Zinc phytate-zinc-polyanion gel-coated zinc negative electrodes and methods of making and using the same

Abstract

The application belongs to the technical field of zinc ion battery negative electrode materials, and particularly relates to a zinc phytate-polyanion gel coating zinc negative electrode and a preparation method and application thereof, and comprises the following steps: pretreating a zinc sheet, immersing the zinc sheet in a zinc phytate aqueous solution to prepare a zinc phytate-coated zinc sheet; mixing acrylamide, 2-acrylamido-2-methylpropanesulfonic acid sodium, N,N'-methylenebisacrylamide, a photoinitiator and water to prepare a pre-gel aqueous solution; covering the pre-gel aqueous solution on the surface of the zinc phytate-coated zinc sheet, and using ultraviolet light to initiate the formation of a polyanion gel coating to obtain a zinc phytate-polyanion gel coating zinc negative electrode. The zinc phytate coating is generated in situ by a chemical conversion method; the zinc phytate coating and the polyanion gel layer are connected by hydrogen bonds, which promotes the close combination of the polyanion gel layer and the zinc phytate, reduces the impedance and improves the cycle stability of the zinc negative electrode coating.

Description

Technical Field

[0001] This invention belongs to the technical field of zinc-ion battery anode materials, specifically relating to zinc phytate-polyanion gel coated zinc anode, its preparation method, and its application. Background Technology

[0002] With the rapid development of battery energy storage technology and the huge demand from fields such as energy storage, electric vehicles, and electronic devices, researchers are constantly exploring and developing new rechargeable battery technologies that are highly safe, stable in performance, low in cost, and environmentally friendly. Aqueous zinc-ion batteries, as one such technology, have attracted attention due to their good safety, low cost, and high capacity. However, the formation of zinc dendrites on the negative electrode and the interface corrosion side reactions in aqueous zinc-ion batteries seriously hinder their commercial application. Dendrite formation significantly reduces battery safety and cycle life. Solving and optimizing the problems of zinc dendrite formation and interface corrosion is essential for the commercial application of aqueous zinc-ion batteries and is currently a key research direction for researchers.

[0003] In zinc anode stabilization strategies, constructing a solid-state interfacial protective layer is the most direct and effective approach. Inorganic interfacial coatings have attracted widespread attention due to their ability to guide uniform zinc ion deposition by possessing uniform ion transport channels or zinc-loving sites. However, during cycling, especially at high capacities, changes in anode volume can easily lead to cracking or even detachment of rigid inorganic coatings, resulting in interfacial coating protection failure and making it difficult to maintain long-term protection. Furthermore, the low Zn content of the coating... 2+ Conductivity limits the performance of the negative electrode during high-current cycling. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a zinc phytate-polyanion gel-coated zinc anode, its preparation method, and its application.

[0005] The present invention is specifically implemented through the following technical solution.

[0006] The first objective of this invention is to provide a method for preparing a zinc phytate-polyanion gel-coated zinc anode, comprising the following steps:

[0007] Zinc sheets are pretreated and then immersed in phytic acid aqueous solution to prepare phytic acid-coated zinc sheets.

[0008] A pregel aqueous solution was prepared by mixing acrylamide, sodium 2-acrylamido-2-methylpropanesulfonate, N,N'-methylenebisacrylamide, a photoinitiator, and water.

[0009] The pregel aqueous solution is applied to the surface of the zinc sheet coated with phytate, and ultraviolet light is used to initiate the formation of a polyanionic gel coating to obtain a zinc anode with phytate-polyanionic gel coating.

[0010] In some embodiments of the present invention, the mass concentration of the phytic acid aqueous solution is 5% to 10%.

[0011] In some embodiments of the present invention, the immersion time in the phytic acid aqueous solution is 1 to 5 minutes.

[0012] In some embodiments of the present invention, after the phytic acid aqueous solution is impregnated, the zinc sheet is washed alternately with ethanol and water, and then dried.

