Asymmetric polypyrrole nanotube array film electrode material and preparation and application thereof

Abstract

The invention belongs to the technical field of supercapacitors, and relates to an asymmetric polypyrrole nanotube array film electrode material and preparation and application thereof.The preparation method comprises the steps that pyrrole and an oxidizing agent are prepared into a mixed solution, a porous film is placed on the liquid level of the mixed solution, a low-temperature reaction is conducted, a film material is taken out, the porous film is removed, and the asymmetric polypyrrole nanotube array film electrode material is obtained. The asymmetric polypyrrole nanotube array film is obtained. Compared with the prior art, the asymmetric thin film takes the polycarbonate porous film as a template, and the asymmetric thin film structure can be obtained through a solution method. And compared with an existing hard template method, the preparation method has the advantages that the cost is reduced, and the process is simplified.

Description

Technical Field

[0001] The present invention belongs to the technical field of supercapacitors, and relates to an asymmetric polypyrrole nanotube array thin film electrode material and its preparation and application. Background Art

[0002] In modern industrial production and life, electrical energy is the main way of energy utilization. With the increasing energy demand of hybrid electric vehicles and mobile electronic devices, efficient and safe energy storage devices have become the focus of research by scientific researchers. Supercapacitors have attracted extensive research interest due to their advantages such as high power density, fast charge and discharge, safety, environmental friendliness, and long service life. With the increasing energy demand of hybrid electric vehicles and mobile electronic devices, there is an urgent need to explore new materials with high specific capacitance, high conductivity, and electrochemical stability to meet the energy storage requirements. Electrode materials are an important factor determining the performance of supercapacitors. Usually, electrode materials are classified into electric double layer capacitor electrode materials and pseudocapacitor electrode materials according to different energy storage mechanisms. For electric double layer capacitors and pseudocapacitors, during the charge and discharge process, the storage and release of energy occur inside or on the surface of the electrode material. Therefore, electrode materials with a large specific surface area and efficient electron transport pathways can exhibit high specific capacitance. Polypyrrole (PPy) is an important conductive polymer with good flexibility, conductivity, and energy storage performance, and is therefore considered to be a supercapacitor functional material with great utilization value.

[0003] Polypyrrole has many remarkable characteristics such as high conductivity, simple synthesis, low cost, good biocompatibility, and environmental friendliness, which are all due to the extended π-bond system in its special structure. Due to these inherent properties, polypyrrole has been widely studied in the fields of biosensors, mechanical actuators, drug delivery systems, and supercapacitors. Polypyrrole captures or releases electrons through an oxidation-reduction process to maintain the charge neutrality of the polymer chain. This reversible co-ion doping / dedoping characteristic makes it have excellent performance as a supercapacitor electrode material. Summary of the Invention

[0004] The purpose of the present invention is to provide an asymmetric polypyrrole nanotube array thin film electrode material that does not require the aid of a hard template, has a simple, efficient, and controllable method, is easy to implement, and its preparation and application in supercapacitors.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The inventors have learned that organic materials, especially conductive polymers, are favored by researchers in the sensing field due to their advantages such as flexibility, adjustable conductivity, and good biocompatibility. Asymmetric nanotube arrays can expose more active sites for energy storage.

[0007] Therefore, the development of nanostructured polymer materials is expected to achieve supercapacitors with high specific capacitance. As a typical conductive polymer, polypyrrole is simple to prepare, has a controllable structure, and good conductivity, and has a wide range of applications in the field of supercapacitors. The asymmetric thin film structure includes a continuous porous membrane and a hollow tube array on the membrane, providing an ultra-high specific surface area, which can greatly improve the energy storage of supercapacitors.

