Zinc negative electrode, method for preparing the same, and zinc-air battery

Abstract

The application provides a zinc negative electrode and a preparation method thereof and a zinc-air battery, and particularly relates to the technical field of zinc-air batteries. The zinc negative electrode comprises a zinc foil and a monomolecular layer self-assembled on the surface of the zinc foil; wherein the material of the monomolecular layer is a mercapto compound containing a benzene ring. The zinc negative electrode provided by the application has the monomolecular layer self-assembled on the zinc foil, the mercapto group in the mercapto compound containing a benzene ring reacts with the zinc foil to generate a Zn-S bond and stably exists on the surface of the zinc foil, meanwhile, has a metallophilic tail group -SH, guides the uniform deposition nucleation of zinc ions in an electrochemical reaction, and isolates water molecules, thereby effectively inhibiting dendrite growth. In addition, the mercapto compound containing a benzene ring has good ionic conductivity, effectively inhibits the problem of high interfacial resistance of the coating, and ensures good ionic conductivity between the zinc negative electrode and the electrolyte.

Description

Technical Field

[0001] This invention relates to the field of metal-air battery technology, and in particular to a zinc anode, its preparation method, and a zinc-air battery. Background Technology

[0002] With the increasing severity of energy security and environmental issues, the development of high-energy-density and high-safety energy storage systems is imperative. Zinc-air batteries have attracted widespread attention due to their high energy density, high safety, and low cost. However, problems related to the zinc anode, such as hydrogen evolution, corrosion, passivation, dendrite formation, and deformation, lead to low coulombic efficiency and short cycle life in zinc-air batteries, becoming the main obstacles to their development.

[0003] Currently, common solutions for zinc anodes can be categorized into anode electrode structure design, interface engineering, and electrolyte optimization. Among these, coating modification is one of the more effective methods. Coating methods in zinc battery anode modification offer many significant advantages, including suppressing zinc dendrite growth, reducing side reactions, improving interface stability, enhancing electrochemical performance, promoting uniform current distribution, strengthening mechanical stability, and enabling multifunctional design. Coatings can form a physical barrier, effectively suppressing zinc dendrite growth, preventing short circuits and battery failure, preventing direct contact between zinc and the electrolyte, reducing side reactions (such as zinc corrosion and hydrogen evolution), thereby improving the battery's coulombic efficiency and cycle life; they can improve the stability of the zinc anode-electrolyte interface, reducing interface impedance changes and maintaining battery stability; and they can promote uniform current distribution, reducing dendrite growth and electrode wear caused by excessively high local current densities. These advantages significantly improve the battery's cycle life and performance.

[0004] However, coating methods still face certain challenges, including coating uniformity issues, insufficient adhesion, increased interfacial resistance, insufficient chemical stability, and complex processes. These drawbacks may limit the effectiveness and application range of the coating. Coating inhomogeneity leads to uneven current density distribution, which in turn induces localized zinc dendrite growth. Uneven coating thickness affects the electrochemical performance and stability of the electrode; insufficient adhesion between the coating material and the zinc substrate makes it prone to detachment during battery charge-discharge cycles, thus losing its protective effect. Insufficient mechanical strength and toughness of the coating make it susceptible to cracking or peeling during repeated volume changes (such as charge-discharge); the coating material may increase the interfacial resistance between the zinc anode and the electrolyte, reducing the overall conductivity and power performance of the battery; the ionic conductivity of the coating material is usually lower than that of the electrolyte, which may limit ion transport speed and affect the battery's charge-discharge efficiency. The chemical stability of the coating material in the electrochemical environment may be insufficient, leading to degradation over long-term use and weakened protective effects. Some coating materials have poor stability in the electrolyte and may dissolve or react, causing coating failure. The coating process may involve complex manufacturing processes, increasing production costs and time.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] One of the objectives of this invention is to provide a zinc anode that addresses at least one of the aforementioned technical problems in the prior art.

[0007] The second objective of this invention is to provide a method for preparing a zinc anode.

[0008] The third objective of this invention is to provide a zinc-air battery.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] A first aspect of the present invention provides a zinc negative electrode comprising a zinc foil and a monolayer self-assembled on the surface of the zinc foil;

[0011] The monolayer is made of a thiol compound containing a benzene ring.

[0012] Furthermore, the thiol compound containing a benzene ring includes at least one of thiols, thiophenols, and thiocarboxylic acids.

