阅读说明：本技术 金属酞菁-MXene复合材料、超级电容器及其制备方法 (Metal phthalocyanine-MXene composite material, supercapacitor and preparation method of supercapacitor ) 是由 许宗祥 李敏章 于 2020-06-01 设计创作，主要内容包括：本发明公开了金属酞菁-MXene复合材料及其制备方法和应用。其中,制备金属酞菁-MXene复合材料的方法包括：(1)将金属酞菁与第一溶剂混合,得到金属酞菁溶液；将所述金属酞菁溶液加入到水中,得到金属酞菁纳米结构；(2)将所述金属酞菁纳米结构、MXene材料与第二溶剂混合,得到所述金属酞菁-MXene复合材料。该方法工艺过程简单且重复性好,所采用的材料合成简易、价格低廉、易于规模制备,有利于实现材料及器件的商业化。通过采用该方法,可以在MXene层之间引入金属酞菁纳米结构充当层间间隔物,从而有效防止MXene的重新堆叠效应,增加MXene表面上的电化学活性位点,对于电化学氧化还原过程中的离子迁移率也有显著增强效果,进而可以改善对电荷存储的电化学响应。(The invention discloses a metal phthalocyanine-MXene composite material and a preparation method and application thereof. The method for preparing the metal phthalocyanine-MXene composite material comprises the following steps: (1) mixing metal phthalocyanine with a first solvent to obtain a metal phthalocyanine solution; adding the metal phthalocyanine solution into water to obtain a metal phthalocyanine nano-structure; (2) and mixing the metal phthalocyanine nano-structure, the MXene material and a second solvent to obtain the metal phthalocyanine-MXene composite material. The method has the advantages of simple process and good repeatability, and the adopted materials are easy to synthesize, low in price and easy to prepare on a large scale, thereby being beneficial to realizing commercialization of materials and devices. By adopting the method, the metal phthalocyanine nano structure can be introduced between the MXene layers to serve as an interlayer spacer, so that the re-stacking effect of the MXene is effectively prevented, the electrochemical active sites on the MXene surface are increased, the ion mobility in the electrochemical redox process is obviously enhanced, and the electrochemical response to charge storage can be improved.)

1. A method for preparing a metal phthalocyanine-MXene composite material, comprising:

(1) mixing metal phthalocyanine with a first solvent to obtain a metal phthalocyanine solution; adding the metal phthalocyanine solution into water to obtain a metal phthalocyanine nano-structure;

(2) and mixing the metal phthalocyanine nano-structure, the MXene material and a second solvent to obtain the metal phthalocyanine-MXene composite material.

2. The method according to claim 1, wherein the metal phthalocyanine is at least one selected from the group consisting of a compound represented by formula (a), a compound represented by formula (b), and a compound represented by formula (c),

wherein M is Fe, Co, Ni, Cu, Zn, Mn or Pb.

3. The method of claim 1, wherein the first solvent is selected from at least one of concentrated sulfuric acid, methanesulfonic acid, and formic acid.

4. The method according to claim 1, wherein the concentration of the metal phthalocyanine in the metal phthalocyanine solution is 0.5-10 mg/mL;

optionally, in the step of adding the metal phthalocyanine solution into water, the adding rate of the metal phthalocyanine solution is 0.5-5 mL/min;

optionally, the mass ratio of the metal phthalocyanine nanostructure to the MXene material is 1 (1-10).

5. The method according to claim 1, wherein the second solvent is selected from at least one of methanol, ethanol, chlorobenzene, dichlorobenzene, and toluene.

6. A metal phthalocyanine-MXene composite material, characterized by being prepared by the method of any one of claims 1 to 5.

7. A supercapacitor, comprising a working electrode, the working electrode comprising:

a working electrode substrate;

an electrode material layer formed on at least a part of a surface of the working electrode substrate, the electrode material layer comprising: the metal phthalocyanine-MXene composite of claim 6 and a conductive agent.

8. The supercapacitor according to claim 7, wherein the mass ratio of the metal phthalocyanine-MXene composite material to the conductive agent is (10-5): 1;

optionally, the working electrode substrate is selected from at least one of carbon paper, carbon cloth, foamed nickel;

optionally, the conductive agent is carbon black.

