Controllable preparation method of disordered MXenes-based composite aerogel electrode for supercapacitor

Abstract

The invention discloses a controllable preparation method of a disordered MXenes-based composite aerogel electrode for a supercapacitor, and relates to the technical field of new materials. According to the method for improving the electrochemical performance and the mechanical performance of the MXene-based composite aerogel electrode supercapacitor through the adjustable disordered porous ion transmission channel, the electrochemical performance of the MXene-based composite aerogel electrode is remarkably improved by accurately adjusting and controlling the pore structure and the pore size; the method is of great significance to development of supercapacitors and other electrochemical energy storage devices, development of the supercapacitor technology is promoted, new possibility is provided for future energy storage and conversion devices, disordered treatment of MXenes materials is achieved through specific chemical or physical means, and the method is suitable for large-scale popularization and application. And the disordered MXenes-based composite aerogel electrode can provide more active sites and enhance the electrochemical activity of the electrode material, so that the specific capacitance and the energy density of the supercapacitor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and in particular to a controllable preparation method of disordered MXenes-based composite aerogel electrodes for supercapacitors. Background Art

[0002] As an efficient energy storage device, supercapacitors have attracted extensive attention due to their advantages such as fast charging and discharging capabilities, long cycle life and high power density. In the research of supercapacitors, MXene-based composite aerogel electrodes have become a hot topic due to their unique structure and performance. MXene is a type of transition metal carbide, nitride or carbonitride with a two-dimensional layered structure. They have high conductivity, large specific surface area and abundant surface functional groups. These characteristics make MXene exhibit excellent electrochemical performance in supercapacitors.

[0003] Although MXene materials show great application potential in fields such as supercapacitors due to their unique properties, they also have some disadvantages and challenges. First, the etching methods commonly used in the preparation of MXene, such as HF and HCl / LiF, are toxic and corrosive, which not only poses a threat to the environment and operators, but also limits its large-scale production application. Secondly, although more than 100 MXene materials have been predicted, only 30 have been successfully synthesized, which limits the diversity and application range of MXene materials. In addition, the surface chemical state of MXene materials has a significant impact on their electrochemical properties, but there is currently a lack of effective characterization methods to distinguish different functional groups. MXene materials also show poor stability and are easily oxidized due to structural defects, active transition metals and end groups, which limits their development in certain application fields. Finally, although MXene materials have excellent mechanical properties, structural defects such as pores and sheet wrinkles may reduce their mechanical properties, and the self-stacking of sheets caused by van der Waals forces is the main factor affecting their electrochemical properties. Therefore, in order to fully realize the potential of MXene materials, it is necessary to further study and optimize its preparation process and structural design, improve quality and yield, and deeply study the relationship between its structure and performance. MXene can be processed into a three-dimensional porous framework structure through different synthesis methods, such as gel assembly, freeze drying, sacrificial template method, etc., to improve the accessibility of electrolyte ions and enhance its electrochemical performance.

[0004] In the study of electrode materials for supercapacitors, MXene-based composite aerogel electrodes have attracted much attention due to their rich porosity and a large number of active sites, and the optimization of pore structure is the key to improving electrode performance. At present, most studies believe that MXene aerogel materials with ordered structures can significantly improve the capacitance performance of supercapacitors. This ordered three-dimensional porous structure not only provides greater porosity and higher specific surface area, but also shortens the ion transmission distance, thereby enhancing the electrochemical performance of the material. In addition, the ordered structure can effectively avoid the self-stacking phenomenon of MXene nanosheets, maintain the high electron transmission capacity of the material, and reduce the attenuation of electrochemical performance. However, recent studies have shown that porous carbon with disordered structure can adsorb ions to a greater extent and increase capacitance. In addition, some studies have shown through molecular dynamics simulation that in the disordered nanoporous carbon electrode model, the adsorption mode of ions varies greatly due to different local structures, and the local charge storage efficiency on the electrode surface is strongly related to the local confinement degree (DoC) of nearby adsorbed ions. The disordered structure may promote the transfer of charge in the electrode material, especially in aerogels with high conductivity. This enhanced charge transfer can improve the electrochemical activity of the electrode, thereby increasing the capacitance.

