1, 5-naphthalene disulfonic acid modified polypyrrole / MXene composite material as well as in-situ preparation method and application thereof

Abstract

The invention discloses a 1, 5-naphthalene disulfonic acid modified polypyrrole / MXene composite material as well as an in-situ preparation method and application thereof. A pyrrole monomer, 1, 5-naphthalene disulfonic acid and an MXene colloidal solution are uniformly mixed and are prepared by a one-step in-situ polymerization method. Under the condition that the current density is 0.5 A / g, the specific capacitance of polypyrrole is 151F / g, while the specific capacitance of the 1, 5-naphthalene disulfonic acid modified polypyrrole / MXene composite material is as high as 714F / g, and compared with polypyrrole, the specific capacitance is increased by 4.7 times. The capacity retention rate of polypyrrole is only 33.5% after 5000 times of circulation, while the capacity retention rate of a symmetric supercapacitor assembled by the composite material is as high as 99.8% after 10000 times of circulation, compared with polypyrrole, the composite material shows excellent circulation stability, and the problems of low specific capacitance and poor circulation stability of the existing conductive polymer are effectively improved.

Description

Technical Field

[0001] This invention relates to a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material, its in-situ preparation method and application, and belongs to the field of composite materials. Background Technology

[0002] In recent years, with the rapid development of smart electronics technology, there has been tremendous commercial interest in flexible, portable, and wearable devices. Extensive research has been conducted to meet the growing demand for next-generation energy storage systems. Supercapacitors, a type of energy storage device, are promising due to their superior power density, significantly shorter charging time, and extremely long cycle life. The fundamental goal in developing such devices is to simultaneously achieve high energy and high power density. Currently, supercapacitors still fall short in energy density, limiting their widespread application in scenarios requiring high energy output. Furthermore, their relatively low energy density and low cycle efficiency restrict further use. In addition, polymer electrode materials are prone to aggregation during the composite process, reducing the effective active area and affecting charge transport efficiency. The compatibility between the electrode and electrolyte, interfacial charge transfer kinetics, and the mechanical stability of the material during cycling are also critical issues that urgently need to be addressed. Therefore, developing composite electrode materials with high energy density, excellent cycle stability, and efficient interfacial charge transport has become an important direction for promoting the development of supercapacitor technology. Polypyrrole conductive polymers possess excellent properties, enabling efficient and reversible Faraday redox reactions. Due to their ease of synthesis, environmental sustainability, tunable conductivity, significant redox activity, and outstanding charge storage and transport capabilities, they have become a strong candidate material for high-performance supercapacitor electrodes.

[0003] Polypyrrole (PP) holds a unique position in the field of supercapacitors, being a typical conjugated conductive polymer. PPP possesses multiple oxidation states, which change during doping and dedoping processes, enabling charge storage and release. It can also store charge through rapid redox reactions and exhibits excellent environmental stability, remaining relatively stable in air and resistant to oxidation or degradation. Currently, PPP can be synthesized through electrochemical or chemical oxidative polymerization of pyrrole monomers. However, the relatively limited effective surface area of ​​PPP restricts the rapid transport of electrolyte ions and reduces the availability of electroactive sites, leading to structural degradation and volume expansion during long-term cycling, resulting in poor cycle stability and specific capacity. Summary of the Invention

[0004] Objectives of this invention: The first objective is to provide a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material to address the problems of volume shrinkage and expansion, and poor long-cycle stability of current conductive polymer materials. The second objective is to provide a method for in-situ preparation of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene electrode composite material. The third objective is to provide an electrode sheet prepared using this 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material. The final objective is to provide the application of this 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material or the electrode sheet in symmetrical supercapacitors.

[0005] Technical solution: The present invention provides a method for in-situ preparation of 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite materials, comprising the following steps:

[0006] MXene colloidal solution was added to a mixed solution containing pyrrole monomer and 1,5-naphthalene disulfonic acid. The solution was then slowly added dropwise to a ferric chloride hexahydrate solution and polymerized in situ under an ice-water bath. After centrifugation, washing, and vacuum drying, the 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite material was obtained.

