Ammonium ion doped vanadium-based material as well as preparation method and application thereof

Abstract

The invention discloses an ammonium ion-doped vanadium-based material and a preparation method and application thereof, and belongs to the technical field of aqueous zinc ion batteries, the preparation method of the ammonium ion-doped vanadium-based material comprises the following steps: uniformly mixing and stirring an inorganic salt containing a vanadium element, a water-soluble organic matter, an acid solution, a surfactant and an ammonium salt to obtain a mixture; and carrying out a hydrothermal reaction, centrifuging, washing with water, and drying to prepare the ammonium ion doped vanadium-based material. The composite material can be obtained only by a one-step hydrothermal method; according to the method, the electrochemical performance of the material is improved, namely, the specific capacity and cycling stability of the battery are remarkably improved; and meanwhile, the disclosed preparation process of the positive electrode material has a cost advantage, large-scale production can be realized, and a feasible path is provided for industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of aqueous zinc ion batteries, and in particular relates to an ammonium ion-doped vanadium-based material, a preparation method thereof, and an application thereof. Background Art

[0002] With the continuous growth of population and economic scale, humanity's dependence on energy is deepening. The large-scale exploitation of non-renewable energy sources such as coal and oil has led to a series of problems such as energy shortages and environmental pollution. The use of renewable energy sources such as solar, wind, and tidal energy is becoming increasingly common and a development trend around the world. However, inherent limitations such as intermittent nature and uneven spatial and temporal distribution make renewable energy sources difficult to provide stable and continuous energy during use. Therefore, efficient and reliable energy storage and conversion technologies are key to achieving large-scale utilization of clean energy.

[0003] Among the various energy storage devices, aqueous zinc-ion batteries (AZIBs) have shown their excellent competitiveness. Aqueous zinc-ion batteries use abundant and stable metallic zinc as the negative electrode, and metallic zinc has a high theoretical specific capacity (820 mAh.g -1 ), low reduction potential (-0.76V vs. SHE), the electrolyte is a non-toxic, harmless and environmentally friendly aqueous solution, which is safe and stable during the charge and discharge process and can be used for large-scale energy storage. It is currently widely regarded as one of the most competitive next-generation energy storage systems.

[0004] As a key component of aqueous zinc-ion batteries, the cathode material has a direct influence on the Zn 2+ The reversible insertion / deintercalation behavior of the battery has a decisive influence on the specific capacity, rate performance and cycle stability of the battery. Among the many positive electrode materials, vanadium-based materials have multiple valence states and different crystal structures, and usually exhibit high theoretical specific capacity and significant cycle stability. Recently, there have been methods to improve the structural stability and cycle performance of vanadium-based materials by embedding metal cations into them. For example, Su et al. [Nanoscale, 2021, 13(4): 2399G2407, DOI: 10.1039 / d0nr07358j] synthesized K with high specific capacity. + K embedded in V2O5 0.5 V2O5 electrode material, at a current density of 5A·g -1 The reversible specific capacity is as high as 251 mAh g after 1000 cycles under the same conditions. -1Yang et al. [Journal of Materials Chemistry A, 2021, 9(13): 8792G8804] synthesized porous carbon-coated C@VO2(B) cathode materials by carbon coating and alkaline etching. Carbon coating and alkaline etching improved the rate performance of VO2(B). At a current density of 5A·g -1 Under these conditions, its capacity reaches 332mAh.g -1 , and still has a capacity retention rate of 84.3% after 600 cycles. However, the research results show that although the appropriate amount of metal cation doping can improve the electrochemical performance, the introduction of doped metal cations will reduce the vanadium content per unit mass, thereby having a negative impact on the specific capacity of the material.

