Hydrophobic-zinc-philic interface protection layer of high-magnification zinc metal negative electrode as well as preparation and application of hydrophobic-zinc-philic interface protection layer

Abstract

The invention belongs to the technical field of electrochemical batteries, and discloses a hydrophobic-zinc-philic interface protection layer of a high-rate zinc metal negative electrode and preparation and application of the hydrophobic-zinc-philic interface protection layer. The preparation method comprises the following steps: dissolving a polyvinyl alcohol derivative in a polar solvent, uniformly distributing a precursor on the surface of zinc metal through a gradient spin-coating process (including a low-speed pre-coating process and a high-speed spin-coating process), and inducing phase separation by using a specific saturated salt solution. And finally preparing the hydrophobic-zinc-loving interface protection layer of the high-magnification zinc metal negative electrode. According to the hydrophobic-zinc-philic interface protection layer, a hydrophobic long chain is used for inhibiting water-related side reactions, rapid transmission of zinc ions is promoted through a zinc-philic functional group, and then the zinc metal negative electrode and the zinc battery which have excellent rate capability (40mA cm <-2 >) and long cycle stability (2000h) at the same time are achieved. In addition, the preparation process is mild in reaction conditions and simplified in operation steps, has large-scale production potential and has remarkable industrial application prospects.

Description

Technical Field

[0001] This invention patent relates to the technical field of electrochemical cells, and particularly to a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode, and its preparation and application. Background Art

[0002] In recent years, frequent thermal runaway and combustion accidents in traditional organic electrolyte energy storage systems have greatly promoted the research process of aqueous battery systems. Among new aqueous energy storage technologies, zinc metal, with its high theoretical capacity (5855 mAh cm -3 and 820 mAh g -1 ), inherent safety, and cost advantages, makes aqueous zinc-ion batteries using zinc metal as the anode one of the strong candidates for grid-scale energy storage systems. However, the practical application of zinc anodes is still limited by insufficient cycle life and low Coulombic efficiency, and its core failure mechanism stems from: (1) the three-dimensional disordered growth of zinc dendrites leading to the accumulation of "dead zinc" and irreversible loss of active substances; (2) the intense hydrogen evolution reaction (HER) inducing an increase in the local pH value at the electrolyte-electrode interface, triggering the continuous deposition of inert by-products (such as Zn4SO4(OH)6·xH2O, ZSH), which further accelerates the surface passivation process. It is worth noting that there is a significant positive feedback effect between dendrite growth and HER - the enhanced electric field distortion at the dendrite tip will further exacerbate HER, and the insulating properties of by-products exacerbate the uneven distribution of zinc ion deposition sites, ultimately leading to rapid electrode failure.

[0003] Therefore, in response to the complex problems faced by zinc metal anodes, researchers have proposed various strategies (including but not limited to surface modification, electrode design, electrolyte formulation, and separator modification, etc.) to improve the reversibility and cycle life of zinc metal. Among them, the surface modification strategy for zinc metal has been widely studied due to its simplicity and ease of manipulation. For example, the team of Professor Ren Xiaodi at the University of Science and Technology of China [Nat. Commun., 2024, 15, 4303.] constructed a hydrophobic microenvironment interface on the zinc anode surface using a strong acid (bis(trifluoromethanesulfonyl)imide) to inhibit continuous corrosion reactions and promote uniform zinc deposition. And the teams of Professor Zhang Ning at Hebei University and Professor Liu Yongchang at the University of Science and Technology Beijing [Energy Environ. Sci., 2024, 17, 9611.] reported a hydrophobic heterometal-polymer hybrid interface (lead-polyvinylidene fluoride) to prevent side reactions of water at the interface to achieve dendrite-free zinc deposition.

