A zinc metal anode with an in-situ multifunctional organic-inorganic interfacial layer, its preparation method and application

Abstract

The present invention discloses a zinc metal anode with an in-situ multifunctional organic-inorganic interface layer, its preparation method and application, which include the following steps: a) surface pretreatment of the zinc foil; b) preparation of a coating solution; c) coating; d) post-treatment. The present invention realizes the ultra-long cycle life of the battery and significantly reduces the zinc deposition overpotential by in-situ constructing a polyvinyl alcohol layer on the zinc metal surface and introducing zinc sulfonate salt with sulfonate ions and nano-inorganic fillers into the interface layer. The zinc-zinc symmetric battery assembled with the zinc metal anode prepared by the present invention can stably cycle for more than 3000 h under the conditions of 0.25 mA cm-2 and 0.25 mAh cm-2. Matching the zinc metal anode of the present invention with an ammonium vanadate cathode to construct an aqueous zinc-ion battery also shows excellent electrochemical performance with 1000 stable cycles and a capacity retention rate close to 100%.

Description

Technical Field

[0001] The present invention belongs to the field of zinc metal anodes in secondary zinc-based batteries, and particularly relates to a zinc metal anode with an in-situ multifunctional organic-inorganic interface layer, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, in the context of reducing dependence on fossil fuels and increasing demand for clean energy, the development of cost-effective energy storage systems has become a promising field. Aqueous rechargeable zinc-based batteries have attracted much attention from researchers due to their non-toxic, safe, and low-cost advantages. Among them, zinc metal batteries such as zinc-manganese, zinc-air, and zinc-iodine have great competitive advantages due to their high theoretical capacity (5849 mAh cm -2 ), weight capacity (820 mAh g -1 ), and low redox potential (-0.76 V).

[0003] However, the commercialization of zinc-based batteries is restricted by many factors, such as zinc dendrites, side reactions, hydrogen evolution reactions, etc. During the cycling process, the nucleation sites on the surface of the zinc anode are limited, and the uneven electric field distribution leads to uneven zinc deposition. Moreover, the tip effect will exacerbate the uneven zinc deposition, resulting in zinc dendrites. The dendrites grow continuously and eventually pierce the separator, causing an internal short circuit of the battery. At the same time, once the brittle zinc dendrites break, they become "dead zinc" and no longer participate in the subsequent charge and discharge processes, resulting in the loss of active substances. In addition, different from lithium batteries, a solid electrolyte interface layer cannot be formed on the surface of the zinc anode during the cycling process. The direct contact between zinc and the electrolyte will cause hydrogen evolution reactions and side reactions. The by-products accumulate on the surface of the anode, covering the active sites, and the generated hydrogen causes the internal pressure of the battery to increase, ultimately leading to the explosion and failure of the battery.

[0004] In response to the above problems, a variety of solutions have been reported, such as anode structure design, zinc-electrolyte interface modification, regulation of electrolyte composition, separator modification, introduction of gel electrolytes, etc. The above methods can effectively improve the performance of the zinc anode, but at the same time, they each have limitations. By designing the structure to increase the electrochemically active area of the zinc anode, thereby reducing the local current density and realizing the uniform distribution of zinc ions on the surface of the anode. However, at the same time, the three-dimensional structure will also increase the contact between the electrolyte and zinc metal, resulting in increased hydrogen evolution, corrosion, and reduced Coulomb efficiency. Electrolyte modification is a method to optimize zinc-based batteries by adjusting the electrolyte system and optimizing the composition. However, the dosage requirements of additives will bring high-cost problems, and some electrolytes have problems of high electrolyte viscosity and low ionic conductivity. The gel electrolyte strategy for separator modification can effectively inhibit dendrite formation, reduce side reactions, and inhibit hydrogen evolution. However, the poor fluidity of the gel results in a "point contact" state between the electrolyte and the electrode, thereby causing the rough surface of the electrode to not be able to fully contact with the gel electrolyte during the cycling process.

