Use of polyoxovanadate materials in the preparation of aqueous zinc-based positive electrodes

Abstract

The application belongs to the field of energy storage material preparation, and particularly relates to application of a polyoxovanadate material in preparation of a water-based zinc storage positive electrode, and specifically provides a preparation method of the polyoxovanadate material and the zinc storage positive electrode, wherein manganese salt and vanadium oxide are used as raw materials, through ion induction strategy, V-O coordination polyhedrons of different valence states form diversified ion insertion-extraction molecular cluster open channels and molecular cluster structures in a self-assembly process, active sites inside the molecular cluster are fully utilized, heteroatoms are introduced, and the polyoxovanadate material is synthesized. In application, the polyoxovanadate zinc storage positive electrode is composed of a conductive agent, a binder and the polyoxovanadate material, so that the problems of active material loss of the positive electrode caused by cluster material dissolution can be solved, and the cycle performance and rate performance of the battery can be significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of energy storage material preparation, specifically involving the application technology of multivanadium oxide cluster materials in the preparation of aqueous zinc storage cathodes. Background Technology

[0002] Energy issues have always been a global focus, and developing inexpensive renewable energy and advanced energy storage technologies is considered a fundamental solution. Lithium-ion batteries (LIBs), with their high energy density and cycle stability, have dominated the electrochemical energy storage field since their commercialization in the last century. However, LIBs suffer from drawbacks such as high cost and significant environmental impact, further limiting their application. Compared to LIBs, aqueous batteries, with their low cost, high safety, and high ionic conductivity, have broad application prospects. Among them, aqueous zinc-ion batteries (AZIBs) have a low redox potential (-0.76V vs. SHE) and a high theoretical specific capacity (820mAh g / g). -1 Its advantages, such as being environmentally friendly and easy to assemble, have made it one of the most competitive alternatives to lithium-ion batteries.

[0003] Currently, cathode materials for AZIBs mainly include manganese-based oxides, vanadium-based oxides, Prussian blue compounds, organic compounds, and layered compounds. Among them, Prussian blue compounds have been widely used in electrochemical energy storage due to their low cost, structural stability, simple preparation, and open framework structure, but they suffer from low capacity. Vanadium-based materials have become another potential cathode material due to their high specific capacity, but their poor cycle stability caused by easy solubility cannot be ignored. It is worth noting that manganese dioxide has multiple crystal forms. When certain crystal forms of manganese dioxide are used as cathode materials for AZIBs, they exhibit good electrochemical performance. However, manganese-based materials also have certain drawbacks. Their structure is prone to collapse during charge and discharge, and the material has poor conductivity, which limits the battery capacity. Meanwhile, polyvanadium oxide clusters exhibit high discharge specific capacity as zinc storage cathodes, but the cluster materials are highly soluble in water, causing significant capacity loss during cycling.

[0004] Current strategies for protecting the cathode of soluble materials mainly involve coating with active substances and using adsorbents. However, these methods often encounter problems with the cathode structure and ion transport due to differences in crystal structures and contact interfaces between different materials. Therefore, exploring and developing novel, poorly soluble multi-vanadium-oxygen cluster zinc storage cathode materials is of significant implications. Summary of the Invention

[0005] This invention addresses numerous shortcomings of existing technologies by providing the application of multivanadium oxide cluster materials in the preparation of aqueous zinc storage cathodes. Specifically, it provides a method for preparing the multivanadium oxide cluster material and the zinc storage cathode. Using manganese salts and vanadium oxides as raw materials, and employing an ion-induced strategy, VO coordination polyhedra with different valence states form diverse open channels and molecular cluster structures for ion insertion-extraction during self-assembly. This fully utilizes the active sites within the molecular clusters and introduces heteroatoms to synthesize the multivanadium oxide cluster material. In application, a conductive agent, binder, and multivanadium oxide cluster material are used to compose the multivanadium oxide cluster zinc storage cathode, which can solve the problem of cathode active material loss due to cluster material dissolution and significantly improve the battery's cycle performance and rate performance.

