A method for preparing and applying a self-healing polymer interface layer modified zinc metal anode.

Abstract

This invention discloses a method for preparing and applying a self-healing polymer interface layer modified zinc metal anode. Polyvinyl alcohol, sodium hydroxide, and acrylonitrile are dissolved in a solvent to synthesize an intermediate product. Further, an acetone solution of the intermediate product is dynamically crosslinked with boric acid to obtain a fast-conducting self-healing polymer solution. This solution is then loaded onto the surface of a zinc metal anode using a spin-coating method to obtain the zinc anode. This invention also provides its application in energy storage batteries such as aqueous zinc-ion batteries. The room-temperature ionic conductivity of this polymer interface layer reaches 0.63 mS / cm. ‑1 The zinc ion transport number reached 0.64, and the activation energy decreased to 58.53 kJ / mol. ‑1 The assembled battery has a specific capacity of 101.4 mAh g. ‑1 With a coulomb efficiency of 99.7% and a capacity retention rate of 74.0% after 1000 cycles, it combines high stability with excellent cycle performance.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion batteries, specifically to a method for preparing and applying a self-healing polymer interface layer modified zinc metal anode. Background Technology

[0002] In recent years, with the deepening global energy structure transformation towards cleaner and lower-carbon energy, building efficient, stable, and low-cost large-scale energy storage technologies has become a key link in promoting the large-scale utilization of renewable energy and the safe and stable operation of the power grid. Among various electrochemical energy storage systems, aqueous zinc-ion batteries are widely considered a promising energy storage technology due to their significant advantages such as abundant resources, environmental friendliness, high safety, and large theoretical capacity. However, the commercial application of aqueous zinc-ion batteries still faces a series of technical challenges, especially at the zinc metal anode interface. Problems such as uncontrolled growth of zinc dendrites, interfacial side reactions, and hydrogen evolution reactions not only reduce the coulombic efficiency and cycle life of the battery but also bring serious safety hazards.

[0003] To address the aforementioned issues, constructing a functional interface layer on the zinc anode surface has become an effective strategy for improving battery performance. Among these, polymer-based interface layers show significant application potential due to their advantages such as wide availability of raw materials, mature synthesis processes, strong processability, and low cost. For example, patent CN117317398A discloses an aqueous zinc-ion battery and electrolyte. By crosslinking amino-containing and hydroxyl-containing polymers under certain conditions, these polymers are introduced into the electrolyte as composite additives. Since hydrogen bonds can form between amino and hydroxyl groups, the composite polymers constitute a spatial network structure, promoting the directional and uniform deposition of zinc ions, thereby effectively inhibiting the growth of zinc dendrites and improving the electrochemical stability and cycle life of zinc ions.

[0004] While existing technologies offer numerous methods to improve zinc-ion battery performance by constructing polymer interface layers, these methods all have limitations. For example, they generally exhibit low ionic conductivity and are prone to mechanical damage or chemical degradation during long-term cycling. The resulting defects are difficult to repair spontaneously, ultimately leading to interface layer failure and battery performance degradation. Therefore, developing polymer interface layers that combine high ionic conductivity with self-healing capabilities is crucial for suppressing zinc dendrite growth, stabilizing the electrode / electrolyte interface, and improving battery cycle stability and safety. It is also a key technological approach to driving the practical application of aqueous zinc-ion batteries. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for preparing and applying a self-healing polymer interface layer modified zinc metal anode. This method combines adjusting the degree of acrylonitrile substitution for PVA with optimizing the dynamic crosslinking point density of boric acid to prepare the self-healing polymer interface layer modified zinc metal anode, thereby solving the problems of poor performance and cycle stability in existing zinc-ion batteries.

