Polymer composite membrane with dual-channel proton blocking function and application of polymer composite membrane in metal battery

Abstract

The invention belongs to the technical field of macromolecular functional materials and electrochemical energy storage, and particularly relates to a polymer composite membrane with a dual-channel proton blocking function and application of the polymer composite membrane in a metal battery. The polymer composite membrane with the dual-channel proton blocking function is formed by compounding polyvinyl alcohol and zwitter-ion modified polypyrrole, and is an ion selective composite membrane capable of blocking proton transmission through dual channels and realizing efficient selective conduction of Zn < 2 + >. The hydrophilic-hydrophobic composite membrane inhibits proton dual-channel migration, keeps Zn < 2 + > high-efficiency conduction, has asymmetric wettability, has a contact angle facing an electrolyte side of 100-110 degrees and a contact angle facing a metal negative electrode side of 70-80 degrees, guarantees interface water resistance, promotes Zn < 2 + > interface transmission, and overcomes the technical defects of the existing hydrophilic-hydrophobic composite membrane.

Description

Technical Field

[0001] This invention belongs to the field of polymer functional materials and electrochemical energy storage technology, and particularly relates to polymer composite membranes with dual-channel proton blocking function and their application in metal batteries. Background Technology

[0002] Aqueous zinc-ion batteries (AZIBs) are advantageous due to their inherent safety, low cost, and high theoretical capacity (820 mAh g) of the zinc metal anode. -1 Zinc oxide (SHE) exhibits significant advantages, demonstrating immense application potential in large-scale energy storage. However, its practical application, especially at high current densities, is severely constrained by the hydrogen evolution reaction (HER) at the zinc anode interface. The thermodynamic potential of HER (-0.42V vs. SHE) is far more positive than the zinc deposition potential. At high current densities, the strong interfacial electric field easily drives the interfacial potential above the thermodynamic equilibrium threshold of HER. This side reaction not only continuously consumes active water molecules in the electrolyte, leading to battery failure, but also generates insulating byproducts such as Zn4SO4(OH)6·xH2O at the interface, severely deteriorating the local chemical environment of the electrode.

[0003] Interface modification is considered an effective strategy to improve the stability of zinc anodes. Hydrophobic coatings (such as PTFE and PVDF) can effectively block water molecules, thereby inhibiting HER (hydrothermal activity), but they lack zinc ion coordination sites, severely hindering Zn absorption. 2+ Transport mechanisms make it difficult for batteries to operate at high rates. Hydrophilic polymers (such as polyvinyl alcohol, PVA) have a dense semi-crystalline structure that can physically block water molecules from approaching the zinc surface. However, PVA is prone to swelling in the electrolyte environment, which disrupts its dense structure and promotes the formation of a continuous hydrogen bond network. As a result, both transport mechanisms will coexist after swelling.

[0004] Although existing studies have proposed hydrophilic-hydrophobic composite membranes to balance water management and ion transport, their inherent phase-separated structure presents a fundamental trade-off: introducing large hydrophobic water zones to fully disrupt hydrogen bonds inevitably blocks Zn. 2+ Migration path. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a polymer composite membrane with dual-channel proton blocking function and its application in metal batteries. The polymer composite membrane with dual-channel proton blocking function is composed of polyvinyl alcohol (PVA) and zwitterionic modified polypyrrole (DMAPS-PPy). This polymer composite membrane with dual-channel proton blocking function is capable of blocking proton transport through two pathways and realizing Zn 2+ A highly efficient and selectively conductive ion-selective composite membrane that suppresses proton dual-channel migration while preserving Zn 2+It exhibits high conductivity and asymmetric wettability, with a contact angle of 100°~110° on the electrolyte side and 70°~80° on the metal anode side. This ensures both interfacial water resistance and promotes Zn... 2+ The interface transmission overcomes the technical defects of existing hydrophilic-hydrophobic composite membranes.

[0006] Based on the above technical objectives, the present invention adopts the following technical solution: This invention protects a polymer composite membrane with dual-channel proton blocking function. The polymer composite membrane with dual-channel proton blocking function is used to regulate interfacial ion migration behavior, reduce side reactions and improve cycle stability. The polymer composite membrane with dual-channel proton blocking function is made by mixing, film formation and cross-linking polyvinyl alcohol, glutaraldehyde and zwitterionic modified polypyrrole.