9. A method of making the working electrode of the supercapacitor of claim 7 or 8, comprising:

(1) mixing the metal phthalocyanine-MXene composite material and the conductive agent according to a preset ratio, and dispersing the mixture in an ethanol solution of perfluorosulfonic acid to obtain electrode material slurry;

(2) and applying the electrode material slurry to at least part of the surface of the working electrode substrate to obtain the working electrode of the supercapacitor.

10. The method according to claim 9, wherein the mass fraction of the perfluorosulfonic acid in the ethanol solution of the perfluorosulfonic acid is 1 to 10%.

Technical Field

The invention relates to the field of electrochemistry, in particular to a metal phthalocyanine-MXene composite material and a preparation method thereof, and a super capacitor applying the metal phthalocyanine-MXene composite material and a preparation method thereof.

Background

Due to the increasing world population, the consumption of various energy sources has led to a gradual reduction in non-renewable energy sources. Electrochemical energy storage devices, especially supercapacitors (also called electrochemical capacitors), are ideal choices for many applications such as electric vehicles, power sectors, portable electronic products, and the like, and have the characteristics of long cycle life, high power density, high energy density, good temperature characteristics, environmental friendliness, and the like. Therefore, researchers have focused on finding new candidate materials for high performance energy storage and conversion devices.

In recent years, metal-based phthalocyanines (metal-based phthalocyanines) have received much attention in electrochemical applications, such as supercapacitors, sensors, and the like. The metal phthalocyanine is an organic semiconductor compound with a chemical structure consisting of four isoindole units, the structure of the metal phthalocyanine is greatly adjustable, and different peripheral or non-peripheral substituent groups are introduced or central metal is changed to enable the metal phthalocyanine to have different properties. The interaction of the phthalocyanine ring with the metal center can improve the transport rate of carriers, so that the carriers can show excellent physicochemical properties such as high charge mobility and redox characteristics in energy storage and energy conversion systems. Currently, only a few metal-based phthalocyanines are used as electrode materials for electrochemical capacitors, including nickel, copper, iron, and cobalt. Among them, octamethyl-substituted metal phthalocyanines and their related derivatives are chemically and thermally stable electrode materials, and exhibit excellent cycling stability in symmetric supercapacitors. However, the relatively low conductivity of the metal phthalocyanine material reduces the electron transport rate in the redox process, so that the prepared capacitor has low specific capacitance and energy density, thereby limiting the practical application of the metal phthalocyanine material. One of the methods to enhance the redox properties of metal phthalocyanine electrode materials is to compound with conductive materials such as carbon nanotubes or two-dimensional (2D) graphene, and recently developed transition metal carbides (MXene). However, the existing MXene materials still remain to be improved.

Disclosure of Invention

The present invention is based on the discovery by the inventors of the following facts and problems:

MXene is a new class of two-dimensional transition metal carbides with electrical conductivity that has attracted considerable attention from researchers in a variety of applications. MXene has surface hydrophilicity, high electrical conductivity, excellent mechanical properties and flexibility, and is therefore considered as a promising candidate material for replacing carbon materials, particularly graphene for electrochemical energy storage, for practical applications including supercapacitors and metal-ion batteries, among others. However, similar to graphene, MXene sheets are highly susceptible to stacking and aggregation due to strong van der waals interactions between layers, which may limit electrolyte ion penetration into the gaps between MXene layers, ultimately resulting in degradation of the electrochemical performance of the device.

Further, the inventors found through intensive studies that the incorporation of nanoparticle-like interlayer spacers between MXene layers can effectively prevent the re-stacking effect and can increase electrochemically active sites on the MXene surface. The metal phthalocyanine has an 18-pi aromatic electron cloud, can coordinate with MXene easily through pi-pi interaction and improves the electrochemical response to charge storage. By adding the one-dimensional nanostructure of the metal phthalocyanine material into the MXene sheet, the ionic mobility in the electrochemical redox process is obviously enhanced. Therefore, the screening and optimization of the metal phthalocyanine material and the preparation of the metal phthalocyanine material and MXene composite material are one of the development directions of the high-performance super capacitor in the future. The development of economic and efficient devices is a must way for realizing the sustainable development of the industry of the super capacitor and benefiting the future of human beings.

