Vanadium-based metal organic framework derivative modified MXene-based nanocomposite and preparation method thereof
By modifying MIL-88B(V) derivatives on MXene nanosheets and building a three-dimensional conductive network, the problem of MXene nanosheets was solved, and efficient zinc ion capacitor electrode performance was achieved.
Patent Information
- Application Number
- CN202510513569.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2025-08-15
AI Technical Summary
In existing zinc ion capacitors, the re-stacking problems caused by the van der Waals force and hydrogen bond between MXene nanosheets lead to a decrease in the reachable surface area, conductivity and active sites, making it difficult to meet the application needs of high zinc storage capacity.
The MXene nanosheets were modified by solvothermal method and converted into vanadium oxides by carbonization to construct a three-dimensional conductive network, inhibiting MXene self-stacking, providing additional active sites and ion diffusion channels.
The electrochemical performance of MXene matrix composite electrode is enhanced, the specific capacity and cycling stability are improved, and the efficient charging and discharge process of zinc ion capacitors is promoted.
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Figure CN120497053A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of nano-functional materials and electrochemical energy storage devices, and particularly relates to a vanadium-based metal-organic framework (MIL-88B(V)) derivative-modified MXene-based nano-composite material, a supercapacitor electrode and a preparation method thereof. Background Art
[0002] In the past few decades, the energy depletion and environmental pollution problems caused by the excessive consumption of non-renewable resources have prompted the scientific and industrial communities to focus on new energy technologies. Zinc-ion hybrid supercapacitors (ZnIon Capacitors for short) combine the high power characteristics of supercapacitors with the high energy characteristics of zinc-ion batteries, thus showing high energy density, ultra-long cycle life and excellent reliability, and showing great application potential in the field of large-scale energy storage. However, the carbon-based materials used in zinc-ion capacitors are difficult to match with the more active zinc negative electrode due to the limitations of their double-layer energy storage mechanism, resulting in an imbalance in the positive and negative electrode reaction kinetics, making it difficult to meet the application requirements of high zinc storage capacity. Therefore, the development of a high-capacity zinc-ion capacitor positive electrode material that matches the zinc negative electrode is a key issue that needs to be solved urgently.
[0003] MXene has been widely explored as a cathode material for zinc-ion capacitors due to its unique two-dimensional structure, controllable interlayer spacing, excellent specific capacitance, high conductivity, and good mechanical stability. Although MXene has unique advantages in the field of zinc storage, the unavoidable problem of van der Waals interactions between its nanosheets and the re-stacking caused by hydrogen bonding still leads to a significant reduction in its accessible surface area, conductivity, and active sites. As a result, the application of MXene in zinc-ion capacitors is severely limited by its relatively low theoretical capacity.
[0004] To address these issues, researchers have employed a variety of methods to suppress interlayer interactions within MXene, such as surface functionalization, organic cation intercalation, and heteroatom doping, to improve its electrochemical performance. Furthermore, heterogeneous interface engineering (composite modification) has proven to be an effective material modification strategy. Combining MXene with other materials (such as conductive polymers, carbon nanomaterials, and metal oxides) allows for the directed construction of three-dimensional open structures. This not only helps suppress the restacking and aggregation of MXene flakes, providing more active sites, but also forms continuous conduction channels, promoting rapid charge transfer.
[0005] Among many nanomaterials, metal-organic frameworks are porous materials with large specific surface areas and diverse structures. Their morphology, particles, and pore size can be controlled by the synthesis process, solvent type, and experimental parameters. The controllable properties of metal-organic frameworks enable them to design and create hierarchical structures that promote rapid ion diffusion according to needs, thereby accelerating the charge and discharge process. In addition, their derivatives (such as metal oxides, metal sulfides, metal phosphides, etc.) have open and stable structures and more uniform pore distribution, which are important factors in achieving electrochemical performance. Combining the conductivity of MXene with the redox activity of metal-organic frameworks, their synergistic effect can achieve an ideal balance between the two matrices. Among the many metal-organic framework materials, MIL-88B(V) and its derivatives have been evaluated as efficient positive electrode materials in the field of zinc ion energy storage. Under electrochemical oxidation, MIL-88B(V) derivatives can be converted in situ into amorphous V2O x , for the subsequent Zn 2+ The intercalation / deintercalation provides abundant active sites, which accelerates the Zn 2+ diffusion rate. Summary of the Invention
[0006] The present invention aims to provide a MIL-88B(V) derivative-modified MXene-based nanocomposite and its preparation method. First, using layered Ti3AlC2 ceramic powder as a precursor, the Al layer is etched away using a mixed etchant containing HCl / LiF ions to obtain a high-quality MXene nanomaterial. Then, using the MXene nanomaterial as a matrix, a mixed organic solution of vanadium chloride and terephthalic acid is used to prepare the MIL-88B(V) derivative-modified MXene-based nanocomposite via a solvothermal method. The composite is then fabricated into electrodes using an electrode preparation process for use in zinc ion hybrid supercapacitors. The resulting electrode material exhibits excellent electrochemical performance.
