Quantum dot modified sheet stack nanorods, methods of making and rechargeable battery applications thereof

Abstract

The application provides a quantum dot modified sheet layer stacked nanorod and a preparation method and application thereof, a vanadium source and an organic ligand are mixed in water, V-MOFs are prepared through a hydrothermal reaction, then annealing calcination is carried out, sheet layer stacked VO2@C nanorods are prepared, finally, a tin source and L-cysteine amine are stirred and a hydrothermal reaction is carried out, and the sheet layer stacked nanorod VO2@C@SnS2 modified by quantum dots is prepared.Compared with the prior art, the sheet layer stacked nanorod VO2@C nanomaterial modified by SnS2 quantum dots is used to prepare an aluminum ion battery positive electrode, and the technical problems of the aluminum ion battery positive electrode material, such as the capacitive behavior without a stable discharge voltage platform, poor reversibility and low coulomb efficiency, sharply attenuated, low and unstable discharge capacity after several cycles, limited cycle life and the like are overcome.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-ion battery cathode material technology, specifically relating to quantum dot modified sheet-stacked vanadium dioxide@carbon@tin disulfide nanorods, their preparation methods, and their application in aluminum-ion batteries, serving as cathode materials for aluminum-ion batteries. Background Technology

[0002] The dwindling fossil fuel reserves and the resulting severe energy crisis and environmental problems have greatly spurred the development of renewable energy and energy storage devices. Today, renewable energy devices, especially state-of-the-art lithium-ion batteries, are widely used in portable electronic devices, including mobile phones, laptops, and wearable devices. Lithium-ion batteries are also considered the preferred choice for the growing large-scale energy storage systems such as smart grids and electric vehicles.

[0003] Aluminum is the most abundant metallic element in the Earth's crust. Furthermore, aluminum ions have a smaller radius compared to lithium ions, suggesting their potential application as a guest species in intercalation chemistry. Aluminum holds a prominent position due to its light weight and ability to exchange three electrons in electrochemical processes (Al). 3+ +3e - →Al). In fact, aluminum has the highest capacity, four times higher than lithium. Furthermore, it features a capacity of 2980mAh g. -1 It offers excellent capacity and quality. Furthermore, aluminum can be processed under air conditions, which provides a significant advantage in battery manufacturing, thereby greatly improving the safety level of electrochemical storage systems.

[0004] To date, studied active cathodes include metal sulfides, metal halides, metal oxides, graphite, sulfur, and conductive polymers, encompassing intercalation and conversion reactions in electrochemical processes. However, the application of these active cathode materials in aluminum-ion batteries still faces several key challenges, such as the limited capacity of graphite-based electrodes, the poor rate capacity and cycle stability of metal sulfides, and the slow reaction kinetics / polysulfide dissolution of sulfur electrodes. Metal sulfide quantum dots are prone to aggregation and volume expansion. Furthermore, the poor conductivity of metal sulfides results in insufficient rate capacity and high overpotential. Exploring novel aluminum-ion battery cathode materials with high discharge voltage plateaus and good cycle stability is currently a primary goal in the development of aluminum-ion batteries.

[0005] In addition, there are still some problems with the use of aluminum-ion batteries, such as the inability of the active material to fully contact the electrolyte, capacitive behavior without a stable discharge voltage plateau, very low discharge voltage, poor reversibility and therefore low coulombic efficiency, low and unstable discharge capacity that decays rapidly after a few cycles, limited cycle life, and structural decomposition and volume expansion caused by the intercalation of large-sized intercalation products. All of these factors lead to poor electrochemical performance and prevent the full utilization of its performance.

[0006] Therefore, it is essential to provide an aluminum ion battery cathode material with high coulombic efficiency and high cycle stability. Summary of the Invention

[0007] The purpose of this invention is to provide quantum dot-modified sheet-stacked nanorods and their preparation method. First, sheet-stacked VO2@C nanorods are prepared by hydrothermal calcination under an argon atmosphere, and then SnS2 quantum dot-modified sheet-stacked nanorod VO2@C nanomaterials are obtained by secondary hydrothermal method.

