Hydroxypropyl cellulose modified zinc negative electrode based on double-solvent gradient volatilization regulation and preparation method thereof

Abstract

The invention belongs to the technical field of aqueous zinc ion batteries, and particularly relates to a hydroxy propyl cellulose modified zinc negative electrode based on double-solvent gradient volatilization regulation and a preparation method thereof. The preparation method comprises the following steps: 1) zinc foil pretreatment: polishing and cleaning the surface of the zinc foil to obtain a clean substrate; 2) slurry preparation: dissolving hydroxy propyl cellulose powder in a mixed solvent of acetone and ethanol, and stirring to form uniform and transparent HPC slurry; 3) blade coating of the coating: uniformly dropwise adding the HPC slurry on the surface of the zinc foil, and blade coating at a constant speed by using a scraper to obtain the HPC three-dimensional zinc-conducting network coating; and 4) drying and curing: placing the blade-coated zinc foil in the air for standing and drying to obtain the negative electrode. The negative electrode is driven by gradient dynamics and surface tension gradient in a solvent volatilization process to be self-leveled, so that a compact, defect-free and strong-adhesion protective layer is formed, zinc dendrite growth and interface side reaction are effectively inhibited, the cycle life of the battery is prolonged, and the interface stability of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery technology, specifically to a hydroxypropyl cellulose-modified zinc anode based on dual solvent gradient evaporation regulation and its preparation method. Background Technology

[0002] As the global energy structure transitions towards a low-carbon model, energy storage technology has become a core support for addressing the intermittency and volatility of renewable energy sources (solar, wind, etc.). Aqueous zinc-ion batteries (AZIBs) have emerged as a key candidate for next-generation energy storage technology due to their significant advantages: zinc is abundant and widely distributed in the Earth's crust, eliminating reliance on scarce resources and significantly reducing raw material costs and geopolitical risks; the zinc metal anode has a high theoretical specific capacity, low redox potential, and excellent electrochemical activity; and the electrolyte uses water as a solvent, making it non-toxic, non-flammable, and environmentally friendly, avoiding the safety hazards (such as fire and explosion) associated with organic electrolytes. Therefore, AZIBs have irreplaceable application prospects in large-scale grid energy storage, distributed energy storage, and portable electronic devices. As the core component of aqueous zinc-ion batteries, the interface stability and electrochemical performance of the anode directly determine the battery's cycle life, coulombic efficiency, and safety performance.

[0003] Currently, commercially available aqueous zinc-ion batteries generally use pure zinc foil as the negative electrode. However, in actual charge-discharge cycles, zinc negative electrodes face multiple problems, such as safety hazards and capacity decay caused by disordered growth of zinc dendrites, severe interfacial side reactions leading to low coulombic efficiency and a surge in impedance, and volume expansion damaging the integrity of the electrode structure. These problems severely restrict the commercialization process of AZIBs and have become a technical bottleneck that the industry urgently needs to solve.

[0004] To address the aforementioned issues, various zinc anode modification strategies have been proposed within the industry, including electrolyte additive regulation, surface coating modification, electrode structure reconstruction, and alloying modification. Among these, surface coating modification has become the most mainstream technical approach due to its ease of operation, controllable cost, and high potential for large-scale scalability. Existing coating materials are mainly classified into three categories: inorganic coatings, traditional polymer coatings, and composite coatings. However, all three types of coatings have significant drawbacks. Inorganic coatings, while capable of suppressing dendrites, require toxic solvents, have poor adhesion, and are prone to cracking. Traditional polymer coatings, while suppressing side reactions, suffer from low ion conductivity and difficulty in thickness control. Composite coatings, while balancing conductivity and flexibility, are complex to manufacture and costly, failing to meet the required standards. In recent years, existing technologies have largely focused on the chemical functions of hydroxypropyl cellulose (HPC) materials themselves, neglecting the crucial impact of film formation processes on coating quality. Therefore, developing a process system capable of precisely controlling the conformation of hydroxypropyl cellulose (HPC) molecular chains and film formation kinetics is key to realizing its commercial application. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a hydroxypropyl cellulose-modified zinc anode based on dual-solvent gradient evaporation regulation and its preparation method. The self-leveling and densification of the HPC three-dimensional zinc conductive network coating are achieved through an acetone / ethanol mixed solvent system, significantly improving the interface quality and electrochemical performance of the coating.

