An ultrathin gel polymer interfacial modified zinc negative electrode material and a preparation method thereof

Abstract

The present application relates to a kind of ultra-thin gel polymer interface modified zinc negative electrode material and its preparation method, belong to zinc ion battery negative electrode material technical field.The negative electrode material is by zinc-containing metal and its surface by PVDF-HFP, PEG and inorganic conductive small molecule by hydrogen bond crosslinking form ultra-thin gel polymer interface layer, wherein, ultra-thin gel polymer interface layer not only can reduce zinc-containing metal and water-based electrolyte contact interface area, also can play the role of uniform ion deposition and electron distribution, avoid the corrosion of zinc-containing metal and dendrite effect when long cycle, so it can improve the electrochemical performance of zinc ion battery;In addition, using spin coating method forms ultra-thin gel polymer interface layer on the surface of zinc-containing metal, simple operation, and it is easy to form the gel polymer interface layer of uniform thickness and relatively thin.

Description

Technical Field

[0001] This invention relates to an ultrathin gel polymer interface modified zinc anode material and its preparation method, belonging to the technical field of zinc-ion battery anode materials. Background Technology

[0002] The increasing demand for renewable energy has driven the development of safe, low-cost, and environmentally friendly electrochemical energy storage systems. Although lithium-ion batteries currently hold a dominant position in the energy storage market, the depletion of lithium resources and their rising prices necessitate the search for next-generation energy storage systems. Zinc metal, with its advantages in reserves, resource distribution, and theoretical specific capacity (5855 mAh cm⁻¹), is a promising candidate for this market. -3 Given its advantages, the rechargeable zinc-ion battery is considered an ideal alternative to lithium-ion batteries in the future.

[0003] In recent years, various rechargeable zinc-ion batteries, such as Zn-MnO2, Zn-V2O5, and Zn-LiMn2O4 systems, have become research hotspots, using metallic zinc as the negative electrode, organic / aqueous electrolytes, and ion-intercalation / deintercalation positive electrodes. Currently, the development of rechargeable zinc-ion batteries faces severe challenges, including high self-discharge, low stability, and limited cycle life, stemming from the electrode / electrolyte interface behavior (such as zinc dendrites caused by uneven metal deposition and thermodynamically driven gas-generating corrosion). To address these challenges, researchers have proposed methods including interface modification, three-dimensional electrode structure design, and high-concentration electrolytes to construct stable zinc metal / electrolyte interfaces.

[0004] Interface modification can not only effectively alleviate interfacial corrosion reactions but also suppress dendrite growth by regulating the zinc ion flow at the interface. Polymer gel interface modification, such as PVDF and PVA, has been proven to effectively regulate the metal ion flow and interfacial electric field at alkali metal interfaces, achieving a dendrite-free deposition / exfoliation process for metal anodes. However, current research on gel polymer protective layers still mainly focuses on single-component gel polymers. These polymers have regular structures, are prone to crystallization, and have poor chain segment mobility, thus reducing the ionic conductivity of the interface layer. In addition, such interface layers typically have poor mechanical strength and thermal stability. Regulating the composition, characteristic functional groups, and microstructure of polymers is one of the effective means to enhance the mechanical strength, chemical / electrochemical stability, and processability of gel polymer interface-modified metal anodes in the future.

[0005] Currently, blade coating and polymer solution immersion remain the most direct and effective methods for constructing gel polymer protective layers on zinc anodes. However, none of these methods can produce ultrathin coatings (<10µm), and the latter even struggles to guarantee the uniformity of the interface layer. More importantly, thicker coatings reduce energy density while increasing interfacial resistance. Summary of the Invention

[0006] To address the problems existing in current polymer-modified zinc anodes, this invention provides an ultrathin gel polymer interface-modified zinc anode material and its preparation method. An ultrathin gel polymer interface layer is formed on a zinc-containing metal surface by hydrogen bonding crosslinking of polyvinylidene fluoride-hexafluoropropylene, polyethylene glycol, and inorganic conductive small molecules. This material features a three-dimensional porous structure, abundant nucleation sites, and high ionic conductivity, which reduces the contact area between the zinc-containing metal and the aqueous electrolyte, resulting in uniform ion deposition and electron distribution. This avoids corrosion and dendrite effects of the zinc-containing metal during long-term cycling, thus improving the electrochemical performance of zinc-ion batteries. Furthermore, the spin-coating method for forming the ultrathin gel polymer interface layer on the zinc-containing metal surface is simple to operate and easily produces a uniform and thin gel polymer interface layer.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] A zinc anode material with an ultrathin gel polymer interface modification, wherein the anode material is composed of a zinc-containing metal and an ultrathin gel polymer interface layer formed by hydrogen bonding of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene glycol (PEG) and inorganic conductive small molecules.

