A method for preparing a three-dimensional graphene-COF interlocking material and its application in zinc-ion batteries

Abstract

This invention belongs to the field of micro / nano structure material design and battery energy storage technology, and relates to a method for preparing a three-dimensional graphene-COF interlocking material: First, by controlling the amination and reduction of graphene oxide, amine functional groups are precisely constructed on its surface, serving as active sites for heterogeneous assembly; then, in solution blending, the enhanced multiple intermolecular forces between the amine groups and the COF precursor drive the COF units to undergo oriented adsorption and two-dimensional ordered pre-assembly on the graphene surface, forming a molecular-level anchor array; subsequently, through a solvothermal reaction, interfacial covalent condensation and π-plane-induced epitaxial growth are synergistically achieved, causing the COF layer to crystallize and form a strongly coupled heterojunction with the deeply reduced and structurally repaired graphene at the molecular level; finally, after freeze-drying and shaping, a dual continuous conductive network carrier with a stable heterointerface, three-dimensional interlocking channels, and an intrinsic built-in electric field is obtained.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano structure material design and battery energy storage technology, and relates to a method for preparing a three-dimensional graphene-COF interlocking material and its application in zinc-ion batteries. Background Technology

[0002] Aqueous zinc-ion batteries demonstrate significant potential and value in the economical, efficient, and sustainable field of energy conversion and storage. Zinc-ion batteries utilize non-flammable aqueous electrolytes to ensure high ionic conductivity and battery safety. Furthermore, zinc metal is abundant and easily recyclable, and the preparation process of aqueous electrolytes is simple; these factors collectively reduce production costs and improve economic feasibility. Zinc metal, as the negative electrode, possesses an ideal redox potential (-0.76 V vs. SHE) and a high-quality specific capacity (820 mAh·g). -1 ) and high volumetric capacity (5855 mAh·cm³) -3 Zinc-ion batteries can be matched with zinc-free cathodes to form high-capacity battery systems, making them a promising candidate for high-energy-density energy storage systems.

[0003] The commercial application of zinc-ion batteries is mainly limited by the runaway deposition problem of zinc metal anodes. This problem stems from several interrelated inherent contradictions: thermodynamically, zinc's negative potential makes it unstable in aqueous environments, triggering corrosion and hydrogen evolution side reactions; kinetically and in terms of mass transfer, rapid redox reactions at the interface and slow bulk ion diffusion lead to dynamic ion depletion, causing concentration polarization; and in terms of electric field distribution, surface microuniformity causes ions to migrate towards the electric field-concentrated tips, accelerating deposition, while deposition growth further distorts the electric field, forming a positive feedback loop of dendrite self-growth. These intertwined contradictions make it difficult to achieve breakthroughs through single-dimensional improvement strategies.

[0004] Therefore, developing an integrated modification system that combines optimized dual-conductor network design for electron / ion conduction, spontaneous guidance of built-in electric field, adaptive buffering for volume expansion, and protection of the negative electrode interface to achieve multi-dimensional performance synergy is key to overcoming the application challenges of zinc-ion batteries. Summary of the Invention

[0005] To address the shortcomings of existing technologies, a method for preparing a three-dimensional network for regulating the zinc deposition process is provided. This carrier exhibits dual electron / ion conductivity, a robust and interlocked structure, and an endogenous interfacial electric field. When used as the anode of a zinc-ion battery, it significantly overcomes the mismatch problem in electrode mass transfer and charge transfer. Simultaneously, it precisely regulates the entire process of zinc ion adsorption, desolvation, migration, and deposition at the atomic / molecular level, improving the coulombic efficiency of the zinc anode and achieving a highly stable long-cycle process under high current and deep charge / discharge conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution;

[0007] A method for preparing a graphene-COF heterostructured interlocking three-dimensional network material includes the following steps:

[0008] S1. Graphene oxide was functionalized with ethylenediamine via a liquid-phase method:

[0009] S11. The graphene oxide dispersion and ethylenediamine were heated under nitrogen protection and refluxed to obtain solution A;

[0010] S12. Add 1,3,5-tricarboxymethyl phloroglucinol to solution A and stir to obtain solution B;

[0011] S13. Add 2,5-diaminobenzenesulfonic acid and p-toluenesulfonic acid to solution B and stir to obtain a mixed solution;

[0012] S2. Preparation of graphene-two-dimensional π-conjugated COF hydrogel by thermal reduction method: The mixed solution obtained in step S1 is subjected to hydrothermal reaction at a reaction temperature of 80-200℃ and a reaction time of 12-360 hours. After the reaction is completed, the hydrogel is obtained.

