A method for stabilizing the zinc anode of an aqueous zinc-ion battery

Abstract

This invention discloses a method for stabilizing the zinc anode of an aqueous zinc-ion battery, belonging to the field of aqueous zinc-ion battery technology. The invention involves coating a zinc sheet with dipentaerythritol (DPE) to form a coating with a thickness of 10–30 μm. This coating serves as the anode of the aqueous zinc-ion battery. During battery cycling, the DPE layer continuously functions to induce and controllably grow basic zinc sulfate (ZHS). Furthermore, a uniform ZHS layer regularly arranges itself between the DPE and Zn layers, forming a tight solid electrolyte interface (SEI), ultimately creating an organic / inorganic dual-interface layer (DPE / ZHS@Zn). This dual-interface layer not only effectively inhibits dendrite growth but also improves the interfacial stability of the zinc anode, providing new theoretical guidance for zinc anode modification. This approach is expected to fundamentally solve the stability problem of zinc anodes and promote the commercialization of aqueous zinc-ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc-ion battery technology, and particularly relates to a method for stabilizing the zinc anode of an aqueous zinc-ion battery. Background Technology

[0002] Aqueous zinc-ion batteries (AZIBs) are considered a highly promising large-scale energy storage technology due to their advantages such as low cost, high safety, and high volumetric energy density. However, the stability of the zinc metal anode has been a key bottleneck restricting its commercial application. In aqueous electrolytes, the zinc anode is prone to hydrogen evolution reaction (HER) during charge and discharge, leading to the formation of byproducts such as basic zinc sulfate (ZHS). These byproducts disrupt the uniformity of electron and ion distribution at the zinc anode interface, thereby inducing dendrite growth and ultimately causing problems such as short circuits and shortened cycle life.

[0003] To address the stability issues of zinc anodes, researchers have explored various methods, including surface modification, structural optimization, electrolyte engineering, and membrane design. For example, coating the zinc anode surface with a protective film or using a three-dimensional current collector as a pre-deposited zinc substrate can effectively suppress dendrite growth. Furthermore, optimizing the electrolyte composition, such as introducing high-concentration salt electrolytes (WISEs) or hydrated eutectic electrolytes (HEEs), can broaden the electrochemical stability window of the electrolyte and suppress side reactions. However, while these methods have made some progress, they have not fundamentally solved the problem of basic zinc sulfate byproduct formation. Meanwhile, due to its high ionic conductivity and low electronic conductivity, zinc sulfate (ZHS) is an ideal candidate material for stabilizing the zinc anode interface. Therefore, controlling the controlled growth of ZHS to form a uniform and dense ZHS layer on the zinc anode would be a way to turn a potential problem into a benefit.

[0004] Currently, the formation of a dense ZHS layer on the zinc anode surface is mainly achieved through electrolyte additives. However, electrolyte additives often increase battery polarization and affect charge / discharge efficiency. Furthermore, the zinc anode surface is prone to chemical corrosion during battery charging and discharging. Therefore, controlling ZHS growth while avoiding the negative effects of electrolyte additives remains a significant challenge. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for stabilizing the zinc anode of an aqueous zinc-ion battery.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for stabilizing the zinc anode of an aqueous zinc-ion battery, wherein dipentaerythritol (DPE) is coated onto the surface of a zinc sheet to form a coating with a thickness of 10–30 μm, which is then used as the anode of the aqueous zinc-ion battery.

[0008] The structural formula of dipentaerythritol is:

[0009] This invention involves coating a zinc sheet with dipentaerythritol (DPE) to form a coating, which is then used as the negative electrode in an aqueous zinc-ion battery. During cycling, the DPE layer continuously functions to induce and controllably grow basic zinc sulfate (ZHS). Furthermore, a uniform ZHS layer regularly arranges itself between the DPE and Zn layers, forming a tight solid electrolyte interface (SEI), ultimately creating an organic / inorganic dual-interface layer (DPE / ZHS@Zn). This dual-interface layer not only effectively inhibits dendrite growth but also improves the interfacial stability of the zinc negative electrode, providing novel theoretical guidance for zinc negative electrode modification. This approach holds promise for fundamentally solving the stability problem of zinc negative electrodes and advancing the commercialization of aqueous zinc-ion batteries.