[0009] The mass ratio of PVDF-HFP, PEG, and inorganic conductive small molecules is 1:(0.1~0.6):(0.01~0.2). The inorganic conductive small molecules are selected from Ti3C2, Ti2C, Nb2C, V2C, and Mo2C type MXene materials or graphene oxide materials.

[0010] Preferably, the molecular weight of PEG is 200 to 6000.

[0011] Preferably, the zinc-containing metal is zinc foil or zinc alloy foil.

[0012] Preferably, the thickness of the ultrathin gel polymer interface layer is 150–600 nm.

[0013] The preparation method of the ultrathin gel polymer interface-modified zinc anode material of the present invention specifically includes the following steps:

[0014] (1) PVDF-HFP is dissolved in an organic solvent and mixed evenly to obtain a PVHP solution;

[0015] (2) Add PEG to PVHP solution and stir at 40-70℃ for 0.5-2h to obtain PHP solution;

[0016] (3) Add the inorganic conductive small molecule material powder to an organic solvent, disperse it evenly by ultrasonication, and then add it to a PHP solution. Stir at 50-70℃ for 0.5-2 hours to obtain a spin-coating solution.

[0017] (4) Place the zinc-containing metal material on a spin coater, uniformly drop the spin coating solution onto the surface of the zinc-containing metal material, set the rotation speed and coating time, and then spin coat it onto the zinc-containing metal material to form a polymer interface layer.

[0018] (5) The zinc-containing metal material containing the polymer interface layer is annealed at 40-60°C for 30-90 minutes to obtain the negative electrode material.

[0019] In step (1), the organic solvent should not react with PVDF-HFP, but should be able to dissolve PVDF-HFP and be volatile. Preferably, acetone, N,N-dimethylformyl, N-methylpyrrolidone or isopropanone is used.

[0020] Preferably, the concentration of the PVHP solution in step (1) is 50–150 mg / mL.

[0021] In step (3), the organic solvent should not react with the inorganic conductive small molecules, and it only needs to be able to disperse the inorganic conductive small molecules and be volatile. Anhydrous ethanol or anhydrous methanol is preferred.

[0022] Preferably, in step (3), the dispersion concentration of the inorganic conductive small molecule material in the organic solvent is 15–60 mg / mL.

[0023] Preferably, the concentration of the PVHP solution in step (1) is 50-150 mg / mL, the dispersion concentration of the inorganic conductive small molecule material in the organic solvent in step (3) is 15-60 mg / mL, and the rotation speed of the spin coater in step (4) is 500-6000 r / min and the coating time is 30-600 s.

[0024] Beneficial effects:

[0025] (1) In the PVDF-HFP interface layer, the present invention introduces PEG and inorganic conductive small molecules to generate weak hydrogen bond interactions, which effectively improves the ionic conductivity of the interface layer. At the same time, the introduction of inorganic conductive small molecules can induce the formation of ion transport pathways inside the polymer and provide abundant nucleation sites, which can play a role in dispersing tip electrons, uniform ion beam deposition and uniform electron distribution. Therefore, the ultrathin gel polymer interface layer can effectively inhibit the growth of zinc dendrites.

[0026] (2) The present invention utilizes a nanoscale interface modification layer constructed by a pre-reacted polymer to physically separate the metal electrode from the electrolyte, effectively mitigating the occurrence of side reactions such as corrosion and passivation; at the same time, compared with the larger electrolyte-electrode interface resistance of the micron-scale interface layer, the ultrathin gel polymer interface layer can complete faster kinetic energy transfer at a lower interface impedance, thus enabling the acquisition of a high-energy-density metal anode with extended cycle life.

[0027] (3) The method of preparing the interface modification layer by spin coating is simple and easy to implement, effectively avoiding the dependence on binder in the blade coating method. Moreover, the controllable film formation process can not only strengthen the bonding force between zinc metal and gel polymer film and reduce the thickness of interface layer, but also promote the weak hydrogen bond interaction between PVDF-HFP, PEG and inorganic conductive small molecules, forming more amorphous phase and porous structure, thereby improving the ionic conductivity of interface layer.

[0028] (4) The annealing treatment used in this invention can effectively control the micropore structure of the gel polymer interface layer. Therefore, by adjusting the annealing temperature and time, an interface protective film with suitable pore size and porosity can be formed, thereby effectively controlling the zinc ion flow during the deposition process and suppressing zinc dendrites.