[0007] The zwitterionic modified polypyrrole is prepared according to the following steps: polypyrrole is dispersed in water, then mixed with N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine and triethylamine, and a Michael addition reaction is carried out. N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine has both positive and negative charge centers, provided by quaternary ammonium cations and sulfonic acid groups, respectively. The role of triethylamine is to adjust the pH (the triethylamine used in this invention...). The very small amount of amine allows the Michael addition reaction to proceed. During the reaction, the nitrogen atom of polypyrrole is the nucleophilic center, and the double bond group of the zwitterion is the electrophilic center. The nucleophilic center reacts with the electrophilic center, causing N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine to be covalently grafted onto the polypyrrole backbone, resulting in zwitterionic modified polypyrrole. Zwitterionic modified polypyrrole is obtained by covalently grafting betaine-type zwitterionic monomers onto the polypyrrole backbone via the Michael addition reaction. The role of polypyrrole is twofold. Besides being able to graft betaine via Michael addition, it also plays another important role: inhibiting the swelling of PVA. Because PVA itself has a very dense structure, it can inhibit the entry of water, thereby inhibiting vehicle migration. However, PVA swells easily in water. The addition of PPy achieves the effect of inhibiting the swelling of PVA.

[0008] The composite process is as follows: using polyvinyl alcohol and zwitterionic modified polypyrrole as raw materials, and glutaraldehyde as a crosslinking agent, the three are mixed in water to form a film and undergo a crosslinking reaction. During the crosslinking process, the hydroxyl groups in polyvinyl alcohol and the aldehyde groups in glutaraldehyde undergo aldol condensation reaction, while the betaine on the zwitterionic modified polypyrrole forms hydrogen bonds with polyvinyl alcohol. Through intermolecular hydrogen bonding, a polymer composite film with dual-channel proton blocking function is obtained.

[0009] Preferably, the mass ratio of polyvinyl alcohol to zwitterionic modified polypyrrole is 5-10:1. Too much polyvinyl alcohol will result in poor proton blocking effect, while too little will reduce the strength of the polymer composite film with dual-channel proton blocking function. Further, the mass ratio of polyvinyl alcohol to zwitterionic modified polypyrrole is 10:1.

[0010] The mass ratio of glutaraldehyde to polyvinyl alcohol is 2~5:100.

[0011] Preferably, the crosslinking reaction is carried out under the following conditions: heating at 80°C for 2 to 8 hours.

[0012] Preferably, the mass ratio of polypyrrole to N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine is 10~100:1; further, the mass ratio of polypyrrole to N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine is 64:1; too much polypyrrole makes it too hydrophobic and reduces its ionic conductivity, while too little polypyrrole is insufficient to react completely with the zwitterionic modified polypyrrole.

[0013] Preferably, the conditions for the Michael addition reaction are: stirring at 50℃~60℃ for 5h~8h.

[0014] Preferably, polypyrrole is prepared by polymerizing pyrrole in the presence of an oxidant to obtain polypyrrole.

[0015] Preferably, the curing conditions are: evaporation of the solvent at 40℃~60℃.

[0016] Preferably, the thickness of the polymer composite film with dual-channel proton blocking function is 5μm to 10μm. If the polymer composite film with dual-channel proton blocking function is too thick, the polarization voltage will increase during battery operation; if it is too thin, it will not be able to maintain its integrity after long-term cycling.

[0017] Preferably, the polymer composite membrane with dual-channel proton blocking function has an amphiphilic hydrophobic gradient, with an electrolyte-side contact angle of 100°~110° and a metal-side contact angle of 70°~80°, balancing water management and ion conduction.

[0018] Preferably, the polymer composite membrane with dual-channel proton blocking function is an ion-selective composite membrane, and the proton conductivity of the polymer composite membrane with dual-channel proton blocking function is not greater than 0.05 mS·cm. -1 Zn 2+ Its ionic conductivity is not less than 5 mS·cm -1 Zn 2+ Electrical conductivity not less than 6.9 × 10 -3 S cm -1 The proton conductivity is almost zero.

