A method for preparing a metallic zinc anode interface coating for an aqueous zinc-ion battery

Abstract

This invention provides a method for preparing an interfacial coating for a zinc-metal anode in an aqueous zinc-ion battery, belonging to the field of new energy technology. The method includes: dissolving tetrafluoroterephthalonitrile and 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindene in N,N-dimethylformamide; adding potassium carbonate and stirring in an oil bath to obtain a polymer precursor reaction solution; then preparing a polymer solid powder and dissolving it in dimethyl sulfoxide; adding potassium carbonate and hydrogen peroxide; stirring and transferring to deionized water to obtain a reaction solution; subsequently allowing it to stand to form a suspension; centrifuging to obtain a microporous polymer colloidal solution; coating this colloidal solution onto a pretreated zinc foil and drying it to obtain a zinc-metal anode for an aqueous zinc-ion battery with a microporous polymer interfacial coating. This invention can effectively suppress dendrite growth and side reactions in the zinc anode, improving the cycle life, stability, and electrochemical performance of the aqueous zinc-ion battery.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a method for preparing a zinc metal anode interface coating for aqueous zinc-ion batteries. Background Technology

[0002] With the current energy structure shifting towards cleaner and lower-carbon energy sources, and the increasing demand for high-performance energy storage devices from portable electronic devices, electric vehicles, and large-scale energy storage systems, the research and development of rechargeable battery technology has become a major development trend in the new energy field. The non-renewable nature of traditional fossil fuels and the growing environmental pollution associated with them have prompted the scientific and industrial communities to focus on energy storage technologies that combine high energy density, long cycle life, and environmental friendliness. Among these, rechargeable batteries, due to their ability to be repeatedly charged and discharged, occupy a key position in various energy storage scenarios. While lithium-ion batteries have achieved widespread application due to their high energy density, their limitations in safety (such as susceptibility to thermal runaway), cost (such as reliance on rare metals), and cycle stability have led research to gradually shift towards rechargeable battery systems with greater resource advantages and safety potential, such as sodium-ion, potassium-ion, and zinc-ion batteries.

[0003] Among various rechargeable batteries, aqueous zinc-ion batteries, due to their use of aqueous electrolyte, are non-flammable and have good environmental compatibility. Furthermore, zinc as the negative electrode material possesses a high theoretical capacity (820 mAh g). -1 5855mAhcm -2 Zinc-ion batteries possess significant advantages such as low redox potential (relative to -0.76V for the standard hydrogen electrode), abundant crustal reserves (zinc is a common metallic element with low resource acquisition costs), and low biotoxicity, making them a key research target for replacing traditional lithium-ion batteries and adapting to medium-to-large-scale energy storage scenarios. Currently, industry research on aqueous zinc-ion batteries has gradually shifted from electrolyte system optimization and cathode material development to improving anode performance. As the main carrier for zinc ion deposition / dissolution during battery charging and discharging, the performance of the zinc anode directly determines the overall cycle life and safety of the battery. Therefore, technological exploration surrounding zinc anode modification has become a crucial link in the industrialization process of aqueous zinc-ion batteries.

[0004] However, existing aqueous zinc-ion batteries still face significant technical challenges with their zinc anodes: in aqueous electrolyte environments, uneven zinc ion deposition easily occurs on the zinc anode surface, forming sharp zinc dendrites. Dendrite growth not only punctures the battery separator, causing short circuits between the positive and negative electrodes and posing safety hazards, but also leads to side reactions with the aqueous electrolyte (such as hydrogen evolution and zinc surface oxidation), resulting in electrode corrosion and loss of active materials. Furthermore, reaction products easily form a passivation layer on the electrode surface, hindering normal zinc ion transport and further shortening battery cycle life and reducing charge-discharge efficiency. Although attempts have been made to improve zinc anode performance through electrolyte additives and electrode surface roughening, these methods generally suffer from complex manufacturing processes, unstable protection effects, or high costs, failing to fundamentally address the pain points of zinc dendrite growth and electrode corrosion, severely limiting the commercial application of aqueous zinc-ion batteries. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the present invention aims to provide a method for preparing an interfacial coating for the zinc metal anode of an aqueous zinc-ion battery. By preparing a microporous polymer colloidal solution and coating it onto the surface of a pretreated zinc metal foil to form a dense microporous polymer interfacial coating, the method effectively suppresses dendrite growth, side reactions, corrosion, and passivation problems of the zinc metal anode in aqueous zinc-ion batteries, significantly improving the cycle life, stability, safety, and electrochemical performance of the battery, and providing technical support for the commercial application of aqueous zinc-ion batteries.

