High-rate supercapacitor thin film electrode material and preparation method thereof

Abstract

The application discloses a high-rate supercapacitor thin film electrode material and a preparation method thereof, and relates to the technical field of supercapacitors. The application comprises the following steps: sequentially adding polyvinylpyrrolidone, modified graphene, composite nanofibers and an inhibiting liquid into N,N-dimethylformamide, then performing ultrasonic dispersion, adding polytetrafluoroethylene and uniformly stirring to obtain a mixed slurry; coating the mixed slurry on the surface of pretreated foamed nickel, then performing drying treatment, and finally performing hot-pressing treatment to obtain the high-rate supercapacitor thin film electrode material; wherein, after the hot-pressing treatment, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material is 20-50 mu m. The modification treatment of graphene effectively improves the capacitance performance and rate performance of the electrode material; the introduction of the composite nanofibers and other components further improves the rate performance and cycle stability. Therefore, the capacitor has a more extensive application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of supercapacitors, in particular to a high-rate supercapacitor thin film electrode material and a preparation method thereof. BACKGROUND

[0002] A supercapacitor is a new type of energy storage device, which can make up for the gap between traditional capacitors and batteries, and has the characteristics of fast charging and discharging while storing energy. The supercapacitor is composed of an electrode, a current collector, an electrolyte and a separator. Compared with various types of current energy storage devices, the supercapacitor has many advantages over secondary batteries, such as higher power density and cycle stability, faster charging and discharging, more energy storage than traditional dielectric capacitors, and more environmental friendliness. Therefore, the supercapacitor becomes a candidate for new energy storage equipment and is widely researched and applied in the fields of new energy vehicles and mobile electronic devices. Although the supercapacitor has many advantages, the key problem of low energy density cannot be ignored. Therefore, the key problem of developing the supercapacitor at present is to study how to prepare an electrode material with high capacity, so as to improve the energy density of the supercapacitor and realize the practical application of the supercapacitor.

[0003] In order to solve the above problems, transition metal carbon / nitride in two-dimensional nanomaterials has attracted more and more attention due to its excellent hydrophilicity and conductivity, and is widely researched and applied in supercapacitors. For example, patent technical document CN104916447A proposes a hierarchical porous carbon suitable for being used as a supercapacitor electrode material and a preparation method thereof. The hierarchical porous carbon preparation method is characterized in that: firstly, a zinc and cobalt-containing zeolite imidazole compound is prepared, and then the zeolite imidazole compound is subjected to carbonization treatment at high temperature to obtain the hierarchical porous carbon. A large number of mesopores and micropores exist in the porous carbon, and the pore size is distributed in stages. The formation of this structure is beneficial to the transmission of electrolyte ions in the porous carbon material and the formation of a double electric layer. However, due to the fact that transition metal carbon / nitride nanosheets are very easy to stack, and the size is large and the thickness is thin, the electrolyte ion transmission path is long, and the ion transmission is slow, so that the capacitance performance and rate performance of the supercapacitor electrode material are still not ideal. SUMMARY

[0004] The purpose of the present application is to provide a high-rate supercapacitor thin film electrode material and a preparation method thereof, and to solve the following technical problems:

[0005] The existing supercapacitor electrode material still has the problem of unsatisfactory capacitance performance and rate performance.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] The preparation method of the high-rate supercapacitor thin film electrode material comprises the following steps:

[0008] Step S1: sequentially adding polyvinylpyrrolidone, modified graphene, composite nanofiber and inhibitor solution in N,N-dimethylformamide, then ultrasonic dispersion for 30-45 min, and then adding polytetrafluoroethylene and stirring uniformly to obtain a mixed slurry;

[0009] Step S2: coating the mixed slurry on the surface of the pretreated nickel foam, then drying at 60-80℃ for 12-24 h, and then performing hot pressing treatment at 120-150℃ and 5-10 MPa for 10-20 min to obtain a high-rate supercapacitor thin film electrode material; wherein the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material after the hot pressing treatment is 20-50 μm.

