High-magnification supercapacitor film electrode material and preparation method thereof

Abstract

The invention discloses a high-magnification supercapacitor film electrode material and a preparation method thereof, and relates to the technical field of supercapacitors. The preparation method comprises the following steps: sequentially adding polyvinylpyrrolidone, modified graphene, composite nanofibers and an inhibiting solution into N, N-dimethylformamide, then carrying out ultrasonic dispersion, then adding polytetrafluoroethylene, and uniformly stirring to obtain mixed slurry; and coating the surface of the pretreated foamed nickel with the mixed slurry, then carrying out drying treatment, and then carrying out hot pressing treatment to obtain the high-magnification supercapacitor film electrode material. Wherein after the hot pressing treatment, the thickness of the mixed slurry on the surface of the high-magnification super capacitor thin film electrode material is 20-50 [mu] m. According to the preparation method, the capacitive performance and the rate capability of the electrode material are effectively improved through modification treatment on the graphene; and due to the introduction of components such as the composite nanofibers, the rate capability and the cycling stability of the material are further improved. Therefore, the capacitor has a wider application prospect.

Description

Technical Field

[0001] This invention relates to the field of supercapacitor technology, specifically to thin-film electrode materials for high-rate supercapacitors and their preparation methods. Background Technology

[0002] Supercapacitors are a novel type of energy storage device that bridges the gap between traditional capacitors and batteries, storing energy while also possessing rapid charge and discharge characteristics. A supercapacitor consists of electrodes, current collectors, an electrolyte, and a separator. Compared to various common energy storage devices, supercapacitors offer numerous advantages, including superior power density and cycle stability compared to secondary batteries, faster charge and discharge, storage capacity exceeding that of traditional dielectric capacitors, and greater environmental friendliness. Therefore, supercapacitors have become a candidate for new energy storage equipment and are widely researched and applied in fields such as new energy vehicles and mobile electronic devices. Despite these advantages, the low energy density of supercapacitors remains a critical issue. Therefore, the key challenge in developing supercapacitors is researching how to fabricate high-capacity electrode materials to improve their energy density and enable practical applications.

[0003] To address the aforementioned issues, transition metal carbon / nitride nanomaterials have attracted increasing attention due to their excellent hydrophilicity and conductivity, and have been widely studied and applied in supercapacitors. For example, patent document CN104916447A proposes a hierarchical porous carbon suitable for supercapacitor electrode materials and its preparation method. This method involves first preparing a zinc- and cobalt-containing zeolite imidazole compound, then carbonizing it at high temperature to obtain hierarchical porous carbon. This porous carbon contains numerous mesopores and micropores with hierarchical pore size distribution. This structure facilitates the transport of electrolyte ions and the formation of the electrical double layer within the porous carbon material. However, because transition metal carbon / nitride nanosheets are prone to stacking, and due to their large size and thin thickness, the electrolyte ion transport path is lengthy and slow, resulting in unsatisfactory capacitance and rate performance of the supercapacitor electrode material. Summary of the Invention

[0004] The purpose of this invention is to provide thin-film electrode materials for high-rate supercapacitors and their preparation methods, thereby solving the following technical problems: Existing supercapacitor electrode materials still suffer from unsatisfactory capacitance and rate performance.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing thin-film electrode materials for high-rate supercapacitors includes the following steps: Step S1: Polyvinylpyrrolidone, modified graphene, composite nanofibers and inhibitor are added sequentially to N,N-dimethylformamide, followed by ultrasonic dispersion for 30-45 min, then polytetrafluoroethylene is added and stirred evenly to obtain a mixed slurry; Step S2: Coat the mixed slurry onto the surface of the pretreated nickel foam, then dry it at 60-80℃ for 12-24h, and then perform hot pressing treatment at 120-150℃ and 5-10MPa for 10-20min to obtain the high-rate supercapacitor thin film electrode material; wherein, after hot pressing treatment, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material is 20-50μm.

[0006] Preferably, the ratio of N,N-dimethylformamide, polyvinylpyrrolidone, modified graphene, composite nanofibers, inhibitory liquid, and polytetrafluoroethylene in step S1 is 50-70mL: 0.1-0.25g: 0.2-0.5g: 0.8-1g: 10-14g: 0.1g.