[0010] Furthermore, the method for stabilizing the zinc anode of an aqueous zinc-ion battery includes the following steps:

[0011] First, DPE and polyvinylidene fluoride (PVDF) are mixed, then N-methylpyrrolidone (NMP) is added and mixed evenly to obtain a slurry;

[0012] The slurry is coated onto the surface of a zinc sheet and dried to obtain an aqueous coated electrode (DPE@Zn);

[0013] The coated electrode of the water system is used as the negative electrode to assemble an aqueous zinc-ion battery.

[0014] Furthermore, the mass ratio of dipentaerythritol to polyvinylidene fluoride is (7-9):(1-3). For example, the mass ratio of dipentaerythritol to polyvinylidene fluoride is 7:3, 8:2, or 9:1, preferably 9:1.

[0015] Furthermore, before coating the zinc sheet with the slurry, the zinc sheet is pretreated: one side of the zinc sheet is sanded smooth with sandpaper, then rinsed with water and anhydrous ethanol in sequence, and dried.

[0016] For example, before coating the zinc sheet with the slurry, the zinc sheet is pretreated as follows: select a zinc sheet with a thickness of 0.05 mm, polish one side of the zinc sheet with 2000 grit sandpaper, rinse it three times with deionized water, rinse it three times with ethanol, and dry it for later use. The purpose of the above treatment is to remove the oxide layer and surface impurities generated on the zinc sheet in the air.

[0017] For example, the coating thickness is 10 μm, 15 μm, 20 μm, 25 μm or 30 μm.

[0018] When the coated electrode of the water system is used as the negative electrode to assemble an aqueous zinc-ion battery, the battery type can be either a symmetrical battery or an asymmetrical battery.

[0019] For example, when assembling a symmetrical battery, the assembly steps are as follows: DPE@Zn is cut into electrode sheets with a diameter of 12 mm using a slicer. One electrode sheet is placed in the negative electrode shell, ensuring that the coated side contacts the glass fiber separator. Then, the glass fiber separator is placed in, and 100 μL of a 2 mol / L zinc sulfate solution is added as the electrolyte to completely wet the glass fiber separator. Another electrode sheet is then placed on top of the glass fiber separator as the zinc negative electrode sheet, again ensuring that the coated side contacts the glass fiber separator. Next, a spacer and a spring are placed in place. Finally, the positive electrode shell is attached, and the battery is sealed using a battery packaging machine. This yields a modified zinc negative electrode aqueous zinc-ion symmetrical button cell, labeled as DPE@Zn / / DPE@Zn symmetrical battery.

[0020] Currently, constructing a polyhydroxyl coating on the zinc anode can effectively achieve the desolvation of solvated zinc ions (through hydrogen bonding between hydroxyl groups), thereby avoiding water-induced side reactions. However, since the standard potential of zinc metal is -0.76V, hydrogen evolution reaction cannot be completely avoided, leading to the formation of byproducts (such as basic zinc sulfate, ZHS). ZHS is an ideal material for stabilizing the zinc anode interface. Therefore, if the growth of ZHS can be controlled to form a protective layer in situ, it can be a valuable resource. While in existing technologies, constructing a dense ZHS layer on the zinc anode is mainly achieved through electrolyte additives, these additives often increase battery polarization and affect charge / discharge efficiency. Furthermore, the zinc anode surface is prone to chemical corrosion during battery charging and discharging. To address these issues, this invention pre-coats the zinc anode surface with a dipentaerythritol (DPE) coating, thereby achieving controllable formation and growth of ZHS. First, DPE is a polyhydroxyl compound that can continuously and effectively protect the zinc anode before inducing ZHS formation, preventing corrosion. Secondly, DPE can induce dense horizontal growth of ZHS, forming a protective layer for the zinc anode in situ. Finally, ZHS is also a polyhydroxyl substance, which can further promote the desolvation process. Furthermore, this in-situ formed dynamic protective layer can avoid the problem of DPE coating failure due to volume changes during long-term cycling. The dual-interface layer formed by this strategy can not only effectively suppress dendrite growth but also improve the interfacial stability of the zinc anode, providing new theoretical guidance for the modification of zinc anodes. Through this strategy, it is hoped that the stability problem of zinc anodes can be fundamentally solved, promoting the commercialization of aqueous zinc-ion batteries.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] This invention involves coating a zinc sheet with dipentaerythritol (DPE) to form a coating, which is then used as the negative electrode in an aqueous zinc-ion battery. During the zinc deposition process, the coated DPE layer undergoes hydrolysis, causing pH fluctuations at the zinc negative electrode interface. This induces basic zinc sulfate (ZHS) to stack parallel at the interface, forming a dense protective layer. The formation of ZHS significantly alleviates the side reactions between the zinc negative electrode and water. A uniform ZHS layer is regularly arranged between the DPE and Zn interlayers, forming a tight solid electrolyte interface (SEI), ultimately forming an organic / inorganic dual interface layer (DPE / ZHS@Zn). This organic / inorganic dual interface layer can increase the hydrogen evolution overpotential, effectively mitigating the hydrogen evolution side reaction and protecting the zinc anode. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 In Figure 1, a is a scanning electron microscope (SEM) image of Bare Zn in Comparative Example 1, b is a SEM image of DPE@Zn in Example 1, and c is a SEM image of ZHS@Zn in Example 1.

