Zinc negative electrode containing electrostatic spinning composite hydrogel protective layer as well as preparation method and application of zinc negative electrode
By preparing a composite protective layer of electrospun polyacrylonitrile nanofibers and hydrogel, the problems of dendrite growth and corrosion of zinc anodes were solved, improving the cycle stability and battery safety of zinc anodes, and making it suitable for the industrial production of aqueous zinc-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN TEXTILE UNIV
- Filing Date
- 2026-01-15
- Publication Date
- 2026-04-17
AI Technical Summary
Existing electrospun protective layers on zinc anodes suffer from insufficient density, low ionic conductivity, poor mechanical strength, and unstable interfacial contact. They are difficult to balance dendrite suppression and electrolyte interface compatibility, leading to severe zinc dendrite growth, corrosion, and hydrogen evolution reactions, which affect battery safety and cycle life.
A three-dimensional framework was constructed using electrospun polyacrylonitrile nanofibers, and a composite hydrogel protective layer was prepared by in-situ ultraviolet crosslinking. Combining the high porosity of the polymer and the ionic conductivity of the hydrogel, a robust zinc ion transport channel was formed, which enhanced the hydrophilicity of the interface and blocked the contact between water molecules and the zinc anode.
It achieves the suppression of zinc dendrite growth and the reduction of side reactions, improves the cycle stability and deposition uniformity of zinc anode, enhances coulombic efficiency and battery safety, and has good prospects for industrial application.
Smart Images
Figure CN121885508A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of zinc anode technology, and in particular to a zinc anode containing an electrospun composite hydrogel protective layer, its preparation method, and its application. Background Technology
[0002] Aqueous zinc-ion batteries, as a next-generation safe, low-cost, and environmentally friendly energy storage system, show broad application prospects in flexible electronics, large-scale energy storage, and wearable devices. Zinc metal anodes possess significant advantages such as high theoretical capacity (820 mAh g⁻¹, 5855 mAh cm⁻³), low redox potential (-0.76 V vs. SHE), abundant reserves, and low cost. Furthermore, the use of aqueous electrolytes fundamentally avoids the flammability and explosiveness issues associated with organic batteries, making them particularly suitable for wearable and implantable devices with extremely high safety requirements. However, zinc anodes still face a series of serious challenges in practical applications, mainly including: Zinc dendrite growth: During electrochemical deposition, uneven distribution of zinc ions on the electrode surface and excessively high local current density cause zinc to preferentially deposit at protrusions, forming dendrites. Dendrites can not only puncture the diaphragm and cause short circuits, but also detach during cycling, resulting in loss of active material and capacity decay.
[0003] Corrosion and Hydrogen Evolution Reaction: Zinc is thermodynamically unstable in aqueous electrolytes and readily undergoes a corrosion reaction (Zn + 2H₂O → Zn(OH)₂ + H₂↑), accompanied by the release of a large amount of hydrogen gas. This not only consumes active zinc but also causes battery swelling and increased internal pressure, severely affecting battery safety and cycle life.
[0004] Passivation layer formation: Insulating or low-conductivity passivation layers such as ZnO and Zn(OH)2 are easily formed on the zinc surface, which increases the interfacial impedance, hinders zinc ion transport, and leads to increased polarization and decreased capacity.
[0005] The aforementioned problems are interconnected, forming a vicious cycle of "dendration-corrosion-passivation," which severely restricts the practical application of aqueous zinc-ion batteries. Currently, modification strategies for zinc anodes mainly include: Electrolyte optimization: adding corrosion inhibitors, adjusting pH, and using high-concentration electrolytes to suppress side reactions; Structural design: Construct a three-dimensional porous current collector to reduce local current density and guide uniform deposition; Surface modification: An artificial protective layer is constructed on the surface of the zinc anode to physically isolate zinc from the electrolyte and promote uniform ion transport.