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

[0007] A method for preparing a metallic zinc anode interface coating for an aqueous zinc-ion battery includes the following steps:

[0008] S1. Tetrafluoroterephthalonitrile and 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane were dissolved together in N,N-dimethylformamide, potassium carbonate was added, and the mixture was stirred in an oil bath to obtain a polymer precursor reaction solution.

[0009] S2. Add deionized water to the polymer precursor reaction solution to stop the reaction, let it stand, filter it, collect the solid precipitate obtained by filtration, dry the solid precipitate and grind it to obtain polymer solid powder.

[0010] S3. Dissolve the polymer solid powder in dimethyl sulfoxide, stir to dissolve, add potassium carbonate and continue stirring, then add hydrogen peroxide dropwise and continue stirring, finally transfer the reaction system to deionized water and continue stirring to obtain the reaction solution;

[0011] S4. The stirred reaction solution is allowed to stand to form a suspension, and the suspension is centrifuged to collect the liquid components obtained by centrifugation, which is the colloidal solution for microporous polymer interface coating.

[0012] S5. After pretreating the zinc foil, a treated zinc foil is obtained. The colloidal solution is then coated onto the surface of the treated zinc foil, and the coated zinc foil is dried to obtain a zinc anode for an aqueous zinc-ion battery with a microporous polymer interface coating.

[0013] Preferably, in S1, the molar ratio of the tetrafluoroterephthalonitrile to 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane is 1:1, and the molar ratio of the added potassium carbonate to the tetrafluoroterephthalonitrile is 2.5:1.

[0014] Preferably, in S1, the stirring temperature in the oil bath is 60~70°C, and the stirring reaction time after adding potassium carbonate is 48~72h.

[0015] Preferably, in step S2, the solid precipitate is washed sequentially with chloroform and methanol during filtration to remove impurities from the surface of the solid precipitate; and the solid precipitate is dried in a vacuum oven at a temperature of 50-60°C for 10-14 hours. The dried solid precipitate is then ground into powder using a mortar and pestle to obtain the polymer solid powder.

[0016] Preferably, in step S3, after the polymer solid powder is dissolved in dimethyl sulfoxide, it is stirred at 18~22°C for 0.5~1.5h until the polymer solid powder is completely dissolved. Then, potassium carbonate is added to the mixed solution of the polymer solid powder dissolved in dimethyl sulfoxide, and the mass ratio of the polymer solid powder to the added potassium carbonate is 1:1.5.

[0017] Preferably, in step S3, after adding the potassium carbonate, the mixture of the polymer solid powder dissolved in dimethyl sulfoxide is stirred for 4-5 hours, and then 7-9 mL of hydrogen peroxide is added dropwise to the mixture. After the addition, the mixture is stirred continuously at 18-22°C for 22-26 hours.

[0018] Preferably, in step S3, the mixed solution after adding hydrogen peroxide dropwise and stirring continuously is transferred to 450-550 mL of deionized water and stirred continuously at 18-22°C for 5-8 h to obtain the reaction solution.

[0019] Preferably, in S4, the centrifugation speed is 6500~7500 r / min and the processing time is 2~4 min.

