MXene-modified metal ion pre-intercalated v5o 12 ·6h2o composites, methods of making and applications thereof

Abstract

This invention discloses an MXene-modified metal ion pre-intercalation V5O 12 The 6H2O composite material, its preparation method, and its application include: 1. Dispersing vanadium oxide in deionized water to obtain a dispersion; adding hydrogen peroxide aqueous solution to the dispersion, and reacting to obtain solution A; 2. Dispersing a metal ion compound and an amide-containing compound in deionized water to obtain solution B; 3. Slowly adding solution B to solution A to obtain solution C; 4. Dispersing MXene powder in solution C and stirring to obtain mixture D; 5. Transferring mixture D to a high-pressure reactor and performing a hydrothermal reaction at 120-140 °C. After the reaction is complete, cooling, and sequentially filtering, washing, and drying to obtain MXene-modified metal ion pre-intercalated V5O. 12 The 6H2O composite material, when used as an electrode material for aqueous zinc-ion batteries for energy storage applications, can output high specific capacity and has excellent cycle performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aqueous zinc ion batteries, and particularly relates to a MXene modified metal ion pre-embedded V5O 12 ·6H2O composite material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, rechargeable aqueous zinc ion batteries are considered to be the most promising competitor in the future large-scale energy storage field due to their low cost, safety and reliability, and extremely competitive energy density and power density. In view of this, researchers have carried out a large number of explorations on the design and development of high-performance aqueous zinc ion batteries. The positive electrode material, as the host for zinc ion storage and release, is a key factor directly determining the advantages and disadvantages of the electrochemical performance of the aqueous zinc ion battery. Therefore, the current research on the aqueous zinc ion battery is mainly focused on the development and optimization of high-performance positive electrode materials. The positive electrode materials currently proved to be suitable for aqueous zinc ion batteries mainly include vanadium-based compounds, manganese-based compounds, Prussian blue and its analogues, and organic compounds. In comparison, vanadium-based positive electrode materials usually show higher reversible capacity, better rate performance and longer cycle life, and are considered to be the most promising positive electrode material. Among the numerous vanadium-based compounds, layered vanadium-based materials become a research hotspot of vanadium-based positive electrodes due to their open framework structure, large interlayer distance and rich valence (V 2+ ~V 5+ ).

[0003] V5O 12 ·6H2O as a layered vanadium-based material is composed of double-layer stacked VO6 octahedra and VO5 positive pyramids and stably combined water molecules. Its interlayer distance is large, providing an open channel for the insertion / deinsertion of Zn 2+ in the aqueous zinc ion battery. In addition, the structural water molecules can act as charge shielding for Zn 2+ , reducing the electrostatic interaction between the host framework and Zn 2+ . These characteristics endow V5O 12 ·6H2O with great potential as an advanced host material for aqueous zinc ion batteries, which is expected to exhibit excellent energy storage properties. However, V5O 12 ·6H2O still has some inherent shortcomings during the energy storage process, such as poor electrical conductivity, slow Zn 2+ diffusion kinetics, and irreversible structural collapse caused by repeated Zn 2+ insertion / deinsertion during the cycle process, which leads to poor actual energy storage properties when used as a positive electrode of an aqueous zinc ion battery, limiting its further development and application.

[0004] Designing and constructing a composite material can make up for the shortcomings of V5O 12• Defects of V5O6H2O, a freestanding V5O6H2O was obtained by electrodeposition method in the literature 12 • V5O6H2O-CNTs film (International Journal of Energy Research, 2022, 46, 11470-11478), the conductive network composed of carbon nanotubes accelerates the transfer of electrons, to a certain extent, improves the conductivity of V5O6H2O. But this method has high requirements for equipment and complex process. And it just improves the conductivity of V5O6H2O by means of the conductive network of carbon nanotubes. 12 • The conductivity between V5O6H2O particles, and it does not target V5O6H2O 12 • The conductivity between V5O6H2O particles, and it does not target V5O6H2O 12 • V5O6H2O internal structure is modified, so the structure instability problem still exists in the reversible charge and discharge process.