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

[0007] On one hand, this invention provides a hydroxypropyl cellulose-modified zinc anode based on dual-solvent gradient evaporation regulation. The anode uses zinc foil as a substrate, with a three-dimensional zinc-conducting network (HPC) coating formed by hydroxypropyl cellulose in a mixed solvent system of acetone and ethanol loaded on its surface. The HPC three-dimensional zinc-conducting network coating has a continuous and dense structure, is tightly bonded to the zinc foil, and the hydroxyl groups in the HPC molecular chain can react with Zn. 2+ To form a stable network.

[0008] On the other hand, the present invention also provides a method for preparing a hydroxypropyl cellulose-modified zinc anode based on dual solvent gradient evaporation control as described above, comprising the following steps:

[0009] S1. Zinc foil pretreatment: Sand the zinc foil with sandpaper to remove the surface oxide layer and impurities, then ultrasonically clean it with anhydrous ethanol to remove residual debris, and finally wipe it clean with lint-free paper to allow the anhydrous ethanol to evaporate completely, resulting in a clean base zinc foil.

[0010] S2, HPC slurry preparation: Hydroxypropyl cellulose powder is added to a mixed solvent composed of acetone and ethanol, and stirred at room temperature until the hydroxypropyl cellulose is completely dissolved to form a uniform and transparent hydroxypropyl cellulose slurry;

[0011] S3, HPC coating scraping: The dried zinc foil is laid flat on a clean substrate, and hydroxypropyl cellulose slurry is evenly dripped onto the zinc foil surface. The slurry is scraped at a uniform speed using a scraper to form a continuous and flat wet film, which is the HPC three-dimensional zinc conductive network coating.

[0012] S4. Coating drying and curing: Transfer the coated zinc foil to a forced-air drying oven to dry, allowing the solvent to evaporate completely. Acetone is used to increase viscosity and prevent sagging, and then ethanol is slowly evaporated to eliminate internal stress, forming a stable three-dimensional zinc conductive network coating. This results in a hydroxypropyl cellulose modified zinc anode with an HPC three-dimensional zinc conductive network coating on the zinc foil surface.

[0013] Preferably, step S1 specifically involves sanding the zinc foil with sandpaper, then ultrasonically cleaning it with anhydrous ethanol, and finally wiping it clean with lint-free paper to allow the anhydrous ethanol to completely evaporate, thereby obtaining a clean base zinc foil.

[0014] Preferably, the sandpaper used in step S1 is 600-2000 grit, and a uniform pressure of 0.5-1N is applied during sanding, sanding in the same direction; the dust-free paper is made of 100% wood pulp, and a slight pressure of 0.1-0.2N is applied during wiping, wiping 5-8 times in one direction along the long side of the zinc foil, so that a clean base zinc foil is finally obtained.

[0015] Preferably, the ratio of the hydroxypropyl cellulose powder to the mixed solvent is (0.03-0.04) g: (1.1-1.4) mL.

[0016] Preferably, the volume ratio of acetone to ethanol in the mixed solvent is 3:1 to 6:1.

[0017] Preferably, the stirring speed in step S2 is 200-400 rpm, and the stirring time is 50-70 min.

[0018] More preferably, the amount of HPC powder used in step S2 can be 0.03g, 0.032g, 0.035g, 0.038g, or 0.04g; the ratio of acetone to ethanol in the mixed solvent can be 3:1, 4:1, 5:1, or 6:1; the stirring speed can be 200rpm, 250rpm, 300rpm, 350rpm, or 400rpm; and the stirring time can be 50min, 55min, 60min, 65min, or 70min; but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0019] Preferably, the thickness of the HPC three-dimensional zinc conductive network coating (wet film) in step S3 is 100-200 μm, and the thickness of the HPC three-dimensional zinc conductive network coating (dry film) in step S4 is 3-7 μm.

[0020] Preferably, in step S4, the standing time is 8-12 minutes, the drying temperature is 50-70℃, and the drying time is 10-14 hours.

[0021] More preferably, the drying temperature in step S4 can be 50°C, 60°C, or 70°C; the drying time can be 10h, 11h, 12h, 13h, or 14h; but it is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0022] The present invention also provides an aqueous zinc-ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the negative electrode is the hydroxypropyl cellulose modified zinc negative electrode based on dual solvent gradient evaporation regulation.