[0010] Preferably, the amount ratio of N,N-dimethylformamide, polyvinylpyrrolidone, modified graphene, composite nanofiber, inhibitor solution and polytetrafluoroethylene in step S1 is 50-70 mL: 0.1-0.25 g: 0.2-0.5 g: 0.8-1 g: 10-14 g: 0.1 g.

[0011] Preferably, the preparation method of the modified graphene is as follows:

[0012] adding 0.5-1 g of graphene oxide in 100-150 mL of deionized water and ultrasonic treatment for 30-45 min, then adjusting the pH value to 9-11 with ammonia water, and then reacting at 180-200℃ for 12-16 h, and then cooling to room temperature, and then performing centrifugation, washing and drying to obtain the modified graphene.

[0013] Preferably, the preparation method of the composite nanofiber is as follows:

[0014] Step A1: adding aniline in hydrochloric acid solution and stirring uniformly at 0-2℃ to obtain an aniline hydrochloride solution;

[0015] Step A2: adding ammonium persulfate in the hydrochloric acid solution, slowly adding to the aniline hydrochloride solution after stirring for 30-45 min, reacting at 0-5℃ for 6-8 h, and then performing centrifugation, washing and drying to obtain polyaniline nanofiber;

[0016] Step A3: adding manganese sulfate and potassium permanganate in deionized water, stirring uniformly, and then adding the polyaniline nanofiber, and then stirring and reacting for 12-24 h, and then performing centrifugation, washing and drying to obtain the composite nanofiber.

[0017] Preferably, the concentration of the hydrochloric acid solution in step A1 is 1 mol / L.

[0018] The amount ratio of the hydrochloric acid solution and aniline in step A1 is 100 mL: 0.1-0.12 mol.

[0019] Preferably, the concentration of the hydrochloric acid solution in step A2 is 1 mol / L.

[0020] The amount ratio of the hydrochloric acid solution, ammonium persulfate, aniline hydrochloride solution in step A2 is 50 mL:0.11-0.13 mol:100 mL.

[0021] Preferably, the amount ratio of the deionized water, manganese sulfate, potassium permanganate, polyaniline nanofiber in step A3 is 100-120 mL:0.05 mol:0.05 mol:0.5 g.

[0022] Preferably, the preparation method of the inhibiting solution is as follows:

[0023] Step B1: black phosphorus is mixed with lithium hydroxide monohydrate and then subjected to 12-15h ball milling treatment, followed by adding deionized water and performing 30-40min centrifugal treatment to obtain a deposit;

[0024] Step B2: deionized water is added to the deposit and subjected to ultrasonic stirring for 4-5h, followed by 5-10min centrifugal treatment and taking the supernatant, and then cetyltrimethylammonium bromide is added and subjected to 30-45min ultrasonic dispersion to obtain an inhibiting solution.

[0025] Preferably, the rotating speed during the ball milling treatment in step B1 is 250-300 rpm;

[0026] The rotating speed during the centrifugal treatment in step B1 is 7000-7500 rpm;

[0027] The mass ratio of the black phosphorus, lithium hydroxide monohydrate, deionized water in step B1 is 0.3:0.7:150-200.

[0028] Preferably, the rotating speed during the centrifugal treatment in step B2 is 3500-4000 rpm;

[0029] The mass ratio of the deposit, deionized water, supernatant, cetyltrimethylammonium bromide in step B2 is 0.2-0.25:10-15:9-12:1.5-2.

[0030] The beneficial effects of the present application are as follows:

[0031] The present application provides a high-rate supercapacitor thin film electrode material and a preparation method thereof, and effectively improves the specific capacitance, rate performance and cycle stability of the supercapacitor thin film electrode material through the following method.

[0032] (1) Graphene has abundant active sites and good electrical conductivity, which can effectively improve the electron transmission rate of the electrode material. At the same time, the nitrogen atoms doped in the preparation process of modified graphene change the electronic structure of graphene, enhance the adsorption and storage capacity of ions in the electrolyte, and thus improve the specific capacitance, rate performance and cycle stability of the electrode material.