[0008] Another objective of this invention is to provide applications of quantum dot-modified, sheet-stacked nanorods for aluminum-ion batteries. The SnS2 quantum dot-modified, sheet-stacked VO2@C nanorods prepared in this invention, used as the cathode material for aluminum-ion batteries, overcomes the technical challenges of aluminum-ion battery cathode materials, such as the lack of a stable discharge voltage plateau, poor reversibility, low coulombic efficiency, rapid decay of low and unstable discharge capacity after a few cycles, and limited cycle life. The quantum dot-modified, sheet-stacked vanadium dioxide@carbon@tin disulfide nanorods of this application, when used in aluminum-ion batteries, exhibit high coulombic efficiency and high cycle stability.

[0009] The specific technical solution of this invention is as follows:

[0010] A method for preparing quantum dot-modified stacked nanorods includes the following steps:

[0011] 1) A vanadium source and an organic ligand are dispersed in water to form a mixed solution, and a hydrothermal reaction is carried out. After the reaction is completed, the solution is washed and dried to obtain V-MOFs.

[0012] 2) Calcine and anneal V-MOFs to obtain stacked VO2@C nanorods;

[0013] 3) Disperse the stacked VO2@C nanorods in water, add tin source and stir to mix; then add L-cysteine ​​and stir to mix. Perform hydrothermal reaction on the resulting mixed solution. After the reaction is completed, wash and dry to obtain quantum dot modified stacked nanorods VO2@C@SnS2.

[0014] In step 1), the molar ratio of the vanadium source to the organic ligand is 1:1 to 1:1.5, preferably 1:1;

[0015] In step 1), the concentration of the vanadium source in water is 0.06-0.2M;

[0016] The vanadium source mentioned in step 1) is selected from vanadium chloride (VCl3); the organic ligand is selected from terephthalic acid (C8H6O4);

[0017] In step 1), the dispersion refers to magnetic stirring at a speed of 600–800 rpm for a duration of 1–3 hours.

[0018] In step 1), the hydrothermal reaction temperature is 180-200℃ and the reaction time is 12-24h, preferably 180℃ for 24h.

[0019] In step 1), after the hydrothermal reaction, the product is washed and dried. The washing is performed by centrifugation, with 4 to 6 washes with water and 1 to 2 washes with ethanol. The centrifugation time is 1 to 5 minutes at 7000 to 9000 rpm, preferably 1 minute at 8000 rpm. Then, the product is dried at 40 to 80°C for 12 to 24 hours, preferably 12 hours at 60°C.

[0020] In step 2), the calcination annealing is carried out under an argon atmosphere; the calcination temperature is 450-550℃, preferably 500℃; the heating rate is 2-4℃ / min, preferably 3℃ / min; and the calcination time is 2-4h, preferably 3h.

[0021] In step 3), the ratio of VO2@C nanorods to water is 0.003 to 0.007 g / mL, preferably 0.0035 g / mL;

[0022] In step 3), the ratio of tin source to water is 0.005 to 0.017 g / mL, preferably 0.01 g / mL;

[0023] In step 3), the tin source is selected from tin dichloride dihydrate (SnCl2·2H2O);

[0024] In step 3), after adding the tin source, the mixture is stirred magnetically at a speed of 600-800 rpm for 1-3 hours.

[0025] In step 3), the ratio of L-cysteine ​​to water is 0.008 to 0.024 g / mL, preferably 0.016 g / mL;

[0026] In step 3), after adding L-cysteine, the mixture is magnetically stirred at a speed of 600-800 rpm for 1-3 hours.

[0027] In step 3), the hydrothermal reaction is carried out at a temperature of 160–180°C for 6–12 hours, preferably at 180°C for 6 hours.

[0028] In step 3), after the hydrothermal reaction, washing and drying are performed. The washing is done by centrifugal washing, with 4 to 6 washes with water and 1 to 2 washes with ethanol. The centrifugation is performed at 7000 to 9000 rpm for 1 to 5 minutes, preferably at 8000 rpm for 1 minute. Then, drying is performed at a temperature of 40 to 80°C for 12 to 24 hours, preferably at 60°C for 12 hours.

[0029] This invention utilizes the reaction of VCl3 and terephthalic acid to generate vanadium-based MOFs. Under specific calcination conditions and heating rates, a layered stacked structure is formed. Changing the preparation conditions will result in a different structure, leading to: insufficient reactive sites, resulting in decreased battery capacity; quantum dots easily accumulating within the layers, disrupting the structure and causing volume expansion and structural collapse during cycling; and structural fragmentation leading to overcharging and decreased battery cycle stability. Excessive thickness and width of the formed layers will also cause the aforementioned problems. Finally, quantum dot formation is related to the reactant ratio, and an excessive number of quantum dots can damage the material structure and cause battery overcharging.