[0005] Therefore, a method for comprehensively modifying zinc anodes is needed. Summary of the Invention

[0006] Aiming at the deficiencies in the existing technologies of zinc-based batteries, the purpose of the present invention is to provide a zinc metal anode with an in-situ multifunctional organic-inorganic interface layer, its preparation method and application, so as to achieve the ultra-long cycle life of the battery, significantly reduce the zinc deposition overpotential, and comprehensively modify the zinc anode.

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

[0008] The preparation method of the zinc metal anode with an in-situ multifunctional organic-inorganic interface layer provided by the present invention includes the following steps:

[0009] a) Surface pretreatment of zinc foil: Remove the impurities on the surface of the zinc foil to obtain the pretreated zinc foil;

[0010] b) Preparation of the coating solution: Dissolve polyvinyl alcohol (PVA) in a solvent, then add zinc sulfonate, fully dissolve it, and then add nano-inorganic fillers and disperse them evenly to obtain a PVA mixed coating solution;

[0011] c) Coating: Uniformly coat the PVA mixed coating solution prepared in step b) on the surface of the zinc foil pretreated in step a) to obtain a zinc foil with a surface coating;

[0012] d) Post-treatment: Perform post-treatment on the zinc foil with a surface coating obtained in step c) to obtain a zinc metal anode with an in-situ multifunctional organic-inorganic interface layer.

[0013] Preferably, in step a), the pretreatment method is: Place the zinc foil in alcohol and ultrasonically clean it to remove the impurities on the surface of the zinc foil.

[0014] In step b), the average molecular weight of polyvinyl alcohol is 50,000 - 100,000.

[0015] In step b), the solvent is deionized water.

[0016] In step b), the zinc sulfonate is a zinc sulfonate with a high ionic conductivity, including but not limited to zinc trifluoromethanesulfonate, zinc benzenesulfonate, zinc phenolsulfonate, zinc 4-hydroxybenzenesulfonate, zinc dodecylbenzenesulfonate, zinc bis(trifluoromethanesulfonyl)imide.

[0017] Further preferably, in step b), zinc trifluoromethanesulfonate is selected as the zinc sulfonate.

[0018] In step b), the nano-inorganic filler has the characteristic of high dielectric constant, and the particle size is in the nanometer order of 1 - 900 nm. The nano-inorganic filler is any one of silicon nitride, barium titanate, and barium strontium titanate.

[0019] Further preferably, in the step b), the nano-inorganic filler is selected as nano-amorphous silicon nitride.

[0020] In the step b), the mass percentage of PVA to the solvent is 4-6 wt%, the mass percentage of zinc sulfonate to the solvent is 18-20 wt%, and the mass percentage of nano-inorganic filler to the solvent is 2-3 wt%.

[0021] In the step c), the uniform coating method is scraping with a coater wire bar or a scraper.

[0022] In the step d), the post-treatment method is one or more of the repeated freeze-thaw method, the atmospheric pressure oven drying method, and the freeze-drying method.

[0023] Further preferably, in the step d), the post-treatment is as follows: first, perform repeated freeze-thaw, and then place it in an atmospheric pressure oven for drying to in-situ construct a multifunctional organic-inorganic interface layer on the zinc matrix surface; the specific operation of the repeated freeze-thaw is: first freeze the zinc foil with a surface coating at a low temperature, and then thaw it at room temperature, repeating 1-10 times.

[0024] Further preferably, the specific conditions of the repeated freeze-thaw in the step d) are: the temperature of low-temperature freezing is -20 to -18 °C, the freezing duration is 8-13 h, the thawing temperature is room temperature, and the thawing duration is 1-5 h, repeating 3 times.

[0025] Further preferably, in the step d), the drying temperature is 30-50 °C, and the drying time is 3-7 h.

[0026] In the step d), only part of the moisture in the coating is removed during the baking process, and the prepared interface coating remains in a slightly moist state and has viscosity, so as to better enhance the wettability between the zinc negative electrode and the electrolyte, and keep the interface layer and the zinc matrix in a tightly combined state.

[0027] A zinc metal negative electrode with an in-situ multifunctional organic-inorganic interface layer prepared according to the above preparation method.