[0013] S3. Freeze-dry the hydrogel obtained in step S2 to obtain the graphene-COF heterostructure interlocking three-dimensional network material.

[0014] The graphene-COF heterojunctional three-dimensional network material provided by this invention can be used as a zinc metal anode carrier. This invention first involves the controlled amination and reduction of graphene oxide (GO) to precisely construct an amino functional group distribution on its surface, which serves as the active sites for heterojunction assembly. Then, in solution blending, the enhanced multiple intermolecular forces between the amino groups and the COF precursor drive the oriented adsorption and two-dimensional ordered pre-assembly of COF units on the graphene surface, forming a molecular-level anchor array. Subsequently, through a solvothermal reaction, interfacial covalent condensation and π-plane-induced epitaxial growth are synergistically achieved, crystallizing the COF layer and forming a strongly coupled heterojunction with deeply reduced and structurally repaired graphene at the molecular level. Finally, after freeze-drying and shaping, a dual-continuous conductive network carrier with a stable heterojunction interface, three-dimensional interlocking channels, and an intrinsically built-in electric field is obtained.

[0015] Preferably, in step S11, the concentration of the graphene oxide dispersion is 1-15 mg / mL, and the volume ratio of the graphene oxide dispersion to ethylenediamine is (20-80) mL:(10 μL - 3 mL); the reflux reaction temperature is 35-80°C, and the reflux time is 2-24 hours. More preferably, the reflux reaction temperature is 55-65°C, and the time is 6-8 hours.

[0016] Preferably, in step S12, the stirring speed is 600-1200 rpm, and the stirring time is 0.5-24 hours. More preferably, the stirring speed is 600-1200 rpm, and the stirring time is 2-5 hours.

[0017] Preferably, in step S13, the mass ratio of 1,3,5-tricarboxymethyl phloroglucinol, 2,5-diaminobenzenesulfonic acid, and p-toluenesulfonic acid is 10~500:10~500:60~5000; the stirring speed in step S13 is 600-1200 rpm, and the time is 0.5~24 hours.

[0018] Preferably, in step S2, the temperature of the hydrothermal reaction is 80~200℃, and the reaction time is 12-120 hours.

[0019] Preferably, in step S13, the specific steps of freeze drying are as follows: first, freeze the hydrogel at -18°C for 6-24 hours, and then freeze-dry it at -50°C for 6-120 hours.

[0020] More preferably, in step S2, the temperature of the hydrothermal reaction is 120°C and the reaction time is 24-36 hours.

[0021] More preferably, in step S13, the specific steps of the freeze-drying are as follows: first, freeze the hydrogel at -18°C for 6-24 hours, and then freeze-dry it at -50°C for 40-60 hours.

[0022] This invention also protects the graphene-COF heterogeneous interlocking three-dimensional network material prepared by the method.

[0023] Furthermore, this invention protects the application of the graphene-COF heterostructure interlocking three-dimensional network material in zinc-ion batteries.

[0024] Furthermore, the graphene-COF heterostructured interlocking three-dimensional network material is used for zinc-ion battery anode assembly.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] (1) Advantages of each building block and the coupled heterojunction. Graphene, with its lightweight, high conductivity, and excellent in-plane mechanical properties, provides an ideal electronic conduction and mechanical support framework for the electrode. COF, with its regular and tunable topology, high porosity, and excellent stability, constructs a protective layer at the interface that combines rapid ion transport and high mechanical tolerance, thereby synergistically optimizing zinc deposition kinetics and stabilizing the electrode interface. More importantly, when the two form a strongly coupled heterojunction through π-π stacking and orbital overlap, not only is a continuous cross-interface electronic channel established, but the difference in Fermi level also triggers spontaneous charge transfer and band bending, thereby constructing a directionally stable and spatially localized built-in electric field at the interface. This electric field can provide pre-set electrostatic guidance for the directional adsorption and uniform nucleation of initial zinc ions, fundamentally regulating the deposition behavior.

