A high-stability solid-state zinc-vanadium battery and a preparation method thereof

Abstract

The application discloses a high-stability solid-state zinc-vanadium battery and a preparation method thereof, and belongs to the technical field of electrochemical batteries. The solid-state zinc-vanadium battery comprises a positive plate containing a vanadium-based compound, a solid-state electrolyte film and a negative plate; the solid-state electrolyte film is directly pressed from a solid-state electrolyte; and the solid-state electrolyte is prepared by mixing polyethylene glycol, a zinc salt, nano filler and water. After the positive plate containing the vanadium-based compound, the solid-state electrolyte film and the negative plate are stacked layer by layer, the stack is placed in a button cell shell or a soft package shell and directly pressed, so that the layers are bonded into an integrated whole, and a full battery device is obtained. The solid-state electrolyte film and the NH4V4O 10 The synergistic effect of the positive material effectively inhibits the dissolution problem of the vanadium-based positive electrode at a low current density, thereby significantly improving the cycle stability of the zinc-vanadium battery, and solving the technical problem that the vanadium-based positive material in the prior art is prone to structural failure at a low current density.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical battery technology, specifically relating to a highly stable solid-state zinc-vanadium battery and its preparation method. Background Technology

[0002] Zinc-ion batteries, with their advantages of high theoretical capacity, high safety, and low cost, have shown broad application prospects in large-scale energy storage and other fields. The cathode material is a key component determining the electrochemical performance of zinc-ion batteries. Among them, vanadium-based oxides are widely regarded as one of the ideal cathode materials for zinc-ion batteries due to their rich valence state variations, diverse crystal structures, high specific capacity, and good structural stability at high current densities. Currently, most vanadium-based cathode materials reported in the literature have achieved excellent cycle stability at high current densities.

[0003] However, in practical applications, especially under low current density conditions, the stability of zinc-ion batteries still faces serious challenges. Existing technologies generally employ liquid aqueous electrolytes, in which free water molecules participate in the Zn... 2+ The solvation process of the vanadium interacts with the unsaturated vanadium coordinated in the cathode material to form soluble vanadium oxyhydrate. This leads to vanadium dissolution, causing cathode structural failure; on the other hand, the dissolved vanadium species migrate to the anode, which exacerbates the corrosion of the zinc anode.

[0004] Further research revealed that the interlayer intercalation behavior of hydrated zinc ions was more pronounced at low current densities and during discharge, further exacerbating the aforementioned side reactions. Simultaneously, interlayer water molecules weaken the bond energy of the VO bonds, leading to the collapse of the vanadium oxide layered structure; while excessive free water molecules also trigger hydrogen evolution at the negative electrode and zinc dendrite growth, ultimately reducing the coulombic efficiency and cycle stability of the zinc-ion battery.

[0005] Therefore, how to suppress the synergistic deterioration effect of free water molecules in aqueous electrolytes on the positive and negative electrodes, especially to improve the cycle stability of zinc-vanadium batteries at low current densities, has become a key problem that urgently needs to be solved in the field of zinc-ion battery technology. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the primary objective of this invention is to provide a highly stable solid-state zinc-vanadium battery and its preparation method; wherein, the solid electrolyte membrane and NH4V4O 10The synergistic effect of the cathode materials effectively suppresses the dissolution problem of vanadium-based cathodes at low current densities, thereby significantly improving the cycle stability of zinc-vanadium batteries; it solves the technical problem of easy structural failure of vanadium-based cathode materials at low current densities in existing technologies. The solid-state zinc-vanadium battery has excellent rate capability and long cycle performance, and can efficiently suppress the structural collapse and vanadium dissolution problems caused by free water molecule erosion of vanadium-based cathode materials at low current densities. The preparation method involves stacking vanadium cathode sheets, solid electrolyte membranes, and zinc foil layer by layer, and then directly pressing them under low pressure in a coin cell or pouch cell to bond the layers together, thus obtaining a coin cell or pouch-type solid-state zinc-vanadium battery device, which can achieve low-cost assembly of zinc-vanadium batteries.

[0007] The objective of this invention is achieved through the following technical solution: In one aspect, a highly stable solid-state zinc-vanadium battery is provided, comprising a positive electrode containing a vanadium-based compound, a solid electrolyte membrane, and a negative electrode. The solid electrolyte membrane is formed by directly pressing a solid electrolyte; the solid electrolyte is prepared by mixing polyethylene glycol, zinc salt, nanofiller and water.