[0007] Further, the concentration of the MXene colloidal solution is 1~10 mg / mL, the molar ratio of pyrrole monomer to 1,5-naphthalene disulfonic acid is 1:0.03~1:0.1, and the mass of MXene accounts for 0.5%~5% of the mass of pyrrole monomer. Preferably, the molar ratio of pyrrole monomer to 1,5-naphthalene disulfonic acid is 1:0.05~1:0.1, and the mass of MXene accounts for 1~3% of the mass of pyrrole monomer. Most preferably, the molar ratio of pyrrole monomer to 1,5-naphthalene disulfonic acid is 1:0.05, and the mass of MXene accounts for 1% of the mass of pyrrole monomer. The concentration of the ferric chloride hexahydrate solution is 0.2~0.8 mmol / L, the in-situ polymerization time is 3~6 h, the vacuum drying time is 12~24 h, and the vacuum drying temperature is 20~60 °C.

[0008] The 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material obtained by the preparation method described in this invention.

[0009] An electrode sheet is prepared using the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material described in this invention.

[0010] Further, the 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite material was mixed with acetylene black and polyvinylidene fluoride, and dissolved in N-methylpyrrolidone to obtain a slurry. The slurry was uniformly coated on graphite paper and vacuum dried to obtain an electrode sheet. The mass ratio of the 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite material to acetylene black and polyvinylidene fluoride was 6~8:1~2:0.5~1.

[0011] The present invention also includes a symmetrical supercapacitor comprising the 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite material described in the present invention or the electrode sheet described in the present invention.

[0012] Furthermore, the electrode sheet containing the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material described in this invention is used as the cathode and anode, respectively, and H2SO4 solution is used as the electrolyte to assemble a symmetrical supercapacitor.

[0013] The 1,5-naphthalene disulfonic acid modified polypyrrole / MXene composite material of this invention is produced by in-situ polymerization of 1,5-naphthalene disulfonic acid as a dopant and crosslinking agent with two-dimensional MXene and pyrrole monomers under the action of ferric chloride hexahydrate initiator. The 1,5-naphthalene disulfonic acid, as a crosslinking agent, contains two sulfonic acid groups. Acidic conditions favor the protonation of pyrrole monomers, releasing H₂ during the reaction. ＋ This makes it easier for oxidants to oxidize, thereby improving the efficiency of chain initiation and chain growth. The sulfonate group at one end of 1,5-naphthalenedisulfonic acid is doped into the polypyrrole chain, with its rigid naphthalene ring supporting the chain structure and optimizing the electron transport rate. The sulfonate group at the other end is anchored to the MXene surface, allowing the MXene conductive framework to directly and firmly bind to the polypyrrole. This suppresses volume expansion while constructing a high-speed electron transport network, thus synergistically achieving high specific capacitance and long cycle life. In other words, protonation doping of the polypyrrole chain is achieved simultaneously during polymerization, while two-dimensional MXene material is introduced as a conductive framework. The inherent metallic conductivity of MXene provides the conductive polymer with a high-speed electron transport "framework," and the rigid layered structure has excellent mechanical strength and cycle stability, effectively limiting the volume expansion and contraction of the conductive polymer and preventing structural collapse. This results in conductive polymers with higher energy storage performance and cycle stability.

[0014] This invention achieves integrated in-situ composite by controlling the ratio of pyrrole monomer, 1,5-naphthalene disulfonic acid, and MXene colloidal solution. The aim is to optimize the interfacial bonding and component synergistic effects among polypyrrole, 1,5-naphthalene disulfonic acid, and two-dimensional MXene nanosheets. Through ratio control, a composite material with adjustable components was prepared, and the optimal MXene ratio (1:0.05 molar ratio of pyrrole monomer to 1,5-naphthalene disulfonic acid, with MXene accounting for 1% of the pyrrole monomer mass) was determined to achieve optimal charge transport and structural stability. The sulfonic acid groups of 1,5-naphthalene disulfonic acid provide reactive sites for polypyrrole, accelerating electron transfer. The π-π interaction between 1,5-naphthalene disulfonic acid and MXene enhances the stability of the composite material, contributing to improved overall electrode cycle stability and specific capacity.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages;

[0016] (1) This invention prepares 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite materials in situ. The introduction of 1,5-naphthalene disulfonic acid and MXene significantly optimizes the performance of 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene nanocomposites through multiple synergistic effects. The sulfonic acid groups abundant in the 1,5-naphthalene disulfonic acid molecule can efficiently bind to the oxidized polypyrrole chain through coulomb-driven electrostatic interaction and embed as a dopant into the polymer backbone to balance charge and stabilize the conductive structure. During polymerization, the sulfonic acid groups can form hydrogen bonds with the -NH- groups on the polypyrrole chain, further enhancing the stability of the doping. The disulfonic acid group structure in 1,5-naphthalene disulfonic acid can bind to the oxygen-containing functional groups on the MXene surface and also bind to the doping and bonding of polypyrrole, ultimately constructing a stable π-π interaction structure. This interfacial bridging effect not only establishes an efficient interfacial charge transport channel but also effectively confines the volume expansion of polypyrrole during charge and discharge, fundamentally improving the cycle stability and specific capacitance of the electrode.

