A method for preparing a negative electrode current collector for zinc-nickel batteries

Abstract

This application relates to the field of zinc-based battery technology and discloses a method for preparing a negative electrode current collector for zinc-nickel batteries. The negative electrode current collector includes a three-dimensional porous copper substrate and a tin-antimony functional layer formed on the surface of the substrate. The preparation method involves immersing the three-dimensional porous copper substrate in a functional deep eutectic solvent and performing a low-temperature in-situ chemical conversion reaction at a preset temperature of 80–120°C. The functional deep eutectic solvent is prepared from choline chloride, urea, anhydrous stannous chloride as a tin source, anhydrous antimony trichloride as an antimony source, and imidazole as a reaction regulator. This invention utilizes the copper substrate as a reducing agent to generate a tin-antimony functional layer that is firmly bonded to the substrate in situ. This method is a one-pot operation with a simple process and no wastewater generation. The obtained current collector can effectively inhibit zinc dendrite growth, improving the cycle life and safety of the battery.

Description

Technical Field

[0001] This invention relates to the field of zinc-based battery technology, specifically to a method for preparing a negative electrode current collector for a zinc-nickel battery. Background Technology

[0002] Zinc-nickel batteries have shown great promise in the energy storage field due to their high energy density, high safety, and low cost. However, zinc anodes commonly suffer from zinc dendrite growth and severe side reactions during cyclic charging and discharging, which can lead to internal short circuits and rapid capacity decay, greatly limiting their practical application and commercialization.

[0003] To address this challenge, one of the research focuses in this field is to construct interfaces with high zinc affinity by surface functionalizing the negative electrode current collector (typically copper foil or copper foam) to guide uniform zinc ion deposition and thus inhibit zinc dendrite growth. Currently, the mainstream technology for achieving this surface modification is the traditional aqueous electroplating method.

[0004] However, traditional water-based electroplating processes have revealed numerous shortcomings in practical applications. The process is typically lengthy and complex, and inevitably generates large amounts of wastewater containing heavy metal ions, leading to significant environmental treatment pressure and costs. More importantly, the adhesion between the electroplated layer and the substrate is often limited. During repeated charge-discharge cycles of the battery, the plating layer is prone to cracking or even peeling due to stress changes, resulting in functional failure. Furthermore, for current collectors with three-dimensional porous structures, electroplating processes struggle to achieve uniform and dense surface coverage, affecting the overall consistency of the current collector's performance.

[0005] Therefore, this invention proposes a method for preparing a negative electrode current collector for zinc-nickel batteries to overcome the shortcomings of existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for preparing a zinc-nickel battery negative electrode current collector, which solves the problems of traditional aqueous electroplating, such as complex process flow, numerous steps, high wastewater treatment costs, poor adhesion between functional layer and substrate, and difficulty in forming a uniform and dense coating on a three-dimensional complex structure.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a zinc-nickel battery negative electrode current collector, which adopts the following technical solution:

[0009] A zinc-nickel battery negative electrode current collector includes a three-dimensional porous copper substrate and a tin-antimony functional layer formed on the surface of the three-dimensional porous copper substrate. The tin-antimony functional layer is prepared by low-temperature in-situ chemical transformation of the three-dimensional porous copper substrate in a functional deep eutectic solvent containing a tin source, an antimony source, and imidazole.

[0010] By employing the above-mentioned technical solution, a tin-antimony functional layer is directly generated on the surface of a three-dimensional porous copper substrate. The innovative principle of this method lies in the fact that, during the reaction process, the copper substrate itself not only acts as a carrier for the functional layer but also as a reactant and an in-situ reducing agent. This makes the formation of the tin-antimony functional layer a process of "growing" from the substrate surface, rather than a simple physical deposition. Therefore, a metallurgical bond or a strong chemical bond is formed at the interface between the functional layer and the copper substrate, achieving an interfacial bonding force far exceeding that of traditional electroplating processes. This superior bonding force ensures the structural stability of the current collector during repeated charge-discharge cycles of the battery, effectively preventing the functional layer from peeling off, thereby guaranteeing the long-term cycle performance and rate performance of the battery.

[0011] Preferably, the three-dimensional porous copper substrate is a porous body with a three-dimensional mesh structure prepared by non-subtractive processing of copper foil.

[0012] Preferably, in the tin-antimony functional layer, the atomic ratio of tin to antimony is (1.5-2.5):1. By adopting this technical solution, tin-antimony alloys or composites with this specific atomic ratio have been proven to have excellent zinc affinity and moderate conductivity, which can effectively guide the deposition behavior of zinc ions, reduce the nucleation overpotential of zinc, and promote smooth and dense deposition of zinc, thereby inhibiting the formation of zinc dendrites from a chemical perspective.

[0013] Preferably, the functional deep eutectic solvent comprises choline chloride, urea, anhydrous stannous chloride, anhydrous antimony trichloride, and imidazole; the anhydrous stannous chloride is a tin source; and the anhydrous antimony trichloride is an antimony source. By employing this technical solution, the solvent system with this specific composition is the core of this invention. The deep eutectic solvent formed by choline chloride and urea provides an anhydrous, stable reaction environment with high ion concentration. Anhydrous stannous chloride and anhydrous antimony trichloride serve as metal precursors, while imidazole acts as a key reaction regulator, together constituting an ideal medium for achieving low-temperature in-situ chemical transformation.