[0013] Preferably, the thiol includes 1,4-phenyldithiol.

[0014] Preferably, the thiophenol includes at least one of benzylthiophenol, 4-hydroxybenzylthiophenol, and 4-mercaptobenzylthiophenol.

[0015] Preferably, the thiocarboxylic acid includes 4-mercaptobenzoic acid.

[0016] A second aspect of the present invention provides a method for preparing the zinc anode described in the first aspect, comprising the following steps:

[0017] Zinc foil is immersed in a solution of a thiol compound containing benzene rings, and the thiol compound containing benzene rings self-assembles on the surface of the zinc foil to obtain the zinc negative electrode.

[0018] Furthermore, the concentration of the thiol compound solution is 0.01M to 0.1M.

[0019] Preferably, the soaking time is 12h to 48h.

[0020] Furthermore, the preparation method also includes pretreatment of the zinc foil before impregnation;

[0021] The pretreatment includes grinding, cleaning, and drying of the zinc foil.

[0022] Further, the sanding is performed using sandpaper.

[0023] Preferably, the roughness of the sandpaper is 800 mesh to 2000 mesh.

[0024] Furthermore, the cleaning process includes organic solvent cleaning and deionized water rinsing performed in sequence.

[0025] Preferably, the organic solvent includes acetone and / or alcohol.

[0026] Preferably, the organic solvent cleaning method is ultrasonic cleaning.

[0027] Preferably, the ultrasonic cleaning time is 10 min to 20 min.

[0028] Preferably, the deionized water rinsing is performed 2 to 5 times.

[0029] Furthermore, the drying process is carried out under nitrogen protection.

[0030] A third aspect of the present invention provides a zinc-air battery, comprising a positive electrode, a negative electrode, and an electrolyte;

[0031] The negative electrode is the zinc negative electrode described in the first aspect.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] The zinc anode provided by this invention has a self-assembled monolayer on a zinc foil. The thiol groups in a thiol compound containing a benzene ring react with the zinc foil to form Zn-S bonds, thus stably existing on the zinc foil surface. Simultaneously, it possesses a metal-philic tail group (-SH), which guides the uniform deposition and nucleation of zinc ions during the electrochemical reaction, isolating water molecules and effectively inhibiting dendrite growth. Furthermore, the thiol compound containing the benzene ring exhibits good ionic conductivity, effectively suppressing the problem of high interfacial resistance in the coating and ensuring good ionic conductivity between the zinc anode and the electrolyte.

[0034] The zinc anode preparation method provided by this invention forms a monolayer on the zinc foil surface through impregnation and self-assembly, eliminating the need for complex equipment or energy-intensive processes, making the preparation process simple and convenient. The self-assembly of thiol compounds containing benzene rings on the zinc foil surface can form a uniform and tightly packed monolayer, which facilitates the uniform growth of the zinc deposition layer during electrochemical reactions, thereby improving battery performance. This preparation method exhibits excellent reproducibility, improving the consistency and reliability of the zinc anode.

[0035] The zinc-air battery provided by this invention, given the advantages of the zinc anode, results in a zinc-air battery with better stability, efficiency, and safety, expanding the application areas of zinc-air batteries and promoting the development of downstream industries. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 The Fourier transform infrared characterization image obtained from test example 1;

[0038] Figure 2 This is a SEM image of the zinc negative electrode obtained in Example 1 after immersion.

[0039] Figure 3 This is another SEM image of the zinc negative electrode obtained in Example 1 after immersion;

[0040] Figure 4 This is a SEM image of the zinc negative electrode obtained in Comparative Example 1 after immersion.

[0041] Figure 5 This is another SEM image of the zinc negative electrode obtained in Comparative Example 1 after immersion;

[0042] Figure 6 The Tafel curve obtained from test example 3;

[0043] Figure 7 The image shows the SEM image of the zinc anode obtained in Comparative Example 1.

[0044] Figure 8 This is a SEM image of the zinc layer deposited on the zinc anode obtained in Comparative Example 1 after 5 minutes.

[0045] Figure 9 SEM image of the zinc layer deposited on the zinc anode obtained in Comparative Example 1 after 10 min;

[0046] Figure 10 The image shows the SEM image of the zinc anode obtained in Example 1.

[0047] Figure 11 This is a SEM image of the zinc layer deposited on the zinc anode obtained in Example 1 after 5 minutes.

