Functional diaphragm for inhibiting growth of zinc anode dendrites, preparation method and application

Abstract

The invention discloses a functional diaphragm for inhibiting growth of zinc anode dendrites, a preparation method and application, and belongs to the field of aqueous zinc ion batteries, the preparation method comprises the following steps: preparing an imine-connected DBSA-COF material through a normal temperature interface synthesis method; the preparation method comprises the following steps: dissolving PEEK in concentrated sulfuric acid, reacting to obtain a first mixed solution, pouring the first mixed solution into water at 0 DEG C to obtain a white precipitate, and performing vacuum drying to obtain SPEEK; dissolving SPEEK in an organic solvent to prepare a second mixed solution; and adding a DBSA-COF material into the second mixed solution to prepare a third mixed solution, and dropwise adding the third mixed solution onto a glass plate through a solution casting method to prepare the functional diaphragm. The preparation method disclosed by the invention is simple in process, convenient to operate, easy to realize large-scale production and relatively high in application value.

Description

Technical Field

[0001] The present invention relates to the field of aqueous zinc ion batteries, and in particular to a functional diaphragm for inhibiting zinc anode dendrite growth, a preparation method and applications thereof. Background Art

[0002] Aqueous zinc-ion batteries (AZIBs) are attractive due to their high safety, low cost, environmental friendliness, and high theoretical capacity of zinc (820 mAh g -1 ) and other advantages, it is considered a highly promising energy storage technology with the potential for widespread application in large-scale energy storage. However, problems such as dendrite growth, corrosion, and hydrogen evolution during the charge and discharge processes of the zinc anode severely limit its cycling stability and Coulombic efficiency, hindering the commercialization of AZIBs. Research has shown that a uniform zinc ion flow can be guided by a separator, achieving uniform zinc deposition.

[0003] Currently, the separators widely used in AZIBs primarily include glass fiber (GF) separators, polyolefin separators (such as polyethylene and polypropylene), and cellulose-based separators. In addition to cost, GF separators are also characterized by large thickness and uneven pore size, which hinder the uniform transport of zinc ions. Polyolefin separators have good mechanical strength and chemical stability, but their poor hydrophilicity leads to insufficient electrolyte wettability, making it impossible to effectively regulate ion transport pathways and, consequently, inhibit zinc dendrite growth. While cellulose-based separators have good hydrophilicity, they have low mechanical strength, are prone to deformation during long-term charge and discharge cycles, and have limited effectiveness in inhibiting zinc dendrites. These separator shortcomings make the zinc anode susceptible to uncontrolled dendritic growth during charge and discharge, which can then pierce the separator, causing internal short circuits in the battery. This in turn exacerbates zinc corrosion and hydrogen evolution reactions, severely impacting the battery's cycle life and coulombic efficiency. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth, so as to solve the problem that the GF diaphragm in the prior art has a large thickness and uneven pore size distribution, resulting in uneven Zn 2+ The ion flow exacerbates the uneven zinc deposition and thus cannot suppress the growth of zinc dendrites.

[0005] The present invention is achieved through the following technical solution. A method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth comprises the following steps: S100, preparing an imine-linked DBSA-COF material by a room-temperature interfacial synthesis method; S200, dissolving PEEK in concentrated sulfuric acid, reacting for 5 to 7 hours to prepare a first mixed solution, pouring the first mixed solution into 0°C water to obtain a white precipitate, repeatedly washing the white precipitate until the pH is 6 to 7, and preparing SPEEK by vacuum drying; S300, dissolving the SPEEK in an organic solvent to prepare a second mixed solution with a mass fraction of 5% to 8%; S400, adding the DBSA-COF material to the second mixed solution, fully mixing and uniformly dispersing it to prepare a third mixed solution, dropping the third mixed solution onto a glass plate by a solution casting method, and vacuum drying to prepare a functional diaphragm.

[0006] Furthermore, the temperature of the concentrated sulfuric acid in which PEEK is dissolved is 50-55°C.

[0007] Furthermore, the degree of sulfonation of SPEEK is 50% to 80%.

[0008] Furthermore, the sulfonation degree of SPEEK is preferably 60% to 70%.

[0009] Furthermore, the organic solvent is a combination of one or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0010] Furthermore, the mass ratio of SPEEK to DBSA-COF in the third mixed solution is 99.5:0.5~97:3.

[0011] Furthermore, the mass ratio of SPEEK to DBSA-COF in the third mixed solution is preferably 99:1 to 98:2.

[0012] Furthermore, the vacuum drying temperature of the functional diaphragm is 60°C~120°C, and the drying time is 6~24 h.