[0008] In some embodiments, the polyethylene glycol is selected from at least one of PEG2000, PEG4000, PEG6000, and PEG10000.

[0009] In some embodiments, the zinc salt is at least one of zinc trifluoromethanesulfonate, zinc sulfate, and zinc perchlorate.

[0010] In some embodiments, the nanofiller is at least one of SiO2, TiO2, and ZrO2.

[0011] In some embodiments, the mass ratio of polyethylene glycol, zinc salt, nanofiller, and water is (0.5~2):(0.5~1):(1~4):(0.5~2), preferably, the mass ratio of polyethylene glycol, zinc salt, nanofiller, and water is 1:1:1:1. The particle size of the nano-SiO2 is 30 nm, the particle size of the nano-TiO2 is 30 nm, and the particle size of the nano-ZrO2 is 30 nm.

[0012] In some embodiments, the thickness of the solid electrolyte membrane is 50 to 1000 micrometers, preferably any one of the following ranges: 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 1000, and any two of the above values.

[0013] In some embodiments, the vanadium-based compound positive electrode is a positive electrode obtained by coating a vanadium-based compound onto a current collector. Preferably, the current collector is one of carbon paper, nickel foam, copper mesh, titanium mesh, or stainless steel mesh.

[0014] In some embodiments, the vanadium-based compound includes at least one of ammonium vanadate, zinc vanadate, and vanadium pentoxide.

[0015] In some embodiments, the negative electrode is a zinc foil or zinc sheet with a thickness of 20-100 micrometers.

[0016] Secondly, a method for preparing the high-stability solid-state zinc-vanadium battery of the present invention is provided, comprising: By stacking vanadium-based compound positive electrode sheets, solid electrolyte membranes, and negative electrode sheets layer by layer, and then pressing them directly into a coin cell or soft-pack cell, the layers are bonded together to form a complete battery device.

[0017] In some embodiments, the pressure of the direct compression is 1-50 MPa.

[0018] Compared with the prior art, the beneficial effects of the present invention are: The present invention aims to solve the problems of vanadium-based cathode material dissolution, severe side reactions at the zinc anode interface, and poor battery cycle stability caused by the use of liquid aqueous electrolyte in existing zinc-vanadium batteries, especially the rapid capacity decay at low current densities, and to provide a solid-state zinc-vanadium battery with high cycle stability.

[0019] (1) Highly targeted: Starting from the structural failure mechanism of vanadium-based compound cathodes, the solid electrolyte design precisely suppresses the damage of free water to the cathode, fundamentally solving the problem of low current density dissolution of vanadium-based compound cathodes.

[0020] (2) Structural protection: The hydrogen bond network constructed by polyethylene glycol and nanofillers converts free water into bound water, preventing water molecules from bonding with the vanadium-oxygen layer. 2- The interaction between these elements maintains the structural integrity of the vanadium-based cathode.

[0021] (3) Simple process: The electrolyte preparation method is simple, the raw materials are widely available, the cost is low, and it is easy to scale up production.

[0022] (4) Excellent performance: The positive electrode reaction of solid zinc vanadium battery is V 5+ and V 4+ V 4+ and V 3+ The reversible process involves the deposition / stripping of zinc ions in the negative electrode reaction. The solid electrolyte in this invention inhibits vanadium dissolution, reduces the damage of free water molecules to the vanadium-based compound positive electrode, and avoids O2 buildup between water molecules and the vanadium layer.2- The structural collapse caused by hydrogen bonding in the crystal lattice improves the problem of easy dissolution of vanadium-based compound cathodes under low current, resulting in a longer cycle life of assembled zinc-vanadium full cells and significantly improving the cycle stability and commercial potential of zinc-vanadium batteries.

[0023] (5) The solid zinc-vanadium battery assembled in this invention has a specific performance at 0.2 A g. -1 It maintains excellent capacity retention after cycling for over 800 cycles at a current density; the assembled solid-state zinc-vanadium pouch cell achieves a capacity retention of 0.1 A g. -1 At the current density, the discharge specific capacity remained stable at approximately 130 mAh after initial activation, with no significant decay within 100 cycles, significantly improving the cycle stability of the battery.

[0024] (6) The preparation method of the present invention is simple, the raw materials are widely available and the cost is low, and it has good prospects for practical application. Attached Figure Description

[0025] Figure 1 Solid Zn || NH4V4O prepared in Example 1 10 Long cycle performance of the full battery.