In view of the above, in one aspect of the present invention, the present invention provides a method for preparing a metal phthalocyanine-MXene composite material. According to an embodiment of the invention, the method comprises: (1) mixing metal phthalocyanine with a first solvent to obtain a metal phthalocyanine solution; adding the metal phthalocyanine solution into water to obtain a metal phthalocyanine nano-structure; (2) and mixing the metal phthalocyanine nano-structure, the MXene material and a second solvent to obtain the metal phthalocyanine-MXene composite material.

According to the method for preparing the metal phthalocyanine-MXene composite material, the technical process is simple, the repeatability is good, the adopted material is simple to synthesize, low in price and easy to prepare in a large scale, and commercialization of materials and devices is facilitated. By adopting the method provided by the invention, the metal phthalocyanine nano structure can be introduced between the MXene layers to serve as an interlayer spacer, so that the re-stacking effect of MXene is effectively prevented, the electrochemical active sites on the MXene surface are increased, the ion mobility in the electrochemical redox process is obviously enhanced, and the electrochemical response to charge storage can be improved. The super capacitor prepared by applying the composite material as an electrode material shows higher mass specific capacitance, and still shows higher energy density and capacitance retention rate after 20000 cycles. The experimental result shows that the metal phthalocyanine-MXene composite material can be used as an electrode material in a future high-performance super capacitor.

In addition, the method for preparing the metal phthalocyanine-MXene composite material according to the above embodiment of the present invention may further have the following additional technical features:

in some embodiments of the invention, the metal phthalocyanine is selected from the group consisting of a compound of formula (a) (ortho metal phthalocyanine MPc), a compound of formula (b) (non-peripheral octamethyl-substituted metal phthalocyanine N-MMe₂Pc) and a compound represented by the formula (c) (metal phthalocyanine MMe substituted by octamethyl at the periphery)₂Pc).

Wherein M is Fe, Co, Ni, Cu, Zn, Mn or Pb.

In some embodiments of the invention, the first solvent is selected from at least one of concentrated sulfuric acid, methanesulfonic acid, formic acid.

In some embodiments of the present invention, the concentration of the metal phthalocyanine in the metal phthalocyanine solution is 0.5-10 mg/mL.

In some embodiments of the invention, in the step of adding the metal phthalocyanine solution into water, the adding rate of the metal phthalocyanine solution is 0.5-5 mL/min.

In some embodiments of the invention, the mass ratio of the metal phthalocyanine nanostructure to the MXene material is 1 (1-10).

In some embodiments of the present invention, the second solvent is selected from at least one of methanol, ethanol, chlorobenzene, dichlorobenzene, toluene.

In another aspect of the present invention, the present invention provides a metal phthalocyanine-MXene composite material. According to the embodiment of the invention, the metal phthalocyanine-MXene composite material is prepared by the method for preparing the metal phthalocyanine-MXene composite material of the embodiment. Therefore, in the metal phthalocyanine-MXene composite material, the metal phthalocyanine nano structure is introduced between MXene layers to serve as an interlayer spacer, so that the re-stacking effect of MXene can be effectively prevented, the electrochemical active sites on the MXene surface are increased, the ion mobility in the electrochemical redox process is remarkably enhanced, and the electrochemical response to charge storage can be improved. The super capacitor prepared by applying the composite material as an electrode material shows higher mass specific capacitance, and still shows higher energy density and capacitance retention rate after 20000 cycles. The experimental result shows that the metal phthalocyanine-MXene composite material can be used as an electrode material in a future high-performance super capacitor.

In yet another aspect of the present invention, a supercapacitor is presented. According to an embodiment of the invention, the supercapacitor comprises a working electrode comprising: a working electrode substrate; an electrode material layer formed on at least a part of a surface of the working electrode substrate, the electrode material layer comprising: the metal phthalocyanine-MXene composite and the conductive agent of the above example. The super capacitor shows higher mass specific capacitance by adopting the metal phthalocyanine-MXene composite material of the embodiment, and still shows higher energy density and capacitance retention rate after 20000 cycles.

In addition, the super capacitor according to the above embodiment of the present invention may also have the following additional technical features:

in some embodiments of the invention, the mass ratio of the metal phthalocyanine-MXene composite material to the conductive agent is (10-5): 1.