[0028] The zinc metal negative electrode with an in-situ multifunctional organic-inorganic interface layer includes a metal zinc matrix and a multifunctional organic-inorganic interface layer covering the surface of the metal zinc matrix.

[0029] The internal structure of the multifunctional organic-inorganic interface layer is that zinc sulfonate and nano-inorganic filler are uniformly distributed in PVA.

[0030] The application of the zinc metal negative electrode with an in-situ multifunctional organic-inorganic interface layer in a zinc-ion battery.

[0031] The present invention uses the repeated freeze-thaw method to in-situ construct a layer of PVA on the zinc metal surface, and at the same time introduces zinc sulfonate salt with high ionic conductivity and nano-inorganic filler material with high dielectric constant characteristics into the PVA. The side chain of PVA contains a large number of hydrophilic groups, hydroxyl groups, to achieve good wettability between the interface layer and the electrolyte; zinc sulfonate salt can provide a fast migration channel for zinc ions; nano-inorganic filler can effectively improve the mechanical properties of the PVA layer, and its high dielectric constant characteristics can induce the formation of a Maxwell polarization electric field in the interface layer, thereby guiding the migration of zinc ions. The synergistic ion conduction and in-situ construction of a hydrophilic layer effectively guide the rapid migration and uniform deposition of zinc ions, resulting in an ultra-long cycle life, while enhancing the wettability between the zinc negative electrode and the electrolyte, inhibiting corrosion, and significantly reducing the zinc deposition overpotential.

[0032] Principle of the present invention:

[0033] 1. In-situ constructing a multifunctional organic-inorganic interface protection layer on the zinc negative electrode can physically effectively prevent the electrolyte from contacting the zinc negative electrode, inhibit side reactions and hydrogen evolution reactions, prevent the corrosion of zinc metal by the electrolyte, and improve the cycle stability of the battery.

[0034] 2. In the present invention, through the repeated freeze-thaw technology, PVA is in-situ polymerized on the zinc electrode sheet, which can not only significantly enhance the strength of PVA, but also significantly enhance the bonding degree between the interface layer and the zinc matrix interface. In addition, the excellent hydrophilic characteristics of PVA can effectively improve the wetting degree between the zinc negative electrode and the electrolyte.

[0035] 3. The zinc salt with high ionic conductivity in the interface layer of the present invention, its sulfonate group can coordinate with zinc ions, reduce the desolvation barrier of zinc ions, thereby promoting the transmission of zinc ions, while significantly reducing the zinc deposition overpotential, and at the same time guiding the uniform deposition of zinc, effectively inhibiting the formation of zinc dendrites, and improving the cycle life and reversibility.

[0036] 4. The doped nano-inorganic filler in the interface layer of the present invention has the advantage of high dielectric constant, which can inhibit the appearance of the space charge field, thereby inhibiting the generation of dendrites. In the electrostatic field, it can undergo dielectric polarization to form electric dipoles in a specific direction, forming a zinc ion migration channel, thereby guiding the transmission of zinc ions in the interface layer. Beneficial effects of the present invention:

[0037] The present invention uses the repeated freeze-thaw method to in-situ construct a layer of polyvinyl alcohol on the zinc metal surface, and at the same time introduces zinc sulfonate salt with high ionic conductivity and nano-inorganic filler material with high dielectric constant characteristics into the PVA, which not only improves the cycle life and stability of the battery, but also significantly reduces the zinc deposition overpotential, effectively inhibiting the formation of zinc dendrites. In particular, the zinc-zinc symmetric battery assembled with the PVA-Zn(CF3SO3)2-Si3N4@Zn zinc metal negative electrode prepared by the present invention at 0.25 mA cm -2 ,0.25 mAh cm-2 Under this condition, it can be stably cycled for more than 3000 h. Finally, the modified zinc metal anode is matched with an ammonium vanadate (NH4V4O 10 ) cathode to construct an aqueous zinc-ion battery, which also shows excellent electrochemical performance with 1000 stable cycles and a capacity retention rate close to 100%. The present invention provides a method for comprehensively modifying zinc anodes. Description of the Drawings

[0038] Figure 1 Scanning electron microscope images of Comparative Example 1 and Example 1: a is the scanning electron microscope image of the pretreated commercial zinc foil used in Comparative Example 1; b is the scanning electron microscope image of the zinc metal anode with an interfacial protective layer prepared in Example 1 of the present invention; c is the cross-sectional scanning electron microscope image and element distribution map of Example 1.

