Separator for zinc ion battery, method for preparing same, and zinc ion battery comprising same

Abstract

The invention discloses a diaphragm of a zinc ion battery, a method for preparing the diaphragm and the zinc ion battery comprising the diaphragm. Specifically disclosed is a separator for a zinc ion battery, the separator comprising a separator matrix comprising a fibrous material and a filler dispersed in the fibrous material in the form of particles, the filler being an ammonium phosphate salt.

Description

Technical Field

[0001] This invention relates to the field of zinc-ion batteries, and more specifically, to a separator for zinc-ion batteries, a method for preparing the separator, and a zinc-ion battery comprising the separator. Background Technology

[0002] Aqueous zinc-ion batteries have attracted the attention of energy researchers and developers due to their high safety and low cost. However, zinc-ion batteries suffer from short circuits caused by zinc dendrite penetration and contact with the positive electrode material, necessitating the use of thicker separators to prevent this. Thicker separators reduce the energy density of zinc-ion batteries, negatively impacting their performance. Existing zinc-ion battery separator materials include: glass fiber, which suffers from low tensile strength, easy pulverization and dissolution after soaking in acidic, alkaline, or neutral solutions, and high cost; Celgard separators, based on polymers such as polypropylene and polyethylene, which have poor wettability, leading to fiberization when zinc dendrites contact the fabric, increasing separator porosity, damaging the separator structure, causing functional failure, and ultimately resulting in short circuits; and non-woven fabrics, which have good wettability but also suffer from fiberization due to zinc dendrites contacting the fabric, ultimately leading to short circuits. Therefore, none of the existing zinc-ion battery separator materials can solve the problems of zinc dendrite growth and penetration without affecting battery performance.

[0003] Given the aforementioned problems, it is necessary to develop a separator for zinc-ion batteries that can prevent zinc dendrite puncture with a relatively low thickness. Summary of the Invention

[0004] The main objective of this invention is to provide a separator for a zinc-ion battery, a method for preparing the separator thereon, and a zinc-ion battery containing the separator thereon, in order to solve the problem that the separator of a zinc-ion battery in the prior art is too thick in order to prevent zinc dendrite puncture, which leads to a decrease in battery performance.

[0005] Another objective of this invention is to provide a separator for a zinc-ion battery, a method for preparing the separator thereon, and a zinc-ion battery containing the separator thereon, in order to solve the problems of poor flexibility and / or wettability of the separator in the prior art, easy dissolution after soaking in acidic, alkaline, or neutral solutions, and high cost.

[0006] To achieve the above objectives, according to one aspect of the present invention, a separator for zinc-ion batteries is provided, the separator comprising a separator matrix containing fibrous material and a filler dispersed in the fibrous material in particulate form, the filler being an ammonium phosphate salt.

[0007] Furthermore, the fibrous material is paper, non-woven fabric, or glass fiber, preferably kitchen paper.

[0008] Furthermore, the filler is ammonium polyphosphate, diammonium hydrogen phosphate, ammonium phosphate trihydrate, or any combination thereof.

[0009] Furthermore, the filler loading in the fiber material is 0.001-0.25 mg / cm³. 2 The preferred concentration is 0.005-0.015 mg / cm³. 2 .

[0010] Furthermore, the porosity of the fiber material is 2.5-60%.

[0011] Furthermore, the average particle size of the filler particles is 0.5-2.5 μm.

[0012] Another aspect of the present invention provides a method for preparing a separator for a zinc-ion battery according to the above-described aspects of the present invention, comprising the following steps:

[0013] 1) Prepare the filler into a suspension;

[0014] 2) Cover the membrane substrate with a filter screen;

[0015] 3) Coating the suspension onto the membrane matrix covering the filter screen;

[0016] 4) Remove the filter.

[0017] Furthermore, the concentration of the packing material suspension is 0.1-5 mg / mL, preferably 0.2-0.5 mg / mL.

[0018] Another aspect of the present invention provides a zinc-ion secondary battery, comprising: a positive electrode, a negative electrode, an electrolyte, and a separator for a zinc-ion battery according to the above-described aspects of the present invention.

[0019] Furthermore, the positive electrode active material includes manganese oxide, vanadium oxide, manganese-vanadium oxide, a complex formed by vanadium oxide and an organic ligand, a metal element or ammonium, an organic positive electrode material, MXene-type materials or any combination thereof; and / or the negative electrode active material includes metallic zinc or zinc alloy; and / or the electrolyte contains zinc salt.