[0008] The present invention provides a simple, efficient and controllable method for preparing an asymmetric polypyrrole nanotube array thin film. By placing a polycarbonate porous membrane on the surface of an oxidant solution and a pyrrole dispersion, pyrrole can be polymerized under the bottom surface and in the pores of the porous membrane by capillary force to form an asymmetric polypyrrole nanotube array. After removing the template, an asymmetric polypyrrole nanotube array thin film can be obtained. This asymmetric thin film can be used to construct a supercapacitor. The specific scheme is as follows:

[0009] The first aspect of the present invention provides a method for preparing an asymmetric polypyrrole nanotube array thin film electrode material, including: preparing a mixed solution by mixing pyrrole and an oxidant, placing the porous membrane on the liquid surface of the mixed solution, reacting at a low temperature, taking out the membrane material, and removing the porous membrane to obtain an asymmetric polypyrrole nanotube array thin film.

[0010] Further, the mixed solution is obtained by dropwise adding a pyrrole dispersion to an oxidant solution and stirring;

[0011] Among them, the preparation process of the pyrrole dispersion is: mixing pyrrole monomer with an acid solution to obtain a pyrrole monomer solution.

[0012] Further, the mixing volume ratio of the pyrrole monomer to the acid solution is (50 - 400) μL: 15 mL. Among them, in the acid solution, the proton acid used is hydrochloric acid or sulfuric acid, and the hydrogen ion concentration is 0.1 - 1 M. The preferred volume ratio is 200 μL: 15 mL. When the pyrrole dispersion is certain, the inner diameter of the polypyrrole nanotube will decrease with the increase of the pyrrole concentration.

[0013] Further, the oxidant solution is an acidic iron salt solution, and the acidic iron salt solution is obtained by mixing an iron salt and an acid at a feeding ratio of (0.1 - 1) g: 15 mL. Among them, the proton acid used is hydrochloric acid or sulfuric acid, the hydrogen ion concentration in the acidic iron salt solution is 0.1 - 1 M, and the concentration of the iron salt is 0.05 - 0.5 M. Preferably, the iron salt used is ferric chloride or ferric sulfate. The present invention uses a polycarbonate porous membrane as a template for the formation of a polypyrrole hollow nanotube array. Ferric chloride or ferric sulfate with a concentration of 0.1 - 0.4 M can be selected to polymerize pyrrole. The conductivity of the polypyrrole nanotube array thin films prepared with different concentrations of iron salt solutions is different. As the iron salt concentration decreases, the polymerization rate slows down, the polypyrrole chain lengthens, and the conductivity increases.

[0014] Further, the mixing volume ratio of the pyrrole dispersion liquid to the oxidant solution is (200 - 2000) μL : (3 - 5) mL.

[0015] The relative dosage of the pyrrole dispersion liquid is 200 - 2000 μL. The pyrrole monomer dispersion liquid is added dropwise to the iron chloride solution. The polycarbonate porous membrane is placed on the liquid surface. Under the action of capillary force, the solution will enter the pores of the porous membrane. Under the action of π-π bonds and hydrogen bonds, the pyrrole monomers will spontaneously connect to the surface and inside the pores of the polycarbonate, and are oxidized by iron chloride to form a polypyrrole layer on the surface and inside the pores of the polycarbonate porous membrane. The thickness of the polypyrrole layer will increase with the increase in the dosage of the pyrrole dispersion liquid.

[0016] Further, the porous membrane is a polycarbonate porous membrane, which is removed by dissolving in dichloromethane or N,N-dimethylformamide. The dichloromethane or N,N-dimethylformamide is used as a solvent, and the immersion time of the porous membrane in the solvent is not less than 5 min.

[0017] Preferably, the porous membrane always floats on the liquid surface rather than being immersed in the liquid during the reaction.

[0018] Further, the pore diameter of the porous membrane is 0.05 - 10 μm, preferably 0.2 - 2 μm. Polycarbonate porous membranes with different pore diameters can be selected, and the pore diameters of the prepared polypyrrole arrays will change accordingly.

[0019] Further, in the low-temperature reaction, the reaction temperature is 0 - 8 °C, and the reaction time is 8 - 12 h.

[0020] Further, after the membrane material is taken out from the liquid surface, it is washed with ethanol at least 3 times.