[0007] In order to achieve the above objectives, the present invention provides a MIL-88B(V) derivative-modified MXene-based nanocomposite material and a preparation method thereof, comprising the following steps:
[0008] 1) Ti3AlC2 was etched in liquid phase using an etchant to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution was sonicated at low temperature under an inert atmosphere such as argon or nitrogen, and the upper suspension was collected by centrifugation to obtain a concentration of 1.0 to 8.0 mg mL -1 The single / few-layer MXene nanosheet sol solution is freeze-dried at -65°C to -55°C for 48 to 72 hours, and the obtained single / few-layer MXene powder is defined as powder A;
[0009] 2) Powder A is dispersed in ethanol to obtain solution A. Vanadium chloride and terephthalic acid powders are added to solution A and mixed uniformly to obtain solution B. 2-4 mL of 2M hydrochloric acid is slowly dripped into solution B, and the mixture is sonicated for 15-30 minutes to obtain solution C. Solution C is subjected to a solvothermal reaction at high temperature, and the lower precipitate is collected by centrifugation and freeze-dried to obtain a powder defined as powder B.
[0010] 3) subjecting powder B to a high-temperature thermal annealing treatment to obtain a MIL-88B(V) derivative-modified MXene-based nanocomposite (MXene-MC), defined as powder C;
[0011] 4) Using powder C as the active material (the mass ratio of powder C to the total mass of the slurry is limited to 70% to 80%), polyvinylidene fluoride as the binder, conductive carbon black as the conductive agent, N-methylpyrrolidone as the solvent, and titanium foil as the current collector, MIL-88B(V) derivative-modified MXene-based supercapacitor electrodes were prepared by slurry coating method and vacuum drying.
[0012] Preferably, in the step 1), Ti3AlC2 is a mixture of Ti powder, Al powder and TiC powder in a molar ratio of 1: (1 to 1.2): 2, and is obtained by sintering at 1350 to 1450°C for 2 hours under an inert atmosphere such as argon and nitrogen. The Ti3AlC2 layered ceramic material is ground and sieved to a particle size of less than 450 mesh, and the etchant is HF, or a mixed solution of HCl and LiF.
[0013] Preferably, the conditions for liquid phase etching with the etchant in step 1) are: 35-45°C, 500-1000 rpm, 1-2 days; the conditions for low-temperature ultrasound are: 3-12°C, frequency 45KHz, 60-120 minutes; and the centrifugation conditions are: 3500-5000 rpm, 30-60 minutes.
[0014] Preferably, in step 2), the mass of powder A is 100-300 mg, the capacity of the ethanol solvent is 50-100 mL, the mass of the vanadium chloride powder is 1-3 g, and the mass of the terephthalic acid powder is 1-3 g.
[0015] Preferably, in step 2), solution C is placed in a 100-200 mL tetrafluoroethylene liner (limiting the volume of solution C in the tetrafluoroethylene liner to less than 60%) and a reactor, and transferred to a high-precision CNC drying oven for solvent thermal reaction at 100-200° C. for 24-48 hours.
[0016] Preferably, the centrifugation conditions in step 2) are: 8000-1000 rpm, 5-10 minutes; and the freeze-drying conditions are: -65--55° C., 48-72 hours.
[0017] Preferably, in step 3), the powder B is placed in a high-temperature tube furnace and heated at 2-4°C min-1 under an inert atmosphere such as argon or nitrogen. -1 Anneal at a heating rate of 600-800°C and keep warm for 2-4 hours.
[0018] Preferably, in step 4), the mass of powder C is 40-120 mg, the mass of polyvinylidene fluoride is 5-15 mg, the mass of conductive carbon black is 5-15 mg, the volume of N-methylpyrrolidone is 0.5-1 mL, and the thickness of titanium foil is 0.01-0.1 mm.
[0019] Preferably, the vacuum drying conditions in step 4) are: 80-120° C., 12-48 hours.
[0020] The present invention also provides a MIL-88B(V) derivative modified MXene-based nanocomposite material, which is obtained by the above-mentioned method for preparing the MIL-88B(V) derivative modified MXene-based nanocomposite material. The composite material is a MXene nanosheet-MIL-88B(V) derivative (VOx@C) nanothorn heterostructure, and the spindle-shaped MIL-88B(V) derivative nanothorns are uniformly distributed on the surface of single / few-layer MXene flakes to form an open three-dimensional conductive network. The size of the single / few-layer MXene flakes is limited to 5 to 10 μm, and the storage of the MIL-88B(V) derivative nanothorns is limited to 1 to 3 μm.
