Preparation method and application of degradable aqueous zinc ion battery paper-based separator
By compositing halloysite nanotubes and chitosan onto a paper-based separator, the mechanical strength and ion transport issues of aqueous zinc-ion battery separators were resolved, resulting in a high-efficiency and environmentally friendly improvement in battery performance, making it suitable for commercial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV OF TECH SHENGZHOU INNOVATION RES INST CO LTD
- Filing Date
- 2025-01-24
- Publication Date
- 2026-05-29
AI Technical Summary
The glass fiber separators in existing aqueous zinc-ion batteries have poor mechanical properties, are prone to breakage, have insufficient ion transport performance, and are non-degradable, which affects the long-term stability and environmental friendliness of the batteries.
A paper-based diaphragm was modified with halloysite nanotubes and chitosan composite material. The mixture was ultrasonically dispersed and stirred to form a uniform coating, which improved the mechanical strength and ion transport performance of the diaphragm.
It enhances the mechanical strength and ion conduction performance of the separator, extends the cycle life of the battery, has good degradability, is environmentally friendly, simplifies the preparation process, and reduces costs.
Smart Images
Figure CN119944224B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of aqueous zinc-ion batteries, and more specifically relates to a method for preparing and applying a biodegradable paper-based separator for aqueous zinc-ion batteries. Background Technology
[0002] In recent years, the energy industry has achieved remarkable results in building a clean, low-carbon, safe, and efficient energy system. At the same time, the intermittent and discontinuous nature of clean energy sources such as wind and solar power has strongly promoted the growth in demand and development of large-scale energy storage technologies and equipment. Although lithium-ion batteries possess significant advantages such as high conversion efficiency and high energy density, the high cost of lithium and cobalt, their environmental hazards, and the stringent environmental requirements for battery manufacturing have limited their large-scale application. In recent years, aqueous zinc-ion batteries (ZIBs) have gained attention due to their safety, non-toxicity, and relatively high theoretical capacity (5854 mAh·cm³). -3 With its low redox potential (compared to -0.763V for the standard hydrogen electrode (ShE), it has become one of the most promising sustainable energy storage technologies.
[0003] Aqueous zinc-ion batteries typically consist of an anode, cathode, electrolyte, and separator. As an indispensable component, the separator is tightly connected to the electrodes, separating the anode and cathode to prevent short circuits. The morphology, structure, composition, and physical and chemical properties of the separator play a crucial role in the battery's long-lasting and excellent electrochemical performance. The performance stability of aqueous zinc-ion batteries largely depends on the combination of various parameters, which work synergistically to exert their effects. Glass fiber (GF), cellulose, and polymers are commonly used as raw materials for aqueous zinc-ion battery separators. However, commercially available glass fiber separators have poor mechanical properties, are prone to breakage or damage during battery charge-discharge cycles, and cannot meet the requirements for long-term use. Furthermore, commercially available glass fiber separators have insufficient ion transport performance, limiting battery performance. Moreover, their manufacturing and disposal processes pose environmental problems (such as non-degradability), necessitating the exploration of more suitable alternative materials.
[0004] Paper-based separators (such as filter paper, weighing paper, and commercial printing paper) are relatively environmentally friendly in terms of their manufacturing process and raw materials, thus possessing the potential to replace glass fiber separators. However, pure paper-based separators still have some drawbacks when used as battery separators: they have relatively weak mechanical strength, making them prone to breakage or damage during battery use, affecting the long-term stability of the battery; their pores are relatively large and unevenly distributed, resulting in relatively poor ion transport performance, which may limit the battery's rapid charge and discharge characteristics, requiring modification to improve their efficiency; and paper-based separators are difficult to maintain stability in harsh environments such as high temperature and high humidity, requiring further modification to enhance their durability and adaptability. Summary of the Invention
[0005] To address the aforementioned problems, this invention provides a simple, low-cost, and stable method for preparing a biodegradable paper-based separator for aqueous zinc-ion batteries. This invention involves uniformly adsorbing halloysite nanotubes onto a chitosan polymer chain network to form a composite material, which, when applied to a paper-based separator, helps improve zinc ion transport efficiency. Simultaneously, this separator possesses excellent mechanical strength, capable of withstanding volume changes in the zinc anode during battery cycling, maintaining its structural integrity, and further extending the battery's cycle life.