[0004] The above research results show that constructing an interfacial protective layer with hydrophobicity is an effective strategy to improve the electrochemical performance of zinc anodes. However, zinc ions in the electrolyte usually exist as [Zn(H2O)6] 2+The solvation structure exists, that is, water molecules surround the zinc ions. This also results in that although the hydrophobic layer can effectively avoid water-related side reactions, it will simultaneously increase its desolvation energy barrier and inevitably reduce the transport kinetics. Therefore, in order to develop zinc metal anodes and zinc batteries with high rate performance and long-term stability, it is urgent to develop a hydrophobic-zincophilic interfacial protective layer that can effectively repel interfacial water molecules and promote the favorable transport of zinc ions. Summary of the Invention

[0005] To solve the above technical problems, the object of the present invention is to provide a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode, its preparation and application. Dissolve a polyvinyl alcohol derivative in a polar solvent, and then uniformly distribute the precursor on the zinc metal surface through a gradient spin-coating process (including a low-speed pre-coating and a high-speed spin-coating process). Subsequently, use a specific saturated salt solution to induce phase separation, and finally prepare a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode. The protective layer has both hydrophobic long chains and zincophilic functional groups, and through a phase separation process with a specific saturated salt solution, the hydrophobic ability of the interfacial protective layer is easily adjusted to effectively inhibit water molecule-related side reactions. At the same time, the introduction of zincophilic sites can effectively promote the desolvation of zinc ions, thereby accelerating ion transport and reaction kinetics. Finally, zinc metal anodes and zinc batteries with high rate performance and long cycle life can be achieved.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] In the first aspect, the present invention provides a method for preparing a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode, including the following steps:

[0008] (1) Dissolve a polyvinyl alcohol derivative in a polar solvent to obtain a precursor solution;

[0009] (2) Take the precursor solution and drop it onto the surface of the zinc metal. After there are no bubbles remaining on the surface, place it on a spin coater and use a gradient spin-coating process to uniformly spin-coat the precursor on the zinc metal surface;

[0010] (3) Place the spin-coated zinc metal on a saturated salt solution to undergo a phase separation process to obtain a zinc metal anode with a hydrophobic-zincophilic interfacial protective layer.

[0011] Further, in step (1), the polyvinyl alcohol derivative includes at least one of short-chain esterified polyvinyl alcohol, long-chain esterified polyvinyl alcohol, short-chain etherified polyvinyl alcohol, long-chain etherified polyvinyl alcohol, short-chain aminated polyvinyl alcohol, long-chain aminated polyvinyl alcohol, short-chain silylated polyvinyl alcohol, long-chain silylated polyvinyl alcohol, short-chain quaternized polyvinyl alcohol, long-chain quaternized polyvinyl alcohol, short-chain amidated polyvinyl alcohol, and long-chain amidated polyvinyl alcohol.

[0012] Furthermore, the polyvinyl alcohol derivative includes at least one of short-chain aminated polyvinyl alcohol and long-chain aminated polyvinyl alcohol.

[0013] Further, in step (1), the polar solvent includes at least one of water, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, dimethylethoxysilane, tetrahydrofuran, sulfolane, cyclohexanone, ethanol, acetonitrile, pyridine, 1,3-dioxolane, 1,4-dioxane, and ethylene glycol dimethyl ether.

[0014] Furthermore, the polar solvent includes at least one of water, dimethyl sulfoxide, and N,N-dimethylformamide.

[0015] Further, in step (1), the mass fraction of the precursor solution is 2-20%.

[0016] Furthermore, the mass fraction of the precursor solution is 8-10%.

[0017] Further, in step (2), the amount of the precursor solution dropped onto the zinc metal surface is 900-1500 mg, and the coating area of the zinc metal is 20-50 cm 2 .

[0018] Furthermore, the amount of the precursor solution dropped onto the zinc metal surface is 1000-1200 mg, and the coating area of the zinc metal is 30-40 cm 2 .

[0019] Further, in step (2), the gradient spin coating process includes a low-speed pre-coating process and a high-speed spin coating process.

[0020] Further, in step (2), the rotation speed of the low-speed pre-coating process is 100-500 r / min.

[0021] Furthermore, the rotation speed of the low-speed pre-coating process is 200-300 r / min.

[0022] Further, in step (2), the time of the low-speed pre-coating is 5-30 seconds.

[0023] Furthermore, the time of the low-speed pre-coating is 10-15 seconds.

[0024] Further, in step (2), the rotation speed of the high-speed spin coating process is 1000-5000 r / min.

[0025] Furthermore, the rotation speed of the high-speed spin coating process is 2500-3000 r / min.

[0026] Further, in step (2), the time of the high-speed spin coating is 10 - 60 seconds.