[0048] Figure 12 This is a SEM image of the zinc layer deposited on the zinc anode obtained in Example 1 after 10 minutes. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages 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 embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0050] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0051] A first aspect of the present invention provides a zinc negative electrode comprising a zinc foil and a monolayer self-assembled on the surface of the zinc foil;

[0052] The monolayer is made of a thiol compound containing a benzene ring.

[0053] The zinc anode provided by this invention has a self-assembled monolayer on a zinc foil. The thiol groups in a thiol compound containing a benzene ring react with the zinc foil to form Zn-S bonds, thus stably existing on the zinc foil surface. Simultaneously, it possesses a metal-philic tail group (-SH), which guides the uniform deposition and nucleation of zinc ions during the electrochemical reaction, isolating water molecules and effectively inhibiting dendrite growth. Furthermore, the thiol compound containing the benzene ring exhibits good ionic conductivity, effectively suppressing the problem of high interfacial resistance in the coating and ensuring good ionic conductivity between the zinc anode and the electrolyte.

[0054] Specifically, the zinc anode structure provided by this invention has the following technical effects:

[0055] 1. Improved battery stability: The introduction of a monolayer reduces uneven dissolution and deposition of the zinc anode during the electrochemical reaction process, thereby extending the battery's lifespan.

[0056] 2. Improve battery cycle efficiency: Thiol compounds containing benzene rings, as monolayer materials, can provide better electron and ion transport channels, promote the uniform deposition and dissolution of zinc ions, thereby improving the battery's charge and discharge efficiency.

[0057] 3. Enhanced electrode surface protection: The monolayer acts as a protective layer to prevent the zinc anode from being directly exposed to the electrolyte, reducing side reactions such as hydrogen generation and excessive zinc dissolution.

[0058] 4. Improve battery safety: By controlling the formation of zinc deposits in the electrochemical reaction, dendrite growth can be reduced, lowering the risk of battery short circuits and thus improving battery safety performance.

[0059] 5. Optimize electrode interface: The use of monolayer can improve the interfacial compatibility between zinc anode and electrolyte, reduce interfacial resistance, and improve the overall performance of battery.

[0060] Using a monolayer as a zinc anode coating can effectively avoid some of the shortcomings of traditional coatings, as follows:

[0061] 1. Uniformity: Monolayers can form a highly ordered and uniform monolayer structure on the zinc surface through a self-assembly process, avoiding the problem of uneven coating.

[0062] 2. Excellent adhesion: The monolayer adheres firmly to the zinc surface through chemical bonds or physical adsorption, providing strong adhesion and avoiding the problem of easy peeling of traditional coatings.

[0063] 3. Low interfacial resistance: The monolayer thickness is only a few nanometers, which does not significantly increase the interfacial resistance and ensures good ion conductivity between the zinc anode and the electrolyte.

[0064] 4. Chemical stability.

[0065] 5. Monolayer materials can improve the chemical stability of zinc anodes under electrochemical conditions and reduce degradation and failure.

[0066] 6. Simplified Process and Cost: The self-assembly process of monolayers is generally simple and easy to control, reducing the complexity and cost of manufacturing processes. Through these advantages, monolayers, as zinc anode coatings, excel in suppressing dendrite growth, reducing side reactions, and improving battery performance and cycle life, effectively overcoming many of the shortcomings of traditional coatings.

[0067] The thiol compound containing a benzene ring is a compound having both a thiol group and a benzene ring.

[0068] Furthermore, the thiol compound containing a benzene ring includes at least one of thiols, thiophenols, and thiocarboxylic acids.

[0069] Preferably, the thiol includes 1,4-phenyldithiol.

[0070] Preferably, the thiophenol includes at least one of benzylthiophenol, 4-hydroxybenzylthiophenol, and 4-mercaptobenzylthiophenol.

[0071] Preferably, the thiocarboxylic acid includes 4-mercaptobenzoic acid.

[0072] A second aspect of the present invention provides a method for preparing the zinc anode described in the first aspect, comprising the following steps:

[0073] Zinc foil is immersed in a solution of a thiol compound, which then self-assembles on the surface of the zinc foil to obtain the zinc negative electrode.