[0005] Metal ion pre-embedding is another effective means to enhance the performance of layered vanadium oxide batteries. During the synthesis of the material, metal cations are introduced into the interlayer of the host material in a reasonable form, which can act as a "pillar" to enhance the structural stability of layered vanadium oxide and alleviate the structural damage caused by the reversible embedding / extraction of Zn 2+ In addition, the introduced metal ions can increase the interlayer spacing of the material. Studies have shown that a larger interlayer spacing is more conducive to the diffusion of zinc ions, and the number of zinc ions embedded in the interlayer is also greater, which is conducive to achieving higher reversible capacity. However, considering that ions cannot exist independently due to their own charge, the form in which metal ions exist in the interlayer is still a problem to be studied. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application aims to provide a MXene modified metal ion pre-embedded V5O6H2O composite material and a preparation method and application thereof, which improves the specific capacity and cycle performance of the aqueous zinc ion battery. 12

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A preparation method of a MXene modified metal ion pre-embedded V5O6H2O composite material, comprising the following steps: 12

[0009] Step 1: First, disperse 1-4 mmol of vanadium oxide in 20-100 mL of deionized water to obtain a dispersion liquid; then add 1-5 mL of 30% hydrogen peroxide aqueous solution to the dispersion liquid, stir to fully react, and obtain solution A; ​​

[0010] Step 2, 0.5-2 mmol of metal ion compound and 0.2-1 g of amide bond containing compound were dispersed in 10-60 mL of deionized water, stirred to fully react, and then solution B was obtained;

[0011] The metal ion compound is one of MnSO4, Co(NO3)2, CuSO4, Ni(NO3)2, ZnCl2 or Na2SO4;

[0012] Step 3, slowly add solution B to solution A, fully stir to obtain solution C;

[0013] Step 4, 20-100 mg of MXene powder was dispersed in solution C, and after fully stirring, mixed solution D was obtained;

[0014] Step 5, transfer mixed solution D to a high-pressure reaction kettle, and perform hydrothermal reaction at 120-140°C, after the reaction is completed, naturally cool to room temperature, then sequentially perform suction filtration, washing and vacuum drying to obtain MXene modified metal ion pre-embedded V5O 12 ·6H2O composite material.

[0015] Further, the vanadium oxide of step 1 is V2O5, V2O3 or VO2.

[0016] Further, the amide bond containing compound in step 2 is one of polyacrylamide, poly(hexamethylene terephthalamide), poly(hexamethylene adipamide), dimethylformamide or methylacetamide.

[0017] Further, the stirring in steps 1, 2, 3 and 4 is performed by a magnetic stirrer.

[0018] Further, the hydrothermal reaction time in step 5 is 6-12 h.

[0019] Further, the washing in step 5 is performed by alternating deionized water and anhydrous ethanol until the supernatant is clear.

[0020] Further, the temperature of vacuum drying in step 5 is 60°C, and the time is 12 h.

[0021] A MXene modified metal ion pre-embedded V5O 12 ·6H2O composite material.