[0033] (2) Polyaniline has high theoretical specific capacitance and good environmental stability, and manganese dioxide has large specific surface area and abundant redox active sites. The composite nanofiber combines the advantages of both, can provide more faradic reaction active sites during high-rate charging and discharging process, and improve the capacitance performance of the electrode material. At the same time, the electrical conductivity of polyaniline helps to improve the electron transmission efficiency of manganese dioxide, further improving the rate performance of the electrode material.

[0034] (3) The inhibiting liquid can be adsorbed on the surface of active materials such as modified graphene and composite nanofiber, reducing the surface energy between particles and reducing particle agglomeration, thereby improving the consistency and stability of the performance of the finally prepared thin film electrode material; the components in the inhibiting liquid also have certain effects at the interface between the electrode material and the foam nickel, improving the wettability between the active material and the foam nickel, enhancing the adhesion between the active material and the current collector, reducing the possibility of active material falling off from the surface of the current collector during charging and discharging, improving the structural stability and electron transmission efficiency of the electrode; the addition of the sediment prepared by ball milling, centrifugation and other treatments of black phosphorus can further modify the surface properties of the sediment, so that it can better synergize 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 at the same time preventing the re-stacking of other components in the mixed slurry, improving the capacitance performance and rate performance of the electrode material during high-rate charging and discharging.

[0035] (4) The heat pressing treatment can make the combination between the active material and the current collector more closely, improve the mechanical properties and electron transmission 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 the present application.

[0036] Therefore, the high-rate supercapacitor thin film electrode material prepared by the present application has more excellent specific capacitance, rate performance and cycle stability. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0038] Example 1: Preparation method of high-rate supercapacitor thin film electrode material as follows:

[0039] S1: 0.5 g of graphene oxide was added to 100 mL of deionized water and ultrasonically treated for 30 min, then the pH value was adjusted to 9 with ammonia water, and then reacted at 180°C for 12 h, cooled to room temperature, and then obtained by centrifugation, washing, drying and other steps to obtain modified graphene;

[0040] S2: 0.1 mol of aniline was added to 100 mL of 1 mol / L hydrochloric acid solution, and stirred uniformly at 0°C to obtain aniline hydrochloride solution;

[0041] S3: 0.11 mol of ammonium persulfate was added to 50 mL of 1 mol / L hydrochloric acid solution, and after stirring for 30 min, it was slowly added to 100 mL of aniline hydrochloride solution, and reacted at 0°C for 6 h, and then treated by centrifugation, washing and drying to obtain polyaniline nanofiber;

[0042] S4: 0.05 mol of manganese sulfate and 0.05 mol of potassium permanganate were added to 100 mL of deionized water, and after stirring uniformly, 0.5 g of polyaniline nanofiber was added, and then stirred and reacted for 12 h, and then treated by centrifugation, washing and drying to obtain composite nanofiber;

[0043] S5: 0.3 g of black phosphorene was mixed with 0.7 g of lithium hydroxide monohydrate, and then ball-milled at a speed of 250 rpm for 12 h, then 150 mL of deionized water was added and centrifuged at a speed of 7000 rpm for 30 min to obtain a precipitate;

[0044] S6: 10 mL of deionized water was added to 0.2 g of the precipitate and ultrasonically stirred for 4 h, then centrifuged at 3500 rpm for 5 min and the supernatant was taken, then 1.5 g of cetyltrimethylammonium bromide was added and ultrasonically dispersed for 30 min to obtain an inhibition solution;

[0045] S7: 0.1 g of polyvinylpyrrolidone, 0.2 g of modified graphene, 0.8 g of composite nanofiber and 10 g of inhibition solution were added to 50 mL of N,N-dimethylformamide in sequence, and then ultrasonically dispersed for 30 min, and then 0.1 g of polytetrafluoroethylene was added and stirred uniformly to obtain a mixed slurry;

[0046] S8: The foamed nickel was cut into 1 cm x 1.5 cm, and then ultrasonically treated in acetone for 15 min, and then ultrasonically treated in anhydrous ethanol for 15 min, and finally dried at 40°C to obtain pretreated foamed nickel;

[0047] S9: The mixed slurry is coated on the pretreated foam nickel surface, and then dried at 60°C for 12h, and then hot-pressed at 120°C and 5MPa for 10min to obtain a high-rate supercapacitor thin film electrode material; wherein the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material after hot pressing is 20μm.

