A zinc powder film material, a preparation method and application thereof

Abstract

The application discloses a zinc powder film material, a preparation method and application thereof, and the zinc powder film material is a flexible material and has through holes; the hole diameter of the zinc powder film material is 30-300 um, and the porosity is 10%-30%. In the application, the porous flexible zinc powder film material is prepared by taking zinc alloy powder (250-500 mesh) as a main material, taking polyvinylidene fluoride as a binder and a film forming agent, taking ammonium bicarbonate as a pore forming agent, and taking indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide and sodium carboxymethyl cellulose as additives, and the porous flexible zinc powder film material is prepared by adopting a scraping coating method. Excellent electrochemical performance shows that the zinc powder film material has a very large application prospect as a zinc ion battery and a zinc-nickel secondary battery negative active material. Meanwhile, the electrode material preparation process is simple and controllable, the equipment is simple, and the method is easy to carry out large-scale production.

Description

Technical Field

[0001] This application relates to a zinc powder film material, its preparation method, and its application, belonging to the fields of membrane electrode preparation and electrochemical technology. Background Technology

[0002] Aqueous zinc-ion batteries are secondary batteries that use metallic zinc as the negative electrode and manganese oxide, vanadium oxide, or Prussian blue analogues as the positive electrode. These batteries feature high energy density, good safety, environmental friendliness, and low cost. Based on these advantages, aqueous zinc-ion batteries hold promise for future applications in large-scale energy storage, power supplies for small electric vehicles, and power sources for electric toys. Therefore, research on aqueous zinc-ion batteries and their electrode materials is attracting increasing attention.

[0003] Zinc-nickel secondary batteries are a type of secondary battery that uses metallic zinc as the negative electrode and nickel hydroxide / nickel hydroxyl oxide as the positive electrode. They are characterized by high energy density, good safety, and low cost. Based on these advantages, zinc-nickel secondary batteries are expected to be used in the future as power sources and starting power supplies for small electric vehicles, and they also have the potential to replace lead-acid batteries that currently use toxic lead compounds. Therefore, research on zinc-nickel secondary batteries and their electrode materials is attracting increasing attention.

[0004] Currently, zinc anodes suffer from short cycle life in both neutral electrolytes used in aqueous zinc-ion batteries and alkaline electrolytes used in zinc-nickel secondary batteries. This is mainly due to issues such as dendrite growth, hydrogen evolution reaction, passivation, and electrode deformation, leading to rapid capacity decay. Therefore, exploring zinc anodes with high specific capacity and long cycle life is a key research focus for both zinc-ion and zinc-nickel secondary batteries. Current modification methods for zinc anodes in zinc-ion batteries primarily involve coating the zinc surface with various materials, such as inorganic materials like calcium carbonate and carbon dioxide, and organic polymer coatings like polyimide coatings. These coatings can limit the uneven two-dimensional diffusion of zinc ions on the zinc anode surface, thereby inhibiting zinc dendrite growth and extending the electrode's lifespan. However, coating technology is only suitable for low areal capacities (1-2 mAh cm⁻¹). -2 The effect is significant at lower areal capacities, but limited at higher areal capacities. Another commonly used modification method is to prepare three-dimensional framework materials to support zinc, such as three-dimensional foamed copper supporting zinc or tin-plated three-dimensional foamed copper supporting zinc. The prepared three-dimensional composite anode has a larger specific surface area, which can reduce the areal current density of the electrode, thereby delaying the dendrite growth of the zinc anode; at the same time, the porous structure in the framework can accommodate a small amount of zinc dendrites generated on the electrode, which can also extend the service life of the zinc electrode. However, this method not only suffers from the problem of galvanic corrosion between zinc metal and framework materials, but also has a complex preparation process and the price of framework materials is usually several times or even tens of times that of zinc metal, resulting in excessively high costs.