[0006] Compared to traditional positive electrode protection strategies, the main concepts of this invention are as follows:

[0007] Encapsulating nanomaterials at the molecular scale through bonding, leveraging the flexibility of polyacid clusters in molecular structure regulation, manganese-oxygen building blocks are coated onto the surface of vanadium-oxygen cluster monomolecules to inhibit dissolution. Different valence states of VO coordination polyhedra readily form diverse open channels and cluster structures for ion insertion-extraction during self-assembly, fully utilizing the active sites within the clusters. The introduction of heteroatoms effectively modulates the interaction between active sites and Zn. 2+ The interaction strength is increased, the utilization rate of active sites is improved, and the Zn content is reduced. 2+ Improving the deintercalation resistance, thereby enhancing the cycle stability of AZIBs, is of great significance and value for the design of high-performance AZIBs.

[0008] The specific technical solution of the present invention is as follows:

[0009] The application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes involves mixing vanadium-oxygen cluster materials, conductive agents, and binders in a certain proportion to form a slurry, coating it onto a current collector, and then rolling and drying it to produce a zinc storage cathode.

[0010] The mass fraction of the vanadium oxide cluster material is 30%–90%, the mass fraction of the conductive agent is 5%–50%, and the mass fraction of the binder is 5%–20%.

[0011] The specific preparation steps of the aforementioned vanadium-oxygen cluster material are as follows:

[0012] (1) Add hydroxide and V2O5 to deionized water respectively, stir thoroughly, heat and mix well to obtain mixed solution A;

[0013] V₂O₅ accounts for 30%–50% of the solute in mixture A, and hydroxide accounts for 50%–70% of the solute in mixture A; furthermore, the concentration of hydroxide in mixture A is 0.8–3 mol / L. -1 The V₂O₅ concentration is 0.1–0.5 mol / L. -1 The heating temperature is 70–95℃; the heating time is 5–30 minutes.

[0014] (2) Treat the mixed solution A prepared in step (1) with a reducing agent to obtain mixed solution B. After constant temperature, dilute with deionized water and then add KMnO4 to obtain mixed solution C. Stir and heat to react. After the reaction is completed, quickly filter the obtained solution to obtain filtrate D.

[0015] The constant temperature in step (2) is 70-95℃, and the constant temperature time is 5-30 min; the heating temperature is 70-95℃; the heating time is 60-180 min; and the solution is diluted to 150%-300% of the volume of mixed solution B.

[0016] In the above steps, the reducing agent accounts for 20% to 30% of the solute in mixed solution B, and KMnO4 accounts for 10% to 20% of the solute in mixed solution C. The above proportions are the proportions when all solutes have not reacted.

[0017] (3) Take the filtrate D obtained in step (2) and let it stand. Filter out the crystals from it, rinse with deionized water, and dry in air at room temperature to obtain the vanadium-oxygen cluster material E.

[0018] In the above process, the presence of an alkaline environment provides a basis for the self-assembly of VO polyhedra. V is completely reduced to a low valence state by a reducing agent and partially oxidized to a high valence state by KMnO4. During this process, molecules undergo self-assembly. The insoluble manganese-oxygen building blocks will encapsulate the VO polyhedra, thereby improving the solubility of the vanadium-oxygen clusters. During the self-assembly process, the vanadium-oxygen clusters form a three-dimensional structure, generating diverse active sites, thereby improving the electrochemical performance of aqueous zinc-ion batteries.

[0019] Furthermore, the hydroxide mentioned in step (1) is one or more of LiOH·H2O, NaOH, and KOH.

[0020] Furthermore, the reducing agent in step (2) is one or more of N2H4·H2SO4, Na2C2O4, and K2C2O4.

[0021] The inventors also provide a method for preparing a zinc storage cathode with multiple vanadium-oxygen clusters that are difficult to dissolve in aqueous electrolytes. The specific steps are as follows: the vanadium-oxygen cluster material is ground and mixed with a conductive agent and a binder for 30-50 minutes, evenly coated on the current collector, and dried in a vacuum drying oven to obtain the zinc storage cathode with multiple vanadium-oxygen clusters that are difficult to dissolve.