[0014] Secondly, the present invention provides a method for preparing a negative electrode current collector for a zinc-nickel battery, employing the following technical solution:

[0015] A method for preparing a zinc-nickel battery negative electrode current collector includes the following steps: S1, providing a three-dimensional porous copper substrate; S2, immersing the three-dimensional porous copper substrate in a functional deep eutectic solvent, wherein the functional deep eutectic solvent contains a tin source, an antimony source, and a reaction regulator; S3, carrying out a reaction at a preset temperature to generate a tin-antimony functional layer in situ on the surface of the three-dimensional porous copper substrate; S4, adding an alkaline substance to the reaction system to terminate the reaction.

[0016] The innovative principles and reaction mechanisms are specifically reflected in:

[0017] Construction of functional media: In step S2, a deep eutectic solvent composed of choline chloride and urea is used as the reaction medium. This medium can effectively dissolve high concentrations of anhydrous stannous chloride and anhydrous antimony trichloride to form a stable metal ion-chloride complex.

[0018] Initiation of the in-situ substitution reaction: In step S3, under heating conditions (e.g., 80–120°C), copper atoms (Cu) on the surface of the three-dimensional porous copper substrate act as a reducing agent, reacting with tin ions (Sn) in the solvent, which have a higher electronegativity. 2+ ) and antimony ions (Sb 3+ A substitution reaction occurs in place; the specific reaction can be simplified to: Cu → Cu n+ +ne - Sn 2+ +2e - →SnSb 3+ +3e - → While copper atoms are oxidized, tin and antimony ions are reduced and directly deposited on the surface of the copper substrate.

[0019] Precise control of the reaction rate: The reaction regulator (preferably imidazole) in step S2 is one of the key points. Imidazole molecules can react with Cu generated in the reaction. n+ Sn in ions or solvents 2+ Sb 3+ The formation of ions into complexes moderately reduces their reactivity, thereby effectively regulating the rate of the substitution reaction. This regulation avoids the problem of a loose, powdery deposit layer caused by an excessively fast reaction, ensuring that the final tin-antimony functional layer is dense, uniform, and firmly bonded.

[0020] Immediate termination of the reaction process: In step S4, by adding a strong alkaline substance (preferably choline solution), the metal ions (Sn) in the solvent can be terminated. 2+ Sb 3+ The rapid reaction generates hydroxide precipitate, instantly reducing the reactant concentration and precisely stopping the displacement reaction. This step ensures a high degree of controllability in the preparation process and consistency between product batches.

[0021] Preferably, in step S2, the functional deep eutectic solvent is made from raw materials, which include choline chloride, urea, tin source, antimony source and imidazole, and the imidazole is a reaction regulator.

[0022] Preferably, in the functional deep eutectic solvent, the molar ratio of choline chloride to urea is 1:(1.8–2.2); the tin source is anhydrous stannous chloride with a concentration of 0.05–0.2 mol / L; the antimony source is anhydrous antimony trichloride with a concentration of 0.02–0.1 mol / L; and the concentration of imidazole is 0.01–0.05 mol / L. By adopting this technical solution, the above-mentioned components and concentration ratios are optimized conditions for achieving a high-quality tin-antimony functional layer, ensuring a sufficient supply of reactants, a moderate reaction rate, and the ideal chemical composition of the final functional layer.

[0023] Preferably, in step S3, the preset temperature is 80-120°C, and the reaction time is 30-120 minutes.

[0024] Preferably, in step S4, the alkaline substance is choline solution.

[0025] Preferably, in step S1, the three-dimensional porous copper substrate is prepared by a non-subtractive processing step including the following actions: first, the copper foil is punched using a punching die, wherein the length of the toothed blade of the punching die is 1.8-2.2 mm, the width is 0.1-0.3 mm, and the parallel spacing between the toothed blades is 0.8-1.2 mm; then, the punched copper foil is stretched and rolled to shape; finally, the shaped three-dimensional porous copper substrate is ultrasonically cleaned sequentially in sodium hydroxide solution and hydrochloric acid solution.

[0026] This invention provides a method for preparing a negative electrode current collector for zinc-nickel batteries. It has the following beneficial effects:

[0027] 1. This invention provides a method for preparing a zinc-nickel battery negative electrode current collector, employing a low-temperature in-situ chemical conversion process based on a functional deep eutectic solvent. The preparation of the functional layer is integrated into a one-pot operation encompassing immersion, reaction, and termination. Compared to traditional aqueous electroplating processes requiring multiple independent plating baths, this method simplifies the process flow, shortens the production cycle, and reduces equipment investment. Furthermore, since the entire reaction is completed in a non-aqueous deep eutectic solvent, the generation of industrial wastewater is fundamentally avoided, reducing the cost and difficulty of subsequent environmental treatment.

[0028] 2. This invention utilizes an in-situ chemical conversion reaction, allowing the three-dimensional porous copper substrate itself to act as both reactant and reducing agent. The tin-antimony functional layer grows in situ from the substrate surface, rather than through simple physical deposition. This unique growth mechanism results in a strong metallurgical or chemical bond interface between the functional layer and the copper substrate, exhibiting extremely high bonding strength. Therefore, the resulting negative electrode current collector effectively resists delamination or pulverization caused by stress changes during battery cycling, ensuring the long-term structural stability and electrochemical performance of the current collector.

