Preparation method and application of manganese dioxide polyaniline MXene flexible composite

Abstract

The application discloses a preparation method and application of a manganese dioxide polyaniline MXene flexible composite material. A high-performance composite electrode material is prepared through the following steps of surface modification of polydopamine, MXene impregnation and adsorption, inert atmosphere calcination, and electrodeposition of polyaniline and manganese dioxide, and the like, with carbon cloth as a substrate. The material does not need to use a binder, effectively solves the composite problem of metal oxides, conductive polymers and metal carbides, significantly improves the stability and electrochemical performance of the electrode, and is particularly suitable for preparation of a flexible supercapacitor electrode, and has important application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite material preparation, and particularly relates to a preparation method and application of a manganese dioxide polyaniline MXene flexible composite material. BACKGROUND

[0002] With the development of science and technology, environmental protection awareness is improved, energy demand is also growing, and modern electronic products tend to be portable, flexible and wearable. Under this condition, it is urgent to develop light and flexible energy storage equipment and related materials. Supercapacitors have been attracting attention due to their high power density, good cycle stability, outstanding flexibility, fast charging and discharging speed and other advantages. The electrode material is the core part, and its performance directly determines the overall performance of the electrochemical performance of the energy storage device. The electrode materials currently studied more mainly include carbon materials, metal compounds and conductive polymers. Among them, carbon materials have high conductivity and high specific surface area, but the specific capacity is not high; conductive polymers such as polyaniline and polypyrrole have relatively high specific capacity, but also have the problem of poor stability; and metal oxides have the highest theoretical specific capacity, but the conductivity is poorer than the former two materials.

[0003] A composite material is composed of two or more materials with significantly different chemical or physical properties. In a multi-component composite material, each component provides a unique function to optimize the electrochemical performance, and when they are combined together, they can produce characteristics different from individual components, make up for the shortcomings of single-component materials, and synergistically contribute to greater advantages. In recent years, with the emergence of Mxene materials, by virtue of its unique metal conductivity and hydrophilic characteristics, mechanical and optical properties, through optimizing the structure and composite conductive materials, Mxene can significantly improve the energy density while having high conductivity, rich surface chemical properties and adjustable interlayer spacing.

[0004] For example, the patent with the application number CN202211173240.2 discloses a MXene-based composite flexible electrode material and a preparation method thereof. Ti3C2T x (MXene) dispersion liquid and CNTs dispersion liquid are alternately and repeatedly sprayed on the non-woven fabric substrate, dried, and then carbonized under a protective gas to obtain a MXene-based composite flexible electrode material.

[0005] The patent with the application number CN202411034039.5 discloses a MXene-based fiber flexible electrode material and a preparation method thereof, which comprises the following steps: spinning an aramid nanofiber spinning solution through a wet spinning process to obtain an ANF hydrogel fiber; immersing the ANF hydrogel fiber in a single-layer MXene solution to obtain a MXene@ANF hydrogel fiber; and vacuum drying the MXene@ANF hydrogel fiber to obtain a MXene@ANF fiber electrode material, that is, the MXene-based fiber flexible electrode material.

[0006] The patent with the application number CN201810544654.9 discloses a MnO2 / Ti3C2T x The preparation method of the Mxene flexible supercapacitor electrode material is realized by corroding the Al layer of Ti3AlC2 to obtain Ti3C2T x MnCl2·4H2O and Ti3C2T x The prepared MnO2 nanorods are deposited on the Ti3C2T x After the above steps, the flexible supercapacitor electrode material is obtained through washing and drying.

[0007] Although the above patents provide some methods for preparing the MXene-based flexible composite electrode material, there are still some problems, such as complex process and single active component. SUMMARY

[0008] The present application aims to overcome the defects of the prior art and provide a preparation method and application of a manganese dioxide polyaniline MXene flexible composite material.

[0009] The object of the present application can be achieved by the following technical solutions.

