed evenly at a mass ratio of 1:(20~30), sonicated for 30~40 min, poly(ethylene glycol) methacrylate is added, stirred at 50~60℃ for 8~10 h, filtered, washed 3~5 times each with anhydrous ethanol and deionized water, and vacuum dried at 50~60℃ for 20~24 h to obtain functionalized composite carbon nanofibers; S5: Mix functionalized composite carbon nanofibers, acetylene black, and binder evenly, add N-methylpyrrolidone to control the solid content at 30%, grind for 1-2 hours to obtain a mixed slurry; coat the mixed slurry evenly on a nickel foam substrate, dry at 100-110℃ for 4-6 hours to obtain a high-capacity capacitor electrode material.
5. The method for preparing a high-capacity capacitor electrode material as described in claim 4, characterized in that, The dosage relationship of polyacrylonitrile, lignin, asphalt, zinc acetate, and ferric acetylacetone in step S1 is as follows: by mass parts, polyacrylonitrile 10-12 parts, lignin 20-30 parts, asphalt 6-8 parts, zinc acetate 1.8-2.2 parts, and ferric acetylacetone 1.3-1.5 parts.
6. The method for preparing a high-capacity capacitor electrode material as described in claim 4, characterized in that, The electrospinning process parameters in step S1 are set as follows: applied voltage is 22~26kV, feed rate is 1~1.2ml / h, collection rate is 400~600r / min, collection distance is 14~16cm, and vacuum drying is carried out at 60~70℃ for 10~12h.
7. The method for preparing a high-capacity capacitor electrode material as described in claim 4, characterized in that, The preparation method of the thiophene solution in step S3 is as follows: thiophene and 3-aminomethylthiophene are added to chloroform at a molar ratio of 1:(1.2~1.4) in 7~8 times the mass of thiophene, and mixed evenly to prepare a thiophene solution.
8. The method for preparing a high-capacity capacitor electrode material as described in claim 4, characterized in that, The average molecular weight of the poly(ethylene glycol) methacrylate described in step S4 is Mn=500.
9. The method for preparing a high-capacity capacitor electrode material as described in claim 4, characterized in that, The amount of poly(ethylene glycol) methacrylate added in step S4 is 2 to 2.2 times the mass of the polythiophene-modified composite carbon nanofibers.
10. The method for preparing a high-capacity capacitor electrode material as described in claim 4, characterized in that, The ratio of the amount of functionalized composite carbon nanofiber, acetylene black, and adhesive in step S5 is as follows: by mass parts, 78-82 parts of functionalized composite carbon nanofiber, 9-11 parts of acetylene black, and 9-11 parts of adhesive.