[0005] In order to solve this problem, different assembly methods have been explored to construct three-dimensional porous structures and regulate the pore size distribution and pore size to optimize the mechanical properties, electrical properties and photothermal conversion performance of MXene porous materials. However, most of the current research remains at the macroscopic level, and it is difficult to design the structure and properties of aerogels by regulating the preparation parameters to achieve controllable synthesis of aerogel materials. Although changing the strength of hydrogen bonds can inhibit the aggregation of aerogel skeleton structures, this process requires precise control and has high requirements for experimental conditions. Problems such as the high brittleness, limited transparency and hygroscopicity of aerogels have not yet been well resolved;

[0006] Therefore, a new solution to the above problems needs to be proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a controllable preparation method of disordered MXenes-based composite aerogel electrodes for supercapacitors. This method is used for supercapacitors. This method can be understood as a method for improving the electrochemical properties and mechanical properties of MXene-based composite aerogel electrodes supercapacitors by using controllable disordered porous ion transport channels. In general, the electrochemical properties of MXene-based composite aerogel electrodes can be significantly improved by precisely controlling the pore structure and size, which is of great significance for the development of supercapacitors and other electrochemical energy storage devices. These studies not only promote the development of supercapacitor technology, but also provide new possibilities for future energy storage and conversion devices to solve the technical problems raised in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a method for controllably preparing a disordered MXenes-based composite aerogel electrode for a supercapacitor, comprising at least the following steps:

[0009] S1: Preparation of MXene materials;

[0010] S2: Preparation of polymer solution: weigh 1 gram of polymer powder, heat in a water bath at 85°C with magnetic stirring for 0.5h-3h, and prepare 10mg ml -1 -50mg ml -1 A polymer dispersion;

[0011] S3: Preparation of MPA, where M represents MXene, P represents polymer, and A represents aerogel;

[0012] S4: Performance optimization of MPA;

[0013] S5: Using MPA as an electrode, a supercapacitor is prepared.

[0014] Furthermore, the S1 at least comprises the following steps:

[0015] Ti3AlC2 with 200-600 mesh was selected as the MAX phase precursor, which is the preparation of Ti3C2T x Basic materials;

[0016] First, Ti3AlC2 powder is slowly mixed with 6M-9M hydrochloric acid or 30%wt-70%wt hydrofluoric acid solution in an ice bath to perform wet chemical etching to selectively remove the Al layer and generate MXene;

[0017] Perform water bath heating etching for 24-60 hours;

[0018] After etching, the reaction solution is rinsed several times with deionized water to remove residual etchant and byproducts;

[0019] Then, MXene was separated by centrifugation, the supernatant was poured out, deionized water was added, and Ti3C2T was manually shaken. x dispersion, and repeat this process until the pH of the supernatant is neutral;

[0020] The supernatant was ultrasonicated to obtain layered Ti3C2T x Nanosheets; Finally, the aqueous dispersion was freeze-dried to obtain Ti3C2T x powder.

[0021] Furthermore, the preparation of MPA in S3 comprises at least the following steps:

[0022] Ti3C2T was prepared in a mass ratio of 1:0.1-1:5. x and a polymer dispersion to obtain a mixed solution;

[0023] The mixed solution was stirred at low speed for 0.5h-3h;

[0024] Then, the mixed solution is directionally frozen by immersing the copper plate with liquid nitrogen to obtain ice crystals that grow in an orderly manner according to the temperature gradient, i.e., a frozen sample;

[0025] Next, the frozen samples are stored in an ultra-low temperature freezer at -40°C or below;

[0026] Finally, it is transferred to a freeze dryer for drying for more than 12 hours to remove moisture and form a porous structure.