[0030] The quantum dot-modified sheet-stacked nanorods provided by the present invention are prepared by the above method. The quantum dot-modified sheet-stacked nanorods are vanadium dioxide@carbon@tin disulfide nanorods formed by stacking nanosheets with a length of 1-4 μm, a width of 100-300 nm, and a thickness of 200-500 nm.

[0031] The present invention provides the application of quantum dot-modified stacked nanorods, in which the quantum dot-modified stacked nanorods vanadium dioxide@carbon@tin disulfide are used as active materials to prepare aluminum-ion battery cathodes, thereby preparing aluminum-ion batteries.

[0032] The specific application method is as follows:

[0033] Quantum dot-modified stacked nanorods of vanadium dioxide@carbon@tin disulfide were used as active materials. They were mixed with conductive carbon black and PVDF in a ratio of 8:1:1 or 7:2:1. The mixture was then magnetically stirred for 6-8 hours to disperse it evenly in N-methylpyrrolidone (NMP). The uniformly mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 60-80°C. After drying for 12-24 hours, the paper was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0034] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0035] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place an electrode plate, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of nickel foam, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 6 to 12 hours.

[0036] The material prepared in this invention has a layered stacked structure of VO2, which can increase the active surface area of ​​the material, inhibit the aggregation of SnS2 quantum dots, buffer the volume expansion of SnS2 quantum dots, and enhance the stability of the cathode material of aluminum-ion batteries, as well as the battery capacity. Aluminum-ion batteries have a high demand for high-capacity, high-rate performance, and durable cycle electrodes. The layered stacked nanorod composite material provided by this invention can effectively reduce the inter-layer junction contact resistance, provide a larger achievable active surface area for ion adsorption / desorption, inhibit the aggregation of SnS2 quantum dots, and buffer the volume expansion of SnS2 quantum dots; it also enhances the reversibility of the cathode material of aluminum-ion batteries and improves the coulombic efficiency, battery capacity, and cycle stability of aluminum-ion batteries.

[0037] The quantum dot-modified, layered, stacked nanorods VO2@C@SnS2 provided by this invention offer numerous active sites during charge and discharge. Their layered structure, with its large specific surface area, abundant pores, and oriented channels, facilitates electrolyte penetration into the electrode material and provides sufficient space for volume expansion and contraction during the discharge-charge process. This effectively solves the problem of large volumetric structural changes in materials during charge and discharge, improving battery cycle capacity, stability, and coulombic efficiency. SnS2 quantum dots increase defect sites on the VO2@C surface, thus providing more aluminum ion storage sites. Simultaneously, by nanostructuring the material using quantum dots, the electron and ion transport lengths are shortened, improving charge transfer kinetics and thereby enhancing electrochemical performance and battery capacity.

[0038] Compared with existing technologies, the quantum dot-modified layered stacked nanorod VO2@C@SnS2 composite material has the following structural advantages: 1. The layered stacked nanorod VO2@C structure can prevent the aggregation of active sites, has strong structural rigidity, and is resistant to structural breakage and collapse during resistance cycling; 2. The nanorods exhibit abundant slit-like channels perpendicular to the nanorod growth direction, promoting electrolyte penetration and shortening Al2O3 growth time. 3+ The diffusion distance; third, SnS2 quantum dots improve the utilization rate of active materials and reduce Al. 3+ The diffusion barrier increases capacity. Thanks to these structural advantages, the quantum dot-modified sheet-like stacked nanorod VO2@C@SnS2 composite material exhibits superior aluminum storage performance, particularly long-cycle stability and battery capacity retention. Optimized cathode morphology effectively buffers volumetric structural changes during charge and discharge, resulting in good cycle performance and stable coulombic efficiency, while simultaneously improving charge and discharge capacity. This enhances the battery's charge and discharge efficiency through improved electrode process kinetics, thereby strengthening the battery's electrochemical behavior. The raw materials are inexpensive, and the synthesis method allows for batch control. Attached Figure Description

[0039] Figure 1 SEM image of the sheet-stacked rod-shaped VO2@C nanorod material prepared in Comparative Example 1;

[0040] Figure 2 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterial prepared in Comparative Example 1;

[0041] Figure 3 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Comparative Example 2;

[0042] Figure 4 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterial prepared in Comparative Example 3;

[0043] Figure 5 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Comparative Example 4;

[0044] Figure 6 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Comparative Example 5;

