A green and controllable method for preparing in-situ polyacrylamide gel electrolyte

Abstract

The present invention discloses a green and speed-controlled method for preparing in-situ polyacrylamide gel electrolyte, which belongs to the technical field of aqueous zinc ion batteries. 2+ and Zn 2+ Combined with Zn-induced acrylamide polymerization, this method can be used to in situ prepare PAM hydrogel electrolytes on the surface of the zinc negative electrode in aqueous zinc-ion batteries. The method provided by this invention allows for in situ preparation of PAM hydrogel electrolytes at room temperature without the need for external energy, initiators, or crosslinkers. The polymerization time significantly decreases with increasing zinc salt solubility and external temperature, and can be further reduced by adding zinc powder. Furthermore, button cells assembled using the in situ PAM hydrogel electrolyte exhibit excellent electrochemical cycling stability.

Description

Technical Field

[0001] The invention belongs to the technical field of aqueous zinc ion batteries, and particularly relates to a green and speed-controllable method for preparing an in-situ polyacrylamide gel electrolyte. Background Art

[0002] Gel electrolytes are a common method for stabilizing the zinc anode-electrolyte interface. Generally, during the zinc plating / stripping process, side reactions on zinc electrodes are primarily initiated by active water molecules in the electrolyte. Furthermore, uncontrollable zinc deposition and nucleation behavior lead to a porous and irregular deposition morphology, further increasing the contact area between the zinc electrode and the active water molecules in the electrolyte and accelerating corrosion of the zinc electrode. Corrosion and byproducts, in turn, cause uneven electric field distribution on the electrode surface, exacerbating the formation of zinc dendrites. Therefore, limiting the contact between water molecules and zinc metal and regulating zinc ion deposition behavior can effectively inhibit side reactions and dendrite formation. Hydrogel electrolytes, due to their low active water content and rich polar functional groups, can effectively inhibit side reactions and zinc dendrite formation. Furthermore, gel electrolytes possess high mechanical strength and processability, which not only prevent electrolyte leakage but also have applications in flexible energy storage.

[0003] However, commonly used gel electrolytes such as polyethylene oxide (PEO), polyvinyl alcohol (PVA), and sodium polyacrylate (PANa) still suffer from low ionic conductivity, poor mechanical strength, and poor salt tolerance. In recent years, polyacrylamide-based gel electrolytes (PAM-modified gel electrolytes) have become a research hotspot. On the one hand, the monomer acrylamide (AM) is highly water-soluble, relatively easy to polymerize, and simple to modify. On the other hand, PAM gel electrolytes contain a large number of polar functional groups that preferentially interact with zinc ions, modifying the zinc ion's solvation structure, reducing the activity of water molecules, and inhibiting side reactions and dendrite formation.

[0004] Traditional polyacrylamide gel synthesis processes require additional energy (heat, ultraviolet light, electricity, etc.), long preparation times (tens of hours), toxic chemical initiators (potassium persulfate (K2S2O8), ammonium persulfate (NH4)2S2O8)), and crosslinkers (N-methylenebisacrylamide, MBAA), resulting in poor controllability of the synthesis rate. Furthermore, a two-step process is typically used: a PAM hydrogel is first prepared, followed by immersion in a zinc salt solution or injection of a zinc salt into the gel to produce a PAM hydrogel electrolyte. This method, which produces gel electrolytes with unquantifiable zinc salt content and is time-consuming, can also cause irreversible deformation of the hydrogel due to swelling. Xu et al. (A mechanically durable hybrid hydrogel electrolyte developed by controllable accelerated polymerization mechanism toward a reliable aqueous zinc-ion battery) achieved room-temperature, second-scale, controllable, one-step preparation of a gel electrolyte by adjusting the zinc sulfate concentration, through the combined action of an initiator and a crosslinker. This method is a time-saving, energy-efficient, and economical method. Furthermore, the addition of montmorillonite nanoparticles (MMT), a modifier, during the preparation process significantly improves the mechanical strength of the gel electrolyte. Polyacrylamide-based gel electrolytes are typically prepared ex situ, sandwiched between electrodes. A poor electrode-electrolyte interface can lead to increased interfacial resistance, zinc dendrite formation, and interfacial side reactions. Based on this, Han et al. (Chemical Welding of the Electrode–Electrolyte Interface by Zn-Metal-Initiated In Situ Gelation for Ultralong-Life Zn-Ion Batteries) recently reported a method for constructing a polyacrylamide gel electrolyte in situ at the zinc anode, leveraging the strong reducing properties of zinc metal. Sulfate radicals generated by the redox reaction between the zinc anode and the initiator K2S2O8 initiate the polymerization of acrylamide monomers, which then polymerize in situ on the zinc electrode to form a gel electrolyte. The in situ gel electrolyte is tightly bonded to the zinc electrode, effectively suppressing zinc dendrites and interfacial side reactions.However, the preparation of polyacrylamide gel electrolytes still requires toxic initiators. To this end, Zeng et al. (In-situ constructing polyacrylamide interphase enables dendrite-free zinc anode in aqueous batteries) placed zinc metal in a mixed solution of zinc sulfate and acrylamide monomer, provided electrons through an external circuit, and formed an in-situ polyacrylamide protective layer on the zinc metal surface. However, the preparation process is complex and requires additional electricity. Therefore, it remains a major challenge to construct a stable and good zinc anode-electrolyte interface by in-situ preparation of PAM gel electrolytes on zinc anodes through green and simple methods. Summary of the Invention

