Electrode with stable electrochemical performance based on aniline and ortho-methoxy-4-aniline sulfonate copolymer and preparation method thereof

Abstract

The invention relates to a preparation method of a novel composite material for a supercapacitor electrode, and belongs to the field of high polymer chemistry and supercapacitors. In the work, the electrode material (MX / ASAN) is prepared by carrying out in-situ polymerization on aniline and ortho-methoxyaniline copolymer (ASAN) and MXene, and the long-term cycling stability of the composite electrode is further improved by utilizing the interaction between two-dimensional MXene material nanosheet layers on the premise of giving full play to the ultrahigh specific capacitance of a conductive polymer. The prepared MX / ASAN composite electrode has high specific capacitance of 549F / g and excellent stability, and still has a capacitance retention rate of 87% even after 10000 times of cycle charging and discharging.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of polymer chemistry and supercapacitors, and relates to a preparation method of a three-component composite electrode material for aniline, aniline derivatives and MXene. BACKGROUND

[0002] A supercapacitor is mainly composed of three parts: an electrode material, an electrolyte and a current collector. However, the electrode as the core component of the supercapacitor plays a key role in the performance of the supercapacitor. The active substances commonly used in supercapacitors mainly include conductive polymers (polyaniline, polypyrrole, polythiophene), metal oxides (MnO2, CeO2, NiO...) and two-dimensional materials. At present, two-dimensional materials are a kind of electrode material with high expectations, mainly because they have a very high specific surface area, providing more reaction sites for double-layer or fast redox reactions. MXene is a two-dimensional material composed of transition metal carbides and nitrides, and has good solubility in various common solvents, and is widely studied for battery energy storage systems, electromagnetic shielding and many other applications. Therefore, the conductive polymer is compounded with MXene, the advantages of the two are combined, and a new type of electrode material of the conductive polymer-based composite is prepared, which is also one of the most potential directions of the current innovative research of the supercapacitor. SUMMARY

[0003] The application aims to provide a composite electrode for a supercapacitor and a preparation method thereof, the composite electrode has a large capacitance value and good electrochemical performance, is applied to a supercapacitor, has a high specific capacitance of 549 F / g, and has a high capacitance retention rate of up to 87% after 10000 cycles, thereby embodying excellent long-term cycle stability, and the preparation method is simple in process and low in cost. A novel electrode material for a supercapacitor is characterized by in-situ polymerization of aniline and ortho-methoxy aniline on the surface of MXene to generate a random copolymer ASAN, which can not only prevent self-stacking of the MXene material, but also can serve as an intermediate layer, so that the electrochemical performance of ASAN / MXene is improved. The composition is as follows: ASAN: 95% MXene: 5%

[0004] The application further provides a preparation method of a composite electrode for a supercapacitor, comprising the following steps.

[0005] Step one: the Ti3AlC2 powder is subjected to acid etching by an indirect acid etching method to prepare a multi-layer MXene (Ti3AlC x ) powder.

[0006] Step two: copolymerization of monomers in the stable MXene dispersion solution. The precipitate ASAN / MXene generated in the reaction is filtered, washed, and dried.

[0007] Step three: the obtained ASAN / MXene composite material is uniformly scraped on the surface of the carbon paper and dried in a vacuum oven at 60°C, and finally a composite supercapacitor electrode is obtained. Preferably, the ASAN / MXene composite material is prepared by solution polymerization, and the product obtained above is coated on the current collector to prepare a composite supercapacitor electrode by in-situ polymerization. Preferably, the preparation method of the supercapacitor electrode of the conductive polymer (ASAN) and MXene composite is characterized in that the proportion of ASAN to MXene in the ASAN / MXene composite material is 1:0.05. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 The preparation process of the MXene / ASAN composite material is shown; Figure 2 The CV curves of the MXene / ASAN composite electrodes with different proportions are shown; Figure 3 The 10000 times capacitance retention rate of the 5% MXene / ASAN composite electrode is shown.

[0009] The technical solutions of the present application are described below, and detailed embodiments and specific operation processes are given. It should be pointed out that for researchers in this technical field, a number of improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

[0010] Example 1 includes the following steps:

[0011] The preparation method of the multi-layer MXene is: indirect acid etching method to prepare MXene (Ti3AlC x ) First, add 30 mL of 9 mol / L hydrochloric acid to 10 mL of deionized water, then add 3.2 g of LiF, stir for 20 minutes until completely mixed. Then slowly add 2 g of Ti3AlC2 powder to the above solution in several times. At this time, a large amount of heat will be released, and the mixture solution is quickly placed at 35°C, stirred at a speed of 500 rpm for 48 h to etch off the aluminum atomic layer. After etching is completed, the precipitate is washed with deionized water several times until the PH is more than 6. Then centrifuge at 3500 rpm for 1 h, dry in a 60°C oven for 12 h, and finally obtain multi-layer Ti3AlC2.