[0005] Therefore, the existing vanadium-based materials that can be used in aqueous zinc-ion batteries cannot fully meet the demand, and the development of new high-performance vanadium-based positive electrode materials has become an urgent problem to be solved. Summary of the Invention

[0006] In response to the above technical problems, the present invention proposes an ammonium ion-doped vanadium-based material and a preparation method and application thereof.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention:

[0009] A method for preparing an ammonium ion-doped vanadium-based material comprises the following steps:

[0010] The inorganic salt containing vanadium element, water-soluble organic matter, acid solution, surfactant and ammonium salt are mixed and stirred evenly, subjected to hydrothermal reaction, and then centrifuged, washed with water and dried to prepare the ammonium ion-doped vanadium-based material.

[0011] Optionally, the usage ratio of the inorganic salt containing vanadium element, water-soluble organic matter, acid solution, surfactant and ammonium salt is: 3mmol:1mL:1mL:120mg:0.3mmol or 3mmol:1mL:1mL:120mg:1-3mmol.

[0012] Furthermore, the usage ratio of the inorganic salt containing vanadium element, water-soluble organic matter, acid solution, surfactant and ammonium salt is: 3 mmol: 1 mL: 1 mL: 120 mg: 1.5 mmol.

[0013] Optionally, the inorganic salt containing vanadium is sodium metavanadate (NaVO3);

[0014] The water-soluble organic matter is ethylene glycol;

[0015] The acid is hydrochloric acid;

[0016] The surfactant is polyvinyl pyrrolidone;

[0017] The ammonium salt is ammonium chloride.

[0018] Beneficial effect: Preparation of NH4 by hydrothermal method + Doped HNaV6O 16 4H2O nanomaterials, in which the pH environment of the solution is changed by adding hydrochloric acid, ethylene glycol acts as a reducing agent, polyvinyl pyrrolidone is used as a surfactant, and NH4Cl is added as NH4 + The source of NH4 + Doped HNaV6O 16 ·4H2O nanomaterials. Among them, NH4 + Due to its unique properties (molar mass of only 18g·mol -1 ,radius ) show significant advantages. Unlike spherical metal cations, NH4 + The tetrahedral geometry of the nanostructured ...

[0019] Furthermore, the concentration of the hydrochloric acid is 2 mol L -1 .

[0020] Optionally, the stirring process is carried out at 600 r·min -1 Stir at a speed of 30 minutes.

[0021] Optionally, the temperature during the hydrothermal reaction is 190° C. and the reaction time is 6 h.

[0022] The second technical solution of the present invention:

[0023] An ammonium ion-doped vanadium-based material is prepared by the above preparation method.

[0024] The third technical solution of the present invention:

[0025] The application of the above-mentioned ammonium ion-doped vanadium-based material in the field of aqueous zinc ion positive electrode material.

[0026] The fourth technical solution of the present invention:

[0027] An aqueous zinc ion battery, the positive electrode of which is the vanadium-based material doped with the above-mentioned ammonium ions.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] The preparation method of the present invention is simple and easy, and only requires a one-step hydrothermal process to obtain the composite material; the method improves the electrochemical performance of the material, that is, significantly improves the specific capacity and cycle stability of the battery; at the same time, the disclosed NH4 + Doped HNaV6O 16 The 4H2O cathode material preparation process has cost advantages and can be scaled up for production, providing a feasible path for industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 NH4 prepared in Example 1 + Doped HNaV6O 16 ·4H2O nanomaterials (N 0.5 X-ray powder diffraction (XRD) pattern of HNVO);

[0032] Figure 2 NH4 prepared in Example 1 + Doped HNaV6O 16 ·4H2O nanomaterials (N 0.5 N2 isothermal adsorption-desorption curve (a) and pore size distribution (b) of HNVO);

[0033] Figure 3 NH4 prepared in Example 1 + Doped HNaV6O 16 ·4H2O nanomaterials (N 0.5 N1s spectrum of X-ray photoelectron spectroscopy (XPS) of HNVO);

[0034] Figure 4 NH4 prepared in Example 1 + Doped HNaV6O 16 ·4H2O nanomaterials (N 0.5 Scanning electron microscopy (SEM) images of HNVO);