[0020] Furthermore, the positive electrode active material is manganese dioxide, the negative electrode active material includes metallic zinc, and the electrolyte contains manganese sulfate and zinc sulfate.

[0021] By applying the technical solution of this invention, by dispersing particulate ammonium phosphate filler in the fiber material of the separator used in zinc-ion batteries, the growth of zinc metal dendrites in zinc-ion batteries can be effectively suppressed, thereby allowing the use of separators with lower thickness and improving the performance of zinc-ion batteries. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a graph showing the cycle performance of the zinc-ion battery prepared in Example 1.

[0024] Figure 2 This is a graph showing the cycle performance of the zinc-ion battery prepared in Example 3.

[0025] Figure 3 This is a graph showing the cycle performance of the zinc-ion battery prepared in Comparative Example 1.

[0026] Figure 4 This is a graph showing the cycle performance of the zinc-ion battery prepared in Comparative Example 2. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0028] As explained in the background section, existing zinc-ion battery separators suffer from drawbacks such as excessive thickness to prevent zinc dendrite penetration, leading to decreased battery performance, poor flexibility and / or wettability, easy dissolution after immersion in acidic, alkaline, or neutral solutions, and high cost. To address these issues, this application provides a separator for zinc-ion batteries comprising a separator matrix containing fibrous material and a filler, specifically an ammonium phosphate salt, dispersed in the fibrous material in particulate form.

[0029] In this invention, by dispersing particulate ammonium phosphate filler in the fibrous material of the separator for zinc-ion batteries, the growth of zinc metal dendrites in the zinc-ion battery can be effectively suppressed, thereby allowing the use of a thinner separator and improving the performance of the zinc-ion battery, such as extending the cycle life and improving capacity retention. Specifically, using ammonium phosphate as the filler in the zinc-ion battery separator allows phosphate ions to effectively suppress the growth of zinc metal dendrites, and ammonium ions to moderately release the acidic environment, suppressing the decrease in pH in the zinc-ion battery, thereby suppressing the dissolution loss of positive electrode materials such as MnO2. Ammonium phosphate also acts as a flame retardant in the separator, improving battery safety. Furthermore, dispersing ammonium phosphate in particulate form in the fibrous material effectively reduces the porosity of the fibrous material separator, thereby preventing zinc ions from dissolving in the separator and increasing the contact area between the metal and the separator, resulting in a more uniform dispersion of electrolyte salt concentration.

[0030] In a preferred embodiment, the fibrous material is paper, nonwoven fabric, or glass fiber, preferably kitchen paper.

[0031] The separator of this invention can use known fibrous separator materials such as nonwoven fabric or glass fiber. As mentioned above, the ammonium phosphate filler dispersed therein in particulate form can effectively suppress the growth of zinc metal dendrites, thereby allowing the use of a thinner separator and improving the performance of zinc-ion batteries. Preferably, this invention proposes using paper materials such as kitchen paper as the separator material. Paper materials such as kitchen paper are mature commercial products with low cost and good flexibility and wettability, allowing the electrolyte components to be evenly dispersed in the electrolyte solution without clumping, and easy to adhere to the positive and negative electrode surfaces. In addition, kitchen paper has a highly ordered textured surface, which is more conducive to achieving uniform filling of the filler during the filler coating process. Therefore, using the above-mentioned material as the separator is more beneficial to improving the performance of zinc-ion batteries.

[0032] In a preferred embodiment, the filler is ammonium polyphosphate, diammonium hydrogen phosphate, ammonium phosphate trihydrate, or any combination thereof.

[0033] Those skilled in the art will understand that the ammonium phosphate filler of the present invention can be any ammonium phosphate filler suitable for zinc-ion batteries. In the examples provided below, the filler is ammonium polyphosphate ((NH4PO3)). n When diammonium hydrogen phosphate ((NH4)2HPO4, CAS: 7783-28-0), ammonium phosphate trihydrate ((NH4)3PO4·3H2O, CAS: 25447-33-0) or any combination thereof are used, they are more conducive to improving the performance of zinc-ion batteries.

