Water-based zinc ion battery containing brass screen, zinc negative electrode material and preparation method of zinc negative electrode material

Abstract

The invention discloses an aqueous zinc ion battery containing a brass screen, a zinc negative electrode material and a preparation method of the zinc negative electrode material, and relates to the technical field of negative electrode materials of aqueous zinc ion batteries. Aiming at the problems of dendritic crystal growth, uneven ion transfer, unbalanced charge distribution and the like of the zinc negative electrode of the aqueous zinc ion battery, a brass net is embedded into the surface of the zinc negative electrode, and the porous characteristic of the brass net is utilized to regulate and control an ion transfer path, optimize the ion flux uniformity and accelerate ion migration; by utilizing the uniform surface characteristic of the copper-zinc alloy, uniform zinc ion nucleation sites are provided, and zinc is guided to be uniformly deposited; by virtue of good chemical stability of the brass net, side reaction is inhibited; the porous structure of the brass net is utilized to improve electric field distribution and promote uniform distribution of charges.

Description

Technical Field

[0001] This invention relates to the field of negative electrode materials for aqueous zinc-ion batteries, and particularly to aqueous zinc-ion batteries containing brass mesh, zinc negative electrode materials, and their preparation methods. Background Technology

[0002] Among existing clean energy sources, aqueous zinc-ion batteries (AZIBs) with zinc-containing anodes are considered a preferred direction for next-generation energy storage batteries due to the advantages of zinc (Zn), including its high theoretical capacity (820 mAh / g), low plating / stripping potential (-0.76 V relative to the standard hydrogen electrode), and ease of processing. Furthermore, aqueous zinc-ion batteries use aqueous electrolytes, resulting in higher safety performance and greater environmental friendliness.

[0003] To address the problems in aqueous zinc-ion batteries, such as zinc dendrite growth causing continuous puncture of the separator, leading to short circuits, significantly shortened cycle life, and reduced coulombic efficiency, as well as the corrosion of the zinc anode due to interfacial side reactions, resulting in "dead zinc" and weakened battery capacity and reversibility, current technologies commonly employ surface-modification coatings for the zinc anode and optimization of the electrolyte composition. Therefore, exploring suitable fabrication processes for zinc anode materials is crucial for achieving technological breakthroughs in aqueous zinc-ion batteries. Summary of the Invention

[0004] To address the problems of dendrite growth and uneven ion and charge distribution in existing aqueous zinc-ion batteries, this invention provides an aqueous zinc-ion battery containing a brass mesh, a zinc anode material, and its preparation method. This invention utilizes the structural and performance advantages of a brass mesh embedded in the zinc anode surface to regulate zinc deposition behavior, optimize ion transport and charge distribution, suppress zinc dendrite formation, and improve battery cycle stability and electrochemical performance. This invention is specifically achieved through the following technical solutions.

[0005] An aqueous zinc-ion battery containing a brass mesh, wherein the brass mesh is embedded on a zinc sheet / zinc foil and the brass mesh is located between the zinc sheet / zinc foil and a separator.

[0006] Furthermore, the brass mesh has a mesh count of 20-200.

[0007] Furthermore, the brass mesh has a mesh count of 80-100.

[0008] Furthermore, the thickness of the brass mesh is 50-200 μm.

[0009] Furthermore, the thickness of the brass mesh is 100 μm.

[0010] Furthermore, the thickness of the zinc sheet / zinc foil is 20 μm.

[0011] Furthermore, the aqueous zinc-ion battery structure also includes a positive electrode material and an electrolyte, the electrolyte being used to completely wet the separator.

[0012] In the structure of the aqueous zinc-ion battery provided by this invention, the brass mesh possesses a unique porous structure, exhibiting excellent conductivity and chemical stability. The rational application of the brass mesh to the zinc anode design of this invention can regulate zinc ion deposition behavior, optimize interface characteristics, thereby suppressing zinc dendrite growth, improving charge and ion distribution uniformity, and enhancing battery cycle stability.