[0020] Preferably, in step S5, the pretreatment of the zinc foil is as follows: immersing the zinc foil in dilute hydrochloric acid for 25-35 minutes, and then washing it repeatedly with deionized water until the rinsing solution is neutral, thereby obtaining the treated zinc foil.

[0021] Preferably, in step S5, the colloidal solution is coated onto the zinc foil surface using a coater; the coated zinc foil is then placed in a vacuum oven at 55-65°C and dried for 8-10 hours to allow the colloidal solution to solidify and form a dense microporous polymer interface coating.

[0022] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0023] (1) The present invention prepares a polymer precursor reaction solution by reacting tetrafluoroterephthalonitrile with 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-helical bisindenium to form a polymer precursor reaction solution, and then processes it to obtain a polymer solid powder, which is then prepared into a colloidal solution for microporous polymer interface coating. This solution is coated on the surface of the pretreated zinc foil to form a dense microporous polymer interface coating. This coating can effectively isolate the direct contact between the aqueous electrolyte and the metallic zinc anode, inhibit dendrite growth caused by uneven zinc ion deposition from the source, and block the side reactions between the zinc anode and the electrolyte (such as hydrogen evolution reaction and zinc surface oxidation), avoiding electrode corrosion and passivation layer formation. This solves the performance defects of zinc anode in aqueous zinc-ion batteries in the prior art.

[0024] (2) The microporous polymer interface coating prepared by the present invention has a large specific surface area and rich microporous structure. Combined with the uniformity of the microporous polymer interface coating coating process using colloidal solution, it can provide a stable transport channel for zinc ions, promote the uniform deposition and dissolution of zinc ions on the negative electrode surface, and improve the stability of the electrode structure through the physical constraint effect of the coating. It can also significantly reduce the impedance change during the charging and discharging process, thereby improving the cycle life and charging and discharging efficiency of the aqueous zinc-ion battery and ensuring the stability of the electrochemical performance of the battery during long-term use.

[0025] (3) The preparation method of the present invention is simple and efficient. From the preparation of polymer precursor reaction solution, the synthesis of colloidal solution for microporous polymer interface coating to coating and drying of microporous polymer interface coating, all adopt conventional laboratory and industrial production equipment. No complex process and special consumables are required. It takes into account both preparation efficiency and cost advantages. Moreover, the pretreated zinc foil and microporous polymer interface coating are tightly bonded. The coating is not easy to fall off after curing. It is suitable for large-scale mass production and provides key technical support for the commercial application of aqueous zinc-ion batteries. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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 drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart illustrating a method for preparing a metallic zinc anode interface coating for an aqueous zinc-ion battery according to the present invention.

[0028] Figure 2 The infrared spectrum of the colloidal solution provided in Example 1 of this invention after freeze-drying and PIM-1;

[0029] Figure 3 Long-cycle curve of a symmetrical battery assembled with modified zinc electrode sheet provided in Embodiment 1 of the present invention;

[0030] Figure 4 This is a long-cycle curve of a full cell assembled with a modified zinc electrode sheet and NVO provided in Embodiment 1 of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1 As shown, this invention provides a method for preparing a zinc metal anode interface coating for an aqueous zinc-ion battery, comprising the following steps:

[0034] S1. Tetrafluoroterephthalonitrile and 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane are dissolved together in N,N-dimethylformamide. After adding potassium carbonate, the mixture is placed in an oil bath and stirred to obtain the polymer precursor reaction solution.

[0035] Specifically, the molar ratio of tetrafluoroterephthalonitrile to 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane is 1:1, ensuring that both monomer raw materials undergo sufficient polymerization to form a well-structured polymer backbone and avoiding unreacted material residue due to excessive monomer raw materials. The molar ratio of potassium carbonate to tetrafluoroterephthalonitrile is 2.5:1. Potassium carbonate acts as an acid-binding agent, promptly neutralizing the hydrofluoric acid generated in the reaction, promoting the polymerization reaction in the forward direction, and improving the reaction conversion rate. Furthermore, the stirring temperature in the oil bath is 60~70℃, and the stirring reaction time after adding potassium carbonate is 48~72h, thus ensuring the reactivity of the monomer raw materials, avoiding excessively slow reaction rates due to low temperatures, and preventing solvent evaporation or thermal degradation of the polymer due to high temperatures. In addition, sufficient reaction time ensures that the monomer raw materials fully polymerize to form a polymer with uniform molecular weight.