[0005] The purpose of the present invention is to provide a green and controllable method for preparing in-situ polyacrylamide gel electrolyte. 2+ The mixed solution of AM is added dropwise to the surface of the zinc negative electrode. After a period of time, a PAM hydrogel electrolyte is prepared in situ on the surface of the zinc negative electrode. The in situ PAM hydrogel electrolyte provides a good electrode-electrolyte interface. The uniform and compact PAM on the zinc electrode has a good ion path, which promotes the uniform nucleation of the initial zinc and reduces side reactions, thereby enhancing the reversibility of the zinc negative electrode. The preparation method provided by the present invention can prepare the PAM hydrogel electrolyte in situ at room temperature. Without adding external energy, initiator and crosslinking agent, Zn 2+ The hydrated zinc ions in the mixed solution of AM can induce AM to polymerize into PAM ( Figure 1 ), and with the increase of zinc salt solubility and external temperature, the polymerization time is significantly shortened, especially when Zn 2+ When zinc powder is added to the mixed solution of zinc and AM, the mixed solution can be completely gelled within 10 minutes. At the same time, the button battery assembled based on the in-situ PAM gel electrolyte shows good electrochemical cycling stability (the schematic diagram of the in-situ preparation of PAM hydrogel electrolyte on the zinc surface is shown in Figure 2 ).

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a green and controllable method for preparing in-situ polyacrylamide gel electrolyte, comprising the following steps: using Zn 2+ Induce acrylamide polymerization to prepare polyacrylamide gel.

[0008] Among them, Zn 2+ Provided by soluble zinc salts such as zinc sulfate.

[0009] Preferably, the Zn 2+The concentration is 0.1-3mol / L.

[0010] Preferably, during the polymerization reaction, the concentration of acrylamide in the solution system is 1-8 mol / L.

[0011] Preferably, the polymerization temperature is 1-100°C.

[0012] The second technical solution of the present invention is to provide another green and controllable method for preparing in-situ polyacrylamide gel electrolyte, comprising the following steps: using Zn 2+ and Zn induced acrylamide polymerization to prepare polyacrylamide gel.

[0013] Among them, Zn 2+ Provided by soluble zinc salts such as zinc sulfate.

[0014] Preferably, the Zn 2+ The concentration is 0.1-3mol / L.

[0015] Preferably, during the polymerization reaction, the concentration of acrylamide in the solution system is 1-8 mol / L.

[0016] Preferably, the polymerization temperature is 1-100°C.

[0017] Preferably, the molar ratio of Zn to acrylamide is (0.01-0.3):1.

[0018] The present invention adjusts Zn 2+ The polymerization rate of polyacrylamide gel can be controlled by the concentration of Zn, the amount of Zn added and the polymerization temperature.

[0019] The third technical solution of the present invention: provides an application of a green and controllable method for preparing in-situ polyacrylamide gel electrolyte based on the first technical solution in aqueous zinc ion batteries.

[0020] Preferably, the use of Zn-containing 2+ A solution system of polyacrylamide and acrylamide was used to in situ construct a polyacrylamide gel electrolyte on the surface of the zinc negative electrode.

[0021] The beneficial technical effects of the present invention are as follows:

[0022] This paper proposes a green and controllable in situ synthesis strategy for polyacrylamide. At room temperature, without the addition of energy, initiators, or crosslinkers, hydrated zinc ions in a mixed solution of ZnSO4 and acrylamide can induce the polymerization of AM into PAM at a controllable rate. Based on this strategy, a PAM hydrogel electrolyte was prepared in situ on the surface of a zinc anode. This in situ PAM hydrogel electrolyte provides a favorable electrode-electrolyte interface, effectively suppressing zinc dendrites and side reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of zinc sulfate-induced polymerization of AM into PAM.

[0024] Figure 2 Schematic diagram of the in situ preparation of PAM hydrogel electrolyte on zinc surface.

[0025] Figure 3 FTIR spectra, wherein a is the FTIR spectra of the PAM gel electrolyte in Example 1 before and after gelation, and b is the FTIR spectra of commercial AM and the PAM gel electrolytes prepared in Examples 1 and 8.