[0045] Figure 7 SEM image of the sheet-stacked VO2@C nanorod material prepared in Example 1;

[0046] Figure 8 TEM image of the sheet-stacked VO2@C nanorod material prepared in Example 1;

[0047] Figure 9 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 1;

[0048] Figure 10 TEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 1;

[0049] Figure 11 SEM image of the sheet-stacked VO2@C nanorod material prepared in Example 3;

[0050] Figure 12 TEM image of the sheet-stacked VO2@C nanorod material prepared in Example 3;

[0051] Figure 13 SEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 3;

[0052] Figure 14 TEM image of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 3;

[0053] Figure 15 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 2 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Cyclic stability test results at current density;

[0054] Figure 16 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 2 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0055] Figure 17 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 3 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Cyclic stability test results at current density;

[0056] Figure 18 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 3 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0057] Figure 19The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 4 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Cyclic stability test results at current density;

[0058] Figure 20 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 4 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0059] Figure 21 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 5 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Cyclic stability test results at current density;

[0060] Figure 22 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared for Comparative Example 5 were used as cathode materials for aluminum-ion batteries at 0.3 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0061] Figure 23 The image shows the XRD pattern of the sheet-stacked VO2@C nanorod material prepared in Example 3.

[0062] Figure 24 The image shows the XRD pattern of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 3.

[0063] Figure 25 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 1 were used as cathode materials for aluminum-ion batteries at a concentration of 0.5 A g. -1 Cyclic stability test results at current density;

[0064] Figure 26 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 1 were used as cathode materials for aluminum-ion batteries at a concentration of 0.5 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0065] Figure 27 The sheet-stacked VO2@C nanorod material prepared in Example 1 was used as a cathode material for an aluminum-ion battery at a concentration of 0.5 A g. -1 Cyclic stability test results at current density;

[0066] Figure 28The sheet-stacked VO2@C nanorod material prepared in Example 1 was used as a cathode material for an aluminum-ion battery at a concentration of 0.5 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0067] Figure 29 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 3 were used as cathode materials for aluminum-ion batteries at a concentration of 0.5 A g. -1 Cyclic stability test results at current density;

[0068] Figure 30 The quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 3 were used as cathode materials for aluminum-ion batteries at a concentration of 0.5 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0069] Figure 31 The sheet-stacked VO2@C nanorod material prepared in Example 3 was used as a cathode material for an aluminum-ion battery at a concentration of 0.5 A g. -1 Cyclic stability test results at current density;

[0070] Figure 32 The sheet-stacked VO2@C nanorod material prepared in Example 3 was used as a cathode material for an aluminum-ion battery at a concentration of 0.5 A g. -1 Test graph of charge-discharge cycle performance at current density;

[0071] Figure 33 The rate performance test results of the sheet-stacked VO2@C nanorod material prepared in Example 3 as a cathode material for aluminum-ion batteries at different current densities are shown.

[0072] Figure 34 The graph shows the rate performance of the quantum dot-modified sheet-like stacked rod-shaped VO2@C@SnS2 nanomaterials prepared in Example 3 as a cathode material for aluminum-ion batteries at different current densities. Detailed Implementation

[0073] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0075] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0076] Comparative Example 1

[0077] A method for preparing quantum dot-modified stacked nanorods includes the following steps:

[0078] 1) Disperse 0.1659gVO2 and 0.3323gterephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0079] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 6 times with water and 2 times with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0080] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 500℃ for 2 hours, with a heating rate of 3℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods; their SEM images are shown below. Figure 1 As shown, due to the formation of trivalent vanadium ions between VO2 and terephthalic acid during the hydrothermal reaction, an irregular blocky structure is formed.

[0081] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, then add 0.68g of SnCl2·2H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0082] 5) Add 0.48 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 6 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 5 times with water and 2 times with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified stacked nanorods VO2@C@SnS2; its SEM image is shown below. Figure 2 As shown, the quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials were prepared, but the structure of the VO2@C nanorods was not fully formed and the amount of SnCl2·2H2O was relatively large, resulting in severe quantum dot stacking.

[0083] Comparative Example 2

[0084] A method for preparing quantum dot-modified stacked sheet nanorods includes the following steps:

[0085] 1) Disperse 0.3146g VCl3 and 0.3323g terephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0086] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 6 times with water and 2 times with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0087] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 400℃ for 1 h with a heating rate of 5℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods.