[0022] The mass fraction of the vanadium oxide cluster material is 30% to 90%, the mass fraction of the conductive agent is 5% to 50%, and the mass fraction of the binder is 5% to 20%.

[0023] Furthermore, the conductive agent is one or more of conductive graphite, conductive carbon black, conductive carbon fiber, carbon nanotubes, graphene, and their mixed conductive slurries.

[0024] Furthermore, the adhesive is one or more of PVDF, PTFE, CMC, PVA, and PEG.

[0025] Furthermore, the vacuum drying is performed in a vacuum drying oven at 60–80°C for 180–600 min.

[0026] Furthermore, the current collector is one of titanium foil, stainless steel mesh, nickel foam, and carbon cloth.

[0027] The aforementioned zinc storage cathode based on vanadium-oxygen clusters is a zinc storage cathode application technology based on the design of insoluble vanadium-oxygen clusters and cathode structure. In the related preparation process, metal oxygen cluster building blocks are used to self-assemble into insoluble cluster molecules and arrange them in a regular manner to form mixed-valence vanadium-oxygen cluster crystals, so as to realize the rapid conduction of ions and electrons in the cluster structure, and the nanoscale dispersion of clusters, conductive agents, and binders to form a uniform cathode main structure.

[0028] Compared with existing technologies, the present invention has the following advantages:

[0029] (1) This invention uses a poorly soluble polyvanadium-oxygen cluster material as the positive electrode material of AZIBs. Taking advantage of the flexibility of polyacid clusters in molecular structure regulation, a cluster molecule with a manganese-oxygen building block coated with a polyvanadium-oxygen cluster structure is designed and synthesized to inhibit the dissolution of polyvanadium-oxygen clusters, reduce the loss of active material in AZIBs during operation, and improve cycle stability and service life.

[0030] (2) The vanadium-oxygen cluster material used in this invention has a regular three-dimensional spatial structure and VO coordination polyhedra with different valence states. During self-assembly, it is easy to form diverse open channels and molecular cluster structures for ion insertion-extraction molecular clusters, making full use of the active sites inside the molecular clusters. The introduction of heteroatoms can effectively regulate the interaction between the active sites and Zn. 2+ The interaction strength is increased, the utilization rate of active sites is improved, and the Zn content is reduced. 2+This reduces insertion / extraction resistance, thereby improving the performance of AZIBs.

[0031] (3) The vanadium-oxygen cluster material used in this invention has vanadium centers of different valence states in similar coordination geometry, which delocalizes the charge carried on the cluster framework, resulting in faster electron transport and significant electrochemical activity. Attached Figure Description

[0032] Figure 1 This is the XRD pattern of the multivanadium-oxygen cluster zinc storage material prepared in Example 1.

[0033] In the figure, the top peak is the peak emitted by the test sample, and the bottom peak is the actual peak emitted by the substance.

[0034] Figure 2 These are scanning electron microscope images of the vanadium-oxygen cluster zinc storage material prepared in Example 1.

[0035] Figure a shows the observation image within the 20μm region, figure b shows the observation image within the 40μm region, and figure c shows the observation image within the 100μm region.

[0036] Figure 3 The AZIBs assembled from the multivanadium-oxygen cluster zinc storage cathode prepared in Example 1 were used at a current density of 0.2 Ag. -1 Charge-discharge curves.

[0037] Figure 4 The AZIBs assembled from the multivanadium-oxygen cluster zinc storage cathode prepared in Example 1 were used at a current density of 0.2 Ag. -1 Cyclic curve.

[0038] Figure 5 The data are rate curves of the AZIBs assembled from the multivanadium-oxygen cluster zinc storage cathode prepared in Example 1 at different current densities.

[0039] Figure 6 The AZIBs assembled from the multivanadium-oxygen cluster zinc storage cathode prepared in Example 1 were used at a current density of 2A g. -1 Long cycle curve. Detailed Implementation

[0040] The invention will be further illustrated below with specific implementation examples. These examples are only intended to provide a complete and clear explanation of the invention, and are not intended to represent all possible implementations. All other implementations created based on this invention are within the scope of protection of this invention.