[0022] A MXene modified metal ion pre-embedded V5O 12 ·6H2O composite material as a positive electrode material for aqueous zinc ion batteries.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] (1) The defects of the V5O 12 ·6H2O material in the prior art are taken as the breakthrough point, the V5O 12 ·6H2O is modified by combining the construction of a MXene-based composite material and the pre-embedding of metal ions, the internal structure of the V5O 12 ·6H2O and the particles of the V5O 12 ·6H2O are effectively modified, thereby producing a strong synergistic effect, improving the conductivity of the V5O 12 ·6H2O and the diffusion dynamics of Zn 2+ , improving the structural stability, exciting the energy storage potential of the V5O 12 ·6H2O material, and ultimately improving the defects of the V5O 12 ·6H2O. 12 ·6H2O, thereby improving the overall conductivity of the composite material, making up for the inherent defect of poor conductivity of the V5O 12 ·6H2O; secondly, the introduction of the amide bond-containing compound enables the metal ions to exist in the form of a complex between the V5O 12 ·6H2O layers, the metal ions can provide an electron acceptor empty orbital, and the carbonyl oxygen atom on the amide bond contains a lone pair of electrons to act as an electron donor, so that complexation can occur between them, enabling the metal ions to exist in the form of a complex between the vanadium oxide layers, the overall coordination compound is electrically neutral, not only reducing the electrostatic interaction between the pre-embedded metal cations and Zn 2+ , but also embedding the metal ions in the form of a complex between the V5O 12 ·6H2O layers, acting as an interlayer "pillar" to enhance the structural stability of the V5O 12 ·6H2O, relieving the structural collapse caused by the reversible insertion / extraction of Zn 2+ , increasing the interlayer spacing of the V5O 12 ·6H2O, and being conducive to the storage and transfer of Zn 2+ . Therefore, the MXene-modified metal ion pre-embedded V5O 12 ·6H2O composite material prepared by the application can output a higher specific capacity and exhibit excellent cycle performance.

[0025] (2) The application uses deionized water as a reaction solvent, does not need to use toxic organic reagents as solvents, the raw material source is abundant and environment-friendly, the reaction does not need to add a template material; and an one-step hydrothermal method is adopted, so that the preparation method is simple and easy to realize, the repeatability is high, the yield is high, the cost is low, and the problems of high equipment requirement and complex process of the existing preparation method are solved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material;

[0027] Figure 2 is MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material;

[0028] Figure 3 is MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material;

[0029] Figure 4 (a) is a short cycle performance diagram of the MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material prepared in Example 1 of the application under a 1A g -1 current density;

[0030] Figure 4 (b) is a long cycle performance diagram of the MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material prepared in Example 1 of the application under a 10A g -1 current density;

[0031] Figure 5 is MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material prepared in Comparative Example 1 of the application;

[0032] Figure 6 is MXene modified Mn 2+ pre-embedded V5O 12 ·6H2O composite material prepared in Comparative Example 1 of the application under a 1 Ag -1 current density;

[0033] Figure 7This is the MXene-modified Mn prepared in Comparative Example 2 of this invention. 2+ Pre-embedded V5O 12 • Scanning electron microscope image of the 6H2O composite material;

[0034] Figure 8 This is the MXene-modified Mn prepared in Comparative Example 2 of this invention. 2+ Pre-embedded V5O 12 ·6H2O composite material in 1 Ag -1 Short-cycle performance at current density. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0036] Example 1

[0037] Step 1: First, dissolve 2 mmol of V2O5 in 50 mL of deionized water to obtain a dispersion; then add 2 mL of 30% hydrogen peroxide aqueous solution to the dispersion and stir with a magnetic stirrer for 0.5 h at room temperature to obtain solution A.

[0038] Step 2: Disperse 1 mmol MnSO4 and 0.5 g polyacrylamide in 30 mL of deionized water and stir with a magnetic stirrer for 0.5 h to obtain solution B;

[0039] Step 3: At room temperature, slowly pour solution B into solution A and stir evenly with a magnetic stirrer to obtain solution C;

[0040] Step 4: Disperse 50 mg of MXene powder in solution C and stir vigorously with a magnetic stirrer for 10 min to obtain mixture D;

[0041] Step 5: Transfer the mixture D to a high-pressure reactor and perform a hydrothermal reaction at 120 °C for 6 h. After naturally cooling to room temperature, filter to obtain the precipitate. Then, wash alternately with deionized water and anhydrous ethanol until the supernatant is clear. Finally, dry in a vacuum drying oven at 60 °C for 12 h to obtain MXene-modified Mn. 2+ Pre-embedded V5O 12 ·6H2O composite material.