[0006] Among them, the surface protective layer strategy has attracted much attention due to its ease of operation and significant effects. Existing technologies disclose the use of electrospinning to construct protective layers, but it suffers from technical problems such as insufficient density of the protective layer, low ionic conductivity, poor mechanical strength, unstable contact with the zinc anode interface, easy detachment or damage during long-term cycling, and difficulty in simultaneously achieving dendrite suppression and electrolyte interface compatibility. Summary of the Invention
[0007] The purpose of this invention is to address the shortcomings of the prior art by proposing a zinc anode with an electrospun composite hydrogel protective layer, its preparation method, and its application. The electrospun composite hydrogel protective layer can effectively inhibit zinc dendrite growth, reduce side reactions, and improve the cycle stability and deposition uniformity of the zinc anode.
[0008] The first objective of this invention is to provide a method for preparing a zinc anode containing an electrospun composite hydrogel protective layer, comprising the following steps: Polyacrylonitrile was dissolved in N,N-dimethylformamide to prepare an electrospinning solution; Polyacrylonitrile nanofiber layers were prepared by electrospinning on zinc foil surface; A hydrogel precursor solution containing 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, a crosslinking agent, and a UV initiator was prepared; the hydrogel precursor solution was coated on the surface of the fiber layer, crosslinked by UV light, and dried to obtain the zinc anode.
[0009] Furthermore, the hydrogel precursor solution contains 1 mol / L of 2-acrylamide-2-methylpropanesulfonic acid and 1 mol / L of acrylamide.
[0010] Furthermore, the crosslinking agent is 0.05 mol% and the UV initiator is 0.1 mol%.
[0011] Furthermore, in the polyacrylonitrile nanofiber layer, the polyacrylonitrile nanofibers have a diameter of 200-500 nm, a porosity of 60%-90%, and a thickness of 10-100 μm.
[0012] Furthermore, the crosslinking agent is N,N'-methylenebisacrylamide.
[0013] Furthermore, the ultraviolet initiator is 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone.
[0014] Furthermore, the electrospinning process parameters are: voltage 12~15 kV, feed speed 0.8~1 mL / h, distance between spinneret and collecting plate 15~18 cm, and spinning time 4 hours.
[0015] Furthermore, the ultraviolet light crosslinking time is 30-60 minutes, the drying temperature after crosslinking is 60-80℃, and the drying time is 8-12 hours.
[0016] The second objective of this invention is to provide a zinc anode containing an electrospun composite hydrogel protective layer prepared by the above-described preparation method.
[0017] A third objective of this invention is to provide a zinc-ion battery comprising the zinc anode with the aforementioned electrospun composite hydrogel protective layer.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. A synergistic effect of "mechanical support" and "ion conduction" is achieved, fundamentally inhibiting dendrite growth. Electrospun polyacrylonitrile (PAN) nanofibers construct a robust, high-porosity three-dimensional framework that can effectively disperse deposition stress and inhibit disordered protrusions of zinc deposits; at the same time, the in-situ composite AMPS-based hydrogel, as an ion conductor, completely fills the pores of the fiber network, providing a uniform and continuous zinc ion transport channel; 2. A stable, hydrophilic solid-liquid interface was constructed, significantly reducing side reactions and improving coulombic efficiency. The hydrogel network is rich in hydrophilic functional groups (such as -SO3). - This significantly improves the wettability of the electrode / electrolyte interface and reduces the local current density. Simultaneously, this composite layer acts as a physical barrier, effectively preventing direct contact between water molecules and the zinc anode, thus inhibiting corrosion and hydrogen evolution reactions. 3. The in-situ integration process endows the protective layer with excellent structural integrity and long-term cycling stability. This invention employs a continuous process of "electrospinning followed by in-situ UV crosslinking," enabling a strong chemical / physical bond between the hydrogel, the fiber skeleton, and the zinc substrate, avoiding the problems of easy peeling and cracking found in traditional coatings. The three-dimensional interpenetrating network structure can adapt to volume changes during zinc deposition / peeling. 