[0041] Example 1

[0042] Application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes:

[0043] Under constant temperature of 95℃, 3 mL of an aqueous solution containing 5 mmol LiOH·H2O was added to 10 mL of an aqueous solution containing 2.5 mmol V2O5, and the mixture was stirred thoroughly to obtain a mixed solution.

[0044] 2.5 mmol of N2H4·H2SO4 was slowly added to the resulting mixed solution, and the solution was kept at 95℃ for 5 min to obtain a dark solution. The dark solution was diluted to 25 mL with H2O, and then 1.25 mmol of KMnO4 was added to the diluted solution, and the solution was kept at 95℃ for 90 min. The solution was quickly filtered after being kept at the constant temperature, and the filtrate was placed in a clean beaker and allowed to stand at room temperature for 12 h to obtain a mother liquor containing crystals. The crystals were filtered out from the mother liquor, washed with H2O, and dried in air at room temperature to obtain the vanadium-oxygen cluster material.

[0045] The vanadium-oxygen cluster material obtained in Example 1 was subjected to X-ray powder diffraction testing. Figure 1 As can be seen, the XRD test results are basically consistent with the single-crystal diffraction results of this cluster. Subsequently, thermogravimetric analysis, elemental analysis, manganese titration, and infrared spectroscopy were used to determine the molecular formula of the synthesized material as [H6Mn3V]. IV 15 V V 4O 46 (H2O) 12 ]·30H2O.

[0046] The vanadium-oxygen cluster material obtained in Example 1 was subjected to SEM testing. Figure 2 It can be seen that the synthesized cluster crystals have a regular polyhedral structure, indicating that the molecular-level design of the obtained material is effective. The VO coordination polyhedra form diverse migration channels, which improves the Zn... 2+ This improves the migration ability of AZIBs, thereby helping to enhance their cyclic stability.

[0047] The prepared vanadium oxide cluster material was ground and mixed with conductive carbon black and PTFE in a mass ratio of 6:3:1. A slurry of 0.1 g was prepared and evenly coated onto a stainless steel mesh current collector. The mixture was then dried in a vacuum drying oven at 60°C for 12 hours to obtain the poorly soluble vanadium oxide cluster zinc storage cathode. An aqueous zinc-ion battery was assembled using a zinc sheet as the negative electrode, a glass fiber membrane as the separator, and a 2.5 M Zn(OTf)₂ solution as the electrolyte.

[0048] Example 2

[0049] Application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes:

[0050] Under constant temperature of 85℃, 3 mL of aqueous solution containing 5 mmol NaOH was added to 10 mL of aqueous solution containing 2.5 mmol V2O5, and the mixture was stirred thoroughly to obtain a mixed solution.

[0051] 2.5 mmol of Na₂C₂O₄ was slowly added to the resulting mixed solution, and the solution was kept at 85 °C for 10 min to obtain a dark-colored solution. The dark-colored solution was diluted to 25 mL with H₂O, and then 1.25 mmol of KMnO₄ was slowly added to the diluted solution, and the solution was kept at 85 °C for 180 min. The solution was rapidly filtered after being kept at the same temperature, and the filtrate was placed in a clean beaker and allowed to stand at room temperature for 12 h to obtain a mother liquor containing crystals. The crystals were filtered out from the mother liquor, washed with H₂O, and dried in air at room temperature to obtain the vanadium-oxygen cluster material.

[0052] The vanadium oxide cluster material was ground and mixed with conductive graphite and PTFE in a mass ratio of 7:2:1. The mixture was prepared into a slurry of 0.1g and evenly coated onto the current collector. The mixture was then dried in a vacuum drying oven at 60℃ for 12h to obtain the poorly soluble vanadium oxide cluster zinc storage cathode.