[0019] This invention also protects the application of the aforementioned polymer composite film with dual-channel proton blocking function in the preparation of metal batteries. The polymer composite film with dual-channel proton blocking function is loaded onto the surface of the metal anode of the metal battery to suppress hydrogen evolution reaction and dendrite growth. The polymer composite film with dual-channel proton blocking function is loaded onto at least one surface of the metal anode. The metal battery is made of a metal anode loaded with the polymer composite film with dual-channel proton blocking function, a positive electrode, a separator between the positive and negative electrodes, and an aqueous electrolyte.

[0020] Preferably, when the positive electrode of the metal battery is an iodine-based positive electrode, the polymer composite film with dual-channel proton blocking function has a loading of 6 mg cm on one side of the metal negative electrode. -2 ~50mg cm -2 .

[0021] Preferably, the metal battery is selected from aqueous zinc-ion batteries, zinc-iodine batteries, or other multivalent ion batteries, such as Mg... 2+ Battery, Al 3+ Battery.

[0022] Compared with the prior art, the present invention has the following significant advantages: 1. The polymer composite membrane with dual-channel proton blocking function provided by the present invention has a dual-path proton blocking mechanism. Dual-path proton blocking is to suppress two modes of proton migration. Protons have two modes of migration in solution or polymer membrane. One is to combine with water to form hydrated protons, which can migrate directly under the action of an electric field without the need for anything else. This mode of migration is called vehicle migration. The other is to perform hopping transport through a continuous hydrogen bond network. This mode of migration is called Grothuss migration. The dual-channel proton blocking mechanism is as follows: The polymer composite membrane with dual-channel proton blocking function is composed of polyvinyl alcohol (PVA) and zwitterionic modified polypyrrole (DMAPS-PPy). The zwitterions on betaine can form hydrogen bonds with PVA, resulting in a certain cross-linking effect, which inhibits the swelling of polyvinyl alcohol (the mechanism of inhibiting swelling can be explained in two aspects: on the one hand, polypyrrole is hydrophobic, which plays a role in physically blocking water from entering the membrane, while restricting the mobility of PVA molecular chain segments; on the other hand, betaine can form strong hydrogen bonds with the hydroxyl groups of PVA, destroying its original hydrogen bond network, and reducing the macroscopic degree of cross-linking. In short, it changes the cross-linking density of the material, thereby inhibiting the swelling of PVA). This blocks the transport of free water and hydrated protons (Vehicle mechanism), while destroying the long-range hydrogen bond network of PVA, fundamentally inhibiting proton jumping (Grotthuss mechanism), thus achieving a dual and efficient blockade of proton transport.

[0023] The polymer composite membrane with dual-channel proton blocking function provided by this invention has ultra-high ion selectivity: In the polymer composite membrane with dual-channel proton blocking function of this invention, the composite zwitterionic modified polypyrrole contains sulfonic acid groups and quaternary ammonium groups, and the sulfonic acid groups (-SO3) - ) as Zn 2+ Affinity sites, enriched Zn 2+ And promotes its desolvation, forming a low-resistance transport channel; quaternary ammonium groups (N + Electrostatic repulsion of protons allows the polymer composite film with dual-channel proton blocking function to maintain high Zn content. 2+ Electrical conductivity (6.9×10) -3 S cm -1 At the same time, its proton conductivity is more than 100 times lower than that of Nafion membranes, achieving extremely high ion selectivity.

[0024] 2. The polymer composite membrane with dual-channel proton blocking function provided by the invention can also synergistically improve battery performance: When the polymer composite membrane with dual-channel proton blocking function is applied to a zinc-iodine full battery made with an iodine-based cathode, it can effectively suppress the hydrogen evolution reaction and dendrite growth of the zinc anode, and significantly block the shuttle effect of polyiodide ions on the iodine cathode side (betaine has quaternary ammonium positive charge centers, which can form strong ionic bonds with polyiodide ions, and after polyiodide ions combine with quaternary ammonium groups, they will inhibit more quaternary ammonium ions from passing through, thereby inhibiting the shuttle effect of polyiodide ions), enabling the zinc-iodine full battery to operate at high current densities (10 mA cm⁻¹). -2 High surface capacity (10mAh cm⁻¹) -2 ) and ultra-high positive electrode loading (49.3 mg cm⁻¹) -2 Under these conditions, they all exhibited extremely long cycle life and very high capacity retention (e.g., full cells at 6 mg / cm³). -2 After 22,000 cycles under load, the capacity retention rate is 84.8%, which shows broad application prospects in high-speed aqueous zinc-ion batteries.

