A self-assembled zincophilic hydrophobic coating for aqueous zinc-ion battery anode protection

Abstract

The application provides a self-assembled zincophilic hydrophobic coating for water-based zinc ion battery negative electrode protection, wherein the zincophilic hydrophobic coating is composed of three silane materials. The silane materials are attached to the surface of the zinc negative electrode through hydrolysis and condensation. The zincophilic hydrophobic coating effectively isolates the contact between free water in the electrolyte and the zinc electrode sheet, inhibits the hydrogen evolution reaction and inhibits the growth of zinc dendrites, improves the cycle life of the water-based zinc ion battery, ensures a good and stable charging and discharging process of the water-based zinc ion battery, maintains good deposition / detachment efficiency, and improves the cycle performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery technology, and more specifically to a self-assembled zinc-loving hydrophobic coating for the protection of the negative electrode of an aqueous zinc-ion battery. Background Technology

[0002] In recent years, due to its high theoretical specific capacity (820 mAh g), 1 Low redox potential With its low voltage (0.76 V vs SHE) and abundant zinc resources, aqueous zinc-ion batteries (AZIBs) have become a very promising candidate system for large-scale energy storage. Furthermore, the unique advantages of aqueous electrolytes, including their safety, non-toxicity, environmental friendliness, low cost, and excellent ionic conductivity, contribute to further enhancing the large-scale application potential of this system. However, zinc anodes are susceptible to battery failure, which can be attributed to dendrite growth and complex interfacial side reactions. These factors have become major obstacles to the practical application of zinc anodes.

[0003] Unfortunately, the application of zinc anodes is hindered by dendrite growth and corrosive electrolytes. Dendrite formation is typically caused by a non-uniform local environment (Zn). 2+ Electrochemical corrosion, caused by factors such as concentration, electric field, and surface defects, induces internal short circuits. It originates from the thermodynamic instability of zinc in the electrolyte, producing insulating byproducts and consuming a limited amount of electrolyte, leading to severe deterioration of electrochemical performance.

[0004] Since two key issues with zinc anodes are closely related to the electrode / electrolyte interface, modulating this interface is crucial. To date, numerous methods have been successfully developed to address these problems, such as constructing 3D current collectors, optimizing electrolyte formulations, and pre-coating artificial layers onto Zn. Among these methods, the construction of artificial interface protective layers is considered a promising approach to interface modulation, aiming to mitigate dendrite growth and suppress side reactions. Typically, the optimal interface layer should meet the following design criteria: 1) zinc affinity, which helps guide uniform Zn nucleation and growth; 2) hydrophobicity, which effectively suppresses electrolyte erosion and hydrogen evolution reactions; and 3) fast ion flux, which benefits the rapid reaction kinetics of the Zn anode.

[0005] Therefore, there is an urgent need to develop a low-cost, easy-to-synthesize, and mass-producible coating material for protecting the negative electrode of aqueous zinc-ion batteries. Summary of the Invention

[0006] This invention provides a self-assembled zinc-loving hydrophobic coating for the protection of the negative electrode in aqueous zinc-ion batteries. The hydrophobic coating effectively isolates free water in the electrolyte from contact with the zinc electrode sheet, reducing electrolyte corrosion of the zinc negative electrode, inhibiting dendrite growth and hydrogen evolution reaction, and promoting Zn production.2+ Uniform deposition improves the cycle life of aqueous zinc-ion batteries.

[0007] The present invention provides the following solution to the above-mentioned technical problems: a zinc-ion battery negative electrode coated with a zinc-philic and hydrophobic coating, the preparation method of which includes the following steps: 1) The surface of the zinc sheet is polished and cleaned to obtain the zinc negative electrode sheet; 2) Preparation of coating solution: Add the organic nitrogen-containing silane to a mixed solvent composed of deionized water and organic solvent, stir evenly to obtain the pre-hydrolyzed coating solution; 3) Coating and film formation: The coating liquid is applied to the surface of the treated zinc metal substrate, causing the organosilane to undergo hydrolysis and condensation reaction, forming a dense nitrogen-containing organosilane coating on the zinc metal surface.

[0008] 4) The nitrogen-containing organosilane coating is immersed in a mixed solution of epoxy silane and fluorine-containing silane, and then reacted and dried to form a dense hydrophobic organosilane coating on the zinc metal surface.

[0009] Further optimized, the organic nitrogen-containing silane is at least one of (3-aminopropyl)trimethoxysilane and (3-aminopropyl)triethoxysilane.

[0010] Further optimized, the concentration of silane in the mixed solvent is 10~30 mmol L. 1 The organic solvent is at least one of ethanol and isopropanol.