[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0007] First, this invention provides a method for preparing a biodegradable paper-based separator for aqueous zinc-ion batteries, comprising the following steps:
[0008] (1) Add halloysite nanotubes to water and disperse by ultrasonication to obtain halloysite nanotube suspension;
[0009] (2) Add glacial acetic acid, polyethylene glycol and chitosan to halloysite nanotube suspension, stir evenly to composite, and obtain composite slurry;
[0010] (3) The composite slurry is uniformly coated onto the surface of the paper-based separator, dried, and a coating is formed to obtain a biodegradable water-based zinc-ion battery paper-based separator.
[0011] In the above preparation method, the present invention first uses ultrasonic treatment to fully disperse halloysite nanotubes in water, further enhancing the surface activity of halloysite nanotubes and alleviating agglomeration; then, chitosan, which is natural and has abundant functional groups, is mixed with halloysite nanotubes to form a homogeneous composite slurry; finally, the composite slurry is coated on the surface of a paper-based separator, so that the composite material formed by chitosan and halloysite nanotubes is fully fixed on the paper fibers through physical adsorption, and after drying, a biodegradable aqueous zinc-ion battery paper-based separator is obtained.
[0012] Preferably, in step (1), the concentration of the halloysite nanotube suspension is 0.1 to 0.3 g / mL.
[0013] Preferably, in step (2), the mass ratio of chitosan to halloysite nanotubes is 1:(0.2-0.5).
[0014] This invention reveals that the mass ratio of chitosan to halloysite nanotubes is crucial. Insufficient chitosan may fail to adequately cover the filter paper fiber surface, resulting in insignificant modification effects and an inability to significantly improve the ion transport efficiency, mechanical strength, or chemical stability of the separator. Simultaneously, insufficient chitosan may not form an effective synergistic effect with halloysite nanotubes, failing to fully leverage their respective advantages in improving battery performance. Conversely, excessive chitosan will form an overly thick coating on the filter paper surface, blocking the original pore structure of the paper base material, making it difficult for the electrolyte to fully wet the separator, thereby reducing ion transport rate and conductivity. Therefore, in practical applications, it is necessary to strictly control the mass ratio of the two through optimized experiments to maximize battery performance. This ratio should ensure that chitosan can uniformly cover the surface of the paper base fiber and form a good synergistic effect with the halloysite nanotubes, while avoiding clogging the pore structure of the paper base material and retaining sufficient liquid absorption capacity.
[0015] Preferably, in step (2), the stirring conditions are stirring at 20-40°C for 3-24 hours.
[0016] Halloysite nanotubes, due to their high specific surface area and layered wall structure, tend to spontaneously aggregate in solution without treatment, forming large particles. This aggregation significantly reduces the effective specific surface area of the nanotubes, decreasing their dispersion uniformity in composite materials and thus affecting the overall performance of the composites. After uniform dispersion, mixing with chitosan promotes interfacial compatibility between the two through intermolecular forces.
[0017] Preferably, in step (3), the paper-based diaphragm is filter paper, weighing paper, or commercial printing paper.
[0018] Preferably, in step (3), the coating method is immersion, filtration, drop coating or spin coating.
[0019] Preferably, in step (3), the thickness of the coating is 20 to 80 μm.
[0020] Secondly, the present invention provides a biodegradable aqueous zinc-ion battery paper-based separator obtained by the above preparation method.
[0021] Finally, the present invention provides an aqueous zinc-ion battery, wherein the separator is the aforementioned biodegradable aqueous zinc-ion battery paper-based separator.
[0022] Compared with the prior art, the present invention has the following advantages:
[0023] (1) Compared to traditional commercial glass fiber, the paper-based material made from natural cellulose used in this invention as a separator for aqueous zinc-ion batteries exhibits excellent biodegradability and is more environmentally friendly. Furthermore, the paper-based material, with its softness and flexibility, is an ideal choice for flexible separator materials, overcoming the limitations of glass fiber in terms of flexibility. Economically, paper-based materials are less expensive, and the preparation process is relatively economical and efficient. More importantly, the excellent processing performance of the paper-based separator allows it to easily meet various process requirements such as cutting, folding, and molding, providing great convenience and flexibility for diverse preparation processes.