[0013] In the structure of the aqueous zinc-ion battery provided by this invention, a brass mesh is located between the negative electrode sheet (zinc sheet / zinc foil) and the separator, and the brass mesh needs to be tightly fitted to the negative electrode sheet. The tight fitting method provided by this invention involves first attaching the brass mesh to the zinc negative electrode, and then, due to the pressure from the assembly equipment during battery assembly, the brass mesh is ultimately embedded in the surface of the zinc negative electrode sheet in the final battery product. It is also necessary to ensure that the surface and edges of the brass mesh in contact with the separator are free of burrs and protrusions, and that the pores of the brass mesh are evenly distributed. In the structure of the aqueous zinc-ion battery provided by this invention, the brass mesh and the negative electrode sheet can be made to match their dimensions through stamping and cutting. Pre-treatment through the stamping process ensures structural stability and ion transport channels.

[0014] The interface between the brass mesh and the zinc anode enhances structural integrity and improves interface stability during cycling through physical anchoring and uniform charge distribution. The aqueous zinc-ion battery assembled using the method of this invention optimizes ion conduction and charge distribution, suppresses zinc dendrite formation, and improves battery cycle life and electrochemical performance. Ultimately, it achieves efficient and stable zinc-ion storage and conversion, making it suitable for various fields such as energy storage systems and portable electronic devices.

[0015] The present invention also provides a method for preparing the above-mentioned aqueous zinc-ion battery containing brass mesh, wherein the zinc sheet / zinc foil and the brass mesh are sequentially placed inside the negative electrode shell; the smooth surface of the zinc sheet / zinc foil faces the brass mesh;

[0016] Place the diaphragm in the middle, and drip in the electrolyte to completely wet the diaphragm;

[0017] Insert the positive electrode sheet with the smooth side of the positive electrode sheet facing the separator, place the gasket and spring sheet, snap on the positive electrode shell, and apply pressure to seal the brass mesh onto the zinc sheet / zinc foil to obtain the aqueous zinc-ion battery.

[0018] The present invention also provides an aqueous zinc-ion battery negative electrode material, comprising zinc sheet / zinc foil and brass mesh; the brass mesh is embedded on the zinc sheet / zinc foil.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] This invention uses brass mesh to prepare the negative electrode material for aqueous zinc-ion batteries, forming a unique microstructure that can precisely control zinc ion nucleation and deposition, suppress zinc dendrite growth, improve ion transfer efficiency and charge distribution uniformity, stabilize the interface, reduce side reactions, and enhance battery cycle stability and charge-discharge efficiency. The material is low-cost and simple to process, suitable for diverse scenarios, and enhances practical value, making it applicable to energy storage systems, portable electronic devices, and other fields. Attached Figure Description

[0021] Figure 1 Comparison images of the electrode sheet and brass mesh.

[0022] Figure 2 This is a photograph of a battery where pressure is applied during assembly to embed the BM (Branch Injector) onto a zinc sheet.

[0023] Figure 3 XRD comparison images of brass mesh and the zinc and copper foil used.

[0024] Figure 4 Comparison of long-cycle performance and single-cycle performance of ordinary Zn / / ordinary Zn and BM-Zn / / BM-Zn symmetrical batteries.

[0025] Figure 5 The graph shows a comparison of the coulombic efficiency and single-cycle performance of ordinary Zn / / Cu and BM-Zn / / Cu half-cells.

[0026] Figure 6 For BM-Zn / / (NH4) x VO3 full cell discharge specific capacity, coulombic efficiency, and specific capacity-voltage diagram.

[0027] Figure 7 For BM-Zn / / (NH4) x VO3 full-cell cyclic voltammetry (CV) performance test chart.

[0028] Figure 8 Voltage display diagram and light bulb test diagram for three BM-Zn full cells connected in series. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below. 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.

[0030] The brass mesh used can be prepared in-house or purchased commercially. In the following specific implementation examples, the brass mesh used was all purchased commercially.

[0031] Example 1

[0032] 1. Preparation of zinc anode materials

[0033] The aqueous zinc-ion battery provided in this embodiment has a negative electrode prepared by the following method:

[0034] S1. Take a piece of 80-mesh brass mesh with dimensions of 5 cm × 5 cm × 100 μm, put it into ultrasonic cleaning to remove surface impurities, take it out and dry the surface moisture, distinguish between the burr-covered and burr-free surfaces, and ensure that the pores on the surface of the brass mesh are evenly distributed, and set it aside for later use.