In some embodiments of the invention, the working electrode substrate is selected from at least one of carbon paper, carbon cloth, nickel foam.

In some embodiments of the invention, the conductive agent is carbon black.

In yet another aspect of the invention, the invention provides a method for preparing the working electrode of the supercapacitor of the above embodiment. According to an embodiment of the invention, the method comprises: (1) mixing the metal phthalocyanine-MXene composite material and the conductive agent according to a preset ratio, and dispersing the mixture in an ethanol solution of perfluorosulfonic acid to obtain electrode material slurry; (2) and applying the electrode material slurry to at least part of the surface of the working electrode substrate to obtain the working electrode of the supercapacitor.

In addition, the method for manufacturing the supercapacitor according to the above embodiment of the present invention may further have the following additional technical features:

in some embodiments of the invention, the predetermined ratio is: the mass ratio of the metal phthalocyanine-MXene composite material to the conductive agent is (10-5): 1.

In some embodiments of the present invention, the mass fraction of the perfluorosulfonic acid in the ethanol solution of the perfluorosulfonic acid is 1 to 10%.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a TEM image of copper phthalocyanine (CuPc) nanorods;

FIG. 2 is a peripheral octamethyl nickel phthalocyanine (NiMe)₂Pc) TEM images of nanowires;

fig. 3 is an SEM image of MXene;

FIG. 4 is N-CuMe₂SEM image of Pc-MXene composite (M10P 2);

FIG. 5 is MXene, N-CuMe₂XRD patterns of Pc and M10P2 composite materials;

FIG. 6 shows the response test results of cyclic voltammetry for different electrode materials, wherein a is N-CuMe₂Pc, b is MXene, c is M10P1, d is M10P2, e is M10P4, f is a linear plot of the logarithm (i) and the logarithm (v);

FIG. 7 is a constant current discharge curve for different electrode materials at different current densities, where a is N-CuMe₂Pc and b are MXene, c is M10P1, d is M10P2, e is M10P4, and f is the relation between the specific capacitance and the current density of the electrode;

FIG. 8 shows the performance test results of a symmetrical supercapacitor made of M10P2, where a is the cyclic voltammetry response and b is the constant current discharge curve;

fig. 9 shows the performance test results of the symmetrical supercapacitor made of M10P2, where a is the capacity retention and coulomb efficiency of the M10P2 symmetrical supercapacitor at 20000 cycles, where a is the first 10 cycles of the charge-discharge curve set symmetrically in fig. 1, and a is the last 10 cycles of the charge-discharge curve in fig. 2; b is a Nyquist diagram of the electrode in the frequency range of 1-105 Hz, and c is a baud diagram of the M10P2 symmetrical super capacitor.

Detailed Description

The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available, for example, concentrated sulfuric acid may be a commercially available concentrated sulfuric acid product.

The material characterization means used in the present invention includes that the X-ray diffraction pattern (XRD) is radiation with Cu-K α

Collected by X-ray diffractometer (RigakuSmartlab); the prepared samples were analyzed for morphology and elemental profile using scanning electron microscopy (SEM, Zeiss Merlin) and transmission electron microscopy (TEM, Tecnai F30); recording the raman spectra by horribeladram HR Evolution; of elements in composite materialsChemical states were identified by X-ray photoelectron spectroscopy (XPS, ESCALB 250 Xi); the surface area of the sample was measured by Brunauer-Emmett-Teller (BET-ASAP 2020).

Unless otherwise specified, all electrochemical measurements of the invention on supercapacitors were carried out at room temperature using an electrochemical analyzer (CHI 660E workstation), Ag/AgCl and Pt electrodes being used as reference and counter electrodes, respectively, at 1MH₂SO₄Cyclic Voltammetry (CV) and constant current charge and discharge (GCD) studies were performed in the electrolyte solution.

In one aspect of the invention, the invention provides a method for preparing a metal phthalocyanine-MXene composite material. According to an embodiment of the invention, the method comprises: (1) mixing metal phthalocyanine with a first solvent to obtain a metal phthalocyanine solution; adding the metal phthalocyanine solution into water to obtain a metal phthalocyanine nano-structure; (2) and mixing the metal phthalocyanine nano-structure, the MXene material and a second solvent to obtain the metal phthalocyanine-MXene composite material.

