Hydrophobic-zincophilic interface protective layer of high-rate zinc metal negative electrode and preparation and application thereof

Abstract

The application belongs to the technical field of electrochemical cells, and discloses a hydrophobic-zincophilic interface protective layer of a high-rate zinc metal negative electrode and preparation and application thereof. A polyvinyl alcohol derivative is dissolved in a polar solvent, then the precursor is uniformly distributed on the surface of zinc metal through a gradient spin coating process (including a low-speed pre-coating and a high-speed spin coating process), and then a specific saturated salt solution is used to induce the occurrence of phase separation, so that the hydrophobic-zincophilic interface protective layer of the high-rate zinc metal negative electrode is finally prepared. The hydrophobic-zincophilic interface protective layer of the application uses a hydrophobic long chain to inhibit water-related side reactions, and uses a zincophilic functional group to promote the rapid transmission of zinc ions, so that a zinc metal negative electrode and a zinc battery with excellent rate performance (40 mA cm ‑2 ) and long cycle stability (2000 h) are realized at the same time. In addition, the preparation process has mild reaction conditions, simplified operation steps, and has the potential for large-scale production, and has a significant industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical cells, and particularly relates to a hydrophobic-zincophilic interface protective layer of a high-rate zinc metal negative electrode and preparation and application thereof. BACKGROUND

[0002] In recent years, the frequent thermal runaway and combustion accidents of traditional organic electrolyte energy storage systems have greatly promoted the research process of aqueous battery systems. Among new types of aqueous energy storage technologies, zinc metal has bright advantages in terms of high theoretical capacity (5855 mAh cm -3 and 820 mAh g -1 ), intrinsic safety and cost, making aqueous zinc ion batteries using zinc metal as the negative electrode one of the strong candidates for grid-level energy storage systems. However, the practical application of zinc negative electrodes is still limited by insufficient cycle life and low coulombic efficiency, and the core failure mechanism is as follows: (1) three-dimensional disordered growth of zinc dendrites leads to accumulation of "dead zinc" and irreversible loss of active material; (2) the local pH value of the electrolyte-electrode interface is increased by the severe hydrogen evolution reaction (HER), which induces the continuous deposition of inert by-products (such as Zn4SO4(OH)6·xH2O, ZSH), and 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, while the insulating nature of the by-products will exacerbate the uneven distribution of zinc ion deposition sites, ultimately leading to rapid failure of the electrode.

[0003] To this end, researchers have proposed various strategies (including but not limited to surface modification, electrode design, electrolyte compounding and separator modification, etc.) to improve the reversibility and cycle life of zinc metal in response to the complex problems faced by zinc metal negative electrodes. Among them, the strategy of surface modification of zinc metal is widely studied due to its simplicity and ease of manipulation. For example, Professor Ren Xiaodi's team at the University of Science and Technology of China [Nat. Commun., 2024, 15, 4303.] used a strong acid (bis(trifluoromethylsulfonyl) imide) to construct a hydrophobic microenvironment interface on the surface of the zinc negative electrode to inhibit continuous corrosion reactions and promote uniform zinc deposition. Professor Zhang Ning's team at Hebei University and Professor Liu Yongxiang's team at Beijing University of Science and Technology [Energy Environ. Sci., 2024, 17, 9611.] reported a hydrophobic hetero-metal-polymer hybrid interface (lead-polyvinylidene fluoride) to prevent water from reacting at the interface, achieving dendrite-free zinc deposition.

[0004] The above research results show that constructing a hydrophobic interface protective layer is an effective strategy to improve the electrochemical performance of zinc negative electrodes. However, zinc ions in the electrolyte are usually in the form of [Zn(H2O)6] 2+The solvation structure exists, that is, the zinc ion outside will surround / encircle the water molecules. This also leads to, although the hydrophobic layer can effectively avoid water-related side reactions, it will also increase its desolvation energy barrier at the same time and inevitably reduce the transmission kinetics. Therefore, in order to develop a zinc metal negative electrode and a zinc battery with high rate and long-term stability, it is urgent to develop a hydrophobic-zincophilic interface protective layer that can effectively repel interfacial water molecules and promote the beneficial transmission of zinc ions. SUMMARY