[0006] To achieve the above objectives, the present invention first provides a method for preparing a self-healing polymer interface layer modified zinc metal anode, the method comprising the following steps: (1) Preparation of intermediate products: Polyvinyl alcohol (PVA), sodium hydroxide and acrylonitrile are dissolved in solvents respectively, mixed to obtain a precursor solution, stirred at constant temperature, and deionized water is added to precipitate the product. The white product suspended in the upper layer is collected, washed, and dried under vacuum to obtain the intermediate product. (2) Preparation of zinc metal anode with self-healing polymer interface layer: Dissolve the intermediate product obtained in step (1) in a solvent, add dynamic crosslinking agent solution to make dynamic crosslinking reaction, and after the reaction, immediately coat the obtained solution on the surface of zinc metal anode, and after vacuum drying, the self-healing polymer interface layer modified zinc metal anode SMP@Zn is obtained.

[0007] In one embodiment of the present invention, in step (1), the PVA can be various commercially available polyvinyl alcohols with different molecular weights and degrees of hydrolysis, such as BP-05 (degree of polymerization 550~650, degree of hydrolysis 86%~89%), PVA1799 (degree of polymerization 1700~1800, degree of hydrolysis 98%~99%), PVA 2488 (degree of polymerization 2400~2500, degree of hydrolysis 86%~89%), etc., preferably PVA 1799.

[0008] In one embodiment of the present invention, in step (1), when dissolving polyvinyl alcohol, the solvent may be deionized water or dimethyl sulfoxide (DMSO), preferably deionized water, and the dissolution temperature is 90℃~98℃, preferably 95℃, and the concentration of the PVA solution after dissolution is 0.05 g / mL. -1 ~0.20 g mL -1 Preferably 0.11 g mL -1 .

[0009] In one embodiment of the present invention, in step (1), when dissolving sodium hydroxide, the solvent may be deionized water or ethanol, preferably deionized water. The concentration of the sodium hydroxide solution after dissolution is 0.04 g / mL. -1 ~0.18 g mL -1 Preferably 0.10 g mL -1 .

[0010] In one embodiment of the present invention, in step (1), when dissolving acrylonitrile, the solvent can be any one of acetone, diethyl ether, ethanol, etc., preferably acetone. After dissolution, the concentration of the acrylonitrile solution is 0.37 g / mL. -1 ~2.0 g mL -1 Preferably 0.75 g mL -1 .

[0011] In one embodiment of the present invention, in step (1), the mass ratio of PVA to sodium hydroxide in the mixed precursor solution is 0.5 to 2:1, preferably 1.1:1.

[0012] In one embodiment of the present invention, in step (1), the mass ratio of PVA to acrylonitrile in the mixed precursor solution is 1:2~5, preferably 1:3.4.

[0013] In one embodiment of the present invention, in step (1), the temperature during constant temperature stirring is 0~30°C, preferably 25°C, and the stirring time is 6~48 h, preferably 24 h.

[0014] In one embodiment of the present invention, in step (1), during the process of adding deionized water to precipitate the product, the amount of deionized water added is 70% to 125% of the volume of the precursor solution, preferably 100%.

[0015] In one embodiment of the present invention, in step (1), the temperature during vacuum drying is 45°C to 150°C, preferably 60°C, and the drying time is 10 h to 30 h, preferably 12 h.

[0016] In one embodiment of the present invention, in step (2), the solvent in the intermediate product solution is acetone, and the concentration of the intermediate product after dissolution is 0.02 g / mL. -1 ~0.10 g mL -1 Preferably 0.05 g mL -1 .

[0017] In one embodiment of the present invention, in step (2), the dynamic crosslinking agent is one of boric acid, sodium tetraborate, or phenylboronic acid and its derivatives. The derivatives of phenylboronic acid include one of 4-phenylphenylboronic acid, 3-aminophenylboronic acid, and 4-methoxyphenylboronic acid. Boric acid is preferred as the dynamic crosslinking agent. The solvent for the dynamic crosslinking agent solution is one of deionized water, ethanol, or glycerol, preferably deionized water. The concentration of the dynamic crosslinking agent solution is 0.01 g / mL. -1 ~0.05 g mL -1Preferably 0.015 g mL -1 .