[0034] In a preferred embodiment, the filler loading in the fiber material is 0.001-0.25 mg / cm³. 2 The preferred concentration is 0.005-0.015 mg / cm³. 2 .

[0035] If the filler loading is too low, the improvement in battery performance may be insufficient; if the loading is too high, the filler may be unevenly distributed on the separator surface, leading to unstable separator loading and decreased consistency. Therefore, a filler loading within the aforementioned range is more beneficial for improving the performance of zinc-ion batteries.

[0036] In a preferred embodiment, the porosity of the fiber material is 2.5-60%.

[0037] In a preferred embodiment, the average particle size of the filler particles is 0.5-2.5 μm.

[0038] As described above, in this invention, ammonium phosphate filler is dispersed in particulate form within the fibrous material separator. The particulate form of ammonium phosphate effectively reduces the porosity of the fibrous material separator. Preferably, when the porosity of the fibrous material is within the aforementioned range, it is more beneficial to improve the performance of the zinc-ion battery. For particulate fillers, a particle size within a specific range is more beneficial to improving the performance of the zinc-ion battery. Specifically, if the filler particle size is too small, it may not be able to effectively fill the base membrane and may scatter throughout the battery structure, or even cover the surface of the positive electrode, which is detrimental to improving battery capacity. If the filler particle size is too large, the filler may only remain on the surface of the base membrane and cannot penetrate into the voids of the substrate, resulting in an uneven separator surface, unstable separator loading, poor consistency, and difficulty in achieving uniform zinc deposition.

[0039] According to another aspect of the present invention, a method for preparing the above-described separator for zinc-ion batteries is provided, the method comprising the following steps:

[0040] 1) Prepare the filler into a suspension;

[0041] 2) Cover the membrane substrate with a filter screen;

[0042] 3) Coating the suspension onto the membrane matrix covering the filter screen;

[0043] 4) Remove the filter.

[0044] The method for preparing a separator for zinc-ion batteries according to the present invention uses a wet coating process with a suspension of filler material. Because a suspension of filler material is used, some of the undissolved filler particles can be dispersed throughout the separator matrix. Uniform coating of the separator is achieved by covering the separator matrix with a filter screen (preferably a 200-1000 mesh stainless steel mesh) with uniformly distributed pores on the filter screen. After coating, removing the filter screen allows excess filler to be carried away with it.

[0045] In a preferred embodiment, the concentration of the filler suspension is 0.1-5 mg / mL, preferably 0.2-0.5 mg / mL.

[0046] When the concentration of the filler suspension is within a specific range, it is more beneficial to improve the performance of zinc-ion batteries. Specifically, when the suspension concentration is too low, the filler suspension experiences sedimentation loss, and insufficient filler is added to the separator, resulting in a larger separator porosity and a relatively poor effect on preventing zinc dendrite penetration into the separator. When the solution concentration is too high, too many filler particles are added to the separator, which may form large, protruding particles on the separator surface, leading to an uneven separator surface.

[0047] According to another aspect of the present invention, a zinc-ion secondary battery is provided, comprising: a positive electrode, a negative electrode, an electrolyte, and the above-described separator for the zinc-ion battery.

[0048] In a preferred embodiment, the positive electrode active material includes manganese oxide, vanadium oxide, manganese-vanadium oxide, a complex formed by vanadium oxide and an organic ligand, a metal element or ammonium, an organic positive electrode material, MXene-type materials or any combination thereof; and / or the negative electrode active material includes metallic zinc or a zinc alloy; and / or the electrolyte contains zinc salts.

[0049] The separator of this invention is applicable to various zinc-ion battery positive electrode, negative electrode, and electrolyte materials known in the art. The positive electrode active material can be manganese oxide (Mn). x O y For example, MnO, MnO2, Mn2O3, Mn3O 4、 At least one of Mn5O8; vanadium oxide V x O y For example, VO, VO2, V3O5, V3O8, V5O 12 At least one of the following: vanadium metal; manganese vanadium oxide (Mn) x V2O5·nH2O, for example, Mn 0.15 V₂O₅·nH₂O; vanadium oxides containing organic ligands, metals, or ammonium intercalations, such as Org x V y O z ·nH2O (Org represents organic ligand), Mn x V y O z ·nH2O、K x V y O z ·nH2O, Ca x V y O z ·nH2O, Na x V y O z ·nH2O, Mg x V y O z ·nH2O, Al x V y O z ·nH2O、S x V y O z · nH2O、(NH4) x V y O zAt least one of nH2O; organic materials, such as metal-organic frameworks (MOFs), conjugated organic frameworks (COFs), Prussian blue, and Prussian white; polymers, such as polyaniline, polypyrrole, and polythiophene; MXene-like materials, such as Ti3C2T x The negative electrode active material can be a zinc metal material, such as at least one of zinc foil, zinc plate, zinc mesh, and zinc powder; or a zinc-containing alloy material, such as at least one of zinc-copper alloy and zinc-silver alloy. The electrolyte can be a zinc salt, such as at least one of zinc sulfate, zinc chloride, zinc phosphate, and zinc trifluoromethanesulfonate. The electrolyte may contain additives, which are at least one of organic additives and salt additives.