[0027] Furthermore, the time of the high-speed spin coating is 20 - 30 seconds.

[0028] Further, in step (3), the solute of the saturated salt solution includes at least one of lithium chloride, lithium bromide, lithium iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, and potassium iodide.

[0029] Furthermore, the solute of the saturated salt solution includes at least one of sodium chloride and potassium iodide.

[0030] Further, in step (3), the solvent of the saturated salt solution includes at least one of water, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoramide, dimethylethoxysilane, tetrahydrofuran, sulfolane, cyclohexanone, acetonitrile, pyridine, 1,3-dioxolane, 1,4-dioxane, and ethylene glycol dimethyl ether.

[0031] Furthermore, the solvent of the saturated salt solution includes at least one of water, dimethyl sulfoxide, and N,N-dimethylformamide.

[0032] Further, in step (3), the time of the phase separation process is 6 - 72 hours.

[0033] Furthermore, the time of the phase separation process is 24 hours.

[0034] In a second aspect, the present invention provides a hydrophobic-zincophilic interface protection layer for a high-rate zinc metal anode prepared by the above preparation method. The protection layer has both hydrophobic long chains and zincophilic functional groups, and through a phase separation process with a specific saturated salt solution, the hydrophobic ability of the interface protection layer is easily adjusted to effectively inhibit side reactions related to water molecules. Meanwhile, the introduction of zincophilic sites can effectively promote the desolvation of zinc ions, thereby accelerating ion transport and reaction kinetics. Finally, a zinc metal anode and a zinc battery with high rate and long cycle life can be achieved.

[0035] In a third aspect, the present invention provides an application of the hydrophobic-zincophilic interface protection layer for the high-rate zinc metal anode in the field of electrochemistry. The application includes the preparation of a symmetric battery and a zinc battery. The preparation method of the symmetric battery is to couple two zinc metal anodes with a hydrophobic-zincophilic interface protection layer to obtain a symmetric battery. The preparation method of the zinc battery is to couple a zinc metal anode with a hydrophobic-zincophilic interface protection layer with a cathode to obtain a zinc battery.

[0036] Further, the thickness of the zinc metal negative electrode is 50 μm - 200 μm.

[0037] Furthermore, the thickness of the zinc metal negative electrode is 100 μm.

[0038] Further, the main substances of the positive electrode include at least one of ammonium vanadate, sodium vanadate, vanadium pentoxide, manganese dioxide, elemental sulfur, elemental selenium, elemental tellurium, elemental iodine, and elemental bromine.

[0039] Furthermore, the main active substance of the positive electrode is sodium vanadate.

[0040] Further, the main substance of the current collector of the positive electrode includes one of carbon felt, carbon paper, graphite paper, stainless steel mesh, copper foil, aluminum foil, and titanium mesh.

[0041] Furthermore, the main substance of the current collector of the positive electrode is stainless steel mesh.

[0042] The beneficial effects that can be produced by this application are as follows:

[0043] (1) The hydrophobic-zincophilic interface protection layer of the high-rate zinc metal negative electrode of the present invention has a structure that simultaneously includes hydrophobic long chains (repelling water molecules at the interface) and zincophilic functional groups (promoting zinc ion transport). This not only significantly inhibits the side reactions caused by interfacial water but also effectively enhances the zinc ion transport kinetics. Based on the above characteristics, this protection layer can achieve uniform, dense, and efficient zinc deposition behavior, and finally obtain a zinc metal negative electrode and a zinc battery with a long cycle life (2000 hours) and excellent rate performance (40 mAcm -2 ).

[0044] (2) The raw materials of the reaction substances involved in the hydrophobic-zincophilic interface protection layer of the present invention are inexpensive, with small usage amounts, and the preparation process is simple and convenient to operate. It can be completed under conventional experimental conditions and has the potential for large-scale production and long-term storage. And this hydrophobic-zincophilic interface protection layer is not only applicable to zinc metal negative electrodes, but it can also be extended to some other metal negative electrode systems, such as: metal foil materials like copper foil, tin foil, antimony foil, magnesium foil, indium foil, titanium foil, nickel foil, chromium foil, aluminum foil, cobalt foil, tantalum foil, etc., and has broad application prospects. Description of the Drawings

[0045] Figure 1 is a scanning electron microscope image of the zinc metal negative electrode prepared in Example 1.