[0053] Example 3

[0054] Application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes:

[0055] Under constant temperature of 95℃, 3 mL of aqueous solution containing 5 mmol KOH was added to 10 mL of aqueous solution containing 2.5 mmol V2O5, and the mixture was stirred thoroughly to obtain a mixed solution.

[0056] 2.5 mmol of K₂C₂O₄ was slowly added to the resulting mixed solution. After the addition of the reducing agent was complete, the mixed solution was kept at 95 °C for 5 min to obtain a dark solution. The dark solution was diluted to 25 mL with H₂O, and then 1.25 mmol of KMnO₄ was slowly added to the diluted solution. The solution was then kept at 95 °C for 90 min. The solution was quickly filtered after being kept at the same temperature, and the filtrate was placed in a clean beaker and allowed to stand at room temperature for 12 h to obtain a mother liquor containing crystals. The crystals were filtered out from the mother liquor, washed with H₂O, and dried in air at room temperature to obtain the vanadium-oxygen cluster material.

[0057] The polyvanadium oxide cluster material was ground and mixed with graphene and PEG in a mass ratio of 6:3:1. 0.1g of the mixture was prepared and evenly coated on the current collector. The mixture was then dried in a vacuum drying oven at 60℃ for 12h to obtain the poorly soluble polyvanadium oxide cluster zinc storage cathode.

[0058] Example 4

[0059] Application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes:

[0060] Under constant temperature of 90℃, 30 mL of an aqueous solution containing 50 mmol LiOH·H2O was added to 100 mL of an aqueous solution containing 25 mmol V2O5, and the mixture was stirred thoroughly to obtain a mixed solution.

[0061] 25 mmol of N₂H₄·H₂SO₄ was slowly added to the resulting mixed solution, and the solution was kept at 90 °C for 10 min. A dark-colored solution was obtained. The dark-colored solution was diluted to 250 mL with H₂O, and then 12.5 mmol of KMnO₄ was slowly added to the diluted solution, and the solution was kept at 90 °C for 90 min. The solution was quickly filtered after being kept at the same temperature, and the filtrate was placed in a clean beaker and allowed to stand at room temperature for 12 h to obtain a mother liquor containing crystals. The crystals were filtered out from the mother liquor, washed with H₂O, and dried in air at room temperature to obtain the vanadium-oxygen cluster material.

[0062] The vanadium oxide cluster material was ground and mixed with conductive carbon black and PTFE in a mass ratio of 6:3:1. 0.1g of the mixture was prepared and evenly coated on the current collector. 0.1g of the mixture was then dried in a vacuum drying oven at 60℃ for 12h to obtain the poorly soluble vanadium oxide cluster zinc storage cathode.

[0063] Example 5

[0064] Application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes:

[0065] Under constant temperature of 90℃, 30 mL of aqueous solution containing 50 mmol NaOH was added to 100 mL of aqueous solution containing 25 mmol V2O5, and the mixture was stirred thoroughly to obtain a mixed solution.

[0066] 25 mmol of N₂H₄·H₂SO₄ was slowly added to the mixed solution, and the solution was kept at 90 °C for 5 min. A dark-colored solution was obtained. The dark-colored solution was diluted to 250 mL with H₂O, and then 12.5 mmol of KMnO₄ was slowly added to the diluted solution, and the solution was kept at 90 °C for 90 min. The solution was quickly filtered after being kept at the same temperature, and the filtrate was placed in a clean beaker and allowed to stand at room temperature for 12 h to obtain a mother liquor containing crystals. The crystals were filtered out from the mother liquor, washed with H₂O, and dried in air at room temperature to obtain the vanadium-oxygen cluster material.

[0067] A multivanadium oxide cluster material was ground and mixed with conductive graphite and PTFE in a mass ratio of 6:3:1. A slurry of 0.1 g was prepared and evenly coated onto a current collector. The mixture was then dried in a vacuum drying oven at 60°C for 12 hours to obtain the poorly soluble multivanadium oxide cluster zinc storage cathode. An aqueous zinc-ion battery was then assembled using a zinc sheet as the negative electrode, a glass fiber membrane as the separator, and a 2.5 M Zn(OTf)₂ solution as the electrolyte.