[0048] Example 2: The preparation method of the high-rate supercapacitor thin film electrode material is as follows:

[0049] S1: 0.8g of graphene oxide is added to 130mL of deionized water and ultrasonically treated for 35min, and then the pH value is adjusted to 10 with ammonia water, and then reacted at 190°C for 14h, cooled to room temperature, and then treated by centrifugation, washing, drying and the like to obtain modified graphene;

[0050] S2: 0.11mol of aniline is added to 100mL of a hydrochloric acid solution with a concentration of 1mol / L, and stirred uniformly at 1°C to obtain an aniline hydrochloride solution;

[0051] S3: 0.12mol of ammonium persulfate is added to 50mL of a hydrochloric acid solution with a concentration of 1mol / L, and after stirring for 35min, it is slowly added dropwise to 100mL of the aniline hydrochloride solution, and reacted at 3°C for 7h, and then treated by centrifugation, washing, drying and the like to obtain polyaniline nanofibers;

[0052] S4: 0.05mol of manganese sulfate and 0.05mol of potassium permanganate are added to 110mL of deionized water, and after stirring uniformly, 0.5g of polyaniline nanofibers is added, and then stirred and reacted for 18h, and then treated by centrifugation, washing, drying and the like to obtain composite nanofibers;

[0053] S5: 0.3g of black phosphorene is mixed with 0.7g of lithium hydroxide monohydrate, and then ball-milled at a speed of 280rpm for 14h, and then 180mL of deionized water is added and centrifuged at a speed of 7300rpm for 35min to obtain a precipitate;

[0054] S6: 13mL of deionized water is added to 0.23g of the precipitate and ultrasonically stirred for 4.5h, and then centrifuged at 3800rpm for 8min and the supernatant is taken, and then 1.8g of cetyltrimethylammonium bromide is added and ultrasonically dispersed for 35min to obtain an inhibition solution;

[0055] S7: 0.15g of polyvinylpyrrolidone, 0.3g of modified graphene, 0.9g of composite nanofibers and 12g of the inhibition solution are sequentially added to 60mL of N,N-dimethylformamide, and then ultrasonically dispersed for 35min, and then 0.1g of polytetrafluoroethylene is added and stirred uniformly to obtain a mixed slurry;

[0056] S8: The foamed nickel was cut into 1 cm x 1.5 cm, and then was ultrasonically treated in acetone for 20 min, and then was ultrasonically treated in anhydrous ethanol for 20 min, and finally was dried at 50°C to obtain the pretreated foamed nickel;

[0057] S9: The mixed slurry was coated on the surface of the pretreated foamed nickel, and then was dried at 70°C for 18 h, and then was hot-pressed at 130°C and 8 MPa for 15 min to obtain the high-rate supercapacitor thin film electrode material; wherein after the hot-pressing treatment, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material was 35 μm.

[0058] Example 3: The preparation method of the high-rate supercapacitor thin film electrode material was as follows:

[0059] S1: 1 g of graphene oxide was added to 150 mL of deionized water and ultrasonically treated for 45 min, and then the pH value was adjusted to 11 with ammonia water, and then was reacted at 200°C for 16 h, and then was cooled to room temperature, and then was treated by centrifugation, washing, and drying to obtain the modified graphene;

[0060] S2: 0.12 mol of aniline was added to 100 mL of a hydrochloric acid solution with a concentration of 1 mol / L, and was stirred uniformly at 2°C to obtain an aniline hydrochloride solution;

[0061] S3: 0.13 mol of ammonium persulfate was added to 50 mL of a hydrochloric acid solution with a concentration of 1 mol / L, and was stirred for 45 min, and then was slowly added dropwise to 100 mL of the aniline hydrochloride solution, and was reacted at 5°C for 8 h, and then was treated by centrifugation, washing, and drying to obtain polyaniline nanofibers;