[0046] Figure 2 is a Tafel curve graph of the zinc metal negative electrodes prepared in Comparative Example 1 and Example 1.

[0047] Figure 3It is the linear sweep voltammogram of the zinc metal anode prepared in Comparative Example 1 and Example 1.

[0048] Figure 4 It is the cycling performance graph of the symmetric cells prepared in Comparative Example 1 and Example 1 at a current density of 2 mA cm -2 , with a deposition areal capacity of 1 mAh cm -2 .

[0049] Figure 5 It is the rate cycling curve graph of the symmetric cell prepared in Comparative Example 1.

[0050] Figure 6 It is the rate cycling curve graph of the symmetric cell prepared in Example 1.

[0051] Figure 7 It is the long-term cycling performance graph of the zinc cell prepared in Comparative Example 1 at a current density of 5 A g -1 .

[0052] Figure 8 It is the long-term cycling performance graph of the zinc cell prepared in Example 1 at a current density of 5 A g -1 . Detailed implementation mode

[0053] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0054] Example 1

[0055] A preparation method for a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, and the detailed steps of this method are as follows:

[0056] (1) Weigh 0.193 mol of polyvinyl alcohol, add 4.49 mol of dimethyl sulfoxide, heat and wait for it to be stirred evenly, then add an activator (such as N,N-carbonyldiimidazole, glutaraldehyde, N-hydroxysuccinimide, (3-aminopropyl)triethoxysilane, etc. are all acceptable) according to a molar ratio of 1.12:1. After it is fully activated, add octylamine (long-chain amine group) according to a molar ratio of 1.25:1. After it fully reacts, add commercial ammonia water (concentration > 25%) according to a molar ratio of 0.36:1. After stirring overnight, raise the temperature to 40 °C and drop in a small amount (about 50 - 100 μL) of hydrochloric acid solution diluted multiple times (pH about 5 - 6), and finally use ultrapure water for centrifugation multiple times and perform freeze-drying for 48 hours to obtain long-chain aminated polyvinyl alcohol;

[0057] (2) Take 600 mg of the long-chain aminated polyvinyl alcohol from step (1), add 5741.15 mg of N,N-dimethylformamide to it. After stirring evenly, a precursor solution with a mass fraction of 9.462% can be obtained.

[0058] (3) Take 1056.86 mg of the precursor solution from step (2), and slowly drop it onto the surface of a 6 cm × 6 cm zinc foil with a thickness of 100 μm. After there are no bubbles on its surface, transfer it into a spin coater for spin coating. First, perform a pre-coating at a low rotation speed of 200 r / min for 10 s, and then spin coat at a high rotation speed of 3000 r / min for 20 s to ensure that the precursor is evenly coated on the surface of the zinc foil. Then place the spin-coated zinc foil on a saturated sodium chloride aqueous solution and let it undergo phase separation for 24 h to obtain a zinc metal negative electrode with a hydrophobic-zincophilic interface protection layer.

[0059] After coupling two zinc metal negative electrodes with a hydrophobic-zincophilic interface protection layer from step (3) with 2 mol / L zinc sulfate (electrolyte) and Whatman glass fiber (separator) in a 2032 button battery, a symmetric battery of Example 1 is obtained; after coupling one zinc metal negative electrode with a hydrophobic-zincophilic interface protection layer from step (3) and one sodium vanadate positive electrode plate with 2 mol / L zinc sulfate (electrolyte) and Whatman glass fiber (separator) in a 2032 button battery, a zinc battery of Example 1 is obtained.

[0060] Comparative Example 1

[0061] A preparation method for a hydrophobic-zincophilic interface protection layer of a high-rate zinc metal negative electrode. The main differences between this method and that of Example 1 are as follows: [[ID=|15]]

[0062] In step (3), the spin-coated zinc foil is directly placed in a vacuum oven. After drying it overnight, the zinc metal negative electrode of this comparative example can be obtained.

[0063] The remaining steps and the experimental parameters involved are the same as those in Example 1.