[0005] Currently, research on the modification of zinc-nickel secondary battery anodes mainly includes the modification of zinc oxide, the active material in the discharge state, and the addition of additives to the zinc anode. Methods commonly used for zinc oxide modification include composite methods and the preparation of materials with different morphologies and particle sizes. For example, zinc oxide composites with polypyrrole enhance the material's conductivity and inhibit zinc oxide dissolution, thereby improving the material's discharge specific capacity and cycle stability. However, this method introduces composites without charge-discharge properties, thus reducing the material's specific capacity. Nano-zinc oxide preparation is also a common method. By controlling the particle size of the synthesized zinc oxide material to the nanoscale, allowing for epitaxial growth rather than dendrite growth, its cycle life is enhanced. Simultaneously, small-particle-size zinc oxide has a larger specific surface area, which is beneficial for increasing its contact area with the electrolyte, thereby reducing electrode polarization and increasing discharge specific capacity. However, because the specific morphology changes with charge-discharge cycles, it can only extend the cycle life to a limited extent. Research on zinc anode additives mainly involves adding conductive agents, hydrogen evolution inhibitors, and structural shaping agents to zinc powder, followed by coating onto tin-plated copper mesh. The cost of current collectors such as tin-plated copper mesh is typically several times, or even tens of times, higher than that of active materials like zinc powder, leading to increased costs for zinc anodes. Furthermore, the weight of the current collector also reduces the discharge specific energy of the zinc anode. Summary of the Invention

[0006] The purpose of this application is to overcome the shortcomings of the prior art by providing a method for preparing a porous flexible zinc powder film anode. This invention uses zinc alloy powder (250-500 mesh) as the main material, polyvinylidene fluoride (PVDF) as a binder and film-forming agent, ammonium bicarbonate as a pore-forming agent, and indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide, and sodium carboxymethyl cellulose as additives, and is prepared by a coating method. The use of PVDF as a binder and film-forming agent in this invention gives the prepared film electrode a flexible characteristic. Compared with zinc foil electrodes and 3D framework zinc anode materials, it can be bent at any angle without affecting charge-discharge performance. In this invention, by using ammonium bicarbonate as a pore-forming agent, pores with a diameter of approximately 30-300 μm can be uniformly prepared on the film electrode, increasing the specific surface area of ​​the electrode, thereby effectively reducing the surface current density of the electrode, thus inhibiting dendrite growth during charging and extending the electrode's service life. Furthermore, the prepared pores can accommodate a small amount of zinc dendrites formed during charging, further extending the electrode's service life. In this invention, indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide and sodium carboxymethyl cellulose are used as additives to effectively suppress the hydrogen evolution reaction and passivation of the electrode, thereby improving the charge and discharge efficiency and service life of the electrode, and finally obtaining a membrane anode with high utilization and long cycle life.

[0007] According to one aspect of this application, a zinc powder film material is provided, the zinc powder film material being a flexible material having through-holes; the pore diameter of the zinc powder film material is 30-300 μm, and the porosity is 10%-30%.

[0008] Optionally, the thickness of the zinc powder film material is 50µm to 200µm.

[0009] Optionally, the zinc powder film material includes zinc alloy powder, wherein the zinc alloy powder accounts for 70% to 90% of the zinc powder film material by mass.

[0010] Optionally, the mass content of the zinc alloy powder on the zinc powder film material is selected from any value among 70%, 75%, 80%, 85%, and 90%, or a range between any two of the above points.

[0011] According to another aspect of this application, a method for preparing the zinc powder film material described above is provided, the method comprising at least:

[0012] A mixture containing zinc alloy powder, flexible material, pore-forming agent, and additives is coated onto a substrate to obtain the zinc powder film material.

[0013] The flexible material is selected from at least one of polyvinylidene fluoride, polyvinylidene fluoride-copolymer-hexafluoropropylene, and polystyrene sulfonic acid-grafted polyvinylidene fluoride.

[0014] Optionally, the additives include bismuth pentoxide, zinc oxide, and tin dioxide.

[0015] Optionally, the mass ratio of the additive to the zinc alloy powder is 9:70 to 1:30.

[0016] Optionally, the additive may further include at least one of indium trioxide and sodium carboxymethyl cellulose.

[0017] Optionally, the mass ratio of the indium trioxide used to the zinc alloy powder is 1:70 to 1:90.

[0018] Optionally, the mass ratio of bismuth pentoxide to zinc alloy powder is 1:70 to 1:90.

[0019] Optionally, the ratio of the amount of zinc oxide used to the mass of zinc alloy powder is 1:10 to 1:90.

[0020] Optionally, the mass ratio of tin dioxide to zinc alloy powder is 1:70 to 1:90.

[0021] Optionally, the mass ratio of sodium carboxymethyl cellulose to zinc alloy powder is 1:70 to 1:90.

[0022] Optionally, both the adhesive and the film-forming agent are polyvinylidene fluoride.

[0023] Optionally, the mass ratio of the polyvinylidene fluoride to the zinc alloy powder is 1:7 to 1:30.