[0027] (2) Advantages in kinetics and structural stability. At the kinetic level, its continuous electron-ion dual pathway optimizes the mass transfer process, reduces local current density and concentration polarization, and promotes uniform electric field distribution. At the structural stability level, its three-dimensional porous framework provides ample space for zinc deposition, which can directly and effectively buffer the mechanical stress generated by volume expansion, thereby maintaining the structural integrity of the electrode during long-term cycling. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope image of the graphene-coupled COF three-dimensional carrier prepared in Example 1 of the present invention.

[0029] Figure 2 This is an atomic force microscope image of the graphene-coupled COF layered interface obtained in Example 1 of the present invention.

[0030] Figure 3 This is a scanning electron microscope image of the graphene-coupled COF three-dimensional carrier after zinc deposition, prepared in Example 1 of the present invention.

[0031] Figure 4 This is a scanning electron microscope image of zinc deposition on a graphene three-dimensional carrier.

[0032] Figure 5 The graphs show the cycle performance of symmetrical cells assembled from graphene-coupled COF three-dimensional carriers and graphene three-dimensional carriers without COF loading after zinc deposition, as prepared in Example 1 of this invention. Detailed Implementation

[0033] The following specific embodiments of the present invention will provide a detailed and comprehensive description of the technical solutions of the present invention. It should be noted that the provided embodiments represent only a part of the present invention, and not all of it. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods; unless otherwise specified, the materials and reagents used are commercially available reagents and materials, and the commercially available raw materials are used to remove insoluble matter and other impurities by general filtration methods.

[0035] Example 1

[0036] A method for preparing a graphene-COF heterostructured interlocking three-dimensional network material includes the following steps:

[0037] The first step involves functionalizing graphene oxide with ethylenediamine using a liquid-phase method:

[0038] 50 mL of 3 mg / mL GO dispersion was refluxed with 20 μL of ethylenediamine under nitrogen protection at 60 °C for 8 hours to obtain solution A.

[0039] 66 mg of 1,3,5-tricarboxymethyl phloroglucinol was added to solution A, and then stirred continuously for 2 hours at a speed of 1200 rpm to obtain solution B;

[0040] 60.7 mg of 2,5-diaminobenzenesulfonic acid and 0.49 g of p-toluenesulfonic acid were added to solution B, and the mixture was stirred continuously for 2 hours at a speed of 1200 rpm.

[0041] The second step involves preparing a graphene-two-dimensional π-conjugated COF hydrogel using a thermal reduction method.

[0042] The above mixed solution was placed in a hydrothermal reactor for hydrothermal reaction at 120°C for 24 hours. After the reaction, it was cooled to room temperature and then rinsed four times alternately with 60°C deionized water and acetone.

[0043] The third step involves preparing a graphene-two-dimensional π-conjugated COF heterostructured interlocking dual-conductor network using a freeze-drying method.

[0044] The above hydrogel was cut into cylinders with a diameter of 1.2 cm and a height of 6 mm, and frozen at -18°C for 24 hours. Then, it was freeze-dried at -50°C for 48 hours to prepare a graphene-two-dimensional π-conjugated COF heterostructure interlocking dual-conductor network.

[0045] The application of graphene-COF heterostructured interlocking three-dimensional network materials includes the following steps:

[0046] The above-mentioned graphene-two-dimensional π-conjugated COF hetero-interlocked dual-conductor network was compressed into tablets using a tablet press with a pressure of 5 MPa to prepare a functional graphene-coupled COF three-dimensional carrier for zinc metal anode.

[0047] Example 2:

[0048] A method for preparing a graphene-COF heterostructured interlocking three-dimensional network material includes the following steps:

[0049] The first step involves functionalizing graphene oxide with ethylenediamine using a liquid-phase method:

[0050] 50 mL of 3 mg / mL GO dispersion and 1 mL of ethylenediamine were refluxed at 60 °C under nitrogen protection for 8 hours to obtain solution A.

[0051] 66 mg of 1,3,5-tricarboxymethyl phloroglucinol was added to solution A, and then stirred continuously for 2 hours at a speed of 1200 rpm to obtain solution B;

[0052] 60.7 mg of 2,5-diaminobenzenesulfonic acid and 0.49 g of p-toluenesulfonic acid were added to solution B, and the mixture was stirred continuously for 2 hours at a speed of 1200 rpm.