[0029] 3. The negative electrode current collector prepared in this invention effectively suppresses the growth of zinc dendrites through the synergistic effect of its three-dimensional porous structure and tin-antimony functional layer. The three-dimensional porous structure provides a large specific surface area, homogenizing the electric field and current distribution, and providing ample space for zinc deposition. Simultaneously, the tin-antimony functional layer with a specific atomic ratio possesses excellent zinc affinity, reducing the nucleation overpotential of zinc. This combination of physical structure and chemical properties fundamentally guides the uniform and dense deposition of zinc ions, improving the cycle life and safety of the battery. Attached Figure Description

[0030] Figure 1 This is a structural diagram of the upper and lower molds of the present invention;

[0031] Figure 2 This is a schematic diagram of the porous copper mesh of the present invention;

[0032] Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle;

[0033] Figure 4 This is a schematic diagram of the copper foil cutting and stretching of the present invention;

[0034] Figure 5 This is a schematic diagram showing the comparison of mass changes in this invention;

[0035] Figure 6 This is a comparative schematic diagram of the surface elemental composition of the present invention;

[0036] Figure 7 This is a schematic diagram of the cycle performance comparison curves of the present invention;

[0037] Figure 8 This is a schematic diagram of the rate performance comparison curve of the present invention;

[0038] Figure 9 This is a schematic diagram of the long-cycle performance comparison curves of the present invention;

[0039] Figure 10 This is a schematic diagram comparing the long-cycle performance of key samples in this invention.

[0040] Among them, 1. Upper mold; 2. Lower mold. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0043] Pure copper foil: T2 state pure copper foil, which is a roll material prepared by rolling process, with the chemical formula Cu, CAS number 7440-50-8, and purity ≥99.9%.

[0044] Choline chloride: Its chemical name is 2-hydroxyethyltrimethylammonium chloride, and its chemical formula is C5H. 14 ClNO, CAS number 67-48-1, is a white crystalline powder of analytical grade.

[0045] Urea: Its chemical name is carbamide, its chemical formula is CH4N2O, its CAS number is 57-13-6, and it is a white crystalline or powder of analytical grade.

[0046] Anhydrous stannous chloride: Its chemical name is stannous dichloride, its chemical formula is SnCl2, its CAS number is 7772-99-8, and it is a white crystalline powder of analytical grade.

[0047] Anhydrous antimony trichloride: Its chemical name is antimony trichloride, its chemical formula is SbCl3, its CAS number is 10025-91-9, and it is a colorless or slightly yellow crystalline block of analytical grade.

[0048] Imidazole: Its chemical name is 1,3-diazacyclopentadiene, its chemical formula is C3H4N2, its CAS number is 288-32-4, and it is a white or pale yellow flaky crystal of analytical grade.

[0049] Sodium hydroxide: chemical formula NaOH, CAS number 1310-73-2, is a white solid granule or flake-like substance of analytical grade.

[0050] Hydrochloric acid: an aqueous solution of hydrogen chloride, chemical formula HCl, CAS number 7647-01-0, analytical grade, concentrated solution with a mass fraction of 36-38 wt%.

[0051] Choline solution: an aqueous solution of choline hydroxide, with the chemical formula C5H. 15NO2, CAS number 123-41-1, is a 45 wt% aqueous solution.

[0052] Anhydrous ethanol: Its chemical name is ethanol, its chemical formula is C2H5OH, its CAS number is 64-17-5, it is of analytical grade, and its purity is ≥99.7%.

[0053] Sintered nickel hydroxide cathode sheet: a commercial cathode material used in zinc-nickel batteries. The main active material is nickel hydroxide, with the chemical formula Ni(OH)2 and CAS number 12054-48-7.

[0054] Zinc sulfate: chemical formula ZnSO4, CAS number 7733-02-0, is a white powder of analytical grade, used to prepare electrolytes.

[0055] Zinc foil: metallic zinc foil with a purity of ≥99.9%, chemical formula Zn, CAS number 7440-66-6, used as counter electrode and reference electrode.

[0056] Preparation example:

[0057] All chemical components used in this invention, including choline chloride, urea, anhydrous stannous chloride, anhydrous antimony trichloride, and imidazole, are commercially available chemicals with well-defined chemical structures and require no special preparation. The following preparation examples are only used to illustrate the general preparation process of functional deep eutectic solvents (DES) as reaction media.

[0058] Preparation Example 1: Preparation of Functional Deep Eutectic Solvent (DES)

[0059] All chemicals used in this preparation example were analytical grade (AR) or higher. In a 500 mL three-necked flask equipped with a magnetic stirrer and temperature sensor, 139.6 g (1.0 mol) of choline chloride and 120.1 g (2.0 mol) of urea were added. The entire apparatus was connected to a nitrogen source to ensure operation under an inert atmosphere. The three-necked flask was placed in a constant-temperature oil bath, and the oil bath temperature was set and precisely controlled at 80 ± 2 °C. The magnetic stirrer was turned on, and the stirring speed was controlled at 300-500 rpm. Under these conditions, stirring was continued for about 1-2 hours until all solids were completely dissolved, forming a visually homogeneous, clear, colorless to pale yellow transparent liquid, which is the matrix deep eutectic solvent.

[0060] While maintaining the temperature and stirring conditions, add the predetermined amounts of anhydrous stannous chloride, anhydrous antimony trichloride, and imidazole to the matrix solvent in sequence; continue stirring for about 30-60 minutes until all added solid components are completely dissolved; to ensure the consistency of the solvent, a sample can be taken and its transmittance measured at a wavelength of 600 nm using a spectrophotometer. The transmittance should not be less than 98% to confirm that the solvent is completely clear and free of suspended impurities.

[0061] The prepared functional deep eutectic solvent was transferred while hot into a brown screw-top glass bottle with a polytetrafluoroethylene (PTFE) gasket, sealed under a nitrogen atmosphere, and stored in a dry environment at room temperature (25±5℃) for later use; the specific amount of each functional component added is described in detail in subsequent examples.

