Zinc ion manganese-based thick electrode preparation method based on laser micro-nano regulation and battery

Abstract

The invention discloses a zinc ion manganese-based thick electrode preparation method based on laser micro-nano regulation and a battery, and the method comprises the steps: obtaining an electrode slurry containing alpha-MnO2 powder, coating the slurry on the surface of a graphite current collector for many times, placing the graphite current collector in a vacuum drying oven of 60 DEG C for drying after each coating, and accumulating the drying time for 24 hours to obtain the zinc ion manganese-based thick electrode. The surface loading capacity of the initial thick manganese dioxide electrode is 10mg cm <-2 >, and the thickness of the initial thick manganese dioxide electrode is 200mu m; a femtosecond laser is controlled through numerical values of a computer to accurately scan and machine the initial manganese dioxide thick electrode on the surface of the thick electrode and in the full thickness direction, a preset structured pattern is constructed, and finally the laser structured manganese dioxide thick electrode is prepared; according to the electrode with the thickness of 200 microns, the high area specific capacity of 1 mAh cm <-2 > under 0.1 A g <-1 > is kept, high-magnification output of 0.5 mAh cm <-2 > under 1A g <-1 > is achieved, and the performance bottleneck of a traditional thick electrode is broken through.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage device methods, and particularly relates to a method for preparing zinc-manganese-based thick electrodes and batteries based on laser micro-nano control. Background Technology

[0002] Electrochemical energy storage technology, as a core support for new power systems, is rapidly developing towards higher safety, higher energy density, lower cost, and longer lifespan. Aqueous zinc-ion batteries, with their unique advantages, have become one of the current research hotspots in the energy storage field: on the one hand, aqueous electrolytes are non-flammable and have no explosion risk, fundamentally solving the safety hazards of traditional lithium-ion batteries; on the other hand, zinc resources are abundant in the Earth's crust, and zinc metal anodes have a theoretically high capacity (820 mAh g / g). -1 The low deposition / dissolution potential (-0.76V vs standard hydrogen electrode) and low cost significantly lower the barrier to large-scale application of batteries. Manganese dioxide (MnO2) also possesses a high theoretical specific capacity (308mAh g / g). -1 With its excellent chemical stability and abundant resources, it has become one of the preferred cathode materials for zinc-ion batteries.

[0003] To further improve the energy density of zinc-ion batteries, thick electrodes (typically defined as those with an areal loading ≥ 10 mg / cm²) are fabricated. -2 This is a direct and effective technical approach; however, the application of traditional thick electrodes faces three major technological bottlenecks:

[0004] Low ion transport efficiency: The large thickness of the active material layer inside the thick electrode results in a long ion migration path, which leads to a significant reduction in the utilization rate of the active material during high-rate charge and discharge.

[0005] High electronic conduction resistance: MnO2 itself is a semiconductor material with poor electronic conductivity. The contact interface between the active material and the conductive agent and current collector in the thick electrode is limited, which further aggravates the electronic conduction barrier.

[0006] Insufficient mechanical stability: During charge-discharge cycles, MnO2 reacts with Zn. 2+ Intercalation / deintercalation reactions are accompanied by significant volume expansion and contraction. Stress concentration is easily generated inside thick electrodes, leading to structural damage such as cracks and peeling, resulting in rapid capacity decay of the battery.

[0007] To address the aforementioned issues, it is necessary to research a method for preparing zinc-manganese-based thick electrodes and batteries based on laser micro-nano control, which utilizes laser processing technology to solve the mass transfer bottleneck problem of thick electrodes. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing zinc-ion manganese-based thick electrodes and batteries based on laser micro-nano control. By precisely constructing structured patterns with femtosecond lasers, the ion transport efficiency, electronic conduction performance and mechanical stability of the thick electrodes are simultaneously optimized without introducing additional materials, thereby improving the rate performance and cycle life of zinc-ion batteries.