[0018] In one embodiment of the present invention, in step (2), the time for the dynamic cross-linking reaction to occur is 6 to 48 hours, preferably 24 hours.

[0019] In one embodiment of the present invention, in step (2), the coating is spin coating or scraping coating, the spin coating speed is 200 rpm to 1000 rpm, preferably 800 rpm, and the spin coating time is 20 s to 80 s, preferably 40 s.

[0020] In one embodiment of the present invention, in step (2), the tool used for coating is an SZQ-4 four-blade wet film preparation tool, and the coating thickness on the four sides can be 10, 15, 20, or 25 μm, preferably 10 μm.

[0021] In one embodiment of the present invention, in step (2), the vacuum drying temperature is 40°C to 100°C, preferably 80°C, and the vacuum drying time is 10 h to 40 h, preferably 24 h.

[0022] The present invention also provides a self-healing polymer interface layer modified zinc metal anode SMP@Zn prepared according to the above method.

[0023] The present invention also provides an application of the above-mentioned self-healing polymer interface layer modified zinc metal anode in energy storage batteries.

[0024] In one embodiment of the present invention, the energy storage battery is selected from zinc batteries, and more preferably, the zinc battery is selected from aqueous zinc-ion batteries.

[0025] In one embodiment of the present invention, the load pressure of the assembled battery is 80~120 Psi, preferably 90 Psi.

[0026] In one embodiment of the present invention, the energy storage battery includes a positive electrode, a zinc metal negative electrode modified with the aforementioned self-healing polymer interface layer, and an electrolyte. In this invention, there are no specific limitations on the positive electrode and electrolyte of the energy storage battery; positive electrode materials and electrolytes known in the art can be used. Exemplarily, the positive electrode includes at least one of α-MnO2, β-MnO2, and V2O5. Exemplarily, the electrolyte solvent contains at least one of ZnSO4·7H2O, ZnCl2·6H2O, Zn(CF3SO3)2, and Zn(CH3COO)2.

[0027] Beneficial effects: (1) In this invention, acrylonitrile-substituted polyvinyl alcohol is prepared by reacting acrylonitrile, sodium hydroxide and polyvinyl alcohol. Then, a dynamic crosslinking agent is used to crosslink the intermediate product to obtain a self-healing polymer interface layer modified zinc metal anode SMP@Zn. By combining acrylonitrile side group modification and boric acid dynamic crosslinking process, the steric hindrance of the polymer side group is improved, the mobility of polymer chain segments is enhanced, thereby reducing the glass transition temperature of the polymer and significantly improving the ionic conductivity of the polymer interface layer. In addition, the strong chain segment mobility also endows the polymer interface layer with good self-healing ability, thus enabling it to quickly repair defects at room temperature.

[0028] (2) By adjusting the amount of acrylonitrile, the degree of substitution of acrylonitrile is controlled. On the one hand, the degree of substitution of acrylonitrile ensures that the polymer main chain has sufficient chain segment movement freedom, which is the kinetic basis for achieving rapid self-repair and ion transport; on the other hand, it avoids the chain segment rigidity caused by excessively high polar cyano groups and prevents the ionic conductivity from decreasing.

[0029] (3) The present invention controls the density of dynamic crosslinking points by controlling the amount of dynamic crosslinking agent added, so that the polymer structure will not hinder the movement of polymer chains due to excessive crosslinking, thereby ensuring extremely high ionic conductivity; at the same time, it can efficiently dissipate stress through reversible bonding-dissociation process, and provide strong driving entropy force for chain segment movement after fracture, thereby achieving efficient self-repair.

[0030] (4) The ionic conductivity of the polymer interface layer of the present invention can reach 0.63 mS / cm. -1 The zinc ion transference number can reach 0.64; it features high ionic conductivity, good self-healing properties, strong adaptability, and low production cost, meeting the practical application requirements of aqueous zinc-ion batteries. Furthermore, the exchange current density of the polymer interface layer reaches 16.71 mA cm⁻¹. -2 The activation energy decreased to 58.53 kJ / mol. -1 This significantly improves the reactivity of the electrode / electrolyte interface and the rate performance of the battery.