[0027] Furthermore, the S4 at least includes the following steps:

[0028] After completing the freeze-drying step in S3, a preliminary composite aerogel sample combining MXene and polymer was obtained;

[0029] To further enhance its structural stability and improve its electrochemical performance, the composite aerogel sample was next transferred to a pre-programmed tube furnace;

[0030] The interior of the tube furnace is filled with an inert argon atmosphere, which prevents oxidation of the sample during high-temperature treatment, thereby maintaining the original properties of MXene;

[0031] Next, set the heating program so that the sample starts from room temperature and gradually heats to 300℃-800℃ at a uniform heating rate of 2℃-10℃ per minute. This slow heating process helps the sample gradually adapt to the temperature change and avoids the destruction of the material structure due to too fast temperature change.

[0032] When a certain temperature is reached, the temperature is maintained for 1-6 hours to ensure that the polymer in the aerogel is completely decomposed and removed from the MXene layers, while promoting the restacking and densification of the MXene layers to form a more stable three-dimensional network structure;

[0033] After the insulation is completed, turn off the heating system and let the temperature in the furnace drop naturally to room temperature. This cooling process also needs to be carried out slowly to avoid thermal stress caused by excessive temperature difference, which may damage the structure of the aerogel.

[0034] After the temperature completely drops to room temperature, the aerogel sample is taken out of the tube furnace to obtain MXene aerogel.

[0035] Furthermore, the S5 at least includes the following steps:

[0036] Select 1M-3M H2SO4 as the electrolyte;

[0037] MPA composite aerogel as electrode;

[0038] Assembled into a symmetrical supercapacitor.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] Although existing supercapacitor electrode materials have made certain progress in the field of energy storage, they still have some limitations. For example, many traditional electrode materials such as activated carbon and carbon nanotubes, although they have a high specific surface area, have relatively low electrochemical activity, resulting in low energy density. At the same time, these materials are easy to stack during the charging and discharging process, which further reduces their electrochemical performance. In addition, some high-performance electrode materials such as metal oxides and conductive polymers, although they can provide higher energy density, are often accompanied by poor cycle stability and mechanical properties, which limits their long-term application. Therefore, the development of new electrode materials with high energy density, excellent cycle stability and good mechanical properties is a key issue to be urgently solved in the field of supercapacitors. The invention of titanium carbide and polymer-derived carbon composite aerogel electrodes prepared by freeze-drying technology is precisely to overcome the limitations of these prior arts and provide a new high-performance electrode material solution. Compared with traditional electrode materials, the composite aerogel electrode of the present invention has the following significant beneficial effects:

[0041] First, due to the application of freeze-drying technology, the prepared aerogel electrode forms a unique porous structure, which not only enhances the mechanical stability of the electrode, but also improves its durability in long-term cyclic use. This improvement in mechanical stability means that the electrode can maintain structural integrity during repeated charge and discharge, thereby significantly extending the service life of the supercapacitor.

[0042] Secondly, the method of the present invention provides a technical solution for regulating the order of the porous structure of the aerogel electrode, and a disordered porous MXene / carbon aerogel is obtained by adjusting the annealing temperature, time, polymer addition ratio, and precursor preparation method. The high specific surface area and good conductivity of the composite aerogel electrode provide more active sites for ions in the electrolyte, which promotes rapid charge transfer, thereby achieving high capacitance. In addition, the doping of the polymer helps to maintain the separation of the titanium carbide layer, prevents the stacking phenomenon during the charge and discharge process, and further improves the electrochemical activity of the electrode. Furthermore, the disordered porous structure optimizes the ion transmission path and reduces the resistance of ion transmission, which directly improves the power density and charge and discharge rate of the supercapacitor, so that the electrode material of the present invention performs well in fast charge and discharge applications. In addition, the aerogel electrode prepared by freeze-drying technology is more chemically stable, can work in a wider electrochemical window, and reduces the performance attenuation caused by chemical decomposition, which provides a guarantee for the safety and reliability of the supercapacitor.