[0053] The second step involves preparing a graphene-two-dimensional π-conjugated COF hydrogel using a thermal reduction method.

[0054] The above mixed solution was placed in a hydrothermal reactor for hydrothermal reaction at 120°C for 24 hours. After the reaction, it was cooled to room temperature and then rinsed four times alternately with 60°C deionized water and acetone.

[0055] The third step involves preparing a graphene-two-dimensional π-conjugated COF heterostructured interlocking dual-conductor network using a freeze-drying method.

[0056] The above hydrogel was cut into cylinders with a diameter of 1.2 cm and a height of 6 mm, and frozen at -18°C for 24 hours. Then, it was freeze-dried at -50°C for 48 hours to prepare a graphene-two-dimensional π-conjugated COF heterostructure interlocking dual-conductor network.

[0057] The application of graphene-COF heterostructured interlocking three-dimensional network materials includes the following steps:

[0058] The above-mentioned graphene-two-dimensional π-conjugated COF hetero-interlocked dual-conductor network was compressed into tablets using a tablet press with a pressure of 5 MPa to prepare a functional graphene-coupled COF three-dimensional carrier for zinc metal anode.

[0059] Example 3:

[0060] A method for preparing a graphene-COF heterostructured interlocking three-dimensional network material includes the following steps:

[0061] The first step involves functionalizing graphene oxide with ethylenediamine using a liquid-phase method:

[0062] 50 mL of 3 mg / mL GO dispersion was refluxed with 10 μL of ethylenediamine under nitrogen protection at 60 °C for 8 hours to obtain solution A.

[0063] 156.7 mg of 1,3,5-tricarboxymethyl phloroglucinol was added to solution A, and then stirred continuously for 5 hours at a speed of 1200 rpm to obtain solution B;

[0064] 210.4 mg of 2,5-diaminobenzenesulfonic acid and 1.2 g of p-toluenesulfonic acid were added to solution B, and the mixture was stirred continuously for 2 hours at a speed of 1200 rpm.

[0065] The second step involves preparing a graphene-two-dimensional π-conjugated COF hydrogel using a thermal reduction method.

[0066] The above mixed solution was placed in a hydrothermal reactor for hydrothermal reaction at 120°C for 36 hours. After the reaction, it was cooled to room temperature and then rinsed four times alternately with 60°C deionized water and acetone.

[0067] The third step involves preparing a graphene-two-dimensional π-conjugated COF heterostructured interlocking dual-conductor network using a freeze-drying method.

[0068] The above hydrogel was cut into cylinders with a diameter of 1.2 cm and a height of 10 mm, and frozen at -18°C for 24 hours. Then, it was freeze-dried at -50°C for 48 hours to prepare a graphene-two-dimensional π-conjugated COF heterostructure interlocking dual-conductor network.

[0069] The application of graphene-COF heterostructured interlocking three-dimensional network materials includes the following steps:

[0070] The above-mentioned graphene-two-dimensional π-conjugated COF hetero-interlocked dual-conductor network was compressed into tablets using a tablet press with a pressure of 10 MPa to prepare a functional graphene-coupled COF three-dimensional carrier for zinc metal anode.

[0071] Figure 1 This is a scanning electron microscope (SEM) image of the graphene-coupled COF three-dimensional carrier prepared in Example 1 of this invention. Analysis of the cross-sectional SEM images reveals a cross-linked, interconnected three-dimensional layered stacked structure within the carrier. The graphene and COF are uniformly coupled without aggregation, and the overall thickness of the carrier is consistent.

[0072] Figure 2 This is an atomic force microscopy (AFM) image of the graphene-coupled COF layered interface obtained in Example 1 of this invention. Analysis of the AFM image shows that the reduced graphene layer and the COF layer are tightly coupled, forming a stacked layered structure. The thickness of the reduced graphene sheet is approximately 1.7 nm, and the thickness of the COF layer is approximately 5.3 nm.