[0029] (5) The process of preparing ultrathin gel polymer interface layer by spin coating is simple, has good thickness uniformity, and can achieve preparation of thickness at the nanometer level. It has good application prospects in the interface modification of zinc-ion battery anode materials. Attached Figure Description

[0030] Figure 1 The image shows a surface scanning electron microscope (SEM) image of the PVPM@Zn anode material prepared in Example 1.

[0031] Figure 2 The surface scanning electron microscope image of the PVHP@Zn anode material prepared for Comparative Example 1.

[0032] Figure 3 The image shows a cross-sectional scanning electron microscope image of the PVPM@Zn anode material prepared in Example 1.

[0033] Figure 4 The battery assembled using the PVPM@Zn anode material prepared in Example 1 as the positive and negative electrodes operates at a current density of 1 mA / cm². 2 The capacity is 1mAh / cm 2 Cyclic performance graph.

[0034] Figure 5 It is a battery assembled using pure zinc foil as the positive and negative electrodes at a current density of 1 mA / cm². 2 The capacity is 1mAh / cm2 Cyclic performance graph.

[0035] Figure 6 The battery assembled using the PVPM@Zn anode material prepared in Example 1 as the positive and negative electrodes operates at a current density of 1 mA / cm². 2 The capacity is 0.5mAh / cm³. 2 The surface scanning electron microscope image after 20 cycles.

[0036] Figure 7 It is a battery assembled using pure zinc foil as the positive and negative electrodes at a current density of 1 mA / cm². 2 The capacity is 0.5mAh / cm³. 2 The surface scanning electron microscope image after 20 cycles.

[0037] Figure 8 This is a comparison chart of the long-cycle performance of full cells assembled using the PVPM@Zn anode material prepared in Example 1 and pure zinc foil as anodes, respectively, at a rate of 1A / g.

[0038] Figure 9 The battery assembled using the PVHP@Zn anode material prepared in Comparative Example 1 as the positive and negative electrodes operates at a current density of 1 mA / cm². 2 The capacity is 1mAh / cm 2 Cyclic performance graph.

[0039] Figure 10 The graph shows the long-term cycling performance of a full cell assembled using the PVHP@Zn anode material prepared in Comparative Example 1 as the anode at a rate of 1 A / g.

[0040] Figure 11 The surface scanning electron microscope image of the PVHM@Zn anode material prepared for Comparative Example 2 is shown.

[0041] Figure 12 A battery assembled using the PVHM@Zn anode material prepared in Comparative Example 2 as both positive and negative electrodes operates at a current density of 1 mA / cm². 2 The capacity is 1mAh / cm 2 Cyclic performance graph.

[0042] Figure 13 The image shows a cross-sectional scanning electron microscope image of the PVPM@Zn anode material prepared for Comparative Example 3.

[0043] Figure 14 The battery assembled using PVPM@Zn prepared in Comparative Example 3 as the positive and negative electrodes operates at a current density of 1 mA / cm². 2 The capacity is 1mAh / cm 2 Cyclic performance graph.

[0044] Figure 15 The image shows a cross-sectional scanning electron microscope image of the PVPM@Zn anode material prepared for Comparative Example 4.

[0045] Figure 16 The graph shows the long-term cycling performance of a full cell assembled using the PVPM@Zn anode material prepared in Comparative Example 4 as the anode at a rate of 1 A / g. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the methods described are conventional methods, and the raw materials described are obtainable from publicly available commercial sources.

[0047] In the following embodiments:

[0048] SEM characterization: The microstructure of the samples was observed using a field emission scanning electron microscope (Hitachi SU-7) with an accelerating voltage of 3.0 kV;

[0049] Assembly of CR 2032 batteries: Using the negative electrode material prepared in the examples as both positive and negative electrodes, glass fiber as the separator, 3M zinc trifluoromethanesulfonate (Zn(OTf)2) as the solute and deionized water as the solvent in the electrolyte, a pair of batteries were assembled. Alternatively, using the negative electrode material prepared in the examples as the negative electrode, V2O5 as the positive electrode, 3M zinc trifluoromethanesulfonate (Zn(OTf)2) as the solute and deionized water as the solvent in the electrolyte, a full battery was assembled. The electrochemical performance of the CR 2032 batteries was tested using the Land system, and the test data was recorded using software.