[0025] Figure 2 In Figure a, X-ray diffraction (XRD) patterns of Bare Zn in Comparative Example 1, DPE@Zn in Example 1, and DPE / ZHS@Zn in Example 1 are shown; in Figure b, SEM image and corresponding energy dispersive spectroscopy (EDS) image of DPE / ZHS@Zn in Example 1 are shown; and in Figure c, the specific content ratio of each element is shown.

[0026] Figure 3 In Figure a, the linear sweep voltammetry (LSV) plots of Bare Zn in Comparative Example 1 and DPE / ZHS@Zn in Example 1 are shown. In Figure b, the LSV plots of Bare Cu and DPE / ZHS@Cu (the preparation method of DPE / ZHS@Cu is the same as that of DPE / ZHS@Zn in Example 1, except that the original zinc sheet is replaced with an equivalent copper sheet) are shown. In Figure c, the LSV plots of Bare Ti and DPE / ZHS@Ti (the preparation method of DPE / ZHS@Ti is the same as that of DPE / ZHS@Zn in Example 1, except that the original zinc sheet is replaced with an equivalent titanium sheet) are shown.

[0027] Figure 4 Tafel curves for Bare Zn in Comparative Example 1 and DPE / ZHS@Zn in Example 1;

[0028] Figure 5 In Figure a, the chronoamperograms of Bare Zn in Comparative Example 1 and DPE / ZHS@Zn in Example 1 are shown; in Figure b, the final optical microscope image of Bare Zn is shown; and in Figure c, the final optical microscope image of DPE / ZHS@Zn is shown.

[0029] Figure 6 Cycling curves for DPE / ZHS@Zn symmetric cells and Bare Zn symmetric cells;

[0030] Figure 7 Cycling curves for DPE / ZHS@Zn||DPE / ZHS@Cu half-cell and Bare Zn||Bare Cu(Zn||Cu) half-cell

[0031] Figure 8 The cycling curves are for the aqueous zinc-ion symmetric button cell in Comparative Example 2. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0036] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0037] Embodiments of the present invention provide a method for stabilizing the zinc anode of an aqueous zinc-ion battery, wherein dipentaerythritol (DPE) is used. A coating is applied to the surface of a zinc sheet to form a coating with a thickness of 10–30 μm, which is then used as the negative electrode of an aqueous zinc-ion battery.

[0038] This invention involves coating a zinc sheet with dipentaerythritol (DPE) to form a coating, which is then used as the negative electrode in an aqueous zinc-ion battery. During cycling, the DPE layer continuously functions to induce and controllably grow basic zinc sulfate (ZHS). Furthermore, a uniform ZHS layer regularly arranges itself between the DPE and Zn layers, forming a tight solid electrolyte interface (SEI), ultimately creating an organic / inorganic dual-interface layer (DPE / ZHS@Zn). This dual-interface layer not only effectively inhibits dendrite growth but also improves the interfacial stability of the zinc negative electrode, providing novel theoretical guidance for zinc negative electrode modification. This approach holds promise for fundamentally solving the stability problem of zinc negative electrodes and advancing the commercialization of aqueous zinc-ion batteries.