[0039] Figure 2 It is the Fourier transform infrared spectroscopy (FT-IR) image of the PVA-Zn(CF3SO3)2-Si3N4 interfacial layer prepared in Example 1.

[0040] Figure 3 It is the contact angle test images of Comparative Example 1 and Example 1.

[0041] Figure 4 Cycling performance graphs of symmetric cells composed of zinc anodes of Comparative Examples 1-3 and Example 2 and SEM images of the electrodes after cycling: a is the cycling performance graph of zinc-zinc symmetric cells assembled with zinc anodes in Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example 2; b is the SEM image of the electrode after cycling in Comparative Example 1; c is the SEM image of the electrode after cycling in Example 2.

[0042] Figure 5 It is the cycling performance graph of a zinc-ammonium vanadate battery assembled with the materials of Example 3 under 5Ag -1 condition. Detailed Embodiments

[0043] The polyvinyl alcohol used in the following examples is polyvinyl alcohol type 1799, with a degree of alcoholysis of 98% - 99% and an average molecular weight of 74885.

[0044] Example 1

[0045] Preparation of zinc metal electrode with a multifunctional protective layer (PVA-Zn(CF3SO3)2-Si3N4@Zn, hereinafter simply referred to as PZS-Zn): Add 0.25 g of polyvinyl alcohol to 5 mL of deionized water, stir at 95 °C for 1 h until it is completely dissolved, then let the solution cool at room temperature for 24 h. Add 0.96 g of zinc trifluoromethanesulfonate (Zn(CF3SO3)2) to the mixture and stir at room temperature for 3 h to obtain a homogeneous mixed solution. Then add 0.125 g of silicon nitride (Si3N4), stir for 1 h, and then place it in an ultrasonic cleaner and ultrasonicate for 30 min to uniformly disperse Si3N4 in the mixed solution, obtaining a PVA-Zn(CF3SO3)2-Si3N4 mixed solution. At the same time, place a flat commercial zinc foil in alcohol and ultrasonicate for 30 min to remove surface impurities such as grease and dust, obtaining a pretreated zinc foil. Then, use a simple doctor blade method to scrape the prepared PVA-Zn(CF3SO3)2-Si3N4 mixed solution onto the surface of the pretreated zinc foil to obtain a zinc metal negative electrode covered with the solution. Subsequently, use a repeated freeze-thaw technique to in-situ construct a composite interface layer on the zinc foil surface. Specifically, first freeze the zinc metal negative electrode covered with the solution at -18 °C for 10 h, then take it out and thaw at room temperature for 3 h, repeat the freeze-thaw step 3 times, and then dry it in an oven at 50 °C for 3 h. Finally, a zinc metal negative electrode with a multifunctional organic-inorganic interface protective layer (PVA-Zn(CF3SO3)2-Si3N4@Zn) is obtained.

[0046] The PVA-Zn(CF3SO3)2-Si3N4@Zn prepared in this example was tested, and its scanning electron microscope image is as shown in Figure 1 Figure [Figure number not provided in the original]. The Fourier transform infrared spectroscopy test results of the PVA-Zn(CF3SO3)2-Si3N4 interface layer are as shown in Figure 2 Figure [Figure number not provided in the original], and the contact angle test results with the electrolyte are as shown in Figure 3 b in [Figure number not provided in the original]. As can be seen from Figure 1 Figure [Figure number not provided in the original], the surface of the interface layer is flat, with a thickness of about 20 μm, and the elements C, N, Si, O, and F are evenly distributed in the interface layer. Figure 2 In [Figure number not provided in the original], the stretching vibration peak corresponding to -OH is at 3444 cm -1 , the stretching vibration peak corresponding to C-H is at 2930 cm -1 , the absorption peaks at 1244 cm -1 and 1026 cm -1 are related to -SO3 - , the peak at 1639 cm -1 corresponds to -OH, and the peak at 1420 cm -1 corresponds to C-O-H, proving that the multifunctional organic-inorganic interface protective layer PVA-Zn(CF3SO3)2-Si3N4 was successfully prepared. As can be seen from Figure 3It can be seen that the contact angle between the PVA-Zn(CF3SO3)2-Si3N4 interfacial layer and the electrolyte is only 30.6°, showing hydrophilic characteristics, which can improve the wettability between the zinc anode and the electrolyte and promote the transport of zinc ions.