[0013] In some embodiments of the present invention, the photoinitiator includes 2-hydroxy-2-methyl-1-phenyl ketone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,2'-azobisisobutylamidine dihydrochloride, or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

[0014] In some embodiments of the present invention, the molar ratio of acrylamide monomer and sodium 2-acrylamide-2-methylpropanesulfonate monomer is 0.5 to 2:1; in the pregel aqueous solution, the total mass fraction of monomers is 30% to 70%, the mass of N,N'-methylenebisacrylamide accounts for 0.01% to 0.1% of the total mass of monomers, and the mass of photoinitiator accounts for 0.01% to 0.5% of the total mass of monomers.

[0015] In some embodiments of the present invention, the pretreatment refers to polishing the zinc sheet with 2000-grit sandpaper, followed by ultrasonic cleaning with ethanol and drying.

[0016] In some embodiments of the present invention, the ultraviolet light is ultraviolet light of 365-410 nm, and the photoinitiation time is 1-4 h.

[0017] Specifically, the pregel aqueous solution is dropped onto the zinc phytate-coated zinc sheet and compressed and sealed into a glass mold to ensure that the solution covers the surface of the zinc sheet. The mold containing the zinc sheet and the pregel aqueous solution is irradiated with 365-410nm ultraviolet light for 1-4 hours to obtain the zinc phytate-polyanionic gel-coated zinc anode.

[0018] The second objective of this invention is to provide a zinc phytate-polyanion gel-coated zinc anode prepared by the above-described preparation method.

[0019] A third objective of this invention is to provide the application of the above-mentioned zinc phytate-polyanion gel coated zinc anode in the preparation of aqueous zinc-ion batteries.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] To address the shortcomings of inorganic coatings and the practical requirements of high-current, high-capacity cycling in aqueous zinc-ion batteries, this invention introduces organic components into the coating, constructing a "polyanionic gel-inorganic" protective layer with a SEI-like structure. Specifically, this invention utilizes a chemical conversion method to first generate a zinc phytate coating in situ on a zinc sheet, and then form a polyanionic gel layer on the outer side of the zinc phytate coating. The zinc phytate coating and the polyanionic gel layer form hydrogen bonds, promoting a tight bond between the polyanionic gel layer and the zinc phytate, reducing impedance and improving the cycling stability of the zinc anode coating. The outer polyanionic gel layer acts as an adhesive, giving the coating a certain degree of flexibility and improving its stability under high-capacity cycling. Simultaneously, the polyanionic gel in Zn... 2+ The deposition process can effectively promote Zn 2+ Desolvation allows the hydrogel framework to maintain uniform ion flux, preventing excessively high local electric field density and effectively suppressing dendrites and side reactions. The design of an SEI-like organic-inorganic coating provides a new approach for the surface modification of zinc anodes. Attached Figure Description

[0022] Figure 1 As a long-cycle control (1 mA / cm²) of bare zinc and zinc phytate-polyanion gel-coated zinc anode symmetric cells in Example 1 and Example 1, this is a comparison of these cells. 2 ~1mAh / cm 2 ).

[0023] Figure 2 As a long-cycle control (10 mA / cm²) of bare zinc and zinc anode symmetric batteries of Example 1 (Zinc phytate-polyanion gel coated zinc), this is a comparative example. 2 ~5mAh / cm 2 ).

[0024] Figure 3 As a control for the zinc dendrite growth behavior of bare zinc in Example 1 and zinc phytate-coated zinc anode in Example 1 (2mAh / cm²), 2 -150 cycles).

[0025] Figure 4 Comparative Example 1: bare zinc; Example 1: zinc phytate-polyanion gel coated zinc anode full cell control (5A / g).

[0026] Figure 5 Comparative Example 1: bare zinc; Example 1: zinc phytate-polyanion gel coated zinc anode full cell control (10 A / g).