[0039] In some embodiments of the present invention, a method for stabilizing the zinc anode of an aqueous zinc-ion battery includes the following steps:

[0040] First, DPE and polyvinylidene fluoride (PVDF) are mixed, then N-methylpyrrolidone (NMP) is added and mixed evenly to obtain a slurry;

[0041] The slurry is coated onto the surface of a zinc sheet and dried to obtain an aqueous coated electrode (DPE@Zn);

[0042] A water-based zinc-ion battery is assembled by using a coated electrode as the negative electrode.

[0043] In some embodiments of the present invention, the mass ratio of dipentaerythritol to polyvinylidene fluoride is (7-9):(1-3). Exemplary examples show that the mass ratio of dipentaerythritol to polyvinylidene fluoride is 7:3, 8:2, or 9:1, preferably 9:1.

[0044] In some embodiments of the present invention, the zinc sheet is pretreated before the slurry is applied to the surface of the zinc sheet: one side of the zinc sheet is sanded smooth with sandpaper, then rinsed with water and anhydrous ethanol in sequence, and dried.

[0045] In some preferred embodiments of the present invention, the zinc sheet is pretreated before the slurry is applied to the zinc sheet surface as follows: a 0.05 mm thick zinc sheet is selected, one side of the zinc sheet is polished smooth with 2000 grit sandpaper, then rinsed with deionized water 3 times, and finally rinsed with ethanol 3 times. After drying, it is ready for use. The purpose of the above treatment is to remove the oxide layer and surface impurities generated on the zinc sheet in the air.

[0046] In some embodiments of the present invention, the coating thickness is 10 μm, 15 μm, 20 μm, 25 μm or 30 μm.

[0047] When an aqueous zinc-ion battery is assembled using a coated electrode as the negative electrode, the battery type can be either a symmetrical battery or an asymmetrical battery.

[0048] In some embodiments of the present invention, the assembly steps for assembling the symmetrical battery are as follows: DPE@Zn is cut into electrode sheets with a diameter of 12 mm using a slicer. One electrode sheet is placed in the negative electrode shell, ensuring that the coated side contacts the glass fiber separator. Then, the glass fiber separator is placed in, and 100 μL of a 2 mol / L zinc sulfate solution is added as the electrolyte to completely wet the glass fiber separator. Another electrode sheet is then placed on top of the glass fiber separator as the zinc negative electrode sheet, again ensuring that the coated side contacts the glass fiber separator. Next, a gasket and a spring are placed in place. Finally, the positive electrode shell is attached, and the battery is sealed using a battery packaging machine, thus obtaining a modified zinc negative electrode aqueous zinc-ion symmetrical button cell, labeled as DPE@Zn / / DPE@Zn symmetrical battery.

[0049] Currently, constructing a polyhydroxyl coating on the zinc anode can effectively achieve the desolvation of solvated zinc ions (through hydrogen bonding between hydroxyl groups), thereby avoiding water-induced side reactions. However, since the standard potential of zinc metal is -0.76V, hydrogen evolution reaction cannot be completely avoided, leading to the formation of byproducts (such as basic zinc sulfate, ZHS). ZHS is an ideal material for stabilizing the zinc anode interface. Therefore, if the growth of ZHS can be controlled to form a protective layer in situ, it can be a way to turn waste into treasure. While in existing technologies, constructing a dense ZHS layer on the zinc anode is mainly achieved through electrolyte additives, these additives often increase battery polarization and affect charge / discharge efficiency. Furthermore, the zinc anode surface is prone to chemical corrosion during battery charging and discharging. To address these issues, this invention pre-coats a dipentaerythritol (DPE) layer on the zinc anode surface, thereby achieving controllable formation and growth of ZHS. First, DPE is a polyhydroxyl compound that is almost insoluble in water, thus providing continuous and effective protection for the zinc anode. Secondly, DPE can prevent zinc anode corrosion before ZHS formation is induced, while avoiding the adverse effects of other electrolyte additives. Finally, ZHS is also a polyhydroxy substance, which can further promote the desolvation process. Furthermore, this in-situ formed dynamic protective layer can prevent DPE coating failure due to volume changes during long-term cycling. The dual-interface layer formed by this strategy not only effectively inhibits dendrite growth but also improves the interfacial stability of the zinc anode, providing new theoretical guidance for zinc anode modification. This strategy holds promise for fundamentally solving the stability problem of zinc anodes and promoting the commercialization of aqueous zinc-ion batteries.