[0088] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, add 0.34g of SnCl2·2H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0089] 5) Add 0.24 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 160 °C for 6 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 6 times with water and 2 times with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified stacked nanorods VO2@C@SnS2; its SEM image is shown below. Figure 3 As shown, the quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials have incomplete sheet structures and low porosity due to the low calcination temperature and fast heating rate.

[0090] An aluminum-ion battery with excellent long-cycle performance is prepared by using the above-mentioned quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial as the active material to prepare the positive electrode of the aluminum-ion battery, thereby preparing the aluminum-ion battery.

[0091] Specifically, the quantum dot-modified stacked nanorods VO2@C@SnS2 nanomaterials prepared based on Comparative Example 2 were used as active materials. The active materials were mixed with conductive carbon black and PVDF in a ratio of 7:2:1 and then magnetically stirred for 8 hours to disperse them evenly in NMP. The uniformly mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 80°C. After drying for 24 hours, it was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0092] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0093] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place the electrode sheet prepared above, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of foamed nickel, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 12 hours.

[0094] Then, quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials were subjected to oxidation at 0.3 A g. -1 The cycle performance of the coin cell was tested at a current of 0.3 A g. -1 Charge and discharge performance tests under current, such as Figure 15 , 16 As shown, the battery capacity is low. It was found that the coulombic efficiency drops sharply after 135 cycles, indicating significant battery overcharging.

[0095] Comparative Example 3

[0096] A method for preparing quantum dot-modified stacked sheet nanorods includes the following steps:

[0097] 1) Disperse 0.3146g of VCl3 and 0.3323g of terephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0098] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 6 times with water and 2 times with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0099] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 600℃ for 6 hours, with a heating rate of 1℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods.

[0100] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, add 0.34g of SnCl2·2H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0101] 5) Add 0.24 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 12 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 6 times with water, then once with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified stacked nanorods VO2@C@SnS2; its SEM image is shown below. Figure 4 As shown, the quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials were broken due to the high calcination temperature and slow heating rate.

[0102] An aluminum-ion battery with excellent long-cycle performance is prepared by using the above-mentioned quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial as the active material to prepare the positive electrode of the aluminum-ion battery, thereby preparing the aluminum-ion battery.

[0103] Specifically, the active material was a quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial prepared based on Comparative Example 3. The active material was mixed with conductive carbon black and PVDF in a ratio of 7:2:1 and then magnetically stirred for 8 hours to disperse it evenly in NMP. The uniformly mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 80°C. After drying for 24 hours, it was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0104] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0105] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place the electrode sheet prepared above, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of foamed nickel, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 12 hours.

[0106] Then, quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials were subjected to oxidation at 0.3 A g. -1 The cycle performance of the coin cell was tested at a current of 0.3 A g. -1 Charge and discharge performance tests under current, such as Figure 17 , 18 As shown, the battery has a high capacity, but due to the unstable material structure, it is damaged due to overcharging after 50 cycles.

[0107] Comparative Example 4

[0108] A method for preparing quantum dot-modified stacked sheet nanorods includes the following steps:

[0109] 1) Disperse 0.3146g VCl3 and 0.3323g terephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0110] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 6 times with water and 2 times with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0111] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 500℃ for 3 hours, with a heating rate of 3℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods.

[0112] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, add 0.68g of SnCl2·2H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0113] 5) Add 0.48 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 12 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 6 times with water and 2 times with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified stacked nanorods VO2@C@SnS2; its SEM image is shown below. Figure 5 As shown, the quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials were prepared. The VO2@C nanorods formed a sheet structure. SnCl2·2H2O was used extensively, resulting in an excessively high concentration of quantum dots that accumulated on the surface of the sheet structure.

[0114] An aluminum-ion battery with excellent long-cycle performance is prepared by using the above-mentioned quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial as the active material to prepare the positive electrode of the aluminum-ion battery, thereby preparing the aluminum-ion battery.

[0115] Specifically, the active material was a quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial prepared based on Comparative Example 4. The active material was mixed with conductive carbon black and PVDF in a ratio of 7:2:1. After uniform mixing, the mixture was magnetically stirred for 8 hours and uniformly dispersed in NMP. The uniformly mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 80°C. After drying for 24 hours, it was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0116] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0117] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place an electrode plate, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of foamed nickel, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 12 hours.