[0042] from Figure 1 The X-ray diffraction pattern shown indicates that the MXene-modified Mn prepared in Example 1... 2+ Pre-embedded V5O 12 X-ray diffraction peaks of the 6H2O composite material and V5O 12The diffraction peaks of V5O12·6H2O (JCPDS No. 45-1401) are consistent, and the sharp peaks indicate that the prepared product has high crystallinity. Notably, the strongest peak at 7.22° is slightly shifted to the left compared to the strongest peak (7.49°) in the standard card for V5O12·6H2O. According to Bragg's diffraction theorem, this indicates that the introduced Mn2+-based complex expands the V5O... 12 The interlayer spacing of ·6H2O; some new peaks located at 6.51°, 19.86°, 38.25° and 61.22° can all be attributed to MXene, indicating the successful recombination of V5O12·6H2O with MXene.

[0043] from Figure 2 The scanning electron microscope images shown indicate that the MXene-modified Mn prepared in Example 1... 2+ Pre-embedded V5O 12 The size of the 6H2O composite material is approximately 8 μm. The MXene conductive substrate has a typical accordion-like multilayer structure. Mn 2+ Pre-embedded V5O 12 The uniform growth of 6H2O nanosheets on the MXene surface reveals a robust three-dimensional interconnected network microstructure, demonstrating the successful construction of the composite material. MXene acts like a multi-parallel circuit, providing a continuous conductive path for efficient electron transport and offering some support to the material, thus mitigating irreversible structural degradation during cycling. Moreover, this unique morphology helps maintain structural stability, and the increased specific surface area facilitates initial electrolyte penetration, thereby enhancing ion transport speed during the electrochemical reaction.

[0044] from Figure 3 The transmission electron microscope image shown illustrates that the MXene-modified Mn prepared in Example 1... 2+ Pre-embedded V5O 12 The lattice fringes of the ·6H2O composite material have a spacing of 1.19 nm, corresponding to V5O. 12 The (001) plane of ·6H2O has a lattice spacing d greater than V5O. 12 The standard spacing (1.17 nm) corresponding to the (001) plane of ·6H2O further confirms that Mn 2+ The introduction of basic complexes can increase the interlayer spacing and promote Zn in the energy storage process. 2+ Storage and transfer.

[0045] As can be seen from Figure 4(a), the MXene-modified Mn prepared in Example 1 2+ Pre-embedded V5O 12 ·6H2O composite material in 1 A g -1Short-cycle performance at current density, with an initial discharge capacity of 396 mAh g⁻¹. -1 The initial charging capacity is 403 mAh g. -1 After 100 cycles, its discharge capacity remains at 359 mAh g. -1 The charging capacity remains at 363 mAh g. -1 The capacity retention rate is approximately 90%.

[0046] As can be seen from Figure 4(b), the MXene-modified Mn prepared in Example 1 2+ Pre-embedded V5O 12 ·6H2O composite material at 10 A g -1 Long-term cycling performance at current density, with an initial discharge capacity of 329 mAh g. -1 The initial charging capacity is 332 mAh g. -1 After 1500 cycles, its discharge capacity remains at 306 mAh g. -1 The charging capacity remains at 309 mAh g. -1 The capacity retention rate is approximately 93%, indicating that the composite material has excellent cycle life. Therefore, the preparation method provided in this invention can effectively prepare high-performance cathode materials suitable for aqueous zinc-ion batteries.

[0047] Example 2

[0048] Step 1: First, dissolve 1 mmol of V2O5 in 20 mL of deionized water to obtain a dispersion; then add 1 mL of 30% hydrogen peroxide aqueous solution to the dispersion and stir with a magnetic stirrer for 0.5 h at room temperature to obtain solution A.

