A method for protecting the zinc anode of an aqueous zinc-ion battery based on an organic eutectic interface layer

Abstract

This invention discloses a method for protecting the zinc anode of an aqueous zinc-ion battery based on an organic eutectic interface layer, belonging to the field of electrochemical energy storage technology. This invention effectively controls the Zn content by constructing an artificial interface layer (MA-IPA@Zn) composed of organic eutectic materials on the surface of the zinc anode. 2+ Deposition behavior and suppression of interfacial side reactions. The hydrogen bond network in the organic eutectic can trap active water molecules, while simultaneously reacting with Zn. 2+ This synergistic effect achieves uniform deposition and suppresses dendrite growth. This method significantly improves the cycle stability and coulombic efficiency of aqueous zinc-ion batteries, and has advantages such as simple preparation, good interfacial stability, and broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage technology, and more specifically relates to a method for protecting the zinc anode of an aqueous zinc-ion battery based on an organic eutectic interface layer. Background Technology

[0002] With the rapid development of renewable energy, energy storage systems that are highly safe, low-cost, and environmentally friendly have attracted widespread attention. Aqueous zinc-ion batteries, due to their advantages such as high safety, abundant resources, low cost, and environmental friendliness, are considered to be an energy storage system with great application potential.

[0003] However, aqueous zinc-ion batteries still face a series of key problems during cycling, such as zinc dendrite growth, severe side reactions, and poor electrode interface stability. Specifically, the zinc anode is prone to uneven deposition during charge and discharge, leading to zinc dendrite formation and subsequently causing short circuits or capacity decay. Furthermore, water molecules in the electrolyte can trigger hydrogen evolution reaction (HER) and corrosion, accelerating electrode failure.

[0004] To alleviate these problems, researchers have proposed controlling the interface of zinc anodes by constructing artificial interface layers. For example, inorganic materials, organic polymers, or composite materials can be used as protective layers. However, existing interface materials often suffer from limited ion transport capabilities, insufficient interface stability, or complex fabrication processes.

[0005] Organic eutectic materials are supramolecular crystal structures formed through weak intermolecular interactions (such as hydrogen bonds and π-π interactions), possessing advantages such as strong structural designability and excellent interface controllability. Therefore, applying organic eutectic materials to zinc anode interface protection holds promise for effectively controlling water molecules in the electrolyte and optimizing Zn. 2+ The deposition behavior significantly improves the performance of aqueous zinc-ion batteries.

[0006] Based on this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for protecting the zinc anode of an aqueous zinc-ion battery based on an organic eutectic interface layer, thereby solving the problems existing in the prior art. This invention achieves protection of Zn by constructing a stable organic eutectic protective layer on the surface of the zinc anode. 2+ Effective regulation of deposition behavior and interfacial side reactions can improve the cycle stability of aqueous zinc-ion batteries.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] One of the technical solutions of this invention is to provide a method for protecting the zinc anode of an aqueous zinc-ion battery based on an organic eutectic interface layer, comprising the following steps:

[0010] S1. Pre-treat the zinc substrate to remove the surface oxide layer and improve surface smoothness;

[0011] S2. Prepare an organic eutectic material, wherein the organic eutectic material is formed by hydrogen bonding between melamine and isophthalic acid;

[0012] S3. Disperse the organic eutectic material obtained in step S2 in an emulsion system to form a uniform slurry, coat it on the zinc substrate surface after pretreatment in step S1, and dry it to form an interface modification coating to obtain the MA-IPA@Zn interface-modified zinc anode.

[0013] Preferably, the zinc substrate in step S1 is zinc foil with a purity of 99.999% and a thickness of 0.02~0.1mm; the pretreatment includes polishing with 400#, 1500# and 3000# sandpaper in stages, followed by cleaning with water and anhydrous ethanol and drying.

[0014] Preferably, in step S2, the molar ratio of melamine to isophthalic acid is 0.5~1.5:1. The solution is dissolved at 150°C using a hydrothermal method to form a supersaturated solution, and then subjected to gradient cooling crystallization at a rate of 20~40°C / h to obtain MA-IPA organic eutectic, which is the organic eutectic material.

[0015] Preferably, the slurry in step S3 includes water, sodium carboxymethyl cellulose, styrene-butadiene rubber, and MA-IPA organic eutectic, wherein the ratio of water, sodium carboxymethyl cellulose, styrene-butadiene rubber, and MA-IPA organic eutectic is 4 mL: 50 mg: 50~100 μL: 400 mg.