[0010] A preparation method of a manganese dioxide polyaniline MXene flexible composite material comprises the following steps:

[0011] Step 1: mixing Ti3AlC2 powder and HCl / LiF solution, stirring at 30-50 DEG C for 20-48 h, centrifuging, acid washing and water washing the reacted liquid several times until it is close to neutral, dissolving the precipitate in ethanol and ultrasonicating, then centrifuging, water washing, centrifuging again, taking the upper liquid to obtain a MXene dispersion liquid;

[0012] Step 2: immersing clean carbon cloth in a dopamine alkaline solution, adjusting the pH to 8-10 through tris buffer, stirring at room temperature for 2-24 h, taking out and washing with water and ethanol, and vacuum drying at 60-120 DEG C to obtain polyaniline functionalized carbon cloth;

[0013] Step 3: immerse the polydopamine functionalized carbon cloth into the MXene dispersion liquid for 1-100 min, take it out and dry at 60-120℃, and repeat the above immersion-drying process 1-10 times to adjust the loading amount of MXene on the carbon cloth, to obtain a MXene modified flexible carbon cloth;

[0014] Step 4: calcine the MXene modified flexible carbon cloth in a nitrogen or argon atmosphere furnace at a temperature rising rate of 1-10℃ / min to 400-900℃ for 1-10h to improve the conductivity of the composite material and effectively fuse and carbonize the polydopamine layer and the MXene adsorption layer, to obtain a carbonized flexible carbon cloth;

[0015] Step 5: sequentially deposit polyaniline and manganese dioxide on the carbonized flexible carbon cloth by electrochemical deposition method to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0016] More preferably, the molar ratio of HCl to LiF in the HCl / LiF solution is 9:(1-2).

[0017] More preferably, the concentration of the dopamine alkaline solution is 0.5-8g / L.

[0018] More preferably, the specific operation process of step 5 is as follows:

[0019] (1) using the carbonized flexible carbon cloth as the working electrode, platinum sheet as the counter electrode, and saturated calomel electrode as the reference electrode, deposit polyaniline in a solution containing 0.1-1M aniline and 0.1-1M sulfuric acid by an electrochemical workstation;

[0020] (2) after depositing polyaniline, the electrode is washed and placed in a solution containing 0.01-1M manganese acetate and 0.05-1M sodium acetate to deposit manganese dioxide, and after water washing, vacuum drying at 60-120℃, a manganese dioxide polyaniline MXene flexible composite material is obtained.

[0021] More preferably, the deposition voltage for depositing polyaniline by cyclic voltammetry is-0.5-1V, the scan rate is 1-100mV / s, and the deposition number of cycles is 1-30 cycles.

[0022] More preferably, the deposition voltage for depositing manganese dioxide by constant potential method is 0.7-1.3V, and the deposition time is 100-3600s.

[0023] More preferably, the manganese dioxide polyaniline MXene flexible composite material can be applied to the preparation of flexible supercapacitors.

[0024] Beneficial effects:

[0025] The application takes carbon cloth as a substrate, and sequentially prepares a high-performance composite electrode material through the steps of polydopamine surface modification, MXene impregnation and adsorption, inert atmosphere calcination, and electrodeposition of polyaniline and manganese dioxide; the material does not need to use a binder, effectively solves the composite problem of metal oxides, conductive polymers and metal carbides, significantly improves the stability and electrochemical performance of the electrode, and is particularly suitable for the preparation of flexible supercapacitor electrodes, and has important application value.

[0026] Firstly, the surface functionalization modification of polydopamine not only solves the problem of the need for a binder for the formation of conventional composite materials, but also effectively enhances the dispersion and binding firmness of MXene and other active substances on the surface of the flexible carbon cloth substrate; at the same time, the high-temperature carbonization treatment of the polydopamine layer and the MXene adsorption layer can enhance the conductivity and composite effect of the surface.

[0027] Secondly, the ternary flexible composite material of MXene, manganese dioxide and polyaniline is prepared by electrodeposition of polyaniline and manganese dioxide on the surface of the modified flexible substrate, which avoids the shortcomings of the active substance layer prepared by conventional impregnation or hydrothermal method, such as poor conductivity, poor structural stability and uneven mixing and bonding of the traditional coating method, so that the stability and electrochemical activity of the composite material are effectively improved, and thus the composite material has a wide application prospect in supercapacitor electrode materials. BRIEF DESCRIPTION OF DRAWINGS

[0028] The application will be further described below with reference to the drawings.

[0029] Figure 1 It is a preparation flow chart of the manganese dioxide polyaniline MXene flexible composite material.

[0030] Figure 2 It is a scanning electron microscope image of the manganese dioxide polyaniline MXene flexible composite material of the first embodiment of the application.

[0031] Figure 3 It is a CV curve of the manganese dioxide polyaniline MXene flexible composite material of the first embodiment of the application at different scanning speeds.