[0062] S4: 0.05 mol of manganese sulfate and 0.05 mol of potassium permanganate were added to 120 mL of deionized water, and were stirred uniformly, and then 0.5 g of the polyaniline nanofibers was added, and then was stirred and reacted for 24 h, and then was treated by centrifugation, washing, and drying to obtain the composite nanofibers;

[0063] S5: 0.3 g of black phosphorene was mixed with 0.7 g of lithium hydroxide monohydrate, and was subjected to ball milling at a speed of 300 rpm for 12-15 h, and then 200 mL of deionized water was added and was subjected to centrifugation at a speed of 7500 rpm for 40 min to obtain a precipitate;

[0064] S6: 15 mL of deionized water was added to 0.25 g of the precipitate and was ultrasonically stirred for 5 h, and then was centrifuged at 4000 rpm for 10 min and the supernatant was taken, and then 2 g of cetyltrimethylammonium bromide was added and was ultrasonically dispersed for 45 min to obtain an inhibition solution;

[0065] S7: 0.25 g of polyvinylpyrrolidone, 0.5 g of modified graphene, 1 g of composite nanofiber and 14 g of inhibition solution were sequentially added in 70 mL of N,N-dimethylformamide, and then ultrasonic dispersion was performed for 45 min, 0.1 g of polytetrafluoroethylene was added and stirred uniformly to obtain a mixed slurry;

[0066] S8: The foamed nickel was cut into 1 cm x 1.5 cm, and then ultrasonic treatment was performed in acetone for 30 min, ultrasonic treatment was performed in anhydrous ethanol for 30 min, and finally drying was performed at 60°C to obtain pretreated foamed nickel;

[0067] S9: The mixed slurry was coated on the surface of the pretreated foamed nickel, and then drying was performed at 80°C for 24 h, and hot pressing treatment was performed at 150°C and 10 MPa for 20 min to obtain a high-rate supercapacitor thin film electrode material; wherein after the hot pressing treatment, the thickness of the mixed slurry on the surface of the high-rate supercapacitor thin film electrode material was 50 μm.

[0068] Comparative Example 1:

[0069] This comparative example only replaces the "modified graphene" added in the preparation process of the mixed slurry with "graphene oxide" compared with Example 1, and the rest of the steps and parameters are the same, which will not be repeated here. Finally, a high-rate supercapacitor thin film electrode material is obtained.

[0070] Comparative Example 2:

[0071] This comparative example only replaces the "modified graphene" added in the preparation process of the mixed slurry with "composite nanofiber" prepared in step S4 compared with Example 1, and the rest of the steps and parameters are the same, which will not be repeated here. Finally, a high-rate supercapacitor thin film electrode material is obtained.

[0072] Comparative Example 3:

[0073] This comparative example only replaces the "composite nanofiber" added in the preparation process of the mixed slurry with "modified graphene" prepared in step S1 compared with Example 1, and the rest of the steps and parameters are the same, which will not be repeated here. Finally, a high-rate supercapacitor thin film electrode material is obtained.

[0074] Comparative Example 4:

[0075] This comparative example only replaces the "10 g of inhibition solution" added in the preparation process of the mixed slurry with "a dispersion solution obtained by adding 1.5 g of cetyltrimethylammonium bromide in 8.5 mL of deionized water and performing ultrasonic dispersion for 30 min" compared with Example 1, and the rest of the steps and parameters are the same, which will not be repeated here. Finally, a high-rate supercapacitor thin film electrode material is obtained.

[0076] Comparative Example 5:

[0077] The comparative example is compared with example 1 only without heat pressing treatment in the preparation process of the high-rate supercapacitor thin film electrode material, and the rest of the steps and parameters are the same. The comparative example will not be repeated. The high-rate supercapacitor thin film electrode material is finally obtained.

[0078] Performance detection:

[0079] Specific capacity test:

[0080] 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 capacity of the electrode material was tested by cyclic voltammetry and constant current charge-discharge method in 1 mol / L sulfuric acid electrolyte. The specific capacity of the high-rate supercapacitor thin film electrode material prepared in examples 1-3 and comparative examples 1-5 was measured at a current density of 1 A / g according to the above method; the test results are shown in Table 1.