[0023] Preferably, the electrolyte is a 2M zinc trifluoromethanesulfonate aqueous solution, and the diaphragm is a glass fiber diaphragm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Pioneering a new film-forming mechanism regulated by dual solvent gradient evaporation

[0026] This invention utilizes the difference in evaporation rates between acetone (boiling point 56℃) and ethanol (boiling point 78℃) to achieve a "two-step" drying kinetics. In the initial stage, the rapid evaporation of acetone increases viscosity and prevents slurry sagging; in the later stage, the slow evaporation of ethanol prolongs the "open time" of the wet film, allowing polymer chain rearrangement and relaxation, effectively eliminating internal stress and microcracks caused by rapid drying.

[0027] (2) Introducing the Marangoni effect to drive self-leveling

[0028] The mixed solvent in this invention creates a significant surface tension gradient. During solvent evaporation, the Marangoni convection induced by the composition gradient drives the liquid to flow from low surface tension regions to high surface tension regions, automatically "repairing" tiny depressions and defects on the liquid film surface, achieving self-leveling of the coating, and significantly improving the smoothness and density of the coating.

[0029] (3) Synergistic solubilization and interfacial anchoring enhance adhesion

[0030] The mixed solvent used (acetone to ethanol volume ratio of 3:1 to 6:1) falls within the good solvent range for HPC (Flory-Huggins parameter optimization), allowing the HPC molecular chains to exhibit an extended conformation rather than coiled aggregation in solution, resulting in more uniform entanglement after film formation. Simultaneously, the ethanol component can form strong hydrogen bond interactions with the oxide / hydroxyl layer on the zinc surface, significantly improving the wettability of the slurry to the substrate and resolving the "dewetting" phenomenon easily caused by acetone alone, thus greatly enhancing coating adhesion.

[0031] (4) Achieve dual improvement in electrochemical performance and interfacial stability

[0032] Experimental data fully demonstrate that the zinc anode modified by this method achieves significant breakthroughs in several key electrochemical performance indicators. Regarding long-term cycle stability, the modified anode maintains a high capacity retention rate after 1000 deep charge-discharge cycles at a high current density of 5 A / g, exhibiting excellent cycle durability. In terms of interface stability, the battery's coulombic efficiency can be stably maintained above 99%, proving the significant effect of the HPC coating in suppressing side reactions.

[0033] This invention, through the deep integration of material design and process innovation, successfully solves key technical problems such as dendrite growth and side reactions in zinc anodes while maintaining the green and economical nature of the preparation process, providing a practical and feasible technical path for promoting the commercialization of aqueous zinc-ion batteries. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a plan view of the dual-solvent slurry negative electrode prepared in Example 1 of the present invention;

[0036] Figure 2 This is a plan view of the pure ethanol solvent slurry negative electrode prepared in Comparative Example 2 of the present invention;

[0037] Figure 3 This is a plan view of the pure acetone solvent slurry negative electrode prepared in Comparative Example 3 of the present invention.

[0038] Figure 4 The images show the XRD patterns of the HPC three-dimensional zinc conductive network coated negative electrode prepared in Example 1 of the present invention and the unmodified zinc foil prepared in Comparative Example 1.

[0039] Figure 5 The HPC-Zn three-dimensional zinc network coated negative electrode (HPC-Zn) prepared in Example 1 of this invention and the unmodified zinc electrode (Zn) prepared in Comparative Example 1 were compared at a current density of 1 mA·cm⁻¹. -2 The surface capacity is 1 mAh·cm -2 A symmetrical battery charge / discharge curve;

[0040] Figure 6 The HPC-Zn three-dimensional zinc network coated negative electrode (HPC-Zn) prepared in Example 1 of this invention and the unmodified zinc electrode (Zn) prepared in Comparative Example 1 were tested at a current density of 5 mA·cm⁻¹. -2 The surface capacity is 5mAh·cm -2 A symmetrical battery charge / discharge curve;

[0041] Figure 7 The HPC-containing three-dimensional zinc network coated negative electrode (NVO / / HPC-Zn) prepared in Example 1 of this invention and the unmodified zinc electrode (NVO / / Zn) prepared in Comparative Example 1 were compared in a full cell at 5 A·g. -1 Cyclic performance at current density. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Process parameters in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer.