[0021] The second aspect of the present invention provides an asymmetric polypyrrole nanotube array thin film electrode material, which is prepared by the method described above.

[0022] The third aspect of the present invention provides an application of the asymmetric polypyrrole nanotube array thin film electrode material, including using the asymmetric polypyrrole nanotube array thin film electrode material to construct a supercapacitor.

[0023] Compared with the prior art, the present invention has the following characteristics:

[0024] 1) The asymmetric thin film of the present invention uses a polycarbonate porous membrane as a template, and an asymmetric thin film structure can be obtained by a solution method. The preparation is simple, efficient, and easy to implement. Compared with the existing hard template method, it not only reduces the cost but also simplifies the process;

[0025] 2) The preparation method of the present invention mainly prepares an asymmetric polypyrrole nanotube array film through a simple solution synthesis step, and an asymmetric film can be obtained without additional surface treatment, which simplifies the process;

[0026] 3) The asymmetric film prepared by the present invention can be used to construct a supercapacitor, with low cost and high efficiency. Description of the Drawings

[0027] Figure 1 is the preparation flow chart of the asymmetric polypyrrole film in the present invention;

[0028] Figure 2 is the scanning electron microscope image of the asymmetric polypyrrole film prepared from a 0.2 μm polycarbonate porous membrane in Example 1;

[0029] Figure 3 is the scanning electron microscope image of the asymmetric polypyrrole film prepared from a 0.1 μm polycarbonate porous membrane in Example 2;

[0030] Figure 4 is the scanning electron microscope image of the asymmetric polypyrrole film prepared from a 2 μm polycarbonate porous membrane in Example 3;

[0031] Figure 5 is the scanning electron microscope image of the asymmetric polypyrrole film prepared from a 0.6 μm polycarbonate porous membrane in Example 4;

[0032] Figure 6 is the cyclic voltammetry test result graph of the supercapacitor prepared from the 0.6 μm asymmetric polypyrrole nanotube array film in Example 4.

[0033] Figure 7 is the electrochemical impedance test result graph of the supercapacitor prepared from the 0.6 μm asymmetric polypyrrole nanotube array film in Example 4. Detailed Embodiments

[0034] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0035] A preparation method of an asymmetric polypyrrole nanotube array film, the method comprising the following steps:

[0036] Immerse the flexible and degradable porous filter membrane in the oxidant solution; the degradable porous filter membrane includes a polycarbonate filter membrane; the oxidant solution includes an acidic ferric chloride solution and a ferric sulfate solution; the degradable porous filter membrane is a polycarbonate filter membrane; the protonic acid includes hydrochloric acid and sulfuric acid; the oxidant solution is an acidic iron salt solution. The pore size of the polycarbonate filter membrane is 0.05 - 10 μm, preferably 0.2 - 2 μm; polycarbonate porous membranes with different pore sizes can be selected, and the pore size of the prepared polypyrrole array will change accordingly. In the acidic iron salt solution, the dosage ratio of the iron salt to the acid is (0.1 - 1) g:15 mL, the concentration of the acid is 0.1 - 1 M, and the concentration of the iron salt is 0.05 - 0.5 M; when using the polycarbonate porous membrane as the template for forming the polypyrrole hollow nanotube array, ferric chloride with a concentration of 0.05 - 0.5 M can be used to polymerize pyrrole, and the conductivity of the polypyrrole nanotube array film prepared with different concentrations of ferric chloride is different. As the concentration of ferric chloride decreases, the polymerization rate slows down, the polypyrrole chain lengthens, and the conductivity increases. In the acidic iron salt solution, the iron salt is ferric chloride and the acid is hydrochloric acid.