[0118] Then, quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterials were subjected to oxidation at 0.3 A g. -1 The cycle performance of the coin cell was tested at a current of 0.3 A g. -1 Charge and discharge performance tests under current, such as Figure 19 , 20 As shown, the battery has a high capacity, but because the material is loaded with too many quantum dots, the quantum dots and aluminum ions are embedded together in the layered structure during the charging and discharging process, which damages the material. As a result, the battery is damaged due to overcharging after 30 cycles.

[0119] Comparative Example 5

[0120] A method for preparing quantum dot-modified stacked sheet nanorods includes the following steps:

[0121] 1) Disperse 0.3146g VCl3 and 0.3323g terephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0122] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 6 times with water and 2 times with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0123] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 500℃ for 2 hours, with a heating rate of 5℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods.

[0124] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, add 0.17g of SnCl2·2H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0125] 5) Add 0.24 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 200 °C for 24 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 6 times with water, then 2 times with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified stacked nanorods VO2@C@SnS2; its SEM image is shown below. Figure 6 As shown, the nanoflower-modified stacked nanorod VO2@C@SnS2 nanomaterials were prepared. Due to the excessively high reaction temperature and long reaction time of the VO2@C nanorods, nanoflowers instead of quantum dots were generated and accumulated on the surface of the stacked structure.

[0126] An aluminum-ion battery with excellent long-cycle performance is prepared by using the above-mentioned VO2@C@SnS2 nanomaterials as active materials to prepare the positive electrode of the aluminum-ion battery, thereby preparing the aluminum-ion battery.

[0127] Specifically, the nanorod VO2@C@SnS2 nanomaterials modified with nanoflowers and stacked layers, prepared based on Comparative Example 5, were used as active materials. The active materials were mixed with conductive carbon black and PVDF in a ratio of 7:2:1 and then magnetically stirred for 8 hours to disperse them evenly in NMP. The uniformly mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 80°C. After drying for 24 hours, it was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0128] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0129] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place an electrode plate, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of foamed nickel, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 12 hours.

[0130] Then, the nanoflower-modified stacked nanorod VO2@C@SnS2 nanomaterials were subjected to 0.3 A g... -1The cycle performance of the coin cell was tested at a current of 0.3 A g. -1 Charge and discharge performance tests under current, such as Figure 21 , 22 As shown, the battery has a high capacity, but because the material is loaded with a large number of nanoflowers, the nanoflower structure is destroyed during the charging and discharging process. Moreover, the VO2@C layer stacking structure is not obvious due to the excessively high heating rate. During the aluminum ion insertion and extraction process, the volume expands, causing the battery to be damaged due to overcharging after 90 cycles.

[0131] Example 1

[0132] A method for preparing quantum dot-modified stacked sheet nanorods includes the following steps:

[0133] 1) Disperse 0.3146g VCl3 and 0.3323g terephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0134] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 5 times with water and then once with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0135] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 500℃ for 2 hours, with a heating rate of 2℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods; their SEM images are shown below. Figure 7 As shown, its TEM image is as follows Figure 8 As shown;

[0136] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, add 0.34g of SnCl2·2H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0137] 5) Add 0.24 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 6 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 6 times with water and 2 times with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified stacked nanorods VO2@C@SnS2; the SEM image of the obtained quantum dot-modified stacked nanorods VO2@C@SnS2 is shown below. Figure 9 As shown, the TEM image is as follows Figure 10 As shown.

[0138] Example 2

[0139] An aluminum-ion battery with excellent long-cycle performance is prepared by using the above-mentioned quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial as the active material to prepare the positive electrode of the aluminum-ion battery, thereby preparing the aluminum-ion battery.

[0140] Specifically, the active material was a quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial prepared in Example 1, and the comparative active material was a stacked VO2@C nanomaterial prepared in Example 1. The two active materials were mixed with conductive carbon black and PVDF in a ratio of 7:2:1 and then magnetically stirred for 8 hours to disperse them evenly in NMP. The mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 80°C. After drying for 24 hours, it was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0141] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0142] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place the electrode sheet prepared above, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of foamed nickel, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 12 hours.