[0031] (5) The polymer interface layer of the present invention can be uniformly formed on the zinc metal surface by spin coating without the need for additional base film support, thus forming a stable protective structure. This process simplifies the electrode preparation process and eliminates the interfacial compatibility problem between the traditional interface layer and the substrate, significantly improving the cycle life and high-current charge-discharge performance of zinc metal batteries.

[0032] (6) The polymer interface layer of the present invention has good self-adaptability and can spontaneously and dynamically adapt to changes in the electrode surface to form long-term protection, thereby improving the cycle stability of the battery. In addition, the main materials of the polymer interface layer (mainly PVA and acrylonitrile) are inexpensive and have low cost. Moreover, the preparation process of the polymer interface layer of the present invention is simple, with significant cost advantages, which lowers the threshold for industrial production.

[0033] (7) The aqueous zinc-ion battery prepared with the polymer interface layer of the present invention can operate stably and has a high specific capacity of up to 101.4 mAh g. -1 The coulombic efficiency is as high as 99.7%, and the capacity retention rate is 74.0% after 1000 charge-discharge cycles, indicating that the prepared zinc-ion battery has good cycle stability. Attached Figure Description

[0034] Figure 1 The images shown are scanning electron microscope images of SMP@Zn in Example 1 and the corresponding surface energy dispersive spectroscopy test results. Figure 2 This is a scanning electron microscope image of the SMP@Zn cross section in Example 1; Figure 3 The exchange current density of SMP@Zn in Example 1 was tested; Figure 4 The activation energy of SMP@Zn in Example 1 was tested; Figure 5 Zinc ion transference number test of SMP@Zn in Example 1; Figure 6 Electrochemical impedance spectroscopy (EIS) of SMP@Zn in Example 1; Figure 7 The electrochemical impedance spectroscopy (EIS) of SMP@SS in Example 1 is shown below. Figure 8 This is a self-healing digital photograph of the SMP in Example 2; Figure 9 Glass transition temperature test of SMP in Example 2; Figure 10 This is a charge-discharge curve of the aqueous zinc-ion battery in Example 3; Figure 11 The graph shows the cycle performance of the aqueous zinc-ion battery in Example 3. Figure 12 The electrochemical impedance spectroscopy diagram is shown for the polymer-modified stainless steel negative electrode obtained in Comparative Example 2. Figure 13 The activation energy of the polymer interface layer obtained in Comparative Example 2 was tested. Figure 14 For the zinc ion transference number test of the polymer interface layer obtained in Comparative Example 3; Figure 15 This is a cross-sectional scanning electron microscope image of the polymer interface layer obtained in Comparative Example 4; Figure 16 Electrochemical impedance spectroscopy (EIS) of the polymer interface layer obtained in Comparative Example 4 was performed. Figure 17 This is a cross-sectional scanning electron microscope image of the polymer interface layer obtained in Comparative Example 5; Figure 18 Electrochemical impedance spectroscopy (EIS) of the polymer interface layer obtained in Comparative Example 5; Figure 19 The cycling performance diagram of the aqueous zinc-ion battery in Comparative Example 6 is shown. Figure 20 The exchange current density of the polymer interface layer obtained in Comparative Example 7 was measured. Figure 21 Electrochemical impedance spectroscopy (EIS) was performed on the polymer interface layer obtained in Comparative Example 8. Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0036] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0037] Electrochemical performance testing of polymer interface layer 1. Ionic conductivity of the self-healing polymer interface layer: The prepared polymer interface layer was spin-coated onto two stainless steel sheets (SS), and then assembled into a 2032 battery case. Electrochemical impedance spectroscopy was performed using an electrochemical workstation. The ionic conductivity of the interface layer was calculated using the following formula: σ = L / (S*R) Where L is the polymer interface layer, S is the area of ​​the stainless steel sheet facing each other, and R is the measured electrode body impedance.