4. A simple and scalable preparation method is provided, with promising prospects for industrial application. The entire preparation process is based on mature electrospinning and UV curing technologies, with concise steps and no need for complex equipment or harsh conditions (such as high temperature and high pressure). This method is applicable to various flexible substrates (such as zinc foil), has a wide process window, and is easy to achieve large-area, continuous production, providing a reliable technical path for the large-scale manufacturing of high-performance aqueous zinc-ion batteries. Attached Figure Description
[0019] Figure 1 The image shows a scanning electron microscope image of the Zn@PAN electrode in Comparative Example 1, revealing the three-dimensional porous network structure formed by polyacrylonitrile nanofibers on the zinc foil surface. Figure 2The image shows a scanning electron microscope image of the Zn@PAN-G composite electrode in Example 1, illustrating the continuous and dense composite protective layer formed after the hydrogel completely fills the pores of the PAN fibers. Figure 3a , 3b The curves for Bare Zn and Zn@PAN-G, Zn@PAN, and Zn@G symmetrical cells are shown in Figures 3c and 4c, respectively, under conditions of 2 mA / cm² and 0.5 mAh / cm². Figure 4 The graph shows a long-cycle comparison of the coulombic efficiency of Bare Zn and Zn@PAN-G asymmetric cells assembled with copper foil under conditions of 5 mA / cm² and 1 mAh / cm². Figure 5 Tafel curves and linear sweep voltammetry curves for Bare Zn and Zn@PAN-G; Figure 6 The images show a comparison of the surface deposition morphology of Bare Zn and Zn@PAN-G after 50 cycles at 2 mA / cm² and 1 mAh / cm². Figure 7 Cyclic voltammetry curves of Zn@PAN-G||NVO full cells at a scan rate of 1 mV / s are shown, revealing two pairs of reversible redox peaks; Figure 8 A comparison of the long-cycle performance and coulombic efficiency of Zn@PAN-G||NVO and Zn||NVO full cells at a current density of 5 A / g. Figure 9 A comparison of the rate performance of Zn@PAN-G||NVO and Zn||NVO full cells in the current density range of 0.5–10 A / g; Figure 10 This is a schematic diagram of the preparation of Zn@PAN-G. Detailed Implementation
[0020] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0021] Comparative Example 1: Preparation of Zn@PAN Electrode This embodiment provides a method for preparing a zinc electrode coated with electrospun polyacrylonitrile nanofibers. Preparation steps: Step 1: Mix polyacrylonitrile powder and N,N-dimethylformamide at a weight ratio of 1:9 and stir continuously at 60°C until completely dissolved to obtain electrospinning precursor solution.
[0022] Step 2: Take 4 mL of the above solution and use an HZ-11 electrospinning device with the voltage set to 15 kV, the feed speed set to 1 mL / h, and the distance between the spinneret and the zinc foil collecting plate set to 15 cm for electrospinning.
[0023] Step 3: After spinning for 4 hours, a zinc electrode with a uniform surface coating of polyacrylonitrile nanofibers was obtained and labeled as Zn@PAN.
[0024] Structural characterization: The surface morphology of Zn@PAN was observed using scanning electron microscopy. The fiber diameter was approximately 200-500 nm, and the interwoven fibers formed a three-dimensional porous network structure (see [link to relevant documentation]). Figure 1 ).
[0025] Comparative Example 2: Preparation of Zn@G Electrode Step 1: Prepare the same hydrogel precursor solution as in Example 1. Step 2: Directly coat the hydrogel precursor solution onto the cleaned and polished surface of bare zinc foil. Step 3: Irradiate in a UV curing chamber for 30 minutes to achieve crosslinking. Step 4: Dry at 60°C for 12 hours to obtain the Zn@G electrode.
[0026] Example 1: Preparation of Zn@PAN-G composite electrode This embodiment provides a zinc electrode with a polyacrylonitrile nanofiber composite hydrogel protective layer and its preparation method. Figure 10 As shown, the preparation steps are as follows: Step 1: Prepare Zn@PAN electrodes according to the method of Comparative Example 1.