[0009] To address the problems existing in the background art, the present invention adopts the following technical solution:

[0010] A method for fabricating zinc-manganese-based thick electrodes based on laser micro / nano modulation, the method comprising the following steps:

[0011] An electrode slurry containing α-MnO2 powder was obtained and coated multiple times onto the surface of a graphite current collector. After each coating, the slurry was dried in a vacuum drying oven at 60°C for a total drying time of 24 hours, resulting in an electrode with an area loading of 10 mg / cm². -2 An initial manganese dioxide thick electrode with a thickness of 200 μm;

[0012] By using a computer numerically controlled femtosecond laser to precisely scan and process the initial manganese dioxide thick electrode on the surface and throughout its thickness, a pre-defined structured pattern is constructed, ultimately resulting in a laser-structured manganese dioxide thick electrode.

[0013] Furthermore, the structured pattern can be a trench structure with a width of 50 μm, a spacing of 300 μm between trenches, and the trenches penetrating the entire thickness of the electrode.

[0014] Furthermore, the structured pattern can be a mesh structure with a width of 50 μm, a mesh spacing of 600 μm, and the mesh structure penetrates the entire thickness of the electrode.

[0015] Furthermore, the structured pattern can be a dot matrix structure with a dot spacing of 140 μm and a dot diameter of 50 μm, and the dot matrix structure penetrates the entire thickness of the electrode.

[0016] Furthermore, the output parameters of the femtosecond laser are precisely controlled according to the structured pattern type:

[0017] When constructing a grooved or mesh structure, the output power is 0.9W, the repetition frequency is 50kHz, the spot diameter is 30μm, the scanning speed is 200mm s-1, and the number of scans is 15.

[0018] When constructing the dot matrix structure, the output power was adjusted to 0.44W, the dot engraving time was 3ms, the repetition frequency was 50kHz, the spot diameter was 30μm, the scanning speed was 200mm s⁻¹, and the number of scans was 15.

[0019] Furthermore, the α-MnO2 powder has a 2×2 and 1×1 tunnel-like crystal structure and abundant electrochemical activity.

[0020] Furthermore, the method for obtaining electrode slurry containing α-MnO2 powder is as follows:

[0021] At a mass ratio of 7:2:1, α-MnO2 powder, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are dispersed in N-methylpyrrolidone (NMP) solvent and stirred at high speed to form a uniform and stable electrode slurry.

[0022] An aqueous zinc-ion battery includes a zinc-manganese-based thick electrode positive electrode, a zinc metal foil negative electrode, a glass fiber porous separator, and a 2M zinc sulfate aqueous solution electrolyte. The components are assembled into a button cell in the order of positive electrode-separator-negative electrode, and the battery's operating voltage range is 1-1.8V.

[0023] The beneficial technical effects of this invention are as follows:

[0024] 1. This invention synergistically improves energy density and rate performance, maintaining 0.1Ag even with a 200μm thick electrode. -1 1mAh cm -2 High area specific capacity, and also achieves 1Ag -1 0.5mAh cm -2 High-rate output, breaking through the performance bottleneck of traditional thick electrodes;

[0025] 2. This invention achieves precise performance matching of topological patterns. By systematically comparing trench-type, lattice-type, and mesh-type structured patterns, it clarifies that the trench-type continuous channel structure is the optimal choice, with a 1Ag... -1 0.5mAh cm -2 The area-to-capacity ratio is higher than that of the dot matrix type (0.33mAh cm⁻¹). -2 Mesh type (0.39mAh cm) -2 These improvements of 51.5% and 28.2% respectively have resolved the blind spots in the selection of structured patterns and ensured the maximization of electrode performance.

[0026] 3. This invention achieves the optimal combination of structural parameters. Under the fixed conditions of 200μm electrode thickness, 30μm channel width, and 200μm channel depth, a trench spacing of 300μm is determined as the performance balance point. This avoids the problems of electrode cracking and excessive loss of active material under a 200μm spacing, and overcomes the defects of excessive unstructured area and limited performance improvement under a 400μm spacing, thus achieving the optimal overall electrode performance. Attached Figure Description

[0027] Figure 1(a) is a surface SEM image of the trench structure manganese dioxide thick electrode in Embodiment 1 of the present invention;

[0028] Figure 1(b) is a cross-sectional SEM image of the trench structure manganese dioxide thick electrode in Embodiment 1 of the present invention;

[0029] Figure 1(c) is a surface SEM image of the thick manganese dioxide electrode with a mesh structure in Embodiment 1 of the present invention;