[0043] Example 1

[0044] A method for preparing hydroxypropyl cellulose-modified zinc anode based on dual solvent gradient evaporation regulation includes the following steps:

[0045] S1. Zinc Foil Pretreatment: Take a 0.15mm thick zinc foil and polish it using 600-grit and 2000-grit water-resistant sandpaper, applying a uniform pressure of 0.8N in the same direction to thoroughly remove the surface oxide layer and impurities. Place the polished zinc foil in anhydrous ethanol and ultrasonically clean for 12 minutes to remove residual debris. Then, using 100% wood pulp lint-free paper, apply a slight pressure of 0.15N unidirectionally and wipe the zinc foil 6 times along its long side to ensure complete evaporation of the anhydrous ethanol, resulting in a base zinc foil with a clean, active surface.

[0046] S2. Preparation of HPC slurry: Accurately weigh 0.035g of hydroxypropyl cellulose (HPC) powder and add it to a mixed solvent consisting of 1mL acetone and 0.2mL ethanol (volume ratio 5:1). At room temperature of 28°C, use a magnetic stirrer to continuously stir at 300rpm for 60 minutes until the HPC is completely dissolved, forming a homogeneous, transparent, and precipitate-free HPC slurry.

[0047] S3. HPC Coating Application: The pre-treated and dried zinc foil is spread evenly on a clean glass substrate. Using a pipette, 1 mL of HPC slurry is precisely measured and evenly added to the zinc foil surface. A 150 μm thick doctor blade is used to apply the slurry at a constant speed along the long side of the zinc foil, forming a continuous and smooth wet film. After application, the coating is allowed to stand for 10 minutes to allow the slurry to fully level, resulting in a 150 μm thick HPC three-dimensional zinc-conducting network coating.

[0048] S4. Coating Drying and Curing: The coated zinc foil is transferred to a forced-air drying oven and dried at 60°C for 12 hours. Acetone is used to preferentially evaporate to increase viscosity and prevent sagging, followed by slow evaporation of ethanol to eliminate internal stress and ensure complete solvent evaporation. During this process, HPC molecular chains form a stable three-dimensional zinc-conducting network coating through intermolecular interactions and adsorption to the zinc foil surface. At this point, the thickness of the HPC three-dimensional zinc-conducting network coating is 5μm, ultimately obtaining an HPC-modified zinc anode based on dual-solvent gradient evaporation.

[0049] Its floor plan is as follows Figure 1 As shown, by Figure 1 It can be seen that the coating has no significant pinholes or thickness gradients in its microstructure, has a continuous and dense structure, and the hydroxyl groups in the HPC molecular chain react with Zn. 2+ It forms a coordination effect, guiding the uniform migration of zinc ions.

[0050] Example 2

[0051] The difference between this embodiment and Embodiment 1 is that 0.03g of HPC powder is used in step S2, while other process parameters remain the same as in Embodiment 1.

[0052] Example 3 The difference between this example and Example 1 is that 0.04g of HPC powder is used in step S2, while other process parameters remain the same as in Example 1.

[0053] Example 4

[0054] The difference between this embodiment and embodiment 1 is that: in step S3, a 100μm thick scraper is used for scraping, and the thickness of the HPC three-dimensional zinc conductive network coating wet film is 100μm. The thickness of the HPC three-dimensional zinc conductive network coating obtained in step S4 is 4μm. Other process parameters are the same as in embodiment 1.

[0055] Example 5 The difference between this example and Example 1 is that: in step S3, a 200μm thick doctor blade is used for coating, and the thickness of the HPC three-dimensional zinc conductive network coating wet film is 200μm. The thickness of the HPC three-dimensional zinc conductive network coating obtained in step S4 is 6μm. Other process parameters are the same as in Example 1.

[0056] Example 6

[0057] The difference between this embodiment and Example 1 is that in step S2, the mixed solvent formula is adjusted, and the ratio of acetone to ethanol is changed from 5:1 to 3:1 (i.e., 1 mL of acetone is mixed with about 0.33 mL of ethanol). Other process parameters remain the same as in Example 1.

[0058] Example 7

[0059] The difference between this embodiment and Example 1 is that the ratio of acetone to ethanol is adjusted from 5:1 to 6:1 (i.e., 1 mL of acetone is mixed with about 0.17 mL of ethanol), while other process parameters remain the same as in Example 1.