[0024] (2) Compared to modifying paper-based separators with single-component chitosan or halloysite nanotubes, the combination of the two to form a composite material offers significant advantages. Chitosan, rich in amino and hydroxyl groups, possesses excellent hydrophilicity and ion exchange capacity, enhancing the ion conductivity of the separator. Halloysite nanotubes, as layered silicate minerals, exhibit high ion adsorption capacity and excellent ion transport performance. When chitosan and halloysite nanotubes are combined to form a composite material, their synergistic effect optimizes chemical properties. Chitosan exhibits good biocompatibility and adhesion, allowing it to bond tightly with paper fibers, while the high ion adsorption capacity and ion transport performance of halloysite nanotubes further improve the selective permeability and ion conductivity of the separator surface. Furthermore, the combination of the two can form a more uniform ion transport channel, effectively blocking the growth and penetration of zinc dendrites, thus improving battery safety and cycle stability.
[0025] (3) Compared with ordinary disordered adsorption, this invention strictly controls the ratio of chitosan to halloysite nanotubes and limits the mixing time of the two, so that halloysite nanotubes can fully and uniformly combine with the network structure of chitosan and adhere to the paper fibers, promote the uniform diffusion of ions and optimize the electric field distribution on the surface of zinc negative electrode, and realize the uniform deposition of zinc ions on the negative electrode. This can effectively prevent the occurrence of "dead zinc" phenomenon, thereby alleviating the capacity decay problem of aqueous zinc-ion batteries during long-term cycling. In addition, chitosan is a natural polysaccharide obtained by deacetylation of chitin, which has good biocompatibility and degradability, and helps to reduce the potential harm of batteries to the environment and human health.
[0026] (4) When the chitosan-halothite nanotube composite material is used as a paper-based separator modification for aqueous zinc-ion batteries, this invention can enhance the separator's permeability, promote the rapid and uniform diffusion of ions in the electrolyte, reduce the formation of zinc dendrites, and improve the battery's charge and discharge efficiency. Simultaneously, a protective film can be formed on the outside of the separator to prevent short circuits and battery failures caused by zinc dendrites piercing the separator. Furthermore, this composite material can also improve the overall mechanical properties of the separator and enhance the stability and durability of the battery structure.
[0027] (5) Compared with existing reports on aqueous zinc-ion battery separator modification layers, this invention innovatively introduces a natural, environmentally friendly, and biodegradable separator material. Its significant advantages lie in its low raw material cost, complete elimination of the use of hazardous chemicals during production, greatly simplified operating procedures, and precise control over the content of the modifier. These advantages are of immeasurable importance in accelerating the commercial application of aqueous zinc-ion battery technology. Attached Figure Description
[0028] Figure 1 X-ray diffraction patterns of the membranes prepared in Comparative Example 1 and Example 1;
[0029] Figure 2 Scanning electron microscope image of the diaphragm prepared for Comparative Example 1;
[0030] Figure 3 A scanning electron microscope image of the diaphragm prepared in Example 1;
[0031] Figure 4 The AC impedance spectra of the membranes prepared in Comparative Example 1 and Example 1 are shown.
[0032] Figure 5 Tafel curves of the membranes prepared in Comparative Example 1 and Example 1;
[0033] Figure 6 For the symmetrical battery assembled using the separator prepared in Comparative Example 1, at 1 mA·cm -2 Current density and 1 mAh·cm -2 A diagram of the negative electrode deposition state after 120 hours of cycling at the desired deposition capacity;
[0034] Figure 7 For a symmetrical battery assembled using the separator prepared in Example 1, at 1 mA·cm -2 Current density and 1 mAh·cm -2 A diagram of the negative electrode deposition state after 120 hours of cycling at the desired deposition capacity;
[0035] Figure 8 For symmetrical cells assembled using the separators prepared in Comparative Examples 1, 2, and 1, at 1 mA·cm -2Current density and 1 mAh·cm -2 Voltage-time plots obtained at different deposition capacities; Detailed Implementation
[0036] The present invention will be further described in detail below with reference to the embodiments, and the technical content and effects thereof are not limited thereto.