[0035] Figure 5 The NH4 doped with different contents prepared in Examples 2-3 and Comparative Examples 1-2 + HNaV6O 16 Scanning electron microscopy (SEM) images of 4H2O nanomaterials;

[0036] Figure 6The rate performance test diagram of the materials prepared in Examples 1-3 and Comparative Examples 1-2;

[0037] Figure 7 The doped NH4 prepared in Example 1 + Doped HNaV6O 16 4H2O cathode material (N 0.5 HNVO) and undoped NH4 prepared in Comparative Example 1 + Doped HNaV6O 16 ·4H2O cathode material (HNVO) at a current density of 0.5A·g -1 Cycle test chart;

[0038] Figure 8 The prepared samples of Examples 1-3 and Comparative Examples 1-2 are doped with different contents of NH4 + HNaV6O 16 4H2O cathode material at a current density of 5A·g -1 Cycle test chart. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0041] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0042] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0043] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0044] The present invention discloses a NH4 + Doped HNaV6O 16 The preparation method of 4H2O nanomaterials comprises the following steps:

[0045] Step 1: Add a certain amount of vanadium-containing inorganic salt and water-soluble organic matter to an appropriate amount of deionized water, stir for a certain period of time to uniformly distribute the raw materials, and obtain solution A;

[0046] Step 2: Add an appropriate amount of acidic solution to solution A and stir for a certain period of time to obtain solution B;

[0047] Step 3: Add an appropriate amount of surfactant to solution B and stir for a certain period of time to form an orange-yellow clear and transparent solution C;

[0048] Step 4: Add an appropriate amount of inorganic salt containing ammonium ions to solution C and stir for a certain period of time to obtain solution D;

[0049] Step 5: Transfer solution D into a Teflon-lined reactor and react in a heating device at a certain reaction temperature and time;

[0050] Step 6: The obtained product is centrifuged, washed alternately with ethanol and water several times, and then dried to obtain a solid product.

[0051] In some optional embodiments, the inorganic salt containing vanadium element selected in step 1 is sodium metavanadate, and the water-soluble organic matter is ethylene glycol, and the dissolution method of the two is 600 r·min -1 Stir at a speed of 30 minutes.

[0052] In some optional embodiments, the acidic solution selected in step 2 is 2 mol L -1 Hydrochloric acid solution, stirring mode is 600r·min -1 Stir at a speed of 30 minutes.

[0053] In some optional embodiments, the surfactant selected in step 3 is polyvinyl pyrrolidone, and the stirring mode is 600 r·min -1 Stir at a speed of 30 minutes.

[0054] In some optional embodiments, the inorganic salt containing ammonium ions selected in step 4 is ammonium chloride, and the stirring mode is 600 r·min -1 Stir at a speed of 30 minutes.

[0055] In some optional embodiments, the reaction temperature in the heating device in step five is 190° C., and the reaction time is 6 hours.

[0056] In some optional embodiments, the product obtained in step 6 is heated at 8000 r·min -1 The product was centrifuged for 5 min, washed alternately with ethanol and deionized water for 5-6 times, and dried under vacuum at 70 ° C for 24 h to obtain the final product, thereby obtaining NH4 + Doped HNaV6O 16 4H2O nanomaterials.

[0057] The present invention also discloses a NH4 prepared by the above preparation method. + Doped HNaV6O 16 4H2O nanomaterials and their applications as aqueous zinc ion cathode materials.

[0058] The raw materials used in the present invention are all purchased from the market.

[0059] The technical solution of the present invention is further illustrated by the following examples.