[0064] Example 2

[0065] A preparation method for a hydrophobic-zincophilic interface protection layer of a high-rate zinc metal negative electrode. The main differences between this method and that of Example 1 are as follows:

[0066] In step (2), 600 mg of long-chain aminated polyvinyl alcohol is added to 6573.6 mg of dimethyl sulfoxide to obtain a precursor solution that can be used to prepare a hydrophobic-zincophilic interface protection layer.

[0067] In step (3), 1195.6 mg of the precursor solution from step (2) was slowly dropped onto the surface of the zinc foil.

[0068] The remaining steps and the experimental parameters involved are the same as those in Example 1.

[0069] Comparative Example 2

[0070] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and Example 2 are as follows:

[0071] In step (3), the spin-coated zinc foil was directly placed in a vacuum oven. After drying overnight, the zinc metal anode of this comparative example was obtained.

[0072] The remaining steps and the experimental parameters involved are the same as those in Example 2.

[0073] Example 3

[0074] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and Example 1 are as follows:

[0075] In step (1), propylamine (short-chain amino group) was added to the fully activated polyvinyl alcohol solution at a molar ratio of 1:0.8 to obtain short-chain aminated polyvinyl alcohol.

[0076] The remaining steps and the experimental parameters involved are the same as those in Example 1.

[0077] Comparative Example 3

[0078] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and Example 3 are as follows:

[0079] In step (3), the spin-coated zinc foil was directly placed in a vacuum oven. After drying overnight, the zinc metal anode of this comparative example was obtained.

[0080] The remaining steps and the experimental parameters involved are the same as those in Example 3.

[0081] Example 4

[0082] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and Example 1 are as follows:

[0083] In step (1), propylamine (short-chain amino group) was added to the fully activated polyvinyl alcohol solution at a molar ratio of 1:0.8 to obtain short-chain aminated polyvinyl alcohol.

[0084] In step (2), 600 mg of short-chain aminated polyvinyl alcohol was added to 6573.6 mg of dimethyl sulfoxide to obtain a precursor solution that can be used to prepare a hydrophobic-zincophilic interface protective layer.

[0085] In step (3), 1195.6 mg of the precursor solution from step (2) was taken.

[0086] The remaining steps and the experimental parameters involved are the same as those in Example 1.

[0087] Comparative Example 4

[0088] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode, and the main differences between this method and Example 4 are as follows:

[0089] In step (3), the zinc foil with the precursor solution was placed in a vacuum oven. After drying overnight, the zinc metal anode of this comparative example can be obtained.

[0090] The remaining steps and the experimental parameters involved are the same as those in Example 4.

[0091] Comparative Example 5

[0092] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode, and the main differences between this method and Example 1 are as follows:

[0093] There is no need to perform additional treatment on polyvinyl alcohol in step (1). In step (2), 600 mg of polyvinyl alcohol was added to 6573.6 mg of dimethyl sulfoxide to obtain a precursor solution that can be used to prepare a hydrophobic-zincophilic interface protective layer.

[0094] In step (3), 1195.6 mg of the precursor solution from step (2) was taken.

[0095] The remaining steps and the experimental parameters involved are the same as those in Example 1.

[0096] Comparative Example 6

[0097] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode, and the main differences between this method and Example 1 are as follows:

[0098] There is no need to perform additional treatment on polyvinyl alcohol in step (1). In step (2), 600 mg of polyvinyl alcohol was added to 6573.6 mg of dimethyl sulfoxide to obtain a precursor solution that can be used to prepare a hydrophobic-zincophilic interface protective layer.

[0099] In step (3), 1195.6 mg of the precursor solution from step (2) was taken. In step (3), the zinc foil with the precursor solution was placed in a vacuum oven. After drying overnight, the zinc metal anode of this comparative example was obtained.

[0100] The remaining steps and the experimental parameters involved were the same as those in Example 1.

[0101] Comparative Example 7

[0102] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and that of Example 1 are as follows:

[0103] There was no need to perform additional treatment on polyvinyl alcohol in step (1). In step (2), 600 mg of polyvinyl alcohol was added to 5982.2 mg of ultrapure water to obtain a precursor solution that can be used to prepare the hydrophobic-zincophilic interface protective layer.