[0013] Furthermore, the DBSA-COF material is prepared by condensing benzenesulfonamide monomers with aldehyde monomers under room temperature interfacial conditions to form an imine-linked covalent organic framework material, including the following sub-steps: S110, dissolving 0.3 M 2,4,6-triformylphloroglucinol in 100 mL of o-dichlorobenzene to prepare an organic phase solution; S120, dissolving 0.45 M 2,5-diaminobenzenesulfonic acid in H2O to prepare an aqueous phase solution; S130, slowly adding the aqueous phase solution to the organic phase solution, and adding 6 mM acetic acid to the aqueous phase solution as a catalyst; S140, then preparing DBSA-COF by room temperature interfacial synthesis, and alternately washing DBSA-COF in N,N-dimethylformamide and ethanol solvents, and freeze-drying to obtain DBSA-COF.

[0014] Another aspect of the present invention provides a functional diaphragm for inhibiting zinc anode dendrite growth, wherein the functional diaphragm is prepared according to the preparation method described above.

[0015] Furthermore, the thickness of the functional membrane is 10-100 µm.

[0016] Furthermore, the functional membrane preferably has a thickness of 50 μm.

[0017] Furthermore, the functional membrane has a microphase separation structure, in which a microphase separation region is formed between the hydrophilic -SO3H in SPEEK and the hydrophobic main chain. 2+ ions provide a uniform transmission channel; at the same time, DBSA-COF and -SO3H in SPEEK further promote microphase separation through electrostatic repulsion, and the -NH group in DBSA-COF is Zn 2+ Ions provide abundant transport sites.

[0018] The present invention also provides an application of a functional diaphragm for inhibiting zinc anode dendrite growth. The functional diaphragm prepared according to the method as described above has the following applications: (1) application in the preparation of zinc ion batteries; (2) application in improving the cycle stability of zinc ion batteries; (3) application in improving the safety of zinc ion batteries; (4) application in inhibiting zinc anode dendrite growth; and (5) application in inhibiting zinc anode dendrite side reactions.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] 1. The abundant -SO3H groups, -NH and C=O in the SPEEK / DBSA-COF functional membrane of the present invention serve as electron-rich groups to Zn 2+ The ions have strong adsorption capacity and can quickly anchor Zn 2+ ions and transport them, achieving fast ion transport kinetics.

[0021] 2. Microphase separation in the SPEEK / DBSA-COF functional membrane of the present invention imparts Zn 2+ More ion transmission channels effectively regulate the Zn near the zinc anode 2+ Ion flow, Zn 2+ The ions are uniformly deposited on the anode surface, thus realizing a zinc anode without zinc dendrite growth and significantly improving the cycling stability of AZIBs.

[0022] 3. The interaction between the functional groups in the functional membrane of the present invention and the zinc ions can reduce the polarization of the zinc anode, reduce the occurrence of corrosion and hydrogen evolution reaction, and further improve the coulombic efficiency and service life of the battery.

[0023] 4. The functional diaphragm of the present invention has excellent mechanical properties. PEEK, as an engineering plastic, gives SPEEK excellent mechanical strength. The hydrogen bond network formed between -NH and -SO3H of DBSA-COF further enhances its mechanical strength, preventing the growing dendrites from piercing the diaphragm and causing battery short circuit during the charge / discharge process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0025] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of SPEEK provided in Example 2 of the present invention.

[0026] Figure 2 This is the XRD spectrum of the DBSA-COF material provided in Example 2 of the present invention.

[0027] Figure 3 This is a nucleation overpotential diagram of the Zn|Cu battery provided in Example 2 of the present invention.

[0028] Figure 4 This is a constant current charge and discharge curve diagram of the Zn|Zn battery provided in Example 2 of the present invention.

[0029] Figure 5 This is a constant current charge and discharge curve diagram of the Zn|Zn symmetrical battery provided in Example 2 of the present invention at different current densities.

[0030] Figure 6 This is a diagram showing the depth of discharge test of the Zn|Zn symmetrical battery provided in Example 2 of the present invention.

[0031] Figure 7 This is an SEM image of the Zn foil morphology provided in Example 2 of the present invention.

[0032] Figure 8 This is a long cycle stability diagram of the battery provided in Example 2 of the present invention.