[0038] 2. Activation energy of self-healing polymer interface layer: The polymer interface layer was spin-coated onto two zinc anodes, and a Zn / / Zn symmetric cell was assembled in a 2032-type battery case. Electrochemical impedance spectroscopy (EIS) was performed at 30℃, 40℃, 50℃, 60℃, 70℃, and 80℃ using an electrochemical workstation, with a test frequency of 10 ppm. -2 ~10 6 Hz.

[0039] 3. Zn in a self-healing polymer interface layer 2+ Number of migrations (t) Zn 2+ ): A polymer interface layer was spin-coated onto two zinc anodes, and a Zn / / Zn symmetrical cell was assembled in a 2032-type battery case. After 24 hours of aging, the zinc ion transport number was measured using AC impedance spectroscopy and potentiostatic chronoamperometry, with a polarization voltage of 25 mV and a polarization time of 3000 s. The zinc ion transport number can be calculated using the following formula:

[0040] Where I0 and I S The current values ​​before and after polarization are R0 and R, respectively. S The values ​​are the interface impedances obtained before and after polarization, respectively, and ΔV is the applied polarization voltage.

[0041] Example 1 A method for preparing a self-healing polymer interface layer modified zinc metal anode SMP@Zn includes the following steps: (1) Preparation of intermediate products: 2.2 g of polyvinyl alcohol (PVA 1799) was dissolved in 20 mL of deionized water, 2.0 g of sodium hydroxide was dissolved in 20 mL of deionized water, and 15 g of acrylonitrile was dissolved in 20 mL of acetone. The mixture was used to obtain a precursor solution. The precursor solution was stirred at 25 °C for 24 h. After the reaction was completed, 60 mL of deionized water was added to precipitate the product. The white product suspended in the upper layer was collected, washed three times with deionized water, and dried under vacuum at 60 °C for 12 h. The resulting yellow product was the intermediate product.

[0042] (2) Preparation of self-healing polymer interface layer modified metal anode: 4.0 g of intermediate product was dissolved in 80 mL of acetone, and 10 mL of aqueous solution containing 0.15 g of boric acid was added. The mixture was stirred until homogeneous to induce a dynamic cross-linking reaction. After 24 h of reaction, the resulting solution was spin-coated onto the cleaned zinc metal anode and stainless steel anode surfaces, respectively. The spin-coating speed was controlled at 800 rpm and the spin-coating time was 40 s. After vacuum drying at 80 °C for 24 h, the self-healing polymer interface layer modified zinc metal anode SMP@Zn and stainless steel anode SMP@SS were obtained.

[0043] The surface microstructure of the self-healing polymer interface layer modified zinc metal anode SMP@Zn obtained in Example 1 was observed by scanning electron microscopy (SEM). The results are as follows: Figure 1 As shown, Figure 1The results show that the polymer interface layer synthesized by the above method exhibits a smooth surface. Energy dispersive spectroscopy (EDS) analysis of the elemental distribution in the polymer interface layer reveals that the various elements are uniformly distributed in all dimensions within the electrode prepared using the above synthesis method.

[0044] The cross-sectional microstructure of the self-healing polymer interface layer modified zinc metal anode SMP@Zn was observed by scanning electron microscopy (SEM), and the results are as follows: Figure 2 As shown, Figure 2 The results show that the polymer interface layer synthesized by the above preparation method has a thickness of only 500 nm and good contact with the zinc anode surface.

[0045] The test results for the exchange current density, activation energy, zinc ion transport number, and electrochemical impedance of SMP@Zn in Example 1 are as follows: Figures 3-7 As shown, the exchange current density of SMP@Zn is 16.71 mA cm⁻¹. -2 The activation energy is 58.53 kJ / mol. -1 The zinc ion transport number is 0.64, the kinetic impedance is 123.0 Ω, the impedance of SMP@SS is 2.5 Ω, and its conductivity, calculated using the above formula, is 0.63 mS / cm. -1 .