[0060] Example 1

[0061] A NH4 + Doped HNaV6O 16 The preparation method of 4H2O nanomaterials comprises the following steps:

[0062] Step 1: Weigh 3mmol NaVO3 and 1mL ethylene glycol (C2H6O2) and disperse them evenly in 60mL deionized water. -1 After stirring for 30 min, solution A was obtained;

[0063] Step 2: Add 1 mL of 2 mol·L to solution A dropwise. -1 The hydrochloric acid solution was stirred for 30 min to obtain solution B;

[0064] Step 3: Add 120 mg of polyvinylpyrrolidone to solution B and stir for 30 minutes to obtain solution C;

[0065] Step 4: Add 1.5 mmol of NH4Cl to solution C and stir for 30 min to obtain solution D;

[0066] Step 5: Transfer solution D to a Teflon-lined reactor and react at 190°C for 6 hours;

[0067] Step 6: The obtained product is heated at 8000 r·min -1 The product was centrifuged at 400 °C for 5 min, washed alternately with ethanol and deionized water for 5-6 times, dried under vacuum at 70 °C for 24 h, and then dried to obtain the final product, which was recorded as N 0.5 HNVO.

[0068] Example 2

[0069] The only difference from Example 1 is that in step 4, the amount of NH4Cl added is 0.3 mmol, and the final product prepared is recorded as N 0.1 HNVO.

[0070] Example 3

[0071] The only difference from Example 1 is that in step 4, the amount of NH4Cl added is 3.0 mmol, and the final product prepared is recorded as N 1.0 HNVO.

[0072] Comparative Example 1

[0073] The difference from Example 1 is that no NH4 is added + The specific preparation process includes the following steps:

[0074] Step 1: Add 3mmol NaVO3 and 1mL ethylene glycol (C2H6O2) to 60mL deionized water and heat at 600r·min -1 After stirring for 30 min, NaVO3 and C2H6O2 were evenly dispersed to obtain solution A;

[0075] Step 2: Add 1 mL of 2 mol L-1 dropwise to solution A. -1 The hydrochloric acid solution was stirred for 30 min to obtain solution B;

[0076] Step 3: Add 120 mg of polyvinylpyrrolidone to solution B and stir for 60 minutes to obtain solution C;

[0077] Step 4: Transfer solution C into a 100 mL Teflon-lined reactor and keep it in an electric forced air drying oven at 190°C for 6 h;

[0078] Step 5: At 8000r·min -1 The product was collected after centrifugation for 5 min, washed alternately with ethanol and deionized water for 5-6 times, and dried in vacuo at 70°C for 24 h to obtain the final product HNVO.

[0079] Comparative Example 2

[0080] The only difference from Example 1 is that in step 4, the amount of NH4Cl added is 0.75 mmol, and the final product prepared is recorded as N 0.25 HNVO.

[0081] Effect verification:

[0082] 1. Structural Characterization

[0083] Firstly, the phase of the sample was characterized by X-ray powder diffractometer (XRD). + Doped HNaV6O 16 Crystal structure of 4H2O sample.

[0084] Figure 1 NH4 prepared in Example 1 + Doped HNaV6O 16 ·X-ray powder diffraction (XRD) pattern of 4H2O nanomaterials; the results show that NH4 + After adding HNaV6O 16 Compared with the standard card of 4H2O, no new diffraction peaks were generated, indicating that the addition of NH4Cl did not induce HNaV6O 16 ·4H2O phase transition, from the XRD spectrum we can see that HNVO and N 0.5 The HNVO sample has good crystallinity.

[0085] Figure 2 NH4 prepared in Example 1 + Doped HNaV6O 16 N2 isothermal adsorption-desorption curve (a) and pore size distribution (b) of 4H2O nanomaterials; Figure 2 From the isotherm analysis shown in (a), we can see that NH4 + Undoped / doped HNaV6O 16 The specific surface areas of the 4H2O samples are 34.73 m 2 ·g -1 、39.62m 2 ·g -1 .like Figure 2 The pore size distribution diagram in (b) shows that the pore size distribution of both is mainly mesopores. 0.5 The HNVO sample has a larger specific surface area, and the mesoporous structure can store Zn 2+ The large number of active sites provided are more conducive to the oxidation-reduction reaction of Zn 2+ diffusion, effectively enhancing the 2+ transmission dynamics.

