N-doped NH4 + Method for preparing intercalated MXene material and applications thereof

Abstract

This invention belongs to the field of functional materials technology, specifically relating to an N-doped NH4 + Preparation method and application of intercalated MXene materials. The preparation method includes: etching MAX phase (Ti3AlC2) powder in situ using HF acid (generated in situ with NH4F and concentrated hydrochloric acid), centrifuging to remove the acid, and then treating the MXene with ammonia to generate NH4F. + Intercalation. After centrifugal washing, the MXene slurry is placed in a tube furnace and heated in a vacuum environment at 1–15°C for s. ‑1 The temperature was increased to 400–700 °C at a heating rate, and then held at that temperature for 2–10 minutes to obtain N-doped NH4. + Intercalated MXene materials. This method effectively avoids the oxidation problem of MXene, realizes the feasible preparation of active electrode materials for high-rate supercapacitors, and the material exhibits superior capacity and rate performance.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically relating to an N-doped NH4 + Preparation methods and applications of intercalated MXene materials. Background Technology

[0002] Electrochemical energy storage plays a crucial role in developing new energy technologies and promoting the achievement of national dual-carbon goals. Active electrode materials, as key materials in supercapacitors, determine the main performance of the device. Two-dimensional transition metal carbide / nitride materials (MXene) possess advantages such as tunable composition, controllable surface chemistry, strong hydrophilicity, and numerous active sites. Therefore, their application as active electrode materials in supercapacitors holds great promise.

[0003] However, MXene-based supercapacitors still face numerous challenges in practical applications. For instance, due to van der Waals forces and hydrogen bonds, MXene sheets are prone to self-stacking; and the -F functional groups generated after liquid-phase etching exhibit electrochemical inertness. These issues lead to a sharp reduction in the number of active sites in MXene, hindering ion transport and ultimately resulting in a significant deterioration in device performance. Based on structural engineering principles, focusing on heterostructure construction, interlayer structure, and surface structure modulation holds promise for improving MXene self-stacking, promoting ion transport, increasing the number of surface active sites, and enhancing the electrochemical performance of electrodes and devices based on MXene.

[0004] MXene surface modification can be achieved through surface functional group modulation, such as functional group removal and substitution, the introduction of specific functional groups, and the adsorption and intercalation of molecules on the surface and interlayer sites of MXene sheets based on hydrogen bonding and cross-linking. In addition, surface atomic doping is also a very effective surface modification method. Changes in the surface chemical properties of MXene can significantly modulate the surface charge state, increase the number of active sites, and affect the hydrophilic and hydrophobic properties of the sheet surface, as well as the resulting distribution of water molecules and interlayer spacing. However, synergistically achieving MXene interlayer ion intercalation and surface modification remains quite challenging due to the significant process deviations between these two optimization methods. Furthermore, it is also limited by the inherent susceptibility of MXene materials to oxidation. Summary of the Invention

[0005] To address the problem of MXene's drastic reduction in active sites and difficulty in ion transport due to self-stacking, this invention proposes an N-doped NH4... + A thermal shock fabrication method for intercalated MXene (using Ti3C2 as an example of MXene material) is described, along with examples of its application in supercapacitors. Using etched multilayer MXene as a precursor, NH4 is employed... +Intercalation into the MXene interlayer, combined with rapid annealing, utilizes the ions and water molecules in the MXene interlayer under wet slurry as thermal shock agents to prepare N-doped NH4. + Intercalation of MXene. This method effectively avoids the oxidation problem of MXene by introducing NH4 into the partially retained interlayer. + Based on ions, surface N doping was achieved, simultaneously modifying surface functional groups and regulating interlayer structure. Then, using this material as the active material, the active electrode of a high-rate supercapacitor was fabricated, demonstrating superior capacity and rate performance.

[0006] To achieve the objective of this invention, the technical solution adopted is: N-doped NH4 + The preparation method of intercalated MXene materials includes the following steps:

[0007] (1) MAX phase etching: Ti3AlC2 (MAX phase) powder was etched with HF acid generated by in-situ reaction of ammonium fluoride (NH4F) and concentrated hydrochloric acid. After centrifugation and cleaning, the etched product MXene (Ti3C2T) was obtained. x ).