[0021] The present invention also provides a method for testing the performance of MXene-based supercapacitor electrodes modified with the above-mentioned MIL-88B(V) derivatives (two-electrode test system), comprising the following steps: taking a MXene-MC-based supercapacitor electrode with a diameter of 6 to 12 mm as the positive electrode; taking a certain diameter and a unit area mass of 50 to 70 mg / cm according to the capacity and mass ratio; -2 The zinc sheet was used as the negative electrode, and a zinc salt aqueous solution (zinc sulfate, zinc trifluoromethanesulfonate, etc.) or the corresponding organic electrolyte was used as the electrolyte. A two-electrode system was assembled using a CR2032 button battery shell. Shanghai Chenhua CHI660E electrochemical workstation and Blue Electric charge and discharge instrument were used. Cyclic voltammetry (CV), constant current charge and discharge (GCD), and electrochemical impedance spectroscopy (EIS) were used to test the electrode specific capacity, energy density, power density, and cycle stability.
[0022] The present invention also provides an application of the above-mentioned MIL-88B(V) derivative modified MXene-based supercapacitor electrode as an electrode material for wearable electronic energy storage devices.
[0023] Compared with existing technologies, the present invention uses a solvothermal method to anchor MIL-88B (V) on MXene nanosheets, and converts it into vanadium oxide with high redox activity through carbonization treatment. It not only maintains the two-dimensional morphology of the material, but also constructs a three-dimensional conductive network on the MXene surface, providing additional active sites for ion insertion / deinsertion, while suppressing the self-stacking phenomenon of MXene. Compared with other methods of modifying MXene reported so far, the controllable properties of metal-organic frameworks enable it to design and create layered structures that can promote rapid ion diffusion according to needs, thereby accelerating the charge and discharge process. In addition, its derivatives (such as metal oxides, metal sulfides, metal phosphides, etc.) have open and stable scaffold structures and more uniform pore distribution, which are important factors in achieving electrochemical performance. Combining the conductivity of MXene with the redox activity of MIL-88B (V), the synergistic effect can achieve an ideal balance between the two matrices. The successful development of MIL-88B(V) derivative-modified MXene-based supercapacitor electrodes will provide experimental and theoretical support for the preparation and performance research of key positive electrode materials for high-capacity zinc ion capacitors, and promote the widespread application of high-performance, safe and environmentally friendly zinc ion capacitors in wearable electronic devices and hybrid electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the SEM image of the MIL-88B(V) derivative modified MXene-based nanocomposite prepared in Example 1 of the present invention.
[0025] Figure 2 This is the XRD pattern of the MIL-88B(V) derivative modified MXene-based nanocomposite material prepared in Example 1 of the present invention.
[0026] Figure 3 This is a constant current charge and discharge curve of the two-dimensional MXene electrode prepared in Example 1 of the present invention.
[0027] Figure 4 This is a constant current charge-discharge curve of the MIL-88B(V) derivative modified MXene-based supercapacitor electrode prepared in Example 1 of the present invention.
[0028] Figure 5 This is a cyclic voltammogram of the MXene-based supercapacitor electrode modified with the MIL-88B(V) derivative prepared in Example 1 of the present invention.
[0029] Figure 6 This is a comparison chart of the specific capacities of the MXene composite electrode and the MIL-88B(V) derivative-modified MXene-based supercapacitor electrode in Example 1 of the present invention. DETAILED DESCRIPTION
[0030] The present invention is further explained below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments in this application without making creative efforts are within the scope of protection of this application.
[0031] The present invention provides a MIL-88B(V) derivative-modified MXene-based nanocomposite material and a preparation method thereof, comprising:
[0032] 1) Ti3AlC2 is etched in liquid phase using an etchant to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution is subjected to low-temperature ultrasonication under an inert atmosphere such as argon or nitrogen, and the upper suspension is collected by centrifugation to obtain a concentration of 1.0 to 8.0 mg / mL -1 The single / few-layer MXene nanosheet sol solution is freeze-dried at -65°C to -55°C for 48 to 72 hours, and the obtained single / few-layer MXene powder is defined as powder A;
[0033] 2) Powder A is dispersed in ethanol solvent to obtain solution A, vanadium chloride and terephthalic acid powders are added to solution A and mixed uniformly to obtain solution B, low-concentration hydrochloric acid is slowly dripped into solution B, and ultrasonication is performed for 15 to 30 minutes to obtain solution C, and a solvothermal reaction is performed at high temperature. The lower precipitate is collected by centrifugation and freeze-dried to obtain a powder defined as powder B;
[0034] 3) subjecting powder B to a high-temperature thermal annealing treatment to obtain a MIL-88B(V) derivative-modified MXene-based nanocomposite (MXene-MC), defined as powder C;
[0035] 4) Using powder C as the active material (the mass ratio of powder C to the total mass of the slurry is limited to 70% to 80%), polyvinylidene fluoride as the binder, conductive carbon black as the conductive agent, N-methylpyrrolidone as the solvent, and titanium foil as the current collector, MIL-88B(V) derivative-modified MXene-based supercapacitor electrodes were prepared by slurry coating method and vacuum drying.