[0073] Figure 3 This is a scanning electron microscope (SEM) image of the graphene-coupled COF three-dimensional carrier zinc deposition obtained in Example 1 of this invention. Based on the SEM observations, at a current density of 2 mAh cm⁻¹... -2 Under these conditions, 12 mAh cm -2 No zinc dendrites were observed to form after zinc was deposited on a graphene-coupled COF three-dimensional support. The zinc metal was uniformly deposited in the lamellar framework of the support and confined within its layered channels. At the same time, the volume remained stable during the deposition process and no significant expansion occurred.

[0074] Figure 4 This is a scanning electron microscope (SEM) image of zinc deposition on a graphene-based three-dimensional carrier as described in Example 1. Based on the SEM observations, at a current density of 2 mAh cm⁻¹... -2 Under these conditions, 12 mAh cm -2 When metallic zinc is deposited on a graphene-coupled COF three-dimensional support, due to the lack of a built-in electric field for guidance, zinc tends to be deposited on the top of the support rather than in the confined space inside.

[0075] Figure 5 The figures show the cycling performance of symmetrical cells assembled from graphene-coupled COF three-dimensional supports and graphene three-dimensional supports without COF loading, respectively, after zinc deposition, as shown in Example 1 of this invention. The long-cycle results of the symmetrical cells show that at a current density of 2 mAh cm⁻¹, [the cells exhibit excellent performance]. -2 Under the specified conditions, the graphene-coupled COF composite zinc metal material can be stably cycled for over 2000 hours, while the comparative material, the graphene-coated zinc metal material, only lasts for 700 hours before failing. This result demonstrates that the graphene-COF coupling structure effectively improves the cycle stability of the zinc metal anode.

[0076] Obviously, the above embodiments of the present invention are merely examples to clearly illustrate the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a graphene-COF heterostructured interlocking three-dimensional network material, characterized in that, Includes the following steps: S1. Graphene oxide was functionalized with ethylenediamine via a liquid-phase method: S11. The graphene oxide dispersion and ethylenediamine were heated under nitrogen protection and refluxed to obtain solution A; S12. Add 1,3,5-tricarboxymethyl phloroglucinol to solution A and stir to obtain solution B; S13. Add 2,5-diaminobenzenesulfonic acid and p-toluenesulfonic acid to solution B and stir to obtain a mixed solution; S2. Preparation of graphene-two-dimensional π-conjugated COF hydrogel by thermal reduction method: The mixed solution obtained in step S1 is subjected to hydrothermal reaction at a reaction temperature of 80-200℃ and a reaction time of 12-360 hours. After the reaction is completed, the hydrogel is obtained. S3. Freeze-dry the hydrogel obtained in step S2 to obtain the graphene-COF heterostructure interlocking three-dimensional network material.

2. The preparation method according to claim 1, characterized in that, In step S11, the concentration of the graphene oxide dispersion is 1-15 mg / mL, and the volume ratio of the graphene oxide dispersion to ethylenediamine is (20-80) mL: (10 μL - 3 mL); the temperature of the reflux reaction is 35-80℃, and the reflux time is 2-24 hours.

3. The preparation method according to claim 1, characterized in that, In step S12, the stirring speed is 600-1200 rpm, and the time is 0.5-24 hours.

4. The preparation method according to claim 1, characterized in that, In step S13, the mass ratio of 1,3,5-tricarboxymethyl phloroglucinol, 2,5-diaminobenzenesulfonic acid, and p-toluenesulfonic acid is 10~500:10~500:60~5000; the stirring speed in step S13 is 600-1200 rpm, and the time is 0.5~24 hours.

5. The preparation method according to claim 1, characterized in that, In step S2, the temperature of the hydrothermal reaction is 80~200℃, and the reaction time is 12-120 hours.

6. The preparation method according to claim 1, characterized in that, In step S13, the specific steps of freeze drying are as follows: first, freeze the hydrogel at -18°C for 6-24 hours, and then freeze-dry it at -50°C for 6-120 hours.

7. A graphene-COF heterostructured interlocking three-dimensional network material prepared by the method according to any one of claims 1-6.

8. The application of the graphene-COF heterogeneous interlocking three-dimensional network material according to claim 7 in zinc-ion batteries.

9. The application according to claim 8, characterized in that, The graphene-COF heterostructured interlocking three-dimensional network material is used for zinc-ion battery anode assembly.

Images