[0008] Specifically, the concentrated hydrochloric acid has a mass fraction of 37%, and 0.015–0.08 g of NH4F is used per milliliter of concentrated hydrochloric acid. -1 Concentrated hydrochloric acid.

[0009] The mass ratio of MAX phase powder to NH4F is 1:1.6. The MAX phase powder is slowly added to the etching solution in 5 to 6 batches. The etching process is to stir at 40°C for 18 to 60 hours.

[0010] The centrifugation cleaning method is as follows: control the rotation speed at 3000-10000 rpm and the centrifugation time at 5-20 min. After centrifugation, remove the supernatant liquid, add ultrapure water and shake to redisperse the centrifuged precipitate. Repeat the centrifugation-redispersion process until the pH of the solution is 6.

[0011] (2)NH4 + Intercalation treatment: Ammonia was added to the above MXene dispersion for intercalation treatment, while removing byproducts generated during etching. After intercalation, the solution was washed with ammonia and then centrifuged to remove the supernatant until the final solution had a pH of approximately 8, yielding NH4. + Intercalated MXene slurry.

[0012] Specifically, the initial mass ratio of MAX phase powder to ammonia water is controlled to be 1:1 to 6, and the mixture is stirred at room temperature for 3 to 6 hours after adding ammonia water.

[0013] Control the centrifuge speed to 4000–10000 rpm (centrifugation time is generally 10 min). After centrifugation, remove the supernatant, add ammonia water and shake to disperse the precipitate, then centrifuge again. Repeat this process 3–6 times to complete the washing. After centrifugation and washing, collect the precipitate and transfer it to a ceramic boat.

[0014] (3) N-doped NH4 + Preparation of intercalated MXene: The above NH4 + The intercalated MXene slurry was placed in a tube furnace, rapidly heated under vacuum, and then held at that temperature for a certain period of time. The furnace was then cooled rapidly using circulating water, resulting in rapidly annealed N-doped NH4. + Intercalation MXene.

[0015] Specifically, the annealing conditions are: 1–15°C in a tube furnace. -1 The temperature is increased to 400–700℃ at a rate of [missing information], and after the heating is completed, it is held at that temperature for 2–10 minutes. Then, the tube furnace body is cooled using circulating water to obtain N-doped NH4. + Intercalated MXene material.

[0016] Circulating water cooling can keep the tubular furnace at 15-20°C / min. -1 After 20-30 minutes of cooling, the tube furnace can be cooled to room temperature.

[0017] Preparation of active electrode: The N-doped NH4 obtained by the above method is used... + Intercalated MXene materials are used as active materials to prepare electrodes for use in supercapacitors.

[0018] Specifically, the preparation method of the active electrode includes: mixing the obtained MXene material with activated carbon and polytetrafluoroethylene (PTFE, used in the form of a 1 wt% aqueous dispersion) at a mass ratio of 8:1:1, then adding 10-30 mL of anhydrous ethanol and sonicating in an ice bath for 5-30 min to ensure uniform dispersion. The mixture is then vacuum dried at 40-50°C, and the dried sample is rolled to a surface loading of 1-6 mg / cm². -2 The electrode sheet, after being cut, serves as the active electrode of the supercapacitor.

[0019] Compared with the prior art, the present invention achieves the following beneficial effects: MAX phase is etched using HF acid generated in situ with hydrochloric acid and NH4F to obtain multilayer MXene, and NH4F… + Embedded between MXene layers, followed by rapid annealing, to allow NH4 to escape from the layers. +The residual moisture rapidly sublimates to produce gas. This gas cannot escape quickly within the confined space between the MXene layers, generating instantaneous high pressure that causes thermal shock to the MXene layers. Simultaneously, N-doping is performed on the material at high temperature. Because the rapid annealing process is short, the prepared MXene material retains a large number of electrochemically inert -F groups while preserving the interlayer hydrophilic groups, thus maintaining the material's hydrophilicity. It also partially retains the NH4 introduced into the interlayer. + Based on this, surface N doping was achieved, thereby obtaining N-doped NH4. + Intercalated MXene materials. Simultaneous surface functional group modification and interlayer structure regulation were achieved, effectively shortening ion transport distance and accelerating ion transport, while also exposing more active sites, thereby effectively improving the electrochemical performance of supercapacitor electrodes based on them. Attached Figure Description

[0020] Figure 1 It is MAX powder, MXene powder etched by NH4F and hydrochloric acid in Example 1, NH4 + N-doped NH4 obtained after intercalation of MXene and rapid annealing for 5 minutes + XRD characterization of intercalated MXene.