[0050] The principle of this invention is as follows: This invention provides a method for stabilizing aqueous zinc-ion batteries. Compared to lithium-ion batteries, the protection of the negative electrode is based on a completely different concept. Lithium-ion batteries use organic electrolytes, while zinc-ion batteries use aqueous electrolytes. During use, zinc-ion batteries experience water-induced side reactions, such as hydrogen evolution, corrosion, and the generation of the byproduct ZHS. This invention utilizes the principle that DPE has multiple hydroxyl groups, is insoluble in water, and undergoes hydrolysis to induce the formation of a robust ZHS protective layer, ultimately forming an organic / inorganic dual-interface layer. This effectively protects the zinc negative electrode from damage caused by water-induced side reactions, extending the lifespan of the aqueous zinc-ion battery.

[0051] The reagents used in the embodiments and comparative examples of this invention were all purchased commercially available.

[0052] In the embodiments and comparative examples of this invention, dipentaerythritol was purchased from Ron Reagents; polyvinylidene fluoride (PVDF) was purchased from Dongguan Kelude Innovation Technology Co., Ltd.; and glass fiber diaphragm was purchased from Whatman.

[0053] It should be noted that all aspects not described in detail in this invention are conventional operating methods in the field and are not the focus of this invention. For example, the specific method of polishing is completed using conventional methods.

[0054] The technical solution of the present invention will be further illustrated by the following embodiments.

[0055] Example 1

[0056] (1) Zinc sheet pretreatment: Select zinc sheets with a thickness of 0.05 mm, polish one side of the zinc sheet with 2000-grit sandpaper, rinse with deionized water 3 times, and finally rinse with ethanol 3 times. After the above treatment, dry and set aside. The purpose of the above treatment is to remove the oxide layer and surface impurities generated on the zinc sheet in the air.

[0057] (2) Dipentaerythritol (DPE, 100 mg) and polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 9:1. Then, 15 drops of N-methylpyrrolidone (NMP) were added and mixed evenly in an agate mortar to obtain a slurry. The slurry was evenly coated onto the surface of a zinc sheet with a blade to a thickness of 20 μm. The zinc sheet was then removed and placed in a vacuum drying oven and dried at 60 °C for 12 h to prepare a coated electrode (DPE@Zn). The specific structural formula of the organic compound DPE is shown below:

[0058]

[0059] (3) Battery assembly: The DPE@Zn prepared in step (2) is cut into electrode sheets with a diameter of 12 mm using a slicer. One electrode sheet is placed in the negative electrode shell, ensuring that the coated side is in contact with the glass fiber membrane. Then, the glass fiber membrane is placed in, and 100 μL of 2 mol / L zinc sulfate solution is dropped in as the electrolyte to completely wet the glass fiber membrane. Then, another electrode sheet is placed on top of the glass fiber membrane as the zinc negative electrode sheet, again ensuring that the coated side is in contact with the glass fiber membrane. After that, the gasket and spring are placed in, and finally, the positive electrode shell is attached. The battery is then sealed using a battery packaging machine to obtain a modified zinc negative electrode aqueous zinc ion symmetric button cell, labeled as DPE@Zn / / DPE@Zn symmetric cell.

[0060] The DPE@Zn / / DPE@Zn symmetric cell was pre-cycled for 50 hours on a Newway battery tester. During this period, the DPE layer continued to function, enabling the induction and controllable growth of basic zinc sulfate (ZHS). Subsequently, a uniform ZHS layer regularly arranged between the DPE and Zn interlayers to form a tight solid electrolyte interface (SEI), ultimately forming an organic / inorganic dual interface (DPE / ZHS@Zn).

[0061] Example 2

[0062] Same as Example 1, except that the mass ratio of DPE to PVDF in step (2) is 8:2.