[0143] For the prepared button cell, at 0.5 A g -1 The cycle performance of the coin cell was tested at a current of 0.5 A g. -1 Charge and discharge performance tests under current, such as Figure 25 , 26 As shown; the stacked VO2@C nanomaterials at 0.5A g -1 The cycle performance of the coin cell was tested at a current of 0.5 A g. -1 Charge and discharge performance tests under current, such as Figure 27 , 28 As shown; under high current densities, the quantum dot-modified sheet-like stacked nanorod VO2@C@SnS2 nanomaterials exhibit high battery capacity, from Figure 25 Cyclic performance remains stable, from Figure 26 As can be seen, the quantum dot-modified, stacked nanorod VO2@C@SnS2 nanomaterials exhibit a long and stable charge-discharge plateau, which is beneficial for battery capacity accumulation. The battery capacity of the VO2@C@SnS2 nanomaterials is 147 mAh g. -1 Significantly higher than 103 mAh g of VO2@C nanomaterials -1 The battery cycle performance graph shows that the VO2@C nanomaterial has poor cycle stability. At 198 cycles, the battery exhibits obvious overcharging behavior, and the coulombic efficiency drops sharply.

[0144] Example 3

[0145] A method for preparing quantum dot-modified stacked sheet nanorods includes the following steps:

[0146] 1) Disperse 0.3146g VCl3 and 0.3323g terephthalic acid in 30mL of water, stir vigorously at 800rpm for 1h to dissolve them and form a mixed solution;

[0147] 2) The mixed solution formed in step 1) was transferred to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 180 °C for 24 h. After the reaction was completed, the mixture was centrifuged and washed at 8000 r for 1 min. The mixture was washed 5 times with water and 2 times with ethanol. The mixture was dried at 60 °C for 12 h to obtain a green powder (V-MOFs).

[0148] 3) V-MOF powder was loosely placed in a ceramic boat and calcined in a tube furnace under an argon atmosphere at 500℃ for 3 hours, with a heating rate of 3℃ / min. After calcination in the tube furnace, annealing was performed to obtain stacked VO2@C nanorods; their SEM images are shown below. Figure 11 As shown, its TEM image is as follows Figure 12 As shown; its XRD pattern is as follows. Figure 23 As shown;

[0149] 4) Disperse 0.15g of the VO2@C nanorods prepared in step 3) in 30mL of water, add 0.51g of SnCl2·H2O, stir vigorously at 800rpm for 1h to dissolve and form a mixed solution.

[0150] 5) Add 0.36 g L-cysteine ​​to the solution prepared in step 4), stir vigorously at 800 rpm for 1 h until dissolved, transfer the mixture to a 50 mL polytetrafluoroethylene reactor for hydrothermal reaction at 160 °C for 12 h. After the reaction, centrifuge and wash at 8000 rpm for 1 min; wash 6 times with water and 2 times with ethanol, and dry at 60 °C for 12 h to obtain quantum dot-modified sheet-stacked nanorods VO2@C@SnS2; the SEM image of the obtained quantum dot-modified sheet-stacked nanorods VO2@C@SnS2 is shown below. Figure 13 As shown, the TEM image is as follows Figure 14 As shown; its XRD pattern is as follows. Figure 24 As shown.

[0151] Example 4

[0152] An aluminum-ion battery with excellent long-cycle performance is prepared by using the above-mentioned quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial as the active material to prepare the positive electrode of the aluminum-ion battery, thereby preparing the aluminum-ion battery.

[0153] Specifically, the active material was a quantum dot-modified stacked nanorod VO2@C@SnS2 nanomaterial prepared in Example 3, and the comparative active material was a stacked VO2@C nanomaterial prepared in Example 3. The two active materials were mixed with conductive carbon black and PVDF in a ratio of 7:2:1 and then magnetically stirred for 8 hours to disperse them evenly in NMP. The mixed slurry was coated onto carbon paper using a coater and placed in a vacuum drying oven at 80°C. After drying for 24 hours, it was pressed into tablets using a tablet press and then cut into small circular electrode sheets using a cutting machine.

[0154] The fabricated electrode sheets were assembled into button cells in a glove box filled with high-purity argon gas, where the water and oxygen levels were both ≤0.01ppm. The aluminum electrolyte (LX-121) had an AlCl3:[EMIm]Cl molar ratio of 1.3:1. Molybdenum foil with a purity of Mo≥99.98% and a thickness of 0.02mm was cut into separator sizes using a tablet press. Aluminum sheets with a purity of Al≥99.99% and a thickness of 0.5mm were cut to electrode sheet sizes.