[0027] Step 2: Prepare the hydrogel precursor solution, the specific composition of which is as follows: 2-Acrylamide-2-methylpropanesulfonic acid: 1 mol / L; Acrylamide: 1 mol / L; N,N'-methylenebisacrylamide: 0.05 mol% (crosslinking agent); 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone: 0.1 mol% (UV initiator).
[0028] Step 3: Coat the Zn@PAN electrode surface with the above hydrogel precursor solution and place it in an ultraviolet curing chamber for 30-60 minutes to achieve in-situ crosslinking.
[0029] Step 4: After cross-linking is completed, dry at 60℃ for 12 hours to obtain Zn@PAN-G composite electrode.
[0030] Structural characterization: SEM images show that the hydrogel completely fills the pores of the PAN fibers, forming a continuous and dense composite protective layer (see [link to SEM image]). Figure 2 This structure combines the mechanical strength of a fibrous skeleton with the ionic conductivity of a hydrogel.
[0031] Electrochemical performance testing (symmetric cell) The Zn@PAN-G electrode prepared in Example 1 was assembled into a symmetrical cell with pure zinc foil. The electrolyte was 2 mol / L ZnSO4, and the separator was a glass fiber membrane.
[0032] Test results: such as Figure 3a , 3b As shown in Figure 3c, under conditions of 2 mA / cm² and 0.5 mAh / cm², the Zn@PAN-G symmetric cell can cycle stably for more than 5000 hours with the overpotential remaining stable below 50 mV; Zn@PAN and Zn@G cycled for 450 h and 780 h, respectively; while the pure zinc symmetric cell experienced voltage oscillations after about 300 hours and eventually short-circuited.
[0033] Zinc deposition coulombic efficiency test The Zn@PAN-G and Bare Zn prepared in Example 1 were assembled with copper foil to form asymmetric batteries with 2 mol / L ZnSO as electrolyte. The coulombic efficiency at 5 mA / cm² and 1 mAh / cm² was tested.
[0034] Test results: such as Figure 4 As shown, Zn@PAN-G maintains an initial efficiency of 98.8% at 5 mA / cm², and its average coulombic efficiency remains above 99% over a long cycle of more than 1600 cycles. In contrast, Bare Zn has an initial efficiency of only 85.3% under the same conditions, a cycle life of only about 400 cycles, and an average coulombic efficiency of only 96.3%.
[0035] Corrosion and deposition behavior studies Tafel curves and linear sweep voltammetry were performed on Bare Zn and Zn@PAN-G.
[0036] Using an electrochemical workstation, Tafel and LSV tests were performed in a three-electrode system in 2M ZnSO4 and 2M NaSO4 solutions at a scan rate of 1 mv / s.
[0037] Test results: See Figure 5 Zn@PAN-G exhibits a low corrosion current density and a high hydrogen evolution overpotential, indicating that it has good corrosion resistance and hydrogen evolution inhibition capabilities.
[0038] Zinc deposition morphology observation After depositing Zn@PAN-G and Bare Zn at 2 mA / cm² and 1 mAh / cm² for 50 cycles, the battery was disassembled to observe the surface morphology.
[0039] Observation results: See Figure 6SEM images show that Bare Zn surface exhibits obvious dendrites and a loose deposition layer; while Zn@PAN-G surface has uniform and dense zinc deposition without obvious dendrites.
[0040] Assembly and performance testing of NVO full batteries Synthesis of NVO cathode materials Step 1: Dissolve 2.184 g V2O5 and 0.48 g NaOH in 250 mL of deionized water and stir at room temperature for 4 hours to obtain a light yellow solution.
[0041] Step 2: Transfer the above solution to a 300 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene and react at 180°C for 24 hours.
[0042] Step 3: After naturally cooling to room temperature, collect the resulting orange-yellow precipitate, wash thoroughly with deionized water, and dry overnight in a vacuum oven at 80℃ to obtain Na2V6O. 16 • 3H2O (NVO) powder.