[0026] Figure 2 Zn || NH4V4O prepared for Comparative Example 1 10 Long cycle performance of the full battery.

[0027] Figure 3 Solid Zn || NH4V4O prepared in Example 1 10 Rate performance of the full battery.

[0028] Figure 4 Zn || NH4V4O prepared for Comparative Example 1 10 Rate performance of the full battery.

[0029] Figure 5 Solid Zn || NH4V4O prepared in Example 1 10 The self-discharge performance of a full battery.

[0030] Figure 6 Zn || NH4V4O prepared for Comparative Example 1 10 The self-discharge performance of a full battery.

[0031] Figure 7 Zn || NH4V4O assembled for Example 1 10 The full cell and various zinc-vanadium battery systems reported in the literature were compared at 0.2 A g. -1 Comparison of long-cycle performance under current density.

[0032] Figure 8 Zn || NH4V4O as in Example 1 10 The full cell is at 0.2 mV s -1 Cyclic voltammetry (CV) curves.

[0033] Figure 9 For Comparative Example 1, Zn || NH4V4O 10 The full cell is at 0.2 mV s -1 The CV curve.

[0034] Figure 10 Zn || NH4V4O prepared in Example 2 10 Cycle performance of high-capacity pouch batteries.

[0035] Figure 11 The diagram shows a sample of the solid electrolyte 3-1 prepared in Example 3 of the raw material preparation. (a) is a clay-like solid electrolyte; (b) is a solid electrolyte membrane.

[0036] In the diagram: time; unit; charge to; discharge to; rest; current; voltage; capacity; cycle number; coulombic efficiency; NVO pouch cell; mass loading. Detailed Implementation

[0037] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0039] Preparation of blank electrolyte 7.27 g of zinc trifluoromethanesulfonate was added to 10 mL of ultrapure water and stirred to dissolve, thus preparing 10 mL of 2 mol / L zinc trifluoromethanesulfonate electrolyte.

[0040] Raw material preparation example 1 NH4V4O 10Preparation: Using a 500-mesh stainless steel mesh as the positive electrode current collector and zinc foil as the negative electrode current collector, NH4V4O was synthesized via a common hydrothermal reaction. 10 1.17 g of NH4VO3 was dissolved in 35 mL of ultrapure water at 80 °C to obtain a pale yellow solution. Then, 1.891 g of H2C2O4·2H2O was added, and the mixture was stirred magnetically until it turned dark green. The solution was then transferred to a 50 mL high-pressure reactor and stored in an oven at 140 °C for 48 h to obtain NH4V4O. 10 After cooling, the precipitate was washed multiple times with ultrapure water and collected. The final product was then vacuum dried at 80 °C for 24 h.

[0041] Raw material preparation example 2 Preparation of positive electrode: 70% of the active material NH4V4O 10 20% of the conductive agent Super P and 10% of the polyvinylidene fluoride (PVDF) binder were thoroughly mixed. The slurry was then uniformly coated onto a 500-mesh stainless steel mesh current collector using a scraper, and then vacuum dried at 80 °C for 12 h to obtain the positive electrode sheet.

[0042] Raw material preparation example 3 Preparation of solid electrolyte membrane: Add 2 g of polyethylene glycol to 2 g of ultrapure water, then add 2 g of zinc salt and stir to dissolve. Then add 2 g of nanofiller in batches and stir (0.3 g / batch) until a clay-like solid electrolyte is formed. Then weigh 0.4 g of solid electrolyte, put it into a silicone mold with a diameter of 16 mm and a thickness of 1 mm, and flatten it to obtain the solid electrolyte membrane.

[0043] Table 1

[0044] Raw material preparation example 4 Preparation of solid electrolyte membrane: PEG4000 was added to ultrapure water, and then zinc trifluoromethanesulfonate was added and stirred to dissolve. SiO2 was added in batches and stirred until a clay-like solid electrolyte was formed. Then, 0.4 g of solid electrolyte was weighed and placed into a silicone mold with a diameter of 16 mm and a thickness of 1 mm, and flattened to obtain the solid electrolyte membrane.