[0068] Experimental Example 1

[0069] The AZIBs prepared in Example 1 were subjected to charge-discharge cycles in a battery testing system. The voltage test range was 0.2–1.8 V, and the current density was 0.2 A g. -1 The obtained charge-discharge curves are as follows: Figure 3 As shown; from Figure 3 It can be seen that the specific capacity of the first discharge cycle can reach 122mAh g. -1 After 20 cycles, the resulting battery still has stable charge and discharge performance.

[0070] The AZIBs prepared in Example 1 were subjected to charge-discharge cycles in a battery testing system. The voltage test range was 0.2–1.8 V, and the current density was 0.2 A g. -1 The obtained charge-discharge curves are as follows: Figure 4 As shown. After 200 cycles, the battery's discharge specific capacity is 235.7 mAh g. -1 With a coulomb efficiency close to 100%, as shown in Table 1, this material has a higher discharge specific capacity and capacity retention rate compared to other cathode materials, demonstrating its good application value.

[0071] Table 1

[0072]

[0073] The AZIBs prepared in Example 1 were subjected to rate testing in a battery testing system with a voltage testing range of 0.2–1.8V. The resulting charge-discharge curves are shown below. Figure 5 As shown. The current density is 0.05 A g. -1 0.2A g -1 0.5A g -1 2A g -1 and 5Ag -1 At that time, the discharge specific capacity was 184 mAh g. -1 171mAh g -1 161mAh g -1 138mAh g -1 and 105mAh g -1 When the current density drops back to 2A g -1 0.5A g -1 and 0.2A g -1 At that time, the discharge specific capacity increased to 139 mAh g. -1 158mAh g -1 and 164mAh g -1 This indicates that the battery assembled with this material has good rate performance. As shown in Table 2, compared with other cathode materials, this material has excellent rate performance, demonstrating its superiority.

[0074] Table 2

[0075]

[0076] The AZIBs prepared in Example 1 were subjected to charge-discharge cycles in a battery testing system. The voltage test range was 0.2–1.8 V, and the current density was 2 A g. -1 The obtained charge-discharge curves are as follows: Figure 6 As shown. After 2500 cycles, the battery's discharge specific capacity is 207 mAh g. -1 The coulomb efficiency is close to 100%, indicating that the AZIBs assembled from this material have good stability, long life and high reliability.

[0077] The positive electrode sheets prepared in Examples 1-4 were subjected to solubility tests. By measuring the conductivity of the solution, it was found that changing the type of reducing agent or oxidizing agent, or even increasing the preparation volume significantly, did not cause the multivanadium oxide cluster material to dissolve. This demonstrates the stable insolubility of the material and its good application value.

[0078] Electrochemical tests were performed on Example 5 under the same conditions as in Example 1, and the data obtained were similar to those of Example 1. For the sake of brevity, these data will not be listed again. These experimental phenomena demonstrate the stable electrochemical performance of the material during its multiple preparation, highlighting its excellent application value in aqueous zinc storage cathodes.

[0079] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The description of the above embodiments can help understand the principles and methods of the present invention. However, the above embodiments are not unique and should not be construed as limiting the present invention. At the same time, those skilled in the art can make flexible changes to the specific implementation methods and application scope based on the principles and methods of the present invention.

Claims

1. The application of vanadium-oxygen cluster materials in the preparation of aqueous zinc storage cathodes, characterized by: A slurry of vanadium oxide cluster material, conductive agent and binder is prepared in a certain proportion, coated on the current collector, and then rolled and dried to produce a zinc storage positive electrode. The mass fraction of the vanadium oxide cluster material is 30% to 90%, the mass fraction of the conductive agent is 5% to 50%, and the mass fraction of the binder is 5% to 20%. The specific preparation steps of the vanadium-oxygen cluster material are as follows: (1) Add hydroxide and V2O5 to deionized water respectively, stir thoroughly, heat and mix well to obtain mixed solution A; The hydroxide is one or more selected from LiOH•H2O, NaOH, and KOH; (2) Treat the mixed solution A prepared in step (1) with a reducing agent to obtain mixed solution B. After constant temperature, dilute with deionized water and then add KMnO4 to obtain mixed solution C. Stir and heat to react. After the reaction is completed, quickly filter the obtained solution to obtain filtrate D. The reducing agent is one or more of N2H4•H2SO4, Na2C2O4, and K2C2O4; (3) Take the filtrate D obtained in step (2) and let it stand. Filter out the crystals from it, rinse with deionized water, and dry in air at room temperature to obtain the vanadium-oxygen cluster material E.