[0024] Optionally, the mass ratio of the polyvinylidene fluoride to the zinc alloy powder is selected from any value among 1:7, 1:10, 1:15, 1:20, 1:25, and 1:30, or a range between any two of the above.

[0025] Optionally, the pore-forming agent is selected from at least one of ammonium bicarbonate, sodium bicarbonate, and sodium carbonate.

[0026] Optionally, the mass ratio of the pore-forming agent to the zinc alloy powder is 1:10 to 1:30.

[0027] Optionally, the mass ratio of the pore-forming agent to the zinc alloy powder is selected from any value among 1:10, 1:15, 1:20, 1:25, and 1:30, or a range between any two of the above.

[0028] Optionally, the zinc alloy powder has a particle size of 250-500 mesh.

[0029] Optionally, the particle size of the zinc alloy powder is selected from any value among 250 mesh, 300 mesh, 350 mesh, 400 mesh, 450 mesh, and 500 mesh, or a range between any two of the above.

[0030] Optionally, the mixture may further include N-methylpyrrolidone, wherein the amount of N-methylpyrrolidone is 5 to 8 times the mass of the flexible material.

[0031] Optionally, the amount of N-methylpyrrolidone used is selected from any value of 5 times, 6 times, 7 times, or 8 times the mass of the flexible material, or a range between any two of the above.

[0032] Optionally, the blade spacing for the coating process is 100µm to 1500µm.

[0033] Optionally, the blade spacing for the coating is selected from any value among 100um, 500um, 1000um, and 1500um, or a range between any two of the above points.

[0034] Optionally, the substrate is selected from at least one of glass plate and stainless steel plate.

[0035] Optionally, the coating process on the substrate further includes drying, wherein the drying temperature is 60–80°C and the drying time is 6–12 hours.

[0036] Optionally, the drying temperature is selected from any value among 60℃, 65℃, 70℃, 75℃, and 80℃, or a range between any two of the above points.

[0037] Optionally, the drying time is selected from any value among 6h, 8h, 10h, and 12h, or a range between any two of the above.

[0038] According to another aspect of this application, a flexible zinc powder electrode is provided, the flexible zinc powder electrode being prepared from at least one of the zinc powder film material described above and the zinc powder film material prepared by the preparation method described above.

[0039] According to another aspect of this application, the above-described flexible zinc powder electrode is provided as a negative electrode in aqueous zinc-ion batteries and zinc-nickel secondary batteries.

[0040] As a specific implementation method, the present invention is achieved through the following technical solution:

[0041] The key to preparing the porous flexible zinc powder anode lies in controlling the proportions of various components. The specific preparation steps are as follows:

[0042] Weigh out appropriate proportions of zinc alloy powder, polyvinylidene fluoride (PVDF), ammonium bicarbonate, indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide, and sodium carboxymethyl cellulose. Mix them in a mortar and grind until homogeneous. Transfer the mixture to a beaker, then add N-methylpyrrolidone in an amount 5–8 times the amount of PVDF. Stir with a magnetic stirrer for 2 hours to form a homogeneous slurry. Transfer the prepared slurry to a clean glass or stainless steel plate and coat it using an adjustable-pitch doctor blade with a spacing of 100 μm–1500 μm. Finally, place the coated negative electrode film in a vacuum drying oven for drying.

[0043] Using the electrode prepared according to the above steps as the negative electrode, and employing glass fiber membrane (GF / C) and polypropylene microporous membrane as separators, respectively, and using 2 mol / L ZnSO4 solution with 0.2 mol / L MnSO4 added and KOH solution with 6 mol / L saturated ZnO as electrolytes, respectively, soft-pack batteries were assembled. The electrochemical performance of the prepared batteries was then tested using a LAND-CT2001A battery testing system.

[0044] Test results show that when the porous flexible zinc powder film anode prepared in this invention is used as the anode of a zinc-ion battery, it achieves a performance of 5 mA / cm². 2 Current density, 10 mAh / cm 2Under the given areal capacity condition, the charge-discharge cycle life can reach 300 hours. In full-cell tests using manganese dioxide as the positive electrode, the 800mAh-class battery achieved a charge-discharge cycle life of 31 cycles. When used as the negative electrode in a zinc-nickel secondary battery, in full-cell tests using nickel hydroxide as the positive electrode, the 100mAh-class battery achieved a charge-discharge cycle life of 400 cycles.

[0045] The porous flexible zinc powder film negative electrode obtained by this invention has a thickness of 50μm-200μm, a pore size of 30-300μm, and a porosity of 10%-30%, and is prepared by a scraping coating method.