[0037] Drop the pyrrole dispersion into the oxidant solution soaked with the porous filter membrane, and carry out freezing and static reaction; the preparation process of the pyrrole dispersion is: mix the pyrrole monomer with the aqueous solution of the protonic acid to obtain the pyrrole monomer solution; in the pyrrole dispersion, the dosage ratio of the pyrrole monomer to the hydrochloric acid aqueous solution is (50 - 400) μL:15 mL, and the concentration of hydrochloric acid is 0.1 - 1 M; the dosage of the pyrrole monomer is 50 - 400 μL. When the pyrrole dispersion is certain, the thickness of the polypyrrole layer will increase with the increase of the pyrrole concentration. The volume ratio of the pyrrole dispersion to the acidic iron salt solution is (200 - 2000) μL:(3 - 5) mL. The dosage of the pyrrole dispersion is 200 - 2000 μL. Drop the pyrrole monomer dispersion into the ferric chloride solution soaked with the polycarbonate porous membrane. Under the action of π - π bonds and hydrogen bonds, the pyrrole monomers will spontaneously connect to the surface and pores of the polycarbonate, and be oxidized by ferric chloride to form a polypyrrole layer on the surface and in the pores of the polycarbonate porous membrane. The thickness of the polypyrrole layer will increase with the increase of the dosage of the pyrrole dispersion. The freezing ambient temperature is lower than 8 °C (preferably 0 - 8 °C), and the static time is not less than 8 h (preferably 8 - 12 h).

[0038] Take out the reacted porous filter membrane, and wash and dry it; use clear water for washing, and the number of cleaning and washing times is not less than 3 times.

[0039] Put the washed porous filter membrane into the solvent to remove the porous filter membrane. After cleaning and drying, an asymmetric polypyrrole nanotube array film is obtained, and this film is applied to construct a supercapacitor. The solvent includes dichloromethane, and ethanol is used for washing. The time for putting it into the solvent is not less than 5 min, and the number of cleaning and washing times is not less than 3 times.

[0040] Typical operation methods, such as Figure 1, including the following steps:

[0041] Step 1: Dissolve a certain amount of oxidant in 15 mL of acid solution to obtain an oxidant solution; the oxidant is ferric chloride or ferric sulfate with a concentration of 0.1 - 0.4 M, and the acid is hydrochloric acid or sulfuric acid. The concentration of hydrochloric acid is 0.1 - 1 M, and the concentration of sulfuric acid is 0.05 - 0.5 M.

[0042] Step 2: Take 3 - 5 mL of acidic iron salt solution, add pyrrole dispersion dropwise and shake well; the concentration of pyrrole dispersion is 0.1 - 0.4 M. The dosage of pyrrole dispersion is 200 - 2000 μL.

[0043] Step 3: Place the polycarbonate porous membrane on the surface of the solution; the pore size of the polycarbonate porous membrane is 0.05 - 10 μm, and let it stand in the refrigerator for 8 hours.

[0044] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in the oven for drying;

[0045] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain an asymmetric polypyrrole thin film, and apply it to construct a supercapacitor.

[0046] This embodiment is implemented on the premise of the technical solution of the present invention, and gives detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0047] Example 1

[0048] An asymmetric polypyrrole nanotube array thin film, and its preparation method includes the following:

[0049] Step 1: Dissolve 1 g of ferric chloride in 100 mL of 0.1 M hydrochloric acid solution to obtain a ferric chloride solution;

[0050] Step 2: Take 5 mL of ferric chloride solution; take 200 μL of pyrrole monomer and disperse it evenly with 15 mL of 0.1 M hydrochloric acid solution to obtain a pyrrole dispersion, and take 200 μL of pyrrole dispersion and add it dropwise to the ferric chloride solution and shake well;

[0051] Step 3: Place a polycarbonate porous membrane with a pore size of 0.2 μm on the liquid surface of the above - mentioned mixed solution, and let it stand in a 5 °C refrigerator for 8 hours;

[0052] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in the oven for drying;

[0053] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain the Figure 2 asymmetric polypyrrole film attached.