[0030] Figure 1(d) is a cross-sectional SEM image of the thick manganese dioxide electrode with a mesh structure in Embodiment 1 of the present invention;

[0031] Figure 1(e) is a surface SEM image of the lattice structure manganese dioxide thick electrode in Embodiment 1 of the present invention;

[0032] Figure 1(f) is a cross-sectional SEM image of the lattice structure manganese dioxide thick electrode in Embodiment 1 of the present invention;

[0033] Figure 1(g) is a surface SEM image of the manganese dioxide thick electrode with a 200 μm spacing trench structure in Example 1 of the present invention;

[0034] Figure 1(h) is a surface SEM image of the thick manganese dioxide electrode with a 400 μm spacing trench structure in Embodiment 1 of the present invention;

[0035] Figure 2(a) is a cross-sectional SEM image of the electrode in Comparative Example 1 of the present invention;

[0036] Figure 2(b) is a cross-sectional SEM image of the electrode in Comparative Example 2 of the present invention;

[0037] Figure 3(a) shows the mass-normalized specific capacity cycling performance of different electrodes;

[0038] Figure 3(b) shows the area-normalized specific capacity cycling performance of different electrodes;

[0039] Figure 3(c) shows the area-normalized specific capacity cycling performance of electrodes with different trench structures;

[0040] Wherein, Unstructured represents an unstructured manganese dioxide thick electrode; L300 represents a manganese dioxide thick electrode with a trench spacing of 300 μm; Grid represents a mesh structure manganese dioxide thick electrode; Spot represents a lattice structure manganese dioxide thick electrode; Thin represents an unstructured manganese dioxide thin electrode; L200 represents a manganese dioxide thick electrode with a trench spacing of 200 μm; and L400 represents a manganese dioxide thick electrode with a trench spacing of 400 μm. Detailed Implementation

[0041] The following description, in conjunction with the accompanying drawings, provides a clearer and more complete account of the method for fabricating zinc-manganese-based thick electrodes and batteries based on laser micro-nano control, and further details the specific embodiments and comparative examples provided below:

[0042] All raw materials, reagents, and equipment used in this embodiment are commercially available products: manganese sulfate monohydrate and potassium permanganate were purchased from Sinopharm Chemical Reagent Co., Ltd.; conductive agent Super P, binder PVDF, N-methylpyrrolidone (NMP), graphite current collector, and button battery casing (CR2025) were purchased from Dongguan Kelude New Energy Technology Co., Ltd.; the femtosecond laser model was FemotoYL-40.

[0043] Example 1: Fabrication of a trench-structured manganese dioxide thick electrode

[0044] (1) Preparation of α-MnO2 powder: Weigh 0.76g of manganese sulfate monohydrate and 0.47g of potassium permanganate, add 80mL of deionized water, and stir magnetically for 30 minutes until a uniform suspension is formed; transfer the suspension to a 100mL polytetrafluoroethylene-lined autoclave and react at 160℃ for 12 hours; after the reaction, filter the product, wash it 5 times alternately with deionized water and anhydrous ethanol, and dry it under vacuum at 80℃ for 12 hours to obtain α-MnO2 powder;

[0045] (2) Initial Thick Electrode Preparation: 0.7 g of α-MnO2 powder, 0.2 g of conductive agent Super P, and 0.1 g of binder PVDF were weighed according to a mass ratio of 7:2:1. 5 mL of N-methylpyrrolidone (NMP) solvent was added, and the mixture was ground and stirred in a mortar for 2 hours to prepare a uniform slurry. The slurry was then coated onto the surface of a graphite current collector using a doctor blade coating method, with a coating thickness controlled at 200 μm. After coating, the material was vacuum dried at 60 °C for a cumulative drying time of 24 hours, yielding an area loading of 10 mg / cm². -2 The initial thick electrode;

[0046] (3) Laser structuring: The initial thick electrode is fixed on the laser processing platform, and the femtosecond laser parameters are set as follows: output power 0.9W, repetition rate 50kHz, spot diameter 30μm, and scanning speed 200mm / s. -1 The scanning was performed 15 times. The groove pattern was set by computer programming. The groove width was 50μm, the spacing was 300μm, and the depth was 200μm (through the electrode). The laser was started to complete the structured processing and a grooved manganese dioxide thick electrode was obtained.