2. The application of the vanadium-oxygen cluster material according to claim 1 in the preparation of aqueous zinc storage cathodes, characterized in that: In step (1), V2O5 accounts for 30% to 50% of the solute in mixed solution A, and the amount of solute in hydroxide mixed solution A is 50% to 70%; the heating temperature is 70 to 95 ℃; and the heating time is 5 to 30 min.

3. The application of the vanadium-oxygen cluster material according to claim 1 or 2 in the preparation of aqueous zinc storage cathodes, characterized in that: In step (1), the concentration of hydroxide in mixed solution A is 0.8~3 mol L. -1 The V₂O₅ concentration was 0.1–0.5 mol / L. -1 .

4. The application of the vanadium-oxygen cluster material according to claim 1 in the preparation of aqueous zinc storage cathodes, characterized in that: In step (2), the constant temperature is 70~95 ℃ and the constant temperature time is 5~30 min; the heating temperature is 70~95 ℃ and the heating time is 60~180 min; and the solution is diluted with deionized water to 150%~300% of the volume of mixed solution B.

5. The application of the vanadium-oxygen cluster material according to claim 1 in the preparation of aqueous zinc storage cathodes, characterized in that: In step (2), the reducing agent accounts for 20% to 30% of the amount of solute in mixed solution B, and KMnO4 accounts for 10% to 20% of the amount of solute in mixed solution C.

6. The application of the vanadium-oxygen cluster material according to claim 1 in the preparation of aqueous zinc storage cathodes, characterized in that: The conductive agent is one or more of conductive graphite, conductive carbon black, conductive carbon fiber, carbon nanotubes, graphene, and their mixed conductive slurries.

7. The application of the vanadium-oxygen cluster material according to claim 1 in the preparation of aqueous zinc storage cathodes, characterized in that: The adhesive is one or more of PVDF, PTFE, CMC, PVA, and PEG.

8. The application of the vanadium-oxygen cluster material according to claim 1 in the preparation of aqueous zinc storage cathodes, characterized in that: The current collector is one of titanium foil, stainless steel mesh, nickel foam, and carbon cloth.

9. A method for preparing a zinc storage cathode with a polyvanadium oxide cluster that is difficult to dissolve in an aqueous electrolyte, characterized in that, The specific steps are as follows: Grind and mix the vanadium oxide cluster material with the conductive agent and binder for 30-50 minutes, apply it evenly to the current collector, and dry it in a vacuum drying oven to obtain the insoluble multivanadium oxide cluster zinc storage cathode. The specific preparation steps of the vanadium-oxygen cluster material are as follows: (1) Add hydroxide and V2O5 to deionized water respectively, stir thoroughly, heat and mix well to obtain mixed solution A; The hydroxide is one or more selected from LiOH•H2O, NaOH, and KOH; (2) Treat the mixed solution A prepared in step (1) with a reducing agent to obtain mixed solution B. After constant temperature, dilute with deionized water and then add KMnO4 to obtain mixed solution C. Stir and heat to react. After the reaction is completed, quickly filter the obtained solution to obtain filtrate D. The reducing agent is one or more of N2H4•H2SO4, Na2C2O4, and K2C2O4; (3) Take the filtrate D obtained in step (2) and let it stand. Filter out the crystals from it, rinse with deionized water, and dry in air at room temperature to obtain vanadium-oxygen cluster material E. The vacuum drying is performed in a vacuum drying oven at 60~80℃ for 180~600 min.

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