[0005] In order to solve the above technical problems, the purpose of the present application is to provide a hydrophobic-zincophilic interface protective layer for high-rate zinc metal negative electrode and its preparation and application. A polyvinyl alcohol derivative is dissolved in a polar solvent, and then the precursor is uniformly distributed on the surface of zinc metal by gradient spin coating process (including low-speed pre-coating and high-speed spin coating process), and then a specific saturated salt solution is used to induce the occurrence of phase separation, and finally a hydrophobic-zincophilic interface protective layer for high-rate zinc metal negative electrode is prepared. The protective layer has both hydrophobic long chains and zincophilic functional groups, and the phase separation process is carried out by a specific saturated salt solution, which easily adjusts the hydrophobicity of the interface protective layer to effectively inhibit the water molecule related side reactions. At the same time, the introduction of zincophilic sites can effectively promote the desolvation of zinc ions, thereby accelerating the ion transmission and reaction kinetics. Finally, a zinc metal negative electrode and a zinc battery with high rate and long cycle life can be realized.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] In a first aspect, the present application provides a preparation method of a hydrophobic-zincophilic interface protective layer for high-rate zinc metal negative electrode, comprising 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 zinc metal. After there is no any bubble residue 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;

[0010] (3) Place the spin-coated zinc metal in a saturated salt solution to undergo a phase separation process, and obtain a zinc metal negative electrode with a hydrophobic-zincophilic interface 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 silanized polyvinyl alcohol, long-chain silanized polyvinyl alcohol, short-chain quaternized polyvinyl alcohol, long-chain quaternized polyvinyl alcohol, short-chain amide polyvinyl alcohol, and long-chain amide polyvinyl alcohol.

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

[0013] Further, in the 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] Further, the polar solvent includes at least one of water, dimethyl sulfoxide, and N,N-dimethylformamide.

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

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

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

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

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

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

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

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

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

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

[0025] Further, 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] Further, in step (2), the time of the high-speed spin coating is 10-60 seconds.

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

[0029] Further, in step (3), the solute of the saturated salt solution comprises at least one of lithium chloride, lithium bromide, lithium iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide.

[0030] Further, in step (3), the solvent of the saturated salt solution comprises 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, ethylene glycol dimethyl ether.

[0031] Further, in step (3), the solvent of the saturated salt solution comprises 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, ethylene glycol dimethyl ether.

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

[0033] Further, in step (3), the time of the phase separation process is 6-72 hours.

[0034] In a second aspect, the present application provides a hydrophobic-zincophilic interfacial protective layer of the high-rate zinc metal anode prepared by the preparation method described above, which has both a long-chain hydrophobic group and a zincophilic functional group, and is prepared by a phase separation process with a specific saturated salt solution, so as to easily adjust the hydrophobicity of the interfacial protective layer to effectively inhibit the water molecule related side reactions. At the same time, the introduction of zincophilic sites can effectively promote the desolvation of zinc ions, thereby accelerating the ion transport and reaction kinetics. Finally, a zinc metal anode and a zinc battery with high rate and long cycle life can be realized.

[0035] In a third aspect, the present application provides an application of the hydrophobic-zincophilic interfacial protective layer of the high-rate zinc metal anode described above in the field of electrochemistry, which 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 hydrophobic-zincophilic interfacial protective layers to obtain a symmetric battery. The preparation method of the zinc battery is to couple a zinc metal anode with a hydrophobic-zincophilic interfacial protective layer with a positive electrode to obtain a zinc battery.

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

[0037] Further, the thickness of the zinc metal negative electrode is 50-200 μm.

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

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

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

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

[0042] The application can produce the following beneficial effects:

[0043] (1) The hydrophobic-zincophilic interface protective layer of the high-rate zinc metal negative electrode of the application comprises hydrophobic long chains (repelling water molecules at the interface) and zincophilic functional groups (promoting zinc ion transmission) at the same time. This not only significantly inhibits the side reactions caused by the interface water, but also effectively enhances the zinc ion transmission kinetics. Based on the above characteristics, the protective layer can realize uniform, dense and efficient zinc deposition behavior, and finally obtain a zinc metal negative electrode and a zinc battery with long cycle life (2000 hours) and excellent rate performance (40 mA cm -2 ).

[0044] (2) The reactant of the hydrophobic-zincophilic interface protective layer of the application has low raw material price, small amount, simple preparation process and convenient operation, which can be completed under conventional experimental conditions, and has the potential for large-scale production and long-term storage. Moreover, the hydrophobic-zincophilic interface protective layer is not only suitable for zinc metal negative electrode, but also can be extended to some other metal negative electrode systems, such as: copper foil, tin foil, antimony foil, magnesium foil, indium foil, titanium foil, nickel foil, chromium foil, aluminum foil, cobalt foil, tantalum foil and other metal foil materials, which has broad application prospects. BRIEF DESCRIPTION OF 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 diagram of the zinc metal negative electrode prepared in Comparative Example 1 and Example 1.

