Zinc anode based on organic molecule adsorption layer and preparation method and application thereof

Abstract

The invention belongs to the field of aqueous zinc ion energy storage devices, and particularly relates to a zinc anode based on an organic molecule adsorption layer and a preparation method and application thereof, and the preparation method comprises the following steps: uniformly coating the surface of a zinc electrode with an organic molecule solution, and carrying out vacuum drying to obtain the zinc anode; the organic molecules are any one or more of dithizone, terephthalonitrile, dimethylglyoxime and phenanthroline. Organic molecules are strongly adsorbed on the surface of a zinc anode through functional groups of the organic molecules, interface modification is performed by establishing a protective layer between a zinc cathode and electrolyte, uniform nucleation sites are provided, zinc ions are guided to be uniformly deposited, dendritic crystal formation is avoided, and therefore the purpose of inhibiting zinc dendritic crystal growth is achieved.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc ion energy storage devices, specifically relating to a zinc anode based on an organic molecular adsorption layer, its preparation method, and its application. Background Technology

[0002] Against the backdrop of the global energy system's transition to cleaner and lower-carbon energy, developing efficient, safe, and sustainable energy storage technologies and devices has become a common goal for both academia and industry. Zinc metal, due to its high theoretical specific capacity, abundant reserves, and high safety performance, is considered an ideal anode material for aqueous zinc-ion energy storage devices. However, aqueous zinc-ion batteries face the problem of zinc anode failure in practical applications. During repeated charge and discharge cycles, zinc ions tend to preferentially deposit in localized high-current-density areas on the electrode surface, forming sharp dendritic structures. The growth of these dendrites can lead to internal short circuits, capacity decay, and even puncture of the separator, causing permanent battery failure.

[0003] To address the problem of dendrite growth in zinc anodes, researchers have proposed various strategies, such as electrolyte composition optimization, three-dimensional electrode structure design, and artificial interface layer construction. However, these methods have limited effectiveness. Therefore, developing an interface modification technique that can effectively induce uniform zinc deposition is of great significance for promoting the commercial application of zinc metal batteries. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a zinc anode based on an organic molecular adsorption layer, its preparation method, and its application.

[0005] A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: A solution of organic molecules is uniformly coated on the surface of a zinc electrode and then dried under vacuum to obtain the zinc anode. The organic molecule is any one or more of dithizone, terephthalonitrile, dimethylglyoxime, and o-phenanthroline.

[0006] This invention involves coating an organic molecule onto the surface of a zinc electrode. This organic molecule contains multiple strongly coordinating atoms that can form stable coordination bonds with zinc ions, thereby inducing uniform zinc ion deposition and constructing a stable zinc-loving interface. The organic molecule possesses a planar or extended conjugated structure, such as a benzene ring or conjugated double bonds, allowing it to spread across the zinc electrode surface through π-π stacking or van der Waals forces, forming a dense and uniform adsorption film. This film effectively eliminates the inherent chemical inhomogeneity of the zinc surface, providing uniform nucleation sites for zinc deposition, thus guiding uniform zinc ion deposition and preventing dendrite formation.

[0007] And the organic molecules and Zn 2+The coordination is dynamic and reversible; when zinc deposition occurs, the coordination bonds can break and recombine without permanently blocking the electrode surface.

[0008] Preferably, the organic molecules are dissolved in an organic solvent in the solution of the organic molecules; The organic solvent is any one or more of chloroform, dichloromethane, and acetone. The organic molecules dissolve in these solvents, which evaporate quickly, thus rapidly forming an organic molecule adsorption layer on the zinc electrode surface.

[0009] Preferably, the concentration of the organic molecule solution is between 5 mg / mL and 25 mg / mL. The concentration affects the amount of organic molecules coated on the zinc electrode surface, and experiments have shown that the maximum solubility of the organic molecules in the organic solvent is approximately 25 mg / mL.

[0010] Preferably, the zinc electrode is pre-cleaned using ultrasonic cleaning to remove the surface oxide layer.