[0033] Figure 9 This is a diagram of the coulombic efficiency of the battery provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0035] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All references mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related thereto. In the event of a conflict with any incorporated reference, the present specification controls. As used herein, the terms "including," "comprising," "having," "containing," and the like are open-ended, meaning to include, but not be limited to, the terms "a," "an," and "an" include plural references unless the context clearly indicates otherwise. It should be noted that the terms "first," "second," and the like are used solely for convenience of description and distinction and are not to be construed as indicating or implying relative importance. As used herein, the term "about" refers to a range of ±20% of the value that follows it. In some embodiments, the term "about" refers to a range of ±10% of the value that follows it. In some embodiments, the term "about" refers to a range of ±5% of the value that follows it.

[0036] To address many problems in the prior art, the present invention proposes a method for preparing a SPEEK / DBSA-COF functional diaphragm for inhibiting zinc anode dendrite growth. Sulfonated polyetheretherketone (SPEEK) rich in sulfonic acid groups and a sulfonated covalent organic framework (DBSA-COF) are used as the main materials. SPEEK has good electrolyte wettability and ion conductivity, and the sulfonic acid groups give the polymer excellent zinc affinity. DBSA-COF has a highly ordered porous structure and abundant sulfonic acid groups, which can provide additional ion transport channels and form a microphase separation structure with SPEEK, providing more channels for the transport of zinc ions. In addition, the composite functional diaphragm of the present invention can uniformly distribute the electric field and ion flow near the zinc anode, thereby achieving a uniform zinc anode without zinc dendrite growth, significantly improving the cycle stability and safety of AZIBs.

[0037] Example 1

[0038] This embodiment discloses a method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth, the method comprising the following steps:

[0039] Step 1: Prepare the imine-linked DBSA-COF material by room temperature interfacial synthesis.

[0040] Specifically, the DBSA-COF material is formed by condensing benzenesulfonamide monomers and aldehyde monomers under room temperature interfacial conditions to form an imine-linked covalent organic framework material, which can include the following sub-steps:

[0041] 1) Dissolve 0.3 M 2,4,6-triformylphloroglucinol in 100 mL of o-dichlorobenzene to prepare an organic phase solution.

[0042] 2) Dissolve 0.45 M 2,5-diaminobenzenesulfonic acid in H2O to prepare an aqueous solution.

[0043] 3) The aqueous phase solution was slowly added to the organic phase solution, and 6 mM acetic acid was added to the aqueous phase solution as a catalyst.

[0044] 4) DBSA-COF was then prepared by room temperature interfacial synthesis, and DBSA-COF was alternately washed in N,N-dimethylformamide and ethanol solvents, and freeze-dried to obtain DBSA-COF.

[0045] Step 2: PEEK is dissolved in concentrated sulfuric acid and reacted for 5 to 7 hours to prepare a first mixed solution. The first mixed solution is poured into 0°C water to obtain a white precipitate. The white precipitate is repeatedly washed until the pH is 6 to 7, and SPEEK is prepared by vacuum drying.

[0046] Specifically, PEEK is dissolved in concentrated sulfuric acid at a temperature of 50-55°C.

[0047] The sulfonation degree of the SPEEK finally prepared is 50%~80%.

[0048] Step 3: dissolving the SPEEK in an organic solvent to prepare a second mixed solution with a mass fraction of 5% to 8%.

[0049] Specifically, the organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0050] Step 4: Add the DBSA-COF material to the second mixed solution, mix thoroughly and evenly disperse to prepare a third mixed solution. The third mixed solution is dropwise added onto a glass plate by solution casting and vacuum dried to prepare a functional separator.

[0051] Specifically, the mass ratio of SPEEK to DBSA-COF in the third mixed solution is 99.5:0.5~97:3.

[0052] The vacuum drying temperature of the functional diaphragm is 60 ℃~120 ℃, and the drying time is 6~24 h.

[0053] Example 2

[0054] This embodiment discloses a method for preparing a SPEEK / DBSA-COF functional diaphragm for inhibiting zinc anode dendrite growth, comprising the following steps:

[0055] 1. Preparation of SPEEK: Concentrated sulfuric acid was used to react with polyetheretherketone (PEEK) at 50 o C for sulfonation reaction for 5 h, and slowly pour the orange-yellow solution after the reaction into ice water. SPEEK white product precipitates, and is repeatedly washed with deionized water until the pH value of SPEEK reaches neutral, and then placed in a freeze dryer for freeze drying.

[0056] 2. Synthesis of DBSA-COF: 0.3 M 2,4,6-triformylphloroglucinol was dissolved in 100 mL of o-dichlorobenzene (organic phase), and 0.45 M 2,5-diaminobenzenesulfonic acid was dissolved in H2O (H2O phase). The aqueous solution was slowly added to the organic phase, and 6 mM acetic acid was added to the H2O phase as a catalyst. DBSA-COF was then prepared by room-temperature interfacial synthesis. DBSA-COF was alternately washed in DMF and ethanol solvents and freeze-dried to obtain the product DBSA-COF.