[0032] Figure 4 It is a GCD curve of the manganese dioxide polyaniline MXene flexible composite material of the first embodiment of the application at different current densities. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0034] The preparation method of the MXene solution is as follows:

[0035] The preparation of MXene first weighs 2g of LiF, and prepares 40mL of HCl (9M) and 200mL of HCl (1M). The weighed LiF is poured into a reaction kettle containing 40mL of HCl (9M) and stirred at a speed of 500r / min for 15min. 2g of Ti3AlC2 is slowly added to the reaction kettle, and stirred at 35℃ and 500r / min for 48 hours. After etching is completed, the upper liquid is poured off at a speed of 4000r / min for 5min, the obtained mixture is washed with 1M HCl and centrifuged at a speed of 4000r / min for 3min, after centrifuging 4 times, the precipitate is taken, and the precipitate is washed with deionized water at a speed of 4000r / min for 3min for multiple times, so that the pH of the supernatant is greater than 6. Then the lower precipitate is dispersed with anhydrous ethanol, and after ultrasonic treatment in an ice water bath for 60min, the ethanol is centrifuged at a speed of 10000r / min for 5min, and the upper liquid is poured off. Then, the lower precipitate is dispersed in deionized water at a speed of 4000r / min for 5min, and the supernatant is taken after centrifugation, to obtain a MXene solution.

[0036] Example one: cut a piece of 1x1.5cm carbon cloth, immerse it in 4g / L dopamine solution, adjust the pH value to about 8.5 by adding tris, and stir at room temperature for 24h, then take it out, wash it with deionized water and ethanol, and dry it in a vacuum drying box at 60℃; immerse the carbon cloth in the MXene solution for 15min, then dry it in an 80℃ oven, repeat the above steps 3 times; place the dried carbon cloth in an argon furnace and calcine it at 700℃ with a temperature rising speed of 5℃ per minute for 3h; take out the carbon cloth and place it in a mixed solution containing 0.8M aniline and 0.25M sulfuric acid, use a electrochemical workstation to perform electrodeposition on the aniline acid electrolyte solution by cyclic voltammetry, the deposition voltage range is between-0.2-0.7V, and the scan speed is 25mV / s, and the scan number is 10 circles; take out and wash it, then place it in a mixed solution containing 0.05M manganese acetate and 0.1M sodium acetate, use constant potential method, the deposition voltage is 0.9V and the deposition time is 600s, then wash it with water, dry it in a vacuum drying oven at 80℃, to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0037] Example Two: Cut a piece of carbon cloth 1 x 1.5 cm, immerse it in a 2 g / L dopamine solution, adjust the pH to about 8.5 by adding tris, and stir at room temperature for 20 h, then take it out and rinse it clean with deionized water and ethanol, and dry it in a vacuum drying oven at 80°C; immerse the carbon cloth in a MXene solution for 10 min and then dry it in an 80°C oven, repeat the above steps 2 times; place the dried carbon cloth in an argon furnace and heat it at a rate of 2°C per minute to 600°C and calcine it for 2 h; take out the carbon cloth and place it in a mixed solution containing 0.2 M aniline and 0.2 M sulfuric acid, use a cyclic voltammetry method to electrodeposit it in an aniline acidic electrolyte solution using an electrochemical workstation, the deposition voltage range is between -0.3-0.5V, and the scan rate is 15 mV / s, and the scan number is 15; take it out and rinse it, then place it in a mixed solution containing 0.3 M manganese acetate and 0.05 M sodium acetate, use a constant potential method, the deposition voltage is 0.7V and the deposition time is 500 s, then rinse it with water and dry it in a vacuum drying oven at 80°C to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0038] Example Three: Cut a piece of carbon cloth 1 x 1.5 cm, immerse it in a 1 g / L dopamine solution, adjust the pH to about 8.5 by adding tris, and stir at room temperature for 16 h, then take it out and rinse it clean with deionized water and ethanol, and dry it in a vacuum drying oven at 80°C; immerse the carbon cloth in a MXene solution for 20 min and then dry it in an 80°C oven, repeat the above steps 3 times; place the dried carbon cloth in an argon furnace and heat it at a rate of 4°C per minute to 500°C and calcine it for 3 h; take out the carbon cloth and place it in a mixed solution containing 0.4 M aniline and 0.8 M sulfuric acid, use a cyclic voltammetry method to electrodeposit it in an aniline acidic electrolyte solution using an electrochemical workstation, the deposition voltage range is between -0.1-0.9V, and the scan rate is 20 mV / s, and the scan number is 10; take it out and rinse it, then place it in a mixed solution containing 0.5 M manganese acetate and 0.7 M sodium acetate, use a constant potential method, the deposition voltage is 0.6V and the deposition time is 1000 s, then rinse it with water and dry it in a vacuum drying oven at 80°C to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0039] Example Four: A piece of carbon cloth with size of 1x1.5cm was cut, immersed in 8g / L dopamine solution, the pH value was adjusted to about 8.5 by adding tris, and stirred at room temperature for 18h, then it was taken out and washed with deionized water and ethanol, and dried in a vacuum drying oven at 80°C; the carbon cloth was immersed in MXene solution for 15min and then dried in an 80°C oven, the above steps were repeated 4 times; the dried carbon cloth was placed in an argon furnace and calcined at 650°C for 1.5h at a heating rate of 8°C per minute; after taking out the carbon cloth, it was placed in a mixed solution containing 0.7M aniline and 0.2M sulfuric acid, and electrodeposition was carried out by cyclic voltammetry in aniline acidic electrolyte solution using an electrochemical workstation, the deposition voltage was between-0.3-0.6V, the scan rate was 30mV / s, and the scan number was 15; after taking out and washing, the carbon cloth was placed in a mixed solution containing 0.1M manganese acetate and 0.3M sodium acetate, and electrodeposition was carried out by constant potential method, the deposition voltage was 1V and the deposition time was 400s, then it was washed with water and dried in a vacuum drying oven at 80°C, to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0040] Example Five: A piece of carbon cloth with size of 1x1.5cm was cut, immersed in 5g / L dopamine solution, the pH value was adjusted to about 8.5 by adding tris, and stirred at room temperature for 10h, then it was taken out and washed with deionized water and ethanol, and dried in a vacuum drying oven at 80°C; the carbon cloth was immersed in MXene solution for 50min and then dried in an 80°C oven, the above steps were repeated 4 times; the dried carbon cloth was placed in an argon furnace and calcined at 650°C for 3h at a heating rate of 5°C per minute; after taking out the carbon cloth, it was placed in a mixed solution containing 0.65M aniline and 0.15M sulfuric acid, and electrodeposition was carried out by cyclic voltammetry in aniline acidic electrolyte solution using an electrochemical workstation, the deposition voltage was between-0.2-0.9V, the scan rate was 25mV / s, and the scan number was 15; after taking out and washing, the carbon cloth was placed in a mixed solution containing 0.1M manganese acetate and 0.2M sodium acetate, and electrodeposition was carried out by constant potential method, the deposition voltage was 0.4V and the deposition time was 300s, then it was washed with water and dried in a vacuum drying oven at 80°C, to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0041] Comparative Example One: Compared with Example One, it lacks polydopamine modification, as follows:

[0042] A piece of carbon cloth with size of 1x1.5 cm was cut, and then soaked in MXene solution for 15 min and dried in an oven at 80°C. The above steps were repeated for 3 times. The dried carbon cloth was placed in an argon furnace and calcined at 700°C for 3 h with a temperature rising rate of 5°C per min. The carbon cloth was taken out and then placed in a mixed solution containing 0.8M aniline and 0.25M sulfuric acid. The electrochemical working station was used to carry out electrodeposition in aniline acid electrolyte solution by cyclic voltammetry. The deposition voltage was between -0.2-0.7V, and the scanning speed was 25mV / s, and the scanning number was 10. The carbon cloth was taken out and washed, and then placed in a mixed solution containing 0.05M manganese acetate and 0.1M sodium acetate. The constant potential method was used, the deposition voltage was 0.9V, and the deposition time was 600s. Then the carbon cloth was washed with water and dried in a vacuum drying oven at 80°C to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0043] Comparative Example Two: Compared with Example One, MXene solution was not impregnated, and the specific process was as follows:

[0044] A piece of carbon cloth with size of 1x1.5 cm was cut, and then soaked in 4g / L dopamine solution, and the pH value was adjusted to about 8.5 by adding tris, and then stirred at room temperature for 24h. Then the carbon cloth was taken out and washed with deionized water and ethanol, and then dried in a vacuum drying oven at 60°C. The dried carbon cloth was placed in an argon furnace and calcined at 700°C for 3 h with a temperature rising rate of 5°C per min. The carbon cloth was taken out and then placed in a mixed solution containing 0.8M aniline and 0.25M sulfuric acid. The electrochemical working station was used to carry out electrodeposition in aniline acid electrolyte solution by cyclic voltammetry. The deposition voltage was between -0.2-0.7V, and the scanning speed was 25mV / s, and the scanning number was 10. The carbon cloth was taken out and washed, and then placed in a mixed solution containing 0.05M manganese acetate and 0.1M sodium acetate. The constant potential method was used, the deposition voltage was 0.9V, and the deposition time was 600s. Then the carbon cloth was washed with water and dried in a vacuum drying oven at 80°C to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0045] Comparative Example Three: Compared with Example One, high-temperature calcination was not carried out, and the specific process was as follows:

[0046] A piece of carbon cloth of 1x1.5 cm is cut, immersed in a dopamine solution of 4 g / L, the pH value is adjusted to about 8.5 by adding tris, and stirred at room temperature for 24 h, then taken out and washed with deionized water and ethanol, and dried in a vacuum drying oven at 60°C; the carbon cloth is soaked in a MXene solution for 15 min and then dried in an 80°C oven, the above steps are repeated 3 times; after taking out the carbon cloth, it is placed in a mixed solution containing 0.8M aniline and 0.25M sulfuric acid, and electro-deposited in an aniline acidic electrolyte solution by an electrochemical workstation, the deposition voltage is between -0.2-0.7V, the scanning speed is 25mV / s, and the scanning number is 10 circles; after taking out and washing, the carbon cloth is placed in a mixed solution containing 0.05M manganese acetate and 0.1M sodium acetate, and deposited by constant potential method, the deposition voltage is 0.9V and the deposition time is 600s, then washed with water and dried at 80°C to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0047] Comparative Example Four: Compared with Example One, polyaniline is not deposited, and the specific process is as follows:

[0048] A piece of carbon cloth of 1x1.5 cm is cut, immersed in a dopamine solution of 4 g / L, the pH value is adjusted to about 8.5 by adding tris, and stirred at room temperature for 24 h, then taken out and washed with deionized water and ethanol, and dried in a vacuum drying oven at 60°C; the carbon cloth is soaked in a MXene solution for 15 min and then dried in an 80°C oven, the above steps are repeated 3 times; after taking out the carbon cloth, it is placed in a mixed solution containing 0.8M aniline and 0.25M sulfuric acid, and electro-deposited in an aniline acidic electrolyte solution by an electrochemical workstation, the deposition voltage is between -0.2-0.7V, the scanning speed is 25mV / s, and the scanning number is 10 circles; after taking out and washing, the carbon cloth is placed in a mixed solution containing 0.05M manganese acetate and 0.1M sodium acetate, and deposited by constant potential method, the deposition voltage is 0.9V and the deposition time is 600s, then washed with water and dried at 80°C to obtain a manganese dioxide polyaniline MXene flexible composite material.

[0049] Test experiment:

[0050] (1) The microstructure of the manganese dioxide polyaniline MXene flexible composite material obtained in Example One is observed by scanning electron microscopy, and the results are shown in Figure 2 ;

[0051] (2) A saturated calomel electrode is used as a reference electrode, a platinum sheet is used as an auxiliary electrode, and a test is performed in a 1M Na2SO4 solution electrolyte, and the manganese dioxide polyaniline MXene flexible composite material obtained in Example One is tested by an electrochemical workstation, the voltage range is 0-0.6V, and the cyclic voltammetry (CV) curves at different scanning speeds are recorded, and the results are shown in Figure 3 ;

[0052] (3) Using saturated calomel electrode as reference electrode and platinum plate as auxiliary electrode, the manganese dioxide polyaniline MXene flexible composite material obtained in the examples and the comparative examples was subjected to constant current charge-discharge cycle performance test in 1M Na2SO4 solution electrolyte by using an electrochemical workstation, the voltage range was set to 0-0.8V, and the discharge time and other data under different current densities were recorded, the electrode specific capacitance at a current density of 1A / g was calculated according to the formula C=(I·Δt) / (m·ΔV) (C (F / g) represents electrode specific capacitance, I (A) represents discharge current size, Δt (s) represents discharge time, m (g) represents active material, and ΔV (V) represents voltage window range), and the specific data are shown in the following table; in addition, the galvanostatic charge-discharge (GCD) curve of Example 1 was recorded, and the results are shown in Figure 4 .

[0053]

[0054] Table 1

[0055] Conclusion: The four key steps of polydopamine modification, MXene introduction, high-temperature calcination and polyaniline deposition synergistically ensure the excellent electrochemical performance of the composite material. As the best embodiment, Figures 2-4 known that the electrodeposition method makes the active material loaded on the surface of the electrode material very uniform, greatly increases the contact area of the electrode material and the electrolyte solution, the MXene layer can enhance the binding ability of the polydopamine and MnO2 material and the carbon cloth substrate, the calcined MXene layer can make the active material more uniform, and plays a linking role during the compounding, greatly improving the stability of the material; the CV curve at different scan rates and the galvanostatic charge-discharge curve at different current densities have good symmetry, which shows that the composite material has good redox property.