[0043] Finally, the environmentally friendly characteristics of freeze-drying technology make the preparation process of the present invention more environmentally friendly, without the use of harmful organic solvents, reducing the impact on the environment, and meeting the requirements of green chemistry and sustainable development. At the same time, due to its excellent comprehensive performance, the composite aerogel electrode of the present invention has a wide range of application potential, not only for supercapacitors, but also for other energy storage and conversion devices, such as batteries, sensors and catalysis, providing new ideas for the development of high-performance energy storage materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0045] Figure 1 The technical roadmap for preparing the MXene / polymer composite aerogel electrode of the present invention;

[0046] Figure 2 This is the SEM image of the internal 3D network interconnected structure of the MXene and PVA composite aerogels of the present invention in different proportions. DETAILED DESCRIPTION

[0047] MXene materials have shown great potential in the field of supercapacitor electrode materials due to their unique two-dimensional structure and rich surface functional groups. However, MXene sheets are prone to self-stacking due to van der Waals forces during preparation and application, and this phenomenon has a significant impact on electrochemical performance. Stacking will lead to a decrease in the specific surface area of ​​MXene, reduce the contact area between the electrolyte and the active material, thereby reducing the number of electrochemically active sites, affecting the transmission and diffusion of ions, and ultimately leading to a decrease in capacitance and power density. In order to solve this problem, the present invention adopts a variety of strategies, such as preventing the self-stacking of MXene sheets by constructing a three-dimensional porous structure and introducing other materials to form a composite material to improve its electrochemical performance in supercapacitors. The core is to achieve disordered treatment of MXenes materials through specific chemical or physical means, thereby increasing the specific surface area of ​​the material and improving its ion diffusion performance. The disordered MXenes-based composite aerogel electrode can provide more active sites, enhance the electrochemical activity of the electrode material, and thus improve the specific capacitance and energy density of the supercapacitor.

[0048] A method for controllably preparing a disordered MXenes-based composite aerogel electrode for a supercapacitor comprises at least the following steps:

[0049] S1: Preparation of MXene materials;

[0050] S2: Preparation of polymer solution: weigh 1 gram of polymer powder, heat in a water bath at 85°C with magnetic stirring for 0.5h-3h, and prepare 10mg ml -1 -50mg ml -1 A polymer dispersion;

[0051] S3: Preparation of MPA, M stands for MXene, P stands for polymer, and A stands for aerogel;

[0052] S4: Performance optimization of MPA;

[0053] S5: Using MPA as an electrode, a supercapacitor is prepared.

[0054] S1 includes at least the following steps:

[0055] Ti3AlC2 with 200-600 mesh was selected as the MAX phase precursor, which is the preparation of Ti3C2T x Basic materials;

[0056] First, Ti3AlC2 powder is slowly mixed with 6M-9M hydrochloric acid or 30%wt-70%wt hydrofluoric acid solution in an ice bath to perform wet chemical etching to selectively remove the Al layer and generate MXene;

[0057] Perform water bath heating etching for 24-60 hours;

[0058] After etching, the reaction solution is rinsed several times with deionized water to remove residual etchant and byproducts;

[0059] Then, MXene was separated by centrifugation, the supernatant was poured out, deionized water was added, and Ti3C2T was manually shaken. x dispersion, and repeat this process until the pH of the supernatant is neutral;

[0060] The supernatant was ultrasonicated to obtain layered Ti3C2T x Nanosheets; Finally, the aqueous dispersion was freeze-dried to obtain Ti3C2T x powder.

[0061] The preparation of MPA in S3 comprises at least the following steps:

[0062] Ti3C2T was prepared in a mass ratio of 1:0.1-1:5. x and a polymer dispersion to obtain a mixed solution;

[0063] The mixed solution was stirred at low speed for 0.5h-3h;

[0064] Then, the mixed solution is directionally frozen by immersing the copper plate with liquid nitrogen to obtain ice crystals that grow in an orderly manner according to the temperature gradient, i.e., a frozen sample;

[0065] Next, the frozen samples are stored in an ultra-low temperature freezer at -40°C or below;

[0066] Finally, it is transferred to a freeze dryer for drying for more than 12 hours to remove moisture and form a porous structure.