[0049] Step 2: Disperse 0.5 mmol Co(NO3)2 and 0.2 g poly(hexamethylene terephthalamide) in 10 mL of deionized water and stir with a magnetic stirrer for 0.5 h to obtain solution B;

[0050] Step 3: At room temperature, slowly pour solution B into solution A and stir evenly with a magnetic stirrer to obtain solution C;

[0051] Step 4: Disperse 20 mg of MXene powder in solution C and stir vigorously with a magnetic stirrer for 10 min to obtain mixture D;

[0052] Step 5, transfer the mixed solution D to a high-pressure reaction kettle, first hydrothermal reaction at 130 ℃ for 8 h, after natural cooling to room temperature, suction filtration to obtain the precipitate, then washed with deionized water and anhydrous ethanol alternately until the supernatant is clear, finally dried in a vacuum drying box at 60 ℃ for 12 h, to obtain MXene modified Co 2+ Pre-embedded V5O 12 ·6H2O composite material.

[0053] MXene modified Co 2+ Pre-embedded V5O 12 MXene modified Mn 2+ Pre-embedded V5O 12 MXene modified Mn

[0054] Example 3

[0055] Step 1, first dissolve 3 mmol V2O5 in 80 mL deionized water to obtain a dispersion; then add 3 mL of 30% mass fraction hydrogen peroxide aqueous solution to the dispersion, and stir for 0.5 h at room temperature using a magnetic stirrer to obtain solution A;

[0056] Step 2, disperse 1.5 mmol CuSO4 and 0.6 g polyhexamethylene adipate in 45 mL deionized water, and stir for 0.5 h using a magnetic stirrer to obtain solution B;

[0057] Step 3, slowly pour solution B into solution A at room temperature, and stir uniformly using a magnetic stirrer to obtain solution C;

[0058] Step 4, disperse 60 mg MXene powder in solution C, and stir strongly for 10 min using a magnetic stirrer to obtain mixed solution D;

[0059] Step 5, transfer the mixed solution D to a high-pressure reaction kettle, first hydrothermal reaction at 140 ℃ for 10 h, after natural cooling to room temperature, suction filtration to obtain the precipitate, then washed with deionized water and anhydrous ethanol alternately until the supernatant is clear, finally dried in a vacuum drying box at 60 ℃ for 12 h, to obtain MXene modified Cu 2+ Pre-embedded V5O 12 ·6H2O composite material.

[0060] MXene modified Cu 2+ Pre-embedded V5O 12 MXene modified Mn 2+Pre-embedded V5O 12 The morphology of the pre-embedded V5O·6H2O composite material is also a nanosheet-coated MXene architecture.

[0061] Example 4

[0062] Step 1: First, 4 mmol V2O3 was dissolved in 100 mL of deionized water to obtain a dispersion liquid; then 5 mL of 30% hydrogen peroxide aqueous solution was added to the dispersion liquid, and the mixture was stirred at room temperature for 0.5 h using a magnetic stirrer to obtain solution A;

[0063] Step 2: 2 mmol Ni(NO3)2 and 1 g of dimethylformamide were dispersed in 60 mL of deionized water, and the mixture was stirred for 0.5 h using a magnetic stirrer to obtain solution B;

[0064] Step 3: At room temperature, solution B was slowly poured into solution A, and the mixture was stirred uniformly using a magnetic stirrer to obtain solution C;

[0065] Step 4: 100 mg of MXene powder was dispersed in solution C, and the mixture was stirred strongly for 10 min using a magnetic stirrer to obtain a mixed solution D;

[0066] Step 5: The mixed solution D was transferred to a high-pressure reaction kettle, and the mixture was hydrothermally reacted at 120°C for 12 h. After natural cooling to room temperature, the precipitate was obtained by suction filtration, and then washed with deionized water and anhydrous ethanol alternately until the supernatant was clear. Finally, the mixture was dried in a vacuum drying box at 60°C for 12 h to obtain MXene-modified Ni 2+ Pre-embedded V5O 12 ·6H2O composite material.

[0067] Example 4: MXene-modified Ni 2+ Pre-embedded V5O 12 ·6H2O composite material. 2+ Pre-embedded V5O 12 ·6H2O composite material.