[0007] Preferably, the modified graphene is prepared by the following method: Add 0.5-1g of graphene oxide to 100-150mL of deionized water and sonicate for 30-45min. Then adjust the pH to 9-11 with ammonia and react at 180-200℃ for 12-16h. After cooling to room temperature, obtain modified graphene through centrifugation, washing, and drying.

[0008] Preferably, the composite nanofibers are prepared as follows: Step A1: Add aniline to hydrochloric acid solution and stir evenly at 0-2℃ to obtain aniline hydrochloride solution; Step A2: Add ammonium persulfate to hydrochloric acid solution, stir for 30-45 min, and then slowly add it dropwise to aniline hydrochloride solution. React at 0-5℃ for 6-8 h, and then centrifuge, wash and dry to obtain polyaniline nanofibers. Step A3: Add manganese sulfate and potassium permanganate to deionized water, stir evenly, then add polyaniline nanofibers, stir and react for 12-24 hours, then centrifuge, wash and dry to obtain composite nanofibers.

[0009] Preferably, the concentration of the hydrochloric acid solution in step A1 is 1 mol / L; The ratio of hydrochloric acid solution to aniline in step A1 is 100 mL: 0.1-0.12 mol.

[0010] Preferably, the concentration of the hydrochloric acid solution in step A2 is 1 mol / L; The ratio of hydrochloric acid solution, ammonium persulfate and aniline hydrochloride solution used in step A2 is 50 mL: 0.11-0.13 mol: 100 mL.

[0011] Preferably, the ratio of deionized water, manganese sulfate, potassium permanganate, and polyaniline nanofibers in step A3 is 100-120 mL: 0.05 mol: 0.05 mol: 0.5 g.

[0012] Preferably, the method for preparing the inhibitory solution is as follows: Step B1: Mix black phosphorus olefin with lithium hydroxide monohydrate and ball mill for 12-15 hours. Then add deionized water and centrifuge for 30-40 minutes to obtain the sediment. Step B2: Add deionized water to the sediment and sonicate for 4-5 hours. Then centrifuge for 5-10 minutes and take the supernatant. Add hexadecyltrimethylammonium bromide and sonicate for 30-45 minutes to obtain the inhibition solution.

[0013] Preferably, the rotation speed during ball milling in step B1 is 250-300 rpm; The centrifugation speed described in step B1 is 7000-7500 rpm; The mass ratio of black phosphorus, lithium hydroxide monohydrate, and deionized water in step B1 is 0.3:0.7:150-200.

[0014] Preferably, the centrifugation speed in step B2 is 3500-4000 rpm; The mass ratio of the sediment, deionized water, supernatant, and cetyltrimethylammonium bromide in step B2 is 0.2-0.25:10-15:9-12:1.5-2.

[0015] The beneficial effects of this invention are: This invention provides a high-rate supercapacitor thin-film electrode material and its preparation method. The invention effectively improves the specific capacitance, rate performance and cycle stability of the supercapacitor thin-film electrode material through the following method.

[0016] (1) Graphene has abundant active sites and good conductivity, which can effectively improve the electron transport rate of electrode materials. At the same time, the doping of nitrogen atoms during the preparation of modified graphene changes the electronic structure of graphene, enhances the adsorption and storage capacity of ions in the electrolyte, thereby improving the specific capacitance, rate performance and cycle stability of the electrode material.

[0017] (2) Polyaniline has a high theoretical specific capacitance and good environmental stability, while manganese dioxide has a large specific surface area and abundant redox active sites. Composite nanofibers combine the advantages of both, providing more Faraday reaction active sites during high-rate charge and discharge processes, thereby improving the capacitance performance of the electrode material. At the same time, the conductivity of polyaniline helps to improve the electron transport efficiency of manganese dioxide, further improving the rate performance of the electrode material.

[0018] (3) The inhibitor can be adsorbed on the surface of active materials such as modified graphene and composite nanofibers, reducing the surface energy between particles and reducing particle agglomeration, thereby improving the consistency and stability of the final thin film electrode material performance; the components in the inhibitor will also have a certain effect at the interface between the electrode material and nickel foam, improving the wettability between the active material and nickel foam, enhancing the binding force between the active material and the current collector, reducing the possibility of the active material falling off the surface of the current collector during charging and discharging, and improving the structural stability and electron transport efficiency of the electrode; the addition of the deposit prepared by black phosphorus through ball milling, centrifugation and other treatments will further modify the surface properties of the deposit, enabling it to better cooperate with other active materials, thereby changing the surface charge distribution, promoting the adsorption and desorption process of ions in the electrolyte on the surface of the electrode material, and preventing the re-stacking of other components in the mixed slurry, thereby improving the capacitance and rate performance of the electrode material during high-rate charging and discharging.