[0035] Select zinc sheets with a thickness of 20 μm for later use.

[0036] S2. Using a stamping press of the same size as the zinc sheet, stamp out a brass mesh of the same size as the zinc sheet, such as... Figure 1 As shown.

[0037] Zinc sheets and brass mesh are used as negative electrode materials for aqueous zinc-ion batteries, for future reference. Figure 1 As shown.

[0038] 2. Assemble an aqueous zinc-ion battery

[0039] The aqueous zinc-ion battery provided in this embodiment is divided into Zn / / Zn symmetric cells and Zn / / Cu half-cells. Ordinary Zn sheets (20 μm thick), ordinary Cu sheets (15 μm thick), and brass mesh (100 μm thick) are stamped into 12 mm diameter discs for later use.

[0040] (1) Assemble a Zn / / Cu half cell

[0041] Ordinary Zn / / Cu half-cell: Ordinary Zn sheet is used as the zinc negative electrode, and ordinary Cu sheet is used as the positive electrode. The ordinary Zn sheet, glass fiber membrane, and ordinary Cu sheet are assembled and dropped into the electrolyte to prepare an ordinary Zn / / Cu half-cell. The burr-free side of the ordinary Zn sheet faces the glass fiber membrane.

[0042] BM-Zn / / Cu half-cell: The difference between BM-Zn / / Cu half-cell and ordinary Zn / / Cu half-cell is that a brass mesh is placed between the ordinary Zn sheet and the separator. Furthermore, during cell assembly, external pressure is applied to embed the brass mesh into the ordinary Zn sheet, serving as the zinc negative electrode material.

[0043] In this embodiment, the brass mesh is inlaid with a regular Zn sheet as follows: Figure 2As shown in Figure a. Figure a shows the brass mesh and ordinary Zn sheet being fitted together. Figure b shows the two being separated after being fitted together. After applying pressure to fit the brass mesh and ordinary Zn sheet together, there is a clear groove after they are separated.

[0044] Taking the BM-Zn / / Cu half-cell as an example, its assembly process is as follows: ① Place an ordinary Zn sheet into a CR2025 negative electrode shell, with the smooth side facing up; ② Place a brass mesh, with the burr-free side facing up, and then place a glass fiber separator with a diameter of 16 mm; ③ Add 2-3 drops of zinc sulfate solution (electrolyte, concentration of 2 mol / L) to completely wet the glass fiber separator; ④ Place an ordinary Cu sheet as the positive electrode on top of the glass fiber separator, with the smooth side facing down in contact with the glass fiber separator; ⑤ Place a 1.0 mm thick 304 stainless steel gasket and a 1.2 mm thick 304 stainless steel spring sheet, and then close the CR2025 positive electrode shell; ⑥ Use a battery packaging machine to package the battery, thus obtaining one CR2025 standard model specification (diameter 20 mm, height 2.5 mm) BM-Zn / / Cu aqueous zinc-ion half-button battery, i.e., the BM-Zn / / Cu half-cell.

[0045] (2) Assemble a Zn / / Zn symmetric cell

[0046] The Zn / / Zn symmetric cell employs essentially the same assembly process as the Zn / / Cu half-cell described above. The difference lies in the fact that the positive and negative electrodes of the Zn / / Zn symmetric cell are identical. The negative electrode uses either a standard Zn sheet (12 mm in diameter) or a standard Zn sheet with embedded brass mesh (BM-Zn). Finally, the following are sequentially assembled to obtain standard Zn / / standard Zn symmetric cells and BM-Zn / / BM-Zn symmetric cells.

[0047] (3) Assemble Zn / / (NH4) x VO3 full battery

[0048] Zn / / (NH4) x The VO3 full cell uses essentially the same assembly process as the Zn / / Cu half cell described above. The difference lies in: Zn / / (NH4). x The positive electrode of a VO3 full cell uses (NH4). x VO3 electrode (12 mm in diameter). The negative electrode is a standard Zn sheet (BM-Zn) with brass mesh embedded in it (15 mm in diameter). The final assembly yields BM-Zn / / (NH4). x VO3 full battery.