[0062] Example 1

[0063] This embodiment provides a method for preparing a negative electrode current collector for a zinc-nickel battery, including the following steps:

[0064] (1) Preparation of three-dimensional porous copper substrate: Refer to Appendix Figures 1-4 A non-subtractive processing method was used to process 80µm thick T2 state pure copper foil using a punching die. The punching die includes an upper die 1 and a lower die 2. The toothed blades of the upper die 1 and lower die 2 are 2.0mm long and 0.2mm wide, with a parallel spacing of 1.0mm between the blades and a staggered distance of 1.0mm between the upper and lower blades. The punched copper foil is stretched and then rolled to obtain a thickness of 0.25mm and an areal density of 350g / m³. 2 A three-dimensional porous copper mesh was prepared. The copper mesh has a uniform rhomboid aperture with a width of approximately 2 mm and a length of approximately 2 mm. Finally, the copper mesh was ultrasonically cleaned in a 4.0 mol / L sodium hydroxide solution at 60 °C for 3 minutes, and then ultrasonically cleaned in a 2.0 mol / L hydrochloric acid solution at room temperature for 2 minutes. After each step, it was rinsed with deionized water until neutral. Finally, it was rinsed with anhydrous ethanol and dried in a vacuum oven at 70 °C and a vacuum degree of less than 100 Pa for 3 hours for later use.

[0065] (2) Preparation of functional deep eutectic solvent: Following the method of Preparation Example 1, anhydrous stannous chloride, anhydrous antimony trichloride and imidazole of analytical grade were added to the matrix solvent prepared from 1.0 mol of analytical grade choline chloride and 2.0 mol of analytical grade urea, and stirred until completely dissolved, so that the total volume of the functional deep eutectic solvent was about 200 mL, and the final concentrations of each component were: anhydrous stannous chloride 0.1 mol / L, anhydrous antimony trichloride 0.05 mol / L, and imidazole 0.025 mol / L.

[0066] (3) Low-temperature in-situ chemical transformation: The clean three-dimensional porous copper mesh substrate prepared in step (1) was completely immersed in 200 mL of the functional deep eutectic solvent prepared in step (2). The solution was placed in a reaction vessel equipped with magnetic stirring and temperature control. The temperature was increased to 100 °C at a rate of 5 ± 0.5 °C / min, and the magnetic stirring was turned on, with the speed controlled at 200 ± 10 rpm. The reaction was carried out in a constant temperature environment of 100 ± 2 °C for 60 minutes.

[0067] (4) Reaction termination: After the reaction is completed, choline solution with a mass fraction of 45wt% is added to the system by peristaltic pump. The dropping rate is controlled at 1.0mL / min, and a total of 2.0mL is added over a time of 2 minutes to ensure that the reaction is terminated accurately.

[0068] (5) Post-processing: Remove the current collector from the solution, ultrasonically clean it 3 times with anhydrous ethanol for 3 minutes each time, then rinse it with deionized water for 1 minute, and finally dry it in a vacuum oven at 70°C and a vacuum degree of less than 100Pa for 6 hours to obtain the finished product.

[0069] Example 2

[0070] This embodiment provides a method for preparing a negative electrode current collector for a zinc-nickel battery. The steps are basically the same as in Example 1, except that:

[0071] In step (3) low-temperature in-situ chemical transformation, the reaction temperature is controlled at 80±2℃ and the reaction time is 120 minutes; all other operations, including heating rate, stirring speed, reaction termination conditions and post-treatment conditions, are exactly the same as in Example 1.

[0072] Example 3

[0073] This embodiment provides a method for preparing a negative electrode current collector for a zinc-nickel battery. The steps are basically the same as in Example 1, except that:

[0074] In step (3) low-temperature in-situ chemical transformation, the reaction temperature is controlled at 120±2℃ and the reaction time is 30 minutes; all other operations, including heating rate, stirring speed, reaction termination conditions and post-treatment conditions, are exactly the same as in Example 1.

[0075] Example 4

[0076] This embodiment provides a method for preparing a negative electrode current collector for a zinc-nickel battery. The steps are basically the same as in Example 1, except that:

[0077] In step (2) preparation of the functional deep eutectic solvent, the final concentrations of each component are: anhydrous stannous chloride 0.2 mol / L, anhydrous antimony trichloride 0.1 mol / L, and imidazole 0.05 mol / L. All other operations, including substrate preparation, reaction process parameters, reaction termination conditions and post-treatment conditions, are exactly the same as in Example 1.

[0078] Example 5

[0079] This embodiment provides a method for preparing a negative electrode current collector for a zinc-nickel battery. The steps are basically the same as in Example 1, except that:

[0080] In step (2) preparation of the functional deep eutectic solvent, the final concentrations of each component are: anhydrous stannous chloride 0.05 mol / L, anhydrous antimony trichloride 0.02 mol / L, and imidazole 0.01 mol / L. All other operations, including substrate preparation, reaction process parameters, reaction termination conditions and post-treatment conditions, are exactly the same as in Example 1.

[0081] Comparative Example 1: Compared with Example 1, the difference is that only step (1) was performed to prepare a three-dimensional porous copper substrate without any subsequent chemical conversion treatment. This substrate was directly used as the sample of Comparative Example 1.

[0082] Comparative Example 2: Compared with Example 1, the difference is that the three-dimensional porous copper substrate in step (1) was replaced with a commercially available ordinary copper foam with similar porosity and areal density, and the copper foam was subjected to the same pretreatment and subsequent chemical conversion steps as in Example 1.

[0083] Comparative Example 3: Compared with Example 1, the difference is that: instead of using the low-temperature in-situ chemical conversion method, the water-based electroplating was carried out on the three-dimensional porous copper substrate prepared in step (1) of Example 1 by referring to the industry standard electroplating practice; specifically, a tin layer was deposited in an acidic sulfate plating solution and an antimony layer was deposited in a tartrate plating solution. After the tin-antimony functional layer was finally formed, it was dried and treated according to the method of step (5) of Example 1.