[0011] Further optimized, the application method is spin coating, dip coating, spray coating, or blade coating.

[0012] Further optimized, the epoxy silane is 3-glycidyloxypropyltrimethoxysilane.

[0013] Further optimized, the fluorinated silane is triethoxy-1H,1H,2H,2H-tetrafluoron-octylsilane.

[0014] Further optimized, the ratio of epoxy silane to fluorinated silane in the mixed solution is 1~2:1.

[0015] Further optimized, the drying process involves drying at 60°C for 30 min to 2 h.

[0016] This invention provides an interface coating for the metallic zinc anode of an aqueous zinc-ion battery and its preparation method. The coating is composed of a silane material, which exhibits good zinc affinity and hydrophobicity, effectively preventing corrosion of the zinc foil by the aqueous electrolyte and promoting Zn production. 2+Uniform deposition on the electrode surface suppresses zinc dendrite growth and related side reactions. This significantly improves the battery's cycle life and deposition / stripping efficiency, while also ensuring the stability and safety of the charge-discharge process, exhibiting excellent performance at different current densities. The preparation method of this invention is simple, environmentally friendly, low-cost, and easy to operate, possessing strong commercial application potential.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 The symmetrical cell assembled in Example 1 was at 10 mAcm 2 Current density and 2 mAhcm 2 Constant current charge-discharge data graph under capacity; Figure 2 The symmetrical cell assembled in Example 2 was at 10 mAcm 2 Current density and 2 mAhcm 2 Constant current charge-discharge data graph under capacity; Figure 3 The symmetrical cell assembled in Example 3 was tested at 10 mAcm. 2 Current density and 2 mAhcm 2 Constant current charge-discharge data graph under capacity; Figure 4 Symmetric cells assembled for comparative purposes at 10 mAcm 2 Current density and 2 mAhcm 2 Constant current charge-discharge data graph under capacity; Detailed Implementation The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0019] Example 1 This embodiment provides a zinc-ion battery anode modified with a zinc-loving hydrophobic coating, and its preparation steps are as follows: Step 1: Polish the zinc foil with sandpaper of grades 800C, 1000C, and 2000C in sequence, rinse it with 99.9% ethanol, and wipe it dry with lint-free paper to obtain the zinc negative electrode sheet.

[0020] Step 2: Add 22 mmol L 1 (3-Aminopropyl)trimethoxysilane was dissolved in anhydrous ethanol, and the pH of the solution was maintained at 4-5 by adding glacial acetic acid. Hydrolysis was carried out by stirring at 50°C for 48 hours, and then polished zinc foil was immersed in the solution for 30 minutes to ensure sufficient amine groups on the surface. A zinc anode coated with (3-aminopropyl)trimethoxysilane was obtained.

[0021] Step 3: Add 20 mmol L 1 3-glycidyloxypropyltrimethoxysilane and 10 mmol L 1 Triethoxy-1H,1H,2H,2H-tridecylfluoro-n-octylsilane was added to anhydrous ethanol, and then the pH of the solution was maintained at 8-9 by adding ammonia. Hydrolysis was carried out by stirring at 50°C for 48 hours.

[0022] Step 4: The resulting zinc anode coated with (3-aminopropyl)trimethoxysilane was then immersed in the above solution for 30 min, and then the zinc sheet was air-dried at 60°C for 1 hour to promote the amine-epoxy ring-opening reaction. A zinc-loving and hydrophobic zinc anode was obtained.

[0023] Example 2 This embodiment provides a zinc-ion battery anode modified with a zinc-loving hydrophobic coating, and its preparation steps are as follows: Step 1: Polish the zinc foil with sandpaper of grades 800C, 1000C, and 2000C in sequence, rinse it with 99.9% ethanol, and wipe it dry with lint-free paper to obtain the zinc negative electrode sheet.

[0024] Step 2: Add 22 mmol L 1 (3-Aminopropyl)trimethoxysilane was dissolved in anhydrous ethanol, and the pH of the solution was maintained at 4-5 by adding glacial acetic acid. Hydrolysis was carried out by stirring at 50°C for 48 hours, and then polished zinc foil was immersed in the solution for 15 minutes to ensure sufficient amine groups on the surface. A zinc anode coated with (3-aminopropyl)trimethoxysilane was obtained.

[0025] Step 3: Add 20 mmol L 13-glycidyloxypropyltrimethoxysilane and 10 mmol L 1 Triethoxy-1H,1H,2H,2H-tridecylfluoro-n-octylsilane was added to anhydrous ethanol, and then the pH of the solution was maintained at 8-9 by adding ammonia. Hydrolysis was carried out by stirring at 50°C for 48 hours.

