CN112768253B

CN112768253B - High-performance electrode material for super capacitor, preparation method of high-performance electrode material and super capacitor

Info

Publication number: CN112768253B
Application number: CN202011615547.4A
Authority: CN
Inventors: 李培
Original assignee: Zhongke Ma'anshan New Material Science Park Co ltd
Current assignee: Zhongke Ma'anshan New Material Science Park Co ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-22
Anticipated expiration: 2040-12-30
Also published as: CN112768253A

Abstract

The invention discloses a high-performance electrode material for a super capacitor, a preparation method of the high-performance electrode material and the super capacitor. The electrode material comprises MXene material and graphene material. According to the invention, the MXene material is modified by the graphene material to form the composite material, so that the flexibility of the material is increased due to the existence of the graphene, and the MXene material (such as Ti) is relieved₃C₂T_xMXene material) in the charge-discharge process, and increases the contact between the material and electrolyte, improves the conductivity of the material, and thus improves the electrochemical performance of the material.

Description

High-performance electrode material for super capacitor, preparation method of high-performance electrode material and super capacitor

Technical Field

The invention belongs to the field of new energy materials, and relates to a high-performance electrode material for a supercapacitor, a preparation method of the high-performance electrode material and the supercapacitor.

Background

The problems of continuous exhaustion of fossil fuels, environmental pollution and the like are increasingly serious nowadays, and efficient and environment-friendly alternative energy is urgently sought. Nowadays, the traditional lithium ion battery has become an indispensable part of human life, and provides power for the revolution of portable electronic products. However, for the applications such as electric vehicles and power grid storage with ever-expanding scale, the proliferation of electrochemical energy storage depends on the strict performance of the battery in the future, such as safety, energy density and cost requirements, which cannot be met by the performance of the conventional lithium ion battery. In view of these problems, in order to solve this problem, supercapacitors have received much attention due to their high safety, high energy density and long cycle life.

MXene material as a novel two-dimensional layered material is expected to be applied to the field of new energy, for example CN111029172A discloses Ti₃C₂T_xThe MXene material shell is used in the technical field of super capacitors, and further discloses a Ti-regulating and controlling material₃C₂T_xAlso disclosed in CN111763213A is a metal phthalocyanine-MXene composite material, a preparation method thereof, and a supercapacitor using the composite material, the preparation method 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 nanostructure, the MXene material and a second solvent to obtain the metal phthalocyanine-MXene composite material. But the specific capacity is lower and no relevant cycle performance study is carried out.

From the above, with Ti₃C₂T_xMXene material is an example, which has the advantages of high specific surface area and high electron transmission rate, and becomes a great research hotspot in the field of energy storage materials nowadays. But Ti₃C₂T_xMXene materials have poor mechanical properties resulting in short cycle life.

Therefore, it is necessary to provide a composite material based on MXene material, which has both high specific capacity and excellent cycling performance, so as to meet practical applications.

Disclosure of Invention

In view of the above problems in the prior art, the present invention aims to provide a high performance electrode material for a super capacitor, a preparation method thereof and a super capacitor.

The high-performance electrode material of the invention refers to: at 1A g^-1The specific capacity obtained by constant current charging and discharging under the current density of (2) is 226F g^-1Above, the capacity retention rate after 10000 times of circulation is more than 91%.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides an electrode material for a supercapacitor, where the electrode material includes an MXene material and a graphene material.

As a novel layered material, the MXene material has the advantages of high specific surface area and high electron transmission rate, and becomes a great research hotspot in the field of energy storage materials at present, but the MXene material has poor mechanical properties, is easy to break due to high brittleness, and has short cycle life.

Graphene is a carbon allotrope that typically has the characteristics of a two-dimensional crystal structure. Its carbon atom passing through sp²The hybridization orbitals and the pi-bonding compact surface regularly form a hexagonal honeycomb lattice structure with the thickness of only one atomic layer. The special crystal structure endows the graphene with excellent mechanical, thermal and electrical properties.