[0086] Figure 3NH4 prepared in Example 1 + Doped HNaV6O 16 ·N1s spectrum of X-ray photoelectron spectroscopy (XPS) of 4H2O nanomaterials; Figure 3 As shown, the two peaks at 399.6 and 400.9 eV are attributed to the protonated state (-NH4 + -) and -NH- parts, indicating the presence of NH4 in the layered structure + , proved that NH4 + Successfully doped into HNaV6O 16 ·4H2O.

[0087] Figure 4 NH4 prepared in Example 1 + Doped HNaV6O 16 Scanning electron microscopy (SEM) images of 4H2O nanomaterials;

[0088] Figure 5 The NH4 doped with different contents prepared in Examples 2-3 and Comparative Examples 1-2 + HNaV6O 16 Scanning electron microscope (SEM) image of 4H2O nanomaterials; by comparison Figure 4 and Figure 5 It can be seen that N 0.5 The length of the HNVO nanoribbons is longer than that of the HNaVO nanoribbons (mainly around 500 nm), which allows for a more complete contact area with the electrolyte.

[0089] 2. Application in aqueous zinc ion batteries

[0090] The NH4 obtained in Example 1 + Doped HNaV6O 16 4H2O nanomaterials are used as cathode materials to assemble aqueous zinc-ion batteries. The electrochemical performance of cathode materials is evaluated from the perspective of practical applications to illustrate their feasibility in practical applications.

[0091] Step 1: Conductive carbon black is used as the conductive agent, and a mixture of N-methylpyrrolidone and polyvinylidene fluoride is used as the polymer binder. -1 Zinc trifluoromethanesulfonate solution was used as the electrolyte. Carbon paper and zinc sheet were cut into discs with diameters of 8 mm and 10 mm respectively using a cutting machine, and then processed and collected for use.

[0092] Step 2: The product obtained in Example 1 (or the undoped NH4 +The nanomaterial product) is mixed with a conductive agent and a polymer binder in a mass ratio of 7:2:1, stirred evenly, and coated on carbon paper. After repeated coating and weighing, the weight of the material on the current collector is 1 mg, NH4 + Doped HNaV6O 16 The loading amount of 4H2O nanomaterial is 0.7 mg, and then it is dried in a 60℃ oven for 4 hours to obtain the positive electrode of the aqueous zinc ion battery;

[0093] Step 3: Assemble the positive electrode sheet obtained in the second step with the zinc sheet, a glass fiber separator with a diameter of 12 mm, and about 0.3 mL of electrolyte into an aqueous zinc ion battery using a Swagelok battery system.

[0094] Examples 2 and 3 and Comparative Examples 1 and 2 all adopted the above method to assemble the positive electrode of the aqueous zinc ion battery.

[0095] First, the rate performance test was performed on the aqueous zinc ion batteries prepared in Examples 1-3 and Comparative Examples 1-2.

[0096] Figure 6 The prepared samples of Examples 1-3 and Comparative Examples 1-2 are doped with different contents of NH4 + HNaV6O 16 ·4H2O cathode material rate performance test chart; Figure 6 It can be preliminarily confirmed that N 0.5 HNVO is the sample with the best performance. 0.5 HNVO electrodes at 0.2, 0.5, 1.0, 2.0 and 5.0Ag -1 The average discharge specific capacities at these current densities are 497, 486, 471, 453, and 416 mA·h·g, respectively. -1 , while the HNVO electrode at 0.2, 0.5, 1.0, 2.0 and 5.0Ag -1 The discharge specific capacities at the current densities are 354, 338, 322, 303 and 271 mA·h·g, respectively. -1 , N at each test current density 0.5 The discharge specific capacity of the HNVO electrode is much higher than that of the HNVO electrode.

[0097] Next, the aqueous zinc ion batteries obtained in Example 1 and Comparative Example 1 were subjected to a current density of 0.5 Ag. -1 Cycle test.