[0074] The zinc anode preparation method provided by this invention forms a monolayer on the zinc foil surface through impregnation and self-assembly, eliminating the need for complex equipment or energy-intensive processes, making the preparation process simple and convenient. The self-assembly of thiol compounds containing benzene rings on the zinc foil surface can form a uniform and tightly packed monolayer, which facilitates the uniform growth of the zinc deposition layer during electrochemical reactions, thereby improving battery performance. This preparation method exhibits excellent reproducibility, improving the consistency and reliability of the zinc anode.

[0075] Furthermore, the concentration of the solution containing the benzene ring mercapto compound is 0.01M to 0.1M.

[0076] If the concentration of a solution containing a benzene ring thiol compound is below 0.01 M, the thiol loading will be insufficient; if the concentration of a solution containing a benzene ring thiol compound is above 0.1 M, it exceeds the solubility and affects the uniform distribution of thiol groups.

[0077] Typical, but not limiting, concentrations of solutions containing benzene ring-containing mercapto compounds can be, for example, 0.01 M, 0.05 M, 0.1 M, or any value in the range of 0.01 M to 0.1 M.

[0078] Preferably, the soaking time is 12h to 48h.

[0079] Impregnation time of less than 12 hours will result in insufficient thiol loading, affecting the modification effect; impregnation time of more than 48 hours will reduce production efficiency and output, and increase production costs.

[0080] Typical, but not limiting, the immersion time can be, for example, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h or 48h, or any value within the range of 12h to 48h.

[0081] Furthermore, the preparation method also includes pretreatment of the zinc foil before impregnation;

[0082] The pretreatment includes grinding, cleaning, and drying of the zinc foil.

[0083] Further, the sanding is performed using sandpaper.

[0084] Polishing removes the oxide layer from the zinc foil surface, exposing a fresh metal surface. This freshly exposed zinc surface has higher surface energy and reactivity, which helps self-assembled molecules bind more stably and uniformly. The polished surface provides a more stable chemical bonding environment, enhancing the interaction between self-assembled molecules and the metal surface. The smooth and fresh zinc surface also promotes the orderly arrangement of self-assembled molecules, improving the density and protective effect of the film.

[0085] Preferably, the roughness of the sandpaper is 800 mesh to 2000 mesh.

[0086] Furthermore, the cleaning process includes organic solvent cleaning and deionized water rinsing performed in sequence.

[0087] Organic solvent cleaning removes sandpaper residue and other impurities from the zinc foil.

[0088] Preferably, the organic solvent includes acetone and / or alcohol.

[0089] Preferably, the organic solvent cleaning method is ultrasonic cleaning.

[0090] Preferably, the ultrasonic cleaning time is 10 min to 20 min.

[0091] Typical, but not limiting, ultrasonic cleaning time can be, for example, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min or 20 min, or any value within the range of 10 min to 20 min.

[0092] Preferably, the deionized water rinsing is performed 2 to 5 times.

[0093] Typical, but not limiting, the number of deionized water rinses can be, for example, 2, 3, 4 or 5 times, or any value within the range of 2 to 5 times.

[0094] Furthermore, the drying process is carried out under nitrogen protection.

[0095] A third aspect of the present invention provides a zinc-air battery, comprising a positive electrode, a negative electrode, and an electrolyte;

[0096] The negative electrode is the zinc negative electrode described in the first aspect.

[0097] The zinc-air battery provided by this invention, given the advantages of the zinc anode, results in a zinc-air battery with better stability, efficiency, and safety, expanding the application areas of zinc-air batteries and promoting the development of downstream industries.

[0098] The present invention is further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for illustrative purposes and should not be construed as limiting the invention in any way. Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present invention were carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0099] Example 1

[0100] This embodiment provides a zinc anode, and the specific preparation method is as follows:

[0101] 1. Polish the surface of a 1.5cm×1.5cm commercial zinc foil with 1500 grit sandpaper, then clean the surface with acetone and alcohol for 15 minutes in sequence to remove sandpaper residue and other impurities on the zinc foil. Rinse three times with deionized water, dry under nitrogen, and store under vacuum as a substrate material for subsequent in-situ growth of thiol monolayers.

[0102] 2. The pretreated zinc sheet was immersed in a 0.05M 1,4-phenyldithiol ethanol solution for 36 hours to obtain a zinc negative electrode.

[0103] Example 2

[0104] This embodiment provides a zinc negative electrode. The difference from Example 1 is that 4-mercaptothiophenol is used instead of 1,4-phenyldithiol. The other methods and steps are the same as in Example 1, and will not be repeated here.