[0021] Figure 2 The left side shows the MXene powder obtained by etching in step 1 of Example 1 and the N-doped NH4 obtained after rapid annealing for 5 minutes. + SEM characterization of intercalated MXene powder (right).

[0022] Figure 3 It is via NH4 + Infrared (FT-IR) spectra of MXene materials after intercalation and rapid annealing at different times.

[0023] Figure 4 The N-doped NH4 was obtained after rapid annealing for 5 minutes. + Fine spectral peaking results of N1s in X-ray photoelectron spectroscopy (XPS) analysis of intercalated MXene.

[0024] Figure 5 It is N-doped NH4 + A performance comparison chart of intercalated MXene and MXene (unmodified MXene) obtained by etching in step 1 of Example 1 as supercapacitor electrode materials. The left chart shows the performance of the two materials at 10 mV s. -1 Cyclic voltammetry curves at different scan rates; the right figure shows the voltammetry curves of the two materials at 2A g. -1 Constant current charge-discharge curves at current density.

[0025] Figure 6 This is a performance comparison graph of MXene materials obtained by rapid annealing for different times; where 'a' represents the performance of the three materials at 10 mV s. -1 Cyclic voltammetry curves at scan rate, b represents the three materials at 2A g. -1 The constant current charge-discharge curves at different current densities, where c represents the specific capacitance of pure MXene and MXene obtained by rapid annealing for different times at different current densities.

[0026] Figure 7 It is N-doped NH4 + XRD characterization images of intercalated MXene, HF-etched MXene, and n-butylamine-intercalated MXene.

[0027] Figure 8 This is a performance comparison chart of MXene prepared at different heating rates during annealing as electrode materials for supercapacitors. The left chart shows the performance of MXene prepared at different heating rates at 10 mV / s. -1 Cyclic voltammetry curves at different scan rates; the right figure shows MXene prepared at different heating rates at 2A g. -1 Constant current charge-discharge curves at current density.

[0028] Figure 9 This is a performance comparison chart of MXene prepared by ammonia intercalation with different amounts of ammonia water as electrode materials for supercapacitors. The left chart shows the performance of MXene prepared by ammonia intercalation with different amounts of ammonia water at 10 mV s⁻¹. -1 Cyclic voltammetry curves at different scan rates; the right figure shows MXene prepared by intercalation with different amounts of ammonia at 2A g. -1 Constant current charge-discharge curves at current density. Detailed Implementation

[0029] This invention is not limited to the specific implementation methods listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0030] Example 1

[0031] Step 1: MAX Phase Etching: Weigh 4.8g of NH4F powder, measure 60mL of concentrated hydrochloric acid, and add it to a PTFE beaker. Stir for 30min to dissolve the NH4F powder and prepare the etching solution. Weigh 3g of MAX phase powder and slowly add it to the etching solution in 5 batches. Stir at 40℃ for 48h to etch the MAX phase. After etching, centrifuge the etching solution at high speed to remove the supernatant acid. Then add ultrapure water to redisperse the solution, centrifuge again, and dilute again. Repeat the centrifugation and dilution process until the pH of the solution reaches 6. Specifically, the high-speed centrifugation cleaning method is as follows: control the rotation speed at 8000rpm and the centrifugation time at 10min.

[0032] Step 2: NH4 + Intercalation treatment: Add ammonia to the solution after centrifugation and washing in step 1 for intercalation treatment. Control the initial mass ratio of MAX phase to ammonia to be 1:3. Stir at room temperature for 6 hours to remove byproducts generated during the etching process. After intercalation, centrifuge to remove the supernatant, add ammonia again and shake to redisperse the precipitate. Centrifuge again and repeat this process several times until the pH of the final solution is approximately 8. Control the centrifugation speed at 8000 rpm and the centrifugation time at 5 minutes.

[0033] Step 3: N-doping NH4 + Preparation of intercalated MXene: The above NH4 + After intercalation, the MXene slurry was transferred into a quartz boat, placed in a tube furnace, and heated in a vacuum environment at 10°C for s. -1 The temperature was rapidly increased to 500℃, held for 5 minutes after heating, and then the furnace was cooled using circulating water to accelerate cooling. Once cooled to room temperature, the powder was removed from the quartz boat, yielding rapidly annealed N-doped NH4. + Intercalation MXene.