According to the invention, the MXene material is modified by the graphene material to form the composite material, and the flexibility of the material is improved by the grapheneRelieve MXene materials (such as Ti)₃C₂T_xMXene material) in the process of charging and discharging, and increases the contact between the material and electrolyte, improves the conductivity of the material, and improves the electrochemical performance of the material.

The following preferred technical solutions are not intended to limit the technical solutions provided by the present invention, and the technical objects and advantages of the present invention can be better achieved and achieved by the following preferred technical solutions.

Preferably, the MXene material is two-dimensional layered Ti₃C₂T_xMXene material.

Preferably, the graphene material includes at least one of graphene and reduced graphene oxide.

Preferably, the mass ratio of the MXene material to the graphene material is 1-99: 1, such as 1:1, 5:1, 8:1, 10:1, 15:1, 20:1, 25:1, 28:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1 or 90:1, and if the MXene material is too little and the graphene material is too much, the ion transmission performance is reduced; if the MXene material is too much and the graphene material is too little, the conductivity and the mechanical property are reduced, and the electrochemical property is further affected, preferably 1-50: 1, and more preferably 7-15: 1.

In a second aspect, the present invention provides a method for preparing an electrode material for a supercapacitor according to the first aspect, the method comprising the steps of:

(1) dissolving a graphene material and an MXene material in a solvent according to a formula amount to obtain a mixed solution;

(2) and carrying out hydrothermal reaction at 150-280 ℃ by adopting the mixed solution to obtain the electrode material for the supercapacitor.

The method is simple, has low requirements on equipment, and can prepare the electrode material with good electrochemical performance by one-step compounding.

In the method, the hydrothermal reaction is in a high-temperature high-pressure environment, the combination of the hydrothermal reaction and the porous material can be better realized within the temperature range of 150-280 ℃, a stable three-dimensional porous structure is formed, the ionic conduction is facilitated, and simultaneously, the good mechanical stability is considered, if the temperature is less than 150 ℃, the incomplete reaction can be caused, and the composite structure is unstable; if the temperature is higher than 280 ℃, the morphology of the material is affected, the specific surface area is reduced, and the efficient transmission of lithium ions is not facilitated.

As a preferred technical solution of the method of the present invention, the graphene material is at least one of graphene and reduced graphene oxide, and is preferably reduced graphene oxide. The reduced graphene oxide is obtained by reducing graphene oxide, and oxygen-containing functional groups on the graphene oxide are difficult to completely remove, so that the reduced graphene oxide and two-dimensional layered Ti are favorable for reduction₃C₂T_xMXene materials combine to form a more tightly bonded high performance composite.

Preferably, the MXene material is two-dimensional layered Ti₃C₂T_xMXene materials.

As a preferable technical scheme of the method, the two-dimensional layered Ti₃C₂T_xThe MXene material is prepared by the following method:

(a) mixing titanium powder, aluminum powder and graphite, ball milling, pressing into sheet, calcining at 1000-1800 deg.C (such as 1000 deg.C, 1100 deg.C, 1200 deg.C, 1250 deg.C, 1300 deg.C, 1400 deg.C, 1500 deg.C, 1600 deg.C, 1700 deg.C or 1800 deg.C) under the protection of protective gas, and grinding the calcined product to obtain polycrystalline MAX phase compound Ti₃AlC₂MXene powder;

(b) subjecting the Ti of step (a) to₃AlC₂MXene powder is dispersed in HF solution and stirred to react to obtain two-dimensional layered Ti₃C₂T_xMXene materials.

In the preferred technical scheme, a polycrystalline MAX phase compound Ti is synthesized₃AlC₂The calcining temperature of MXene powder is increased to 1000-1800 ℃, which is beneficial to improving crystallinity and structural stability, and the electrode material synthesized by adopting the MXene powder is used in a super capacitorWhen the material is applied in the medium, the stability of the charging and discharging process is improved.

Preferably, in the step (a), the titanium powder, the aluminum powder and the graphite are mixed according to an atomic ratio of Ti, Al and C of 3 (1.05-1.2): 2, such as 3:1.05:2, 3:1.1:2, 3:1.15:2 or 3:1.2: 2.

Preferably, the graphite of step (a) is flake graphite.

Preferably, the protective gas of step (a) comprises at least one of nitrogen, argon and helium.