[0016] Preferably, in step S3, a blade coating method is used for coating, the coating thickness is 200 μm, the drying temperature is 60°C, and the drying time is 12 h.

[0017] The second technical solution of the present invention provides an MA-IPA@Zn interface-modified zinc anode prepared by the above method.

[0018] The third technical solution of the present invention provides the application of the above-mentioned MA-IPA@Zn interface-modified zinc anode in an aqueous zinc-ion battery.

[0019] The fourth technical solution of the present invention provides an aqueous zinc-ion battery, wherein the zinc anode is modified with the above-mentioned MA-IPA@Zn interface as a zinc anode.

[0020] Preferably, the aqueous zinc-ion battery includes a zinc symmetric cell, a Zn / / Cu half-cell, or a full cell assembled with an NVO positive electrode.

[0021] The technical principle of this invention is as follows:

[0022] This invention achieves effective regulation of zinc deposition behavior and suppression of interfacial side reactions by constructing an organic eutectic interface modification layer (MA-IPA@Zn) formed by the self-assembly of melamine (MA) and isophthalic acid (IPA) through hydrogen bonding on the surface of the zinc anode.

[0023] Specifically, the MA-IPA organic eutectic material possesses a highly ordered hydrogen bond network structure. This hydrogen bond network can effectively capture active water molecules in the electrolyte through hydrogen bond interactions, reducing the activity of free water on the zinc anode surface, thereby significantly inhibiting the hydrogen evolution reaction (HER) and zinc corrosion. Simultaneously, the abundant polar functional groups (such as amino and carboxyl groups) in this organic eutectic layer can interact with Zn... 2+ Coordination is formed, guiding Zn 2+ Uniform distribution and orderly deposition on the electrode surface avoid dendrite growth caused by local charge accumulation.

[0024] Furthermore, this organic eutectic interface layer, as an artificial solid electrolyte interface (SEI), possesses excellent ion conductivity and mechanical flexibility. It can form a physical barrier on the zinc anode surface, isolating zinc metal from direct contact with the electrolyte and further suppressing side reactions. During charge and discharge, this interface layer can maintain structural stability and adapt to the volume changes of the zinc anode, thereby achieving long-cycle stable zinc deposition / stripping behavior.

[0025] In summary, this invention achieves comprehensive optimization of zinc deposition kinetics, interfacial side reactions, and structural stability through the synergistic regulation of the organic eutectic interface layer, significantly improving the cycle life and coulombic efficiency of aqueous zinc-ion batteries.

[0026] The present invention discloses the following technical effects:

[0027] This invention modifies Zn by constructing an organic eutectic interface modification layer on the surface of a zinc anode and utilizing the organic eutectic structure. 2+ The deposition behavior of the organic eutectic material allows zinc ions to be uniformly deposited on the electrode surface, effectively suppressing the formation of zinc dendrites. Simultaneously, the hydrogen bond network in the eutectic structure can capture and shield active water molecules in the electrolyte, reducing hydrogen evolution and corrosion reactions, and forming a stable artificial SEI interface layer on the zinc surface, improving the stability of the zinc anode interface. Furthermore, compared with traditional alloying or inorganic material modification methods, the organic eutectic material used in this invention has advantages such as good flexibility, low raw material cost, and simple preparation process, making it more suitable for large-scale production and practical applications. Attached Figure Description

[0028] Figure 1 A schematic diagram of the crystal structure of MA-IPA organic eutectic;

[0029] Figure 2 Morphology images of the MA-IPA@Zn interface-modified zinc electrode, including optical microscope images and scanning electron microscope images;

[0030] Figure 3 The image shows a comparison of the surface morphology of the bare zinc electrode and the MA-IPA@Zn electrode after 50 cycles using scanning electron microscopy.

[0031] Figure 4 The MA-IPA@Zn prepared in Example 1 was used as the negative electrode of an aqueous zinc-ion battery at a current density of 1 mA / cm². 2 Surface capacity is 1mAh / cm 2 Comparison of cycle performance of symmetric batteries constructed under the specified conditions;

[0032] Figure 5 The MA-IPA@Zn prepared in Example 1 was used as the negative electrode of an aqueous zinc-ion battery. A Zn / / Cu half-cell assembled with Cu foil as the positive electrode was used at a current density of 0.5 mA / cm². 2 Surface capacity is 1mAh / cm 2 Comparison of Coulomb efficiency under the given conditions;

[0033] Figure 6 The graph shows the charge-discharge performance of a full cell assembled with an NVO positive electrode using MA-IPA@Zn as the negative electrode material prepared in Example 1 at a current density of 4 A / g. Detailed Implementation

[0034] This invention provides a method for protecting the zinc anode of an aqueous zinc-ion battery based on an organic eutectic interface layer, comprising the following steps:

[0035] Step 1: Grind the zinc sheet sequentially using 400#, 1500#, and 3000# sandpaper to remove the surface oxide layer and improve surface smoothness. Then, ultrasonically clean the zinc sheet in deionized water and anhydrous ethanol to remove surface impurities. Finally, dry it with nitrogen gas to obtain a pretreated zinc substrate.