The method for preparing the metal phthalocyanine-MXene composite according to the embodiment of the present invention is further described in detail below.

(1) Mixing metal phthalocyanine with a first solvent to obtain a metal phthalocyanine solution; and adding the metal phthalocyanine solution into water to obtain the metal phthalocyanine nano-structure.

According to some embodiments of the invention, the metal phthalocyanine is selected from the group consisting of a compound of formula (a) (ortho metal phthalocyanine MPc), a compound of formula (b) (non-peripheral octamethyl-substituted metal phthalocyanine N-MMe₂Pc) and a compound represented by the formula (c) (metal phthalocyanine MMe substituted by octamethyl at the periphery)₂Pc).

Wherein M is Fe, Co, Ni, Cu, Zn, Mn or Pb.

The specific type of the MXene material is not particularly limited, and MXene materials commonly used in the art may be used. Specifically, MXenes materials are a class of two-dimensional inorganic compounds in material science. Such materials consist of a transition metal carbide, nitride or carbonitride of several atomic layer thicknesses. According to some embodiments of the invention, MXene materials used in the present invention may be Ti3C2-MXenes, Nb4C3-MXenes, V4C3-MXenes, Mo2TiC2-MXenes, Ti2N-Mxenes, Nb2C-MXenes, etc.

According to some embodiments of the present invention, the first solvent may be at least one selected from concentrated sulfuric acid, methanesulfonic acid, and formic acid. Such a solvent can disperse the metal phthalocyanine well, thereby obtaining a stable and uniform metal phthalocyanine solution.

According to some embodiments of the present invention, in the metal phthalocyanine solution, the concentration of the metal phthalocyanine may be 0.5 to 10mg/mL, such as 0.5mg/mL, 1mg/mL, 1.5mg/mL, 2mg/mL, 5mg/mL, 8mg/mL, 10mg/mL, or the like. Therefore, the metal phthalocyanine solution has proper concentration and is more convenient for process operation.

According to some embodiments of the present invention, in the step of adding the metal phthalocyanine solution to water, the metal phthalocyanine solution may be added at a rate of 0.5 to 5mL/min, such as 0.5mL/min, 1mL/min, 1.5mL/min, 2mL/min, 2.5mL/min, 3mL/min, 4mL/min, 5mL/min, or the like. The inventor finds in research that the specific morphology of the metal phthalocyanine nanostructure in the product can be regulated and controlled by controlling the adding rate of the metal phthalocyanine solution in the step. Within a certain range, the slower the addition rate of the metal phthalocyanine solution, the more the product tends to form nano-structures with uniform morphology. Depending on the specific metal phthalocyanine material, the formed nanostructures may be nanorods, nanowires, or nanodots.

(2) And mixing the metal phthalocyanine nano-structure, the MXene material and a second solvent to obtain the metal phthalocyanine-MXene composite material. Specifically, after the metal phthalocyanine nano-structure, the MXene material and the second solvent are mixed and fully reacted under the condition of continuous stirring, the obtained product can be subjected to heat treatment to completely evaporate the solvent in the product, and then the product is dried to obtain the metal phthalocyanine-MXene composite material product.

According to some embodiments of the present invention, the mass ratio of the metal phthalocyanine nanostructure to the MXene material may be 1 (1-10), such as 1:1, 1:2, 1:5, 1:6, 1:8, 1:10, and the like. The inventor finds in research that in the metal phthalocyanine-MXene composite material, the electrode conductivity is weakened due to excessively high metal phthalocyanine nanostructure incorporation, so that the performance of a supercapacitor using the composite material as an electrode active substance is reduced; and if the doping amount of the metal phthalocyanine nanostructure is too low, the re-stacking effect of MXene sheets cannot be effectively prevented, and the performance of the supercapacitor is also reduced.

According to some embodiments of the present invention, the second solvent may be at least one selected from methanol, ethanol, chlorobenzene, dichlorobenzene and toluene. The solvent can well disperse the metal phthalocyanine nano-structure and MXene materials, and is further favorable for the insertion of the metal phthalocyanine nano-structure into the interlayer of MXene.