[0050] In a preferred embodiment, the positive electrode active material is manganese dioxide, the negative electrode active material includes metallic zinc, and the electrolyte contains manganese sulfate and zinc sulfate. The addition of manganese ions to the electrolyte serves to replenish manganese and inhibit manganese dissolution. Replenishing manganese is done to improve the structural stability and electrochemical performance of the manganese-based positive electrode material. Introducing manganese sulfate as an additive into the electrolyte can improve the specific capacity, rate performance, and long-term stability of the zinc-ion battery. This additive helps maintain the crystallinity and crystal structure of the positive electrode material and alleviates the dissolution of manganese in aqueous solution, thereby improving the cycle stability and electrochemical performance of the battery. Inhibiting manganese dissolution is done to reduce the dissolution of the positive electrode material during charge and discharge, extending the battery's cycle life. Manganese dissolution leads to the loss of active materials, increases electrolyte turbidity, and affects battery performance and safety. By optimizing the electrolyte composition and using additives, manganese dissolution can be inhibited, improving battery stability and lifespan. In summary, the purpose of replenishing manganese in the electrolyte and inhibiting manganese dissolution is to improve the electrochemical performance, cycle stability, and long-term performance of zinc-ion batteries, and to address the challenges faced by manganese-based cathode materials in battery applications. By optimizing the electrolyte and using additives, the manganese dissolution problem can be mitigated, thereby improving the overall performance of the battery.

[0051] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0052] Example

[0053] Zinc-ion batteries were prepared in the following examples.

[0054] Preparation of positive electrode sheet

[0055] Commercial nano-manganese dioxide, conductive agent and binder are used in a weight ratio of 8 / 1 / 1. Among them, α-phase nano-manganese dioxide (Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.) is selected as the positive electrode active material, BP2000 (Carbot) or C45 conductive carbon black is used as the conductive agent, and polyvinylidene fluoride (PVDF) (Solvey) is used as the binder.

[0056] 2.1 kg of PVDF was dissolved in N-methylpyrrolidone (NMP) solvent to prepare a 10.5% PVDF solution. Then, 16.8 kg of ground, dried manganese dioxide nanoparticles were added, and the mixture was stirred and degassed using a homogenizer until homogeneous and non-agglomerated. Subsequently, 2.1 kg of conductive agent BP2000 was added, and the mixture was stirred and degassed using a homogenizer until it was evenly dispersed. Then, NMP solvent was added to dilute the solution to a solid content of 40.93 wt% to 47.13 wt%, and the mixture was stirred and degassed again until it reached a flowable slurry.

[0057] The slurry was then coated onto a SUS304 stainless steel foil current collector and dried in a 90°C oven for 5 minutes to obtain the positive electrode sheet.

[0058] Preparation of negative electrode sheet

[0059] 20-micron zinc foil was used directly as the negative electrode.

[0060] Preparation of electrolyte

[0061] Prepare 1000 ml of a 2 M ZnSO4 - 0.05 M MnSO4 aqueous solution.

[0062] Preparation of diaphragm

[0063] Prepare a suspension of ammonium polyphosphate in water. Cover a sheet of kitchen paper with a stainless steel mesh (mesh size can be 24-50 mesh, 50-200 mesh, 200-5000 mesh, preferably 50-200 mesh). Add 20 μL of the ammonium polyphosphate suspension dropwise onto the kitchen paper and coat it using a scraping method, allowing the membrane substrate to fully absorb the moisture. Let it air dry naturally, then remove the stainless steel mesh. Hot-press the membrane substrate at 80°C to form a membrane. The membrane thickness is 43 μm.