[0036] Step 2: Weigh melamine (MA) and isophthalic acid (IPA) at a molar ratio of 0.5~1.5:1, add them to deionized water, and dissolve them under hydrothermal conditions at 150℃ to form a homogeneous supersaturated system. Then, subject the solution to gradient cooling crystallization at a cooling rate of 20~40℃ / h. During the cooling process, MA molecules and IPA molecules form a stable supramolecular eutectic structure through hydrogen bonding. After crystallization, filter and dry the resulting crystals to obtain the MA-IPA organic eutectic material.

[0037] Step 3: Disperse the MA-IPA organic eutectic obtained in Step 2 in an emulsion system composed of sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and deionized water, and stir thoroughly to form a homogeneous slurry. The amounts of each component in the emulsion system are as follows: 4 mL of deionized water, 50 mg of CMC, 400 mg of MA-IPA eutectic, and 50-100 μL of SBR.

[0038] Step 4: Subsequently, the slurry obtained in Step 3 is uniformly coated onto the pretreated zinc substrate obtained in Step 1 using a doctor blade coating method. The thickness of the doctor blade used is 200 μm. After coating, the electrode is placed in an oven for drying to allow the moisture to evaporate completely and form a stable interface modification coating, thereby obtaining the MA-IPA@Zn interface-modified zinc anode.

[0039] The MA-IPA@Zn interface-modified zinc anode prepared above was applied to a full-cell system assembled with an NVO cathode. The battery consisted of an NVO cathode, a 2M ZnSO4 aqueous electrolyte, a Whatman GF / D glass fiber membrane, and the MA-IPA@Zn anode. Furthermore, the MA-IPA@Zn interface-modified zinc anode can also be used to construct zinc symmetric cells and Zn / / Cu half-cells, where the MA-IPA@Zn electrode simultaneously serves as both the positive and negative electrodes of the symmetric cell.

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0042] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0043] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0044] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0045] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0046] Example 1

[0047] This embodiment provides a method for preparing a modified zinc metal anode with an MA-IPA@Zn coating, comprising the following steps:

[0048] S1, Zinc foil pretreatment

[0049] The zinc foil was successively polished using 400#, 1500#, and 3000# sandpaper to remove the surface oxide layer and improve surface smoothness. The polished zinc foil was then ultrasonically cleaned in deionized water and anhydrous ethanol to remove residual impurities. Finally, it was dried with nitrogen gas to obtain the pretreated zinc substrate.

[0050] Preparation of S2 and MA-IPA organic eutectic

[0051] 31 mg of melamine (MA) and 42 mg of isophthalic acid (IPA) were weighed and added to 7 mL of deionized water. The solution was heated at 150 °C for 4 h under hydrothermal conditions to ensure complete dissolution and the formation of a homogeneous supersaturated solution. The solution was then subjected to gradient cooling crystallization at a rate of 20 °C / h. During the cooling process, MA and IPA molecules formed a stable supramolecular eutectic structure through hydrogen bonding. After crystallization, the resulting crystals were filtered and dried to obtain the MA-IPA organic eutectic material with a eutectic yield of approximately 70%.

[0052] Preparation of S3 and MA-IPA@Zn negative electrodes

[0053] The obtained MA-IPA organic eutectic was dispersed in an emulsion system composed of sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and deionized water, and thoroughly stirred to form a homogeneous slurry. The amounts of each component were: 4 mL of deionized water, 50 mg of CMC, 400 mg of MA-IPA eutectic, and 50 μL of SBR. The slurry was then uniformly coated onto the pretreated zinc substrate surface using a doctor blade coating method, with a blade thickness of 200 μm. After coating, the electrode was placed in a vacuum drying oven at 60 °C for approximately 12 h to allow the solvent to completely evaporate and form a stable interface modification coating, thus obtaining the MA-IPA@Zn interface-modified zinc anode.