[0105] Example 3

[0106] This embodiment provides a zinc negative electrode. The difference from Example 1 is that 4-mercaptobenzoic acid is used instead of 1,4-phenyldithiol. The other methods and steps are the same as in Example 1, and will not be repeated here.

[0107] Example 4

[0108] This embodiment provides a zinc negative electrode. The difference from Example 1 is that the concentration of the ethanol solution of 1,4-phenyldithiol is 0.01M. The other methods and steps are the same as in Example 1, and will not be repeated here.

[0109] Example 5

[0110] This embodiment provides a zinc negative electrode. The difference from Example 1 is that the concentration of the ethanol solution of 1,4-phenyldithiol is 0.1M. The other methods and steps are the same as in Example 1, and will not be repeated here.

[0111] Example 6

[0112] This embodiment provides a zinc negative electrode. The difference from Example 1 is that the concentration of the ethanol solution of 1,4-phenyldithiol is 1M. The other methods and steps are the same as in Example 1, and will not be repeated here.

[0113] Comparative Example 1

[0114] This comparative example provides a zinc anode, prepared by the following method:

[0115] A commercial zinc foil measuring 1.5cm × 1.5cm was polished with 1500-grit sandpaper, and then the surface was cleaned by ultrasonic cleaning with acetone and alcohol for 15 minutes in sequence to remove sandpaper residue and other impurities on the zinc foil. After rinsing three times with deionized water, it was dried under nitrogen to obtain the zinc negative electrode.

[0116] Test Example 1

[0117] Fourier transform infrared (FTIR) characterization was performed on the commercial zinc foil, zinc anode, and 1,4-phenyldithiol from Example 1. The obtained FTIR characterization images are shown below. Figure 1 As shown.

[0118] from Figure 1 As can be seen in the gray area, the self-assembled monolayer zinc foil exhibits the characteristic peak of 1,4-phenyldithiol compared to commercial zinc foil, thus proving that the zinc sheet is loaded with thiol molecules.

[0119] Test Example 2

[0120] SEM images of the commercial zinc foil and zinc anode from Example 1 after immersion in 6M KOH solution for 1 day are shown below. Figures 2-5 As shown.

[0121] Figure 2 and Figure 3 This is a SEM image of the zinc anode obtained in Example 1. Figure 4 and Figure 5 The image shows a SEM image of commercial zinc foil. It can be seen that the zinc anode obtained in Example 1 is smoother and has smaller dendrite grains after immersion than commercial zinc foil.

[0122] Test Example 3

[0123] The Tafel curves of the zinc anodes obtained in Comparative Example 1, Example 1, Example 4, and Example 5 were tested. Using Hg / HgO as the reference electrode and a platinum sheet as the counter electrode, the zinc anodes obtained in Comparative Example 1, Example 1, Example 4, and Example 5 were used as the working electrodes. The electrolyte was 6M KOH and 0.2M Zn(Ac)2. The Tafel curves were tested in a three-electrode system, and the results are as follows: Figure 6 As shown.

[0124] from Figure 6 It can be seen that the corrosion potentials all become positive. The preparation condition of soaking in 0.05M concentration for 36 hours resulted in the largest potential change, which effectively suppressed hydrogen evolution. This also demonstrates that the thiol monolayer on the zinc foil can effectively inhibit side reactions such as corrosion and hydrogen evolution.

[0125] Test Example 4

[0126] The zinc anodes obtained in Example 1 and Comparative Example 1 were subjected to scanning electron microscopy (SEM), and the resulting SEM images are shown below. Figure 7 and Figure 10 As shown.

[0127] Using Hg / HgO as the reference electrode and a zinc sheet as the counter electrode, the zinc negative electrode obtained in Example 1 and Comparative Example 1 was used as the working electrode. The electrolyte was a mixed solution of 6M KOH and 0.2M Zn(Ac)2. Under the above three-electrode system, the current was 5 mA / cm². 2 A zinc anode was obtained by constant current deposition at a constant current density for 5 minutes. The zinc anode after 5 minutes of deposition was then subjected to scanning electron microscopy (SEM), and the resulting SEM image is shown below. Figure 8 and Figure 11 As shown.