[0017] (2) The present invention provides an in-situ preparation of 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene electrode composite material. This involves a one-step in-situ polymerization method that simultaneously reacts pyrrole monomer, 1,5-naphthalenedisulfonic acid, and MXene solution, resulting in a uniform composite of the three components at the nanoscale. The process is simple, highly controllable, and easily scalable. Furthermore, this electrode composite material exhibits a large specific capacitance, providing 714 F / g at 0.5 A / g. When the working electrode is assembled into a symmetrical supercapacitor for long-cycle charge-discharge testing, the results show that after 10,000 cycles, the capacity retention rate is 99.8% of the initial value. Therefore, the 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene nanocomposite material possesses excellent cycling performance.

[0018] (3) This invention uses 1,5-naphthalenedisulfonic acid as an acidic dopant, providing a synthetic route that does not require the use of highly hazardous and volatile inorganic strong acids. Its stable properties make the polymerization process easier to control, which is in line with the concept of green development.

[0019] (4) This invention provides a synergistic optimization of material synthesis process and performance, which to some extent changes the problem that it is difficult to balance conductivity, stability and process complexity of conductive polymer materials. At the same time, pyrrole monomers are inexpensive and can be polymerized in aqueous phase by oxidants, without the need for synthesis in organic solvents or under more stringent conditions. Attached Figure Description

[0020] Figure 1 Scanning electron microscope image of the in-situ prepared 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite material obtained in Example 3;

[0021] Figure 2Cyclic voltammetry curves of the in-situ prepared 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene electrode composite material obtained in Example 3 at different scan rates;

[0022] Figure 3 The galvanostatic charge-discharge curves of the in-situ prepared 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene electrode composite material obtained in Example 3 under different galvanostatic current densities are shown.

[0023] Figure 4 The constant current charge-discharge curves of the electrode composite materials provided in Examples 2-6 at a current density of 0.5 A / g are shown.

[0024] Figure 5 The galvanostatic charge-discharge curves of the composite materials obtained in Comparative Examples 1-2 and Examples 9-10 at a current density of 0.5 A / g;

[0025] Figure 6 The cycling stability curve of the symmetrical supercapacitor assembled from the in-situ prepared 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene electrode composite material provided in Example 3 at a current density of 2 A / g. Detailed Implementation

[0026] Example 1

[0027] The preparation of MXene colloidal solution was carried out according to the steps of Example 1 in CN119965219A (1): MXene was prepared by etching Ti3AlC2 using conventional methods to obtain an MXene colloidal solution with a concentration of 3 mg / mL.

[0028] Example 2

[0029] (1) In-situ preparation of 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite material

[0030] First, 17.3 g of ferric chloride hexahydrate was dissolved in 80 mL of deionized water and magnetically stirred until completely dissolved to prepare a 0.8 mmol / L ferric chloride hexahydrate solution. Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.0216 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 3.66 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.0216 mol / L 1,5-naphthalenedisulfonic acid and 15 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. The molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid tetrahydrate was 1:0.1, and the mass of MXene accounted for 3% of the mass of pyrrole monomer. Under stirring in an ice-water bath, the well-mixed solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 hours. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60°C for 12 hours. The final product was a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

[0031] Example 3

[0032] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0033] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 2.58 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid and 5 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. The molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.05, and the mass of MXene accounted for 1% of the mass of pyrrole monomer. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 h. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60°C for 12 h. The final product was a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

[0034] Scanning electron microscopy analysis was performed on the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material obtained in this embodiment, and the results are as follows: Figure 1 As shown. Figure 1The images show scanning electron microscope (SEM) images of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material obtained in Example 2, where (a) is a low-magnification (1 μm) SEM image and (b) is a high-magnification (200 nm) SEM image. Figure 1 It is evident that the 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite forms a hierarchical structure with sheet-like support for nanoparticles. The two-dimensional sheets of MXene in the composite material provide a continuous and highly conductive substrate, while the uniform and fine nanoparticles of the 1,5-naphthalene disulfonic acid-modified polypyrrole are tightly anchored on the sheet surface. This not only retains the highly active surface of the 1,5-naphthalene disulfonic acid-modified polypyrrole particles, but also constructs a conductive network and framework through the MXene sheets, greatly improving the charge transport capability and structural stability.