[0045] Table 2

[0046] Example 1 Assembly of solid-state zinc-vanadium batteries: The positive electrode sheet prepared in Example 1 of raw material preparation was cut into dendritic 12mm electrode sheets; High-purity zinc foil (99.99%) with a thickness of 100 μm was cut into circular pieces with a diameter of 12 mm. After the zinc foil was wiped clean with alcohol, it was used as the negative electrode of the button cell. Electrolyte membrane number 3-1 is placed between the negative and positive electrode plates. A gasket and spring are then placed on the positive electrode plate, and finally the positive electrode shell is placed on top. The battery is then sealed using a battery sealing machine to obtain a No. 1 button cell Zn || NH4V4O. 10 Full battery.

[0047] Comparative Example 1 The difference from Example 1 is that a conventional aqueous electrolyte is used instead of a solid electrolyte membrane. Specifically, 120 μL of zinc trifluoromethanesulfonate electrolyte (2 mol / L) is added dropwise onto a 16 mm circular glass fiber membrane to assemble a Zn ||NH4V4O 0-type electrolyte. 10 Full battery.

[0048] Example 1 Batteries prepared in Example 1 and Comparative Example 1 were used to investigate their long-cycle performance, rate performance, and self-discharge performance. The results are shown below.

[0049] Figure 1 The long-cycle performance of the solid-state zinc-vanadium battery prepared in Example 1. From... Figure 1 It can be seen from this that: Zn 1 || NH4V4O 10 A full battery can be produced at 0.2 A g. -1 It exhibits cycling stability exceeding 800 cycles at low current densities, and still maintains a 420 mAh g⁻¹ even in the later stages of cycling. -1 Specific capacity. Figure 2 To demonstrate the long-cycle performance of the zinc-vanadium battery prepared in Comparative Example 1. From Figure 2 It can be seen from this that Zn 0 || NH4V4O 10 After approximately 200 cycles, the specific capacity of the full battery has decreased to 200 mAh g. -1 The battery quickly failed, a stark contrast to the high stability of Example 1. From Figure 1 and Figure 2 The comparison shows that the solid electrolyte membrane prepared in the embodiments of this application can provide sufficient hydrogen bond sites for water molecules, confining them to a strong hydrogen bond network, realizing the conversion of free water into bound water, and avoiding the O2 between water molecules and the vanadium layer. 2- The structural collapse caused by hydrogen bonding in the crystal lattice improves the problem of easy dissolution of vanadium cathode under low current, which is of great significance for improving the cycle stability of zinc-vanadium batteries under low current.

[0050] Figure 3 The rate performance of the solid-state zinc-vanadium battery prepared in Example 1 is shown. Figure 3It can be seen that at 0.1 Ag -1 0.2 Ag -1 0.5 A g -1 1 A g -1 2 A g -1 At different current densities, the reversible capacity of the solid-state zinc-vanadium battery is approximately 460 mAh g. -1 440 mAh g -1 400 mAh g -1 360 mAh g -1 300 mAh g -1 When the current density recovers to 0.1 A g -1 At that time, the capacity can recover to approximately 480 mAh g. -1 And it remains stable, indicating that NH4V4O 10 The positive electrode exhibits excellent rate performance and structural stability in solid electrolytes. Figure 4 The rate performance of the zinc-vanadium battery prepared in Comparative Example 1 is shown. Figure 4 It can be seen that the reversible capacity of the zinc-vanadium battery in Comparative Example 1 is significantly lower, especially when the current density recovers to 0.1 A g. -1 When the capacity cannot be restored to the initial capacity, it indicates that its rate performance and reversibility are far inferior to those of solid electrolyte systems.

[0051] The self-discharge suppression capability of the full cells assembled in Example 1 and Comparative Example 1 was evaluated after a 100-hour resting period in a fully charged state. Figure 5 The self-discharge performance of the solid zinc-vanadium battery prepared in Example 1 is shown. Figure 5 It can be seen that the voltage drop of the solid-state zinc-vanadium battery is approximately 0.26 V, and the reversible discharge capacity is 361.55 mAh g. -1 It has a high coulombic efficiency (CE) of 95.9%, which significantly improves the battery's resistance to self-discharge. Figure 6 The self-discharge performance of the zinc-vanadium battery prepared in Comparative Example 1 is shown. Figure 6 It can be seen that the zinc-vanadium battery in Comparative Example 1 has a voltage drop of 0.31 V and a discharge capacity of 234.95 mAh g. -1 The CE ratio was low, at 56.8%. This phenomenon can be attributed to the NH4V4O prepared in Comparative Example 1. 10 The full cell exhibited poor self-discharge performance in 2 M Zn(OTF)2 electrolyte due to complex interfacial side reactions (such as zinc dendrite growth and vanadium dissolution) during storage, which contrasts sharply with the high self-discharge resistance shown in Example 1.