[0057] 3. Preparation of SPEEK / DBSA-COF functional membrane: Dissolve the prepared SPEEK in DMF, fully mix a certain amount of DBSA-COF and SPEEK solution and evenly disperse them, and drop the mixed solution onto a glass plate by solution casting. o The functional membrane was prepared by vacuum drying under C conditions.

[0058] 4. Post-treatment of functional membrane: The prepared SPEEK / DBSA-COF functional membrane was cut into membranes with a diameter of 16 mm using a punching machine and immersed in 2 M ZnSO4 electrolyte for 24 h.

[0059] In this example, a novel SPEEK polymer material was used as the functional membrane for AZIBs. The polymer's dense structure ensures uniform zinc ion flow at the zinc anode / electrolyte interface. By combining SPEEK with the porous material DBSA-COF synthesized at room temperature, a functional membrane with a rich pore size was successfully prepared. The SPEEK / DBSA-COF functional membrane preparation method provided in this example offers simple synthesis, low cost, and high economic benefits.

[0060] The SPEEK / DBSA-COF functional membrane prepared in this embodiment was tested and obtained Figures 1 to 8 ,in,

[0061] Figure 1 The H NMR spectrum of SPEEK from this example shows the degree of sulfonation of SPEEK. Chemical shifts in the 6.0 to 8.0 ppm range correspond to aromatic protons in the backbone, while the resonance peak at 7.5 ppm is attributed to the SO3H group of SPEEK, indicating successful sulfonation of the SPEEK polymer. The degree of sulfonation can be calculated using the peak area and the integration of other peaks in the SPEEK 1H NMR spectrum. A SPEEK material with a sulfonation degree of 68% was ultimately synthesized.

[0062] Figure 2 The XRD spectrum of the DBSA-COF material in this embodiment is shown. It can be seen from the figure that the DBSA-COF material synthesized by the method in this embodiment has an ordered structure when analyzed by X-ray diffraction (XRD). The DBSA-COF powder has an ordered structure at 2θ of 12.1. o and 23.7 o Diffraction peaks are shown at , corresponding to the reflections of the (210) and (001) crystal planes, respectively. The peak intensity and width of the diffraction peaks prove that the crystal form of the COF is mainly (001).

[0063] Figure 3 The nucleation overpotential diagram of the SPEEK-DBSA-COF matched Zn|Cu battery in this embodiment is shown. As can be seen from the figure, at 2 mA cm -2 At a current density of 1.5 Å, Zn has a smaller nucleation overpotential of 46.2 mV. This shows that Zn is more easily deposited and has faster deposition kinetics under the guidance of the functional separator.

[0064] Figure 4 The constant current charge and discharge curve of the Zn|Zn battery matched with SPEEK-DBSA-COF in this embodiment is shown. It can be seen from the figure that at 1 mA cm -2 @1 mAh cm -2The Zn|Zn symmetric cell matched by SPEE / DBSA-COF in this embodiment has a high electroplating / stripping performance at 1 mA cm -2 @1 mAh cm -2 At a current density of 1.5 GHz, the Zn|SPEE / DBSA-COF|Zn battery can cycle stably for 980 h. This demonstrates that the SPEE / DBSA-COF functional separator optimizes the reversible plating / stripping properties of Zn, thereby inhibiting the growth of zinc dendrites.

[0065] Figure 5 The constant current charge and discharge curves of the Zn|Zn symmetric battery matched with SPEE / DBSA-COF in this embodiment at different current densities are shown. As can be seen from the figure, as the current density increases from 0.5 to 5 mA cm -2 , and then restored to 0.5 mA cm -2 It exhibits excellent cycling stability.

[0066] Figure 6 The depth of discharge test graph of the Zn|Zn symmetric cell matched with the SPEE / DBSA-COF in this example is shown. As can be seen from the figure, when the depth of discharge is 20.5%, the corresponding cell can stably cycle for 100 hours. This proves that Zn still exhibits reversible plating / stripping behavior under high utilization conditions, once again verifying that the SPEE / DBSA-COF functional separator can guide uniform Zn deposition, reduce the formation of "dead Zn", and prevent further growth of Zn dendrites.