[0036] Specifically, in step 1), the multilayer MXene nanosheet solution is prepared by etching a Ti3AlC2 ceramic material by a liquid phase etching method. The layered ceramic material Ti3AlC2 is a mixture of Ti powder, Al powder and TiC powder in a molar ratio of 1: (1-1.2): 2, and is obtained by sintering at 1350-1450°C for 2 hours under an argon atmosphere. The Ti3AlC2 layered ceramic material is ground and sieved to a particle size of less than 450 mesh. The etchant can be HF, or a mixed solution of HCl and LiF.
[0037] Specifically, the liquid phase etching conditions for preparing the multilayer MXene nanosheet solution in step 1) are: 35-45°C, 500-1000 rpm, 1-2 days; the low-temperature ultrasonic conditions for preparing the single / few-layer MXene nanosheet sol solution are: 3-12°C, frequency 45KHz, 60-120 minutes, while bubbling argon into the system; the centrifugation conditions are: 3500-5000 rpm, 30-60 minutes. The sol concentration is limited to 1.0-8.0 mg mL -1 .
[0038] Specifically, the mass of powder A required for preparing solution B in step 2) is 100-300 mg, the capacity of ethanol solvent is 50-100 mL, the mass of vanadium chloride powder is 1-3 g, and the mass of terephthalic acid powder is 1-3 g.
[0039] Specifically, in step 2), the volume concentration of hydrochloric acid added dropwise to solution B is 2 M, and the volume is 2 to 4 mL.
[0040] Specifically, solution C in step 2) is placed in a 100-200 mL tetrafluoroethylene liner (limiting the volume proportion of solution C in the tetrafluoroethylene liner to less than 60%) and a reactor, and transferred to a high-precision CNC drying oven for a solvent thermal reaction at 100-200° C. for 24-48 hours.
[0041] Specifically, the centrifugation conditions after the solvothermal reaction in step 2) are: 8000-1000 rpm, 5-10 minutes; the freeze-drying conditions for obtaining powder B are: -65--55° C., 48-72 hours.
[0042] Specifically, the powder B in step 3) was transferred to a high temperature tube furnace and heated at 2-4°C min under an argon atmosphere. -1 Anneal at a heating rate of 600-800°C and keep warm for 2-4 hours.
[0043] Specifically, the mass of powder C required for preparing the composite electrode by the slurry coating method in step 4) is 40-120 mg, the mass of polyvinylidene fluoride is 5-15 mg, the mass of conductive carbon black is 5-15 mg, the volume of N-methylpyrrolidone is 0.5-1 mL, and the thickness of the titanium foil is limited to 0.01-0.1 mm.
[0044] Specifically, the vacuum drying conditions in step 4) are: 80-120° C., 12-48 hours.
[0045] The present invention also provides a MIL-88B(V) derivative-modified MXene-based nanocomposite material, obtained using the aforementioned preparation method. This composite material comprises a MXene nanosheet-MIL-88B(V) derivative (VOx@C) nanothorn heterostructure, with spindle-shaped MIL-88B(V) derivative nanothorns uniformly distributed on the surface of single-layer / few-layer MXene flakes, forming an open three-dimensional conductive network. The composite material exhibits good specific capacity and excellent cycling performance. The preparation of MIL-88B(V) derivative-modified MXene-based zinc ion capacitor electrodes provides a more efficient, reliable, and sustainable energy storage solution for applications such as electric vehicles and consumer electronics.
[0046] The preparation process involved in the present invention has the technical characteristics of simple and clear process flow and high process stability. Its various links have been systematically optimized and designed, and the key process parameters are precisely controllable. The raw material system uses industrial-grade compounds with a wide range of sources and low cost. The process route strictly follows the principles of green chemistry, with low discharge of three wastes and easy to carry out harmless treatment. An industrial production system with excellent economy and environmental friendliness has been successfully constructed. The MIL-88B (V) derivative-modified MXene-based nanocomposite prepared by the present invention uses a solvent thermal method and thermal annealing treatment to anchor the MIL-88B (V) derivative on the surface of two-dimensional MXene nanosheets to form a three-dimensional conductive network, which provides additional active sites for ion embedding / de-embedding and suppresses the self-stacking phenomenon of MXene. The use of morphology-controllable MIL-88B (V) and its derivatives to modify MXene can directionally create a layered structure that promotes rapid ion diffusion, thereby increasing the MXene interlayer spacing and increasing the surface activation sites, which not only improves the electrical conductivity of the material, but also improves the utilization rate of its pseudocapacitive active sites, ultimately enhancing the electrochemical performance of the MXene-based composite electrode. The nanocomposite materials in the present invention can be combined in a variety of ways. MIL-88B(V) derivatives can be used to modify a variety of two-dimensional MXene nanosheets. The mechanism of this strategy in enhancing the electrochemical properties of MXene-based composite electrode materials is explored, with a focus on verifying its directional improvement effect on key indicators such as specific capacitance, cycle stability, and rate performance.