[0049] (NH4) xThe preparation method of VO3 electrode is as follows: First, 0.468 g of NH4VO3 is dissolved in deionized water at 70℃, 0.7612 g of thiourea is added, and dilute sulfuric acid is added dropwise to adjust the pH to 2.0. The mixture is stirred at 90℃ for 2.5 h. Then, it is filtered, washed, and dried at 60℃ for 24 h to obtain (NH4). x VO3 cathode material; then, the cathode material, acetylene black, and PVDF (polyvinylidene fluoride) are mixed in a mass ratio of 7:2:1, and N-methylpyrrolidone is added to form a slurry. This slurry is coated onto carbon paper and dried at 60℃ for 24 h. The slurry coating should have a minimum thickness of 2 mg / cm² after drying. 2 It was cut into electrodes with a diameter of 12 mm to obtain (NH4). x VO3 film.

[0050] The XRD patterns of the brass mesh, ordinary Zn, and ordinary Cu in this embodiment are as follows: Figure 3 As shown, the BM (brass mesh) Zn and Cu used are consistent with those in the standard PDF card, indicating that the sample has high purity.

[0051] 3. Performance Testing

[0052] (1) Zn / / Zn symmetric cell, Zn / / Cu half-cell and Zn / / (NH4) x Cycle performance of VO3 full battery

[0053] The test method for Zn / / Zn symmetric cells is as follows: A constant current of 5 mA / cm² is set in the blue-electricity test system. 2 At current of 1mAh / cm 2 Charge-discharge cycle.

[0054] The test method for Zn / / Cu half-cells is as follows: A constant current of 5 mA / cm² is set in the blue electric current testing system. 2 At current of 1 mAh / cm 2 Discharge, then constant current 5 mA / cm 2 Charge to 1 V under current; perform charge-discharge cycles in this manner.

[0055] Zn / / (NH4) x The testing method for VO3 half-cells is as follows: constant current charging / discharging is performed in the Blue Electric test system at a current density of 5 A / g, with the charging / discharging range set to 0.4~1.8 V, to test the cycle stability of the battery.

[0056] A comparison of constant current charge and discharge of two types of Zn symmetrical batteries, ordinary Zn and BM-Zn, is shown in the figure below. Figure 4As shown in the figures, Figure a presents the long-cycle charts of the two types of batteries. It can be seen that the ordinary Zn / / ordinary Zn symmetrical battery short-circuited at 111 h, while the BM-Zn / / BM-Zn symmetrical battery cycled stably for over 525 h. Enlarged views of the cycle sections in Figures b and c show that both symmetrical batteries cycled normally from 18 to 20 h without short-circuiting; and from 523 to 525 h, the BM-Zn / / BM-Zn symmetrical battery continued to cycle stably, demonstrating excellent cycle stability. Comparing the polarization voltages of the capacity-voltage sections at 50, 100, and 150 cycles, Figures d and e show that the polarization voltage of the BM-Zn symmetrical battery is 60.3 mV, significantly lower than the 76.8 mV of the ordinary Zn symmetrical battery. The high overlap of these three cycles indicates good cycle stability.

[0057] The comparison graph of constant current charge and discharge of two types of Zn / / Cu half-cells, ordinary Zn / / Cu and BM-Zn / / Cu, is shown below. Figure 5 As shown in Figure a, the BM-Zn / / Cu half-cell achieved stable cycling for over 275 cycles under these test conditions, exhibiting an average coulombic efficiency as high as 99.8%. Compared to the ordinary Zn / / Cu half-cell, the BM-Zn / Cu half-cell showed more stable coulombic efficiency in the initial stage. However, the coulombic efficiency of the ordinary Zn / / Cu half-cell began to fluctuate unstablely from the 124th cycle. Figures b and c show the polarization voltages of the ordinary Zn / / Cu and BM-Zn / / Cu half-cells at 1, 50, and 100 cycles, respectively. It can be seen that the BM-Zn / / Cu half-cell has a polarization voltage of 67.9 mV, which is lower than the 76.8 mV of the ordinary Zn / / Cu half-cell, indicating that the BM-Zn / / Cu half-cell has a lower polarization voltage.