[0064] Battery assembly

[0065] The negative electrode battery casing, negative electrode sheet, and filler membrane are assembled sequentially, and 60 μl of electrolyte is added. Then, the positive electrode sheet, gasket, spring sheet, and positive electrode battery casing are assembled sequentially. The assembly is transferred to a sealing machine, sealed, and left to stand for 30 minutes to produce a 2032 button cell battery for battery performance testing.

[0066] Battery performance test

[0067] The battery was charged and discharged on the Xinwei channel to test its capacity. The constant current discharge was set at 200 mA / g, the constant current charge at 200 mA / g, the discharge was followed by the charge, and the voltage range was 0.8-1.8 V.

[0068] Example 1

[0069] Following the steps described above, membranes and zinc-ion batteries were prepared using different filler suspension concentrations, as shown in Examples 1-1 to 1-7 in Table 1 below.

[0070] Example 2

[0071] Following the steps described above, membranes and zinc-ion batteries were prepared using different types of fillers, as shown in Examples 2-1 and 2-2 in Table 1 below.

[0072] Example 3

[0073] The difference from Example 1 is that glass fiber (commercially available Whatman GF / A separator) was used to prepare the zinc-ion battery, as shown in Table 1 below.

[0074] Example 4

[0075] The difference from Example 1 is that the packing loading is 0.001-0.25 mg / cm³. 2 Outside of the range, the concentration of the packing material suspension is outside the range of 0.1-5 mg / mL, see Examples 4-1 and 4-2 in Table 1 below.

[0076] Example 5

[0077] The difference from Example 1 is that a nonwoven fabric was used as the separator material to prepare the zinc-ion battery, as shown in Table 1 below. The nonwoven fabric is BEMCOT. ® Cleanroom wiping cloths (Ozu Sangyo), made of 70% long-fiber cellulose + 30% long-fiber polyester.

[0078] Table 1

[0079]

[0080] Battery performance tests were conducted on the zinc-ion battery samples from the above embodiments, and the results are shown in Table 2 and... Figure 1-2 .

[0081] Table 2

[0082]

[0083] *: Capacity retention rate (%) = Discharge capacity at 100th cycle / Maximum discharge specific capacity x 100%

[0084] Comparative Example 1

[0085] The difference from Example 1 is that no filler is added to the diaphragm, as shown in Table 3 below.

[0086] Comparative Example 2

[0087] The difference from Example 1 is that carboxymethyl cellulose (CMC) and ammonium polyphosphate (APP) were used as raw materials to prepare a cellulose-type zinc-ion battery separator, as shown in Table 3 below. The specific steps for separator preparation are as follows: 2.00 g of CMC was dissolved in 90 mL of deionized water and stirred for 30 min. 10.00 mL of an APP aqueous solution with a volume fraction of 5 mg / mL was added dropwise, and the mixture was stirred for another 30 min. The prepared CMC-APP aqueous solution was ultrasonically degassed for 30 min and allowed to gel at room temperature for 3 days. The CMC-APP hydrogel sheet was pre-frozen at -20°C and then freeze-dried at -20°C for 24 h to obtain a CMC-APP aerogel sheet with a thickness of 1.2 mm. Subsequently, the sheet was rolled to a film thickness of 0.2 mm. Finally, it was cut into separators with a diameter of 16 mm using a slicer. In this separator, ammonium polyphosphate forms a component of the separator matrix, rather than being dispersed in the separator matrix in particulate form.

[0088] Comparative Example 3

[0089] The difference from Comparative Example 1 is that non-woven fabric was used as the separator material to prepare the zinc-ion battery, as shown in Table 3 below.

[0090] Comparative Example 4

[0091] The difference from Comparative Example 1 is that glass fiber was used as the separator material to prepare the zinc-ion battery, as shown in Table 3 below.

[0092] Table 3

[0093]

[0094] The zinc-ion battery samples of the above comparative examples were tested for battery performance, and the results are shown in Table 4 and 5. Figure 3-4 .

[0095] Table 4

[0096]

[0097] Among them, the battery sample of Comparative Example 1 experienced a short circuit before reaching 100 charge-discharge cycles, so no data on the specific capacity and capacity retention rate at the 100th discharge cycle were obtained.