[0128] Following the deposition method and parameters described above, the zinc anodes obtained in Example 1 and Comparative Example 1 were deposited under constant current for 10 min to obtain the deposited zinc anodes. The zinc anodes after 10 min of deposition were then subjected to scanning electron microscopy (SEM), and the resulting SEM images are shown below. Figure 9 and Figure 12 As shown in the SEM images taken at the same time, the zinc anode in Example 1 exhibits a uniform deposition layer morphology, while the uneven distribution of Zn nucleation sites in Comparative Example 1 leads to a stronger tendency for Zn electrodeposition in localized areas. This becomes more pronounced as the electrodeposition time increases.

[0129] Experimental Example 1

[0130] The zinc anodes provided in Examples 1-6 and Comparative Example 1 were subjected to electrical performance tests.

[0131] 1. Preparation of zinc-air battery: The zinc negative electrode provided in Examples 1 to 6 and Comparative Example 1 is used as the negative electrode and assembled into a customized zinc-air battery mold in the following order: mold shell, tin sheet, zinc, gasket, electrolyte chamber, gasket, positive electrode sheet, and mold shell.

[0132] The zinc-air cathode preparation process is as follows: RuO2 and Pt / C (Pt content 40wt%) are mixed at a ratio of 20mg:10mg, then 150μL of Nafion (10wt%) and 4mL of ethanol are added and mixed. The mixture is then sonicated for 30min to obtain a slurry. The slurry is sprayed onto a composite catalyst support made of nickel mesh, a waterproof and breathable membrane, and carbon paper rolls using a spray gun, with a loading of 2mg / cm³. 2 .

[0133] The electrolyte is a mixed solution of 12 mL of 6 M KOH and 0.2 M Zn(Ac)2.

[0134] 2. Electrical performance testing

[0135] At 5mA / cm 2 The cycle curves under 10-minute charge-discharge cycle conditions are shown in Table 1 below.

[0136] Table 1

[0137] Failure duration / h Example 1 432 Example 2 380 Example 3 400 Example 4 360 Example 5 380 Example 6 350 Comparative Example 1 286

[0138] As shown in Table 1, the battery with the negative electrode provided in Comparative Example 1 experienced an increase in its charge / discharge voltage range after 200 hours, with a significant decrease in discharge voltage. It failed at 286 hours due to exceeding the cutoff voltage (2.5V). In contrast, the battery prepared with the negative electrode provided in the Example 1 maintained a relatively stable charge / discharge voltage plateau up to 400 hours.

[0139] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A zinc negative electrode, characterized in that, Including zinc foil and a monolayer self-assembled on the surface of zinc foil, the thiol groups in the thiol compound containing benzene ring react with zinc foil to form Zn-S bonds and exist stably on the surface of zinc foil; The monolayer is made of a thiol compound containing a benzene ring; The thiol compound containing a benzene ring is at least one of thiols, thiophenols, and thiocarboxylic acids; The thiol is 1,4-phenyldithiol; The thiophenols include at least one of benzylthiophenol, 4-hydroxybenzylthiophenol and 4-mercaptobenzylthiophenol; The thiocarboxylic acids include 4-mercaptobenzoic acid.

2. A method for preparing the zinc negative electrode according to claim 1, characterized in that, Includes the following steps: Zinc foil is immersed in a solution of a thiol compound containing benzene rings, and the thiol compound containing benzene rings self-assembles on the surface of the zinc foil to obtain the zinc negative electrode.

3. The preparation method according to claim 2, characterized in that, The concentration of the thiol compound solution containing a benzene ring is 0.01 M to 0.1 M.

4. The preparation method according to claim 2, characterized in that, The soaking time is 12 h to 48 h.

5. The preparation method according to any one of claims 2 to 4, characterized in that, It also includes pretreatment of the zinc foil before impregnation; The pretreatment includes grinding, cleaning, and drying of the zinc foil.

6. The preparation method according to claim 5, characterized in that, The polishing is performed using sandpaper with a roughness of 800-2000 grit.

7. The preparation method according to claim 5, characterized in that, The cleaning process includes organic solvent cleaning and deionized water rinsing performed in sequence. The organic solvent includes acetone and / or alcohol; The organic solvent cleaning method is ultrasonic cleaning; The ultrasonic cleaning time is 10 min to 20 min; The number of times the deionized water is rinsed is 2 to 5.

8. The preparation method according to claim 5, characterized in that, The drying process is carried out under nitrogen protection.

9. A zinc-air battery, characterized in that, Includes the positive electrode, negative electrode, and electrolyte; The negative electrode is the zinc negative electrode according to claim 1.

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