[0011] Preferably, the zinc electrode is a zinc foil, zinc rod, zinc mesh, or a conductive material deposited with zinc metal.

[0012] Preferably, the coating method includes any one of drip coating, spin coating, spray coating, and blade coating.

[0013] Preferably, the volume of the solution containing the coated organic molecules is 5 μL / cm³. 2 ~30μL / cm 2 Volume affects the amount of organic molecules coated on the zinc electrode surface.

[0014] A zinc anode prepared by the method described above.

[0015] The application of the zinc anode as a negative electrode material in the preparation of aqueous zinc ion energy storage devices.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The organic molecules in the modified layer of this invention are strongly adsorbed onto the zinc anode surface through their functional groups. By establishing a protective layer between the zinc anode and the electrolyte, the interface is modified to provide uniform nucleation sites, guide the uniform deposition of zinc ions, and avoid dendrite formation, thereby achieving the purpose of inhibiting zinc dendrite growth.

[0017] The solution coating method described in this invention has low equipment requirements, is simple to operate, and is easy to scale up for production, which greatly reduces the cost of zinc anode surface modification.

[0018] The symmetrical zinc battery assembled with an organically adsorbed zinc anode in this invention maintains a capacity of 1 mAh / cm³. 2 2mA / cm 2Under the test conditions, the symmetrical battery assembled thereon has a cycle life of over 1000 hours, and the cycle stability has been significantly improved. Attached Figure Description

[0019] Figure 1 The elemental distribution diagram is shown for the zinc anode with a dithizone adsorption layer prepared in Example 1.

[0020] Figure 2 To observe the zinc anode with a dithizone adsorption layer prepared in Example 1 using an in-situ optical microscope, an applied current density of 20 mA / cm² was used. 2 Cross-sectional morphology images were obtained at deposition times of 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min.

[0021] Figure 3 The elemental distribution diagram is shown for the zinc anode with a terephthalonitrile adsorption layer prepared in Example 2.

[0022] Figure 4 The images show the surface microstructure of the zinc anode with a terephthalonitrile adsorption layer prepared in Example 2 before and after a 1000-cycle stability test.

[0023] Figure 5 The image shows the cycle stability test results of a symmetrical zinc battery assembled from a zinc anode with a dimethylglyoxime adsorption layer prepared in Example 3.

[0024] Figure 6 The image shows the cycle stability test results of a symmetrical zinc battery assembled from a zinc anode with an o-phenanthroline adsorption layer prepared in Example 4.

[0025] Figure 7 To observe the zinc anode with a polyvinylidene fluoride adsorption layer prepared in Comparative Example 1 using an in-situ optical microscope at an applied current density of 20 mA / cm² 2 Cross-sectional morphology images were obtained at deposition times of 0 min, 10 min, 20 min, 30 min, and 40 min.

[0026] Figure 8 The image shows the cycle stability test results of a symmetrical zinc battery assembled from a zinc anode with a pyrene adsorption layer prepared in Comparative Example 2. Detailed Implementation

[0027] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. 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. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods.

[0028] Example 1 A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: Dithizone was dissolved in chloroform to prepare a dithizone-chloroform solution with a concentration of 10 mg / mL.

[0029] For an area of ​​1×1cm 2 Commercial zinc foil is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0030] A 10 μL dithizone-chloroform solution was uniformly coated onto the surface of a zinc anode using a drop-coating method, followed by vacuum drying to obtain a zinc anode with a dithizone adsorption layer.

[0031] Figure 1 This is an elemental distribution diagram of the zinc anode with a dithizone adsorption layer prepared in Example 1 of the present invention. As can be seen from the diagram, sulfur and nitrogen elements, which are related to dithizone, are evenly distributed, indicating that dithizone is uniformly adsorbed on the zinc foil.

[0032] Figure 2 To observe the zinc anode with a dithizone adsorption layer prepared in Example 1 of this invention using an in-situ optical microscope at an applied current density of 20 mA / cm², 2 Cross-sectional morphology images were obtained at deposition times of 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min. With increasing deposition time, no zinc dendrite growth was observed on the zinc anode, while a large number of zinc dendrites were observed on the zinc anode without a dithizone adsorption layer, indicating that the presence of the dithizone adsorption layer successfully suppressed zinc dendrite formation.