[0036] S2. Add deionized water to the polymer precursor reaction solution to stop the reaction, let it stand, filter it, collect the solid precipitate obtained by filtration, dry the solid precipitate and grind it to obtain polymer solid powder.

[0037] Specifically, during filtration, the solid precipitate is washed sequentially with chloroform and methanol. Chloroform dissolves residual hydrophobic unreacted monomer raw materials, while methanol removes hydrophilic byproducts, such as potassium carbonate residue on the solid precipitate, achieving efficient removal of impurities and ensuring polymer purity. The solid precipitate is dried in a vacuum oven at 50-60°C for 10-14 hours. This rapidly removes adsorbed solvents from the precipitate while avoiding polymer thermal decomposition and ensuring complete evaporation of moisture, preventing residual solvents from affecting subsequent dissolution. The dried solid precipitate is then ground into powder using a mortar and pestle to obtain the polymer solid powder. Grinding increases the polymer's specific surface area, shortens the subsequent dissolution time in dimethyl sulfoxide, and ensures uniform powder particle size, preventing uneven dissolution due to particle agglomeration and improving the uniformity of subsequent modification reactions.

[0038] S3. Dissolve the polymer solid powder in dimethyl sulfoxide, stir to dissolve, add potassium carbonate and continue stirring, then add hydrogen peroxide dropwise and continue stirring, finally transfer the reaction system to deionized water and continue stirring to obtain the reaction solution.

[0039] Specifically, after the polymer solid powder is dissolved in dimethyl sulfoxide, it is stirred at 18~22℃ for 0.5~1.5h until the polymer solid powder is completely dissolved. 18~22℃ is the optimal dissolution temperature of polymer solid powder in dimethyl sulfoxide, which can ensure solvent stability, avoid solvent evaporation due to high temperature or incomplete dissolution due to low temperature, and ensure that the polymer solid powder is completely dissolved to form a homogeneous and transparent solution, providing a stable system for subsequent modification reactions.

[0040] Subsequently, potassium carbonate is added to a mixed solution in which the polymer solid powder is dissolved in dimethyl sulfoxide. The mass ratio of the polymer solid powder to the added potassium carbonate is 1:1.5 to provide and maintain the alkaline environment required for the reaction, ensuring that hydrogen peroxide can effectively oxidize and modify the cyano groups and other groups on the polymer molecular chain. Furthermore, after adding potassium carbonate, the mixture of polymer solid powder dissolved in dimethyl sulfoxide is stirred for 4-5 hours to allow potassium carbonate to fully react with the polymer and activate the reaction sites on the molecular chain. Subsequently, 7-9 mL of hydrogen peroxide is added dropwise to the mixture. Hydrogen peroxide can act as an oxidant, introducing active groups such as hydroxyl and amide groups into the polymer molecular chain under alkaline conditions, thereby enhancing the bonding force between the subsequent colloidal solution and the zinc foil. After the addition, the mixture is stirred continuously at 18-22°C for 22-26 hours to ensure complete oxidation modification and avoid uneven introduction of active groups. Finally, the mixture after adding hydrogen peroxide and continuous stirring is transferred to 450-550 mL of deionized water and stirred continuously at 18-22°C for 5-8 hours to obtain the reaction solution. This solvent displacement transforms the polymer from a dissolved state to a colloidal particle state, ensuring sufficient dispersion of the colloidal particles, preventing agglomeration, and resulting in uniform particle size.