[0047] The present invention is described in detail below with reference to specific embodiments.
[0048] Example 1:
[0049] 1) 2 g of LiF was added to 20 mL of HCl with a mass concentration of 36-38% to prepare an etchant, 1 g of Ti3AlC2 was added to the etchant, and the mixture was etched at 1000 rpm at 35 ° C for 1 day. The mixture was then repeatedly centrifuged at 3500 rpm with ultrapure water until clean, and the lower precipitate was collected to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution was ultrasonicated at 10 ° C for 60 minutes under an argon atmosphere and centrifuged at 3500 rpm for 30 minutes. The upper suspension was collected to obtain a concentration of 5.0 mg mL -1 The single / few-layer MXene nanosheet sol solution was freeze-dried at -65°C for 48 hours to obtain single / few-layer MXene powder A;
[0050] 2) 100 mg of the above powder A was dispersed in 50 mL of ethanol solution to obtain solution A. 1.5 g of vanadium chloride and 1.6 g of terephthalic acid powder were added to solution A and stirred at room temperature for 30 minutes to obtain solution B. 2 mL of 2 M HCl was added at 0.01 mL / s. -1 The reaction mixture was added dropwise to solution B at a rate of 100 mL and ultrasonicated for 15 minutes to obtain solution C. Solution C was placed in a 100 mL polytetrafluoroethylene liner and a reaction kettle, and transferred to a high-precision CNC drying oven. The reaction was carried out at 120°C for 48 hours, and the mixture was repeatedly centrifuged at 10,000 rpm with anhydrous ethanol and ultrapure water until clean. The lower precipitate was collected and freeze-dried at -65°C for 48 hours to obtain powder B.
[0051] 3) The powder B was transferred to a high temperature tube furnace and heated at 2°C min -1 The annealing was carried out at a heating rate of 1000 ℃ and kept at this temperature for 2 hours to obtain a MIL-88B(V) derivative modified MXene-based nanocomposite (MXene-MC), which was defined as powder C.
[0052] 4) 100 mg of powder C, 12.5 mg of polyvinylidene fluoride, and 12.5 mg of conductive carbon black powder were respectively placed in a mortar, 0.5 mL of N-methylpyrrolidone was dropped into the mixed powder and ground until uniform to form a slightly viscous conductive slurry; the conductive slurry was evenly coated on a titanium foil with a thickness of 0.03 mm and transferred to a vacuum oven and dried at 80°C for 12 hours to obtain a MIL-88B(V) derivative-modified MXene-based supercapacitor electrode;
[0053] 5) Take a MXene-MC-based supercapacitor electrode with a diameter of 6 mm as the positive electrode, and a 12 mm diameter supercapacitor with a mass per unit area of 60 mg cm -2The zinc sheet was used as the negative electrode, 2M Zn(CF3SO3)2 solution was used as the electrolyte, and a two-electrode system was assembled using a CR2032 button battery shell. Shanghai Chenhua CHI660E electrochemical workstation and Blue Electric charge and discharge instrument were used, and CV, GCD, EIS and other methods were used for testing to calculate the electrode specific capacity, energy density, power density and cycle stability.
[0054] Figure 1 This is an SEM image of the MIL-88B(V) derivative modified MXene-based supercapacitor electrode prepared in Example 1. The MIL-88B(V) derivative nanothorns are evenly distributed on the surface of the MXene sheet, presenting a three-dimensional open structure.
[0055] Figure 2 XRD pattern of the MIL-88B(V) derivative-modified MXene-based supercapacitor electrode prepared in Example 1. Compared with pure MXene, multiple diffraction peaks representing the MIL-88B(V) derivative can be observed between 20° and 80°. The (002) peak of the MIL-88B(V) derivative-modified MXene-based nanocomposite is shifted to the right, indicating a larger interlayer spacing.
[0056] Figure 4 This is the constant current charge and discharge curve of the MIL-88B(V) derivative modified MXene-based supercapacitor electrode prepared in Example 1. Figure 3 Compared with the constant current charge-discharge curve of the MXene electrode shown in Figure 3, the MIL-88B(V) derivative modified MXene-based supercapacitor electrode prepared in Example 1 has a longer discharge time. This is because the MIL-88B(V) derivative forms a three-dimensional open conductive network on the surface of the MXene nanosheets, which not only inhibits the self-stacking of the MXene nanosheets, provides a continuous electron transfer pathway and ion diffusion channel, but also introduces more surface active sites, giving it a higher specific capacity.