[0050] Example 1

[0051] (1) Dissolve 1g of PVDF-HFP in 10g of acetone, heat to 60℃ and stir for 1h to fully dissolve and obtain PVHP solution;

[0052] (2) Add 0.5g PEG-4000 to the PVHP solution prepared in step (1) and stir at 60℃ for 1h to obtain PHP solution;

[0053] (3) Dissolve 0.2g of Ti3C2 type MXene powder in 10mL of anhydrous ethanol and disperse it by ultrasonication for 2h to obtain MXene ethanol solution; take 1mL of MXene ethanol solution and add it to the PHP solution in step (2), stir at 60℃ for 1h to obtain PVPM spin coating solution;

[0054] (4) Polish the zinc foil with 5000 grit sandpaper, and clean the zinc foil surface twice each with deionized water and anhydrous ethanol. Cut the zinc foil into appropriate sizes and place it on a spin coater. Add the PVPM spin coating solution evenly to the zinc foil surface. Set the rotation speed to 2000 r / min and the coating time to 90 s. Then spin coat the zinc foil to form a polymer interface layer with a thickness of 300 nm.

[0055] (5) The zinc foil containing the polymer interface layer is placed in an oven at 60°C and annealed for 30 minutes to obtain an ultrathin gel polymer interface modified zinc anode material, abbreviated as PVPM@Zn anode material.

[0056] The surface morphology of the prepared PVPM@Zn anode material was characterized, from Figure 1 As can be seen from the surface SEM images, the PVPM interface layer uniformly covers the zinc foil surface, and is similar to the PVHP interface layer prepared on the zinc foil surface in Comparative Example 1. Figure 2 In contrast, the PVHP interface layer has no porous structure, while the PVPM interface layer prepared by introducing PEG and MXene exhibits a clear three-dimensional porous structure. Figure 3 The cross-sectional SEM images further demonstrate that the PVPM interface layer was successfully and uniformly coated on the zinc foil surface with a thickness of 300 nm.

[0057] The PVPM@Zn anode material prepared in this embodiment was used to assemble a PVPM@Zn||PVPM@Zn battery. AC impedance testing was performed using a CHI660D electrochemical workstation at 10°C intervals within a temperature range of 20–60°C. -2 ~10 5 With an AC amplitude of 5mV and a frequency of Hz, the interfacial activation energy of PVPM@Zn is obtained as 16.8kJ / mol based on the Allonius equation fitting.

[0058] The PVPM@Zn anode material prepared in this embodiment and pure zinc foil without interface layer modification were used as positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance was tested. Figure 4 The test results show that at a current density of 1 mA / cm² 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of PVPM@Zn remained flat after 1200 hours of cycling, with a small overpotential and no significant fluctuations, demonstrating excellent cycling performance. Figure 5 The test results show that at a current density of 1 mA / cm² 2 and a capacity of 1mAh / cm 2Under these conditions, the potential of pure zinc foil fluctuates significantly after 100 hours of cycling, the overpotential increases rapidly during the cycling process, and an internal short circuit occurs after about 190 hours of cycling.

[0059] The PVPM@Zn anode material prepared in this embodiment and pure zinc foil without interface layer modification were used as positive and negative electrodes to assemble a CR 2032 type battery. The battery was tested at a current density of 1 mA / cm². 2 And a capacity of 0.5mAh / cm 2 The PVPM@Zn anode was cycled for 20 cycles, and then the microstructure of the anode after 20 cycles was observed. The surface morphology of the PVPM@Zn anode after cycling was clear and smooth, with no obvious dendrite growth, as shown in the image. Figure 6 As shown; the surface of the pure zinc foil negative electrode is rough after cycling, and a large number of thin-film zinc dendrites are peeled off from the metallic zinc matrix, becoming "dead zinc," as shown. Figure 7 As shown.

[0060] The PVPM@Zn anode material prepared in this embodiment and pure zinc foil without interface layer modification were used as anodes, and V2O5 was used as cathode to assemble CR 2032 full cells. Long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). Figure 8 The test results show that the full cell with PVPM@Zn as the negative electrode exhibits excellent cycle stability, with a capacity retention of 93.6% after about 500 cycles, which is much higher than the capacity retention of the full cell with pure zinc foil as the negative electrode after about 500 cycles (only 40.7%).

[0061] Example 2

[0062] Based on Example 1, the Ti3C2 type MXene powder in step (3) of Example 1 is replaced with V2C type MXene, while other conditions and steps remain unchanged. Then, step (3) yields the PVPV spin-coating solution, and step (5) yields the PVPV@Zn anode material.