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

[0048] Figure 4 is a cycle performance graph of the symmetric battery prepared in Comparative Example 1 and Example 1 at a current density of 2 mA cm -2 , and a deposition surface capacity of 1 mAh cm -2 .

[0049] Figure 5 is a rate cycle graph of the symmetric battery prepared in Comparative Example 1.

[0050] Figure 6 is a rate cycle graph of the symmetric battery prepared in Example 1.

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

[0052] Figure 8 is a long cycle performance graph of the zinc battery prepared in Example 1 at a current density of 5 A g -1 . DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only 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 labor fall within the scope of the present application.

[0054] Example 1

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

[0056] (1) 0.193 mol of polyvinyl alcohol is weighed, 4.49 mol of dimethyl sulfoxide is added, heated and stirred until uniform, then an activator (such as N,N-carbonyldiimidazole, glutaraldehyde, N-hydroxysuccinimide, (3-aminopropyl)triethoxysilane, etc.) is added in a molar ratio of 1.12:1, and after being fully activated, octylamine (long-chain amine group) is added in a molar ratio of 1.25:1, and after being fully reacted, commercial ammonia water (concentration > 25%) is added in a molar ratio of 0.36:1, and after stirring overnight, the temperature is raised to 40°C and a small amount (about 50-100 μL) of diluted hydrochloric acid solution (PH about 5-6) is added dropwise, and finally ultra-pure water is used for multiple centrifugation and 48 hours of freeze-drying, to obtain long-chain amine-modified polyvinyl alcohol;

[0057] (2) Take 600 mg of long-chain aminated polyvinyl alcohol of step (1), add 5741.15 mg of N,N-dimethylformamide thereto, and after stirring uniformly, a precursor solution with a mass fraction of 9.462% is obtained;

[0058] (3) Take 1056.86 mg of the precursor solution of step (2), slowly drop it onto the surface of a 6 cm x 6 cm zinc foil with a thickness of 100 μm, and after there are no bubbles on the surface, transfer it to a spin coater for spin coating; first, pre-coat at a low speed of 200 r / min for 10 s, and then spin coat at a high speed of 3000 r / min for 20 s to ensure that the precursor is uniformly coated on the surface of the zinc foil; then, place the spin-coated zinc foil on a saturated sodium chloride aqueous solution and allow it to continue phase separation for 24 h, thereby obtaining a zinc metal negative electrode with a hydrophobic-zincophilic interfacial protection layer.

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

[0060] Comparative Example 1

[0061] A method for preparing a hydrophobic-zincophilic interfacial protection layer of a high-rate zinc metal negative electrode, which mainly differs from Example 1 as follows:

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

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

[0064] Example 2

[0065] A method for preparing a hydrophobic-zincophilic interfacial protection layer of a high-rate zinc metal negative electrode, which mainly differs from Example 1 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 interfacial protection layer.

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

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

[0069] Comparative Example 2

[0070] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 2 as follows:

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

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

[0073] Example 3

[0074] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

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

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

[0077] Comparative Example 3

[0078] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 3 as follows:

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

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

[0081] Example 4

[0082] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

[0083] In step (1), propylamine (a short-chain amine group) was added to the fully activated polyvinyl alcohol solution in a molar ratio of 1:0.8 to obtain a short-chain amine-modified 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 the hydrophobic-zincophilic interfacial protective layer.

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

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

[0087] Comparative Example 4

[0088] A method for preparing a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode, which mainly differs from Example 4 as follows:

[0089] In step (3), the zinc foil with the precursor solution was placed in a vacuum oven, and after it was dried overnight, the zinc metal anode of this comparative example was obtained.

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

[0091] Comparative Example 5

[0092] A method for preparing a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

[0093] No additional treatment of the polyvinyl alcohol was performed 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 the hydrophobic-zincophilic interfacial protective layer.

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

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

[0096] Comparative Example 6

[0097] A method for preparing a hydrophobic-zincophilic interfacial protective layer for a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

[0098] No additional treatment of the polyvinyl alcohol was performed 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 the hydrophobic-zincophilic interfacial protective layer.