[0019] (4) Hot pressing can make the active material and the current collector more tightly bonded, improve the mechanical properties and electronic transport properties of the electrode material, thereby improving the specific capacitance, rate performance and cycle stability of the high-rate supercapacitor thin film electrode material prepared by this invention.

[0020] Therefore, the high-rate supercapacitor thin-film electrode material prepared by this invention has superior specific capacitance, rate performance and cycle stability. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: The preparation method of thin-film electrode material for high-rate supercapacitors is as follows: S1: Add 0.5g of graphene oxide to 100mL of deionized water and sonicate for 30min. Then adjust the pH value to 9 with ammonia water and react at 180℃ for 12h. Cool to room temperature and obtain modified graphene through centrifugation, washing and drying. S2: Add 0.1 mol of aniline to 100 mL of 1 mol / L hydrochloric acid solution and stir at 0 °C to obtain aniline hydrochloride solution; S3: Add 0.11 mol of ammonium persulfate to 50 mL of 1 mol / L hydrochloric acid solution, stir for 30 min, and then slowly add it dropwise to 100 mL of aniline hydrochloride solution. React at 0℃ for 6 h, and then centrifuge, wash and dry to obtain polyaniline nanofibers. S4: Add 0.05 mol manganese sulfate and 0.05 mol potassium permanganate to 100 mL of deionized water, stir evenly, then add 0.5 g of polyaniline nanofibers, stir and react for 12 h, then centrifuge, wash and dry to obtain composite nanofibers. S5: Mix 0.3g black phosphorus olefin with 0.7g lithium hydroxide monohydrate and ball mill at 250rpm for 12h. Then add 150mL deionized water and centrifuge at 7000rpm for 30min to obtain the sediment. S6: Add 10 mL of deionized water to 0.2 g of sediment and sonicate for 4 h. Then centrifuge at 3500 rpm for 5 min and take the supernatant. Add 1.5 g of cetyltrimethylammonium bromide and sonicate for 30 min to obtain the inhibition solution. S7: Add 0.1g polyvinylpyrrolidone, 0.2g modified graphene, 0.8g composite nanofibers and 10g inhibitor to 50mL of N,N-dimethylformamide in sequence, then ultrasonically disperse for 30min, then add 0.1g polytetrafluoroethylene and stir evenly to obtain a mixed slurry; S8: Cut the nickel foam into 1cm×1.5cm pieces, then sonicate them in acetone for 15min, then sonicate them in anhydrous ethanol for 15min, and finally dry them at 40℃ to obtain pretreated nickel foam. S9: The mixed slurry is coated on the surface of pretreated nickel foam, then dried at 60°C for 12 hours, and then hot-pressed at 120°C and 5MPa for 10 minutes to obtain the high-rate supercapacitor thin film electrode material; wherein, after hot pressing, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material is 20μm.