[0027] Figure 6 Comparative Example 2: Zinc phytate-coated zinc sheet (PA@Zn); Comparative Example 3: Polyanion gel-coated zinc anode symmetric battery long-cycle control (1 mA / cm²). 2 ~1mAh / cm 2 ). Detailed Implementation

[0028] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0029] Unless otherwise specified, the experimental and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0030] Aqueous zinc-ion batteries have attracted widespread attention as a novel type of rechargeable battery due to their advantages such as good safety, low cost, and high capacity. However, current research has found that aqueous zinc-ion batteries are prone to dendrite formation on the negative electrode and also suffer from interfacial corrosion, which seriously hinders their application. Current methods to address these issues involve constructing an inorganic coating on the zinc negative electrode surface. This inorganic coating can guide the uniform deposition of zinc ions, playing a positive role in mitigating the problems. However, similar to general inorganic materials, the constructed inorganic coating lacks toughness, especially when used in negative electrode materials. During high-capacity cycling, the negative electrode often undergoes volume changes, which can lead to cracking or even detachment of the poorly tough inorganic coating, preventing the formation of a long-term effective inorganic coating on the negative electrode surface.

[0031] To address the aforementioned problems, this invention, in addition to constructing an inorganic coating on the surface of the negative electrode material, also constructs an organic coating, namely a polyanionic gel layer, on the surface of the inorganic coating, effectively solving the above-mentioned problems.

[0032] In this invention, the inorganic coating is a zinc phytate coating. Phytic acid (PA) is a sustainable organic acid containing 6 phosphate carboxyl groups and 12 hydroxyl groups, possessing inherent metal chelating ability and capable of forming PA-metal complexes. The zinc phytate coating can effectively suppress interfacial side reactions, thereby stabilizing the electrode-electrolyte interface. Utilizing the chelating effect between Zn and PA, a uniform, dense interfacial protective layer with good zinc affinity is formed, promoting uniform zinc metal deposition and effectively inhibiting zinc dendrite growth and negative electrode corrosion.

[0033] Subsequently, a polyanionic gel layer is formed on the outer side of the zinc phytate coating. Hydrogen bonds are formed between the zinc phytate coating and the polyanionic gel layer, promoting a tight bond between the polyanionic gel layer and zinc phytate, reducing impedance and improving the cycling stability of the zinc anode coating. The outer polyanionic gel layer acts as an adhesive, giving the coating a certain degree of flexibility and improving its stability under high-capacity cycling. Simultaneously, the polyanionic gel in Zn... 2+ The deposition process can effectively promote Zn 2+Desolvation allows the hydrogel framework to maintain a uniform ion flux, avoiding excessively high local electric field density and effectively suppressing dendrites and side reactions.

[0034] In this invention, the method for forming the polyanionic gel layer is to use ultraviolet light to initiate the reaction. First, a pregel aqueous solution is prepared by mixing acrylamide, sodium 2-acrylamido-2-methylpropanesulfonate, N,N'-methylenebisacrylamide, a photoinitiator and water. Then, the polymerization reaction is initiated by irradiation with 365-410 nm ultraviolet light.

[0035] In a preferred embodiment of the present invention, the photoinitiator includes 2-hydroxy-2-methyl-1-phenyl ketone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,2'-azobisisobutylamidine dihydrochloride, or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

[0036] In a preferred embodiment of the present invention, the ultraviolet light is ultraviolet light of 365-410 nm, and the photoinitiation time is 1-4 h.

[0037] Specifically, this invention provides a method for preparing a zinc anode coated with zinc phytate-polyanion gel, comprising the following steps:

[0038] S1. Cut the zinc sheet to the appropriate size, polish it with 2000 grit sandpaper, clean it with an appropriate amount of ethanol using ultrasound, and then immerse it in a 5% to 10% phytic acid solution for 1 to 5 minutes. Prepare a zinc phytate coating on the surface of the zinc sheet in situ using a chemical conversion method. Clean the surface of the zinc sheet with ethanol and deionized water to prepare a zinc phytate coating-zinc sheet.

[0039] A pregel aqueous solution was prepared by mixing acrylamide, sodium 2-acrylamido-2-methylpropanesulfonate, N,N'-methylenebisacrylamide, a photoinitiator, and water. The sodium 2-acrylamido-2-methylpropanesulfonate was a 50% (w / w) aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate. The photoinitiator included 2-hydroxy-2-methyl-1-phenyl ketone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,2'-azobisisobutylamidine dihydrochloride, or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

[0040] The molar ratio of acrylamide monomer to sodium 2-acrylamide-2-methylpropanesulfonate monomer is 0.5 to 2:1; in the pregel aqueous solution, the total mass fraction of monomers is 30% to 70%, the mass of N,N'-methylenebisacrylamide accounts for 0.01% to 0.1% of the total mass of monomers, and the mass of photoinitiator accounts for 0.01% to 0.5% of the total mass of monomers.