[0037] Example 1
[0038] (1) Select qualitative filter paper with a thickness of 0.180 mm as the base material for paper-based diaphragms.
[0039] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 25 °C at a frequency of 75 kHz for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0040] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0041] (4) The filter paper was soaked in the composite solution prepared in step (3) at 40°C for 24 hours and dried to obtain a filter paper with chitosan and halloysite nanotube composite material.
[0042] (5) Cut the filter paper with chitosan and halloysite nanotube composite material into a diaphragm disc with a diameter of 1.6 cm.
[0043] Example 2
[0044] (1) Select qualitative filter paper with a thickness of 0.180 mm as the base material for paper-based diaphragms.
[0045] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 75 kHz at 25 °C for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0046] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0047] (4) The composite solution prepared in step (3) was spin-coated onto filter paper at 40°C and dried to obtain filter paper with chitosan and halloysite nanotube composite material.
[0048] (5) Cut the filter paper with chitosan and halloysite nanotube composite material into a diaphragm disc with a diameter of 1.6 cm.
[0049] Example 3
[0050] (1) Select qualitative filter paper with a thickness of 0.180 mm as the base material for paper-based diaphragms.
[0051] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 75 kHz at 25 °C for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0052] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0053] (4) The composite solution prepared in step (3) is coated onto filter paper at 40°C and dried to obtain filter paper with chitosan and halloysite nanotube composite material.
[0054] (6) Cut the filter paper with chitosan and halloysite nanotube composite material into a diaphragm disc with a diameter of 1.6 cm.
[0055] Example 4
[0056] (1) Weighing paper with a thickness of 0.080 mm is selected as the base material for the paper-based diaphragm.
[0057] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 25 °C at a frequency of 75 kHz for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0058] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0059] (4) The weighing paper was soaked in the composite solution prepared in step (3) at 40℃ for 24 hours and dried to obtain a weighing paper with chitosan and halloysite nanotube composite material.
[0060] (5) Cut the weighing paper with chitosan and halloysite nanotube composite material into a diaphragm disc with a diameter of 1.6 cm.
[0061] Example 5
[0062] (1) Commercial printing paper with a thickness of 0.260 mm was selected as the base material for the paper-based diaphragm.
[0063] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 25 °C at a frequency of 75 kHz for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0064] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0065] (4) Immerse the commercial printing paper in the composite solution prepared in step (3) at 40°C for 24 hours, and dry it to obtain the commercial printing paper with chitosan and halloysite nanotube composite material.
[0066] (5) Cut the above-mentioned commercial printing paper with chitosan and halloysite nanotube composite material into diaphragm discs with a diameter of 1.6 cm.
[0067] Example 6
[0068] (1) Commercial printing paper with a thickness of 0.080 mm was selected as the base material for the paper-based diaphragm.
[0069] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 25 °C at a frequency of 75 kHz for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0070] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0071] (4) The composite solution prepared in step (3) is scraped onto weighing paper at 40℃ and dried to obtain weighing paper with chitosan and halloysite nanotube composite material.
[0072] (5) Cut the above-mentioned commercial printing paper with chitosan and halloysite nanotube composite material into diaphragm discs with a diameter of 1.6 cm.
[0073] Comparative Example 1 (Pure Paper-Based Separator)
[0074] (1) Select qualitative filter paper with a thickness of 0.180 mm as the base material for paper-based diaphragms.
[0075] (2) Cut the filter paper diaphragm into diaphragm discs with a diameter of 1.6 cm.
[0076] Comparative Example 2 (Paper-based separator modified with a single component chitosan)
[0077] (1) Select qualitative filter paper with a thickness of 0.180 mm as the base material of the diaphragm.
[0078] (2) Add 0.1 mL of glacial acetic acid (HAc), 1.5 mL of polyethylene glycol (PEG) and 0.2 g of chitosan to 10 mL of deionized water, and stir and compound at 40 °C for 12 h to obtain a chitosan solution.