[0046] The beneficial effects that this application can produce include:

[0047] 1) The raw materials used in this invention are inexpensive materials such as zinc alloy powder, ammonium bicarbonate, tin dioxide and bismuth pentoxide. The materials are widely available, green and safe, and low in cost.

[0048] 2) This invention uses a scraping coating method, which is simple and can achieve large-scale production.

[0049] 3) The membrane electrode obtained by the method of the present invention has a long cycle life. Attached Figure Description

[0050] Figure 1 Images of the porous flexible zinc powder film materials prepared in this application ((A) shows a zinc powder negative electrode film material with a thickness of 50 μm and a porosity of 30%; (B) shows a zinc powder negative electrode film material with a thickness of 200 μm and a porosity of 10%).

[0051] Figure 2 For this application, 5mA / cm -2 Discharge curves of zinc-zinc symmetric cells with porous flexible zinc powder film material and commercial zinc foil anode prepared at a current density.

[0052] Figure 3 This is a discharge curve of an 800mAh zinc-ion battery prepared in this application using the porous flexible zinc powder film material as the negative electrode and manganese dioxide as the positive electrode.

[0053] Figure 4 The discharge curve of the zinc-nickel battery composed of the prepared porous flexible zinc powder film material as the negative electrode and nickel hydroxide as the positive electrode is shown at a current density of 0.5C. Detailed Implementation

[0054] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0055] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0056] This invention relates to a method for preparing a porous flexible zinc powder negative electrode, comprising the following steps:

[0057] Weigh out the appropriate proportions of zinc alloy powder, polyvinylidene fluoride, ammonium bicarbonate, indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide, and sodium carboxymethyl cellulose. Mix them in a mortar and grind until homogeneous. Transfer the mixture to a beaker, then add N-methylpyrrolidone in an amount 5-8 times the amount of polyvinylidene fluoride. Stir with a magnetic stirrer for 2 hours to form a homogeneous slurry. Transfer the prepared slurry to a clean glass or stainless steel plate and coat it using an adjustable-pitch doctor blade with a spacing of 100μm-1500μm. Finally, place the coated negative electrode film in a vacuum drying oven for drying.

[0058] The polyvinylidene fluoride is used as a binder and film-forming agent, and its mass ratio with zinc alloy powder is 1:7-1:30.

[0059] The ammonium bicarbonate is a pore-forming agent, and the mass ratio of its usage to zinc alloy powder is 1:10-1:30.

[0060] The mass ratio of indium trioxide to zinc alloy powder is 1:70-1:90.

[0061] The mass ratio of bismuth pentoxide to zinc alloy powder is 1:70-1:90.

[0062] The ratio of zinc oxide usage to zinc alloy powder by mass is 1:10 to 1:90.

[0063] The mass ratio of tin dioxide used to zinc alloy powder is 1:70-1:90.

[0064] The mass ratio of sodium carboxymethyl cellulose used to zinc alloy powder is 1:70-1:90.

[0065] The vacuum drying temperature is 60–80°C, and the drying time is 6–12 hours.

[0066] Using the electrode prepared according to the above steps as the negative electrode, and employing glass fiber membrane (GF / C) and polypropylene microporous membrane as separators, respectively, and using 2 mol / L ZnSO4 solution with 0.2 mol / L MnSO4 added and KOH solution with 6 mol / L saturated ZnO as electrolytes, respectively, soft-pack batteries were assembled. The electrochemical performance of the prepared batteries was then tested using a LAND-CT2001A battery testing system.

[0067] Example 1

[0068] Weigh out 9g of zinc alloy powder with a particle size of 300 mesh, 0.5g of polyvinylidene fluoride, 0.9g of ammonium bicarbonate, 0.1g of indium trioxide, 0.1g of bismuth pentoxide, 0.1g of zinc oxide, 0.1g of tin dioxide, and 0.1g of sodium carboxymethyl cellulose. The polyvinylidene fluoride is used as a binder and film-forming agent, and its mass ratio to the zinc alloy powder is 1:18. The ammonium bicarbonate is used as a pore-forming agent, and its mass ratio to the zinc alloy powder is 1:10. The mass ratios of indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide, and sodium carboxymethyl cellulose to the zinc alloy powder are all 1:90. The mixture was ground in a mortar until homogeneous, then transferred to a beaker. 3g of N-methylpyrrolidone was added, six times the amount of polyvinylidene fluoride (PVDF). The mixture was then stirred with a magnetic stirrer for 2 hours to form a homogeneous slurry. The prepared slurry was then transferred to a clean glass or stainless steel plate and coated using an adjustable-pitch squeegee with a blade spacing of 200μm. The coated negative electrode was then placed in a vacuum drying oven at 60℃ for 6 hours to obtain a porous flexible zinc powder membrane material.