[0099] Step (3) is to take 1195.6 mg of the precursor solution of step (2). Step (3) is to place the zinc foil with the precursor solution into a vacuum oven, and after it is dried overnight, the zinc metal anode of this comparative example is obtained.

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

[0101] Comparative Example 7

[0102] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

[0103] No additional treatment of the polyvinyl alcohol in step (1) is needed. Step (2) is to add 600 mg of polyvinyl alcohol to 5982.2 mg of ultrapure water to obtain a precursor solution that can be used to prepare the hydrophobic-zincophilic interfacial protective layer.

[0104] Step (3) is to take 1097.1 mg of the precursor solution of step (2). Step (3) is to place the zinc foil with the precursor solution into 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 are the same as in Example 1.

[0106] Comparative Example 8

[0107] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

[0108] No additional treatment of the polyvinyl alcohol in step (1) is needed. Step (2) is to add 600 mg of polyvinyl alcohol to 5982.2 mg of ultrapure water to obtain a precursor solution that can be used to prepare the hydrophobic-zincophilic interfacial protective layer.

[0109] Step (3) is to take 1097.1 mg of the precursor solution of step (2). Step (3) is to place the zinc foil with the precursor solution into 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.

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

[0111] Comparative Example 9

[0112] A method for preparing a hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal anode, which mainly differs from Example 1 as follows:

[0113] No additional treatment of polyvinyl alcohol in Step (1) is needed. 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 the 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 after it is dried overnight, the zinc metal anode of this comparative example is obtained.

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

[0116] Comparative Example 10

[0117] This comparative example is a zinc metal anode obtained by simply wiping the surface of a pure zinc foil with ultrapure water and anhydrous ethanol.

[0118] Two pieces of the zinc metal anode of this comparative example are placed together with 2 mol / L zinc sulfate (electrolyte) and Whatman glass fiber (separator) into a 2032 button cell to obtain the symmetric cell of Comparative Example 10; one piece of the zinc metal anode of this comparative example and one piece of sodium vanadate positive electrode are placed together with 2 mol / L zinc sulfate (electrolyte) and Whatman glass fiber (separator) into a 2032 button cell to obtain the zinc cell of Comparative Example 10.

[0119] Figure 1 is a scanning electron microscope image of the zinc metal anode 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 anode. Its morphology presents an ordered and regular texture structure, and this micro-morphology feature can further enhance the inherent hydrophobic properties of the long chain.

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

[0121] Figure 3 is a Tafel curve plot of the zinc metal anodes prepared in Comparative Example 10 and Example 1 under a three-electrode system at a scanning speed of 1 mVs -1The linear sweep voltammetry curve below. From Figure 3 It can be seen 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⁻¹), the hydrogen evolution overpotential is significantly lower. -2 The electrode exhibits a more positive corresponding potential (-1.209V vs. -1.112V). This phenomenon fully confirms that the hydrophobic-zinc-philic interface protective layer can effectively reduce the water molecule content and reactivity at the electrode interface, thereby significantly inhibiting the occurrence of hydrogen evolution side reactions.

[0122] Figure 4 The symmetrical cells prepared in Comparative Example 10 and Example 1 were tested at a current density of 2 mA / cm². -2 The deposition surface capacity is 1 mAh cm⁻¹ -2 The cycle performance graph. (Example) Figure 4 As shown, in Comparative Example 10, the zinc metal anode exhibited frequent fluctuations in polarization voltage after less than 80 hours of stable cycling. This indicates severe zinc dendrite growth, byproduct accumulation, and intense hydrogen evolution side reactions during the deposition / stripping process, making it difficult to achieve highly stable cycling. In contrast, in Example 1, the zinc metal anode with a hydrophobic-zincophilic interface protective layer demonstrated excellent cycling stability, operating stably for 2000 hours. This fully demonstrates that the hydrophobic-zincophilic interface protective layer can significantly improve the reversibility of zinc deposition / stripping and suppress the occurrence of side reactions.