[0098] Figure 7 The doped NH4 prepared in Example 1 + Doped HNaV6O 16 ·4H2O positive electrode material and undoped NH4 prepared in comparative example 1+ Doped HNaV6O 16 4H2O cathode material at a current density of 0.5A·g -1 Cycle test diagram; It can be seen from the figure that the aqueous zinc ion battery N prepared in Example 1 0.5 The HNVO electrode exhibits the highest discharge capacity of 458 mA·h·g -1 After 100 cycles, the discharge capacity is 436 mA·h·g -1 , the capacity retention rate is 95%. However, the performance of HNVO electrode is poor, with the highest discharge capacity of 332mA·h·g -1 After 100 cycles, the discharge capacity is only 293 mA·h·g -1 , the capacity retention rate is 88%. The results show that the NH4 + Doped HNaV6O 16 The battery cathode prepared with 4H2O material has good stability and high specific capacity.

[0099] Finally, the samples prepared in Examples 1-3 and Comparative Examples 1-2 were doped with different contents of NH4. + HNaV6O 16 ·4H2O cathode material with a current density of 5A·g -1 Cycle test.

[0100] Figure 8 The prepared samples of Examples 1-3 and Comparative Examples 1-2 are doped with different contents of NH4 + HNaV6O 16 4H2O cathode material at a current density of 5A·g -1 Cycle test diagram; such as Figure 8 As shown, during the 2000 cycles, HNVO and N 0.5 The highest discharge capacity of HNVO electrodes is 343 mA·h·g -1 , 460mA·h·g -1 The capacity and capacity retention rate after 2000 cycles are: 298mA·h·g -1 , 86%; 416mA·h·g -1 , 90%.

[0101] The above results show that the doped NH4 prepared in Example 1 of the present invention + Doped HNaV6O 16 The aqueous zinc-ion battery prepared with 4H2O cathode material has excellent zinc storage capacity and structural stability, showing its great potential as a cathode material for aqueous zinc-ion batteries.

[0102] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing an ammonium ion-doped vanadium-based material, characterized in that: The following steps are involved: The inorganic salt containing vanadium element, water-soluble organic matter, acid solution, surfactant and ammonium salt are mixed and stirred evenly, subjected to hydrothermal reaction, and then centrifuged, washed with water and dried to prepare the ammonium ion-doped vanadium-based material.

2. The method for preparing an ammonium ion-doped vanadium-based material according to claim 1, characterized in that: The usage ratio of the inorganic salt containing vanadium, water-soluble organic matter, acid solution, surfactant and ammonium salt is: 3mmol: 1mL: 1mL: 120mg: 0.3mmol or 3mmol: 1mL: 1mL: 120mg: 1-3mmol.

3. The method for preparing an ammonium ion-doped vanadium-based material according to claim 2, characterized in that: The usage ratio of the inorganic salt containing vanadium element, water-soluble organic matter, acid solution, surfactant and ammonium salt is: 3mmol:1mL:1mL:120mg:1.5mmol.

4. The method for preparing an ammonium ion-doped vanadium-based material according to claim 1, wherein: The inorganic salt containing vanadium element is sodium metavanadate; The water-soluble organic matter is ethylene glycol; The acid is hydrochloric acid; The surfactant is polyvinyl pyrrolidone; The ammonium salt is ammonium chloride.

5. The method for preparing an ammonium ion-doped vanadium-based material according to claim 4, characterized in that: The concentration of the hydrochloric acid is 2 mol L -1 .

6. The method for preparing an ammonium ion-doped vanadium-based material according to claim 1, characterized in that: The stirring conditions are: 600 r·min -1 Stir at a speed of 30 minutes.

7. The method for preparing an ammonium ion-doped vanadium-based material according to claim 1, characterized in that: The temperature during the hydrothermal reaction was 190° C. and the reaction time was 6 h.

8. An ammonium ion-doped vanadium-based material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the ammonium ion-doped vanadium-based material as claimed in claim 8 as an aqueous zinc ion positive electrode material.

10. An aqueous zinc ion battery, characterized in that: The positive electrode is the ammonium ion-doped vanadium-based material according to claim 8.

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