[0067] S4 at least includes the following steps:

[0068] After completing the freeze-drying step in S3, a preliminary composite aerogel sample combining MXene and polymer was obtained;

[0069] To further enhance its structural stability and improve its electrochemical performance, the composite aerogel sample was next transferred to a pre-programmed tube furnace;

[0070] The interior of the tube furnace is filled with an inert argon atmosphere, which prevents oxidation of the sample during high-temperature treatment, thereby maintaining the original properties of MXene;

[0071] Next, set the heating program so that the sample starts from room temperature and gradually heats to 300℃-800℃ at a uniform heating rate of 2℃-10℃ per minute. This slow heating process helps the sample gradually adapt to the temperature change and avoids the destruction of the material structure due to too fast temperature change.

[0072] When a certain temperature is reached, the temperature is maintained for 1-6 hours to ensure that the polymer in the aerogel is completely decomposed and removed from the MXene layers, while promoting the restacking and densification of the MXene layers to form a more stable three-dimensional network structure;

[0073] After the insulation is completed, turn off the heating system and let the temperature in the furnace drop naturally to room temperature. This cooling process also needs to be carried out slowly to avoid thermal stress caused by excessive temperature difference, which may damage the structure of the aerogel.

[0074] After the temperature completely drops to room temperature, the aerogel sample is taken out of the tube furnace to obtain MXene aerogel.

[0075] S5 at least includes the following steps:

[0076] Select 1M-3M H2SO4 as the electrolyte;

[0077] MPA composite aerogel as electrode;

[0078] Assembled into a symmetrical supercapacitor.

[0079] Through the gradual implementation of the above steps, the technical route is as follows Figure 1 As shown, the stacked layers of MXene materials produced by van der Waals forces are stretched apart by orderly grown ice crystals, effectively improving the electrochemical performance of the composite aerogel.

[0080] See also Figure 2 It can be seen that the internal 3D network structure of MXene and PVA in different proportions of composite aerogels is interconnected.

[0081] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0082] Embodiment 1:

[0083] Step 1: Preparation of MXene materials. Use 400 mesh Ti3AlC2 as the MAX phase precursor, which is the preparation of Ti3C2T xFirst, Ti3AlC2 powder was slowly added to 9M H2SO4 solution in an ice bath for 5 minutes to avoid overheating, and then stirred at 35°C for 48 hours; after etching, the reaction solution was rinsed with deionized water several times to remove residual etchant and by-products; then MXene was separated by centrifugation, the supernatant was poured out, and deionized water was added and Ti3C2T was manually shaken. x The dispersion was prepared by ultrasonic treatment to obtain the layered Ti3C2T x Nanosheets; Finally, the aqueous dispersion was freeze-dried to obtain Ti3C2T x powder.

[0084] Step 2: Preparation of PVA solution. Weigh 1 gram of polyvinyl alcohol powder (PVA), heat it in a water bath at 85°C with magnetic stirring for 2 h, and prepare 10 mg ml -1 A clear dispersion of PVA.

[0085] Step 3: Preparation of MPA composite aerogel. x The mass ratio of PVA to Ti3C2T is 1:0.1. x and PVA mixed dispersion; the mixed solution was heated at 480 rmin -1 The mixture was stirred for 2 hours under the conditions of 40 °C; then the mixed solution was directionally frozen in a copper pan immersed in liquid nitrogen to obtain ice crystals that grew orderly according to the temperature gradient; the frozen sample was then stored in an ultra-low temperature freezer at -80 °C for 24 hours; finally, it was transferred to a freeze dryer for 48 hours to remove moisture and form a porous structure.