[0046] Example 2 The difference between Example 2 and Example 1 is that the dynamically cross-linked solution obtained in step two was transferred to a Teflon container and placed in a 70°C ventilated oven to evaporate the solvent, thus obtaining a self-healing polymer. The glass transition temperature of the obtained polymer was determined by differential scanning calorimetry, and the results are as follows: Figure 8 As shown in the figure. The obtained polymer was cut open and subjected to a self-healing test; the results are as follows. Figure 9 As shown.

[0047] Tests showed that the polymer obtained in Example 2 had a glass transition temperature of 49.8°C and exhibited good self-healing ability at room temperature.

[0048] Example 3 An aqueous zinc-ion battery is prepared as follows: (1) Preparation of cathode material: 0.380 g of MnSO4·H2O was dissolved in 15 mL of deionized water to obtain solution A, and then 0.237 g of KMnO4 was dissolved in 15 mL of deionized water to obtain solution B. Finally, solution B was slowly added to solution A to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor liner and heated at 160 °C for 12 h. After cooling to room temperature, the resulting particles were centrifuged, washed three times with deionized water, and dried in a vacuum oven at 80 °C for 12 h to obtain α-MnO2.

[0049] (2) Preparation of positive electrode sheet: α-MnO2 positive electrode active material powder, conductive carbon black and binder PVDF were uniformly mixed in a mass ratio of 7:2:1. N-methylpyrrolidone solution (the amount added was 3:1 of the solid powder mass ratio) was added. The mixture was stirred and ultrasonically prepared in a room-temperature drying environment to form a uniform slurry. The slurry was then coated onto a stainless steel mesh current collector, transferred to a vacuum drying oven for drying, and finally cut into 12 mm diameter discs to prepare α-MnO2 positive electrode sheets.

[0050] (3) Using the α-MnO2 positive electrode sheet prepared in step (2) as the positive electrode, 2 M ZnSO4 + 0.1 M MnSO4 as the electrolyte, and a glass fiber D with a diameter of 18 mm as the separator, the self-healing polymer interface layer modified zinc metal negative electrode SMP@Zn prepared in Example 1 was used as the negative electrode. The cells were assembled into a 2032 button cell in an atmospheric environment, denoted as Battery 1. Battery 1 was subjected to charge-discharge tests at room temperature, with a test voltage range of 0.8 V to 1.8 V. The test results are as follows: Figure 8 and 9 As shown.

[0051] Figure 10 and 11 This demonstrates battery 1 at a current density of 1 A g. -1 The figure shows the discharge ratio of the first cycle after activation, the charge-discharge curve of the first cycle, and the specific capacity and coulombic efficiency records from the first cycle to the 1150th cycle. It can be seen from the figure that the specific capacity of battery 1 in the first cycle after activation is 137.0 mAh g⁻¹. -1 The coulombic efficiency is 97.1%, and the capacity retention rate after 1150 cycles is 74.0%, indicating that the battery has good reversibility and cycle stability.

[0052] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the amount of sodium hydroxide used is 5.0g.

[0053] A method for preparing an intermediate product: 2.2 g PVA 1799 was dissolved in 20 mL of deionized water, 5.0 g sodium hydroxide was dissolved in 20 mL of deionized water, and 15 g acrylonitrile was dissolved in 20 mL of acetone. The mixture was then used to obtain a precursor solution. The precursor solution was stirred at 25 °C for 24 h. After the reaction was completed, 60 mL of deionized water was added, and no product was precipitated.

[0054] The experimental results of Comparative Example 1 show that the ratio of PVA to sodium hydroxide has a significant impact on the synthesis of intermediate products, and improper control of the ratio may prevent the formation of intermediate products.

[0055] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that polyvinyl alcohol was used directly as the polymer.

[0056] A method for preparing a polymer interface layer includes the following steps: 2.2 g of PVA 1799 was dissolved in 20 mL of deionized water at 95 °C, and then spin-coated at 800 rpm for 40 s to load it onto the surfaces of zinc metal anode and stainless steel anode. The polymer interface layer was obtained by vacuum drying at 80 °C for 24 h.