[0063] The morphology of the prepared PVPV@Zn anode material was characterized. According to the test results, the PVPV interface layer with a thickness of 300 nm is uniformly covered on the zinc foil surface, and the PVPV interface layer exhibits obvious three-dimensional pore structure.

[0064] The PVPV@Zn anode material prepared in this embodiment was used to assemble a PVPV@Zn||PVPV@Zn battery. AC impedance testing was performed using a CHI660D electrochemical workstation at 10°C intervals within a temperature range of 20–60°C. -2 ~10 5With an AC amplitude of 5mV and a frequency of Hz, the interfacial activation energy of PVPV@Zn is obtained as 13.4kJ / mol based on the Allonius equation fitting.

[0065] The PVPV@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. The cycle performance was tested at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the PVPV@Zn anode remained flat after 1800 hours, with a small overpotential and no significant fluctuations, demonstrating excellent cycle performance.

[0066] The PVPV@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery. The battery was tested at a current density of 1 mA / cm². 2 And a capacity of 0.5mAh / cm 2 The PVPV@Zn anode was cycled for 20 cycles, and then the microstructure of the PVPV@Zn anode after 20 cycles was observed. The test results showed that the surface morphology of the PVPV@Zn anode after cycling was clear and smooth, with no obvious dendrite growth.

[0067] Using the PVPV@Zn anode material prepared in this embodiment as the anode and V2O5 as the cathode, a CR2032 type full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). The test results show that the full cell with PVPV@Zn as the anode exhibits excellent cycling stability, retaining 94.5% of its capacity after approximately 500 cycles.

[0068] Example 3

[0069] Based on Example 1, the Ti3C2 type MXene powder in step (3) of Example 1 is replaced with Mo2C type MXene, while other conditions and steps remain unchanged. Then, step (3) yields a PVPMo spin-coated solution, and step (5) yields a PVPMo@Zn anode material.

[0070] The morphology of the prepared PVPMo@Zn anode material was characterized. According to the test results, the 300 nm thick PVPMo interface layer uniformly covers the zinc foil surface, and the PVPMo interface layer exhibits obvious three-dimensional pore structure.

[0071] The PVPMo@Zn anode material prepared in this embodiment was used to assemble a PVPMo@Zn||PVPMo@Zn battery. AC impedance testing was performed using a CHI660D electrochemical workstation at 10°C intervals within a temperature range of 20–60°C. -2 ~10 5With an AC amplitude of 5mV and a frequency of Hz, the interfacial activation energy of PVPMo@Zn is obtained as 15.6kJ / mol based on the Allonius equation fitting.

[0072] The PVPMo@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. The cycle performance was tested at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the PVPMo@Zn anode remained flat after 1500 hours, with a small overpotential and no significant fluctuations, demonstrating excellent cycle performance.

[0073] The PVPMo@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery. The battery was tested at a current density of 1 mA / cm². 2 With a capacity of 0.5mAh / cm³ 2 The PVPMo@Zn anode was cycled for 20 cycles, and then the microstructure of the PVPMo@Zn anode after 20 cycles was observed. The test results showed that the surface morphology of the PVPMo@Zn anode after cycling was clear and smooth, with no obvious dendrite growth.

[0074] Using the PVPMo@Zn anode material prepared in this embodiment as the anode and V2O5 as the cathode, a CR 2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). The test results show that the full cell with PVPMo@Zn as the anode exhibits excellent cycling stability, retaining 95.8% of its capacity after approximately 500 cycles.

[0075] Example 4

[0076] Based on Example 1, the Ti3C2 type MXene powder in step (3) of Example 1 is replaced with graphene oxide (GO), and other conditions and steps remain unchanged. Then, step (3) yields a PVPG spin-coating solution, and step (5) yields a PVPG@Zn anode material.

[0077] The morphology of the prepared PVPG@Zn anode material was characterized. According to the test results, the PVPG interface layer with a thickness of 300 nm was uniformly covered on the zinc foil surface, and the PVPG interface layer showed obvious three-dimensional channel structure.

[0078] The PVPG@Zn anode material prepared in this embodiment was used to assemble a PVPG@Zn||PVPG@Zn battery. AC impedance testing was performed using a CHI660D electrochemical workstation at 10°C intervals within a temperature range of 20–60°C. -2 ~10 5With an AC amplitude of 5mV and a frequency of Hz, the interfacial activation energy of PVPG@Zn is 17.6kJ / mol according to the Allonius equation.

[0079] The PVPG@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. The cycle performance was tested at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the PVPG@Zn anode remained flat after 1300 hours, with a small overpotential and no significant fluctuations, demonstrating excellent cycle performance.