[0086] Step 4: Performance optimization of MPA composite aerogel. After completing the freeze-drying step, we obtained preliminary MXene / PVA aerogel. In order to further enhance its structural stability and improve its electrochemical performance, the aerogel samples were then transferred to a pre-programmed tubular furnace. The interior of the tubular furnace is filled with an inert argon atmosphere, which prevents the sample from oxidizing during high-temperature treatment, thereby maintaining the original properties of the MXene. Next, the heating program was set so that the sample was gradually heated from room temperature to 400°C at a uniform heating rate of 5°C per minute. This slow heating process helps the sample gradually adapt to the temperature change and avoids the destruction of the material structure due to too rapid temperature change. When the temperature reaches 400°C, this temperature is maintained for 2 hours to ensure that the PVA in the aerogel is completely decomposed and removed from the MXene layer, while promoting the restacking and densification of the MXene layer, thereby forming a more stable three-dimensional network structure. After the insulation is completed, the heating system is turned off and the temperature in the furnace is allowed to drop naturally to room temperature. This cooling process also needs to be carried out slowly to avoid thermal stress caused by excessive temperature differences, which may damage the structure of the aerogel. After the temperature completely drops to room temperature, we take the aerogel sample out of the tube furnace. After this heat treatment process, we can get carbonized Ti3C2T x MPA composite aerogel with a mass ratio of MPA to PVA of 1:0.1.

[0087] Step 5: Preparation of MPA composite aerogel supercapacitor: Select 1M H2SO4 as the electrolyte and MPA composite aerogel as the electrode to assemble into a symmetrical supercapacitor.

[0088] Embodiment 2:

[0089] Step 1: Preparation of MXene materials. Use 400 mesh Ti3AlC2 as the MAX phase precursor, which is the preparation of Ti3C2T x First, Ti3AlC2 powder was slowly added to 9M H2SO4 solution in an ice bath for 5 minutes to avoid overheating, and then stirred at 35°C for 48 hours; after etching, the reaction solution was rinsed with deionized water several times to remove residual etchant and by-products; then MXene was separated by centrifugation, the supernatant was poured out, and deionized water was added and Ti3C2T was manually shaken. x The dispersion was prepared by ultrasonic treatment to obtain the layered Ti3C2T x Nanosheets; Finally, the aqueous dispersion was freeze-dried to obtain Ti3C2T x powder.

[0090] Step 2: Preparation of PVA solution. Weigh 1 gram of polyvinyl alcohol powder (PVA), heat it in a water bath at 85°C with magnetic stirring for 2 h, and prepare 10 mg ml -1 A clear dispersion of PVA.

[0091] Step 3: Preparation of MPA composite aerogel. x Ti3C2T was prepared with a mass ratio of 1:0.5 to PVA. x and PVA mixed dispersion; the mixed solution was heated at 480 rmin -1 The mixture was stirred for 2 hours under the conditions of 40 °C; then the mixed solution was directionally frozen in a copper pan immersed in liquid nitrogen to obtain ice crystals that grew orderly according to the temperature gradient; the frozen sample was then stored in an ultra-low temperature freezer at -80 °C for 24 hours; finally, it was transferred to a freeze dryer for 48 hours to remove moisture and form a porous structure.

[0092] Step 4: Performance optimization of MPA composite aerogel. After completing the freeze-drying step, we obtained preliminary MXene / PVA aerogel. In order to further enhance its structural stability and improve its electrochemical performance, the aerogel samples were then transferred to a pre-programmed tubular furnace. The interior of the tubular furnace is filled with an inert argon atmosphere, which prevents the sample from oxidizing during high-temperature treatment, thereby maintaining the original properties of the MXene. Next, the heating program was set so that the sample was gradually heated from room temperature to 500°C at a uniform heating rate of 5°C per minute. This slow heating process helps the sample gradually adapt to the temperature change and avoids the destruction of the material structure due to too rapid temperature changes. When the temperature reaches 500°C, this temperature is maintained for 2 hours to ensure that the PVA in the aerogel is completely decomposed and removed from the MXene layers, while promoting the restacking and densification of the MXene layers to form a more stable three-dimensional network structure. After the insulation is completed, the heating system is turned off and the temperature in the furnace is allowed to drop naturally to room temperature. This cooling process also needs to be carried out slowly to avoid thermal stress caused by excessive temperature differences, which may damage the structure of the aerogel. After the temperature completely drops to room temperature, we take the aerogel sample out of the tube furnace. After this heat treatment process, we can get carbonized Ti3C2T x MPA composite aerogel with a mass ratio of MPA to PVA of 1:0.5.