[0035] Example 4

[0036] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0037] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.0324 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 4.74 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.0324 mol / L 1,5-naphthalenedisulfonic acid and 25 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. The molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.15, and the mass of MXene accounted for 5% of the mass of pyrrole monomer. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 hours. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60°C for 12 hours. The final product was a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

[0038] Example 5

[0039] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0040] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.00648 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 2.14 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.00648 mol / L 1,5-naphthalenedisulfonic acid and 2.5 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. The molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.03, and the mass of MXene accounted for 0.5% of the mass of pyrrole monomer. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 hours. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60°C for 12 hours. The final product was a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

[0041] Example 6

[0042] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0043] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.00216 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 1.71 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.00216 mol / L 1,5-naphthalenedisulfonic acid and 1 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. The molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.01, and the mass of MXene accounted for 0.2% of the mass of pyrrole monomer. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 hours. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60°C for 12 hours. The final product was a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

[0044] Example 7

[0045] The 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material prepared in Example 3 was used to prepare a composite material. The specific steps are as follows:

[0046] Weigh 8 mg of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material sample prepared in Example 3, 1 mg of acetylene black, and 1 mg of polyvinylidene fluoride, and mix them. Grind the mixture evenly in a mortar, then add N-methylpyrrolidone dropwise and continue grinding the mixture until a slurry with a certain viscosity and fluidity is formed. The amount of N-methylpyrrolidone used is 0.1-0.3 L. Use a spatula to evenly coat the mixed slurry on a 1 cm thick surface. -2 The working electrode was prepared by vacuum drying at 60°C for 12 hours on a graphite paper substrate.

[0047] Electrodes were prepared using the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite materials obtained in Examples 2-6, respectively, using the methods described above.

[0048] Five sets of three-electrode electrochemical testing systems were constructed, using the composite material electrode sheet obtained above as the working electrode, a platinum sheet electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and a 1 mol / L sulfuric acid solution as the electrolyte.

[0049] Cyclic voltammetry and constant current charge-discharge tests were performed at room temperature, with a voltage range of -0.2 to 0.8 V, a scan rate range of 10 to 100 mV / s, and a current density range of 0.5 to 5 A / g. The results are as follows: Figure 2 , 3 As shown.

[0050] Figure 2 The cyclic voltammetry curves of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene electrode composite material obtained in Example 3 at different scan rates are shown below. Figure 2 It can be seen that the CV curve has redox peaks, indicating that the 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite material obtained in Example 3 has pseudocapacitive behavior. Furthermore, as the scan rate increases, the area of ​​the CV curve also increases significantly without significant deformation, indicating that the composite material has excellent electron transport rate performance.

[0051] Figure 3 The graphs shown are galvanostatic charge-discharge curves of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material in Example 3 at different current densities. Figure 3 It can be seen that the galvanostatic charge-discharge curves of the composite electrode prepared by 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material at different current densities are derived from... Figure 3As can be seen, under different current densities, the GCD curve of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material in Example 3 shows a specific capacitance of 714 F / g at 0.5 A / g. Compared with the specific capacitance of polypyrrole at 0.5 A / g (151 F / g), the specific capacitance of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material is increased by 4.7 times. This is mainly because the sulfonic acid groups of 1,5-naphthalenedisulfonic acid interact electrostatically with polypyrrole, providing more active sites. MXene, as a conductive backbone, promotes electron transfer between molecular chains, thereby increasing the electron transfer rate.

[0052] Figure 4 The graphs show the galvanostatic charge-discharge curves of the composite electrodes prepared from the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite materials in Examples 2-6 at a current density of 0.5 A / g. Figure 4 As shown, when the current density is 0.5 A / g, the electrode composite material provided in Example 2 has a specific capacitance of 602 F / g, the composite electrode provided in Example 3 has a specific capacitance of 714 F / g, the composite electrode provided in Example 4 has a specific capacitance of 427 F / g, the composite electrode provided in Example 5 has a specific capacitance of 433 F / g, and the composite electrode provided in Example 6 has a specific capacitance of 360 F / g. Figure 4 It is evident that when the molar ratio of pyrrole monomer to 1,5-naphthalene disulfonic acid is 1:0.05, and the mass of MXene accounts for 1% of the mass of pyrrole monomer, the prepared 1,5-naphthalene disulfonic acid modified polypyrrole / MXene electrode composite material exhibits the highest specific capacitance.