[0047] Example 2: Preparation of a thick manganese dioxide electrode with a mesh structure

[0048] The difference between this embodiment and embodiment 1 is that the laser-structured pattern is a mesh structure. In step (3), the laser processing parameters are adjusted as follows: the mesh spacing is 600 μm, and the groove width, depth and laser output parameters are the same as in embodiment 1. The remaining steps, raw material ratios and process parameters are the same as in embodiment 1, and a mesh structure manganese dioxide thick electrode is obtained.

[0049] Example 3: Fabrication of a lattice-structured manganese dioxide thick electrode

[0050] The difference between this embodiment and embodiment 1 is that the laser-structured pattern is a dot matrix structure. In step (3), the laser output parameters are adjusted to: output power 0.44W, dot engraving time 3ms, and spot diameter 30μm; the dot matrix pattern parameters are: dot spacing 140μm, dot diameter 50μm, and depth 200μm; the remaining steps, raw material ratios and process parameters are the same as in embodiment 1, and a dot matrix structure manganese dioxide thick electrode is obtained.

[0051] Example 4: Fabrication of thick manganese dioxide electrodes with different trench structures

[0052] The difference between this embodiment and embodiment 1 is that the spacing of the groove structure is different. In step (3), the laser processing parameters are adjusted to: the groove spacing is 200μm and 400μm, and the groove width, depth and laser output parameters are the same as in embodiment 1. The remaining steps, raw material ratio and process parameters are the same as in embodiment 1, and manganese dioxide thick electrodes with different groove structures are obtained.

[0053] Figures 1(a), (c), and (e) clearly show the surface morphology of the trench, mesh, and lattice structures of the thick electrodes. Figures 1(b), (d), and (f) show that the laser structuring depth of the three types of structured thick electrodes reaches the electrode thickness. Figures 1(g) and (h) show the trench structure thick electrodes with spacing of 200 μm and 400 μm, respectively.

[0054] Comparative Example 1: Preparation of Unstructured Manganese Dioxide Thick Electrode

[0055] An initial manganese dioxide thick electrode (area loading 10 mg cm⁻¹) was prepared according to steps (1) and (2) of Example 1. -2 The manganese dioxide thick electrode (with a thickness of 200 μm) was directly used as the electrode sample of Comparative Example 1 without laser structuring. The resulting manganese dioxide thick electrode is shown in Figure 2(a). It can be observed from the figure that the initial thickness of the thick electrode is 200 μm.

[0056] Comparative Example 2: Preparation of Unstructured Manganese Dioxide Thin Electrode

[0057] Electrode paste was prepared according to the raw material ratio of Example 1 (α-MnO2:Super P:PVDF = 7:2:1), coated onto the surface of graphite current collector in one step, with the coating thickness controlled at 30 μm, and vacuum dried at 60°C for 12 hours to obtain an area loading of approximately 2 mg / cm². -2 The unstructured thin electrode, as the electrode sample of Comparative Example 2, is shown in Figure 2(b), and the thickness of the thin electrode is 30 μm.

[0058] The electrode samples from Examples 1-4 and Comparative Examples 1 and 2 were assembled into CR2025 button batteries with zinc foil negative electrodes, glass fiber separators, and 2MZnSO4 aqueous electrolytes, respectively. Rate performance was tested using a Blue Electric CT2001A battery testing system under the following conditions: current density 0.1-2 Ag. -1 Voltage range 1-1.8V.

[0059] The test results are shown in Figure 3. At 0.1 Ag -1 At a current density of 200 μm, the areal specific capacity of an initial thick electrode can reach 1 mAh cm⁻¹. -2 This is significantly higher than the 0.3 mAh cm⁻¹ of a 30 μm thin electrode. -2 This demonstrates the significant advantage of thick electrodes in increasing energy density per unit area. However, when the current density is increased to 2Ag... -1 At high rate conditions, the specific capacity of a thick electrode is actually lower than that of a thin electrode. The essence of this contradiction is that although a thick electrode increases the area specific capacity by increasing the surface loading of active material, it also increases the tortuosity of the electrode, which hinders ion diffusion and forms a significant ion concentration gradient between the electrode surface and the interior, increasing concentration polarization and electrochemical polarization, ultimately leading to a decrease in rate performance.