[0057] The results showed that, Figure 12 and 13 As shown, the stainless steel negative electrode prepared by this method has an impedance of 6.6 Ω, and its conductivity, calculated by the formula, is only 0.24 mS / cm. -1 Furthermore, its zinc-loaded anode activation energy is as high as 83.01 kJ / mol. -1 .

[0058] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the cross-linking step with boric acid in step (2) is omitted, and 4g of intermediate product is directly dissolved in 80 mL of acetone and then spin-coated.

[0059] like Figure 14 As shown, the results revealed that the polymer interface layer prepared by this method had a low zinc ion migration number of only 0.34, and the interface layer did not have self-healing ability.

[0060] Comparative Example 4 The difference between Comparative Example 4 and Comparative Example 1 is that the spin coating speed is 200 rpm.

[0061] like Figure 15As shown, the results revealed that the polymer interface layer prepared by this method has a thickness of approximately 2 μm. A thicker polymer interface layer requires ions to traverse a longer distance, resulting in more collisions and interactions with atoms, molecules, or lattice elements, consuming more energy and slowing down the process. Macroscopically, this manifests as a decrease in ionic conductivity and a significant increase in diffusion resistance. Figure 16 It can be seen that the kinetic impedance of the zinc metal anode in Comparative Example 4 is 430.1 Ω, which does not meet the requirements for fast ion conduction at the zinc metal anode interface layer.

[0062] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the solution after dynamic cross-linking was coated onto the surface of the zinc metal anode by a scraping method, and the thickness of the scraping was 25 μm using a four-blade wet film preparation device.

[0063] The results showed that, Figure 17 As shown, the polymer interface layer prepared by this method has a thickness of approximately 5 μm. Figure 18 The dynamic impedance shown is 974.9 Ω, which does not meet the requirements for fast ion conduction in the zinc metal anode interface layer.

[0064] Comparative Example 6 An aqueous zinc-ion battery is prepared as follows: (1) Preparation of cathode material: 0.380 g of MnSO4·H2O was dissolved in 15 mL of deionized water to obtain solution A, and then 0.237 g of KMnO4 was dissolved in 15 mL of deionized water to obtain solution B. Finally, solution B was slowly added to solution A to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor liner and heated at 160 °C for 12 h. After cooling to room temperature, the resulting particles were centrifuged, washed three times with deionized water, and dried in a vacuum oven at 80 °C for 12 h to obtain α-MnO2.

[0065] (2) Preparation of positive electrode sheet: α-MnO2 positive electrode active material powder, conductive carbon black and binder PVDF were uniformly mixed in a mass ratio of 7:2:1. N-methylpyrrolidone solution (the amount added was 3:1 of the solid powder mass ratio) was added. The mixture was stirred and ultrasonically prepared in a room-temperature drying environment to form a uniform slurry. The slurry was then coated onto a stainless steel mesh current collector, transferred to a vacuum drying oven for drying, and finally cut into 12 mm diameter discs to prepare α-MnO2 positive electrode sheets.

[0066] (3) Using the α-MnO2 positive electrode sheet prepared in step (2) as the positive electrode, 2 M ZnSO4 + 0.1 M MnSO4 as the electrolyte, and a glass fiber D with a diameter of 18 mm as the separator, the self-healing polymer interface layer modified zinc metal negative electrode prepared in Comparative Example 3 was used as the negative electrode. The cells were assembled into a 2032 button cell in an atmospheric environment, denoted as battery 2. Battery 2 was subjected to charge-discharge tests at room temperature, with a test voltage range of 0.8 V to 1.8 V. The test results are as follows: Figure 19 As shown, battery 2 has poor cycle stability and lower battery capacity.

[0067] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the amount of acrylonitrile used in step (1) was increased to 22 g.