[0104] In step (3), 1097.1 mg of the precursor solution from step (2) was taken. In step (3), the zinc foil with the precursor solution was placed on a saturated potassium iodide (dimethyl sulfoxide) solution to complete the phase separation process, so as to obtain the zinc metal anode of this comparative example.

[0105] The remaining steps and the experimental parameters involved were the same as those in Example 1.

[0106] Comparative Example 8

[0107] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and that of Example 1 are as follows:

[0108] There was no need to perform additional treatment on polyvinyl alcohol in step (1). In step (2), 600 mg of polyvinyl alcohol was added to 5982.2 mg of ultrapure water to obtain a precursor solution that can be used to prepare the hydrophobic-zincophilic interface protective layer.

[0109] In step (3), 1097.1 mg of the precursor solution from step (2) was taken. In step (3), the zinc foil with the precursor solution was placed on a saturated potassium iodide (N,N-dimethylformamide) solution to complete the phase separation process, so as to obtain the zinc metal anode of this comparative example.

[0110] The remaining steps and the experimental parameters involved were the same as those in Example 1.

[0111] Comparative Example 9

[0112] A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal anode. The main differences between this method and that of Example 1 are as follows:

[0113] There is no need to perform additional treatment on polyvinyl alcohol in step (1). In step (2), 600 mg of polyvinyl alcohol is added to 5982.2 mg of ultrapure water to obtain a precursor solution that can be used to prepare a hydrophobic-zincophilic interfacial protective layer.

[0114] In step (3), 1097.1 mg of the precursor solution from step (2) is taken. In step (3), the spin-coated zinc foil is directly placed in a vacuum oven and dried overnight to obtain the zinc metal negative electrode of this comparative example.

[0115] The remaining steps and the experimental parameters involved are the same as those in Example 1.

[0116] Comparative Example 10

[0117] In this comparative example, after simply wiping the surface of the pure zinc foil with ultrapure water and absolute ethanol, the zinc metal negative electrode of this comparative example can be obtained.

[0118] Two zinc metal negative electrodes of this comparative example, 2 mol / L zinc sulfate (electrolyte), and Whatman glass fiber (separator) are jointly placed in a 2032 button battery for coupling to obtain the symmetric battery of Comparative Example 10; one zinc metal negative electrode and one sodium vanadate positive electrode sheet of this comparative example are jointly placed in a 2032 button battery for coupling with 2 mol / L zinc sulfate (electrolyte) and Whatman glass fiber (separator) to obtain the zinc battery of Comparative Example 10.

[0119] Figure 1 It is the scanning electron microscope image of the zinc metal negative electrode prepared in Example 1. The results show that the hydrophobic-zincophilic interfacial protective layer has been successfully and uniformly prepared on the surface of the zinc metal negative electrode. Its morphology presents an ordered and regular texture structure, and this microscopic morphological feature can further enhance its inherent hydrophobic property of the long chain.

[0120] Figure 2 It is the Tafel curve graph of the zinc metal negative electrodes prepared in Comparative Example 10 and Example 1 under a three-electrode system with a scanning rate of 1 mVs -1 below. As Figure 2 shown, the corrosion potential of Example 1 is significantly better than that of Comparative Example 10 (-977.9 mV vs. -986.1 mV), and at the same time, its corresponding corrosion current is lower. This result confirms that the introduction of the hydrophobic-zincophilic interfacial protective layer can effectively inhibit the corrosion reaction induced by water / protons and significantly reduce the corrosion rate, thereby significantly improving the corrosion resistance of the zinc metal negative electrode.

[0121] Figure 3 It is the zinc metal negative electrodes prepared in Comparative Example 10 and Example 1 under a three-electrode system with a scanning rate of 1 mVs -1Linear sweep voltammogram under. It can be seen from Figure 3 that the hydrogen evolution overpotential of Example 1 is significantly lower than that of Comparative Example 10, and at the same response current density (10 mA cm -2 ), it exhibits a more positive corresponding potential (-1.209 V vs. -1.112 V). This phenomenon fully confirms that the hydrophobic-zincophilic interfacial protective layer can effectively reduce the content and reactivity of water molecules at the electrode interface, thereby significantly inhibiting the occurrence of hydrogen evolution side reactions.