[0053] Example 8

[0054] Assembly and testing of 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene symmetric supercapacitors

[0055] As shown in the results of Example 7 above, the composite working electrode prepared in Example 3 has the highest specific capacity. Therefore, the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material obtained in Example 3, with a pyrrole monomer to 1,5-naphthalenedisulfonic acid molar ratio of 1:0.05 and MXene mass accounting for 1% of the pyrrole monomer mass, was selected as the working electrode cathode and anode, respectively. A 1 mol / L sulfuric acid solution was used as the electrolyte to assemble a symmetrical supercapacitor. The electrochemical performance of the symmetrical supercapacitor assembled based on this electrode material in sulfuric acid electrolyte was studied and tested. The results are as follows: Figure 6The results show that the device assembled from the composite material prepared in Example 3 retained 99.8% of its initial capacity after 10,000 charge-discharge cycles at a current density of 2 A / g, demonstrating stable cycle performance. Polypyrrole, after 5,000 charge-discharge cycles at 2 A / g, retained only 33.5% of its initial capacity. The composite material prepared in Comparative Example 1 retained only 61% of its initial capacity after 10,000 charge-discharge cycles at 2 A / g. This indicates that the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material exhibits excellent cycle stability.

[0056] Comparative Example 1

[0057] Compared with Example 3, this comparative example provides a polypyrrole / MXene composite material, which is prepared in the same way as Example 3, except that 1,5-naphthalenedisulfonic acid is not added, and other optimal conditions are the same as in Example 3.

[0058] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0059] The concentration of the pyrrole monomer solution was 0.216 mol / L, and the mass of MXene accounted for 1% of the mass of the pyrrole monomer.

[0060] A 0.216 mol / L pyrrole monomer solution (1.5 mL) was ultrasonically dispersed with 5 mL of the MXene colloidal solution prepared in Example 1, and then the mixture was stirred until homogeneous. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 h. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60 °C for 12 h. The final product was a polypyrrole / MXene composite material.

[0061] The polypyrrole / MXene composite material prepared in this comparative example was used to prepare a working electrode according to Example 7, and constant current charge-discharge tests were performed in a three-electrode system, using the same method as in Example 7. When the current density was 0.5 A / g, the 1,5-naphthalenedisulfonic acid modified polypyrrole composite working electrode had a specific capacity of 323 F / g. Figure 5 As shown.

[0062] Comparative Example 2

[0063] Compared with Example 3, this comparative example provides a 1,5-naphthalenedisulfonic acid modified polypyrrole composite material, the preparation process of which is the same as that of Example 3, except that MXene is not added, and other optimal conditions are the same as those of Example 3.

[0064] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0065] The concentration of the pyrrole monomer solution was 0.216 mol / L, and the molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.05.

[0066] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid. 2.58 mL of this mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid was slowly added dropwise over 30 minutes in an ice-water bath with stirring. The reaction was allowed to proceed for 3 h. After the reaction was complete, the solution was centrifuged and filtered to collect a black precipitate. The black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60 °C for 12 h. This yielded a 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

[0067] The 1,5-naphthalenedisulfonic acid-modified polypyrrole composite material prepared in this comparative example was used to prepare a working electrode according to Example 7. A constant current charge-discharge test was performed in a three-electrode system, using the same method as in Example 7. When the current density was 0.5 A / g, the 1,5-naphthalenedisulfonic acid-modified polypyrrole composite material working electrode exhibited a specific capacity of 237 F / g. Figure 5 As shown.

[0068] Example 9

[0069] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0070] The concentration of the pyrrole monomer solution was 0.216 mol / L, the molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.05, the mass of MXene accounted for 0.05% of the mass of pyrrole monomer, and other optimal conditions were the same as in Example 3.

[0071] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 2.58 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid and 0.25 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 h. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60 °C for 12 h. Finally, 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material was obtained.