[0068] Example 5

[0069] Step 1: First, 4 mmol V2O3 was dissolved in 100 mL of deionized water to obtain a dispersion liquid; then 5 mL of 30% hydrogen peroxide aqueous solution was added to the dispersion liquid, and the mixture was stirred at room temperature for 0.5 h using a magnetic stirrer to obtain solution A;

[0070] Step 2, take 1.25 mmol ZnCl2 and 0.8 g dimethylformamide dispersed in 35 mL deionized water, stirred with a magnetic stirrer for 0.5 h to obtain solution B;

[0071] Step 3, slowly pour solution B into solution A at room temperature, and stir uniformly with a magnetic stirrer to obtain solution C;

[0072] Step 4, disperse 80 mg MXene powder in solution C, and stir strongly with a magnetic stirrer for 10 min to obtain mixture D;

[0073] Step 5, transfer mixture D to a high-pressure reaction kettle, first hydrothermal reaction at 130 ℃ for 9 h, then naturally cool to room temperature, suction filtration to obtain a precipitate, then wash with deionized water and anhydrous ethanol alternately until the supernatant is clear, and finally dry in a vacuum drying box at 60 ℃ for 12 h to obtain MXene modified Zn 2+ Pre-embedded V5O 12 ·6H2O composite.

[0074] MXene modified Zn 2+ Pre-embedded V5O 12 The morphology of the MXene modified Mn 2+ Pre-embedded V5O 12 ·6H2O composite prepared in Example 1 is the same, which is also a MXene framework coated with nanosheets.

[0075] Example 6

[0076] Step 1, first dissolve 3.5 mmol VO2 in 40 mL deionized water to obtain a dispersion; then add 3 mL of 30% mass fraction hydrogen peroxide aqueous solution to the dispersion, and stir with a magnetic stirrer at room temperature for 0.5 h to obtain solution A;

[0077] Step 2, take 1.75 mmol Na2SO4 and 0.9 g methylacetamide dispersed in 20 mL deionized water, and stir with a magnetic stirrer for 0.5 h to obtain solution B;

[0078] Step 3, slowly pour solution B into solution A at room temperature, and stir uniformly with a magnetic stirrer to obtain solution C;

[0079] Step 4, disperse 90 mg MXene powder in solution C, and stir strongly with a magnetic stirrer for 10 min to obtain mixture D;

[0080] Step 5: Transfer the mixture D to a high-pressure reactor and perform a hydrothermal reaction at 140 °C for 7 h. After naturally cooling to room temperature, filter to obtain the precipitate. Then, wash alternately with deionized water and anhydrous ethanol until the supernatant is clear. Finally, dry in a vacuum drying oven at 60 °C for 12 h to obtain MXene-modified Na. + Pre-embedded V5O 12 ·6H2O composite material.

[0081] Example 6 Preparation of MXene-modified Na + Pre-embedded V5O 12 The morphology of the 6H2O composite material is similar to that of the MXene-modified Mn prepared in Example 1. 2+ Pre-embedded V5O 12 The morphology of the 6H2O composite material is the same, which is also a nanosheet-coated MXene structure.

[0082] Comparative Example 1

[0083] The difference between Comparative Example 1 and Example 1 is that the amount of MXene added in step 4 is 10 mg.

[0084] MXene-modified Mn prepared in Comparative Example 1 2+ Pre-embedded V5O 12 The morphology of the 6H2O composite material is as follows: Figure 5 As shown, in addition to observing Mn 2+ Pre-embedded V5O 12 The MXene composite material coated with 6H2O nanosheets also clearly shows an excessive amount of nanosheets scattered around it, and these nanosheets have agglomerated. This is attributed to the fact that the amount of MXene added is too small, and most of the nanosheets lose the support of the MXene substrate, thus agglomerating.