[0033] Example 2 A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: Terephthalonitrile was dissolved in dichloromethane to prepare a 10 mg / mL terephthalonitrile-dichloromethane solution.

[0034] For an area of ​​1×1cm 2 Commercial zinc foil is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0035] A zinc anode with a terephthalonitrile-dichloromethane solution was uniformly coated onto the surface of the zinc anode using a spin-coating method and then dried under vacuum to obtain a zinc anode with a terephthalonitrile adsorption layer.

[0036] Figure 3 This is an elemental distribution diagram of the zinc anode with a terephthalonitrile adsorption layer prepared in Embodiment 2 of the present invention. As can be seen from the diagram, nitrogen, an element associated with terephthalonitrile, is evenly distributed, indicating that terephthalonitrile is uniformly adsorbed on the zinc foil.

[0037] Figure 4 The images show the surface microstructure of the zinc anode with a terephthalonitrile adsorption layer prepared in Example 2 of this invention before and after a 1000-cycle stability test. As can be seen from the images, the zinc anode with the terephthalonitrile adsorption layer maintains a smooth surface morphology after the cycle stability test, and no zinc dendrite formation is observed. In contrast, the zinc anode without the terephthalonitrile adsorption layer shows a large number of zinc dendrites after the cycle stability test, indicating that the presence of the terephthalonitrile adsorption layer can induce uniform zinc deposition and inhibit zinc dendrite formation.

[0038] Example 3 A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: Dimethylglyoxime was dissolved in acetone to prepare a 15 mg / mL dimethylglyoxime-acetone solution.

[0039] For an area of ​​1×1cm 2 Commercial zinc mesh is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0040] A zinc anode with a dimethylglyoxime-acetone solution was uniformly coated onto the surface of the zinc anode using a drop-coating method and then dried under vacuum to obtain a zinc anode with a dimethylglyoxime adsorption layer.

[0041] Figure 5 This is a cycle stability test diagram of a symmetrical zinc battery assembled from a zinc anode with a dimethylglyoxime adsorption layer prepared in Example 3 of the present invention. The test conditions were 5 mA / cm². 2 1mAh / cm 2 At that time, symmetrical zinc batteries assembled with zinc anodes having a dimethylglyoxime adsorption layer could cycle stably for more than 900 hours, while symmetrical zinc batteries assembled with zinc anodes without an adsorption layer would be damaged after about 50 hours.

[0042] Example 4 A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: Dissolve o-phenanthroline in acetone to prepare an o-phenanthroline-acetone solution with a concentration of 15 mg / mL.

[0043] For an area of ​​1×1cm 2 The carbon cloth loaded with zinc metal was cleaned with ethanol to remove the surface oxide layer and then dried.

[0044] A zinc anode with an o-phenanthroline adsorption layer was obtained by uniformly coating 15 μL of o-phenanthroline-acetone solution onto the surface of the zinc anode using a spraying method and then vacuum drying.

[0045] Figure 6This is a cycle stability test diagram of a symmetrical zinc battery assembled from a zinc anode with an o-phenanthroline adsorption layer prepared in Example 4 of this invention. The test conditions were 2 mA / cm². 2 1mAh / cm 2 At that time, symmetrical zinc batteries assembled with zinc anodes having o-phenanthroline adsorption layers could cycle stably for more than 1000 hours, while symmetrical zinc batteries assembled with zinc anodes without adsorption layers would be damaged after about 100 hours.

[0046] Example 5 A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: Dithizone was dissolved in chloroform to prepare a dithizone-chloroform solution with a concentration of 5 mg / mL.

[0047] For an area of ​​1×1cm 2 Commercial zinc foil is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0048] A 20 μL dithizone-chloroform solution was uniformly coated onto the surface of a zinc anode using a drop-coating method, followed by vacuum drying to obtain a zinc anode with a dithizone adsorption layer.