[0056] And, by comparing the examples and the comparative examples (as shown in Table 1):

[0057] Firstly, the absence of polydopamine (PDA) surface modification (Comparative Example 1) will significantly reduce the electrochemical performance of the material, which is mainly due to the fact that PDA modification can effectively enhance the binding force between the active material and the carbon cloth fiber. The lack of this step will lead to uneven distribution and poor combination of the active material.

[0058] Secondly, the introduction of MXene active material is crucial (Comparative Example 2). MXene as a highly conductive base material can construct a three-dimensional conductive network, which just makes up for the inherent defects of polyaniline conductivity depending on doping. Experimental data confirms that the specific capacitance of the material lacking MXene will decrease significantly.

[0059] Furthermore, the high-temperature calcination step (Comparative Example Three) cannot be ignored for the optimization of material performance. The calcination process not only improves the overall conductivity of the composite material, but also makes the distribution of the subsequent electrodeposited polyaniline and manganese dioxide more uniform, effectively reducing the stacking phenomenon between molecules.

[0060] Finally, the introduction of polyaniline (Comparative Example Four) plays a unique role. It can form a cross-linked network between manganese dioxide particles, on the one hand preventing the agglomeration of manganese dioxide particles, and on the other hand increasing the specific surface area of the material, thereby providing more electrochemically active sites. The lack of this component will also lead to a significant decrease in specific capacitance.

[0061] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0062] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as it does not deviate from the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A method for preparing a manganese dioxide polyaniline MXene flexible composite material, characterized by comprising the following steps: Comprising the following steps: ​ Step 1: mixing Ti3AlC2 powder with HCl / LiF solution, stirring at 30-50℃ for 20-48h, centrifuging, washing, ethanol ultrasonic dispersion, taking the supernatant, and preparing MXene dispersion; Step 2: immersing clean carbon cloth into dopamine alkaline solution, adjusting pH to 8-10, stirring at room temperature for 2-24h, washing with water and ethanol, and vacuum drying at 60-120℃ to obtain polydopamine functionalized carbon cloth; Step 3: immersing polydopamine functionalized carbon cloth into MXene dispersion for 1-100min, taking out and drying at 60-120℃, and repeating the above immersion-drying process 1-10 times to obtain MXene modified flexible carbon cloth; Step 4: calcining MXene modified flexible carbon cloth under inert atmosphere at a temperature rising rate of 1-10℃ / min to 400-900℃ for 1-10h to obtain carbonized flexible carbon cloth; Step 5: sequentially depositing polyaniline and manganese dioxide on the carbonized flexible carbon cloth by electrochemical deposition to obtain manganese dioxide polyaniline MXene flexible composite.

2. The method of claim 1, wherein the method of preparing a manganese dioxide polyaniline MXene flexible composite is characterized by: In the HCl / LiF solution, the molar ratio of HCl to LiF is 9:(1-2).

3. The method of claim 1, wherein the method comprises: The concentration of the dopamine alkaline solution is 0.5-8g / L.

4. The method of claim 1, wherein the method of preparing a manganese dioxide polyaniline MXene flexible composite is characterized by: The specific operation process of step 5 is: (1) using carbonized flexible carbon cloth as working electrode, depositing polyaniline in a solution containing 0.1-1M aniline and 0.1-1M sulfuric acid; (2) washing the electrode after depositing polyaniline, depositing manganese dioxide in a solution containing 0.01-1M manganese acetate and 0.05-1M sodium acetate, washing with water, and vacuum drying at 60-120℃ to obtain manganese dioxide polyaniline MXene flexible composite.

5. The method of claim 4, wherein the method comprises: The polyaniline is deposited by cyclic voltammetry, the deposition voltage is-0.5-1V, the scan rate is 1-100mV / s, and the deposition number is 1-30.

6. The method of claim 4, wherein the method is characterized by: The manganese dioxide is deposited by constant potential method, the deposition voltage is 0.7-1.3V, and the deposition time is 100-3600s.

7. A manganese dioxide polyaniline MXene flexible composite material characterized by: Prepared according to the preparation method of any one of claims 1-6.

8. Use of the manganese dioxide polyaniline MXene flexible composite of claim 7 in the preparation of flexible supercapacitors.

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