[0060] from Figure 3(a) , 3(b) It is clear that regardless of the topological pattern used, femtosecond laser structuring significantly improves the rate performance of thick electrodes. This is due to the dual effect of the high aspect ratio (depth / width ≈ 7) channels constructed by the laser: on the one hand, it increases the active surface area of ​​the electrode, improving its polarization characteristics; on the other hand, the vertical channels directly shorten the ion transport path, reducing electrode tortuosity. The core constraint on ion transport in thick electrodes is concentration polarization-driven diffusion control, and its diffusion efficiency follows a modified Fick's law.

[0061]

[0062] Where J is the ion flux, D is the diffusion coefficient, ΔC is the concentration gradient, τ is the electrode tortuosity, and L is the diffusion path length. For thick electrodes (L = 200 μm), laser-structured ion diffusion channels can simultaneously optimize τ and L. Taking a trench structure as an example, continuous channels shorten the diffusion path L from 200 μm (through the electrode thickness) to half the trench spacing; a 300 μm spacing corresponds to L = 150 μm (since the vertical trenches act as ion highways, electrolyte and ions can reach any depth of the electrode almost without resistance along the trenches, thus L is converted into the lateral diffusion distance). For ideal parallel straight channels, τ = 1; for practical porous electrodes, τ is typically between 3 and 10. Therefore, laser-structured electrodes have a faster ion transport rate.

[0063] Further comparison of the performance differences of different structured patterns revealed that the trench structure exhibited the best electrochemical performance: at 1 Ag... -1 At high current density, it has 0.5mAh cm⁻¹ -2 The areal specific capacity is higher than that of the unstructured thick electrode (0.14 mAh cm⁻¹). -2 More than 3 times that of the dot matrix type (0.33mAh cm⁻¹), and greater than that of the dot matrix type (0.33mAh cm⁻¹). -2 ) and mesh type (0.39mAh cm -2 Compared to lattice-type one-dimensional discrete structures, the continuous channels of trench structures provide a larger specific surface area, improving the effective contact and reaction interface between the electrode and electrolyte, and significantly improving electrode polarization. Compared to complex structures such as meshes, trench structures have more stable mechanical properties, avoiding stress concentration at mesh corners and minimizing the weakening of the overall mechanical strength of the electrode. Using the "diffusion time constant" for quantitative comparison, the diffusion time constant t, derived from Fick's second law, approximately satisfies:

[0064]

[0065] Where L is the diffusion path length, D eff D is the effective diffusion coefficient. Under the same material and electrode thickness, D eff Similarly, under the same active material loss, closed cell patterns such as mesh have larger cell sizes and diffusion lengths greater than those of trenches. Therefore, given the active material loss constraint, a continuous, unbranched one-dimensional channel array (i.e., parallel trenches) perpendicular to the current collector can minimize the maximum Euclidean distance from any point inside the electrode to the nearest channel inlet, thus theoretically minimizing diffusion polarization.

[0066] To determine the optimal range of trench structure parameters, we fixed the thickness of the thick electrode at 200 μm and investigated the effects of different trench spacings: The L200 electrode with a spacing of 200 μm had too small a spacing and too high channel density, which weakened the mechanical strength of the electrode. As can be seen from Figure 1(g), the electrode developed slight cracks, resulting in decreased structural stability and excessive ablation of material, leading to increased loss of active material and thus a decrease in battery specific capacity. The L400 electrode with a spacing of 400 μm had too large a spacing, resulting in an excessively large unstructured area (over 90%), similar to the unstructured thick electrode, and thus had limited effect on improving battery performance.

[0067] Based on the above results, the trench structure design with a spacing of 300 μm in the 200 μm thick manganese dioxide electrode achieves the optimal balance of "energy density-transmission efficiency-mechanical stability" and has the best electrochemical performance.