Preferably, the calcination of step (a) is carried out for a time of 2h to 5h, such as 2h, 3h, 4h, 4.5h or 5h, etc.

Preferably, the concentration of the HF solution of step (b) is 20% to 60%, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, or the like.

Preferably, the stirring reaction time in the step (b) is 16h to 30h, such as 16h, 18h, 20h, 22h, 24h, 25h, 27h or 30 h.

Preferably, the stirring reaction of step (b) is followed by the steps of separating, washing and drying.

Preferably, the drying temperature is 50 ℃ to 100 ℃, such as 50 ℃, 60 ℃, 65 ℃, 70 ℃, 80 ℃, 90 ℃ or 100 ℃ and the like; the drying time is 10h to 15h, such as 10h, 11h, 11.5h, 12h, 13h or 15 h.

Preferably, the drying is vacuum drying at a vacuum of-70 Kpa to-90 Kpa, such as-70 Kpa, -75Kpa, -80Kpa or-90 Kpa, etc.

As a preferable technical scheme of the method, the solvent in the step (1) is water.

Preferably, the mixed solution is stirred for 1 to 2 hours, such as 1 hour, 1.2 hours, 1.5 hours, 1.8 hours or 2 hours before the hydrothermal reaction in step (2).

Preferably, the hydrothermal reaction time in step (2) is 15h to 25h, such as 15h, 16h, 18h, 19h, 20h, 22h, 23h, 24h or 25 h.

Preferably, the hydrothermal reaction in step (2) is followed by the steps of filtering, washing and drying.

Preferably, the washing employs reagents comprising water and ethanol.

Preferably, the drying is vacuum drying with a vacuum of-70 to-90 Kpa, such as-70 Kpa, -75Kpa, -80Kpa or-90 Kpa.

As a further preferred technical solution of the method of the present invention, the method comprises the steps of:

(1) preparation of reduced graphene oxide powder

Preparing a dispersed graphene aqueous solution by using graphite powder, reducing graphene oxide by using hydrogen peroxide to obtain reduced graphene oxide, and drying to obtain reduced graphene oxide powder;

(2) preparation of Ti₃C₂T_xMXene material

The method comprises the following steps: taking titanium powder, aluminum powder and graphite, and mixing the titanium powder, the aluminum powder and the graphite in an atomic ratio of Ti: al: c is uniformly mixed in a ratio of 3:1.1:2, and the mixture is ball-milled for 1 to 3 hours and then is pressed into a wafer under the pressure of 0.5 to 2 Gpa;

step two: putting the wafer pressed in the step one into a tube furnace, calcining for 2-5 h at 1000-1800 ℃ under the protection of inert gas, cooling to room temperature, taking out, grinding for 1h by using a mortar to obtain a polycrystalline MAX phase compound Ti₃AlC₂MXene powder;

step three: the Ti prepared in the second step₃AlC₂Dispersing MXene powder in an HF solution, and continuously stirring for 16-30 h at room temperature;

step four: after the reaction is finished, repeatedly washing the reaction product by deionized water, and centrifuging for 10 minutes at the rotating speed of 3800 rpm until the pH value of the supernatant is 6;

step five: vacuum drying the product washed in the fourth step at 50-100 ℃ for 10-15 h to obtain Ti3C2Tx MXene powder;

(3) preparation of electrode material for super capacitor

Step six:separately weighing Ti₃C₂T_xDissolving MXene powder and reduced graphene oxide powder in deionized water, continuously stirring for 1-2 h, transferring to a high-pressure reaction kettle, and continuously reacting for 15-25 h at 150-280 ℃;

step seven: filtering the product after the reaction in the sixth step, washing the product for 3 to 5 times by using pure water and ethanol, and finally drying the product for 10 to 15 hours in vacuum at the temperature of between 50 and 100 ℃ to obtain Ti₃C₂T_xMXene/reduced graphene oxide composite material, namely electrode material for a supercapacitor.