[0068] The results showed that the polymer interface layer prepared by this method lacked self-healing ability due to excessive acrylonitrile substitution and insufficient hydroxyl density. Figure 20 As shown, the excessively high density of cyano groups leads to excessive coordination of zinc ions in the electrode, resulting in decreased electrode reaction kinetics and a reduction in exchange current density to 13.31 mA cm⁻¹ compared to Example 1. -2 This means that its rate performance deteriorates, and the battery's operating temperature is severely limited.

[0069] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that the amount of boric acid used in step (2) was increased to 0.30 g.

[0070] The results showed that the polymer interface layer prepared by this method had an excessively high boric acid content and a high density of crosslinking points, which significantly reduced the size of the crosslinking network and hindered the migration of zinc ions. Therefore, Figure 21 It can be seen that its dynamic impedance is 169.2Ω, which is inferior to 123.0Ω in Example 1.

[0071] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a self-healing polymer interface layer modified zinc metal anode, characterized in that, Includes the following steps: (1) Preparation of intermediate products: Polyvinyl alcohol, sodium hydroxide and acrylonitrile are dissolved in solvents respectively, mixed to obtain precursor solution, stirred at constant temperature and deionized water is added to precipitate the product, the white product suspended in the upper layer is collected, washed and dried under vacuum to obtain intermediate product. In the precursor solution, the mass ratio of polyvinyl alcohol to sodium hydroxide is 0.5~2:1, and the mass ratio of polyvinyl alcohol to acrylonitrile is 1:2~5. (2) Preparation of zinc metal anode with self-healing polymer interface layer: The intermediate product obtained in step (1) is dissolved in a solvent, and a dynamic crosslinking agent solution is added to induce a dynamic crosslinking reaction. After the reaction, the resulting solution is immediately coated on the surface of the zinc metal anode, and after vacuum drying, the self-healing polymer interface layer modified zinc metal anode SMP@Zn is obtained; wherein, the solvent is acetone, and the concentration of the intermediate product after dissolution is 0.02~0.10 g / mL. -1 The dynamic crosslinking agent is one of boric acid, sodium tetraborate, or phenylboronic acid and its derivatives. The derivatives of phenylboronic acid include one of 4-phenylphenylboronic acid, 3-aminophenylboronic acid, and 4-methoxyphenylboronic acid. The concentration of the dynamic crosslinking agent solution is 0.01~0.05 g / mL. -1 The coating is performed by spin coating or blade coating. The spin coating speed is 800 rpm to 1000 rpm, the spin coating time is 20 s to 80 s, and the thickness of the wet film after blade coating is 10 μm.

2. The preparation method according to claim 1, characterized in that, In step (1), the solvent for dissolving polyvinyl alcohol is deionized water or dimethyl sulfoxide, the dissolution temperature is 90℃~98℃, and the concentration of the PVA solution after dissolution is 0.05~0.20 g / mL. -1 The solvent used to dissolve sodium hydroxide is deionized water or ethanol, and the concentration of the sodium hydroxide solution after dissolution is 0.04~0.18 g / mL. -1 The solvent for dissolving acrylonitrile can be any one of acetone, diethyl ether, or ethanol, and the concentration of the acrylonitrile solution after dissolution should be 0.37~2.0 g / mL. -1 .

3. The preparation method according to claim 1, characterized in that, In step (1), the temperature during constant temperature stirring is 0~30°C, the stirring time is 6~48 h, the amount of deionized water added is 70~125% of the volume of the precursor solution, the temperature during vacuum drying is 45°C~150°C, and the drying time is 10 h~30 h.

4. The preparation method according to claim 1, characterized in that, In step (2), the solvent of the dynamic crosslinking agent solution is one of deionized water, ethanol or glycerol, and the time for the dynamic crosslinking reaction is 6 to 48 hours.

5. The preparation method according to claim 1, characterized in that, In step (2), the coating is spin coating or blade coating, the vacuum drying temperature is 40°C~100°C, and the vacuum drying time is 10 h~40 h.

6. A self-healing polymer interface layer modified zinc metal anode SMP@Zn prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the self-healing polymer interface layer modified zinc metal anode as described in claim 6 in energy storage batteries.

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