[0093] Step 5: Preparation of MPA composite aerogel supercapacitor: Select 1M H2SO4 as the electrolyte and MPA composite aerogel as the electrode to assemble into a symmetrical supercapacitor.

[0094] Embodiment three:

[0095] Step 1: Preparation of MXene materials. Use 400 mesh Ti3AlC2 as the MAX phase precursor, which is the preparation of Ti3C2T x First, Ti3AlC2 powder was slowly added to 9M H2SO4 solution in an ice bath for 5 minutes to avoid overheating, and then stirred at 35°C for 48 hours; after etching, the reaction solution was rinsed with deionized water several times to remove residual etchant and by-products; then MXene was separated by centrifugation, the supernatant was poured out, and deionized water was added and Ti3C2T was manually shaken. x The dispersion was prepared by ultrasonic treatment to obtain the layered Ti3C2T x Nanosheets; Finally, the aqueous dispersion was freeze-dried to obtain Ti3C2T x powder.

[0096] Step 2: Preparation of PVA solution. Weigh 1 g of polyvinyl alcohol powder (PVA), heat in a water bath at 85°C with magnetic stirring for 2 h, and prepare 20 mg ml -1 A clear dispersion of PVA.

[0097] Step 3: Preparation of MPA composite aerogel. x Ti3C2T was prepared with a mass ratio of 1:1 with PVA. x and PVA mixed dispersion; the mixed solution was heated at 480 rmin -1 The mixture was stirred for 2 hours under the conditions of 40 °C; then the mixed solution was directionally frozen in a copper pan immersed in liquid nitrogen to obtain ice crystals that grew orderly according to the temperature gradient; the frozen sample was then stored in an ultra-low temperature freezer at -80 °C for 24 hours; finally, it was transferred to a freeze dryer for 48 hours to remove moisture and form a porous structure.

[0098] Step 4: Performance optimization of MPA composite aerogel. After completing the freeze-drying step, we obtained preliminary MXene / PVA aerogel. In order to further enhance its structural stability and improve its electrochemical performance, the aerogel samples were then transferred to a pre-programmed tubular furnace. The interior of the tubular furnace is filled with an inert argon atmosphere, which prevents the sample from oxidizing during high-temperature treatment, thereby maintaining the original properties of the MXene. Next, the heating program was set so that the sample was gradually heated from room temperature to 300°C at a uniform heating rate of 5°C per minute. This slow heating process helps the sample gradually adapt to the temperature change and avoids the destruction of the material structure due to too rapid temperature change. When the temperature reaches 300°C, this temperature is maintained for 2 hours to ensure that the PVA in the aerogel is completely decomposed and removed from the MXene layer, while promoting the restacking and densification of the MXene layer, thereby forming a more stable three-dimensional network structure. After the insulation is completed, the heating system is turned off and the temperature in the furnace is allowed to drop naturally to room temperature. This cooling process also needs to be carried out slowly to avoid thermal stress caused by excessive temperature differences, which may damage the structure of the aerogel. After the temperature completely drops to room temperature, we take the aerogel sample out of the tube furnace. After this heat treatment process, we can get carbonized Ti3C2T x MPA composite aerogel with a mass ratio of MPA to PVA of 1:1.

[0099] Step 5: Preparation of MPA composite aerogel supercapacitor: Select 1M H2SO4 as the electrolyte and MPA composite aerogel as the electrode to assemble into a symmetrical supercapacitor.

[0100] Through the gradual implementation of the above steps, the technical route is as follows Figure 1 shown.

[0101] In addition, the above only uses PVA material as an example, but the polymer in the present invention is not limited to PVA, but also includes other polymers with similar properties (such as polylactic acid, polycaprolactone, starch, cellulose, hemicellulose, lignin, conductive polymers, etc.).