[0023] Example 2: The preparation method of thin-film electrode material for high-rate supercapacitors is as follows: S1: Add 0.8g of graphene oxide to 130mL of deionized water and sonicate for 35min. Then adjust the pH to 10 with ammonia and react at 190℃ for 14h. Cool to room temperature and obtain modified graphene through centrifugation, washing and drying. S2: Add 0.11 mol of aniline to 100 mL of 1 mol / L hydrochloric acid solution and stir at 1 °C to obtain aniline hydrochloride solution; S3: Add 0.12 mol of ammonium persulfate to 50 mL of 1 mol / L hydrochloric acid solution, stir for 35 min, and then slowly add it dropwise to 100 mL of aniline hydrochloride solution. React at 3℃ for 7 h, and then centrifuge, wash and dry to obtain polyaniline nanofibers. S4: Add 0.05 mol manganese sulfate and 0.05 mol potassium permanganate to 110 mL of deionized water, stir evenly, then add 0.5 g of polyaniline nanofibers, stir and react for 18 h, then centrifuge, wash and dry to obtain composite nanofibers. S5: Mix 0.3g black phosphorus olefin with 0.7g lithium hydroxide monohydrate and ball mill at 280rpm for 14h. Then add 180mL deionized water and centrifuge at 7300rpm for 35min to obtain the sediment. S6: Add 13 mL of deionized water to 0.23 g of sediment and sonicate for 4.5 h. Then centrifuge at 3800 rpm for 8 min and take the supernatant. Add 1.8 g of cetyltrimethylammonium bromide and sonicate for 35 min to obtain the inhibition solution. S7: Add 0.15g polyvinylpyrrolidone, 0.3g modified graphene, 0.9g composite nanofibers and 12g inhibitor to 60mL of N,N-dimethylformamide in sequence, then ultrasonically disperse for 35min, then add 0.1g polytetrafluoroethylene and stir evenly to obtain a mixed slurry. S8: Cut the nickel foam into 1cm×1.5cm pieces, then sonicate them in acetone for 20min, then sonicate them in anhydrous ethanol for 20min, and finally dry them at 50℃ to obtain pretreated nickel foam. S9: The mixed slurry is coated on the surface of pretreated nickel foam, then dried at 70°C for 18 hours, and then hot-pressed at 130°C and 8MPa for 15 minutes to obtain the high-rate supercapacitor thin film electrode material; wherein, after hot pressing, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material is 35μm.

[0024] Example 3: The preparation method of thin-film electrode material for high-rate supercapacitors is as follows: S1: Add 1g of graphene oxide to 150mL of deionized water and sonicate for 45min. Then adjust the pH value to 11 with ammonia water and react at 200℃ for 16h. Cool to room temperature and obtain modified graphene through centrifugation, washing and drying. S2: Add 0.12 mol of aniline to 100 mL of 1 mol / L hydrochloric acid solution and stir at 2 °C to obtain aniline hydrochloride solution; S3: Add 0.13 mol of ammonium persulfate to 50 mL of 1 mol / L hydrochloric acid solution, stir for 45 min, and then slowly add it dropwise to 100 mL of aniline hydrochloride solution. React at 5 °C for 8 h, and then centrifuge, wash and dry to obtain polyaniline nanofibers. S4: Add 0.05 mol manganese sulfate and 0.05 mol potassium permanganate to 120 mL of deionized water, stir evenly, then add 0.5 g of polyaniline nanofibers, stir and react for 24 h, then centrifuge, wash and dry to obtain composite nanofibers. S5: Mix 0.3g black phosphorus olefin with 0.7g lithium hydroxide monohydrate and ball mill at 300rpm for 12-15h. Then add 200mL deionized water and centrifuge at 7500rpm for 40min to obtain the sediment. S6: Add 15 mL of deionized water to 0.25 g of sediment and sonicate for 5 h. Then centrifuge at 4000 rpm for 10 min and take the supernatant. Add 2 g of hexadecyltrimethylammonium bromide and sonicate for 45 min to obtain the inhibition solution. S7: Add 0.25g polyvinylpyrrolidone, 0.5g modified graphene, 1g composite nanofiber and 14g inhibitor to 70mL of N,N-dimethylformamide in sequence, then ultrasonically disperse for 45min, then add 0.1g polytetrafluoroethylene and stir evenly to obtain a mixed slurry. S8: Cut the nickel foam into 1cm×1.5cm pieces, then sonicate it in acetone for 30min, then sonicate it in anhydrous ethanol for 30min, and finally dry it at 60℃ to obtain pretreated nickel foam. S9: The mixed slurry is coated on the surface of pretreated nickel foam, then dried at 80°C for 24 hours, and then hot-pressed at 150°C and 10MPa for 20 minutes to obtain the high-rate supercapacitor thin film electrode material; wherein, after hot-pressing, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material is 50μm.

[0025] Comparative Example 1: Compared with Example 1, this comparative example only replaces the "modified graphene" added during the preparation of the mixed slurry with "graphene oxide". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a high-rate supercapacitor thin film electrode material is obtained.

[0026] Comparative Example 2: Compared with Example 1, this comparative example only replaces the "modified graphene" added during the preparation of the mixed slurry with the "composite nanofibers" prepared in step S4. All other steps and parameters are the same, and will not be repeated here. The final result is a high-rate supercapacitor thin film electrode material.