[0069] The porous flexible zinc powder membrane material prepared according to the above steps was used as the negative electrode, and glass fiber membrane (GF / C) was used as the separator. A 2 mol / L ZnSO4 solution with 0.2 mol / L MnSO4 added was used as the electrolyte to assemble a pouch cell. The prepared cells were then tested using a LAND-CT2001A battery testing system at 5 mA / cm². 2 Current density, 10 mAh / cm 2 Electrochemical performance was tested at the areal capacity.

[0070] Figure 1 (A) is a photograph of the prepared porous flexible zinc powder film negative electrode. It can be seen that the thickness of the film negative electrode is 50 μm; the pore size is 30-40 μm, the porosity is 30%, and it has the characteristics of flexibility and can be bent arbitrarily.

[0071] Figure 2 5mA / cm -2 The discharge curves of zinc-zinc symmetric cells using a porous flexible zinc powder film anode and a commercial zinc foil anode at a current density of [insert current density here]. The figures clearly show that the prepared porous flexible zinc powder film anode has a longer cycle life and better conductivity than the commercial zinc foil anode. At a current density of 10 mAh cm⁻¹... -2 Under the condition of areal capacity, it has a cycle life of 300h, while commercial zinc foil anodes only have 40h.

[0072] Figure 3 The figure shows the discharge curve of an 800mAh zinc-ion battery prepared using the prepared porous flexible zinc powder film material as the negative electrode and manganese dioxide as the positive electrode. As can be seen from the figure, the battery has a cycle life of 31 cycles at a current density of 0.05C, while batteries using commercial zinc foil negative electrodes typically only have a cycle life of 2-3 cycles.

[0073] Example 2

[0074] Weigh out 9g of zinc alloy powder with a particle size of 300 mesh, 0.5g of polyvinylidene fluoride, 0.3g of ammonium bicarbonate, 0.1g of indium trioxide, 0.1g of bismuth pentoxide, 0.1g of zinc oxide, 0.1g of tin dioxide, and 0.1g of sodium carboxymethyl cellulose. The polyvinylidene fluoride is used as a binder and film-forming agent, with a mass ratio of 1:18 to the zinc alloy powder. The ammonium bicarbonate is used as a pore-forming agent, with a mass ratio of 1:30 to the zinc alloy powder. The mass ratios of indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide, and sodium carboxymethyl cellulose to the zinc alloy powder are all 1:90. The mixture was ground in a mortar until homogeneous, then transferred to a beaker. 3g of N-methylpyrrolidone was added, six times the amount of polyvinylidene fluoride (PVDF). The mixture was then stirred with a magnetic stirrer for 2 hours to form a homogeneous slurry. The prepared slurry was then transferred to a clean glass or stainless steel plate and coated using an adjustable-pitch squeegee with a blade spacing of 1000μm. The coated negative electrode was then placed in a vacuum drying oven at 60℃ for 6 hours to obtain a porous flexible zinc powder membrane material.

[0075] The porous flexible zinc powder membrane material prepared according to the above steps was used as the negative electrode, and glass fiber membrane (GF / C) was used as the separator. A 2 mol / L ZnSO4 solution with 0.2 mol / L MnSO4 added was used as the electrolyte to assemble a pouch cell. The prepared cells were then tested using a LAND-CT2001A battery testing system at 5 mA / cm². 2 Current density, 10 mAh / cm 2 Electrochemical performance was tested at the areal capacity.

[0076] Figure 1 (B) is a photograph of the prepared porous flexible zinc powder film negative electrode. It can be seen that the thickness of the film negative electrode is 200 μm; the pore size is 30-40 μm, the porosity is 10%, and it has the characteristics of flexibility and can be bent arbitrarily.

[0077] Example 2 differs from Example 1 only in that the thickness of the porous flexible zinc powder film material is adjusted to 200 μm and the porosity to 10%. Electrochemical test results show that the performance of this porous flexible zinc powder film material is exactly the same as that in Example 1. This is because, within a certain range, the performance of this porous flexible zinc powder film material is independent of the film thickness and porosity.