[0085] MXene-modified Mn prepared in Comparative Example 1 2+ Pre-embedded V5O 12 ·6H2O composite material in 1 A g -1 Cyclic performance at current density, such as Figure 6 As shown, its initial discharge capacity is 364 mAh g. -1 The initial charging capacity is 371 mAh g. -1 After 100 cycles, its discharge capacity is 322 mAh g. -1 The charging capacity is 324 mAh g. -1 It exhibits poorer cycling performance than the composite material prepared in Example 1.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 2 and Example 1 is that the amount of MXene added in step 4 is 120 mg.

[0088] Comparative Example 2: MXene-modified Mn 2+ Pre-embedded V5O 12 The morphology of the 6H2O composite material is as follows: Figure 7 As shown, the surface of MXene contains only a small amount of Mn. 2+ Pre-embedded V5O 12 • The 6H2O nanosheets were not tightly coated, and the layered structure of MXene was still very obvious, with a relatively smooth surface. This is attributed to the excessive amount of MXene added.

[0089] Comparative Example 2: MXene-modified Mn 2+ Pre-embedded V5O 12 ·6H2O composite material in 1 A g -1 Cyclic performance at current density, such as Figure 8 As shown, its initial discharge capacity is 325 mAh g. -1 The initial charging capacity is 314 mAh g. -1 After 100 cycles, its discharge capacity is 273 mAh g. -1 The charging capacity is 274 mAh g. -1 It exhibits poorer cycling performance than the composite material prepared in Example 1.

Claims

1. A method of preparing MXene-modified metal ion pre-intercalated V5O 12 ·6H2O composite material, characterized by, Comprising the following steps: Step 1, first take 1~4 mmol of vanadium oxide dispersed in 20~100 mL of deionized water to obtain a dispersion liquid; then take 1~5 mL of 30% mass fraction hydrogen peroxide aqueous solution and add it to the dispersion liquid, stir to fully react to obtain solution A; Step 2, take 0.5~2 mmol of metal ion compound and 0.2~1 g of amide bond containing compound dispersed in 10~60 mL of deionized water, stir to fully react to obtain solution B; The amide bond containing compound is one of polyacrylamide, poly(hexamethylene terephthalamide), poly(hexamethylene adipamide), dimethylformamide or methylacetamide; The metal ion compound is one of MnSO4, Co(NO3)2, CuSO4, Ni(NO3)2, ZnCl2 or Na2SO4; Step 3, slowly add solution B to solution A, stir thoroughly to obtain solution C; Step 4, disperse 20~100 mg of MXene powder in solution C, stir thoroughly to obtain mixture D; Step 5, transfer the mixed solution D to a high-pressure reaction kettle, and carry out a hydrothermal reaction at 120-140 ℃ for 6-12 h. After the reaction is completed, naturally cool to room temperature, and then sequentially perform suction filtration, washing, and vacuum drying to obtain a MXene modified metal ion pre-embedded V5O 12 ·6H2O composite material.

2. The MXene-modified metal ion pre-intercalated V5O 12 • a method for the preparation of MXene-modified metal ion pre-intercalated V5O The vanadium oxide of step 1 is V2O5, V2O3 or VO2.

3. The MXene-modified metal ion pre-intercalation V5O as described in claim 1 12 The preparation method of the ·6H2O composite material is characterized by, The stirring in steps 1, 2, 3 and 4 is all carried out by magnetic stirrer.

4. The MXene-modified metal ion pre-intercalation V5O as described in claim 1 12 The preparation method of the ·6H2O composite material is characterized by, The washing in step 5 is carried out by alternating deionized water and anhydrous ethanol until the supernatant is clear.

5. The MXene-modified metal ion pre-intercalation V5O 12 • method for the preparation of MXene-modified metal ion pre-intercalation V5O The temperature of vacuum drying in step 5 is 60 ℃, and the time is 12 h.

6. A MXene-modified metal ion pre-intercalated V5O10-6H2O composite material prepared according to the method of any one of claims 1-5. 12 ·6H2O composite material.

7. Use of MXene-modified metal ion pre-intercalated V5O 12 ·6H2O composite as a cathode material for aqueous zinc-ion batteries.​

Images