In a third aspect, the present invention provides a supercapacitor comprising the electrode material of the first aspect.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, the MXene material is modified by the graphene material to form the composite material, and the MXene material (such as Ti) is relieved by the graphene₃C₂T_xMXene material) in the process of charging and discharging, and increases the contact between the material and electrolyte, improves the conductivity of the material, and improves the electrochemical performance of the material.

(2) The method is simple, has low requirements on equipment, and can prepare the electrode material with good electrochemical performance by one-step compounding.

Drawings

FIG. 1 shows Ti prepared in example 1₃C₂T_xSEM pictures of MXene material;

FIG. 2 shows Ti prepared in example 1₃C₂T_xA specific capacity change diagram of the MXene/reduced graphene oxide composite material electrode under different current densities;

FIG. 3 shows Ti prepared in example 1₃C₂T_xCycle performance diagram of MXene/reduced graphene oxide composite material electrode.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

Example 1

The embodiment provides an electrode material for a supercapacitor and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

(1) 2g of graphite powder and 1g of NaNO were added in sequence in a 250mL beaker in an ice-water bath state₃And 46mLH₂SO₄And stirred well. Slowly adding 6g of potassium permanganate, controlling the temperature of the solution to be 20-50 ℃, keeping the temperature under the condition, continuously stirring for 5min, adding 92mL of water, continuously stirring for 15min, increasing the water temperature to about 98 ℃, adding 80mL of 30 wt% hydrogen peroxide at 60 ℃, centrifuging the liquid at the rotating speed of 7200r/min for 30min, and cleaning with hot water until the pH of the upper suspension is about 7. And dispersing the obtained powder into deionized water again, performing ultrasonic treatment for 15min, filtering, and drying to obtain the reduced graphene oxide.

(2) Titanium powder, aluminum powder and graphite are mixed according to the atomic ratio of Ti: al: mixing C in an atomic ratio of 3:1.1:2, ball milling for 1h, pressing the mixture into a disk shape, calcining at 1400 ℃ in a tube furnace in an argon atmosphere for 2h, cooling to room temperature, and grinding for 1h by using a mortar. Grinding Ti₃AlC₂Soaking the powder in 40 wt% HF solution, stirring at room temperature for 24 hr, repeatedly washing with deionized water after reaction, centrifuging at 3500r/min for 10min until the pH of the supernatant exceeds 6, and vacuum drying at 80 deg.C for 12 hr to obtain Ti₃C₂T_xMXene powder.

(3) 0.9g of Ti was weighed out separately by an electronic balance₃C₂T_xDissolving MXene material and 0.1g of reduced graphene oxide in 25mL of deionized water, magnetically stirring for 30min, transferring to a stainless steel high-pressure reaction kettle, standing at 210 ℃ for 18h, filtering a product after reaction, washing with pure water and ethanol for 3 times, and finally vacuum drying at 80 ℃ for 12h to obtain Ti₃C₂T_xMXene/reduced graphene oxide composite material (abbreviated as Ti)₃C₂T_x MXene/RGO)。

And (3) testing:

for Ti₃C₂T_xMorphology test is carried out on MXene/reduced graphene oxide composite material, and FIG. 1 shows Ti of the embodiment₃C₂T_xSEM pictures of MXene material.

Ti prepared as described above₃C₂T_xUniformly mixing MXene/reduced graphene oxide composite material, conductive carbon (SP) and PVDF in a mass ratio of 8:1:1, adding a proper amount of NMP, fully grinding, then coating the slurry on a foamed nickel current collector, carrying out vacuum drying for 12 hours at 45 ℃, respectively selecting a Pt electrode as a counter electrode, Hg/HgO as a reference electrode, and using 6M KOH solution as electrolyte. The charging and discharging voltage is-1.0V-0V and is 1A g^-1、2A g^-1、3A g^-1、4A g^-1、5A g^-1And 10A g^-1Constant current charging and discharging was carried out at a current density of 1, and the test results are shown in fig. 2, which is at 1A g^-1The specific capacity of the lower test can reach 242.3F g ^-110000 times of cycle performance is tested, the test result is shown in figure 3, after 10000 times of charge-discharge cycles, the capacity is still as high as 238.9F g^-1The retention rate reaches 98.6%, and excellent cycle stability is shown.