[0078] Example 3

[0079] Weigh out 8g of 350-mesh zinc alloy powder, 0.5g of polyvinylidene fluoride (PVDF), 0.8g of ammonium bicarbonate, 0.1g of indium trioxide, 0.1g of bismuth pentoxide, 0.8g of zinc oxide, 0.1g of tin dioxide, and 0.1g of sodium carboxymethyl cellulose. PVDF is used as a binder and film-forming agent, with a mass ratio of 1:16 to the zinc alloy powder. Ammonium bicarbonate is used as a pore-forming agent, with a mass ratio of 1:10 to the zinc alloy powder. The mass ratios of indium trioxide, bismuth pentoxide, zinc oxide, tin dioxide, and sodium carboxymethyl cellulose are all 1:80 to the zinc alloy powder. The mixture was ground in a mortar until homogeneous, then transferred to a beaker. 4g of N-methylpyrrolidone was added, eight times the amount of polyvinylidene fluoride (PVDF). The mixture was then stirred with a magnetic stirrer for 2 hours to form a homogeneous slurry. The prepared slurry was then transferred to a clean glass or stainless steel plate and coated using an adjustable-pitch squeegee with a blade spacing of 200μm. The coated negative electrode was then placed in a vacuum drying oven at 60℃ for 6 hours to obtain a porous flexible zinc powder membrane material.

[0080] The porous flexible zinc powder membrane material prepared according to the above steps was used as the negative electrode, and a polypropylene microporous membrane was used as the separator. A KOH solution with 6 mol / L saturated ZnO was added as the electrolyte to assemble a pouch cell. The prepared cell was then tested using a LAND-CT2001A battery testing system at 5 mA / cm². 2 Current density, 10 mAh / cm 2 Electrochemical performance was tested at the areal capacity.

[0081] Example 3 differs from Example 1 only in the amount of zinc alloy powder and zinc oxide used. The discharge curve of a zinc-nickel battery using the prepared porous flexible zinc powder film material as the negative electrode and nickel hydroxide as the positive electrode at a current density of 0.5C is shown below. Figure 4As shown in the figure, the prepared battery has a cycle life of 400 cycles. In contrast, the unmodified zinc anode, which is a zinc anode with zinc oxide coated on a tin-plated copper mesh, typically has a cycle life of only a few dozen cycles.

[0082] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A zinc powder film material, characterized in that, The zinc powder film material is a flexible material with through-holes; the pore diameter of the zinc powder film material is 30~300um, and the porosity is 10%~30%; The thickness of the zinc powder film material is 50µm~200µm; The zinc powder film material includes zinc alloy powder, and the zinc alloy powder accounts for 70% to 90% of the zinc powder film material by mass. The method for preparing the zinc powder film material includes at least the following: A mixture containing zinc alloy powder, flexible material, pore-forming agent, and additives is coated onto a substrate to obtain the zinc powder film material. The flexible material is selected from at least one of polyvinylidene fluoride, polyvinylidene fluoride-copolymer-hexafluoropropylene, and polystyrene sulfonic acid-grafted polyvinylidene fluoride.

2. The method according to claim 1, characterized in that, The additives include bismuth pentoxide, zinc oxide, and tin dioxide.

3. The method according to claim 1, characterized in that, The mass ratio of the additive to the zinc alloy powder is 9:70 to 1:30; The additives also include at least one of indium trioxide and sodium carboxymethyl cellulose.

4. The method according to claim 1, characterized in that, The mass ratio of the flexible material to the zinc alloy powder is 1:7 to 1:30; The pore-forming agent is selected from at least one of ammonium bicarbonate, sodium bicarbonate, and sodium carbonate. The mass ratio of the pore-forming agent to the zinc alloy powder is 1:10 to 1:30; The zinc alloy powder has a particle size of 250~500 mesh.

5. The method according to claim 1, characterized in that, The mixture also includes N-methylpyrrolidone, the amount of which is 5 to 8 times the mass of the flexible material.

6. The method according to claim 1, characterized in that, The spacing between the scraper blades used for coating is 100um to 1500um.

7. The method according to claim 1, characterized in that, The substrate is selected from at least one of glass plate and stainless steel plate.

8. The method according to claim 1, characterized in that, The process of coating the substrate by scraping also includes drying, wherein the drying temperature is 60~80℃ and the drying time is 6~12 h.

9. A flexible zinc powder electrode, characterized in that, The flexible zinc powder electrode is prepared from at least one of the zinc powder film materials prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the flexible zinc powder electrode as a negative electrode in aqueous zinc-ion batteries and zinc-nickel secondary batteries, according to claim 9.

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