[0058] BM-Zn / / (NH4) x The cycle performance comparison chart of VO3 full batteries is shown below. Figure 6 As shown in Figure a, the constant current charge-discharge curve of the full battery at a current density of 5 A / g shows that the battery's initial capacity reaches over 200 mAh / g at a current density of 5 A / g, and the capacity still reaches over 100 mAh / g after 100 cycles, demonstrating a high capacity and indicating that BM-Zn / / (NH4) has a high capacity. x VO3 full-cell capacity decays slowly, resulting in a longer battery life. Figure b shows the specific capacity-voltage diagram. In the battery system using BM-Zn as the negative electrode, the polarization voltage is lower and the capacity plateau is flatter, with a higher curve fit. The stable voltage curve plateau generally reflects the good compatibility of the positive and negative electrodes and the separator. The obvious charge and discharge plateaus indicate that BM-Zn as the negative electrode in this embodiment can significantly improve the long-cycle stability of zinc-ion batteries.

[0059] (2) BM-Zn / / (NH4) x VO3 Full Cell Cyclic Volt-volt-ampere (CV) Performance Test

[0060] BM-Zn / / (NH4) assembled using BM-Zn as the negative electrode x The cyclic voltammetry (CV) performance test results of the VO3 full cell under isothermal conditions at 25°C are as follows: Figure 7 As shown in the figure, the oxidation peak potential is approximately 1.28V, which corresponds to VO. x - The oxidation process; the reduction peak potential is approximately 0.722 V, corresponding to VO x - The reduction process was observed. The measured peaks were symmetrical and sharp, indicating that the BM-Zn negative electrode with added brass mesh has good reversibility.

[0061] Zn / / (NH4) assembled using BM-Zn as the negative electrode x Voltage and application testing of three stacked VO3 full-cell batteries, as follows: Figure 8 As shown in Figure a. Three BM-Zn / / (NH4) atoms can be seen. x The voltage of the stacked VO3 full cells measured with a multimeter was 4.706 V. Figure b shows the three stacked BM-Zn / / (NH4) atoms. x VO3 fully powered LED light strip.

[0062] Example 2

[0063] In this embodiment, the brass mesh used in the zinc anode material for preparing aqueous zinc-ion batteries is 100 mesh.

[0064] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A water-based zinc-ion battery containing a brass mesh, characterized in that, In the structure of the aqueous zinc-ion battery, a brass mesh is embedded on a zinc sheet / foil; the brass mesh is located between the zinc sheet / foil and the separator.

2. The aqueous zinc-ion battery containing brass mesh according to claim 1, characterized in that, The brass mesh has a mesh count of 20-200.

3. The aqueous zinc-ion battery containing brass mesh according to claim 2, characterized in that, The brass mesh has a mesh count of 80-100.

4. The aqueous zinc-ion battery containing brass mesh according to claim 1, characterized in that, The thickness of the brass mesh is 50-200 μm.

5. The aqueous zinc-ion battery containing brass mesh according to claim 4, characterized in that, The thickness of the brass mesh is 100 μm.

6. The aqueous zinc-ion battery containing brass mesh according to claim 1, characterized in that, The thickness of the zinc sheet / zinc foil is 20 μm.

7. The aqueous zinc-ion battery containing brass mesh according to claim 1, characterized in that, The aqueous zinc-ion battery structure also includes a positive electrode material and an electrolyte, the electrolyte being used to completely wet the separator.

8. A method for preparing an aqueous zinc-ion battery containing brass mesh as described in any one of claims 1-7, characterized in that, The zinc sheet / zinc foil and the brass mesh are placed sequentially inside the negative electrode shell; the smooth surface of the zinc sheet / zinc foil faces the brass mesh. Place the diaphragm in the middle, and drip in the electrolyte to completely wet the diaphragm; Insert the positive electrode sheet with the smooth side of the positive electrode sheet facing the separator, place the gasket and spring sheet, snap on the positive electrode shell, and apply pressure to seal the brass mesh onto the zinc sheet / zinc foil to obtain the aqueous zinc-ion battery.

9. A water-based zinc-ion battery anode material, characterized in that, It includes zinc sheets / zinc foil and brass mesh; the brass mesh is embedded in the zinc sheets / zinc foil.

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