[0098] The test results show that the above embodiments of the present invention achieve the following technical effects:

[0099] By comparing Examples 1-1 to 1-7 with Comparative Examples 1, 5 and 3, and 3 and 4, it can be seen that the separator for zinc-ion batteries of the present invention, comprising a membrane matrix containing fibrous material and ammonium phosphate filler dispersed in particulate form in the fibrous material, improves the capacity performance of zinc-ion batteries compared to separators without ammonium phosphate filler. In Comparative Example 1, the battery experienced a short circuit at the 70th cycle of the cycle test. See [link to relevant documentation]. Figure 3 Furthermore, Comparative Example 4 exhibits better initial discharge capacity and maximum discharge capacity than Example 3, likely because the filler material may slow ion transport, resulting in a relatively low initial capacity. However, as cycling progresses, Example 3 demonstrates significantly better capacity retention than Comparative Example 4.

[0100] By comparing Examples 1-3 and Comparative Example 2, it can be seen that, under the same filler dosage, the separator for zinc-ion batteries of the present invention, which contains a membrane matrix with fibrous material and ammonium phosphate filler dispersed in the fibrous material in particulate form, improves the capacity performance of zinc-ion batteries compared to cellulose-type separators containing ammonium phosphate dissolved therein.

[0101] By comparing Examples 1-2 and 3, and Examples 1-3 and 5 respectively, it can be seen that, under the same filler dosage, using preferred kitchen paper as the separator matrix is ​​beneficial to further improve the capacity performance of zinc-ion batteries.

[0102] Comparison of Examples 1-1 to 1-7 (especially Examples 1-2 and 1-3) and Examples 4-1 and 4-2 shows that when the filler loading in the fiber material is 0.001-0.25 mg / cm³, 2 The preferred concentration is 0.005-0.015 mg / cm³. 2 When the concentration of the filler suspension is 0.1-5 mg / mL, preferably 0.2-0.5 mg / mL, it is beneficial to further improve the capacity performance of the zinc-ion battery.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 separator for a zinc-ion battery, the separator comprising a separator matrix containing fibrous material and a filler dispersed in the fibrous material in particulate form, characterized in that, The filler is an ammonium phosphate salt.

2. The separator for zinc-ion batteries according to claim 1, characterized in that, The fiber material is paper, non-woven fabric, or glass fiber, preferably kitchen paper.

3. The separator for zinc-ion batteries according to claim 1 or 2, characterized in that, The filler is ammonium polyphosphate, diammonium hydrogen phosphate, ammonium phosphate trihydrate, or any combination thereof.

4. The separator for zinc-ion batteries according to claim 1 or 2, characterized in that, The filler loading in the fiber material is 0.001-0.25 mg / cm³. 2 The preferred concentration is 0.005-0.015 mg / cm³. 2 .

5. The separator for zinc-ion batteries according to claim 1 or 2, characterized in that, The porosity of the fiber material is 2.5-60%.

6. The separator for zinc-ion batteries according to claim 1 or 2, characterized in that, The average particle size of the filler particles is 0.5-2.5 μm.

7. A method for preparing a separator for a zinc-ion battery according to any one of claims 1 to 6, characterized in that, The method includes the following steps: 1) Prepare the filler into a suspension; 2) Cover the membrane substrate with a filter screen; 3) Coating the suspension onto the membrane matrix covering the filter screen; 4) Remove the filter.

8. The method according to claim 7, characterized in that, The concentration of the suspension of the filler is 0.1-5 mg / mL, preferably 0.2-0.5 mg / mL.

9. A zinc-ion battery, characterized in that, include: positive electrode, negative electrode, Electrolyte, and The separator for zinc-ion batteries according to any one of claims 1 to 6.

10. The zinc-ion battery according to claim 9, characterized in that, The positive electrode active material includes manganese oxide, vanadium oxide, manganese-vanadium oxide, a complex formed by vanadium oxide and organic ligands, metal elements or ammonium, organic positive electrode material, MXene-type material or any combination thereof; and / or the negative electrode active material includes metallic zinc or zinc alloy; and / or the electrolyte contains zinc salt.

11. The zinc-ion battery according to claim 9, characterized in that, The positive electrode active material is manganese dioxide, the negative electrode active material includes metallic zinc, and the electrolyte contains manganese sulfate and zinc sulfate.

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