[0079] (3) The filter paper was soaked in the chitosan solution prepared in step (2) at 40°C for 24 hours and dried to obtain chitosan filter paper with a single component.
[0080] (4) Cut the chitosan filter paper with a single component into a diaphragm disc with a diameter of 1.6 cm.
[0081] Comparative Example 3 (Halloch nanotube composite material with reduced chitosan content based on Example 1)
[0082] (1) Select qualitative filter paper with a thickness of 0.180 mm as the base material for paper-based diaphragms.
[0083] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 75 kHz at 25 °C for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0084] (3) Add 0.05 mL of glacial acetic acid, 0.75 mL of polyethylene glycol and 0.1 g of chitosan to the suspension obtained in step (2), stir and combine at 40 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0085] (4) The filter paper was soaked in the composite solution prepared in step (3) at 40°C for 24 hours and dried to obtain a filter paper with chitosan and halloysite nanotube composite material.
[0086] (5) Cut the filter paper with chitosan and halloysite nanotube composite material into a diaphragm disc with a diameter of 1.6 cm.
[0087] Comparative Example 4 (Based on Example 1, but with a different composite temperature)
[0088] (1) Select qualitative filter paper with a thickness of 0.180 mm and a slow filtration speed as the material for the paper-based diaphragm.
[0089] (2) Add 300 mg of halloysite nanotubes to 10 mL of deionized water and stir for 24 h. Then sonicate at 25 °C at a frequency of 75 kHz for 15 min to completely disperse the halloysite nanotubes and obtain a halloysite nanotube suspension.
[0090] (3) Add 0.1 mL of glacial acetic acid, 1.5 mL of polyethylene glycol and 0.2 g of chitosan to the suspension obtained in step (2), stir and combine at 25 °C for 12 h to obtain a composite solution of halloysite nanotubes and chitosan.
[0091] (4) The filter paper was soaked in the composite solution prepared in step (3) at 25°C for 24 hours and dried to obtain a filter paper with chitosan and halloysite nanotube composite material.
[0092] (5) Cut the filter paper with chitosan and halloysite nanotube composite material into a diaphragm disc with a diameter of 1.6 cm.
[0093] Performance testing
[0094] The discs obtained in Examples 1-6 and Comparative Examples 1-4 were used as battery separators, and zinc sheets were used as the positive and negative electrodes of the battery. A 2.0 mol·L⁻¹ solution was used. -1 Zinc sulfate solution was used as the electrolyte to assemble a symmetrical battery. The assembled zinc-ion symmetrical battery was placed in a constant temperature environment of 25℃ for 2 hours and then subjected to an A·cm⁻¹ pressure. -2 Current density and 1 mAh·cm -2 Cyclic performance tests were conducted at the deposition capacity.
[0095] Table 1
[0096] Case Polarization voltage (V) Longest cycle time (h) Example 1 0.1 2000 Example 2 0.1 1500 Example 3 0.12 1800 Example 4 0.09 2000 Example 5 0.1 1800 Example 6 0.11 1600 Comparative Example 1 0.18 190 Comparative Example 2 0.12 1030 Comparative Example 3 0.15 860 Comparative Example 4 0.16 1000
[0097] As shown in Table 1, compared to the single-component chitosan modification in Comparative Example 2, the filter paper membrane co-modified with halloysite nanotubes and chitosan in Example 1 improved the diffusion rate of ions in the membrane, resulting in a longer cycle life and lower polarization voltage. The addition of a small amount of chitosan in Comparative Example 3 and the alteration of the composite temperature in Comparative Example 4 affected the uniformity of their combination, leading to a decrease in zinc ion transport efficiency and thus significantly impacting the battery's cycle performance.
[0098] Depend on Figure 1 It can be seen that strong peaks of dendritic byproducts appeared in the X-ray diffraction peaks of the pure filter paper after cycling (Comparative Example 1), while there were no such peaks in the filter paper membrane modified with halloysite nanotubes and chitosan (Example 1). This indicates that the modification layer can suppress the formation of dendritic byproducts on the zinc anode during battery cycling and protect the membrane from corrosion or dendrite puncture.