[0025] 3. Structural Design and Mechanical Properties: The polymer composite membrane with dual-channel proton blocking function of this invention has an amphiphilic hydrophobic gradient. The contact angle of the electrolyte side of the polymer composite membrane with dual-channel proton blocking function is 100°~110°, and the contact angle of the metal side is 70°~80°. The asymmetric wettability design ensures interfacial water resistance and promotes Zn... 2+Interface transport. At the same time, dynamic electrostatic interaction (formed by positive and negative charge centers in betaine, with negative charge centers preferentially binding with zinc ions, neutralizing the electric field formed by the charge, and regenerating the electric field after the zinc ions migrate away) endows the polymer composite film with dual-channel proton blocking function with excellent mechanical properties (tensile strength > 8 MPa, elongation at break > 300%), enabling it to adapt to volume changes during cycling. Attached Figure Description

[0026] Figure 1 The infrared spectra of zwitterionic modified polypyrrole (DMAPS / PPy) and polypyrrole (PPy) in Example 1 are shown.

[0027] Figure 2 The infrared spectra are of the polypyrrole membrane (PVA) of Comparative Example 1 and the polymer composite membrane (hPDMP) with dual-channel proton blocking function of Example 1.

[0028] Figure 3 XPS spectra of zwitterionic modified polypyrrole and polypyrrole; where (a) is the carbon spectrum, (b) is the nitrogen spectrum, and (c) is the oxygen spectrum.

[0029] Figure 4 The interface sem and element distribution diagram of hPDMP@Zn in Example 1 are shown.

[0030] Figure 5 The image shows the contact angle of the polymer composite membrane with dual-channel proton blocking function in Example 1, where the upper image represents the metal side and the lower image represents the electrolyte side.

[0031] Figure 6 Electrochemical impedance spectroscopy (EIS) diagrams are shown for a zinc symmetric battery (hPDMP@Zn) and a bare zinc battery (Bare Zn) prepared using a polymer composite membrane with dual-channel proton blocking function as described in Example 1.

[0032] Figure 7 The graphs show the electrochemical performance of the zinc-copper battery (hPDMP@Zn) and the zinc-copper asymmetric battery (Bare Zn) prepared using the polymer composite membrane with dual-channel proton blocking function in Example 1.

[0033] Figure 8 The graph shows the rate performance of the zinc symmetric battery (hPDMP@Zn) and the bare zinc battery (Bare Zn) prepared using the polymer composite film with dual-channel proton blocking function in Example 1 at different current densities.

[0034] Figure 9 The graph shows the cycle performance of the zinc-iodine full cell assembled using the hPDMP@Zn prepared in Example 1. Detailed Implementation

[0035] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention. Unless otherwise specified, the experimental methods and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.

[0036] Considering that existing hydrophilic-hydrophobic composite membranes introduce large hydrophobic water areas to fully disrupt hydrogen bonds, they also lead to Zn blockage. 2+ To address the technical deficiencies in migration pathways, this invention provides a polymer composite membrane with dual-channel proton blocking functionality. This membrane is composed of polyvinyl alcohol (PVA) and zwitterionic modified polypyrrole (DMAPS-PPy). The zwitterionic modified polypyrrole is prepared from polypyrrole and N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine. N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine provides sulfonic acid groups and quaternary ammonium groups, and the zinc ion affinity sites promote Zn... 2+ The transport and desolvation process, along with the electrostatic repulsion of protons by quaternary ammonium groups, achieves extremely high ion selectivity. Simultaneously, the physical cross-linking mediated by zwitterions inhibits polyvinyl alcohol swelling, blocks the free water transport pathway, and disrupts the long-range hydrogen bond network to suppress proton hopping transport, thereby achieving dual-pathway proton transport blocking.