[0155] The specific method for assembling the battery is as follows: Place a piece of molybdenum foil on the positive electrode shell of the battery, add a drop of electrolyte, then place an electrode plate, then add a drop of electrolyte and place glass fiber, add two drops of electrolyte on the glass fiber and place an aluminum sheet as the counter electrode, then place two pieces of foamed nickel, add another drop of electrolyte, cover with the negative electrode shell, press and seal the battery with a hydraulic press, and leave it for 12 hours.

[0156] Then, quantum dot-modified, stacked nanorod VO2@C@SnS2 nanomaterials were subjected to oxidation at 0.5 A g. -1 The cycle performance of the coin cell was tested at a current of 0.5 A g. -1 Charge and discharge performance tests under current, such as Figure 29 , 30 As shown; the stacked VO2@C nanomaterials at 0.5A g -1 The cycle performance of the coin cell was tested at a current of 0.5 A g. -1 Charge and discharge performance tests under current, such as Figure 31 , 32 As shown; under high current densities, the quantum dot-modified sheet-like stacked nanorod VO2@C@SnS2 nanomaterials exhibit high battery capacity, from Figure 29 Cyclic performance remains stable, from Figure 30 As can be seen from the data, the quantum dot-modified, stacked nanorod VO2@C@SnS2 nanomaterials exhibit a long and stable charge-discharge plateau, which is beneficial for battery capacity accumulation; furthermore, the battery capacity of VO2@C@SnS2 nanomaterials is 192 mAh g. -1 Significantly higher than 138 mAh g of VO2@C nanomaterials -1 The cycle performance graph shows that the VO2@C nanomaterial has significantly poor cycle stability.

[0157] At 0.2A g -1 0.4A g -1 0.6A g -1 0.8A g -1 1.0A g -1 Rate performance was tested under varying current, and from Figure 33 It can be seen from the data that after three cycles, the stacked VO2@C nanomaterial battery cannot maintain stable cycling after returning to a low current, but from... Figure 34 As can be seen from the data, after three cycles, the quantum dot-modified sheet-stacked nanorod VO2@C@SnS2 nanomaterial battery can still cycle stably after returning to a low current density, and the battery capacity is relatively high.

[0158] The above detailed description of quantum dot-modified sheet-stacked nanorods of vanadium dioxide@carbon@tin disulfide, their preparation methods, and applications is illustrative rather than limiting. Several embodiments can be listed within the defined scope. Therefore, variations and modifications that do not depart from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preparing quantum dot-modified stacked sheet nanorods, characterized in that, The preparation method includes the following steps: 1) A vanadium source and an organic ligand are dispersed in water to form a mixed solution, and a hydrothermal reaction is carried out. After the reaction is completed, the solution is washed and dried to obtain V-MOFs. 2) Calcine and anneal V-MOFs to obtain stacked VO2@C nanorods; 3) Disperse the stacked VO2@C nanorods in water, add tin source and stir to mix; then add L-cysteine ​​amine and stir to mix. Perform hydrothermal reaction on the resulting mixed solution. After the reaction is completed, wash and dry to obtain quantum dot modified stacked nanorods VO2@C@SnS2.

2. The preparation method according to claim 1, characterized in that, In step 1), the molar ratio of the vanadium source to the organic ligand is 1:1 to 1:1.

5.

3. The preparation method according to claim 1 or 2, characterized in that, The vanadium source mentioned in step 1) is selected from vanadium chloride.

4. The preparation method according to claim 1 or 2, characterized in that, In step 1), the hydrothermal reaction temperature is 180–200°C, and the reaction time is 12–24 h.

5. The preparation method according to claim 1, characterized in that, In step 2), the calcination annealing is performed with argon as the protective gas, at a temperature of 450–550°C, a heating rate of 2–4°C / min, and a calcination time of 2–4 h.

6. The preparation method according to claim 1, characterized in that, In step 3), the ratio of VO2@C nanorods to water is 0.003 to 0.007 g / mL; the ratio of tin source to water is 0.005 to 0.017 g / mL.

7. The preparation method according to claim 1 or 6, characterized in that, In step 3), the ratio of L-cysteine ​​to water is 0.008 to 0.024 g / mL.

8. The preparation method according to claim 1, characterized in that, In step 3), the hydrothermal reaction is carried out at a temperature of 160–180°C for a reaction time of 6–12 hours.

9. A quantum dot-modified sheet-stacked nanorod prepared by the preparation method according to any one of claims 1-8.

10. An application of a quantum dot-modified sheet-like stacked nanorod prepared by the preparation method according to any one of claims 1-8, characterized in that, Used in aluminum-ion batteries.

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