[0080] The PVPG@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery. The battery was tested at a current density of 1 mA / cm². 2 With a capacity of 0.5mAh / cm³ 2 The PVPG@Zn anode was cycled for 20 cycles, and then the microstructure of the PVPG@Zn anode after 20 cycles was observed. The test results showed that the surface morphology of the PVPG@Zn anode after cycling was clear and smooth, with no obvious dendrite growth.

[0081] Using the PVPG@Zn anode material prepared in this embodiment as the anode and V2O5 as the cathode, a CR2032 type full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). The test results show that the full cell with PVPG@Zn as the anode exhibits excellent cycling stability, retaining 92.5% of its capacity after approximately 500 cycles.

[0082] Example 5

[0083] Based on Example 1, the rotation speed of the spin coater in step (4) was set to 4000 r / min and the coating time was set to 120 s, while other steps and conditions remained unchanged, and PVPM@Zn anode material was obtained accordingly.

[0084] The surface morphology of the prepared PVPM@Zn anode material was characterized. The test results showed that a PVPM interface layer with a thickness of 240 nm was uniformly covered on the zinc foil surface, and the PVPM interface layer exhibited obvious three-dimensional channel structure.

[0085] The PVPM@Zn anode material prepared in this embodiment was used to assemble a PVPM@Zn||PVPM@Zn battery. AC impedance testing was performed using a CHI660D electrochemical workstation at 10°C intervals within a temperature range of 20–60°C. -2 ~10 5With an AC amplitude of 5mV and a frequency of Hz, the interfacial activation energy of PVPM@Zn is 14.7kJ / mol according to the Allonius equation.

[0086] The PVPM@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. The cycle performance was tested at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the PVPM@Zn anode remained flat after 1100 hours, with a small overpotential and no significant fluctuations, demonstrating excellent cycle performance.

[0087] The PVPM@Zn anode material prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 type battery. The battery was tested at a current density of 1 mA / cm². 2 With a capacity of 0.5mAh / cm³ 2 The PVPM@Zn anode was cycled for 20 cycles, and then the microstructure of the PVPM@Zn anode after 20 cycles was observed. The test results showed that the surface morphology of the PVPM@Zn anode after cycling was clear and smooth, with no obvious dendrite growth.

[0088] Using the PVPM@Zn anode material prepared in this embodiment as the anode and V2O5 as the cathode, a CR 2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). The test results show that the full cell with PVPM@Zn as the anode exhibits excellent cycling stability, retaining 96.7% of its capacity after approximately 500 cycles.

[0089] Comparative Example 1

[0090] (1) Dissolve 1g of PVDF-HFP in 10g of acetone, heat to 60℃ and stir for 1h to fully dissolve and obtain PVHP solution;

[0091] (2) Polish the zinc foil with 5000 grit sandpaper, and clean the zinc foil surface twice each with deionized water and anhydrous ethanol. Cut the zinc foil into appropriate sizes and place it on a spin coater. Add PVHP solution evenly to the zinc foil surface. Set the rotation speed to 2000 r / min and the coating time to 90 s. Then spin coat the zinc foil to form a polymer interface layer with a thickness of 280 nm.

[0092] (3) The zinc foil containing the polymer interface layer is placed in an oven at 60°C and annealed for 30 minutes to obtain the zinc anode material modified by the gel polymer interface, which is abbreviated as PVHP@Zn anode material.

[0093] The morphology of the prepared PVHP@Zn anode material was characterized, from Figure 2The SEM images show that the PVHP interface layer is uniformly covered on the zinc foil surface, but there is no pore structure. In addition, the characterization results of the cross-sectional SEM show that the thickness of the PVHP interface layer is 280 nm.

[0094] The prepared PVHP@Zn anode material was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. Figure 9 As shown, at a current density of 1 mA / cm² 2 and a capacity of 1mAh / cm 2 Under these conditions, the PVHP@Zn anode exhibits stable cycling with low polarization for the first 100 hours. However, after 100 hours, the cycling stability begins to decrease, the polarization increases, and the electrode fails after 200 hours of cycling.

[0095] Using the prepared PVHP@Zn anode material as the anode and V2O5 as the cathode, a CR 2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). Figure 10 As shown, the full cell with PVHP@Zn as the negative electrode retains 61.9% of its capacity after approximately 500 cycles.