[0037] The technical solution of the present invention will be studied below using examples and comparative examples. The specific research methods and results are shown below: Example 1 A method for preparing a polymer composite membrane (hPDMP) with dual-channel proton blocking function includes the following steps: S1. Preparation of zwitterionic modified polypyrrole (DMAPS / PPy): Weigh 1.8256 g of ammonium persulfate (APS) and dissolve it in 40 mL of deionized water to obtain an APS solution; separately take 0.552 mL of pyrrole and vortex mix it with 40 mL of deionized water for 5 min to obtain a pyrrole solution. Slowly add the pyrrole solution to the APS solution and react with magnetic stirring at 400 rpm for 5 min at room temperature. Collect the product PPy by filtration and wash it three times with deionized water. The purified PPy was ultrasonically dispersed in 30 mL of deionized water. 8.38 mg of N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine (DMAPS) and 100 μL of triethylamine were added to the dispersion. The mass ratio of polypyrrole to N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine was 64:1. The mixture was stirred at 55°C for 6 h. After the reaction was completed, DMAPS / PPy was obtained by centrifugation and washing.

[0038] S2. Preparation of polymer composite membrane with dual-channel proton blocking function: PVA aqueous solution (5 mL, 10 wt%), glutaraldehyde aqueous solution (125 μL, 50 wt%) and DMAPS / PPy aqueous dispersion (5 mL, 10 g / L) were mixed to obtain a mixture; wherein the mass ratio of polyvinyl alcohol to zwitterionic modified polypyrrole was 7.42:1, and the mass ratio of glutaraldehyde to polyvinyl alcohol was 3:100. The mixture was sonicated for 10 min, then centrifuged at 3000 RPM for 5 min to remove air bubbles, and then coated onto zinc foil. The mixture was heated at 80℃ for 4 h to form a film, thus obtaining a polymer composite membrane with dual-channel proton blocking function.

[0039] The mixture was coated onto an 80 μm thick zinc foil surface, with the thickness controlled. After curing, a polymer composite film (hPDMP film) with dual-channel proton blocking function (i.e., ion-selective composite film) was formed on the zinc foil, resulting in a protected zinc anode, denoted as hPDMP@Zn. Measurements showed that the thickness of the polymer composite film with dual-channel proton blocking function was 7 μm.

[0040] Example 2 A method for preparing a polymer composite membrane (hPDMP) with dual-channel proton blocking function includes the following steps: S1. Preparation of zwitterionic modified polypyrrole (DMAPS / PPy): Weigh 1.8256 g of ammonium persulfate (APS) and dissolve it in 40 mL of deionized water to obtain an APS solution; separately, take 0.552 mL of pyrrole and vortex mix it with 40 mL of deionized water for 5 min to obtain a pyrrole solution. Slowly add the pyrrole solution to the APS solution and react with magnetic stirring at 400 rpm for 5 min at room temperature. Collect the product PPy by filtration and wash it three times with deionized water. Disperse the purified PPy in 30 mL of deionized water by ultrasonication. Add 8.38 mg of N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine (DMAPS) and 100 μL of triethylamine to the dispersion and stir the mixture at 55°C for 6 h. After the reaction is complete, obtain DMAPS / PPy by centrifugation and washing.

[0041] S2. Preparation of polymer composite membrane with dual-channel proton blocking function: PVA aqueous solution (5 mL, 10 wt%), glutaraldehyde aqueous solution (125 μL, 50 wt%) and DMAPS / PPy aqueous dispersion (5 mL, 10 g / L) were mixed to obtain a mixture; wherein, the mass ratio of polyvinyl alcohol to zwitterionic modified polypyrrole was 5:1, and the mass ratio of glutaraldehyde to polyvinyl alcohol was 2:100. The mixture was sonicated for 10 min, then centrifuged at 3000 RPM for 5 min to remove air bubbles, and then coated onto zinc foil. The mixture was heated at 80℃ for 2 h to form a film, thus obtaining a polymer composite membrane with dual-channel proton blocking function.

[0042] The mixture was coated onto an 80 μm thick zinc foil surface, with the thickness controlled. After curing, a polymer composite film (hPDMP film) with dual-channel proton blocking function (i.e., ion-selective composite film) was formed on the zinc foil, resulting in a protected zinc anode, denoted as hPDMP@Zn. Measurements showed that the thickness of the polymer composite film with dual-channel proton blocking function was 5 μm.