[0057] Figure 5 The cyclic voltammogram of the MIL-88B(V) derivative-modified MXene-based supercapacitor electrode prepared in Example 1. The CV curve shape of the MXene-MC electrode does not change much at different scan rates, indicating good charge and discharge stability.
[0058] Figure 6 This is a comparison chart of the specific capacity of the MIL-88B(V) derivative modified MXene-based supercapacitor electrode prepared in Example 1. Calculated by constant current charge and discharge curve, the MXene-MC composite electrode has a current density of 0.05Ag -1 The discharge capacity is as high as 510.5 mAh g -1 , further increasing the current density to 0.1A g-1 After that, there is still 478.6mAh g -1 In contrast, the discharge capacity of the Ti3AlC2 electrode is less than one-eighth of that of MXene-MC (0.05A g -1 The discharge capacity is 62 mAh g -1 ).
[0059] Example 2:
[0060] 1) 4 g of LiF was added to 40 mL of HCl with a mass concentration of 36-38% to prepare an etchant, 2 g of Ti3AlC2 was added to the etchant, and the mixture was etched at 1000 rpm at 40 ° C for 1 day. The mixture was then repeatedly centrifuged at 3500 rpm with ultrapure water until clean, and the lower precipitate was collected to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution was ultrasonicated for 120 minutes at 15 ° C in an argon atmosphere and centrifuged at 3500 rpm for 30 minutes. The upper suspension was collected to obtain a concentration of 8.0 mg mL -1 The single / few-layer MXene nanosheet sol solution was freeze-dried at -55°C for 72 hours to obtain single / few-layer MXene powder A;
[0061] 2) 200 mg of the above powder A was dispersed in 50 mL of ethanol solution to obtain solution A. 3.0 g of vanadium chloride and 3.2 g of terephthalic acid powder were added to solution A and stirred at room temperature for 30 minutes to obtain solution B. 4 mL of 2 M HCl was added at 0.01 mL / min. -1 The reaction mixture was added dropwise to solution B at a rate of 100 mL and ultrasonicated for 15 minutes to obtain solution C. Solution C was placed in a 100 mL polytetrafluoroethylene liner and a reaction kettle, and transferred to a high-precision CNC drying oven. The reaction was carried out at 120°C for 48 hours, and the mixture was repeatedly centrifuged with anhydrous ethanol and ultrapure water at 10,000 rpm until clean. The lower precipitate was collected and freeze-dried at -55°C for 72 hours to obtain powder B.
[0062] 3) The powder B was transferred to a high temperature tube furnace and heated at 2°C min -1 The annealing was carried out at a heating rate of 1000 ℃ and kept at this temperature for 4 hours to obtain a MIL-88B(V) derivative modified MXene-based nanocomposite (MXene-MC), which was defined as powder C.
[0063] 4) 100 mg of powder C, 12.5 mg of polyvinylidene fluoride, and 12.5 mg of conductive carbon black powder were respectively placed in a mortar, 0.5 mL of N-methylpyrrolidone was dropped into the mixed powder and ground until uniform to form a slightly viscous conductive slurry; the conductive slurry was evenly coated on a titanium foil with a thickness of 0.03 mm and transferred to a vacuum oven and dried at 80°C for 12 hours to obtain a MIL-88B(V) derivative-modified MXene-based supercapacitor electrode;
[0064] 5) Take a MXene-MC-based supercapacitor electrode with a diameter of 6 mm as the positive electrode, and a 12 mm diameter supercapacitor with a mass per unit area of 60 mg cm -2 The zinc sheet was used as the negative electrode, 2MZn(CF3SO3)2 solution was used as the electrolyte, and a two-electrode system was assembled using a CR2032 button battery shell. Shanghai Chenhua CHI660E electrochemical workstation and Blue Electric charge and discharge instrument were used, and CV, GCD, EIS and other methods were used for testing to calculate the electrode specific capacity, energy density, power density and cycle stability.
[0065] Example 3:
[0066] 1) 2 g of LiF was added to 25 mL of HCl with a mass concentration of 36-38% to prepare an etchant. 1 g of Ti3AlC2 was added to the etchant and etched at 500 rpm at 35 ° C for 2 days. The mixture was then centrifuged repeatedly with ultrapure water at 4000 rpm until clean. The lower precipitate was collected to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution was ultrasonicated under argon atmosphere at 10 ° C for 90 minutes and centrifuged at 4500 rpm for 30 minutes. The upper suspension was collected to obtain a concentration of 6.0 mg mL -1 The single / few-layer MXene nanosheet sol solution was freeze-dried at -65°C for 48 hours to obtain single / few-layer MXene powder A;
[0067] 2) 200 mg of the above powder A was dispersed in 50 mL of ethanol solution to obtain solution A. 1.5 g of vanadium chloride and 1.6 g of terephthalic acid powder were added to solution A and stirred at room temperature for 30 minutes to obtain solution B. 2 mL of 2 M HCl was added at 0.01 mL / s. -1 The reaction mixture was added dropwise to solution B at a rate of 100 mL and ultrasonicated for 15 minutes to obtain solution C. Solution C was placed in a 100 mL polytetrafluoroethylene liner and a reaction kettle, and transferred to a high-precision CNC drying oven. The reaction was carried out at 120°C for 48 hours, and the mixture was repeatedly centrifuged at 10,000 rpm with anhydrous ethanol and ultrapure water until clean. The lower precipitate was collected and freeze-dried at -65°C for 48 hours to obtain powder B.