[0026] Step 4: The resulting zinc anode coated with (3-aminopropyl)trimethoxysilane was then immersed in the above solution for 15 min, and then the zinc sheet was air-dried at 60°C for 1 hour to promote the amine-epoxy ring-opening reaction. A zinc-loving and hydrophobic zinc anode was obtained.

[0027] Example 3 This embodiment provides a zinc-ion battery anode modified with a zinc-loving hydrophobic coating, and its preparation steps are as follows: 1) Polish the zinc foil with sandpaper of grades 800C, 1000C, and 2000C in sequence, rinse it with 99.9% ethanol, and wipe it dry with lint-free paper to obtain the zinc negative electrode sheet.

[0028] 2) Add 22 mmol L 1 (3-Aminopropyl)trimethoxysilane was dissolved in anhydrous ethanol, and the pH of the solution was maintained at 4-5 by adding glacial acetic acid. Hydrolysis was carried out by stirring at 50°C for 48 hours, and then polished zinc foil was immersed in the solution for 1 hour to ensure sufficient amine groups on the surface. A zinc anode coated with (3-aminopropyl)trimethoxysilane was obtained.

[0029] 3) Add 20 mmol L 1 3-glycidyloxypropyltrimethoxysilane and 10 mmol L 1 Triethoxy-1H,1H,2H,2H-tridecylfluoro-n-octylsilane was added to anhydrous ethanol, and then the pH of the solution was maintained at 8-9 by adding ammonia. Hydrolysis was carried out by stirring at 50°C for 48 hours.

[0030] 4) The resulting zinc anode coated with (3-aminopropyl)trimethoxysilane was then immersed in the above solution for 1 hour, and then the zinc sheet was dried at 60°C for 1 hour to promote the amine-epoxy ring-opening reaction. A zinc-loving and hydrophobic zinc anode was obtained.

[0031] Comparative Example 1 This comparative example uses polished, untreated zinc foil as the negative electrode of the battery.

[0032] Cycle performance tests were conducted on the batteries assembled in the above embodiments and comparative examples: At 10 mA cm 2 Current density and 2 mAh cm 2 As shown in the figure, under a fixed capacity, the zinc symmetric cell coated with the zinc-loving hydrophobic coating prepared in Example 1 exhibits low voltage polarization and stable operation for more than 2000 h, while the uncoated zinc symmetric cell can only operate for 46 h under the same conditions.

Claims

1. A self-assembled zinc-philic hydrophobic coating for the negative electrode protection of aqueous zinc-ion batteries, characterized in that, Includes the following steps: 1) The surface of the zinc sheet is polished and cleaned to obtain the zinc negative electrode sheet; 2) Preparation of coating solution: Add the organic nitrogen-containing silane to a mixed solvent composed of deionized water and organic solvent, stir evenly to obtain the pre-hydrolyzed coating solution; 3) Coating and film formation: The coating liquid is applied to the surface of the treated zinc metal substrate, causing the organosilane to undergo hydrolysis and condensation reaction, forming a dense nitrogen-containing organosilane coating on the zinc metal surface. 4) The nitrogen-containing organosilane coating is immersed in a mixed solution of epoxy silane and fluorine-containing silane, and then reacted and dried to form a dense hydrophobic organosilane coating on the zinc metal surface.

2. The self-assembled zinc-philic hydrophobic coating for the negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 2), the organic nitrogen-containing silane is at least one of (3-aminopropyl)trimethoxysilane and (3-aminopropyl)triethoxysilane.

3. The self-assembled zinc-philic hydrophobic coating for the negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 2), the concentration of silane in the mixed solvent is 10-30 mmol / L. 1 The organic solvent is at least one of ethanol and isopropanol.

4. The self-assembled zinc-philic hydrophobic coating for negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 3), the application method is spin coating, dip coating, spray coating, or scraping coating.

5. The self-assembled zinc-philic hydrophobic coating for the negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 3), the epoxy silane is 3-glycidyloxypropyltrimethoxysilane.

6. The self-assembled zinc-philic hydrophobic coating for negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 3), the fluorinated silane is triethoxy-1H,1H,2H,2H-tetrafluoron-octylsilane.

7. The self-assembled zinc-philic hydrophobic coating for the negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 4), the ratio of epoxy silane to fluorinated silane in the mixed solution is 1~2:

1.

8. The self-assembled zinc-philic hydrophobic coating for negative electrode protection of aqueous zinc-ion batteries according to claim 1, characterized in that, In step 4), the drying process involves drying at 60°C for 30 min to 2 h.

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