[0034] Step 4: Preparation of the active electrode: Take 16 mg of MXene powder, 2 mg of activated carbon, and 0.2 g of 1 wt% PTFE solution obtained in Step 3 and add them to a beaker. Then add 5 mL of anhydrous ethanol and sonicate in an ice bath for 20 min to disperse them evenly. Then place it in a vacuum drying oven and dry at 40 °C for 12 h. Roll the dried sample to a surface loading of 2 mg / cm². -2 Electrode sheets were cut to a certain size and used as active electrodes for supercapacitors. Their electrochemical performance was studied in a three-electrode system.

[0035] Example 2

[0036] (1) First, prepare NH4 + Intercalated MXene slurry. Method is the same as in Example 1.

[0037] (2) Next, prepare N-doped NH4+ Intercalation of MXene. The specific method is as follows: the MXene slurry obtained in step (1) is placed in a tube furnace and rapidly heated to 500°C within 1 minute under vacuum, and then held at that temperature for 5 minutes to obtain rapidly annealed N-doped NH4. + Intercalation MXene.

[0038] (3) Finally, the active electrode was prepared using the same method as in Example 1, with an electrode surface loading of approximately 2 mg / cm³. -2 The electrochemical performance of the electrode was studied as the active electrode in a three-electrode system for a supercapacitor to verify the effects of N doping and NH4. + The synergistic effect of intercalation on improving the electrochemical performance of supercapacitors.

[0039] Figure 1 It is MAX powder, MXene powder etched by NH4F and hydrochloric acid in Example 2, NH4 + XRD characterization images of intercalated MXene and annealed MXene. It can be clearly seen from the figure that the interlayer spacing of intercalated MXene can reach 1.44 nm, while the interlayer spacing of MXene after rapid annealing is reduced to 1.37 nm.

[0040] Figure 2 The images show MXene powder (left) and N-doped NH4 obtained after rapid annealing for 5 min as described in Example 2. + SEM characterization image of intercalated MXene powder (right). The SEM image shows N-doped NH4. + Intercalated MXene exhibits a multi-layered structure.

[0041] Figure 3 It is via NH4 + FT-IR spectra of intercalated MXene materials and those subjected to rapid annealing at different times. The intercalated NH4+ can be clearly observed in the figures. + The characteristic peaks of NH4 after rapid annealing + Gradually removed. For samples with shorter annealing times, such as those annealed for 2 min and 5 min (Example 2), some NH4 will still remain after rapid annealing. + Residue.

[0042] Figure 4 N-doped NH4 was obtained by heating to 500℃ for 1 minute and then holding for 5 minutes. + Fine-grained peak separation results of XPSN1s intercalated MXene. Table 1 shows the binding energy positions of the corresponding peaks. The analysis results demonstrate the simultaneous presence of NH4+. + And N doping.

[0043] Table 1

[0044]

[0045] Figure 5 Example 2 is N-doped NH4 + The performance comparison chart shows that intercalated MXene and unmodified MXene (obtained in Comparative Example 1) are used as electrode materials for supercapacitors. The CV curves show that at 10 mV s... -1 At the scan rate, N-doped NH4 + The area enclosed by the CV curve of intercalated MXene is much larger than that of unmodified MXene. Meanwhile, at 2A g... -1 At current densities, N-doped NH4 + The charge-discharge time of intercalated MXene is much longer than that of unmodified MXene. This indicates that N-doped NH4 + Intercalated MXenes have superior specific capacity.

[0046] Example 3

[0047] (1) First, prepare NH4 + Intercalated MXene slurry. Method is the same as in Example 1.

[0048] (2) Next, prepare N-doped NH4 + Intercalation of MXene; the specific method is as follows: the MXene slurry obtained in step (1) is placed in a tube furnace and rapidly heated to 500°C within 1 minute under vacuum, and then held at that temperature for 2 minutes to obtain rapidly annealed N-doped NH4. + Intercalation MXene.

[0049] (3) Finally, the active electrode is prepared in the same way as in Example 1.