[0096] Comparative Example 2

[0097] (1) Dissolve 1g of PVDF-HFP in 10g of acetone, heat to 60℃ and stir for 1h to fully dissolve and obtain PVHP solution;

[0098] (2) Dissolve 0.2g of Ti3C2 type MXene powder in 10mL of anhydrous ethanol and disperse it by ultrasonication for 2h to obtain MXene ethanol solution; take 1mL of MXene ethanol solution and add it to the PVHP solution in step (2), stir at 60℃ for 1h to obtain PVHM spin-coating solution;

[0099] (3) Polish the zinc foil with 5000 grit sandpaper, and clean the zinc foil surface twice each with deionized water and anhydrous ethanol. Cut the zinc foil into appropriate sizes and place it on a spin coater. Add the PVHM spin coating solution evenly to the zinc foil surface. Set the rotation speed to 2000 r / min and the coating time to 90 s. Then spin coat the zinc foil to form a polymer interface layer with a thickness of 290 nm.

[0100] (4) The zinc foil containing the polymer interface layer is placed in an oven at 60°C and annealed for 30 minutes to obtain the zinc anode material modified by the gel polymer interface, which is abbreviated as PVHM@Zn anode material.

[0101] The surface morphology of the prepared PVHM@Zn anode material was characterized, from Figure 11The surface SEM images show that the PVHM interface layer uniformly covers the zinc foil surface, exhibiting a porous structure. However, the size and distribution of the pores are highly uneven, and the PVHM surface is relatively rough. Furthermore, the cross-sectional SEM characterization results indicate that the thickness of the PVHM interface layer is 290 nm.

[0102] The prepared PVHM@Zn anode material was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. Figure 12 As shown, at a current density of 1 mA / cm² 2 and a capacity of 1mAh / cm 2 Under these conditions, the PVHM@Zn anode exhibits stable cycling with low polarization for the first 240 hours. However, after 240 hours, the cycling stability begins to decrease, the polarization increases, and the electrode fails after 260 hours of cycling.

[0103] Using the prepared PVHM@Zn anode material as the anode and V2O5 as the cathode, a CR 2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). The test results show that, compared to pure zinc and PVHP@Zn anodes, the full cell with PVHM@Zn as the anode exhibits better cycle stability, retaining 82.3% of its capacity after approximately 500 cycles.

[0104] Comparative Example 3

[0105] Based on Example 1, the rotation speed of the spin coater in step (4) was set to 300 r / min and the coating time was set to 180 s, while other steps and conditions remained unchanged, and PVPM@Zn anode material was obtained accordingly.

[0106] The surface morphology of the prepared PVPM@Zn anode material was characterized, such as... Figure 13 As shown, a PVPM interface layer with a thickness of 8 μm is uniformly covered on the zinc foil surface, and the PVPM interface layer exhibits a distinct three-dimensional pore structure.

[0107] A PVPM@Zn||PVPM@Zn battery was assembled using the prepared PVPM@Zn anode material. AC impedance was measured using a CHI660D electrochemical workstation at 10°C intervals within a temperature range of 20–60°C. -2 ~10 5 With an AC amplitude of 5mV and a frequency of Hz, the interfacial activation energy of PVPM@Zn is found to be 24.4kJ / mol based on the Allonius equation fitting.

[0108] The prepared PVPM@Zn anode material was used as the positive and negative electrodes to assemble a CR 2032 type battery, and its cycle performance was tested. Figure 14 As shown, at a current density of 1 mA / cm² 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the PVPM@Zn anode remains flat after 400 hours of cycling. However, due to the excessively thick interface film, the transport barrier is high, the overpotential is large, and the polarization is obvious.

[0109] Using the prepared PVPM@Zn anode material as the anode and V2O5 as the cathode, a CR 2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). The test results show that the full cell with PVPM@Zn as the anode exhibits good cycle stability; however, due to its high polarization, the battery capacity decays rapidly, with a capacity retention of approximately 67.8% after 500 cycles.

[0110] Comparative Example 4

[0111] (1) Dissolve 2g of PVDF-HFP in 21g of acetone, heat to 60℃ and stir for 1h to fully dissolve, and obtain PVHP solution;

[0112] (2) Add 1g of PEG-4000 to the PVHP solution prepared in step (1) and stir at 60℃ for 1h to obtain the PHP solution;

[0113] (3) Dissolve 0.2g of Ti3C2 type MXene powder in 10mL of anhydrous ethanol, stir for 12h, and ultrasonically disperse for 2h to obtain MXene ethanol solution; take 2mL of MXene ethanol solution and add it to the PHP solution in step (2), stir at 60℃ for 1h to obtain PVPM solution;

[0114] (4) Polish the zinc foil with 5000 grit sandpaper, and clean the zinc foil surface twice each with deionized water and anhydrous ethanol. Cut the zinc foil into appropriate sizes and place it in a polytetrafluoroethylene mold. Pour 10 mL of PVPM solution evenly onto the zinc foil surface. After standing in the air for 30 min to form a film, transfer it to a vacuum oven and dry it at 60 °C for 12 h to obtain a gel polymer interface layer with a thickness of about 5 μm.