[0102] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A controllable preparation method of disordered MXenes-based composite aerogel electrodes for supercapacitors, characterized in that: At least the following steps are included: S1: Preparation of MXene materials; S2: Preparation of polymer solution: weigh 1 gram of polymer powder, heat in a water bath at 85°C with magnetic stirring for 0.5h-3h, and prepare 10mg ml -1 -50mg ml -1 A polymer dispersion; S3: Preparation of MPA, where M represents MXene, P represents polymer, and A represents aerogel; S4: Performance optimization of MPA; S5: Using MPA as an electrode, a supercapacitor is prepared.

2. The method for controllably preparing a disordered MXenes-based composite aerogel electrode for a supercapacitor according to claim 1, characterized in that: The S1 at least comprises the following steps: Ti3AlC2 with 200-600 mesh was selected as the MAX phase precursor, which is the preparation of Ti3C2T x Basic materials; First, Ti3AlC2 powder is slowly mixed with 6M-9M hydrochloric acid or 30%wt-70%wt hydrofluoric acid solution in an ice bath to perform wet chemical etching to selectively remove the Al layer and generate MXene; Perform water bath heating etching for 24-60 hours; After etching, the reaction solution is rinsed several times with deionized water to remove residual etchant and byproducts; Then, MXene was separated by centrifugation, the supernatant was poured out, deionized water was added, and Ti3C2T was manually shaken. x dispersion, and repeat this process until the pH of the supernatant is neutral; The supernatant was ultrasonicated to obtain layered Ti3C2T x Nanosheets; Finally, the aqueous dispersion was freeze-dried to obtain Ti3C2T x powder.

3. The controllable preparation method of the disordered MXenes-based composite aerogel electrode for supercapacitor according to claim 2, characterized in that: The preparation of the MPA in S3 at least comprises the following steps: Ti3C2T was prepared in a mass ratio of 1:0.1-1:

5. x and a polymer dispersion to obtain a mixed solution; The mixed solution was stirred at low speed for 0.5h-3h; Then, the mixed solution is directionally frozen by immersing the copper plate with liquid nitrogen to obtain ice crystals that grow in an orderly manner according to the temperature gradient, i.e., a frozen sample; Next, the frozen samples are stored in an ultra-low temperature freezer at -40°C or below; Finally, it is transferred to a freeze dryer for drying for more than 12 hours to remove moisture and form a porous structure.

4. The controllable preparation method of the disordered MXenes-based composite aerogel electrode for supercapacitor according to claim 3, characterized in that: The S4 at least comprises the following steps: After completing the freeze-drying step in S3, a preliminary composite aerogel sample combining MXene and polymer was obtained; To further enhance its structural stability and improve its electrochemical performance, the composite aerogel sample was next transferred to a pre-programmed tube furnace; The interior of the tube furnace is filled with an inert argon atmosphere, which prevents oxidation of the sample during high-temperature treatment, thereby maintaining the original properties of MXene; Next, set the heating program so that the sample starts from room temperature and gradually heats to 300℃-800℃ at a uniform heating rate of 2℃-10℃ per minute. This slow heating process helps the sample gradually adapt to the temperature change and avoids the destruction of the material structure due to too fast temperature change. When a certain temperature is reached, the temperature is maintained for 1-6 hours to ensure that the polymer in the aerogel is completely decomposed and removed from the MXene layers, while promoting the restacking and densification of the MXene layers to form a more stable three-dimensional network structure; After the insulation is completed, turn off the heating system and let the temperature in the furnace drop naturally to room temperature. This cooling process also needs to be carried out slowly to avoid thermal stress caused by excessive temperature difference, which may damage the structure of the aerogel. After the temperature completely drops to room temperature, the aerogel sample is taken out of the tube furnace to obtain MXene aerogel.

5. The method for controllably preparing a disordered MXenes-based composite aerogel electrode for a supercapacitor according to claim 4, characterized in that: The S5 at least comprises the following steps: Select 1M-3M H2SO4 as the electrolyte; MPA composite aerogel as electrode; Assembled into a symmetrical supercapacitor.

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