[0068] 3) The powder B was transferred to a high temperature tube furnace and heated at 2°C min -1 The annealing was carried out at a heating rate of 1000 °C and kept at this temperature for 2 h to obtain a MIL-88B(V) derivative modified MXene-based nanocomposite (MXene-MC), which was defined as powder C.
[0069] 4) 100 mg of powder C, 12.5 mg of polyvinylidene fluoride, and 12.5 mg of conductive carbon black powder were respectively placed in a mortar, 0.5 mL of N-methylpyrrolidone was dropped into the mixed powder and ground until uniform to form a slightly viscous conductive slurry; the conductive slurry was evenly coated on a titanium foil with a thickness of 0.03 mm and transferred to a vacuum oven and dried at 80°C for 12 hours to obtain a MIL-88B(V) derivative-modified MXene-based supercapacitor electrode;
[0070] 5) Take a MXene-MC-based supercapacitor electrode with a diameter of 6 mm as the positive electrode, and a 12 mm diameter supercapacitor with a mass per unit area of 60 mg cm -2 The zinc sheet was used as the negative electrode, 2M Zn(CF3SO3)2 solution was used as the electrolyte, and a two-electrode system was assembled using a CR2032 button battery shell. Shanghai Chenhua CHI 660E electrochemical workstation and Blue Electric charge and discharge instrument were used, and CV, GCD, EIS and other methods were used for testing to calculate the electrode specific capacity, energy density, power density and cycle stability.
[0071] Example 4:
[0072] 1) 2 g of LiF was added to 30 mL of HCl with a mass concentration of 36-38% to prepare an etchant. 1 g of Ti3AlC2 was added to the etchant and etched at 1000 rpm at 35 ° C for 1 day. The mixture was then centrifuged repeatedly with ultrapure water at 4000 rpm until clean. The lower precipitate was collected to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution was ultrasonicated for 120 minutes at 15 ° C in an argon atmosphere and centrifuged at 4000 rpm for 30 minutes. The upper suspension was collected to obtain a concentration of 4.0 mg mL -1 The single / few-layer MXene nanosheet sol solution was freeze-dried at -55°C for 72 hours to obtain single / few-layer MXene powder A;
[0073] 2) 150 mg of the above powder A was dispersed in 50 mL of ethanol solution to obtain solution A. 3.0 g of vanadium chloride and 3.2 g of terephthalic acid powder were added to solution A and stirred at room temperature for 30 minutes to obtain solution B. 2 mL of 2 M HCl was added at 0.01 mL / min. -1The reaction mixture was added dropwise to solution B at a rate of 100 mL and ultrasonicated for 15 minutes to obtain solution C. Solution C was placed in a 100 mL polytetrafluoroethylene liner and a reaction kettle, and transferred to a high-precision CNC drying oven. The reaction was carried out at 120°C for 48 hours, and the mixture was repeatedly centrifuged with anhydrous ethanol and ultrapure water at 10,000 rpm until clean. The lower precipitate was collected and freeze-dried at -55°C for 72 hours to obtain powder B.
[0074] 3) The powder B was transferred to a high temperature tube furnace and heated at 2°C min -1 The annealing was carried out at a heating rate of 1000 °C and kept at this temperature for 4 h to obtain a MIL-88B(V) derivative modified MXene-based nanocomposite (MXene-MC), which was defined as powder C.
[0075] 4) 100 mg of powder C, 12.5 mg of polyvinylidene fluoride, and 12.5 mg of conductive carbon black powder were respectively placed in a mortar, 0.5 mL of N-methylpyrrolidone was dropped into the mixed powder and ground until uniform to form a slightly viscous conductive slurry; the conductive slurry was evenly coated on a titanium foil with a thickness of 0.03 mm and transferred to a vacuum oven and dried at 80°C for 12 hours to obtain a MIL-88B(V) derivative-modified MXene-based supercapacitor electrode;
[0076] 5) Take a MXene-MC-based supercapacitor electrode with a diameter of 6 mm as the positive electrode, and a 12 mm diameter supercapacitor with a mass per unit area of 60 mg cm -2 The zinc sheet was used as the negative electrode, 2M Zn(CF3SO3)2 solution was used as the electrolyte, and a two-electrode system was assembled using a CR2032 button battery shell. Shanghai Chenhua CHI 660E electrochemical workstation and Blue Electric charge and discharge instrument were used, and CV, GCD, EIS and other methods were used for testing to calculate the electrode specific capacity, energy density, power density and cycle stability.