[0084] Comparative Example 4: Compared with Example 1, the difference is that anhydrous antimony trichloride is not added to the functional deep eutectic solvent prepared in step (2), and all other aspects are the same.

[0085] Comparative Example 5: Compared with Example 1, the difference is that anhydrous stannous chloride is not added to the functional deep eutectic solvent prepared in step (2), and all other aspects are the same.

[0086] Comparative Example 6: Compared with Example 1, the difference is that: imidazole is not added to the functional deep eutectic solvent prepared in step (2), and the reaction termination operation of adding choline solution is not performed in step (4). After the reaction is completed, the current collector is directly taken out from the hot solution for post-processing. All other aspects are the same.

[0087] Part 1: Feasibility Verification Testing of the Solution

[0088] Test Example 1.1: Mass Change Test

[0089] Experimental Description: This test aims to verify that the low-temperature in-situ chemical conversion method proposed in this invention can successfully introduce new substances onto the surface of a three-dimensional porous copper substrate by accurately measuring the mass change of the sample before and after chemical conversion.

[0090] Experimental steps:

[0091] Sample preparation: Samples for Example 1 and Comparative Example 1 were prepared respectively; to ensure the reliability of the data, three parallel samples were prepared for each group and cut into squares with a size of 2cm×2cm.

[0092] Initial mass weighing: Before chemical conversion treatment, all samples (including the substrates to be used to prepare the samples of Example 1 and Comparative Example 1) were dried in a vacuum oven at 70°C and a vacuum degree of less than 100 Pa for 3 hours to completely remove surface adsorbed moisture. After the samples cooled to room temperature, each sample was weighed using an analytical balance with an accuracy of 0.01 mg (model: Mettler-Toledo-ME204), and its initial mass was recorded. .

[0093] Sample preparation: The three substrate samples used to prepare Example 1 were prepared according to the complete steps of Example 1; the three samples of Comparative Example 1 were not prepared in any way.

[0094] Final mass weighing: The processed samples of Example 1 and Comparative Example 1 were thoroughly dried again under the drying conditions of step 2; after the samples cooled to room temperature, each sample was weighed using the same analytical balance, and its final mass was recorded. .

[0095] Data calculation:

[0096] Calculate the mass change for each sample: ;

[0097] Calculate the weight gain surface density of each sample: (Where A is the macroscopic surface area of ​​the sample, which is 4 cm² in this case.) 2 ).

[0098] The experimental data are shown in Table 1:

[0099] Table 1: Test data on the texture change of samples from Example 1 and Comparative Example 1

[0100]

[0101] Conclusion: Refer to Appendix Figure 5 The test data in Table 1 clearly show that the sample prepared according to the method in Example 1 exhibited a significant and repeatable increase in mass after treatment, with an average increase in surface density reaching 5.06 mg / cm³. 2 In contrast, the sample in Comparative Example 1, after undergoing the same measurement procedure, maintained a substantially unchanged mass within the measurement error range;

[0102] The net increase in sample mass is direct evidence of the formation of new substances. This mass increase is attributed to Sn during the low-temperature in-situ chemical transformation. 2+ and Sb 3+ Ions are reduced in a functional deep eutectic solvent medium and react with copper atoms on the substrate surface, thereby generating a tin-antimony functional layer in situ on the framework of a three-dimensional porous copper mesh. The test results directly confirm the feasibility of the technical solution proposed in this invention, that is, a new active material layer can be successfully introduced and loaded on a three-dimensional porous copper substrate using a functional deep eutectic solvent system.

[0103] Test Example 1.2: Surface Elemental Composition Analysis

[0104] Experimental Description: This test aims to quantitatively analyze the types and relative contents of elements in the sample surface layer using X-ray photoelectron spectroscopy (XPS) to verify whether the new functional layer has been successfully generated from the perspective of chemical composition.

[0105] Experimental steps:

[0106] Sample preparation: Take the samples prepared in Example 1 and Comparative Example 1 respectively, cut them into standard sizes of 1cm×1cm, and use them for energy dispersive spectroscopy analysis.

[0107] Test execution: X-ray photoelectron spectroscopy was used for testing; the sample was fixed on the sample holder and sent into the ultra-high vacuum analysis chamber; a monochromatic Al-Kα source was used as the excitation source; in order to remove the surface adsorbed contaminant layer, the sample surface was first cleaned by low-energy sputtering for 30 seconds using an argon ion beam before analysis.

[0108] Data acquisition: A full-spectrum scan was performed on the surface of each sample after sputtering to determine the types of elements present.

[0109] Data analysis: The full spectrum data is analyzed, and the atomic percentage (At%) of each major element in the sample surface layer (approximately 5-10 nm depth range) is calculated by combining the area of ​​the characteristic peaks of each element with the relative sensitivity factor (RSF). To ensure the representativeness of the results, two parallel samples are tested for each sample type.

[0110] The experimental data are shown in Table 2:

[0111] Table 2: Surface elemental composition (atomic percentage, At%) of Samples from Example 1 and Comparative Example 1

[0112]

[0113] Note: Trace amounts of carbon (C) introduced by surface adsorption are not listed in the table.

[0114] Conclusion: Refer to Appendix Figure 6The XPS test data in Table 2 show that the surface composition of the sample in Comparative Example 1 is almost entirely composed of copper, which is consistent with the chemical nature of its pure copper substrate.