[0041] S4. The stirred reaction solution is allowed to stand to form a suspension, and the suspension is centrifuged to collect the liquid components obtained by centrifugation, thus obtaining a colloidal solution for microporous polymer interface coating.

[0042] Specifically, the centrifugation speed is 6500~7500 r / min and the processing time is 2~4 min. Based on this, incompletely dispersed solid particles in the suspension can be separated efficiently, while avoiding excessive centrifugation that could cause colloidal particles to settle, ensuring that the collected liquid components are a homogeneous and stable colloidal solution. Removing solid particles can prevent bumps or defects from appearing on the coating surface during subsequent coating, ensuring the density and uniformity of the coating, thereby improving the coating's protective effect on the zinc anode.

[0043] S5. After pretreating the zinc foil, a treated zinc foil is obtained. The colloidal solution is then coated onto the surface of the treated zinc foil, and the coated zinc foil is dried to obtain a zinc anode for an aqueous zinc-ion battery with a microporous polymer interface coating.

[0044] Specifically, the pretreatment of zinc foil involves immersing the zinc foil in dilute hydrochloric acid for 25-35 minutes, followed by repeated washing with deionized water until the rinsing solution is neutral, resulting in treated zinc foil. The dilute hydrochloric acid reacts with the oxide layer (ZnO) on the zinc foil surface to generate soluble zinc chloride, simultaneously removing surface oil and ensuring thorough oxide layer removal without excessive corrosion of the zinc foil substrate. Repeated washing with deionized water until the rinsing solution is neutral prevents residual hydrochloric acid from causing subsequent corrosion of the zinc foil, providing a clean surface for the tight bonding of the colloidal solution and the zinc foil. Subsequently, a coating applicator is used to coat the zinc foil surface with the colloidal solution. The applicator allows for precise control of the coating thickness, ensuring uniform coverage of the zinc foil surface and preventing localized cracking due to excessive thickness or insufficient protection due to insufficient thickness. The coated zinc foil is then dried in a vacuum oven at 55-65℃ for 8-10 hours. This process promotes the orderly accumulation of polymer colloidal particles, forming a dense interfacial coating with a uniform microporous structure. It also prevents macroscopic cracks or defects in the interfacial coating caused by rapid solvent evaporation. Simultaneously, this dense coating not only isolates the aqueous electrolyte from direct contact with the zinc anode, inhibiting zinc dendrite growth and electrode corrosion, but also promotes uniform zinc ion transport through its microporous structure, improving the battery's cycle stability and electrochemical performance.

[0045] The above content will be further elaborated below through specific implementation methods. It should be noted that the English annotations in the following embodiments correspond to the following explanations:

[0046] TFTPN stands for tetrafluoroterephthalonitrile, TTSBI stands for 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane, PIM-1 is a microporous polymer powder generated by the reaction of tetrafluoroterephthalonitrile with 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane, PC is an abbreviation for PIM-CONH2, which is a microporous polymer coating obtained by reacting tetrafluoroterephthalonitrile (TFTPN) with 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane (TTSBI) to generate PIM-1 powder, and then modifying it with potassium carbonate, oxidizing it with hydrogen peroxide, and dispersing it with deionized water. PC@Zn anode material is a metallic zinc anode material with a PC microporous polymer coating on its surface.

[0047] Example 1

[0048] In this embodiment, a preparation process for a zinc-metal anode material for an aqueous zinc-ion battery with a microporous polymer interface coating is provided, specifically including:

[0049] First, the process for preparing the zinc anode coating material is as follows: 1 mmol of TFTPN and 1 mmol of TTSBI are dissolved in 50 mL of N,N-dimethylformamide. Then, 2.5 mmol of potassium carbonate is added to the reaction system, and the mixture is stirred in an oil bath at 65 °C for 48 h. After the reaction is completed, deionized water is added to stop the reaction. After standing, the mixture is filtered, and the solid precipitate obtained by filtration is placed in a vacuum oven at 50 °C for 12 h. After drying, it is ground with a mortar and pestle to obtain PIM-1 powder. Then, 0.5 g of the obtained PIM-1 powder is dissolved in 60 mL of dimethyl sulfoxide under stirring. After 1 h, 0.75 g of potassium carbonate is added and stirring is continued to dissolve. After stirring for 4 h, 8 mL of hydrogen peroxide is added dropwise to the above solution and stirring is continued. Finally, deionized water is added and stirring is continued for 5 h. After standing, the resulting suspension is centrifuged to obtain the colloidal solution for preparing the PC microporous polymer coating.