[0043] Example 3 A method for preparing a polymer composite membrane (hPDMP) with dual-channel proton blocking function includes the following steps: S1. Preparation of zwitterionic modified polypyrrole (DMAPS / PPy): Weigh 1.8256 g of ammonium persulfate (APS) and dissolve it in 40 mL of deionized water to obtain an APS solution; separately, take 0.552 mL of pyrrole and vortex mix it with 40 mL of deionized water for 5 min to obtain a pyrrole solution. Slowly add the pyrrole solution to the APS solution and react with magnetic stirring at 400 rpm for 5 min at room temperature. Collect the product PPy by filtration and wash it three times with deionized water. Disperse the purified PPy in 30 mL of deionized water by ultrasonication. Add 8.38 mg of N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine (DMAPS) and 100 μL of triethylamine to the dispersion and stir the mixture at 55°C for 6 h. After the reaction is complete, obtain DMAPS / PPy by centrifugation and washing.

[0044] S2. Preparation of polymer composite membrane with dual-channel proton blocking function: PVA aqueous solution (5 mL, 10 wt%), glutaraldehyde aqueous solution (125 μL, 50 wt%) and DMAPS / PPy aqueous dispersion (5 mL, 10 g / L) were mixed to obtain a mixture; wherein, the mass ratio of polyvinyl alcohol to zwitterionic modified polypyrrole was 10:1, and the mass ratio of glutaraldehyde to polyvinyl alcohol was 5:100. The mixture was sonicated for 10 min, then centrifuged at 3000 RPM for 5 min to remove air bubbles, and then coated onto zinc foil. The mixture was heated at 80℃ for 8 h to form a film, thus obtaining a polymer composite membrane with dual-channel proton blocking function.

[0045] The mixture was coated onto an 80 μm thick zinc foil surface, with the thickness controlled. After curing, a polymer composite film (hPDMP film) with dual-channel proton blocking function (i.e., ion-selective composite film) was formed on the zinc foil, resulting in a protected zinc anode, denoted as hPDMP@Zn. Measurements showed that the thickness of the polymer composite film with dual-channel proton blocking function was 10 μm.

[0046] Comparative Example 1 The preparation method of the zinc anode protected by pure PVA film is the same as that in Example 1, except that DMAPS / PPy aqueous dispersion is not added, and includes the following steps: After mixing PVA aqueous solution (5 mL, 10 wt%) and glutaraldehyde aqueous solution (125 μL, 50 wt%), the mixture was sonicated for 10 min and then centrifuged at 3000 RPM for 5 min to remove air bubbles, resulting in a uniform coating slurry.

[0047] The coating slurry was applied to the surface of an 80μm thick zinc foil, with the thickness controlled. After curing, a PVA film was formed on the zinc foil, resulting in a protected zinc anode, denoted as PVA@Zn. The thickness of the PVA film was measured to be 7μm.

[0048] Examples 1 to 3 of this invention all yielded polymer composite films with dual-channel proton blocking function that exhibit excellent ability to regulate interfacial ion migration behavior. The zinc anode hPDMP@Zn from Example 1 is used as an example for further research. Specific research methods and results are shown below: Figure 1 The infrared spectra of polypyrrole and zwitterionic modified polypyrrole are shown. Fourier transform infrared spectroscopy shows that at 1100 cm⁻¹... -1 There is a distinct absorption peak at 1045 cm⁻¹, corresponding to the stretching vibration of S=O; -1 The absorption peak at that point is attributed to -SO3. - The symmetric stretching vibrations of the functional group, these characteristic peaks confirm the successful introduction of the sulfonic acid functional group. Furthermore, at 1566 cm⁻¹... -1 and 1200cm -1 Vibrational peaks related to C–N bonds were observed at the site, providing further evidence for the covalent cross-linking between DMAPS and the PPy backbone.

[0049] Figure 2 Infrared spectra of the PVA film of Comparative Example 1 and the polymer composite film with dual-channel proton blocking function of Example 1: Fourier transform infrared analysis further confirmed these molecular interactions. Besides S=O (1100cm⁻¹), -1 ) and –SO3⁻ symmetric stretching vibration (1045cm) -1 In addition to the characteristic peak of ), 1566 cm⁻¹ -1 and 1200cm -1 The C–N vibrational peak at 1650 cm⁻¹ confirms the covalent connection between DMAPS and the PPy skeleton; furthermore, the peak at 1650 cm⁻¹... -1 A broad absorption peak appears nearby, which can be attributed to –SO3. - The hydrogen bonding between the hydrated sulfonic acid domain and the hydrogen bond network indicates the formation of the hydrated sulfonic acid domain and the reorganization of the hydrogen bond network.