[0122] Figure 4 shows the cycling performance of the symmetric cells prepared in Comparative Example 10 and Example 1 at a current density of 2 mA cm -2 , with a deposition areal capacity of 1 mAh cm -2 . As Figure 4 shown, after the zinc metal anode in Comparative Example 10 only undergoes stable cycling for less than 80 hours, the polarization voltage begins to fluctuate frequently, indicating that serious zinc dendrite growth, by-product accumulation, and intense hydrogen evolution side reactions occur during the deposition / stripping process, making it difficult to achieve high-stability cycling. In contrast, in Example 1, the zinc metal anode with the hydrophobic-zincophilic interfacial protective layer exhibits excellent cycling stability and can operate stably for 2000 hours. This fully proves that the hydrophobic-zincophilic interfacial protective layer can significantly improve the reversibility of zinc deposition / stripping and inhibit the occurrence of side reactions.

[0123] Figure 5 and Figure 6 are the rate cycling curves of the symmetric cells prepared in Comparative Example 10 and Example 1 respectively. It can be seen from Figure 5 that when the zinc metal anode in Comparative Example 10 is cycled, as the current density increases, the polarization of the battery will increase rapidly and fluctuate violently and fail quickly after 10 mA cm- 2 , indicating poor interfacial stability. While the zinc metal anode with the hydrophobic-zincophilic interfacial protective layer in Example 1 exhibits excellent rate performance and can still operate stably even at a high current density of 40 mA cm -2 ( Figure 6 ). It should be noted that when the current drops back to 1 mA cm -2 , the battery can still restore stable deposition / stripping behavior, confirming the high structural stability of the protective layer under extreme current conditions. And the zincophilic sites of the hydrophobic-zincophilic interfacial protective layer can promote uniform zinc ion deposition, while the hydrophobic layer can effectively inhibit water-related side reactions, thus enabling stable zinc deposition / stripping behavior at high current densities.

[0124] Figure 7 and Figure 8They are the long-term cycling performance diagrams of the zinc batteries prepared in Comparative Example 10 and Example 1 at a current density of 5 A g -1 It can be clearly seen that the zinc battery in Example 1 can provide a reversible specific capacity of about 170 mAh g -1 at a high current density of 5 A g -1 and can sustain 1500 high-reversibility cycles, with a capacity retention rate as high as 92%. However, for the zinc battery in Comparative Example 10, not only is the capacity it can provide lower during the cycling process (about 155 mAh g -1 ), but the battery also degrades rapidly during cycling. After only 1000 cycles, the capacity retention rate is less than 40%. This indicates that the zinc battery in Example 1 not only has excellent cycle life and fast zinc ion transport kinetics but also has extremely high reversibility of zinc deposition / stripping.

[0125] The contact angles of the zinc metal anodes prepared in Examples 1-4 and Comparative Examples 1-10 were measured, and the results are shown in Table 1.

[0126] Table 1

[0127] Contact angle of ultrapure water (°) Example 1 121.2 Comparative Example 1 107.5 Example 2 119.7 Comparative Example 2 105.9 Example 3 103.1 Comparative Example 3 93.8 Example 4 101.9 Comparative Example 4 92.7 Comparative Example 5 66.8 Comparative Example 6 80.9 Comparative Example 7 70.1 Comparative Example 8 68.2 Comparative Example 9 81.2 Comparative Example 10 89.2

[0128] As can be seen from Table 1, the contact angles of Example 1, Comparative Example 1, Example 2, Comparative Example 2, Example 3, Comparative Example 3, Example 4, and Comparative Example 4 are all higher than that of Comparative Example 10, indicating that the interfacial protective layer with hydrophobic chains introduced can effectively isolate the water molecules at the interface from reacting with the zinc metal anode. Among them, the contact angle of Example 1 is the largest, indicating that the improvement of the hydrophobic effect in this example is the most obvious.

[0129] The polarization voltages of the symmetric batteries prepared in Examples 1-4 and Comparative Examples 1-10 were measured at a current density of 5 mA cm -2 , and the results are shown in Table 2.