[0067] Figure 7 The Zn|Zn symmetric battery matched with the SPEE / DBSA-COF functional membrane in this embodiment is shown in FIG. -2 @1 mAh cm -2 SEM image of the deposited Zn foil after 25 cycles at the same current density. It can be observed from the figure that the SPEE / DBSA-COF functional membrane guides the Zn to deposit horizontally along the (002) crystal plane, and the deposited Zn layers are stacked to form a dense layer. Figure 4 The constant current charge-discharge long cycle performance corresponds to that of the SPEE / DBSA-COF functional separator, which further verifies that the SPEE / DBSA-COF functional separator alleviates the formation of zinc dendrites and improves the reversibility of Zn electroplating / stripping.

[0068] Figure 8 The long cycle stability diagram of the Zn|NVO full battery matched with the SPEE / DBSA-COF functional membrane in this embodiment is shown. As can be seen from the figure, at 5A g -1 After 6000 cycles under the same conditions, it still maintains a stable discharge specific capacity and exhibits excellent coulombic efficiency.

[0069] Figure 9 The coulombic efficiency diagram of a Zn|SPEE / DBSA-COF|NVO battery fabricated with the functional separator in this example after 24 hours of rest is shown. The diagram demonstrates a high coulombic efficiency of 98.9%. The SPEE / DBSA-COF functional separator inhibits the shuttling of active materials, preventing self-discharge.

[0070] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth, characterized in that: The preparation method comprises: S100, preparing an imine-linked DBSA-COF material by a room-temperature interfacial synthesis method; S200, dissolving PEEK in concentrated sulfuric acid and reacting for 5 to 7 hours to prepare a first mixed solution, The first mixed solution is poured into 0°C water to obtain a white precipitate, the white precipitate is repeatedly washed until the pH is 6-7, and SPEEK is prepared by vacuum drying; S300, dissolving the SPEEK in an organic solvent to prepare a second mixed solution with a mass fraction of 5% to 8%; S400, adding the DBSA-COF material to the second mixed solution, fully mixing and uniformly dispersing to prepare a third mixed solution, The third mixed solution is dropped onto a glass plate by a solution casting method, and vacuum dried to prepare a functional diaphragm.

2. The method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth according to claim 1, wherein: The temperature of the concentrated sulfuric acid in which PEEK is dissolved is 50-55°C.

3. The method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth according to claim 1, characterized in that The sulfonation degree of the SPEEK is 50% to 80%.

4. The method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth according to claim 1, wherein: The organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

5. The method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth according to claim 1, characterized in that: The mass ratio of SPEEK to DBSA-COF in the third mixed solution is 99.5:0.5~97:

3.

6. The method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth according to claim 1, characterized in that: The vacuum drying temperature of the functional diaphragm is 60° C. to 120° C., and the drying time is 6 to 24 hours.

7. The method for preparing a functional diaphragm for inhibiting zinc anode dendrite growth according to claim 1, characterized in that: The DBSA-COF material is prepared by condensing benzenesulfonamide monomers and aldehyde monomers under room temperature interfacial conditions to form an imine-linked covalent organic framework material, including the following sub-steps: S110, dissolving 0.3 M 2,4,6-triformylphloroglucinol in 100 mL of o-dichlorobenzene to prepare an organic phase solution; S120, dissolving 0.45 M 2,5-diaminobenzenesulfonic acid in H2O to prepare an aqueous solution; S130, slowly adding the aqueous phase solution to the organic phase solution, and adding 6 mM acetic acid to the aqueous phase solution as a catalyst; S140. DBSA-COF is then prepared by a room temperature interfacial synthesis method. The DBSA-COF is alternately washed in N,N-dimethylformamide and ethanol solvents, and freeze-dried to obtain DBSA-COF.

8. A functional diaphragm for inhibiting zinc anode dendrite growth, characterized in that: The functional diaphragm is prepared according to the preparation method according to any one of claims 1 to 7, The thickness of the functional diaphragm is 10-100 μm.

9. The functional diaphragm for inhibiting zinc anode dendrite growth according to claim 8, characterized in that: The functional membrane has a microphase separation structure, The hydrophilic -SO3H in SPEEK forms a microphase separation region with the hydrophobic main chain, which is Zn 2+ Ions provide a uniform transport channel; At the same time, DBSA-COF and -SO3H in SPEEK further promote microphase separation through electrostatic repulsion, and the -NH group in DBSA-COF is Zn 2+ Ions provide abundant transport sites.

10. An application of a functional diaphragm for inhibiting zinc anode dendrite growth, characterized in that: The functional diaphragm prepared according to the preparation method according to any one of claims 1 to 7 includes the following applications: (1) Application in the preparation of zinc ion batteries; (2) Application in improving the cycling stability of zinc-ion batteries; (3) Application in improving the safety of zinc-ion batteries; (4) Application in inhibiting zinc anode dendrite growth; (5) Application in inhibiting zinc anode side reactions.

Images