Example 2

The difference from example 1 is that Ti weighed in step (3)₃C₂T_xThe mass of MXene material and reduced graphene oxide were 0.95g and 0.05g, respectively, when Ti was present₃C₂T_xThe mass ratio of the MXene material to the reduced graphene oxide was 19.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1The specific capacity of the lower test can reach 226.1F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 91.4%.

Example 3

The difference from example 1 is that Ti weighed in step (3)₃C₂T_xThe mass of MXene material and reduced graphene oxide were 0.85g and 0.15g, respectively, at which time Ti₃C₂T_xMass ratio of MXene material to reduced graphene oxideIs 5.7.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1The specific capacity of the lower test can reach 232.8F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 93.7 percent.

As can be seen from a comparison between examples 1 to 3, Ti₃C₂T_xThe mass ratio of MXene material to graphene material is in a preferred range, and Ti₃C₂T_xWhen the mass ratio of the MXene material to the graphene material is within the range of 7-15: 1, higher specific capacity and better cycling stability can be obtained.

Example 4

The difference from example 1 is that the temperature of the reaction vessel in step (3) is 140 ℃.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1The specific capacity of the lower test can reach 217F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 93.1 percent.

Example 5

The difference from example 1 is that the temperature of the reaction vessel in step (3) is 300 ℃.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1The specific capacity of the lower test can reach 228F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 95.2 percent.

It can be seen from comparison between example 1 and examples 4-5 that there is a preferred range of the temperature of the hydrothermal reaction, and both too low and too high temperatures can affect the electrochemical performance of the electrode material, which may be because the difference of the hydrothermal temperature can affect the binding stability and morphology of the composite material.

Example 6

The difference from example 1 is that the calcination temperature in step (2) in a tube furnace under an argon atmosphere was 800 ℃.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1Specific volume of lower testThe amount can reach 201F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 91.4 percent.

It is understood from the comparison between example 1 and example 6 that too high a calcination temperature affects the crystallinity of the material, reduces the structural stability of the material, and further affects the structural collapse of the material during charge and discharge, thereby affecting the electrochemical performance.

Comparative example 1

The electrode material for a supercapacitor of this comparative example was Ti prepared in step (2) of example 1₃C₂T_xMXene powder, distinguished from example 1 by not being complexed with graphene oxide.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1The specific capacity of the lower test can reach 178.4F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 78.6 percent.

Comparative example 2

The electrode material for a supercapacitor of this comparative example was Ti prepared in step (2) of example 1₃C₂T_xMXene powder, the difference with example 1 is that the biological carbon material prepared by high temperature calcination of ginkgo leaves under inert atmosphere is compounded.

Capacitor assembly and same conditions testing was performed using the same method as example 1, which was at 1A g^-1The specific capacity of the lower test can reach 163.9F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 72.6 percent.

Comparative example 3

The electrode material for a supercapacitor of this comparative example was Ti prepared in step (2) of example 1₃C₂T_xMXene powder, the difference from example 1 is that the biocarbon material prepared by high temperature calcination of shrimp shells under inert atmosphere is compounded.

Capacitor assembly and same conditions testing was performed using the same method as in example 1, which was at 1A g^-1The specific capacity of the lower test can reach 180.1F g^-1(ii) a After 10000 times of charge-discharge cycles, the capacity retention rate reaches 79.6 percent.

As can be seen from the comparison between example 1 and comparative examples 1 to 3, the introduction of the carbon material in the form of graphene oxide is very important for obtaining a high-performance electrode material for a supercapacitor, and the excellent electrochemical performance of the present invention cannot be achieved unless graphene oxide is added to the raw material or replaced with another carbon source.