[0130] Table 2

[0131]

[0132]

[0133] As can be seen from Table 2, the polarization voltages of Example 1, Comparative Example 1, Example 2, Comparative Example 2, Example 3, Comparative Example 3, Example 4, and Comparative Example 4 are all lower than that of Comparative Example 10, indicating that the interfacial protective layer with zincophilic groups introduced can effectively accelerate the zinc ion transport kinetics and reduce the polarization voltage. Among them, the polarization voltage of Example 1 is the smallest, indicating that the improvement of the zincophilic effect in this example is the most obvious.

[0134] The above is a specific description of the preferred embodiment of the present invention. However, the present invention is not limited to the described embodiment. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal negative electrode, characterized in that: It includes the following steps: (1) Dissolve the polyvinyl alcohol derivative in a polar solvent to obtain a precursor solution; (2) Take the precursor solution and drop it onto the surface of zinc metal. After there are no bubbles remaining on the surface, place it on a spin coater and use a gradient spin coating process to uniformly spin coat the precursor on the surface of zinc metal; (3) Place the spin-coated zinc metal on a saturated salt solution to undergo a phase separation process to obtain a zinc metal negative electrode with a hydrophobic-zincophilic interface protection layer.

2. The preparation method of the hydrophobic-zincophilic interfacial protective layer of the high-rate zinc metal anode according to claim 1, characterized in that In step (1), the polyvinyl alcohol derivative includes at least one of short-chain esterified polyvinyl alcohol, long-chain esterified polyvinyl alcohol, short-chain etherified polyvinyl alcohol, long-chain etherified polyvinyl alcohol, short-chain aminated polyvinyl alcohol, long-chain aminated polyvinyl alcohol, short-chain silylated polyvinyl alcohol, long-chain silylated polyvinyl alcohol, short-chain quaternized polyvinyl alcohol, long-chain quaternized polyvinyl alcohol, short-chain amidated polyvinyl alcohol, and long-chain amidated polyvinyl alcohol.

3. The method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal negative electrode according to claim 1, characterized in that: In step (1), the polar solvent includes at least one of water, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, dimethylethoxysilane, tetrahydrofuran, sulfolane, cyclohexanone, ethanol, acetonitrile, pyridine, 1,3-dioxolane, 1,4-dioxane, and ethylene glycol dimethyl ether.

4. The method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal negative electrode according to claim 1, wherein: In step (1), the mass fraction of the precursor solution is 2-20%.

5. The preparation method of the hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode according to claim 1, characterized in that, In step (2), the gradient spin coating process includes a low-speed pre-coating process and a high-speed spin coating process.

6. The preparation method of the hydrophobic-zincophilic interface protection layer of a high-rate zinc metal negative electrode according to claim 5, wherein, In step (2), the rotation speed of the low-speed pre-coating process is 100-500 r / min, and the time of the low-speed pre-coating is 5-30 seconds.

7. The method for preparing a hydrophobic-zincophilic interface protective layer for a high-rate zinc metal negative electrode according to claim 5, characterized in that: In step (2), the rotation speed of the high-speed spin coating process is 1000-5000 r / min, and the time of the high-speed spin coating is 10-60 seconds.

8. The preparation method of the hydrophobic-zincophilic interface protection layer of a high-rate zinc metal negative electrode according to claim 1, wherein In step (3), the solute of the saturated salt solution includes at least one of lithium chloride, lithium bromide, lithium iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, and potassium iodide, and the solvent of the saturated salt solution includes at least one of water, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, dimethylethoxysilane, tetrahydrofuran, sulfolane, cyclohexanone, acetonitrile, pyridine, 1,3-dioxolane, 1,4-dioxane, and ethylene glycol dimethyl ether; the time of the phase separation process is 6-72 hours.

9. A hydrophobic-zincophilic interface protection layer of a high-rate zinc metal negative electrode prepared by the preparation method according to any one of claims 1-8.

10. Application of the hydrophobic-zincophilic interfacial protective layer of the high-rate zinc metal anode as described in claim 9 in the field of electrochemistry, characterized in that, The application includes the preparation of a symmetric battery and a zinc battery. The preparation method of the symmetric battery is to couple two zinc metal negative electrodes with a hydrophobic-zincophilic interface protection layer to obtain a symmetric battery. The preparation method of the zinc battery is to couple a zinc metal negative electrode with a hydrophobic-zincophilic interface protection layer with a positive electrode to obtain a zinc battery.

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