[0047] Comparative Example 1

[0048] The zinc metal anode is a commercial zinc foil (Bare Zn) only after pretreatment. The test results of the contact angle between it and the electrolyte are as Figure 3 shown in a below.

[0049] Comparative Example 2

[0050] This comparative example is basically the same as Example 1, except that Si3N4 is not added, and the remaining steps are the same as those in Example 1, obtaining a PVA-Zn(CF3SO3)2@Zn zinc metal anode (hereinafter referred to as PZ-Zn for short).

[0051] Comparative Example 3

[0052] This comparative example is basically the same as Example 1, except that Zn(CF3SO3)2 and Si3N4 are not added, and the remaining steps are the same as those in Example 1, obtaining a PVA@Zn zinc metal anode (hereinafter referred to as P-Zn for short).

[0053] Performance Test of Example 2

[0054] In order to test the modification effect of the PVA-Zn(CF3SO3)2-Si3N4 interfacial layer in the zinc battery and its influence on the cycle life. The PZS-Zn zinc metal anode was assembled into a zinc-zinc symmetric battery for testing. Taking PZS-Zn as the positive and negative electrode plates, 2 mol L -1 aqueous zinc sulfate solution as the electrolyte, using stainless steel gaskets with thicknesses of 1 mm and 0.5 mm, spring pieces, and button batteries of model CR2032 for battery assembly, obtaining a Zn-PZS||PZS-Zn symmetric battery. Under the conditions of a current density of 0.25 mA cm -2 and a areal capacity density of 0.25 mAh cm -2 , the test results of its cycle stability are shown in Figure 4 a below. Disassembling the PZS-Zn symmetric battery after 50 cycles, observing the surface morphology of the electrode after cycling with a scanning electron microscope, the test results are as Figure 4 shown in c below.

[0055] Assembling the zinc electrode in Comparative Example 1 into a symmetric battery: using the pretreated zinc foil in Comparative Example 1 as the positive electrode and the counter electrode, 2 mol L -1An aqueous zinc sulfate solution was used as the electrolyte. A Bare Zn||Bare Zn symmetric battery was assembled using stainless steel gaskets with thicknesses of 1 mm and 0.5 mm, spring sheets, and button cells of model CR2032. At a current density of 0.25 mA cm -2 and areal capacity density of 0.25 mAh cm -2 , the test results of its cycling stability are shown in Figure 4 as shown in a. The Bare Zn symmetric battery that had been cycled 50 times was disassembled, and the surface morphology of the electrode after cycling was observed using a scanning electron microscope. The test results are as shown in Figure 4 as shown in b.

[0056] The PZ-Zn electrode in Comparative Example 2 was assembled into a symmetric battery: The zinc negative electrode (PZ-Zn) prepared in Comparative Example 2 was used as the positive electrode and counter electrode, and 2 mol L -1 aqueous zinc sulfate solution was used as the electrolyte. A Zn-PZ||PZ-Zn symmetric battery was assembled using stainless steel gaskets with thicknesses of 1 mm and 0.5 mm, spring sheets, and button cells of model CR2032. At a current density of 0.25 mA cm -2 and areal capacity density of 0.25 mAh cm -2 , the test results of its cycling stability are shown in Figure 4 as shown in a.