The applicant states that the present invention is illustrated by the above examples to show the detailed method of the present invention, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be carried out. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of the raw materials of the product of the present invention, and the addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. The electrode material for the super capacitor is characterized by comprising an MXene material and a graphene material, wherein the MXene material is two-dimensional layered Ti₃C₂T_xThe material comprises an MXene material, wherein the graphene material is reduced graphene oxide, and the mass ratio of the MXene material to the graphene material is 9: 1;

the electrode material for the supercapacitor is prepared by the following method, and the method comprises the following steps:

(1) dissolving a graphene material and an MXene material in a solvent according to a formula amount, wherein the graphene material is reduced graphene oxide, and the MXene material is two-dimensional layered Ti₃C₂T_xMXene material, wherein the solvent is water to obtain a mixed solution;

the reduced graphene oxide is prepared according to the following method: preparing a dispersed graphene aqueous solution by using graphite powder, reducing graphene oxide by using hydrogen peroxide to obtain reduced graphene oxide, and drying to obtain reduced graphene oxide powder;

(2) and carrying out hydrothermal reaction for 18h at 210 ℃ by adopting the mixed solution to obtain the electrode material for the supercapacitor.

2. A method for preparing the electrode material for the supercapacitor according to claim 1, comprising the steps of:

(2) and carrying out hydrothermal reaction at 210 ℃ for 18h by using the mixed solution to obtain the electrode material for the supercapacitor.

3. The method of claim 2, wherein the two-dimensional layered Ti₃C₂T_xThe MXene material is prepared by the following method:

(a) mixing titanium powder, aluminum powder and graphite, pressing into sheets after ball milling, calcining at 1000-1800 ℃ under the protection of protective gas, grinding the calcined product to obtain a polycrystalline MAX phase compound Ti₃AlC₂MXene powder;

(b) subjecting the Ti of step (a) to₃AlC₂MXene powder is dispersed in HF solution and stirred for reaction to obtain two-dimensional layered Ti₃C₂T_xMXene materials.

4. The method according to claim 3, wherein in the step (a), the titanium powder, the aluminum powder and the graphite are mixed in an atomic ratio of Ti, Al and C of 3 (1.05-1.2): 2.

5. The method of claim 3, wherein the graphite of step (a) is flake graphite.

6. The method of claim 3, wherein the protective gas of step (a) comprises at least one of nitrogen, argon, and helium.

7. The method of claim 3, wherein the calcination of step (a) is carried out for a time period of 2 to 5 hours.

8. The method according to claim 3, wherein the concentration of the HF solution in the step (b) is 20 to 60%.

9. The method of claim 3, wherein the stirring reaction time in step (b) is 16-30 h.

10. The method of claim 3, wherein the stirring reaction of step (b) is followed by the steps of separating, washing and drying.

11. The method according to claim 10, wherein the drying temperature is 50 ℃ to 100 ℃ and the drying time is 10h to 15 h.

12. The method of claim 10, wherein the drying is vacuum drying at a vacuum level of-70 Kpa to-90 Kpa.

13. The method according to claim 2, wherein the mixed solution is stirred for 1 to 2 hours before the hydrothermal reaction in step (2).

14. The method according to claim 2, wherein the hydrothermal reaction of step (2) is followed by the steps of filtering, washing and drying.

15. The method of claim 14, wherein the washing employs reagents comprising water and ethanol.

16. The method according to claim 14, wherein the drying temperature is 50 ℃ to 100 ℃ and the drying time is 10h to 15 h.

17. The method of claim 14, wherein the drying is vacuum drying at a vacuum level of-70 Kpa to-90 Kpa.

18. Method according to claim 2, characterized in that it comprises the following steps:

(1) preparation of reduced graphene oxide powder

(2) preparation of Ti₃C₂T_xMXene material

The method comprises the following steps: taking titanium powder, aluminum powder and graphite, and mixing the titanium powder, the aluminum powder and the graphite in an atomic ratio of Ti: al: uniformly mixing C-3: 1.1:2, ball-milling for 1-3 h, and pressing under the pressure of 0.5-2 Gpa to prepare a wafer;

step three: ti prepared in the second step₃AlC₂Dispersing MXene powder in an HF solution, and continuously stirring for 16-30 h at room temperature;

(3) preparation of electrode material for super capacitor

Step six: are respectively provided withWeighing Ti₃C₂T_xDissolving MXene powder and reduced graphene oxide powder in deionized water, continuously stirring for 1-2 h, transferring to a high-pressure reaction kettle, and continuously reacting for 18h at 210 ℃;

19. A supercapacitor, characterized in that it comprises an electrode material according to claim 1.