[0043] 2. Preparation of NVO positive electrode sheet Step 1: Mix NVO powder, Super P conductive carbon black and PVDF binder in a mass ratio of 80:10:10.
[0044] Step 2: Add an appropriate amount of N-methylpyrrolidone solvent and stir for 4 hours to obtain a uniform slurry.
[0045] Step 3: Use a scraper to evenly coat the slurry onto the surface of the titanium foil current collector.
[0046] Step 4: Dry at 80℃ for 12 hours, then punch into electrodes with a diameter of 10 mm. The surface loading of active material is approximately 1.5–2.0 mg / cm².
[0047] Using Zn@PAN-G prepared in Example 1 as the negative electrode and NVO as the positive electrode, a full cell was assembled and electrochemical tests were performed.
[0048] Cyclic Voltmeter-Vertical Voltage (CV) Test Cyclic voltammetry (CV) curves (see) Figure 7 The NVO cathode exhibits two pairs of typical redox peaks, corresponding to the insertion / extraction reactions of zinc ions in the vanadium-based cathode. This indicates that the inherent redox process of the NVO cathode is not affected by the PAN-G protective layer.
[0049] Long-cycle performance testing See Figure 8 After 1000 cycles at a current density of 5 A / g, the Zn@PAN-G||NVO battery still maintains a capacity of 194.8 mAh g. -¹ Its capacity is higher than that of Zn||NVO batteries, which have a capacity of 144.7 mAh g. - ¹, with an average coulombic efficiency >99.3%.
[0050] Ratio Performance Test Figure 9 The rate performance of two full cells was demonstrated in the current density range from 0.5 to 10 A / g. The average specific capacity of the Zn@PAN-G||NVO cell at different current densities was 345.1, 338.7, 324.5, 271.5, and 226.8 mAh / g, respectively, all of which were superior to those of the Zn||NVO cell (339.9, 331, 316, 243.2, and 176.2 mAh / g). For any points not covered above, existing technologies shall apply.
[0051] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a zinc anode containing an electrospun composite hydrogel protective layer, characterized in that, Includes the following steps: Polyacrylonitrile was dissolved in N,N-dimethylformamide to prepare an electrospinning solution; Polyacrylonitrile nanofiber layers were prepared by electrospinning on zinc foil surface; A hydrogel precursor solution containing 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, a crosslinking agent, and a UV initiator was prepared; the hydrogel precursor solution was coated on the surface of the fiber layer, crosslinked by UV light, and dried to obtain the zinc anode.
2. The preparation method according to claim 1, characterized in that, The hydrogel precursor solution contains 1 mol / L of 2-acrylamide-2-methylpropanesulfonic acid and 1 mol / L of acrylamide.
3. The preparation method according to claim 1, characterized in that, Crosslinking agent 0.05 mol%, UV initiator 0.1 mol%.
4. The preparation method according to claim 1, characterized in that, The polyacrylonitrile nanofiber layer has a diameter of 200-500 nm, a porosity of 60%-90%, and a thickness of 10-100 μm.
5. The preparation method according to claim 1, characterized in that, The crosslinking agent is N,N'-methylenebisacrylamide.
6. The preparation method according to claim 1, characterized in that, The ultraviolet initiator is 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone.
7. The preparation method according to claim 1, characterized in that, The electrospinning process parameters are: voltage 12~15kV, feed speed 0.8~1 mL / h, distance between spinneret and collecting plate 15~20 cm, and spinning time 4 hours.
8. The preparation method according to claim 4, characterized in that, The ultraviolet light crosslinking time is 30-60 minutes, the drying temperature after crosslinking is 60-80℃, and the drying time is 8-12 hours.
9. A zinc anode containing an electrospun composite hydrogel protective layer prepared by the preparation method according to any one of claims 1-8.
10. A zinc-ion battery, characterized in that, The zinc anode includes the electrospun composite hydrogel protective layer as described in claim 9.