[0054] The obtained MA-IPA crystal was subjected to single-crystal XRD analysis, and the results were as follows: Figure 1 The crystal structure results are shown; the MA-IPA@Zn electrode was characterized by scanning electron microscopy (SEM) to obtain the following results: Figure 2 The electrode surface morphology results are shown.

[0055] Example 2

[0056] This embodiment describes the assembly and application of the MA-IPA@Zn interface-modified zinc anode prepared in Example 1 into a battery, including assembly methods for symmetrical cells, half-cells, and full cells. The specific steps are as follows.

[0057] Assembly of S1 symmetric cell

[0058] The MA-IPA@Zn electrodes prepared in Example 1 were used as the positive and negative electrodes of the coin cell, respectively. A glass fiber membrane (GF / D) was used as the separator, and a 2 mol / L ZnSO4 aqueous solution was used as the electrolyte. The cells were assembled into a CR2032 type coin cell under normal environmental conditions, denoted as MA-IPA@Zn / / MA-IPA@Zn symmetric cell.

[0059] Assembly of S2 half-cell

[0060] The MA-IPA@Zn electrode prepared in Example 1 was used as the negative electrode of the button cell, copper foil was used as the positive electrode, glass fiber membrane (GF / D) was used as the separator, and a 2 mol / L ZnSO4 aqueous solution was used as the electrolyte. The CR2032 type button cell was assembled under normal environmental conditions and denoted as MA-IPA@Zn / / Cu half cell.

[0061] S3 full battery assembly

[0062] First, NVO cathode material was prepared. 1.75 g of NaCl and 1 g of V₂O₅ were weighed and added to 15 mL of deionized water, and reacted for 36 h under magnetic stirring. After the reaction was complete, the resulting product was washed multiple times with deionized water and separated by filtration. The product was then dried to obtain NVO material. The obtained NVO, conductive carbon black, and polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 7:2:1, thoroughly ground in an agate mortar, and then an appropriate amount of N-methylpyrrolidone (NMP) was added as a solvent. The mixture was then thoroughly mixed to obtain an electrode slurry. This slurry was uniformly coated onto the surface of a titanium foil current collector and dried in a vacuum drying oven for 12 h to obtain the NVO cathode electrode sheet. Subsequently, the MA-IPA@Zn electrode prepared in Example 1 was used as the negative electrode, the NVO electrode as the positive electrode, a glass fiber membrane (GF / D) was used as the separator, and a 2 mol / L ZnSO4 aqueous solution was used as the electrolyte. Under normal environmental conditions, a CR2032 button cell was assembled, which was denoted as the MA-IPA@Zn / / NVO full cell.

[0063] Example 3

[0064] The MA-IPA@Zn / / MA-IPA@Zn symmetrical cell assembled in Example 2 was subjected to a current density of 1 mA / cm². 2 Surface capacity is 1mAh / cm 2 After 50 cycles under the specified conditions, the battery was disassembled and the negative electrode was removed. Scanning electron microscopy (SEM) was then performed on it, yielding the following results: Figure 3 The electrode surface morphology results are shown.

[0065] Meanwhile, the MA-IPA@Zn / / MA-IPA@Zn symmetrical cell assembled in Example 2 was subjected to a current density of 1 mA / cm². 2 Surface capacity is 1mAh / cm 2 Long-term cycling tests were conducted under specific conditions to evaluate the cycling stability of the MA-IPA@Zn electrode, and the results were as follows: Figure 4 The cycle performance curves are shown.

[0066] The MA-IPA@Zn / / Cu half-cell assembled in Example 2 was tested at a current density of 0.5 mA / cm². 2 Surface capacity is 1mAh / cm 2 Cyclic tests were conducted under specific conditions, and the reversibility of zinc plating / stripping was evaluated by analyzing its coulombic efficiency. The test results are as follows: Figure 5 As shown.

[0067] The MA-IPA@Zn / / NVO full cell assembled in Example 2 was subjected to cycle testing at a current density of 2 A / g. The cycle stability of the cell was evaluated by analyzing its capacity retention rate. The test results are as follows: Figure 6 As shown.

[0068] Figure 1 The crystal morphology and structure of the MA-IPA organic eutectic are shown. The results demonstrate the successful preparation of MA-IPA eutectic crystals with a specific crystal structure, proving the successful preparation of MA-IPA organic eutectic materials.