[0012] Take 35 mL of deionized water, add 25 mg of MXene powder, stir for 20 minutes, then ultrasonic treatment for 30 minutes, to get a stable dispersion solution of MXene. Then add 4.2 mL of hydrochloric acid, add aniline and aniline o-methoxy-4-sulfonic acid monomer to the above solution according to the molar ratio of (9:1) to ensure that the monomer, oxidant and proton acid are all 1 mol / L in the system, and stir uniformly at room temperature. Take 1 mol / L of hydrochloric acid, add ammonium persulfate (APS) and stir for 10 minutes, then slowly add the ammonium persulfate solution to the MXene dispersion solution, and react for 12 h. Wash the solution with deionized water and ethanol respectively. Finally, dry the MXene / ASAN composite material containing 5% MXene doped at 60°C in an oven for 16 h. The composite material is recorded as 5% MXene / ASAN. According to the above steps, the composite material can be sequentially 3% MXene / ASAN respectively.

[0013] The electrode preparation method of 5% MXene / ASAN supercapacitor is as follows: take a certain amount of 5% MXene / ASAN 80 mg, carbon black 10 mg, and polytetrafluoroethylene (PVDF) 10 mg according to the mass ratio of 8:1:1 respectively. Mix in a mortar and grind uniformly, add an appropriate amount of N-methyl pyrrolidone (MBA), continue to grind to get a uniform mucilage, smear the mucilage on a 1 cm*4 cm carbon paper, and put it into an 80°C oven to dry for 12 h. After drying, control the load quality of each electrode to be 2 mg.

[0014] The prepared 5% MXene / ASAN composite electrode material can be used as the electrode of a supercapacitor for the actual manufacture of a supercapacitor.

Claims

1. This invention provides a conductive polymer (aniline and ortho-methoxyaniline monomers) and MXene (Ti3AlC) x The method for synthesizing and preparing composite supercapacitor electrodes is described in further detail below with reference to embodiments: 1) The preparation method of multilayer MXene is as follows: MXene (Ti3AlC) is prepared by indirect acid etching. x First, add 30 mL of 9 mol / L hydrochloric acid to 10 mL of deionized water, then add 3.2 g of LiF and stir for 20 minutes until completely mixed. Next, slowly add 2 g of Ti3AlC2 powder to the solution in several portions. This process releases a large amount of heat. Quickly place the mixture at 35°C and stir at 500 rpm for 48 hours to etch away the aluminum atomic layer. After etching, wash the precipitate several times with deionized water until the pH exceeds 6. Then centrifuge at 3500 rpm for 1 hour and dry in a 60°C oven for 12 hours to obtain multilayered Ti3AlC2. 2) The preparation method of 5% MXene / ASAN is as follows: Take 35 mL of deionized water, add 25 mg of MXene powder, stir for 20 minutes, and then sonicate for 30 minutes to obtain a stable dispersion of MXene. Then add 4.2 mL of hydrochloric acid, and add aniline and aniline o-methoxy-4-sulfonic acid monomers at a molar ratio of (9:1) to the above solution to ensure that the monomer, oxidant, and protic acid are all 1 mol / L in the system, and stir evenly at room temperature. Then take 1 mol / L hydrochloric acid, add ammonium persulfate (APS), stir for 10 minutes, and then slowly add the ammonium persulfate solution to the MXene dispersion solution, and react for 12 h. Wash the solution with deionized water and ethanol respectively. Finally, dry the MXene / ASAN composite material containing 3% MXene doping in an oven at 60 °C for 16 h. The composite material is recorded as 5% MXene / ASAN. According to the above steps, the composite material can be made of 5% MXene / ASAN in sequence. 3) The electrode preparation method for the 5% MXene / ASAN supercapacitor is as follows: Take a certain amount of 80mg of 5% MXene / ASAN, 10mg of carbon black, and 10mg of polytetrafluoroethylene (PVDF) in a mass ratio of 8:1:

1. Mix them in a mortar and grind them evenly. Add an appropriate amount of N-methylpyrrolidone (MBA) and continue grinding to obtain a uniform viscous liquid. Spread the viscous liquid on a 1cm*4cm piece of carbon paper and dry it in an 80℃ oven for 12 hours. After drying, remove the paper and control the loading mass of each electrode to be 2mg.

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