[0052] Figure 7 Zn || NH4V4O assembled for Example 1 10The full cell and various zinc-vanadium battery systems reported in the literature were compared at 0.2 A g. -1 Comparison of long-cycle performance at current densities. From Figure 7 It can be seen that the solid Zn || NH4V4O assembled in Example 1 10 The battery exhibits significant performance advantages at low current densities. In terms of specific capacity, Example 1 shows a capacity of approximately 420 mAh g after 800 cycles. -1 The concentration was significantly higher than that of systems reported in other literature; in terms of long-term cycling stability, Example 1 still maintained approximately 420 mAh g⁻¹ after 800 cycles. -1 The specific capacity of the NH4V4O3 system described in Example 1 is significantly higher than that of other systems in the literature, while the cycle life of other systems only reaches a maximum of 300 cycles, which is insufficient to support long-term stability assessment. The above comparative results fully demonstrate that the NH4V4O3 system described in Example 1 has a superior specific capacity. 10 The synergistic effect of the cathode material and the solid electrolyte effectively suppresses the dissolution problem of vanadium-based cathodes at low current densities, thereby significantly improving the cycle stability of zinc-vanadium batteries and solving the technical problem of easy structural failure of vanadium-based cathode materials at low current densities in the prior art.

[0053] Example 2: Zn || NH4V4O 10 0.2mV s of full battery -1 Cyclic voltammetry test Zn || NH4V4O in Example 1 10 The full cell is at 0.2 mV s -1 The cyclic voltammetry (CV) curve is as follows Figure 8 As shown, Zn || NH4V4O in Comparative Example 1 10 The full cell is at 0.2 mV s -1 The CV curve is as follows Figure 9 As shown.

[0054] Depend on Figure 8 and Figure 9It can be seen that the CV curve of Example 1, which uses a solid electrolyte, shows no abnormal current peaks or curve distortion in the high voltage range of 1.2~1.5 V, indicating that the solid electrolyte can effectively passivate the electrode / electrolyte interface, significantly suppress the occurrence of side reactions such as electrolyte decomposition and hydrogen evolution in the aqueous system, and reduce irreversible losses inside the battery. In contrast, Comparative Example 1, which uses a 2M Zn(OTF)2 electrolyte, shows obvious abnormal peaks and curve distortion in this voltage range, indirectly confirming that its interface side reactions are more severe. At the same time, the CV curve of Comparative Example 1 shows significant peak position shift and peak intensity decay with the increase of scanning number. This is a direct characterization of vanadium dissolution and loss from the cathode material, which will lead to loss of battery active material and rapid capacity decay. On the contrary, the redox peak position of the CV curve of Example 1 is stable and the peak intensity decays slowly, indicating that the solid electrolyte can suppress vanadium dissolution through interface regulation or complexation, maintain the structural integrity of the cathode material, and thus improve the cycle stability and capacity retention of the battery. The above results indicate that, compared with the traditional 2M Zn(OTF)2 electrolyte, the solid electrolyte of the present invention can effectively suppress side reactions and vanadium dissolution, and significantly improve the Zn || NH4V4O 10 Electrochemical stability and cycling performance of full cells. Example 2 Use a scraper to remove NH4V4O 10 The slurry was uniformly coated onto a 500-mesh stainless steel mesh current collector and vacuum dried at 80 °C for 12 h. The final active material loading on the electrode was controlled at 5.1–5.4 mg / cm³. -2 A positive electrode sheet was obtained, in which the active material loading was 514 mg; A 100 μm thick high-purity zinc foil (99.99%) is cut to serve as the negative electrode sheet. Take a polymer solid electrolyte, place it into a pre-cut silicone mold, flatten it, and then stack the negative electrode, separator, and positive electrode in sequence. Place the stacked cell in an aluminum-plastic film, and perform top and side sealing. After venting, the battery is encapsulated, yielding No. 2 Zn || NH4V4O 10 Soft-pack battery.

[0055] The pouch cell prepared in Example 2 was subjected to cycle testing.