[0123] Figure 5 and Figure 6 The figures show the rate cycling curves of the symmetric cells prepared in Comparative Example 10 and Example 1, respectively. Figure 5 What we can see is that during cycling with the zinc metal anode in ratio 10, the polarization of the battery increases rapidly with increasing current density, reaching a peak at 10 mA cm⁻¹. 2 The subsequent violent fluctuations and rapid failure indicate poor interfacial stability. In contrast, the zinc metal anode with a hydrophobic-zinc-philic interfacial protective layer in Example 1 exhibits excellent rate performance, even at 40 mA / cm². -2 It can still operate stably under high current density ( Figure 6 It is worth noting that when the current drops back to 1 mA cm -2 Even under extreme current conditions, the battery can still recover stable deposition / stripping behavior, confirming the high structural stability of the protective layer. Furthermore, the zinc-philic sites in the hydrophobic-zinc-philic interface protective layer promote uniform zinc ion deposition, while the hydrophobic layer effectively suppresses water-related side reactions, thus maintaining stable zinc deposition / stripping behavior at high current densities.

[0124] Figure 7 and Figure 8respectively, were prepared in Comparative Example 10 and Example 1 were measured at a current density of 5 A g -1 The long cycle performance plots of the zinc batteries are shown in FIG. 2. It can be clearly found 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 reversible cycles with a capacity retention of up to 92%. However, the zinc battery in Comparative Example 10 not only provides a lower capacity (about 155 mAh g -1 during cycling, but also degrades rapidly during cycling, with a capacity retention of less than 40% after only 1000 cycles. 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 zinc deposition / stripping reversibility.

[0125] The contact angle tests of the zinc metal anodes prepared in Examples 1-4 and Comparative Examples 1-10 were performed, 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] It can be seen from Table 1 that 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 interface protection layer after introducing the hydrophobic chain can effectively isolate the reaction between water molecules and the zinc metal anode at the interface. Among them, the contact angle of Example 1 is the largest, indicating that the hydrophobic effect improved by this example is the most obvious.

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

[0130] Table 2

[0131]

[0132]

[0133] It can be seen from Table 2 that 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 interface protection layer after introducing the zincophilic group 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 zincophilic effect improved by this example is the most obvious.

[0134] The above is a specific description of the preferred embodiment of the application, but the application is not limited to the described embodiments, and those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A method for preparing a hydrophobic-zincophilic interfacial protective layer for high-rate zinc metal negative electrodes, characterized in that, The method comprises the following steps: (1) dissolving polyvinyl alcohol derivatives in a polar solvent to obtain a precursor solution; (2) dropping the precursor solution onto the surface of zinc metal, placing it on a spin coater after there are no bubbles left on the surface, and uniformly spin coating the precursor on the surface of zinc metal by using a gradient spin coating process; (3) placing the spin-coated zinc metal in a saturated salt solution to undergo a phase separation process, thereby obtaining a zinc metal negative electrode with a hydrophobic-zincophilic interfacial protective layer. In step (1), the polyvinyl alcohol derivatives include at least one of short-chain aminated polyvinyl alcohol, long-chain aminated polyvinyl alcohol, short-chain quaternized polyvinyl alcohol, long-chain quaternized polyvinyl alcohol, short-chain amide polyvinyl alcohol, and long-chain amide polyvinyl alcohol. In step (1), the polar solvent includes at least one of water, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide. 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, and N,N-dimethylacetamide.

2. The method according to claim 1, wherein the method is characterized by, In step (1), the mass fraction of the precursor solution is 2-20%.

3. The method according to claim 1, wherein the method is characterized by: In step (2), the gradient spin coating process includes a low-speed pre-coating process and a high-speed spin coating process.

4. The method according to claim 3, wherein the method is characterized by, In step (2), the low-speed pre-coating process has a rotation speed of 100-500 r / min, and the low-speed pre-coating time is 5-30 seconds.

5. The method according to claim 3, wherein the method is characterized by: In step (2), the high-speed spin coating process has a rotation speed of 1000-5000 r / min, and the high-speed spin coating time is 10-60 seconds.

6. The method according to claim 1, wherein the method is characterized by: The phase separation process takes 6-72 hours.

7. A hydrophobic-zincophilic interfacial protective layer of a high-rate zinc metal negative electrode prepared by the method of any one of claims 1-6.

8. Use of the hydrophobic-zincophilic interphase protective layer of the high- rate zinc metal negative electrode according to claim 7 in the electrochemical field, characterized by, The application includes preparing a symmetric battery or a zinc battery, wherein the symmetric battery is prepared by coupling two zinc metal negative electrodes with hydrophobic-zincophilic interfacial protective layers to obtain a symmetric battery, and the zinc battery is prepared by coupling a zinc metal negative electrode with a hydrophobic-zincophilic interfacial protective layer with a positive electrode to obtain a zinc battery.

Images