[0115] The surface morphology of the prepared PVPM@Zn anode material was characterized, from Figure 15 The SEM images show that the PVPM interface layer is not in close contact with the zinc metal, and there is even partial detachment. The surface of the PVPM interface layer is rough and does not show a porous structure. The thickness of the PVPM interface layer is about 5 μm.

[0116] The prepared PVPM@Zn anode material was used as the positive and negative electrodes to assemble a CR 2032 type battery, and cycle performance tests were conducted. The cycle performance was tested at a current density of 1 mA / cm².2 and a capacity of 1mAh / cm 2 Under these conditions, the PVPM@Zn negative electrode exhibits poor cycling stability and significant polarization, resulting in a short circuit after 320 hours of cycling.

[0117] Using the prepared PVPM@Zn anode material as the anode and V2O5 as the cathode, a CR 2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 1 A / g (approximately 5C). Figure 16 As shown, this full cell not only has a low initial capacity, but also poor cycle stability, with a capacity retention of only 48.67% after about 500 cycles.

[0118] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A zinc anode material modified with an ultrathin gel polymer interface, characterized in that: It consists of a zinc-containing metal and an ultrathin gel polymer interface layer formed by hydrogen bonding of PVDF-HFP, PEG and inorganic conductive small molecules on its surface; The mass ratio of PVDF-HFP, PEG and inorganic conductive small molecules is 1:(0.1~0.6):(0.01~0.2), and the inorganic conductive small molecules are selected from Ti3C2, Ti2C, Nb2C, V2C and Mo2C type MXene materials or graphene oxide materials. The thickness of the ultrathin gel polymer interface layer is 150–600 nm.

2. The zinc anode material with an ultrathin gel polymer interface modification according to claim 1, characterized in that: PEG has a molecular weight of 200–6000; the zinc-containing metal is zinc foil or zinc alloy foil.

3. A method for preparing an ultrathin gel polymer interface-modified zinc anode material as described in claim 1 or 2, characterized in that: Specifically, the following steps are included: (1) PVDF-HFP is dissolved in an organic solvent and mixed evenly to obtain a PVHP solution; (2) Add PEG to PVHP solution and stir at 40-70℃ for 0.5-2h to obtain PHP solution; (3) Add the inorganic conductive small molecule material powder to an organic solvent, disperse it evenly by ultrasonication, and then add it to a PHP solution. Stir at 50-70℃ for 0.5-2 hours to obtain a spin-coating solution. (4) Place the zinc-containing metal material on a spin coater, uniformly drop the spin coating solution onto the surface of the zinc-containing metal material, set the rotation speed and coating time, and then spin coat it onto the zinc-containing metal material to form a polymer interface layer. (5) The zinc-containing metal material containing the polymer interface layer is annealed at 40-60°C for 30-90 minutes to obtain the negative electrode material.

4. The method for preparing an ultrathin gel polymer interface-modified zinc anode material according to claim 3, characterized in that: In step (1), the organic solvent is acetone, N,N-dimethylformyl, N-methylpyrrolidone or isopropanone.

5. The method for preparing an ultrathin gel polymer interface-modified zinc anode material according to claim 3, characterized in that: The concentration of the PVHP solution in step (1) is 50-150 mg / mL.

6. The method for preparing an ultrathin gel polymer interface-modified zinc anode material according to claim 3, characterized in that: In step (3), the organic solvent is anhydrous ethanol or anhydrous methanol.

7. The method for preparing an ultrathin gel polymer interface-modified zinc anode material according to claim 3, characterized in that: In step (3), the dispersion concentration of the inorganic conductive small molecule material in the organic solvent is 15-60 mg / mL.

8. The method for preparing an ultrathin gel polymer interface-modified zinc anode material according to claim 3, characterized in that: In step (1), the concentration of the PVHP solution is 50–150 mg / mL, and in step (3), the dispersion concentration of the inorganic conductive small molecule material in the organic solvent is 15–60 mg / mL.

9. The method for preparing an ultrathin gel polymer interface-modified zinc anode material according to claim 8, characterized in that: In step (4), the rotation speed of the rotary coater is 500-6000 r / min and the coating time is 30-600 s.

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