[0072] The working electrode was prepared using the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material described in this embodiment, and constant current charge-discharge tests were performed in a three-electrode system, using the same method as in Example 7. When the current density was 0.5 A / g, the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material working electrode exhibited a specific capacity of 287 F / g. Figure 5 As shown.

[0073] Example 10

[0074] The preparation of the ferric chloride hexahydrate solution is the same as in Example 2.

[0075] The concentration of the pyrrole monomer solution was 0.216 mol / L, the molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid was 1:0.05, the mass of MXene accounted for 10% of the mass of pyrrole monomer, and other optimal conditions were the same as in Example 3.

[0076] Pyrrole monomer and 1,5-naphthalenedisulfonic acid were dispersed in deionized water to obtain a mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid. Then, MXene colloidal solution was added. 2.58 mL of the mixed solution containing 0.216 mol / L pyrrole monomer and 0.0108 mol / L 1,5-naphthalenedisulfonic acid and 50 mL of the MXene colloidal solution prepared in Example 1 were ultrasonically dispersed, and then the mixture was stirred until homogeneous. Under stirring in an ice-water bath, the homogeneous solution was slowly added dropwise over 30 minutes to a single-necked flask containing ferric chloride hexahydrate solution, and the reaction was allowed to proceed for 3 h. After the reaction was complete, the solution was centrifuged and filtered to collect the black precipitate. The obtained black precipitate was transferred to a vacuum drying oven and dried under vacuum at 60 °C for 12 h. Finally, 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material was obtained.

[0077] The working electrode was prepared using the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material described in this embodiment. Constant current charge-discharge testing was performed in a three-electrode system, following the same method as in Example 7. When the current density was 0.5 A / g, the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material working electrode exhibited a specific capacity of 338 F / g. Figure 5 As shown.

[0078] As the above analysis shows, the specific capacitance of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material prepared in this invention is much greater than that of the polypyrrole / MXene composite material and the 1,5-naphthalenedisulfonic acid-modified polypyrrole composite material. The amount of MXene added must be strictly limited within the range required by this invention. Exceeding this range will lead to a significant decrease in the specific capacitance of the 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material.

Claims

1. A method for in-situ preparation of 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite materials, characterized in that, Includes the following steps: MXene colloidal solution was added to a mixed solution containing pyrrole monomer and 1,5-naphthalene disulfonic acid. The solution was then slowly added dropwise to a ferric chloride hexahydrate solution and polymerized in situ under an ice-water bath. After centrifugation, washing, and vacuum drying, the 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite material was obtained.

2. The preparation method according to claim 1, characterized in that, The concentration of MXene colloidal solution is 1~10 mg / mL, the molar ratio of pyrrole monomer to 1,5-naphthalenedisulfonic acid is 1:0.03~1:0.1, and the mass of MXene accounts for 0.5%~5% of the mass of pyrrole monomer.

3. The preparation method according to claim 1, characterized in that, The concentration of the ferric chloride hexahydrate solution was 0.2 ~ 0.8 mmol / L, and the in-situ polymerization time was 3 ~ 6 h.

4. The preparation method according to claim 1, characterized in that, The vacuum drying time is 12~24h, and the vacuum drying temperature is 20~60℃.

5. The 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite material obtained by the preparation method according to any one of claims 1-4.

6. An electrode sheet, characterized in that, The polypyrrole / MXene composite material was prepared using the 1,5-naphthalenedisulfonic acid modified polypyrrole / MXene composite material as described in claim 5.

7. The electrode sheet according to claim 6, characterized in that, A 1,5-naphthalene disulfonic acid-modified polypyrrole / MXene composite material was mixed with acetylene black and polyvinylidene fluoride and dissolved in N-methylpyrrolidone to obtain a slurry. The slurry was uniformly coated on graphite paper and vacuum dried to obtain an electrode sheet.

8. The electrode sheet according to claim 7, characterized in that, The mass ratio of 1,5-naphthalene disulfonic acid modified polypyrrole / MXene composite material to acetylene black and polyvinylidene fluoride is 6~8:1~2:0.5~1.

9. A symmetrical supercapacitor, characterized in that, It includes the electrode sheet as described in claim 5 or any one of claims 6-8.

10. The symmetrical supercapacitor according to claim 9, characterized in that, Electrode sheets containing 1,5-naphthalenedisulfonic acid-modified polypyrrole / MXene composite material were used as the cathode and anode, respectively, and H2SO4 solution was used as the electrolyte to assemble a symmetrical supercapacitor.

Images