[0081] Rate performance (specific capacity retention rate) test:

[0082] 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 capacity of the electrode material was tested by cyclic voltammetry and constant current charge-discharge method in 1 mol / L sulfuric acid electrolyte. The specific capacity of the high-rate supercapacitor thin film electrode material prepared in examples 1-3 and comparative examples 1-5 was measured at a current density of 10 A / g, and the specific capacity retention rate (equivalent to the specific capacity 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.

[0083] Cycle stability test:

[0084] 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 capacity of the electrode material was tested by cyclic voltammetry and constant current charge-discharge method in 1 mol / L sulfuric acid electrolyte. The specific capacity of the high-rate supercapacitor thin film electrode material prepared in examples 1-3 and comparative examples 1-5 was measured at a current density of 10 A / g, and the specific capacity retention rate (equivalent to the specific capacity 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.

[0085] Table 1: Performance test results of examples 1-3 and comparative examples 1-5

[0086]

[0087] Data analysis:

[0088] As can be seen from Table 1, the high-rate supercapacitor thin film electrode material prepared by the application has more excellent specific capacitance, rate performance and cycle stability.

[0089] This may be due to:

[0090] (1) Graphene has abundant active sites and good electrical conductivity, which can effectively improve the electron transmission rate of the electrode material. At the same time, the doping of nitrogen atoms in the preparation process of modified graphene changes the electronic structure of graphene, enhances the adsorption and storage capacity of ions in the electrolyte, and thus improves the specific capacitance, rate performance and cycle stability of the electrode material.

[0091] (2) Polyaniline has high theoretical specific capacitance and good environmental stability, and manganese dioxide has large specific surface area and abundant redox active sites. The composite nanofiber combines the advantages of both, can provide more Faraday reaction active sites in the high-rate charging and discharging process, and improve the capacitance performance of the electrode material. At the same time, the conductive performance of polyaniline helps to improve the electron transmission efficiency of manganese dioxide, further improving the rate performance of the electrode material.

[0092] (3) The inhibiting liquid can be adsorbed on the surface of active substances such as modified graphene and composite nanofiber, reduce the surface energy between particles, reduce particle agglomeration, and thus improve the consistency and stability of the performance of the finally prepared thin film electrode material; The components in the inhibiting liquid will also have a certain effect at the interface between the electrode material and the foam nickel, improve the wettability between the active substance and the foam nickel, enhance the bonding force between the active substance and the current collector, reduce the possibility of active substance falling off from the surface of the current collector during charging and discharging, improve the structural stability and electron transmission efficiency of the electrode; The addition of the sediment prepared by ball milling, centrifugation and other treatments of black phosphorus will further modify the surface properties of the sediment, so that it can better synergize with other active substances, 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 at the same time preventing the reaccumulation of other components in the mixed slurry, improving the capacitance performance and rate performance of the electrode material during high-rate charging and discharging.

[0093] (4) The heat pressing treatment can make the combination between the active substance and the current collector more closely, improve the mechanical properties and electron transmission properties of the electrode material, and thus improve the specific capacitance, rate performance and cycle stability of the high-rate supercapacitor thin film electrode material prepared by the application.

[0094] The above has been described in detail one embodiment of the present application, but the content is only the preferred embodiment of the present application, cannot be considered for limiting the scope of the present application. Any equivalent changes and improvements made in the scope of the present application, should still belong to the scope of the present application.

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: The mixed slurry is coated onto the surface of the pretreated nickel foam, then dried at 60-80℃ for 12-24h, and then hot-pressed at 120-150℃ and 5-10MPa for 10-20min 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 20-50μm; 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. Cool to room temperature and obtain modified graphene through centrifugation, washing and drying. 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. 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.

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 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.

4. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, 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.

5. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, 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.

6. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, 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.

7. The method for preparing the high-rate supercapacitor thin-film electrode material according to claim 1, 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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