[0099] Depend on Figure 2It can be seen that the pure filter paper diaphragm (Comparative Example 1) is composed of many fibers of different sizes and thicknesses, and the pores on the surface are large and unevenly distributed.
[0100] Depend on Figure 3 As can be seen, the filter paper membrane (Example 1) modified with chitosan and halloysite nanotubes has a very smooth surface. Chitosan uniformly fixes the halloysite nanotubes on the surface of the filter paper fibers, which improves the large pore structure of the pure filter paper and is conducive to guiding uniform zinc deposition.
[0101] Depend on Figure 4 It can be seen that the interfacial impedance of the pure filter paper membrane (Comparative Example 1) reaches more than 1200Ω, indicating that the electrolyte / electrode interface is very unstable at this time. This is related to the accumulation of by-products and the growth of zinc dendrites. In contrast, the filter paper membrane modified with chitosan and halloysite nanotubes (Example 1) shows a smaller interfacial impedance, indicating that the filter paper modification layer weakens the interfacial effect.
[0102] Depend on Figure 5 It can be seen that, in the three-electrode system test of the corrosion resistance of zinc sheets under different diaphragms, the corrosion potential of the Zn electrode measured in the filter paper diaphragm modified with chitosan and halloysite nanotubes (Example 1) was -0.01V, which is positive compared to -0.019V measured in the pure filter paper diaphragm (Comparative Example 1).
[0103] Depend on Figure 6 It can be seen that after 120 minutes of cycling, a large number of non-uniform thin sheets were formed on the surface of the pure zinc sheet under the pure filter paper diaphragm (Comparative Example 1), and a large number of by-products were generated.
[0104] Depend on Figure 7 It can be seen that after 120 min of cycling, the filter paper membrane (Example 1) modified with chitosan and halloysite nanotubes exhibits a dendrite-free, uniform, and dense zinc deposition layer.
[0105] Depend on Figure 8 It can be seen that when the filter paper modified with halloysite nanotubes and chitosan proposed in this invention is used as the separator of an aqueous zinc-ion battery, the battery cycle stability is significantly improved, and it can operate stably for 2000 hours. The overpotential of zinc deposition / stripping is significantly reduced, and it exhibits less electrode polarization. The single-component chitosan-modified separator suffers from the aforementioned problems such as uneven ion diffusion and by-product accumulation, resulting in increasingly larger polarization and short circuits around 1030 hours. The unmodified filter paper separator causes a short circuit after 190 hours of cycling due to zinc dendrites piercing the separator.
[0106] The above embodiments of the present invention are merely illustrative examples and are not intended to limit the implementation of the invention. Those skilled in the art can make other variations and modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.
Claims
1. A method for preparing a biodegradable aqueous zinc-ion battery paper-based separator, characterized in that, Includes the following steps: (1) Add halloysite nanotubes to water and disperse by ultrasonication to obtain halloysite nanotube suspension; (2) Add glacial acetic acid, polyethylene glycol and chitosan to halloysite nanotube suspension, stir evenly to obtain composite slurry; the mass ratio of chitosan to halloysite nanotube is 1:(0.2~0.5); the stirring conditions are 20~40 ℃ for 3~24 h; (3) The composite slurry is uniformly coated onto the surface of the paper-based separator and dried to form a coating with a thickness of 20~80 μm, thus obtaining a biodegradable water-based zinc-ion battery paper-based separator.
2. The preparation method according to claim 1, characterized in that, In step (1), the concentration of the halloysite nanotube suspension is 0.1~0.3 g / mL.
3. The preparation method according to claim 1, characterized in that, In step (3), the paper-based diaphragm is filter paper, weighing paper, or commercial printing paper.
4. The preparation method according to claim 1, characterized in that, In step (3), the coating method is immersion, filtration, drop coating or spin coating.
5. A biodegradable aqueous zinc-ion battery paper-based separator obtained by the preparation method according to any one of claims 1-4.
6. The application of the biodegradable aqueous zinc-ion battery paper-based separator as described in claim 5 in aqueous zinc-ion batteries.