[0057] The P-Zn electrode in Comparative Example 3 was assembled into a symmetric battery: The zinc negative electrode (P-Zn) prepared in Comparative Example 3 was used as the positive electrode and counter electrode, and 2 mol L -1 aqueous zinc sulfate solution was used as the electrolyte. A Zn-P||P-Zn symmetric battery was assembled using stainless steel gaskets with thicknesses of 1 mm and 0.5 mm, spring sheets, and button cells of model CR2032. At a current density of 0.25 mA cm -2 and areal capacity density of 0.25 mAh cm -2 , the test results of its cycling stability are shown in Figure 4 as shown in a.

[0058] As can be seen from Figure 4 a, at 0.25 mA cm -2 and 0.25 mAh cm -2Under the condition that, in Comparative Example 1, only the pre-treated zinc electrode could be stably cycled for 80 h, and then the battery short-circuited. In Comparative Example 3, the P-Zn electrode could be stably cycled for 530 h. In Comparative Example 2, the PZ-Zn electrode could be stably cycled for 1200 h. The zinc-zinc symmetric battery assembled with the PZS-Zn zinc metal anode in Example 1 could be stably cycled for more than 3000 h. It shows that both PVA and the introduced Zn(CF3SO3)2 and Si3N4 can effectively extend the service life of the electrode. Moreover, the zinc metal anode (PZS-Zn) with the PVA-Zn(CF3SO3)2-Si3N4 interface layer has the best performance and can be stably cycled for more than 1500 cycles under the condition of 0.25 mA cm -2 , 0.25 mAh cm -2 .

[0059] To explore the inhibition effect of the PZS interface layer on zinc dendrites, the symmetric batteries of Comparative Example 1 and Example 1 were disassembled after 50 cycles, and the diaphragm and the residual zinc sulfate in the electrolyte attached to the surface of the electrode after cycling were washed away by means of ultrasonic and alcohol rinsing. Then, the surface morphology of the electrode was observed by scanning electron microscopy. The results are as shown in Figure 4 b and c. It can be observed that uneven deposition occurred during the cycling of the bare zinc anode without a protective layer. There were a large number of diaphragm fibers on the surface of the electrode, and "dead zinc" and by-products were generated. However, for the zinc metal anode protected by the PZS interface layer, during the charge and discharge process, zinc was evenly deposited on the surface of the electrode, and the surface of the electrode was still smooth and uniform after cycling.

[0060] Example 3

[0061] The zinc metal anode (PZS-Zn) of Example 1 was combined with the ammonium vanadate (NH4V4O 10 ) cathode coated on a stainless steel mesh to form a button zinc-ion battery. The electrolyte used was an aqueous solution of zinc sulfate with a concentration of 2 mol L -1 . At the same time, stainless steel gaskets with thicknesses of 1 mm and 0.5 mm, spring sheets, and button batteries of model CR2032 were used to complete the assembly. The button zinc-ion capacitor assembled in this example was tested under the condition of a current density of 1 A g -1 . The cycle number and capacity are as shown in Figure 5 . The PZS-Zn||NH4V4O 10 zinc-ion battery has excellent cycle performance and can still have a capacity retention rate of nearly 100% after 1000 cycles ( Figure 5 ). However, the capacity retention rate of the button zinc-ion capacitor formed by matching the bare zinc anode of Comparative Example 1 with the ammonium vanadate cathode dropped to 25.7% after 1000 cycles.

[0062] Example 4

[0063] 0.2 g of polyvinyl alcohol was added to 5 mL of deionized water, and stirred at 95 °C for 1 h until it was completely dissolved. Subsequently, the solution was placed at room temperature and cooled for 24 h. 0.9 g of zinc trifluoromethanesulfonate was added to the mixture, and stirred at room temperature for 3 h to obtain a homogeneous mixed solution. Then, 0.1 g of silicon nitride was added, stirred for 1 h, and then sonicated in an ultrasonic cleaner for 30 min to uniformly disperse Si3N4 in the mixed solution, obtaining a PVA-Zn(CF3SO3)2-Si3N4 mixed solution. The remaining steps were the same as those in Example 1, and finally a zinc metal negative electrode with an interfacial protective layer (PVA-Zn(CF3SO3)2-Si3N4@Zn) was obtained.