[0041] S2. The pre-gelled aqueous solution from S1 is applied to the surface of the zinc phytate coating-zinc sheet. Ultraviolet light is used to initiate the formation of a polyanionic gel coating, ultimately yielding a zinc phytate-polyanionic gel-coated zinc anode. Specifically, the pre-gelled aqueous solution is dropped onto the zinc phytate coating-zinc sheet and compressed and sealed into a glass mold, ensuring the solution covers the zinc sheet surface. The mold containing the zinc sheet and the pre-gelled aqueous solution is irradiated with 365–410 nm ultraviolet light for 1–4 hours to obtain the zinc phytate-polyanionic gel-coated zinc anode.

[0042] This invention also provides an aqueous zinc-ion battery, wherein the negative electrode of the battery adopts the zinc phytate-polyanion gel-coated zinc negative electrode prepared in this invention, and the battery assembly method is as follows:

[0043] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0044] The invention will now be described in detail through the following embodiments and comparative examples.

[0045] Example 1

[0046] A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel includes the following steps:

[0047] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0048] (2) Immerse the zinc sheet in a 10% phytic acid aqueous solution for 2 minutes, clean the surface of the zinc sheet with ethanol and deionized water, and dry the zinc sheet in a vacuum drying oven.

[0049] (3) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate (added as a 50% sodium 2-acrylamido-2-methylpropanesulfonate aqueous solution), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0050] (4) Drop the prepared pregel solution onto the zinc sheet treated in step (2) and compress and seal it into a glass mold to ensure that the solution completely covers the surface of the zinc sheet. Irradiate the mold containing the zinc sheet and the pregel solution with 365nm ultraviolet light for 2 hours to obtain the zinc anode with zinc phytate-polyanionic gel coating.

[0051] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0052] Example 2

[0053] A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel includes the following steps:

[0054] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0055] (2) Immerse the zinc sheet in a 10% phytic acid aqueous solution for 2 minutes, clean the surface of the zinc sheet with ethanol and deionized water, and dry the zinc sheet in a vacuum drying oven.

[0056] (3) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate (added as a 50% sodium 2-acrylamido-2-methylpropanesulfonate aqueous solution), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0057] (4) Drop the prepared pregel solution onto the zinc sheet treated in step (2) and compress and seal it into a specific glass mold to ensure that the solution completely covers the surface of the zinc sheet. Irradiate the mold containing the zinc sheet and the pregel solution with 365nm ultraviolet light for 1 hour to obtain the zinc phytate-polyanionic gel coated zinc anode.

[0058] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0059] Example 3

[0060] A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel includes the following steps:

[0061] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0062] (2) Immerse the zinc sheet in a 10% phytic acid aqueous solution for 2 minutes, clean the surface of the zinc sheet with ethanol and deionized water, and dry the zinc sheet in a vacuum drying oven.

[0063] (3) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate (added as a 50% sodium 2-acrylamido-2-methylpropanesulfonate aqueous solution), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0064] (4) The prepared pregel solution is dropped onto the treated zinc sheet and compressed and sealed into a specific glass mold to ensure that the solution completely covers the surface of the zinc sheet. The mold containing the zinc sheet and the pregel solution is irradiated with 365nm ultraviolet light for 4 hours to obtain the zinc phytate-polyanionic gel coated zinc anode.

[0065] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0066] Example 4

[0067] A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel includes the following steps:

[0068] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0069] (2) Immerse the zinc sheet in a 5% phytic acid aqueous solution for 5 minutes, clean the surface of the zinc sheet with ethanol and deionized water, and dry the zinc sheet in a vacuum drying oven.