[0050] like Figure 2 As shown, this figure is a comparison of the infrared spectra of the freeze-dried product (PC) of the colloidal solution for microporous polymer interface coating and PIM-1 powder in this embodiment. The black curve corresponds to PIM-1, with a peak at approximately 2200 cm⁻¹. -1 The characteristic peak at [value] is the stretching vibration peak of the cyano group (CN); the red curve corresponds to the disappearance of the cyano characteristic peak of PC and PIM-1, and the peak is located between 3300 and 3500 cm⁻¹. -1 The presence of the characteristic absorption peak of NH in the amide group indicates that the cyano group of PIM-1 was successfully converted into an amide group during the modification process in Example 1, proving the effective synthesis of the PC microporous polymer and laying the structural foundation for the subsequent protective effect of the coating on the zinc anode.

[0051] Secondly, the process for preparing the zinc anode coating material electrode sheet is as follows: after immersing the zinc foil in dilute hydrochloric acid for 30 minutes, it is taken out and washed repeatedly with deionized water to remove surface impurities. Then, the colloidal solution for preparing PC microporous polymer coating is uniformly coated on the pretreated zinc foil using a coater. Finally, it is placed in a vacuum oven and dried at 60°C for 8 hours to obtain PC@Zn anode material.

[0052] Finally, the obtained PC@Zn anode material was sliced ​​into electrode sheets with a diameter of 14 mm using a slicer. One zinc anode sheet was then placed into the anode shell, with the coated side in contact with the separator. A glass fiber separator was then placed in, and 100 μL of 2 mol / L zinc sulfate electrolyte was added dropwise using a pipette. For assembling a symmetrical battery, the coated side was again placed in contact with the separator, followed by the placement of a gasket and a spring. Finally, the positive electrode shell was attached, and the battery was sealed using a battery packaging machine to obtain the modified zinc anode aqueous zinc-ion button battery.

[0053] like Figure 3As shown in the figure, this is a symmetrical battery assembled using PC@Zn anode material in this embodiment at 0.5 mA cm⁻¹. -2 0.5mAh cm -2 A long-cycle curve under certain conditions. (From...) Figure 3 As can be seen, the PC@Zn symmetric battery maintained a stable voltage with almost no obvious polarization during a 1200-hour cycle. This indicates that the PC microporous polymer coating can effectively suppress zinc dendrite growth and ensure the structural stability of the zinc anode during long-term charge and discharge, demonstrating the excellent cycle stability of the modified zinc anode of this invention.

[0054] like Figure 4 As shown in the figure, this is a full cell (PC@Zn / / NVO) assembled with PC@Zn anode material and NVO cathode material in this embodiment at 5Ag. -1 Long-cycle curves at current density. The black curve corresponds to the change in battery specific capacity, and the red curve corresponds to the change in coulombic efficiency. Figure 4 As can be seen, the coulombic efficiency of the full cell remained above 90% throughout 1000 cycles, and the specific capacity decayed slowly. This indicates that the PC microporous polymer coating can not only stabilize the zinc anode interface, but also work synergistically with the NVO cathode to give the full cell excellent cycle stability and high coulombic efficiency, further verifying the practical value of the modified zinc anode of this invention.