[0050] The prepared electrode was subjected to three-electrode electrochemical testing, and its performance at 2 A g was [not specified]. -1 The specific capacitance at the given current density is 375.0 Fg. -1 , at 20F g -1 The capacity retention rate at the current density is 73.6%.

[0051] Example 4

[0052] (1) First, prepare NH4 + Intercalated MXene slurry. Method is the same as in Example 1.

[0053] (2) Next, prepare N-doped NH4 + Intercalation of MXene; the specific method is as follows: the MXene slurry obtained in step (1) is placed in a tube furnace, and the temperature is rapidly increased to 500°C in a vacuum environment for 1 minute, and then held for 10 minutes to obtain rapidly annealed N-doped NH4.+ Intercalation MXene.

[0054] (3) Finally, the active electrode is prepared in the same way as in Example 1.

[0055] The prepared electrode was subjected to three-electrode electrochemical testing, and its performance at 2 A g was [not specified]. -1 The specific capacitance at the given current density is 442.2 Fg. -1 In 20A g -1 The capacity retention rate at the specified current density is 90.4%.

[0056] Figure 6 This is a comparison of the electrochemical performance of samples subjected to rapid annealing at three different holding times, partially retaining NH4 introduced into the interlayer. + Based on ions, surface N doping was achieved, simultaneously realizing surface functional group modification and interlayer structure control. N-doped NH4 was prepared by rapid annealing for 5 min. + When intercalated MXene is used as an electrode material for supercapacitors, its properties in 2Ag -1 It has 482.3 F g at a current density. -1 High specific capacity. As the current density increases from 2A g... -1 Increased to 20A g -1 The electrode still retains 91.3% of its capacity.

[0057] Example 5

[0058] (1) First, prepare NH4 + Intercalated MXene slurry. Method is the same as in Example 1.

[0059] (2) Next, prepare N-doped NH4 + Intercalation of MXene. The specific method is as follows: the MXene slurry obtained in step (1) is placed in a tube furnace and heated in a vacuum environment at 5°C for s. -1 The temperature was rapidly increased to 500℃, and then held at that temperature for 5 minutes to obtain rapidly annealed N-doped NH4. + Intercalation MXene.

[0060] (3) Finally, the active electrode is prepared in the same way as in Example 1.

[0061] Example 6

[0062] (1) First, prepare NH4 +Intercalation of MXene: Ammonia was added to the solution after centrifugation and washing in step 1 for intercalation treatment. The initial mass ratio of MAX phase to ammonia was controlled at 1:1. The mixture was stirred at room temperature for 6 hours to remove byproducts generated during the etching process. After intercalation, the supernatant was removed by centrifugation, and ammonia was added again for shaking to redisperse the precipitate. This process was repeated several times until the pH of the final solution was approximately 8. The centrifugation speed was controlled at 8000 rpm and the centrifugation time was 5 minutes.

[0063] (2) Next, prepare N-doped NH4 + Intercalation MXene. The method is the same as in Example 1.

[0064] (3) Finally, the active electrode is prepared in the same way as in Example 1.

[0065] Example 7

[0066] (1) First, prepare N-doped NH4 + Intercalation of MXene: Ammonia was added to the solution after centrifugation and washing in step 1 for intercalation treatment. The initial mass ratio of MAX phase to ammonia was controlled at 1:6. The mixture was stirred at room temperature for 6 hours to remove byproducts generated during the etching process. After intercalation, the supernatant was removed by centrifugation, and ammonia was added again for shaking to redisperse the precipitate. This process was repeated several times until the pH of the final solution was approximately 8. The centrifugation speed was controlled at 8000 rpm and the centrifugation time was 5 minutes.

[0067] (2) Next, prepare N-doped NH4 + Intercalation MXene. The method is the same as in Example 1.

[0068] (3) Finally, the active electrode is prepared in the same way as in Example 1.

[0069] Comparative Example 1

[0070] MAX phase etching: 40 mL of hydrofluoric acid was added to a polytetrafluoroethylene beaker, and 2 g of MAX phase powder was weighed and slowly added to the hydrofluoric acid in 5 batches. The mixture was stirred at 40 °C for 48 h to etch the MAX phase. After etching, the etching solution was centrifuged at high speed to remove the supernatant acid layer. Ultrapure water was then added for redispersibility, followed by centrifugation and dilution, repeated 6 times until the pH of the solution reached 6. Specifically, the high-speed centrifugation cleaning method was as follows: the centrifugation speed was controlled at 8000 rpm for 10 min. Finally, MXene powder was obtained by freeze-drying.