[0050] Figure 3 XPS images of polypyrrole and zwitterionic modified polypyrrole are shown. X-ray photoelectron spectroscopy analysis of carbon spectra confirmed the chemical state evolution at the interface. The CN bond binding energy shifted positively from 285.4 eV to 285.6 eV (Δ=0.2 eV). This change provides direct evidence for the formation of covalent bonds between DMAPS and PPy.

[0051] X-ray photoelectron spectroscopy analysis of the nitrogen spectrum confirmed that, except for the pyrrole / neutral polypyrrole component (~399.6 eV), a significant quaternary ammonium nitrogen (N) component appeared at ~402.2 eV. + The characteristic peak is absent in the original polypyrrole and is consistent with the characteristics of the zwitterionic DMAPS molecular fragment.

[0052] X-ray photoelectron spectroscopy analysis of the oxygen spectrum confirmed that the DMAPS sulfonic acid group exhibited two oxidative environments, forming two peaks at ~531 eV (O=S) and ~532.6 eV (O–S), with an area ratio of approximately 1:2, consistent with the resonance structure of –SO3⁻. In contrast, the residual inorganic sulfate typically exhibited a single and narrow O 1s peak at ~532.2 eV, without the 1:2 splitting characteristic.

[0053] Figure 4 The image shows cross-sectional scanning electron microscopy (SEM) images and corresponding elemental distribution maps of hPDMP@Zn. The hPDMP coating exhibits a dense and uniform morphology (approximately 7 μm thick), tightly bonded to the zinc substrate, with no observed porosity or delamination. The carbon elemental distribution map is clear, showing a continuous distribution of the polypyrrole framework, while the uniform zinc signal beneath the hPDMP coating confirms that the hPDMP coating effectively blocks electrolyte penetration and prevents interfacial corrosion.

[0054] Figure 5 The image shows the contact angle of the polymer composite membrane with dual-channel proton blocking function. The top side is the metal side, and the bottom side is the electrolyte side. Water contact angle tests were performed on both sides of the hPDMP membrane. As shown in the figure, the electrolyte side exhibits a high contact angle of 104.2°, indicating its enhanced hydrophobicity, which can effectively block water molecules and inhibit hydrogen evolution reaction at the zinc interface. The zinc side has a contact angle of 74.7°, showing moderate hydrophilicity that is beneficial to the transport of zinc ions within the membrane.

[0055] Symmetric cell test: Zn||Zn symmetric cells were assembled using zinc anodes prepared in Example 1 and Comparative Example 1, respectively. Figure 6 The impedance diagram shows that the hPDMP-modified zinc battery has a significantly lower impedance than the bare zinc symmetric battery, which allows the battery to have a smaller overpotential during operation, reducing energy consumption and also reducing the efficiency of the hydrogen evolution side reaction.

[0056] Zinc-copper asymmetric battery test: Zn||Cu asymmetric batteries were assembled using zinc anodes prepared in Example 1 and Comparative Example 1, respectively. Figure 7 The results show that the ion-selective hPDMP coating significantly improves the cycle reversibility and interfacial stability of the zinc metal anode at 5 mA cm⁻¹. -2 Current density and 0.25 mAh cm⁻¹ -2 Under the deposition capacity conditions, coulombic efficiency tests on Zn||hPDMP@Cu and Zn||Cu asymmetric cells showed that hPDMP@Cu maintained an average coulombic efficiency of 99.68% throughout 7500 cycles, while bare copper cells exhibited rapid degradation, with their coulombic efficiency dropping below 90% after 700 cycles.

[0057] The rate performance of the symmetrical battery was evaluated at different current densities. Figure 8 The results show that hPDMP@Zn even at 20 mA cm -2 Even at high current densities, it still exhibits a stable voltage curve and a low overpotential (ΔV≈160mV), while the bare zinc electrode shows significant polarization (>350mV).