[0060] Comparative Example 1: The difference between this comparative example and Example 1 is that a zinc foil with a thickness of 0.15 mm was taken and treated using the same pretreatment method as in Example 1, but without HPC coating modification, and used as a control sample.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 1 is that step S2 uses only 1.2 mL of ethanol as a solvent, without adding acetone; all other parameters are completely consistent with Example 1. The planar diagram of the negative electrode material obtained in this comparative example is shown below. Figure 2 As shown, according to Figure 2 It can be seen that the uniformity of the distribution of the obtained negative electrode material is significantly reduced compared with Example 1.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 1 is that step S2 uses only 1.2 mL of acetone as a solvent, without adding ethanol; all other parameters are completely consistent with Example 1. The planar diagram of the negative electrode material obtained in this comparative example is shown below. Figure 3 As shown, according to Figure 3 It can be seen that the product exhibits an obvious irregular polygonal morphology, and its overall uniformity and dispersibility are still inferior to the alcohol-ketone mixed solvent system of Example 1.

[0065] Coating morphology comparison and analysis: Through planar observation, it was found that the surface of the sample in Comparative Example 2 had local cracks, and the edge of the sample in Comparative Example 3 showed thickness gradients and flow marks; while the coating of the sample in Example 1 showed a highly dense continuous structure with no visible or microscopic pore defects, which confirmed the significant advantage of the mixed solvent system in film quality.

[0066] Figure 4 The figures show the XRD patterns of the HPC three-dimensional zinc network coated negative electrode prepared in Example 1 of this invention and the unmodified zinc foil prepared in Comparative Example 1. As can be seen from the figures, both samples exhibit characteristic diffraction peaks of metallic zinc, while the HPC-Zn sample shows an additional amorphous broad carbon peak near 23°, and the intensity of the characteristic zinc peak is relatively reduced.

[0067] Application Example 1

[0068] The HPC-modified zinc anode material based on dual solvent gradient evaporation prepared in Example 1 was used as the positive and negative electrodes of a symmetrical cell to assemble an HPC@Zn / / HPC-Zn symmetrical cell. The battery casing used was model CR2032. The specific assembly process is as follows: the positive electrode casing, HPC-modified zinc anode, glass fiber separator (GF / D) impregnated with 2M zinc trifluoromethanesulfonate electrolyte (130 μL per side), HPC-modified zinc anode, gasket, spring sheet, and negative electrode casing were placed in sequence, and finally encapsulation was completed under ambient temperature and atmospheric conditions.

[0069] The pure zinc foil symmetric battery (Zn / / Zn) of Comparative Example 1 was assembled using the same process, with both the positive and negative electrodes using unmodified 99% pure zinc foil, and the electrolyte system and assembly process being consistent with the experimental group mentioned above.

[0070] Test results show that the assembled HPC-Zn / / HPC-Zn symmetric cell and the Zn / / Zn symmetric cell can achieve the same current density at 1 mA cm⁻¹. -2 Surface capacity 1 mAh cm -2 The voltage-time curve under the given conditions is as follows: Figure 5 As shown in the figure. Experimental data show that the HPC-Zn / / HPC-Zn symmetric cell can achieve stable cycling for over 1000 hours without short circuit, and its electrochemical performance is significantly better than that of the pure zinc foil symmetric cell in Comparative Example 1. The assembled HPC-Zn / / HPC-Zn symmetric cell and the Zn / / Zn symmetric cell were compared at a current density of 5 mA cm⁻¹. -2 Surface capacity 5 mAh cm -2 The voltage-time curve under the given conditions is as follows: Figure 6 As shown, the data indicates that HPC-Zn / / HPC-Zn symmetric cells can achieve stable cycling for over 500 hours without short circuits.

[0071] Application Example 2

[0072] Preparation of NVO cathode material: 1g of ammonium metavanadate (NH4VO3) was dissolved in 30mL of deionized water and heated to 80℃. The solution was stirred continuously for 30 minutes until fully dissolved. Then, 2mL of hydrochloric acid was slowly added, and stirring continued for 30 minutes until homogeneous. The resulting mixture was transferred to a polytetrafluoroethylene-lined high-pressure reactor and subjected to a hydrothermal reaction at 140℃ for 24 hours. After the reaction, the mixture was allowed to cool naturally. The product was collected by centrifugation and washed three times with deionized water and anhydrous ethanol, respectively. Finally, it was dried in a vacuum oven at 60℃ for 12 hours to obtain the NVO cathode material.

[0073] The NVO positive electrode was prepared by mixing NVO material, acetylene black, and polyvinylidene fluoride in a mass ratio of 7:2:1, adding an appropriate amount of N-methylpyrrolidone solvent, and mechanically stirring to form a uniform slurry. The slurry was then coated onto a stainless steel film using a blade coating method, dried under vacuum at 90°C for 14 hours, and subsequently punched into circular electrode sheets with a diameter of 12 mm.