In another aspect of the present invention, the present invention provides a metal phthalocyanine-MXene composite material. According to the embodiment of the invention, the metal phthalocyanine-MXene composite material is prepared by the method for preparing the metal phthalocyanine-MXene composite material of the embodiment. Therefore, in the metal phthalocyanine-MXene composite material, the metal phthalocyanine nano structure is introduced between MXene layers to serve as an interlayer spacer, so that the re-stacking effect of MXene can be effectively prevented, the electrochemical active sites on the MXene surface are increased, the ion mobility in the electrochemical redox process is remarkably enhanced, and the electrochemical response to charge storage can be improved. The super capacitor prepared by applying the composite material as an electrode material shows higher mass specific capacitance, and still shows higher energy density and capacitance retention rate after 20000 cycles. The experimental result shows that the metal phthalocyanine-MXene composite material can be used as an electrode material in a future high-performance super capacitor.

In addition, it should be noted that all the advantages of the features described above for the method for preparing the metal phthalocyanine-MXene composite material are also applicable to the metal phthalocyanine-MXene composite material product, and are not described in detail herein.

In yet another aspect of the present invention, a supercapacitor is presented. According to an embodiment of the invention, the supercapacitor comprises a working electrode comprising: a working electrode substrate; an electrode material layer formed on at least a part of a surface of the working electrode substrate, the electrode material layer comprising: the metal phthalocyanine-MXene composite and the conductive agent of the above example. Thus, the super capacitor has all the features and advantages described above for the metal phthalocyanine-MXene composite material, and the description thereof is omitted. In summary, the super capacitor shows higher mass specific capacitance by using the metal phthalocyanine-MXene composite material of the above embodiment, and still shows higher energy density and capacitance retention rate after 20000 cycles.

According to some embodiments of the invention, the mass ratio of the metal phthalocyanine-MXene composite material to the conductive agent may be (10-5: 1), for example, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, and the like. Thereby, the electrochemical performance of the supercapacitor can be further improved.

The specific kind of the working electrode substrate is not particularly limited, and can be selected by those skilled in the art according to actual needs. According to some embodiments of the present invention, the working electrode substrate may be selected from at least one of carbon paper, carbon cloth, and nickel foam.

The specific kind of the conductive agent is not particularly limited, and can be selected by those skilled in the art according to actual needs. According to some embodiments of the invention, the conductive agent is carbon black.

In yet another aspect of the invention, the invention provides a method for preparing the working electrode of the supercapacitor of the above embodiment. According to an embodiment of the invention, the method comprises: (1) mixing a metal phthalocyanine-MXene composite material and a conductive agent according to a preset ratio, and dispersing the mixture in an ethanol solution of perfluorosulfonic acid to obtain electrode material slurry; (2) and applying electrode material slurry to at least part of the surface of the working electrode substrate to obtain the working electrode of the supercapacitor. Specifically, the metal phthalocyanine-MXene composite material and the conductive agent can be mixed and ground according to a predetermined ratio, and dispersed in an ethanol solution of perfluorosulfonic acid to obtain electrode material slurry; then spreading the electrode material slurry on a working electrode substrate by a doctor blade method, and drying to obtain the working of the supercapacitorAnd an electrode. In some embodiments, the mass difference between the working electrode substrate and the dried working electrode (i.e., the total effective mass of the electrode) is in the range of 0.5 to 5mg/cm²In the meantime.

According to some embodiments of the invention, the predetermined ratio is: the mass ratio of the metal phthalocyanine-MXene composite material to the conductive agent is (10-5): 1, such as 10:1, 9:1, 8:1, 7:1, 6:1, 5:1 and the like. Thereby, the electrochemical performance of the supercapacitor can be further improved.

According to some embodiments of the present invention, in the ethanol solution of perfluorosulfonic acid, the mass fraction of perfluorosulfonic acid may be 1 to 10%, for example, 1%, 3%, 5%, 8%, 10%, etc. In the ethanol solution, the perfluorosulfonic acid can function as a binder, and the adhesion between the electrode material and the electrode base material can be further improved by controlling the mass fraction of the perfluorosulfonic acid within the above range.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way. In addition, MXene material used in the following specific examples is Ti3C 2.