[0054] Example 2

[0055] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0056] Step 1: Dissolve 0.1 g of ferric chloride in 15 mL of 0.1 M hydrochloric acid solution to prepare a ferric chloride solution;

[0057] Step 2: Take 5 mL of the ferric chloride solution, take 200 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.1 M hydrochloric acid solution to obtain a pyrrole dispersion. Take 1000 μL of the pyrrole dispersion and drop it into the ferric chloride solution, and shake well;

[0058] Step 3: Place a polycarbonate porous membrane with a pore size of 0.1 μm on the liquid surface and let it stand in a 5 °C refrigerator for 8 hours;

[0059] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in an oven to dry;

[0060] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain the Figure 3 asymmetric polypyrrole film attached.

[0061] Example 3

[0062] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0063] Step 1: Dissolve 0.5 g of ferric sulfate in 15 mL of 0.05 M sulfuric acid solution to prepare a ferric sulfate solution;

[0064] Step 2: Take 5 mL of the ferric sulfate solution, take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.05 M sulfuric acid solution to obtain a pyrrole dispersion. Take 1000 μL of the pyrrole dispersion and drop it into the ferric sulfate solution, and shake well;

[0065] Step 3: Place a polycarbonate porous membrane with a pore size of 2 μm on the liquid surface and let it stand in a 5 °C refrigerator for 8 hours;

[0066] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in an oven to dry;

[0067] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain the Figure 4 asymmetric polypyrrole film attached.

[0068] Example 4

[0069] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0070] Step 1: Dissolve 0.1 g of ferric chloride in 15 mL of 0.1 M hydrochloric acid solution to prepare a ferric chloride solution;

[0071] Step 2: Take 5 mL of the ferric chloride solution, take 200 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.1 M hydrochloric acid solution to obtain a pyrrole dispersion. Take 600 μL of the pyrrole dispersion and drop it into the ferric chloride solution, and shake well;

[0072] Step 3: Place a polycarbonate porous membrane with a pore size of 0.6 μm on the liquid surface and let it stand in a 5 °C refrigerator for 8 hours;

[0073] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in an oven to dry;

[0074] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain the Figure 5 asymmetric polypyrrole film with a pore size of 0.6 μm as shown.

[0075] Cut the asymmetric polypyrrole film prepared in the above steps of this example into a size of 1×2 mm 2 , stick it on the conductive tape as the working electrode, use a platinum sheet as the counter electrode, a calomel electrode as the reference electrode, and a 0.5 M sulfuric acid solution as the electrolyte to form a three-electrode system. Use a Chenhua electrochemical workstation to perform cyclic tests and electrochemical impedance tests on the three electrodes at different scanning rates. The results are shown in the attached Figure 6 and attached Figure 7 respectively. As shown in Figure 6 , the performance of the supercapacitor is detected using cyclic voltammetry. The specific capacitances at 2, 5, 10, 20, 50, 100, and 200 mV / s are 207.5, 163.6, 173.9, 162.9, 147.0, 131.8, and 110 F / g respectively. The results show that when the scanning rate increases from 2 mV / s to 200 mV / s, the electrode can maintain 53% of the capacitance, showing good stability. Figure 7 shows the Nyquist curve in the frequency range of 0.01 to 100000 Hz, and its internal resistance and charge transfer resistance are 0.9 Ω and 3.5 Ω respectively.

[0076] Example 5: Different dosages of iron salts in the oxidant solution

[0077] An asymmetric polypyrrole nanotube array film and a preparation method thereof are as follows:

[0078] Step 1: Dissolve 0.1 g, 0.3 g, 0.8 g, and 1 g of ferric sulfate in 15 mL of 0.05 M sulfuric acid solution respectively to obtain ferric sulfate solutions;

[0079] Step 2: Take 5 mL of the ferric sulfate solution, take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.05 M sulfuric acid solution to obtain a pyrrole dispersion. Take 1000 μL of the pyrrole dispersion and drop it into the ferric sulfate solution, and shake well;

[0080] Step 3: Place a polycarbonate porous membrane with a pore size of 2 μm on the liquid surface and place it in a refrigerator at 2 °C for 8 hours;

[0081] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in an oven for drying;

[0082] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain an asymmetric polypyrrole film.