[0027] Comparative Example 3: Compared with Example 1, this comparative example only replaces the "composite nanofibers" added during the preparation of the mixed slurry with the "modified graphene" prepared in step S1. All other steps and parameters are the same, and will not be repeated here. The final result is a high-rate supercapacitor thin film electrode material.

[0028] Comparative Example 4: Compared with Example 1, this comparative example only replaces the "10g inhibitor" added during the preparation of the mixed slurry with "the dispersion obtained by adding 1.5g hexadecyltrimethylammonium bromide to 8.5mL of deionized water and ultrasonically dispersing for 30min". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a high-rate supercapacitor thin film electrode material is obtained.

[0029] Comparative Example 5: Compared with Example 1, this comparative example only omits the hot-pressing treatment during the preparation of the high-rate supercapacitor thin film electrode material. All other steps and parameters are the same, and will not be repeated here. The final result is a high-rate supercapacitor thin film electrode material.

[0030] Performance testing: Specific capacity test: A three-electrode system was used, with the prepared thin-film electrode material as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet as the counter electrode. The specific capacitance of the electrode material was tested in a 1 mol / L sulfuric acid electrolyte using cyclic voltammetry and constant current charge-discharge method. The specific capacitance of the high-rate supercapacitor thin-film electrode materials prepared in Examples 1-3 and proportions 1-5 was determined at a current density of 1 A / g according to the above method; the test results are shown in Table 1.

[0031] Determination of rate performance (specific capacity retention): A three-electrode system was used, with the prepared thin-film electrode material as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet as the counter electrode. The specific capacitance of the electrode material was tested in a 1 mol / L sulfuric acid electrolyte using cyclic voltammetry and constant current charge-discharge methods. The specific capacitance of the high-rate supercapacitor thin-film electrode materials prepared in Examples 1-3 and Ratios 1-5 was determined at a current density of 10 A / g according to the above method, and the capacitance retention rate (equivalent to the specific capacitance at a current density of 1 A / g) was calculated as the rate performance of the thin-film electrode material. The test results are shown in Table 1.

[0032] Determination of cyclic stability: A three-electrode system was used, with the prepared thin-film electrode material as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet as the counter electrode. The specific capacitance of the electrode material was tested in a 1 mol / L sulfuric acid electrolyte using cyclic voltammetry and constant current charge-discharge methods. The specific capacitance of the high-rate supercapacitor thin-film electrode materials prepared in Examples 1-3 and Ratios 1-5 was determined at a current density of 10 A / g and after 10,000 cycles at a current density of 10 A / g, following the above method. The capacitance retention rate after cycling was calculated as the cyclic stability of the thin-film electrode material. The test results are shown in Table 1.

[0033] Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-5

[0034] Data Analysis: As can be seen from Table 1, the high-rate supercapacitor thin-film electrode material prepared by this invention has superior specific capacitance, rate performance and cycle stability.

[0035] This may be due to: (1) Graphene has abundant active sites and good conductivity, which can effectively improve the electron transport rate of electrode materials. At the same time, the doping of nitrogen atoms during the preparation of modified graphene changes the electronic structure of graphene, enhances the adsorption and storage capacity of ions in the electrolyte, thereby improving the specific capacitance, rate performance and cycle stability of the electrode material.

[0036] (2) Polyaniline has a high theoretical specific capacitance and good environmental stability, while manganese dioxide has a large specific surface area and abundant redox active sites. Composite nanofibers combine the advantages of both, providing more Faraday reaction active sites during high-rate charge and discharge processes, thereby improving the capacitance performance of the electrode material. At the same time, the conductivity of polyaniline helps to improve the electron transport efficiency of manganese dioxide, further improving the rate performance of the electrode material.

[0037] (3) The inhibitor can be adsorbed on the surface of active materials such as modified graphene and composite nanofibers, reducing the surface energy between particles and reducing particle agglomeration, thereby improving the consistency and stability of the final thin film electrode material performance; the components in the inhibitor will also have a certain effect at the interface between the electrode material and nickel foam, improving the wettability between the active material and nickel foam, enhancing the binding force between the active material and the current collector, reducing the possibility of the active material falling off the surface of the current collector during charging and discharging, and improving the structural stability and electron transport efficiency of the electrode; the addition of the deposit prepared by black phosphorus through ball milling, centrifugation and other treatments will further modify the surface properties of the deposit, enabling it to better cooperate with other active materials, thereby changing the surface charge distribution, promoting the adsorption and desorption process of ions in the electrolyte on the surface of the electrode material, and preventing the re-accumulation of other components in the mixed slurry, thereby improving the capacitance and rate performance of the electrode material during high-rate charging and discharging.