[0070] (3) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate (added as a 50% aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0071] (4) Drop the prepared pregel solution onto the zinc sheet treated in step (2) and compress and seal it into a specific glass mold to ensure that the solution completely covers the surface of the zinc sheet. Irradiate the mold containing the zinc sheet and the pregel solution with 365nm ultraviolet light for 2 hours to obtain the zinc anode with zinc phytate-polyanionic gel coating.

[0072] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0073] Example 5

[0074] A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel includes the following steps:

[0075] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0076] (2) Immerse the zinc sheet in a 5% phytic acid aqueous solution for 5 minutes, clean the surface of the zinc sheet with ethanol and deionized water, and dry the zinc sheet in a vacuum drying oven.

[0077] (3) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate solution (added as a 50% aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0078] (4) The prepared pregel solution is dropped onto the treated zinc sheet and compressed and sealed into a specific glass mold to ensure that the solution completely covers the surface of the zinc sheet. The mold containing the zinc sheet and the pregel solution is irradiated with 365nm ultraviolet light for 4 hours to obtain the zinc phytate-polyanionic gel coated zinc anode.

[0079] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0080] Example 6

[0081] A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel includes the following steps:

[0082] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0083] (2) Immerse the zinc sheet in a 5% phytic acid aqueous solution for 5 minutes, clean the surface of the zinc sheet with ethanol and deionized water, and dry the zinc sheet in a vacuum drying oven.

[0084] (3) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate solution (added as a 50% sodium 2-acrylamido-2-methylpropanesulfonate aqueous solution), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0085] (4) Drop the prepared pregel solution onto the zinc sheet treated in step (2) and compress and seal it into a specific glass mold to ensure that the solution completely covers the surface of the zinc sheet. Irradiate the mold containing the zinc sheet and the pregel solution with 365nm ultraviolet light for 1 hour to obtain the zinc phytate-polyanionic gel coated zinc anode.

[0086] Following the order of placing the positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring, and negative electrode shell, the battery is finally sealed using a button cell sealing machine at a pressure of 500 psi.

[0087] Comparative Example 1

[0088] Bare zinc sheet, i.e., zinc sheet without zinc phytate-polyanionic gel coating.

[0089] Comparative Example 2

[0090] The preparation of a zinc phytate coating only on zinc sheets includes the following steps:

[0091] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0092] (2) The zinc sheet was immersed in a 10% phytic acid solution for 2 minutes, and the surface of the zinc sheet was cleaned with ethanol and deionized water. The zinc sheet was then dried in a vacuum drying oven to prepare phytic acid zinc coated zinc sheet.

[0093] Comparative Example 3

[0094] The preparation of a polyanionic gel coating on a zinc sheet includes the following steps:

[0095] (1) Cut zinc sheets, polish them with 2000-grit sandpaper, and clean them with ethanol using ultrasonic cleaning.

[0096] (2) Preparation of pregel solution: Dissolve 7.2g of acrylamide, 45.85g of sodium 2-acrylamido-2-methylpropanesulfonate aqueous solution (added in the form of 50% sodium 2-acrylamido-2-methylpropanesulfonate aqueous solution), 0.0143g of N,N'-methylenebisacrylamide, and 0.0224g of 1-hydroxy-cyclohexyl-phenyl ketone in 70ml of deionized water to prepare a pregel solution.

[0097] (3) Drop the prepared pregel solution onto the zinc sheet treated in step (1) and compress and seal it into a glass mold to ensure that the solution completely covers the surface of the zinc sheet. Irradiate the mold containing the zinc sheet and the pregel solution with 365nm ultraviolet light for 2 hours to obtain the polyanionic gel-coated zinc anode.