[0083] Example 6: Different acid concentrations in the oxidant solution and the pyrrole dispersion

[0084] An asymmetric polypyrrole nanotube array film and a preparation method thereof are as follows:

[0085] Step 1: Dissolve 0.5 g of ferric sulfate in 15 mL of 0.1 M, 0.15 M, 0.2 M, 0.4 M, and 0.5 M sulfuric acid solutions respectively to obtain ferric sulfate solutions;

[0086] Step 2: Take 5 mL of the ferric sulfate solution, take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.1 M, 0.15 M, 0.2 M, 0.4 M, and 0.5 M sulfuric acid solutions respectively to obtain pyrrole dispersions. Take 1000 μL of the pyrrole dispersion and drop it into the ferric sulfate solution, and shake well;

[0087] Step 3: Place a polycarbonate porous membrane with a pore size of 2 μm on the liquid surface and place it in a refrigerator at 2 °C for 8 hours;

[0088] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in an oven for drying;

[0089] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain the asymmetric polypyrrole film.

[0090] Example 7: Volume ratio of different oxidant solutions to pyrrole dispersions

[0091] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0092] Step 1: Dissolve 0.5 g of ferric sulfate in 15 mL of 0.5 M sulfuric acid solution respectively to prepare ferric sulfate solutions.

[0093] Step 2: Take 3 mL, 4 mL, and 5 mL of ferric sulfate solutions respectively. Take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.5 M sulfuric acid solution to obtain pyrrole dispersions. Take 1000 μL of pyrrole dispersions and add them dropwise to the corresponding ferric sulfate solutions respectively, and shake well.

[0094] Step 3: Place a polycarbonate porous membrane with a pore size of 2 μm on the liquid surface and let it stand in a refrigerator at 2 °C for 8 hours.

[0095] Step 4: Take out the reacted polycarbonate porous membrane, wash it three times with deionized water and place it in an oven to dry.

[0096] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain the asymmetric polypyrrole film.

[0097] Example 8: Volume ratio of different oxidant solutions to pyrrole dispersions

[0098] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0099] Step 1: Dissolve 0.5 g of ferric sulfate in 15 mL of 0.5 M sulfuric acid solution respectively to prepare ferric sulfate solutions.

[0100] Step 2: Take 3 mL of ferric sulfate solution. Take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.5 M sulfuric acid solution to obtain pyrrole dispersions. Take 200 μL, 400 μL, 600 μL, 800 μL, 1000 μL, 1200 μL, 1400 μL, 1600 μL, 1800 μL, and 2000 μL of pyrrole dispersions respectively and add them dropwise to the corresponding ferric sulfate solutions, and shake well.

[0101] Step 3: Place a polycarbonate porous membrane with a pore size of 2 μm on the liquid surface and let it stand in a refrigerator at 2 °C for 8 hours.

[0102] Step 4: Take out the polycarbonate porous membrane after the reaction, wash it three times with deionized water and place it in an oven for drying;

[0103] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain an asymmetric polypyrrole film.

[0104] Example 9: Different pore sizes of porous membranes

[0105] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0106] Step 1: Dissolve 0.5 g of ferric sulfate in 15 mL of 0.5 M sulfuric acid solution respectively to prepare ferric sulfate solution;

[0107] Step 2: Take 3 mL of ferric sulfate solution, take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.5 M sulfuric acid solution to obtain a pyrrole dispersion. Take 200 μL of the pyrrole dispersion and drop it into the corresponding ferric sulfate solution respectively, and shake well;

[0108] Step 3: Place polycarbonate porous membranes with pore sizes of 0.05 μm, 0.1 μm, 0.2 μm, 0.4 μm, 0.8 μm, 1.2 μm, 1.5 μm, 2 μm, 4 μm, 6 μm, 8 μm, and 10 μm on the liquid surface respectively, and place them in a refrigerator at 2 °C for 8 hours;

[0109] Step 4: Take out the polycarbonate porous membrane after the reaction, wash it three times with deionized water and place it in an oven for drying;

[0110] Step 5: Immerse the dried porous membrane in dichloromethane for 5 minutes to remove the polycarbonate porous membrane template, then wash it three times with ethanol and dry it to obtain an asymmetric polypyrrole film.