[0115] In contrast, high concentrations of tin (average 18.29 At%) and antimony (average 9.03 At%) were detected on the surface of the sample in Example 1, while the relative content of copper decreased accordingly. The detection of tin and antimony, and their atomic ratio of approximately 2:1, is consistent with the Sn content set in the functional deep eutectic solvent. 2+ and Sb 3+ The concentration ratios (0.1 mol / L vs 0.05 mol / L) are highly consistent.

[0116] This result provides direct chemical evidence for the successful formation of the functional layer; it confirms that during the low-temperature in-situ chemical transformation, tin and antimony ions in the solvent are not simply physically adsorbed, but rather enriched on the copper substrate surface through a chemical reaction, forming a stable new phase layer containing the target functional elements. This test definitively verifies the effectiveness of the technical solution of this invention at the elemental composition level.

[0117] Test Example 1.3: Electrochemical Cyclic Performance Test

[0118] Experimental Description: This test aims to evaluate and compare the electrochemical performance of zinc anodes prepared with different current collectors through constant current charge-discharge cycle testing. The core indicators are specific capacity and cycle stability.

[0119] Experimental steps:

[0120] Negative electrode preparation: Zinc oxide (ZnO) powder, polyvinylidene fluoride (PVDF) binder, and Super-P conductive carbon black were mixed in N-methylpyrrolidone (NMP) solvent at a mass ratio of 8:1:1 and ball-milled for 4 hours to form a uniform negative electrode slurry. This slurry was then uniformly coated onto the current collector samples of Examples 1, 1, 2, 3, 4, 5, and 6, with the surface loading of the active material ZnO controlled at 5.0 ± 0.2 mg / cm³. 2 The coated electrode sheet was dried under vacuum at 70°C for 12 hours, and then punched into a circular electrode with a diameter of 14 mm.

[0121] Battery assembly: The prepared circular electrode is used as the working electrode, the sintered nickel hydroxide electrode is used as the counter electrode, and the glass fiber membrane is used as the separator. The assembly is carried out in a CR2032 button cell case. The electrolyte is a 6.0 mol / L KOH aqueous solution containing 0.5 mol / L ZnO. The entire assembly process is carried out in an argon-filled glove box.

[0122] Electrochemical testing: Using a battery testing system, constant current charge-discharge tests were performed on the assembled battery at room temperature (25±2℃); the charge-discharge voltage window was set to 1.0V to 1.9V; the test current density was set to 1C (based on the theoretical capacity of ZnO). The discharge specific capacity of the battery was recorded at the 1st and 100th cycles.

[0123] Data calculation:

[0124] Discharge specific capacity (mAh / g) = Discharge capacity (mAh) / Mass of active material (g);

[0125] Capacity retention rate (%) = (Specific capacity at discharge cycle 100 / Specific capacity at discharge cycle 1) × 100%;

[0126] The experimental data are shown in Table 3:

[0127] Table 3: Electrochemical cycling performance data of different samples at 1C rate

[0128]

[0129] Conclusion: Refer to Appendix Figure 7 The electrochemical test data in Table 3 show that the current collector prepared by the method in Example 1 has a capacity retention rate of 91.1% for its corresponding zinc anode after 100 cycles, which is significantly higher than that of all comparative examples.

[0130] The battery capacity of Comparative Example 1 (untreated copper mesh) decayed rapidly, with a capacity retention of only 44.9%, mainly due to severe zinc dendrite growth and electrode pulverization during cycling. Although the performance of Comparative Example 4 (antimony-free) and Comparative Example 5 (tin-free) was better than that of Comparative Example 1, it was far inferior to that of Example 1. This confirms that the coexistence of tin and antimony has a synergistic effect on stabilizing the zinc anode interface, and neither can be omitted. The performance of Comparative Example 6 (without reaction termination step) also deteriorated rapidly, indicating that the step of precisely terminating the reaction with imidazole and choline alkaline solution is crucial for forming a functional layer with uniform structure and electrochemical performance.

[0131] The performance degradation of Comparative Example 2 (using commercially available copper foam) was also severe, with a capacity retention rate of only 58.5%. This indicates that the three-dimensional porous copper substrate prepared by non-subtractive processing in step (1) of the present invention has a specific pore structure and skeleton surface morphology that are more conducive to the uniform loading of the functional layer and the uniform distribution of current in the subsequent electrochemical reaction, which is not available in ordinary copper foam.

[0132] Comparative Example 3 (using a traditional electroplating method) had a high initial capacity but poor cycle stability, with a capacity retention rate of 63.4%. This indicates that, compared with simple physical stacking (electroplating), the low-temperature in-situ chemical conversion method used in this invention can form an interface layer with stronger adhesion to the copper substrate. This interface layer is not prone to pulverization and peeling during long-term cycling, thus ensuring the integrity of the electrode structure.

[0133] In summary, the tin-antimony functional layer generated in situ on the current collector surface in Example 1 can effectively homogenize the electric field distribution and guide the uniform deposition and dissolution of zinc, thereby inhibiting the growth of zinc dendrites and the occurrence of side reactions. This directly improves the cycle life and coulombic efficiency of the zinc anode, verifying the effectiveness of this technical solution in improving the performance of zinc-nickel batteries.

[0134] Part Two: Performance Comparison Test

[0135] Test Example 2.1: Rate Performance Test

[0136] Experimental Description: This test aims to evaluate the effects of different preparation process parameters (reaction temperature, reaction time, solvent component concentration) on the electrochemical performance of the negative electrode current collector; through constant current charge-discharge tests at different current densities, the capacity performance and stability of each sample at high rates are examined.

[0137] Experimental steps:

[0138] Battery fabrication: Using the current collectors prepared in Examples 1, 2, 3, 4 and 5 respectively, coin cells with the same active material loading were prepared according to the same method in Test Example 1.3.