[0058] Figure 9 The results showed that, in full-cell testing, using hPDMP@Zn prepared in Example 1 as the negative electrode, and with a high loading (6 mg / cm³), the following conditions were met: -2 and 49.3mg cm -2 Using an iodine / carbon composite electrode as the positive electrode, a zinc-iodine full cell was assembled. At 1 A g -1 At a current density of 6 mg cm -2 The full-cell load retained 84.8% capacity and 49.3 mg / cm³ after 22,000 cycles. -2 Even a full battery with ultra-high load can stably cycle more than 500 times.

[0059] The polymer composite membrane with dual-channel proton blocking function provided by this invention utilizes a unique dual-channel proton blocking mechanism and highly efficient Zn 2+ Selective transport capability significantly improves the cycle life and practicality of aqueous zinc metal batteries (especially high-area-capacity zinc-iodine batteries), and has broad prospects for commercial application.

[0060] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations of this invention that fall within the scope of the claims and their equivalents.

Claims

1. A polymer composite membrane having a dual-channel proton blocking function, characterized by, The polymer composite membrane with dual-channel proton blocking function is made by mixing, forming, and cross-linking polyvinyl alcohol, glutaraldehyde, and zwitterionic modified polypyrrole. The zwitterionic modified polypyrrole was prepared according to the following steps: polypyrrole and N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine were used as raw materials, and triethylamine was used as a pH adjuster. The three were mixed in water and a Michael addition reaction was carried out. During the reaction, N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine was covalently grafted onto the polypyrrole backbone to obtain zwitterionic modified polypyrrole. The composite process is as follows: using polyvinyl alcohol and zwitterionic modified polypyrrole as raw materials, and glutaraldehyde as a crosslinking agent, the three are mixed in water to form a film and undergo a crosslinking reaction. During the crosslinking process, the hydroxyl groups in polyvinyl alcohol and the aldehyde groups in glutaraldehyde undergo aldol condensation reaction, while the betaine on the zwitterionic modified polypyrrole forms hydrogen bonds with polyvinyl alcohol, resulting in a polymer composite film with dual-channel proton blocking function.

2. The polymer composite membrane having a dual-channel proton blocking function according to claim 1, characterized by, The mass ratio of polyvinyl alcohol to zwitterionic modified polypyrrole is 5~10:1, and the mass ratio of glutaraldehyde to polyvinyl alcohol is 2~5:

100.

3. The polymer composite membrane having a dual-channel proton blocking function according to claim 1, characterized in that, The conditions for the cross-linking reaction are: heating at 80℃ for 2 to 8 hours.

4. The polymer composite membrane having a dual-channel proton blocking function according to claim 1, characterized in that, The mass ratio of polypyrrole to N,N-dimethyl-N-(2-methacryloyloxyethyl)-N-(3-sulfopropyl)ammonium betaine is 10~100:

1.

5. The polymer composite membrane with dual-channel proton blocking function according to claim 1, characterized in that, The conditions for the Michael addition reaction are: stirring at 50℃~60℃ for 5h~8h.

6. The polymer composite membrane having a dual-channel proton blocking function according to claim 1, wherein The thickness of the polymer composite membrane with dual-channel proton blocking function is 5μm~10μm.

7. The polymer composite membrane having a dual-channel proton blocking function according to claim 1, wherein The polymer composite membrane with dual-channel proton blocking function has an amphiphilic hydrophobic gradient. The contact angle of the electrolyte side of the polymer composite membrane with dual-channel proton blocking function is 100°~110°, and the contact angle of the metal side is 70°~80°.

8. The polymer composite membrane having a dual-channel proton blocking function according to claim 1, wherein, Polymer composite membranes with dual-channel proton blocking function are ion-selective composite membranes, and the proton conductivity of polymer composite membranes with dual-channel proton blocking function is no greater than 0.05 mS·cm. -1 Zn 2+ Its ionic conductivity is not less than 5 mS·cm -1 .

9. The application of the polymer composite membrane with dual-channel proton blocking function as described in claim 1 in the preparation of metal batteries.

10. Use according to claim 9, characterized in that, A polymer composite membrane with dual-channel proton blocking function is loaded onto the surface of the metal anode of a metal battery.

Images