[0049] Example 6 A method for preparing a zinc anode based on an organic molecular adsorption layer includes the following steps: Dithizone was dissolved in chloroform to prepare a dithizone-chloroform solution with a concentration of 25 mg / mL.

[0050] For an area of ​​1×1cm 2 Commercial zinc foil is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0051] A 30 μL dithizone-chloroform solution was uniformly coated onto the surface of a zinc anode using a drop-coating method, followed by vacuum drying to obtain a zinc anode with a dithizone adsorption layer.

[0052] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the dithizone-chloroform solution was replaced with a polyvinylidene fluoride-N,N-dimethylformamide solution, as detailed below: For an area of ​​1×1cm 2 Commercial zinc foil is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0053] A zinc anode with a polyvinylidene fluoride-N,N-dimethylformamide solution of 10 mg / mL was uniformly coated onto the surface of the zinc anode using a drop-coating method and then dried under vacuum to obtain a zinc anode with a polyvinylidene fluoride adsorption layer.

[0054] Figure 7To observe the zinc anode with a polyvinylidene fluoride adsorption layer prepared in Comparative Example 1 using an in-situ optical microscope at an applied current density of 20 mA / cm² 2 Cross-sectional morphology images were taken at deposition times of 0 min, 10 min, 20 min, 30 min, and 40 min. As deposition time increased, the zinc anode gradually became uneven and developed protrusions.

[0055] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the dithizone-chloroform solution is replaced with a pyrene-ethanol solution, as follows: For an area of ​​1×1cm 2 Commercial zinc foil is ultrasonically cleaned to remove the surface oxide layer and then dried.

[0056] A zinc anode with a pyrene adsorption layer was obtained by uniformly coating 10 μL of a 10 mg / mL pyrene-ethanol solution onto the surface of the zinc anode using a drop-coating method and then drying under vacuum.

[0057] Figure 8 This is a cycle stability test diagram of a symmetrical zinc battery assembled from a zinc anode with a pyrene adsorption layer prepared in Comparative Example 2 of this invention. The test conditions were 1 mA / cm². 2 0.5mAh / cm 2 At that time, symmetrical zinc batteries assembled with zinc anodes having pyrene adsorption layers were damaged after more than 130 hours of cycling, while symmetrical zinc batteries assembled with zinc anodes having phthalonitrile adsorption layers could cycle stably for nearly 600 hours.

[0058] It should be noted that when numerical ranges are mentioned in the claims of this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. To avoid redundancy, the present invention describes preferred embodiments.

[0059] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0060] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a zinc anode based on an organic molecular adsorption layer, characterized in that, Includes the following steps: A solution of organic molecules is uniformly coated on the surface of a zinc electrode and then dried under vacuum to obtain the zinc anode. The organic molecule is any one or more of dithizone, terephthalonitrile, dimethylglyoxime, and o-phenanthroline.

2. The preparation method according to claim 1, characterized in that, The organic molecules are dissolved in an organic solvent in a solution of the organic molecules; The organic solvent is any one or more of chloroform, dichloromethane, and acetone.

3. The preparation method according to claim 2, characterized in that, The concentration of the organic molecule solution is 5 mg / mL to 25 mg / mL.

4. The preparation method according to claim 1, characterized in that, The zinc electrode is pre-cleaned using ultrasonic cleaning to remove the surface oxide layer.

5. The preparation method according to claim 1, characterized in that, The zinc electrode is a zinc foil, zinc rod, zinc mesh, or a conductive material with zinc metal deposited on it.

6. The preparation method according to claim 1, characterized in that, The coating method includes any one of the following: drop coating, spin coating, spray coating, and blade coating.

7. The preparation method according to claim 1, characterized in that, The volume of the solution coated with organic molecules is 5 μL / cm³. 2 ~30μL / cm 2 .

8. A zinc anode prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the zinc anode as described in claim 8 as a negative electrode material in the preparation of an aqueous zinc ion energy storage device.

Images