[0074] For full cell assembly, the NVO positive electrode was placed in the positive electrode shell of the CR2032 battery, covered with a glass fiber separator, and 2M zinc trifluoromethanesulfonate electrolyte was added until completely wetted. The HPC-modified zinc negative electrode, stainless steel gasket, spring sheet, and negative electrode shell prepared in Example 1 were then placed in sequence, and the NVO / / HPC-Zn full cell was obtained by sealing with a sealing machine.

[0075] The control group used pure zinc foil from Comparative Example 1 as the negative electrode and assembled NVO / / Zn full cells under the same process conditions.

[0076] Electrochemical performance tests showed that the specific capacity of the NVO / / HPC-Zn full cell was significantly higher than that of the control group cells at different current densities. At 5 A g -1 In long-cycle testing at current density ( Figure 7 The NVO / / HPC-Zn full cell maintained a high discharge specific capacity after 1000 cycles, demonstrating excellent cycle stability and verifying the effectiveness and applicability of HPC-modified zinc anode based on dual solvent gradient evaporation in the full cell system.

Claims

1. A hydroxypropyl cellulose-modified zinc anode based on dual-solvent gradient evaporation regulation, characterized in that, The modified zinc anode uses zinc foil as a substrate and has a hydroxypropyl cellulose film formed by a mixed solvent system of acetone and ethanol on its surface, forming an HPC three-dimensional zinc conductive network coating.

2. A method for preparing the hydroxypropyl cellulose-modified zinc anode as described in claim 1, characterized in that, Includes the following steps: S1. Zinc foil pretreatment: The zinc foil surface is polished and cleaned to obtain a clean substrate; S2. Slurry preparation: Utilizing the co-solvent effect, hydroxypropyl cellulose powder is added to a mixed solvent composed of acetone and ethanol, and stirred until the hydroxypropyl cellulose is completely dissolved to form a uniform and transparent hydroxypropyl cellulose slurry. S3. Coating application: The dried zinc foil is laid flat on a clean substrate. Hydroxypropyl cellulose slurry is evenly dripped onto the zinc foil surface and coated at a uniform speed with a scraper to form a continuous and flat wet film, thus obtaining the HPC three-dimensional zinc conductive network coating. S4. Drying and curing: Place the coated zinc foil in the air to stand, and then dry it to obtain a hydroxypropyl cellulose modified zinc anode with an HPC three-dimensional zinc conductive network coating on the zinc foil surface.

3. The preparation method according to claim 2, characterized in that, Step S1 specifically involves sanding the zinc foil with sandpaper, then ultrasonically cleaning it with anhydrous ethanol, and finally wiping it clean with lint-free paper to allow the anhydrous ethanol to completely evaporate, resulting in a clean base zinc foil.

4. The preparation method according to claim 3, characterized in that, The sandpaper is 600-2000 grit. When sanding, apply a uniform pressure of 0.5-1N and sand in the same direction. The dust-free paper is made of 100% wood pulp. When wiping, apply a slight pressure of 0.1-0.2N and wipe 5-8 times in one direction along the long side of the zinc foil.

5. The preparation method according to claim 2, characterized in that, In step S2, the ratio of the amount of hydroxypropyl cellulose powder to the mixed solvent is (0.03-0.04) g: (1.1-1.4) mL.

6. The preparation method according to claim 2, characterized in that, In step S2, the volume ratio of acetone to ethanol in the mixed solvent is 3:1 to 6:

1.

7. The preparation method according to claim 2, characterized in that, The thickness of the HPC three-dimensional zinc-conducting network coating in step S3 is 100-200 μm, and the thickness of the HPC three-dimensional zinc-conducting network coating in step S4 is 3-7 μm.

8. The preparation method according to claim 2, characterized in that, In step S4, the standing time is 8-12 minutes, the drying temperature is 50-70℃, and the drying time is 10-14 hours.

9. An aqueous zinc-ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, characterized in that, The negative electrode is the hydroxypropyl cellulose modified zinc negative electrode based on dual solvent gradient evaporation control as described in claim 1, or the hydroxypropyl cellulose modified zinc negative electrode prepared by any one of claims 2 to 8.

10. The aqueous zinc-ion battery according to claim 9, characterized in that, The electrolyte is a 2M zinc trifluoromethanesulfonate aqueous solution, and the diaphragm is a glass fiber diaphragm.

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