[0111] Example 10: Different reaction temperatures

[0112] An asymmetric polypyrrole nanotube array film and its preparation method are as follows:

[0113] Step 1: Dissolve 0.5 g of ferric sulfate in 15 mL of 0.5 M sulfuric acid solution respectively to prepare ferric sulfate solution;

[0114] Step 2: Take 3 mL of ferric sulfate solution, take 300 μL of pyrrole monomer and disperse it evenly in 15 mL of 0.5 M sulfuric acid solution to obtain a pyrrole dispersion. Take 200 μL of the pyrrole dispersion and drop it into the corresponding ferric sulfate solution respectively, and shake well;

[0115] Step 3: Place the polycarbonate porous membranes with a pore size of 2 μm on the liquid surface and place them in a refrigerator at 2 °C, 4 °C, and 8 °C for 8 hours of static settlement respectively;

[0116] Step 4: Take out the reacted polycarbonate porous membranes, wash them three times with deionized water and place them in an oven for drying;

[0117] Step 5: Immerse the dried porous membranes in dichloromethane for 5 minutes to remove the polycarbonate porous membrane templates, then wash them three times in ethanol and dry them to obtain asymmetric polypyrrole thin films.

[0118] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A preparation method of an asymmetric polypyrrole nanotube array thin film electrode material, characterized in that Comprising: Prepare a mixed solution by mixing pyrrole with an oxidant. Place the porous membrane on the liquid surface of the mixed solution, react at a low temperature, take out the membrane material, and remove the porous membrane to obtain an asymmetric polypyrrole nanotube array thin film.

2. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 1, characterized in that The mixed solution is obtained by dropwise adding a pyrrole dispersion to an oxidant solution and stirring; Among them, the preparation process of the pyrrole dispersion is: mix pyrrole monomers with an acid solution to obtain a pyrrole monomer solution.

3. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 2, characterized in that, The mixing volume ratio of the pyrrole monomer to the acid solution is (50 - 400) μL: 15 mL. In the acid solution, the proton acid used is hydrochloric acid or sulfuric acid, and the hydrogen ion concentration is 0.1 - 1 M.

4. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 2, characterized in that, The oxidant solution is an acidic iron salt solution, which is obtained by mixing an iron salt and an acid at a feeding ratio of (0.1 - 1) g: 15 mL. The proton acid used is hydrochloric acid or sulfuric acid. The hydrogen ion concentration in the acidic iron salt solution is 0.1 - 1 M, and the concentration of the iron salt is 0.05 - 0.5 M.

5. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 2, characterized in that The mixing volume ratio of the pyrrole dispersion to the oxidant solution is (200 - 2000) μL: (3 - 5) mL.

6. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 1, characterized in that The porous membrane is a polycarbonate porous membrane, which is removed by dissolving with dichloromethane or N,N-dimethylformamide.

7. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 1, characterized in that, The pore size of the porous membrane is 0.05 - 10 μm.

8. The preparation method of the asymmetric polypyrrole nanotube array thin film electrode material according to claim 1, characterized in that In the low-temperature reaction, the reaction temperature is 0 - 8 °C, and the reaction time is 8 - 12 h.

9. An asymmetric polypyrrole nanotube array thin film electrode material, characterized in that, It is prepared by the method described in any one of claims 1 to 8.

10. Application of the asymmetric polypyrrole nanotube array thin film electrode material as described in claim 9, characterized in that, The described asymmetric polypyrrole nanotube array thin film electrode material is used to construct a supercapacitor.

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