[0098] First, the negative electrode zinc sheets prepared in the above embodiments and comparative examples were characterized. As mentioned earlier, the negative electrode zinc sheets were assembled into batteries. Specifically, the order of placement was as follows: positive electrode shell, positive electrode sheet, separator, zinc phytate-polyanion gel coated zinc negative electrode, gasket, spring sheet, and negative electrode shell. Finally, the batteries were packaged using a button cell packaging machine at a pressure of 500 psi. The performance of the assembled batteries was then tested, as detailed below:

[0099] Figure 1 As a long-cycle control (1 mA / cm²) of a symmetric battery prepared from bare zinc in Comparative Example 1 and zinc phytate-polyanion gel-coated zinc anode (PA-AMPS) in Example 1. 2 ~1mAh / cm 2 ),Depend on Figure 1 It can be seen that at 1mA / cm 2 ~1mAh / cm 2 Under the test conditions, the zinc phytate-polyanion gel-coated zinc symmetric cell has a longer cycle life (2400h) compared to the bare zinc symmetric cell.

[0100] Figure 6 The symmetric cells prepared for Comparative Example 2 (zinc phytate-coated zinc sheet, PA@Zn) and Comparative Example 3 (polyanionic gel-coated zinc anode, AMPS@Zn) serve as long-cycle controls (1 mA / cm²). 2 ~1mAh / cm 2 ),Depend on Figure 6 It can be seen that at 1mA / cm 2 ~1mAh / cm 2 Under the test conditions, the polarization voltage of the symmetric cell was significantly reduced after modification with zinc phytate; the cycle life of the symmetric cell was increased to 1200h after modification with polyanion gel coating.

[0101] Combination Figure 1 and Figure 6 It was found that modification with zinc phytate and anionic gel coatings alone improved battery performance. When both were combined, the performance was synergistically enhanced, with a cycle life as high as 2400 hours, indicating a strong synergistic effect. The reason for this is that phytate has inherent metal chelating ability, forming PA-metal complexes. The zinc phytate coating effectively suppresses interfacial side reactions, thus stabilizing the electrode-electrolyte interface. The chelation between Zn and PA forms a uniform, dense, and zinc-loving interfacial protective layer, promoting uniform zinc metal deposition, effectively inhibiting zinc dendrite growth and negative electrode corrosion, thereby improving battery performance. Polyanionic gel on Zn... 2+ The deposition process can effectively promote Zn 2+ Desolvation allows the hydrogel framework to maintain a uniform ion flux, avoid excessively high local electric field density, effectively suppress dendrites and side reactions, and thus improve battery performance.

[0102] Additionally, it should be noted that, Figure 1 In the comparison, the lifespan of the bare zinc battery in Comparative Example 1 was approximately 120 hours, the lifespan of the zinc sheet battery in Comparative Example 2 with phytate-coated zinc sheet was approximately 350 hours, the lifespan of the zinc sheet battery in Comparative Example 3 with polyanion gel-coated zinc sheet was 1200 hours, and the cycle life of the symmetric zinc battery with phytate-zinc sheet and polyanion gel coating in Example 1 was 2400 hours. Compared with Comparative Example 1, the improved lifespan of Example 1 is far greater than the sum of the effects of Comparative Examples 2 and 3. This indicates that the effect of simultaneously setting a zinc sheet coating with phytate and a polyanion gel layer is significantly improved compared to setting either a zinc sheet coating with phytate or a polyanion gel layer alone, achieving a synergistic effect (1+1>2). After constructing a polyanion gel layer on the surface of the zinc sheet coating, in addition to each playing its own role, the zinc sheet coating with phytate and the polyanion gel layer can also have a synergistic effect, significantly improving battery performance. Specifically, hydrogen bonds are formed between the zinc sheet coating with phytate and the polyanion gel layer, promoting a tight bond between the polyanion gel layer and the zinc sheet, reducing impedance and improving the cycle stability of the zinc anode coating.

[0103] To demonstrate the modification effect of the coating of the present invention, the following performance characteristics were further characterized:

[0104] Figure 2 As a long-cycle control (10 mA / cm²) of a symmetric battery prepared from bare zinc in Comparative Example 1 and zinc phytate-polyanion gel-coated zinc anode (PA-AMPS) in Example 1. 2 ~5mAh / cm 2 ),Depend on Figure 2 It can be seen that at 10mA / cm 2 ~5mAh / cm 2 Under relatively high current testing conditions, the zinc phytate-polyanion gel coated zinc symmetric cell exhibits a slightly higher polarization voltage compared to the bare zinc symmetric cell, but still maintains a longer cycle life (600 hours).