[0139] Test procedure: The battery was tested at room temperature (25±2℃) using a battery testing system; the battery was activated 5 times at a current density of 0.5C; then, charge and discharge tests were performed sequentially at current densities of 0.5C, 1C, 2C, 5C and 10C, with 5 cycles at each rate; finally, the current density was restored to 0.5C and cycled 5 times again to verify the recoverability of the capacity.

[0140] Data recording: Record the stable discharge specific capacity of the 5th cycle at each rate.

[0141] The experimental data are shown in Table 4:

[0142] Table 4: Discharge specific capacity (mAh / g) of samples from different embodiments at various rates

[0143]

[0144] Conclusion: Refer to Appendix Figure 8As shown in Table 4, the current collectors prepared in all examples exhibit good rate performance, but there are significant differences under different process parameters.

[0145] The sample in Example 1 exhibited the highest discharge specific capacity across a wide current density range from 0.5C to 10C, and still released a capacity of 401.5 mAh / g at high rate (10C), demonstrating excellent fast charge and discharge capability. In contrast, the samples in Example 2 (low temperature, long time) and Example 3 (high temperature, short time) showed a certain degree of decrease in high rate performance. This indicates that matching the reaction temperature and time is the key to forming the optimal surface structure. Temperatures that are too high or too low may affect the microstructure and conductivity of the functional layer, thereby restricting the electrochemical reaction kinetics under high current.

[0146] The results of Example 4 (high concentration) and Example 5 (low concentration) reveal the effect of precursor concentration; too low a concentration (Example 5) leads to a general decline in sample performance, possibly due to the generated functional layer being too sparse or incomplete; while too high a concentration (Example 4) shows acceptable performance at low and medium magnification, but the capacity decay is more obvious at high magnification than in Example 1, which may be related to the generated functional layer being too thick and too dense, increasing the resistance to ion diffusion.

[0147] In summary, the test results confirm the rationality of the preparation parameter window proposed in this invention; the intermediate conditions used in Example 1 can construct a tin-antimony functional layer with optimized structure and composition. This functional layer has both high conductivity and excellent control over zinc ion deposition / dissolution, thereby achieving the best electrochemical rate performance.

[0148] Test Example 2.2: Long Cycle Stability Test

[0149] Experimental Description: This test aims to evaluate the stability of the zinc anode corresponding to the current collector prepared under different process parameters during long-term cycling at high current density.

[0150] Experimental steps:

[0151] Battery fabrication: Using the current collectors prepared in Examples 1, 2, 3, 4 and 5 respectively, coin cells with the same active material loading were prepared according to the same method in Test Example 1.3.

[0152] Test procedure: Use a battery test system to perform constant current charge-discharge cycle test at room temperature (25±2℃); set the test current density to 2C; set the charge-discharge voltage window to 1.0V to 1.9V.

[0153] Data recording: The battery discharge specific capacity was recorded at the 1st, 100th, 300th and 500th cycles after 500 consecutive charge-discharge cycles.

[0154] Data calculation:

[0155] Capacity retention rate at 500th cycle (%) = (Specific discharge capacity at 500th cycle / Specific discharge capacity at 1st cycle) × 100%;

[0156] The experimental data are shown in Table 5:

[0157] Table 5: Long-cycle performance data of samples from different embodiments at 2C rate

[0158]

[0159] Conclusion: Refer to Appendix Figure 9 The long-cycle test data in Table 5 show that the anode prepared by the process parameters of Example 1 exhibits the best long-term cycling stability at a high rate of 2C; after 500 cycles, the sample can still maintain 85.8% of the initial capacity, demonstrating the structural stability of its functional layer under long-term electrochemical stress.

[0160] The capacity retention rates of the samples in Example 2 (low temperature, long time) and Example 3 (high temperature, short time) were significantly lower than those in Example 1, indicating that the matching of reaction temperature and time is crucial for the formation of a stable functional layer. Inappropriate reaction kinetic conditions may lead to weak bonding between the generated functional layer and the matrix, or the presence of internal stress, which may result in structural damage during long-term cycling.

[0161] The results of Example 4 (high concentration) and Example 5 (low concentration) further confirmed the key role of solvent component concentration; the low concentration (Example 5) resulted in the worst cycling stability, with a capacity retention of only 40.5%, which may be related to incomplete functional layer coverage and inability to effectively suppress zinc dendrites; while the high concentration (Example 4) was better than Example 5, but the stability was still worse than Example 1, which is presumably because the excessively thick functional layer may have mechanically peeled off due to volume changes during cycling.

[0162] Therefore, the test results confirm that the combination of process parameters used in Example 1 can produce the most stable functional layer with the strongest bond to the substrate, thereby effectively suppressing the irreversible capacity decay of the zinc anode under high current density and achieving the best long-cycle performance.

[0163] Test Example 2.3: Comparative Test of Long-Term Cyclic Stability of Key Samples

[0164] Experimental Description: This test aims to compare the optimized sample of the present invention (Example 1) with key comparative samples (pure substrate, different substrates, different preparation methods) to further verify the comprehensive advantages of the present invention in substrate selection and preparation method, especially the long-term cycling stability under high current density.

[0165] Experimental steps:

[0166] Battery fabrication: Select the current collectors prepared in representative Examples 1, 1, 2 and 3, and prepare coin cells with the same active material loading according to the same method in Test Example 1.3.

[0167] Test procedure: A constant current charge-discharge cycle test was performed using a battery testing system at room temperature (25±2°C). The test current density was set to 2C; the charge-discharge voltage window was set to 1.0V to 1.9V.

[0168] Data recording: The battery discharge specific capacity was recorded at the 1st, 100th, 300th and 500th cycles after 500 consecutive charge-discharge cycles.