[0069] Figure 2 The macroscopic and microscopic morphology characterization results of the MA-IPA@Zn electrode are shown. It can be observed that the MA-IPA coating is uniformly covered on the zinc surface, indicating that the MA-IPA interface modification layer was successfully constructed on the zinc substrate.

[0070] Figure 3 Scanning electron microscopy (SEM) results of the zinc anode surface morphology after 50 cycles of a zinc / / zinc symmetric cell are shown. Compared with the bare zinc electrode, the MA-IPA@Zn electrode surface is smoother and denser, indicating that the MA-IPA interface modification layer can effectively regulate zinc deposition behavior, thereby inhibiting zinc dendrite growth.

[0071] Figure 4 This demonstrates a zinc / / zinc symmetric cell at a current density of 1 mA / cm². 2 Surface capacity is 1mAh / cm 2 Cyclic performance curves under the specified conditions are shown. The MA-IPA@Zn / / MA-IPA@Zn symmetric cell can cycle stably for 2500 hours, while the bare zinc symmetric cell short-circuits after approximately 300 hours, indicating that the MA-IPA interface modification layer can significantly improve the cycle stability of the zinc anode.

[0072] Figure 5 The electroplating / stripping performance of the MA-IPA@Zn electrode in a Zn / / Cu half-cell is shown, with a coulombic efficiency of 99.6%, indicating that the interface modification layer can effectively improve the reversibility of the zinc deposition and stripping process.

[0073] Figure 6 The electrochemical performance of a full cell assembled with MA-IPA@Zn as the anode material and NVO as the cathode is shown. After 2000 cycles at a current density of 4 A / g, it still retains 77.87% of its capacity, further demonstrating the excellent structural and electrochemical stability of the MA-IPA@Zn interface-modified zinc anode.

[0074] The results in summary demonstrate that the MA-IPA organic eutectic interface modification layer constructed in this invention can effectively regulate Zn. 2+ The deposition behavior inhibits zinc dendrite growth and improves the interfacial stability and cycle performance of the zinc anode.

[0075] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for protecting zinc anodes in aqueous zinc-ion batteries based on organic co-crystal interfacial layers, characterized in that, The method comprises the following steps: S1, pretreating a zinc substrate to remove the surface oxide layer and improve the surface flatness; S2, preparing an organic co-crystal material formed by melamine and isophthalic acid through hydrogen bonding; S3, dispersing the organic co-crystal material prepared in step S2 in an emulsion system to form a uniform slurry, coating the surface of the zinc substrate pretreated in step S1, and drying to form an interface modification coating layer, thereby obtaining a MA-IPA@Zn interface modified zinc negative electrode.

2. The method of claim 1, wherein, The zinc substrate in step S1 is a zinc foil with a purity of 99.999% and a thickness of 0.02-0.1 mm; the pretreatment includes step-by-step polishing with 400#, 1500# and 3000# sandpaper, and then cleaning with water and anhydrous ethanol and drying.

3. The method of claim 1, wherein, In step S2, the molar ratio of melamine to isophthalic acid is 0.5-1.5:1, a supersaturated solution is formed by hydrothermal method at 150℃, and then gradient cooling crystallization is carried out at a rate of 20-40℃ / h to obtain MA-IPA organic co-crystal, which is the organic co-crystal material.

4. The method of claim 1, wherein, In step S3, the slurry comprises water, sodium carboxymethyl cellulose, butadiene-styrene rubber and MA-IPA organic co-crystal, wherein the amount ratio of water, sodium carboxymethyl cellulose, butadiene-styrene rubber and MA-IPA organic co-crystal is 4mL:50mg:50-100μL:400mg.

5. The method of claim 1, wherein, In step S3, the coating is carried out by doctor blade coating method, the coating thickness is 200μm, the drying temperature is 60℃, and the drying time is 12h.

6. The MA-IPA@Zn interface modified zinc negative electrode prepared by the method of any one of claims 1-5.

7. The application of the MA-IPA@Zn interface modified zinc negative electrode of claim 6 in a water-based zinc ion battery.

8. An aqueous zinc-ion battery, characterized in that, The MA-IPA@Zn interface modified zinc negative electrode of claim 6 is used as a zinc anode.

9. The aqueous zinc-ion battery of claim 8, wherein, The water-based zinc ion battery comprises a zinc symmetric battery, a Zn / / Cu half-cell or a full cell assembled with an NVO positive electrode. The water-based zinc ion battery comprises a zinc symmetric battery, a Zn / / Cu half-cell or a full cell assembled with an NVO positive electrode.

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