[0063] Example 3

[0064] Same as Example 1, except that the mass ratio of DPE to PVDF in step (2) is 7:3.

[0065] Example 4

[0066] Same as Example 1, except that the coating thickness is 10 μm in step (2).

[0067] Example 5

[0068] Same as Example 1, except that the coating thickness is 15 μm in step (2).

[0069] Example 6

[0070] Same as Example 1, except that the coating thickness is 25 μm in step (2).

[0071] Example 7

[0072] Same as Example 1, except that the coating thickness is 30 μm in step (2).

[0073] Comparative Example 1

[0074] Same as Example 1, except that the DPE@Zn electrode sheet is replaced with uncoated Zn (Bare Zn). After assembling the electrode sheet, an unmodified zinc negative electrode aqueous zinc ion symmetric button cell is obtained, labeled as Zn / / Zn symmetric cell.

[0075] Comparative Example 2

[0076] (1) Zinc sheet pretreatment: Same as in Example 1;

[0077] (2) Mix DPE (100mg) and PVDF at a mass ratio of 9:1, then add 15 drops of NMP and mix evenly in an agate mortar to obtain a slurry. Coat the slurry evenly on the glass fiber membrane with a blade. The coating thickness is 20μm. Place it in a vacuum drying oven and dry at 60℃ for 12h to obtain the treated glass fiber membrane.

[0078] (3) Battery assembly: Cut the pretreated zinc sheet into electrode sheets with a diameter of 12 mm using a slicer. Place one electrode sheet into the negative electrode shell, then place the treated glass fiber membrane in it, and drop 100 μL of 2 mol / L zinc sulfate solution as the electrolyte to completely wet the glass fiber membrane. Then place another electrode sheet on top of the glass fiber membrane as the zinc negative electrode sheet, then place the gasket and spring sheet in it, and finally put the positive electrode shell on. Use a battery packaging machine to seal the battery to obtain an aqueous zinc-ion symmetric button cell.

[0079] In this comparative example, treating the separator with DPE did not yield the same effect as directly treating the zinc anode. This is because the contact between DPE and the zinc anode was insufficient. Treating the separator with DPE resulted in insufficiently dense in-situ induced ZHS growth, failing to inhibit further ZHS formation and failing to form an effective protective layer, leading to poor performance and ultimately a performance of less than 400 hours. Figure 8 ).

[0080] Taking Example 1 as an example, the influence of the dual interface layer formed by the method of the present invention on the performance of aqueous zinc-ion batteries is verified, with Comparative Example 1 and Comparative Example 2 as controls, as follows:

[0081] During zinc deposition, the coated DPE undergoes hydrolysis, causing pH fluctuations at the zinc anode interface, which in turn induces basic zinc sulfate to stack in parallel at the interface to form a dense protective layer. Figure 1The images show Bare Zn, DPE@Zn, and ZHS@Zn after pre-cycling with the DPE layer removed (after pre-cycling, a uniform ZHS layer (DPE / ZHS@Zn) forms in the middle of the DPE layer of Zn; after removing the DPE layer, ZHS@Zn is obtained). It can be seen that the exposed zinc surface has many scratches, which leads to uneven surface electric field and ion distribution, exacerbating zinc dendrite growth. In contrast, the DPE layer has a smooth and flat surface, effectively protecting the zinc anode. After pre-cycling, a uniform ZHS layer on the zinc surface can be observed. Figure 2 X-ray diffraction (XRD) confirmed the presence of a DPE layer on the zinc surface and the formation of ZHS. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) further revealed the surface morphology and elemental distribution of the ZHS, demonstrating its uniform formation.

[0082] The formation of ZHS can significantly alleviate the side reactions between the zinc anode and water. Figure 3 In linear sweep voltammograms (LSVs) on any metal substrate, this organic / inorganic dual-interface layer increases the hydrogen evolution overpotential, effectively mitigating the hydrogen evolution side reaction and protecting the zinc anode. Simultaneously, Figure 4 The Tafel curve shows the corrosion current of Bare Zn (icorr = 2.630 mA·cm). -2 The corrosion potential (Ecorr = -1.0081V) was significantly higher than that of the standard, while DPE / ZHS@Zn exhibited a lower corrosion current (icorr = 1.819mA·cm). -2 The high corrosion potential (Ecorr = -1.0048V) indicates that the dual interface layer (the DPE layer induces the formation of a ZHS layer between the Zn and DPE interlayers, so the final zinc surface is a dual interface layer composed of two protective layers, DPE / ZHS) can effectively inhibit the corrosion of Zn and create conditions for the reversible and uniform deposition of zinc ions.