[0056] Figure 10 The cycle performance of the high-capacity zinc-vanadium pouch cell prepared in Example 2 is shown. Figure 10 As can be seen, the pouch cell of Example 2 exhibits excellent cycle performance and coulombic efficiency. Its discharge specific capacity stabilizes at approximately 130 mAh after initial activation, with no significant decay within 100 cycles. Simultaneously, the coulombic efficiency remains stable at nearly 100% throughout the cycle. This indicates that the solid-state electrolyte can effectively suppress side reactions at the electrode interface, reduce irreversible losses within the battery, and significantly improve the efficiency of high-load Zn || NH4V4O10 The cycle stability of pouch batteries provides reliable support for the industrial application of high-performance aqueous zinc-ion pouch batteries.

[0057] In summary, this invention provides a polymer solid-state electrolyte designed to address the technical problem of structural collapse and vanadium dissolution in existing vanadium-based cathode materials at low current densities due to free water molecule erosion, thereby affecting battery cycle stability. This invention addresses the structural failure mechanism of vanadium-based cathodes. The preparation method involves introducing polyethylene glycol (PEG) as a matrix into a traditional aqueous electrolyte and adding nanofillers. The PEG matrix and nanofillers synergistically provide sufficient hydrogen bond sites for water molecules in the system, thereby forming a robust hydrogen bond network within the electrolyte, confining free water molecules within this network and converting them into bound water. Through the synergistic effect of the ether-oxygen bonds of PEG4000 and the hydroxyl groups of nano-SiO2, water molecules are bound into bound water, significantly reducing the free water content and inhibiting side reactions such as hydrogen evolution and vanadium dissolution caused by free water. At the same time, the dense network formed by the flexible chains of PEG4000 and the rigid filler of SiO2 can physically prevent structural collapse, and the coordination and electrostatic effects of the surface charge of SiO2 and the ether-oxygen bonds of PEG4000 on vanadium ensure uniform distribution of vanadium and achieve smooth deposition and reversible exfoliation. In addition, the multiple hydrogen bonds formed by the ether-oxygen bonds of PEG4000 and water molecules, and the hydroxyl groups of SiO2 and PEG / water, not only reconstruct the hydrogen bond network to reduce water activity, but also enhance the mechanical strength and interfacial compatibility of the electrolyte, ultimately ensuring the long-term stability of the electrode interface.

[0058] The above design effectively avoids the O2 between free water molecules and the vanadium-based cathode layer. 2- The crystal lattice forms hydrogen bonds, thus preventing the collapse of the layered structure of the vanadium-based cathode and improving the technical defect of easy dissolution of vanadium-based cathodes at low current densities, making the assembled Zn || NH4V4O 10 The full-cell battery has a longer cycle life, significantly improving the cycle stability and commercial potential of zinc-vanadium batteries.

[0059] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A highly stable solid-state zinc-vanadium battery, characterized in that, This includes positive electrode sheets, solid electrolyte membranes, and negative electrode sheets containing vanadium-based compounds; The solid electrolyte membrane is formed by directly pressing a solid electrolyte; the solid electrolyte is prepared by mixing polyethylene glycol, zinc salt, nanofiller and water.

2. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The polyethylene glycol is selected from at least one of PEG2000, PEG4000, PEG6000, and PEG10000.

3. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The zinc salt is at least one of zinc trifluoromethanesulfonate, zinc sulfate, and zinc perchlorate.

4. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The nanofiller is at least one of SiO2, TiO2, and ZrO2.

5. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The mass ratio of polyethylene glycol, zinc salt, nanofiller and water is (0.5~2):(0.5~1):(1~4):(0.5~2).

6. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The thickness of the solid electrolyte membrane is 50~1000 micrometers.

7. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The vanadium-based compound cathode is obtained by coating a vanadium-based compound onto a current collector.

8. The solid-state zinc-vanadium battery according to claim 7, characterized in that, The vanadium-based compound includes at least one of ammonium vanadate, zinc vanadate, and vanadium pentoxide.

9. The solid-state zinc-vanadium battery according to claim 1, characterized in that, The negative electrode is a zinc foil or zinc sheet with a thickness of 20-100 micrometers.

10. A method for preparing a solid-state zinc-vanadium battery according to any one of claims 1 to 9, characterized in that, include: By stacking vanadium-based compound positive electrode sheets, solid electrolyte membranes, and negative electrode sheets layer by layer, and then pressing them directly into a coin cell or soft-pack cell, the layers are bonded together to form a complete battery device.

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