[0068] Because the pulse width of a femtosecond laser is much shorter than the thermal diffusion time of the electrode materials (including α-MnO2, the conductive agent Super P, and the binder PVDF), the laser energy can be concentrated on the electrode surface and shallow regions within an extremely short time (<100 fs), causing the material molecules or atoms to directly absorb energy and undergo "photoionization," forming plasma. During this process, the energy does not have time to diffuse to the surroundings, thus avoiding the "heat-affected zone (HAZ)" common in traditional laser processing. This effectively protects the integrity of the α-MnO2 crystal structure and prevents electrochemical activity decay caused by crystal phase transitions; simultaneously, it avoids the carbonization failure of the binder PVDF due to high temperatures, ensuring the stability of the internal structure of the electrode.

[0069] By precisely controlling the output parameters (such as power, repetition rate, and scanning speed) and trajectory of a femtosecond laser through computer programming, pre-defined topologies (such as trenches, meshes, or lattices) can be accurately constructed within a thick manganese dioxide electrode. These structures, acting as rapid transport channels, effectively shorten ion transport paths, accelerate the electrolyte wetting process, reduce ion transport resistance, and improve transport efficiency. Simultaneously, the constructed structures provide a buffer for the volume expansion of the electrode during cycling, helping to mitigate internal stress concentration and thus enhancing the mechanical stability of the thick electrode.

[0070] In summary, this invention effectively solves the technical bottleneck of zinc-ion manganese-based thick cathodes through laser structuring, and significantly improves the rate performance and cycle stability of the battery while maintaining high energy density.

[0071] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a zinc ion manganese-based thick electrode based on laser micro-nano regulation, characterized in that, The method comprises the following steps: An electrode slurry containing α-MnO2 powder was prepared, and the slurry was coated on the surface of a graphite current collector multiple times, and dried in a vacuum drying oven at 60°C after each coating. The total drying time was 24 hours, and an initial manganese dioxide thick electrode with a surface loading of 10 mg cm -2 and a thickness of 200 μm was prepared. The method comprises the following steps:

2. The method for preparing zinc ion manganese-based thick electrode based on laser micro-nano regulation and control according to claim 1, characterized in that, The structured pattern can be a groove structure, the width of the groove structure is 50 μm, the interval between grooves is 300 μm, and the groove structure penetrates the full thickness of the electrode. 3.The method of claim 1, wherein the method further comprises the step of: The structured pattern can be a mesh structure, the width of the mesh structure is 50 μm, the interval of the mesh structure is 600 μm, and the mesh structure penetrates the full thickness of the electrode. ​ 4.The method of claim 1, wherein the method further comprises the step of: The structured pattern can be a dot array structure, the interval of the dot array structure is 140 μm, the dot diameter is 50 μm, and the dot array structure penetrates the full thickness of the electrode. ​ 5. The method for preparing zinc ion manganese-based thick electrode based on laser micro-nano regulation and control according to claim 1, characterized in that, The output parameters of the femtosecond laser are precisely controlled according to the type of the structured pattern: When the groove structure or the mesh structure is constructed, the output power is 0.9 W, the repetition frequency is 50 kHz, the spot diameter is 30 μm, the scanning speed is 200 mm s-1, and the scanning number is 15 times. When the dot array structure is constructed, the output power is adjusted to 0.44 W, the dot carving time is 3 ms, the repetition frequency is 50 kHz, the spot diameter is 30 μm, the scanning speed is 200 mm s-1, and the scanning number is 15 times.

6. The method for preparing zinc ion manganese-based thick electrode based on laser micro-nano regulation and control according to claim 1, characterized in that, The α-MnO2 powder has 2×2 and 1×1 tunnel-like crystal structures and rich electrochemical activity.

7. The method for preparing zinc ion manganese-based thick electrode based on laser micro-nano regulation and control according to claim 1, characterized in that, The method for obtaining the electrode slurry containing the α-MnO2 powder comprises the following steps: According to the mass ratio of 7:2:1, the α-MnO2 powder, the conductive agent Super P and the binder polyvinylidene fluoride (PVDF) are dispersed in the N-methyl pyrrolidone (NMP) solvent, and then high-speed stirring is performed to form a uniform and stable electrode slurry.

8. An aqueous zinc-ion battery, characterized in that, The zinc ion manganese-based thick electrode anode, the zinc metal foil negative electrode, the glass fiber porous diaphragm and the 2M zinc sulfate aqueous electrolyte are assembled into a button cell in the order of anode-diaphragm-negative electrode, and the working voltage range of the cell is 1-1.8 V.

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