[0038] (4) Hot pressing can make the active material and the current collector more tightly bonded, improve the mechanical properties and electronic transport properties of the electrode material, thereby improving the specific capacitance, rate performance and cycle stability of the high-rate supercapacitor thin film electrode material prepared by this invention.

[0039] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing thin-film electrode materials for high-rate supercapacitors, characterized in that, Includes the following steps: Step S1: Polyvinylpyrrolidone, modified graphene, composite nanofibers and inhibitor are added sequentially to N,N-dimethylformamide, followed by ultrasonic dispersion for 30-45 min, then polytetrafluoroethylene is added and stirred evenly to obtain a mixed slurry; Step S2: Coat the mixed slurry onto the surface of the pretreated nickel foam, then dry it at 60-80℃ for 12-24h, and then perform hot pressing treatment at 120-150℃ and 5-10MPa for 10-20min to obtain the high-rate supercapacitor thin film electrode material; wherein, after hot pressing treatment, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material is 20-50μm.

2. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, characterized in that, The ratio of N,N-dimethylformamide, polyvinylpyrrolidone, modified graphene, composite nanofibers, inhibitory liquid, and polytetrafluoroethylene used in step S1 is 50-70mL: 0.1-0.25g: 0.2-0.5g: 0.8-1g: 10-14g: 0.1g.

3. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, characterized in that, The modified graphene is prepared as follows: Add 0.5-1g of graphene oxide to 100-150mL of deionized water and sonicate for 30-45min. Then adjust the pH to 9-11 with ammonia and react at 180-200℃ for 12-16h. After cooling to room temperature, obtain modified graphene through centrifugation, washing, and drying.

4. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, characterized in that, The preparation method of the composite nanofibers is as follows: Step A1: Add aniline to hydrochloric acid solution and stir evenly at 0-2℃ to obtain aniline hydrochloride solution; Step A2: Add ammonium persulfate to hydrochloric acid solution, stir for 30-45 min, and then slowly add it dropwise to aniline hydrochloride solution. React at 0-5℃ for 6-8 h, and then centrifuge, wash and dry to obtain polyaniline nanofibers. Step A3: Add manganese sulfate and potassium permanganate to deionized water, stir evenly, then add polyaniline nanofibers, stir and react for 12-24 hours, then centrifuge, wash and dry to obtain composite nanofibers.

5. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 4, characterized in that, The concentration of the hydrochloric acid solution mentioned in step A1 is 1 mol / L; The ratio of hydrochloric acid solution to aniline used in step A1 is 100 mL: 0.1-0.12 mol.

6. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 4, characterized in that, The concentration of the hydrochloric acid solution mentioned in step A2 is 1 mol / L; The ratio of hydrochloric acid solution, ammonium persulfate and aniline hydrochloride solution used in step A2 is 50 mL: 0.11-0.13 mol: 100 mL.

7. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 4, characterized in that, The ratio of deionized water, manganese sulfate, potassium permanganate, and polyaniline nanofibers used in step A3 is 100-120 mL: 0.05 mol: 0.05 mol: 0.5 g.

8. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, characterized in that, The method for preparing the inhibitory solution is as follows: Step B1: Mix black phosphorus olefin with lithium hydroxide monohydrate and ball mill for 12-15 hours. Then add deionized water and centrifuge for 30-40 minutes to obtain the sediment. Step B2: Add deionized water to the sediment and sonicate for 4-5 hours. Then centrifuge for 5-10 minutes and take the supernatant. Add hexadecyltrimethylammonium bromide and sonicate for 30-45 minutes to obtain the inhibition solution.

9. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 8, characterized in that, The rotational speed during ball milling in step B1 is 250-300 rpm; The centrifugation speed described in step B1 is 7000-7500 rpm; The mass ratio of black phosphorus, lithium hydroxide monohydrate, and deionized water in step B1 is 0.3:0.7:150-200.

10. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 8, characterized in that, The centrifugation speed described in step B2 is 3500-4000 rpm; The mass ratio of the sediment, deionized water, and hexadecyltrimethylammonium bromide in step B2 is 0.2-0.25:10-15:1.5-2.

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