[0169] Data calculation: Capacity retention rate at 500th cycle (%) = (Specific discharge capacity at 500th cycle / Specific discharge capacity at 1st cycle) × 100%;

[0170] The experimental data are shown in Table 6:

[0171] Table 6: Long-cycle performance data of key samples at 2C rate

[0172]

[0173] Conclusion: Refer to Appendix Figure 10 According to the data in Table 6, after 500 long cycles at 2C rate, the capacity retention rate of the sample in Example 1 was as high as 85.8%, while that of Comparative Example 1 (pure copper mesh) was almost completely ineffective, with a capacity retention rate of only 22.0%.

[0174] Although Comparative Example 2 (commercially available copper foam) and Comparative Example 3 (electroplation method) showed high capacity in the initial stage of cycling, they exhibited rapid capacity decay during long-term cycling, with capacity retention rates below 45% after 500 cycles. This strongly demonstrates that the combination of the specific substrate structure and the in-situ chemical conversion method used in this invention is the fundamental reason for achieving high stability; this combination ensures excellent physical and electrochemical stability between the functional layer and the substrate, thereby effectively suppressing failure modes such as zinc dendrite formation and electrode pulverization even under high-intensity charge and discharge conditions.

Claims

1. A zinc-nickel battery negative current collector, characterized in that, The application relates to a three-dimensional porous copper substrate, which comprises the following steps: S1, providing a three-dimensional porous copper substrate; wherein the three-dimensional porous copper substrate is prepared through a non-subtractive machining step comprising the following actions: S1-1, punching a copper foil by using a punching die, wherein the length of the tooth cutter of the punching die is 1.8-2.2 mm, the width is 0.1-0.3 mm, and the parallel distance between the tooth cutters is 0.8-1.2 mm; S1-2, stretching and roll pressing the punched copper foil to be shaped; and S1-3, sequentially ultrasonically cleaning the shaped three-dimensional porous copper substrate in sodium hydroxide solution and hydrochloric acid solution; S2, immersing the three-dimensional porous copper substrate in a functional deep eutectic solvent, wherein the functional deep eutectic solvent comprises a tin source, an antimony source and a reaction control agent; wherein the functional deep eutectic solvent is prepared from raw materials, the raw materials comprise choline chloride, urea, the tin source, the antimony source and imidazole, and the imidazole is the reaction control agent; S3, carrying out a reaction at a temperature of 80-120 DEG C to generate a tin-antimony functional layer in situ on the surface of the three-dimensional porous copper substrate; and S4, adding an alkaline substance to the reaction system to terminate the reaction. A tin-antimony functional layer is formed on the surface of the three-dimensional porous copper substrate. The tin-antimony functional layer is prepared by low-temperature in-situ chemical conversion of the three-dimensional porous copper substrate in a functional deep eutectic solvent, the temperature of the low-temperature in-situ chemical conversion is 80-120 DEG C, and the functional deep eutectic solvent comprises a tin source, an antimony source and imidazole; wherein the functional deep eutectic solvent comprises choline chloride, urea, anhydrous stannous chloride, anhydrous antimony trichloride and imidazole; the anhydrous stannous chloride is the tin source; and the anhydrous antimony trichloride is the antimony source. In the tin-antimony functional layer, the atomic ratio of tin to antimony is (1.5-2.5):

1.

2. A zinc-nickel battery negative current collector according to claim 1, characterized in that, The application relates to a three-dimensional porous copper substrate, which comprises the following steps: S1, providing a three-dimensional porous copper substrate; wherein the three-dimensional porous copper substrate is prepared through a non-subtractive machining step comprising the following actions: S1-1, punching a copper foil by using a punching die, wherein the length of the tooth cutter of the punching die is 1.8-2.2 mm, the width is 0.1-0.3 mm, and the parallel distance between the tooth cutters is 0.8-1.2 mm; S1-2, stretching and roll pressing the punched copper foil to be shaped; and S1-3, sequentially ultrasonically cleaning the shaped three-dimensional porous copper substrate in sodium hydroxide solution and hydrochloric acid solution; S2, immersing the three-dimensional porous copper substrate in a functional deep eutectic solvent, wherein the functional deep eutectic solvent comprises a tin source, an antimony source and a reaction control agent; wherein the functional deep eutectic solvent is prepared from raw materials, the raw materials comprise choline chloride, urea, the tin source, the antimony source and imidazole, and the imidazole is the reaction control agent; S3, carrying out a reaction at a temperature of 80-120 DEG C to generate a tin-antimony functional layer in situ on the surface of the three-dimensional porous copper substrate; and S4, adding an alkaline substance to the reaction system to terminate the reaction.

3. A method of producing a negative current collector for a zinc-nickel battery according to any one of claims 1-2, characterized in that, In the functional deep eutectic solvent: The molar ratio of choline chloride to urea is 1:(1.8-2.2); The tin source is anhydrous stannous chloride, and the concentration of the anhydrous stannous chloride is 0.05-0.2 mol / L; The antimony source is anhydrous antimony trichloride, and the concentration of the anhydrous antimony trichloride is 0.02-0.1 mol / L; The concentration of the imidazole is 0.01-0.05 mol / L. In step S3, the reaction time is 30-120 minutes. In step S4, the alkaline substance is choline lye. ​ 4. A method of producing a zinc-nickel battery negative current collector according to claim 3, characterized in that, ​ ​ ​ ​ ​ 5. A method of producing a zinc-nickel battery negative current collector according to claim 3, characterized in that, ​ 6. A method of producing a zinc-nickel battery negative current collector according to claim 3, characterized in that, ​

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