[0083] Figure 5 This includes a chronoamperometry graph and the final optical microscope image. Figure 5 As can be seen in Figure a, the current density in the bare zinc electrode continuously increases within 3600 s, exhibiting an extremely long 2D diffusion process, which leads to the Zn... 2+ It tends to diffuse laterally along the surface and eventually deposit at the tip to form dendrites (e.g. Figure 5 (As shown in b). This contrasts sharply with DPE / ZHS@Zn, which, after confined two-dimensional diffusion, undergoes a long-term 3D diffusion process with stable and low current density, promoting uniform and flat Zn deposition and suppressing zinc dendrite growth (as shown in b). Figure 5(As shown in c), this contrasts sharply with the case of bare zinc electrodes that diffuse laterally on the surface and easily deposit dendrites at the tip.

[0084] Electrochemical test results show that at 5 mA·cm -2 Current density and 5 mAh·cm -2 At the same deposition capacity, the DPE / ZHS@Zn symmetric cell can maintain stable cycling for over 1600 hours, while Bare Zn only lasts about 150 hours, representing a performance improvement of more than ten times. Figure 6 ).

[0085] The DPE@Zn and DPE@Cu from Example 1 (the preparation method of DPE@Cu is the same as that of DPE@Zn, the only difference being that the zinc sheet is replaced with a copper sheet) were assembled into a DPE@Zn||DPE@Cu half-cell. The assembly method of the DPE@Zn||DPE@Cu half-cell is the same as that of the DPE@Zn / / DPE@Zn symmetrical cell (only the electrodes are different). The Bare Zn from Comparative Example 1 was assembled into a Bare Zn||Bare Cu half-cell. Specifically, the Bare Cu was treated in the same way as Bare Zn, and the assembly method of the Bare Zn||Bare Cu half-cell is the same as that of the Zn / / Zn symmetrical cell (only the electrodes are different). Cyclic performance was tested. At 5 mA·cm⁻¹ -2 Current density and 5 mAh·cm -2 At the deposition capacity, the DPE / ZHS@Zn||DPE / ZHS@Cu half-cell achieved a coulombic efficiency of 99.89% after 300 cycles, while the Bare Zn||Bare Cu half-cell could only maintain 30 cycles before being destroyed due to dendrite growth. Figure 7 ).

[0086] Furthermore, tests showed that the battery performance of Examples 2-7 was not significantly different from that of Example 1.

[0087] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for stabilizing the zinc anode of an aqueous zinc-ion battery, characterized in that, Includes the following steps: First, dipentaerythritol and polyvinylidene fluoride are mixed, then N-methylpyrrolidone is added and mixed evenly to obtain a slurry; The slurry is coated onto the surface of a zinc sheet and dried to obtain an electrode with a water-based coating. The coated electrode of the water system is used as the negative electrode to assemble an aqueous zinc-ion battery. The thickness of the coating is 10–30 μm; The mass ratio of dipentaerythritol to polyvinylidene fluoride is (7-9):(1-3).

2. The method for stabilizing the zinc anode of an aqueous zinc-ion battery according to claim 1, characterized in that, The mass ratio of dipentaerythritol to polyvinylidene fluoride is 9:

1.

3. The method for stabilizing the zinc anode of an aqueous zinc-ion battery according to claim 1, characterized in that, Before coating the zinc sheet with the slurry, the zinc sheet is pretreated by sanding one side of the zinc sheet with sandpaper, then rinsing it with water and anhydrous ethanol in sequence, and then drying it.

4. The method for stabilizing the zinc anode of an aqueous zinc-ion battery according to claim 1, characterized in that, The aqueous zinc-ion battery is either a symmetrical or asymmetrical battery.

5. The method for stabilizing the zinc anode of an aqueous zinc-ion battery according to claim 1, characterized in that, The coating thickness is 20 μm.

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