[0055] Example 2

[0056] The difference between this embodiment and Embodiment 1 lies in the preparation of the zinc negative electrode coating material and the preparation of the zinc negative electrode coating material electrode sheet; the rest are the same. This embodiment specifically includes:

[0057] The process for preparing the zinc anode coating material is as follows: 2 mmol of TFTPN and 2 mmol of TTSBI are dissolved in 80 mL of N,N-dimethylformamide. Then, 5 mmol of potassium carbonate is added to the reaction system, and the mixture is stirred in an oil bath at 65 °C for 60 h. After the reaction is completed, deionized water is added to stop the reaction. After standing, the mixture is filtered, and the solid precipitate obtained by filtration is placed in a vacuum oven at 50 °C for 12 h. After drying, it is ground with a mortar and pestle to obtain PIM-1 powder. Then, 0.5 g of the obtained PIM-1 powder is dissolved in 60 mL of dimethyl sulfoxide under stirring. After 1 h, 0.75 g of potassium carbonate is added and stirring is continued to dissolve. After stirring for 4.5 h, 8 mL of hydrogen peroxide is added dropwise to the above solution and stirring is continued. Finally, deionized water is added and stirring is continued for 6.5 h. After standing, the resulting suspension is centrifuged to obtain the colloidal solution for preparing PC microporous polymer coating.

[0058] The process for preparing zinc anode coating material electrode sheet is as follows: zinc foil is immersed in dilute hydrochloric acid for 30 minutes and then taken out and washed repeatedly with deionized water to remove surface impurities. Then, the colloidal solution for preparing PC microporous polymer coating is uniformly coated on the pretreated zinc foil using a coater. Finally, it is placed in a vacuum oven and dried at 60°C for 9 hours to obtain PC@Zn anode material.

[0059] Example 3

[0060] The difference between this embodiment and Embodiment 1 lies in the preparation of the zinc negative electrode coating material and the preparation of the zinc negative electrode coating material electrode sheet; the rest are the same. This embodiment specifically includes:

[0061] The process for preparing the zinc anode coating material is as follows: 3 mmol of TFTPN and 3 mmol of TTSBI are dissolved in 80 mL of N,N-dimethylformamide. Then, 7.5 mmol of potassium carbonate is added to the reaction system, and the mixture is stirred in an oil bath at 65 °C for 72 h. After the reaction is completed, deionized water is added to stop the reaction. After standing, the mixture is filtered, and the solid precipitate obtained by filtration is placed in a vacuum oven at 50 °C for 12 h. After drying, it is ground with a mortar and pestle to obtain PIM-1 powder. Then, 0.5 g of the obtained PIM-1 powder is dissolved in 60 mL of dimethyl sulfoxide under stirring. After 1 h, 0.75 g of potassium carbonate is added and stirring is continued to dissolve. After stirring for 5 h, 8 mL of hydrogen peroxide is added dropwise to the above solution and stirring is continued. Finally, deionized water is added and stirring is continued for 8 h. After standing, the resulting suspension is centrifuged to obtain the colloidal solution for preparing PC microporous polymer coating.

[0062] The process for preparing zinc anode coating material electrode sheet is as follows: zinc foil is immersed in dilute hydrochloric acid for 30 minutes and then taken out and washed repeatedly with deionized water to remove surface impurities. Then, the colloidal solution for preparing PC microporous polymer coating is uniformly coated on the pretreated zinc foil using a coater. Finally, it is placed in a vacuum oven and dried at 60°C for 10 hours to obtain PC@Zn anode material.