[0064] Example 5

[0065] 0.3 g of polyvinyl alcohol was added to 5 mL of deionized water, and stirred at 95 °C for 1 h until it was completely dissolved. Subsequently, the solution was placed at room temperature and cooled for 24 h. 1.0 g of zinc trifluoromethanesulfonate was added to the mixture, and stirred at room temperature for 3 h to obtain a homogeneous mixed solution. Then, 0.2 g of silicon nitride was added, stirred for 1 h, and then sonicated in an ultrasonic cleaner for 30 min to uniformly disperse Si3N4 in the mixed solution, obtaining a PVA-Zn(CF3SO3)2-Si3N4 mixed solution. The remaining steps were the same as those in Example 1, and finally a zinc metal negative electrode with an interfacial protective layer (PVA-Zn(CF3SO3)2-Si3N4@Zn) was obtained.

[0066] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, the improvements and breakthroughs obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a zinc metal anode with an in-situ multifunctional organic-inorganic interface layer, comprising the following steps: a) Surface pretreatment of zinc foil: Remove impurities on the surface of the zinc foil to obtain pretreated zinc foil; b) Preparation of coating solution: Dissolve polyvinyl alcohol in a solvent, then add zinc sulfonate salt, fully dissolve, and then add nano-inorganic filler, and disperse evenly to obtain a polyvinyl alcohol mixed coating solution; c) Coating: Uniformly coat the polyvinyl alcohol mixed coating solution prepared in step b) on the surface of the pretreated zinc foil in step a) to obtain a zinc foil with a surface coating; d) Post-treatment: Perform post-treatment on the zinc foil with a surface coating obtained in step c) to obtain a zinc metal anode with an in-situ multifunctional organic-inorganic interface layer; In step b), the zinc sulfonate salt is any one of zinc trifluoromethanesulfonate, zinc benzenesulfonate, zinc phenolsulfonate, zinc 4-hydroxyphenolsulfonate, and zinc dodecylbenzenesulfonate; the nano-inorganic filler is any one of nano-amorphous silicon nitride, barium titanate, and barium strontium titanate.

2. The preparation method according to claim 1, characterized in that, In step b), the average molecular weight of polyvinyl alcohol is 50,000 - 100,000; the solvent is deionized water.

3. The preparation method according to claim 2, characterized in that, In step b), zinc trifluoromethanesulfonate is selected as the zinc sulfonate salt, and nano-amorphous silicon nitride is selected as the nano-inorganic filler.

4. The preparation method according to claim 1, wherein In step b), the mass percentage of polyvinyl alcohol to the solvent is 4 - 6 wt%, the mass percentage of zinc sulfonate salt to the solvent is 18 - 20 wt%, and the mass percentage of nano-inorganic filler to the solvent is 2 - 3 wt%.

5. The preparation method according to claim 1, wherein In step c), the method of uniform coating is to scrape with a coater wire bar or a scraper.

6. The preparation method according to claim 1, characterized in that, In step d), the post-treatment method is one or more of the repeated freeze-thaw method, the normal pressure oven drying method, and the freeze-drying method.

7. The preparation method according to claim 6, characterized in that, In step d), the post-treatment is: first perform repeated freeze-thaw, and then place it in a normal pressure oven for drying to in-situ construct a multifunctional organic-inorganic interface layer on the surface of the zinc matrix; the specific operation of the repeated freeze-thaw is: first freeze the zinc foil with a surface coating at a low temperature, and then thaw it at room temperature, repeating 1 - 10 times.

8. The preparation method according to claim 7, characterized in that, In step d), the specific experimental conditions of the repeated freeze-thaw are: the temperature of low-temperature freezing is -20~ -18 °C, the freezing duration is 8 - 13 h, the thawing temperature is room temperature, the thawing duration is 1 - 5 h, and it is repeated 3 times; the temperature of normal pressure oven drying is 30~50 °C, and the drying time is 3 - 7 h.

9. A zinc metal anode with an in-situ multifunctional organic-inorganic interface layer prepared by the preparation method according to any one of claims 1~8.

10. An application of the zinc metal anode with an in-situ multifunctional organic-inorganic interface layer according to claim 9 in a zinc-ion battery.

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