Claims
1. A vanadium-based metal-organic framework (MIL-88B(V)) derivative-modified MXene-based nanocomposite (abbreviated as MXene-MC) and a preparation method thereof, comprising the following steps: (1) Ti3AlC2 was etched in liquid phase using an etchant to obtain a multilayer MXene nanosheet solution. The multilayer MXene solution was sonicated at low temperature under an inert atmosphere such as argon or nitrogen, and the upper suspension was collected by centrifugation to obtain a concentration of 2.0 to 8.0 mg mL -1 The single / few-layer MXene nanosheet sol solution is freeze-dried at -65°C to -55°C for 48 to 72 hours, and the obtained single / few-layer MXene powder is defined as powder A; (2) Powder A is dispersed in an ethanol solvent to obtain a solution A, vanadium chloride and terephthalic acid powders are added to the solution A and mixed uniformly to obtain a solution B, 2 to 4 mL of 2 M hydrochloric acid is slowly dripped into the solution B, and ultrasonicated for 15 to 30 minutes to obtain a solution C, and a solvothermal reaction is carried out at a high temperature, and the lower precipitate is collected by centrifugation, and the lower precipitate is freeze-dried. The obtained powder is defined as powder B; (3) Powder B is subjected to high-temperature thermal annealing treatment to obtain a MIL-88B(V) derivative-modified MXene-based nanocomposite material (MXene-MC), which is defined as powder C.
2. The method for preparing a MIL-88B(V) derivative-modified MXene-based nanocomposite material according to claim 1, characterized in that: In the step 1), Ti3AlC2 is obtained by mixing Ti powder, Al powder and TiC powder in a molar ratio of 1: (1 to 1.2): 2, and sintering at 1350 to 1450° C. for 2 hours under an inert atmosphere such as argon or nitrogen. The Ti3AlC2 layered ceramic material is ground and sieved to a particle size of less than 450 mesh, and the etchant is HF, or a mixed solution of HCl and LiF.
3. The method for preparing a MIL-88B(V) derivative-modified MXene-based nanocomposite material according to claim 1, characterized in that: In the step 1), the conditions for liquid phase etching with the etchant are: 35-45° C., 500-1000 rpm, and 1-2 days; the conditions for low-temperature ultrasound are: 3-12° C., 45 KHz frequency, and 60-120 minutes; and the conditions for centrifugation are: 3500-5000 rpm, and 30-60 minutes.
4. The method for preparing a MIL-88B(V) derivative-modified MXene-based nanocomposite material according to claim 1, characterized in that: In the step 2), the mass of powder A is 100-300 mg, the capacity of the ethanol solvent is 50-100 mL, the mass of the vanadium chloride powder is 1-3 g, and the mass of the terephthalic acid powder is 1-3 g.
5. The method for preparing a MIL-88B(V) derivative-modified MXene-based nanocomposite material according to claim 1, characterized in that: In the step 2), solution C is placed in a 100-200 mL tetrafluoroethylene liner (the volume of solution C in the tetrafluoroethylene liner is limited to less than 60%) and a reactor, and then transferred to a high-precision CNC drying oven for a solvothermal reaction at 100-200° C. for 24-48 hours.
6. The method for preparing a MIL-88B(V) derivative-modified MXene-based nanocomposite material according to claim 1, characterized in that: The centrifugation conditions in step 2) are: 8000-1000 rpm, 5-10 minutes; the freeze-drying conditions are: -65--55° C., 48-72 hours.
7. The method for preparing a MIL-88B(V) derivative-modified MXene-based nanocomposite material according to claim 1, characterized in that: In step 3), the powder B is placed in a high-temperature tube furnace and heated at 2-4°C min-1 under an inert atmosphere such as argon or nitrogen. -1 Anneal at a heating rate of 600-800°C and keep warm for 2-4 hours.
8. A MIL-88B(V) derivative modified MXene-based nanocomposite material, characterized in that: The method for preparing a MXene-based nanocomposite material modified by a MIL-88B (V) derivative according to any one of claims 1 to 7 is used, wherein the composite material is a MXene nanosheet-MIL-88B (V) derivative (VO x @C) Nanothorn heterostructure, spindle-shaped MIL-88B(V) derivative nanothorns are uniformly distributed on the surface of single / few-layer MXene flakes, forming an open three-dimensional conductive network. The size of single / few-layer MXene flakes is limited to 5-10μm, and the storage of MIL-88B(V) derivative nanothorns is limited to 1-3μm.
9. A MIL-88B(V) derivative-modified MXene-based nanocomposite material as claimed in claim 8 is applied to a high-capacity zinc ion supercapacitor positive electrode matched with a zinc metal negative electrode.