[0063] Therefore, the above-mentioned method for preparing an interfacial coating for the zinc anode of an aqueous zinc-ion battery, by preparing a microporous polymer colloidal solution and coating it onto the surface of a pretreated zinc foil to form a dense microporous polymer interfacial coating, effectively suppresses dendrite growth, side reactions, corrosion, and passivation problems of the zinc anode in aqueous zinc-ion batteries, significantly improving the cycle life, stability, safety, and electrochemical performance of the battery, and providing technical support for the commercial application of aqueous zinc-ion batteries.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0065] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing an aqueous zinc-ion battery metal zinc anode interfacial coating, characterized in that, Comprise the following steps: S1, tetrafluoro terephthalonitrile and 5,5', 6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spiral double indane are dissolved in N,N-dimethylformamide, after adding potassium carbonate, stirring in oil bath, to obtain the polymer precursor reaction solution; S2, stop the reaction by adding deionized water to the polymer precursor reaction solution, after standing, suction filtration, and collecting the solid precipitate obtained by suction filtration, and drying the solid precipitate, grinding, to obtain a polymer solid powder; S3, the polymer solid powder is dissolved in dimethyl sulfoxide, after stirring and dissolving, add potassium carbonate and continue stirring, then add hydrogen peroxide dropwise and continue stirring, finally transfer the reaction system to deionized water and continue stirring, to obtain a reaction solution; S4, the reaction solution after stirring is placed to form a suspension, and the suspension is centrifuged to collect the liquid component obtained by centrifugation, to obtain a colloidal solution for microporous polymer interface coating; S5, the zinc foil is pretreated to obtain a treated zinc foil, the colloidal solution is coated on the surface of the treated zinc foil, and the coated zinc foil is dried to obtain a water-based zinc ion battery metal zinc negative electrode with microporous polymer interface coating.

2. The method of claim 1, wherein the method is characterized by: In S1, the molar ratio of tetrafluoro terephthalonitrile to 5,5', 6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spiral double indane is 1:1, and the molar ratio of potassium carbonate added to tetrafluoro terephthalonitrile is 2.5:

1.

3. The method of claim 1, wherein the method is characterized by: In S1, the stirring temperature in the oil bath is 60~70℃, and the stirring reaction time after adding potassium carbonate is 48~72h.

4. The method of claim 1, wherein the method is characterized by: In S2, the solid precipitate is washed with chloroform and methanol in sequence during suction filtration to remove impurities on the surface of the solid precipitate; and the solid precipitate is dried in a vacuum oven, the drying temperature is 50~60℃, the drying time is 10~14h, the solid precipitate after drying is ground to powder in a mortar to obtain the polymer solid powder.

5. The method of claim 1, wherein the method is characterized by: In S3, after the polymer solid powder is dissolved in dimethyl sulfoxide, it is stirred at 18~22℃ for 0.5~1.5h until the polymer solid powder is completely dissolved, then potassium carbonate is added to the mixed solution of the polymer solid powder dissolved in dimethyl sulfoxide, and the mass ratio of the polymer solid powder to the added potassium carbonate is 1:1.

5.

6. The method of claim 5, wherein the method further comprises: In S3, after adding the potassium carbonate, the mixed solution of the polymer solid powder dissolved in dimethyl sulfoxide is continuously stirred for 4~5h, then 7~9mL of hydrogen peroxide is added dropwise to the mixed solution, and the mixed solution is continuously stirred at 18~22℃ for 22~26h after dropwise addition.

7. The method of claim 6, wherein the method further comprises the step of: In S3, the mixed solution after adding hydrogen peroxide and continuously stirring is transferred to 450~550mL of deionized water, and continuously stirred at 18~22℃ for 5~8h to obtain the reaction solution. ​ 8. The method of claim 1, wherein the method is characterized by: In S4, the centrifugal treatment is at a speed of 6500~7500r / min for 2~4min.

9. The method of claim 1, wherein the method is characterized by: In S5, the pretreatment of the zinc foil is as follows: the zinc foil is soaked in dilute hydrochloric acid for 25-35 min, and then washed with deionized water for multiple times until the washing liquid is neutral, to obtain the treated zinc foil.

10. The method of claim 1, wherein the method is characterized by: In S5, the colloidal solution is coated on the surface of the zinc foil by using a coater scraping coating method; the coated zinc foil is placed in a vacuum oven at 55-65 DEG C for 8-10 h for drying, so that the colloidal solution is solidified to form a dense microporous polymer interface coating.

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