[0071] Comparative Example 2

[0072] (1) First, the MAX phase is etched. The method is the same as in Example 1.

[0073] (2) Next, prepare N-doped NH4 + Intercalation of MXene: The specific method is as follows: n-Butylamine is added to the solution after centrifugation and washing in step 1 for intercalation treatment. The initial mass ratio of MAX phase to n-butylamine is controlled at 1:3. The mixture is stirred at room temperature for 6 hours, while removing byproducts generated during the etching process. After intercalation, the supernatant is removed by centrifugation, and then n-butylamine is added again and shaken to redisperse the precipitate. This process is repeated several times until the pH of the final solution is approximately 8. The centrifugation speed is controlled at 8000 rpm and the centrifugation time is 5 minutes. Finally, MXene powder is obtained by freeze-drying.

[0074] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An N-doped NH4 + The method for preparing intercalated MXene materials is characterized by: The preparation method steps are as follows: (1) MAX phase etching: Ti3AlC2 powder is etched with HF acid generated by the in-situ reaction of ammonium fluoride and concentrated hydrochloric acid. The etched reactants are centrifuged at high speed to remove the supernatant after centrifugation. Then, ultrapure water is added and shaken to redisperse the centrifuged precipitate. Repeat the centrifugation-redispersion process to obtain a dispersion of the etched product, multilayer MXene. The dosage of NH4F is 0.015~0.08 g / mL. -1 Concentrated hydrochloric acid; the mass ratio of MAX phase powder to NH4F is 1:1.6, and the MAX phase powder needs to be added to the etching solution in 5 to 6 batches; (2) NH4 + Intercalation: Ammonia was added to the multilayer MXene dispersion in step (1) for intercalation. After intercalation, the supernatant was removed by centrifugation, and the centrifuged precipitate was washed with ammonia to obtain NH4. + Intercalated MXene slurry; The mass ratio of MXene powder to ammonia water is 1:1~6, and the mixture is stirred at room temperature for 3~6 h to carry out intercalation treatment. (3) Preparation of N-doped multilayer MXene: The NH4 in step (2) is prepared by... + The intercalated MXene slurry was placed in a tube furnace, heated under vacuum and then held at that temperature. The furnace was then cooled using water circulation to obtain rapidly annealed N-doped NH4. + Intercalation MXene.

2. The N-doped NH4 according to claim 1 + The method for preparing intercalated MXene materials is characterized by: Step (1) The mass fraction of concentrated hydrochloric acid is 37%, and the etching conditions are stirring at 40°C for 18~60 h.

3. The N-doped NH4 according to claim 1 + The method for preparing intercalated MXenec materials is characterized by: Step (1) High-speed centrifugation cleaning method: control the rotation speed to 3000~10000 rpm, centrifugation time to 5~20 min; repeat centrifugation-redisperse until the pH value of the supernatant is 6.

4. The N-doped NH4 according to claim 1 + The method for preparing intercalated MXene materials is characterized by: In step (2), the centrifugation speed is controlled at 4000~10000 rpm. After centrifugation, the supernatant is removed, and ammonia is added and shaken to redisperse the centrifuged precipitate. Centrifugation is repeated 3~6 times.

5. The N-doped NH4 according to claim 1 + The method for preparing intercalated MXene materials is characterized by: The annealing conditions in step (3) are: 1~15 °C s in a tube furnace. -1 The material is heated to 400~700 ℃ at a certain heating rate, and then held at that temperature for 2~10 min after the heating is completed.

6. The N-doped NH4 according to claim 1 + The method for preparing intercalated MXene materials is characterized by: In step (3), the circulating water cooling enables the tubular furnace to operate at 15~20 ℃ min. -1 The temperature was lowered, and after 20-30 minutes, the tubular furnace cooled to room temperature.

7. An N-doped NH4 prepared by the method according to any one of claims 1-6 + Intercalated MXene material.

8. An N-doped NH4 prepared by the method according to any one of claims 1-6 + The application of intercalated MXene materials is characterized by: The N-doped NH4 + Intercalated MXene materials are used as active materials in the fabrication of supercapacitor electrodes.

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