[0105] Figure 3 Control for zinc dendrite growth behavior (2mAh / cm) 2 -150 cycles) SEM image, from Figure 3 As can be seen, the two images in the upper left and upper right corners show the growth of zinc dendrites in Example 1 at different magnifications, while the two images in the lower left and lower right corners show the growth of zinc dendrites in bare zinc in Comparative Example 1 at different magnifications. It can be seen that after modification with zinc phytate-polyanionic gel coating, dendrite growth is significantly reduced.

[0106] Figure 4 As a full-cell control (5A / g), from Figure 4As can be seen, after matching the positive electrode, the initial capacity of the full cell modified with zinc phytate-polyanionic gel in Example 1 was 233 mAh / g at a current density of 5 A / g, and the capacity remained at 164 mAh / g after 3000 cycles (the capacity of the bare zinc full cell dropped to 69 mAh / g), with a capacity retention rate of 68.7%.

[0107] Figure 5 For the full cell control (10 A / g), from Figure 5 As can be seen, at a current density of 10 A / g, the initial capacity of the full cell modified with zinc phytate-polyanionic gel in Example 1 was 165.8 mAh / g, and after 3000 cycles, the capacity was still maintained at 96.3 mAh / g (the capacity of the bare zinc full cell dropped to 35.5 mAh / g), with a capacity retention rate of 60%.

[0108] The above characterization results all demonstrate that the "polyanionic gel-inorganic" protective layer with a SEI-like structure constructed in this invention can significantly improve the performance of the zinc anode, providing an improvement strategy for the further development of aqueous zinc-ion batteries. The performance of the remaining embodiments is similar to that of Embodiment 1, and will not be described in detail here.

[0109] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A method for preparing a zinc anode coated with zinc phytic acid-polyanion gel, characterized in that, Includes the following steps: Zinc sheets are pretreated and then immersed in phytic acid aqueous solution to prepare phytic acid-coated zinc sheets. A pregel aqueous solution was prepared by mixing acrylamide monomer, sodium 2-acrylamide-2-methylpropanesulfonate monomer, N,N'-methylenebisacrylamide, photoinitiator and water. The pregel aqueous solution is applied to the surface of the zinc sheet coated with phytate, and ultraviolet light is used to initiate the formation of a polyanionic gel coating to obtain a zinc anode with phytate-polyanionic gel coating.

2. The preparation method according to claim 1, characterized in that, The phytic acid aqueous solution has a mass concentration of 5% to 10%.

3. The preparation method according to claim 1, characterized in that, The immersion time in the phytic acid aqueous solution is 1 to 5 minutes.

4. The preparation method according to claim 1, characterized in that, After the phytic acid aqueous solution is impregnated, the zinc sheet is rinsed alternately with ethanol and water, and then dried.

5. The preparation method according to claim 1, characterized in that, The photoinitiator is 2-hydroxy-2-methyl-1-phenyl ketone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,2'-azobisisobutylamidine dihydrochloride, or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

6. The preparation method according to claim 1, characterized in that, The molar ratio of acrylamide monomer to sodium 2-acrylamide-2-methylpropanesulfonate monomer is 0.5 to 2:1; in the pregel aqueous solution, the total mass fraction of monomers is 30% to 70%, the mass of N,N'-methylenebisacrylamide accounts for 0.01% to 0.1% of the total mass of monomers, and the mass of photoinitiator accounts for 0.01% to 0.5% of the total mass of monomers.

7. The preparation method according to claim 1, characterized in that, The ultraviolet light is ultraviolet light of 365-410 nm, and the photoinitiation time is 1-4 h.

8. The preparation method according to claim 1, characterized in that, The pretreatment refers to polishing the zinc sheet with 2000-grit sandpaper, then ultrasonically cleaning it with ethanol, and finally drying it.

9. The zinc phytate-polyanion gel-coated zinc anode prepared by the preparation method according to any one of claims 1-8.

10. The application of the zinc phytate-polyanion gel coated zinc anode according to claim 9 in the preparation of aqueous zinc-ion batteries.

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