[0026] Figure 4 Graphs showing the states of the polyacrylamide gel systems in Examples 1-3 at different times.

[0027] Figure 5 Graphs showing the states of the polyacrylamide gel systems in Examples 4-6 at different times.

[0028] Figure 6 1 and 2 are state diagrams of the polyacrylamide gel system in Examples 7-9 at different times, wherein a is the state diagram of the polyacrylamide gel system in Example 7 at different times, b is the state diagram of the polyacrylamide gel system in Example 8 at different times, and c is the state diagram of the polyacrylamide gel system in Example 9 at different times.

[0029] Figure 7 These are the performance test results of the symmetrical button batteries prepared in Examples 10-11. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0031] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0033] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0034] The room temperature in the embodiments of the present invention refers to a temperature of 20±10°C.

[0035] Example 1

[0036] Preparation of polyacrylamide (PAM) gel electrolyte:

[0037] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0038] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0039] (3) The precursor solution was allowed to stand at room temperature for 18 h to obtain a polyacrylamide (PAM) gel electrolyte.

[0040] The FTIR spectra of the PAM gel electrolyte before and after gelation in Example 1 are shown in FIG. Figure 3 Middle a, Figure 3 Middle a shows that before the precursor solution is polymerized, the peaks at 1286, 1438, 1635, 3040, and 3115 cm -1 Under the conditions of 2925cm-1, strong bands from CH bending, CN stretching or CH2 bending, C=C stretching, and vinyl CH2 asymmetric stretching were observed. When the precursor solution was polymerized, the intensity of these bands gradually weakened, and some of them even disappeared. -1 The alkyl CH symmetric stretching band at the position begins to appear. These results strongly prove that the ZnSO4 solution triggers the gradual polymerization of AM monomers into polyacrylamide.

[0041] In addition, to further demonstrate the process, commercial AM and PAM gel electrolytes prepared in Example 1 and Example 8 were subjected to FTIR tests, and the results are shown in Figure 2. Figure 3 As shown in Figure b, the absorption peak of the prepared PAM is very similar to that of commercial AM. -1The absorption band at is caused by NH stretching vibration. The peaks of C=O stretching vibration and NH bending vibration of amide group are located at 1658cm -1 and 1608cm -1 More importantly, none of the prepared samples contained -C=C- (approximately 1000 cm -1 ), but it exists in acrylamide monomer, indicating that ZnSO4 solution triggers the gradual polymerization of AM monomer into polyacrylamide.

[0042] Example 2

[0043] Preparation of polyacrylamide (PAM) gel electrolyte:

[0044] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0045] (2) 2.875 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 1 M ZnSO4);

[0046] (3) The precursor solution was allowed to stand at room temperature for 18 h to obtain a polyacrylamide (PAM) gel electrolyte.

[0047] Example 3

[0048] Preparation of polyacrylamide (PAM) gel electrolyte:

[0049] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0050] (2) 8.625 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 3 M ZnSO4);

[0051] (3) The precursor solution was allowed to stand at room temperature for 12 h to obtain a polyacrylamide (PAM) gel electrolyte.

[0052] The state diagrams of the polyacrylamide gel system in Examples 1-3 at different times are shown in FIG. Figure 4 .

[0053] Example 4

[0054] Preparation of polyacrylamide (PAM) gel electrolyte:

[0055] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0056] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0057] (3) The precursor solution was allowed to stand at 60°C for 4 h to obtain a polyacrylamide (PAM) gel electrolyte.

[0058] Example 5

[0059] Preparation of polyacrylamide (PAM) gel electrolyte:

[0060] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0061] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0062] (3) The precursor solution was allowed to stand at 40°C for 12 h to obtain a polyacrylamide (PAM) gel electrolyte.

[0063] Example 6

[0064] Preparation of polyacrylamide (PAM) gel electrolyte:

[0065] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0066] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0067] (3) The precursor solution was allowed to stand at 20°C for 20 h to obtain a polyacrylamide (PAM) gel electrolyte.

[0068] The state diagrams of the polyacrylamide gel system in Examples 4-6 at different times are shown in FIG. Figure 5 .

[0069] Example 7

[0070] Preparation of polyacrylamide (PAM) gel electrolyte:

[0071] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0072] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0073] (3) 0.05 g of zinc powder was added to the above precursor solution and allowed to stand at room temperature for 10 min to obtain a polyacrylamide (PAM) gel electrolyte.

[0074] Example 8

[0075] Preparation of polyacrylamide (PAM) gel electrolyte:

[0076] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0077] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0078] (3) 0.1 g of zinc powder was added to the above precursor solution and placed at room temperature for 7 min to obtain a polyacrylamide (PAM) gel electrolyte.

[0079] Example 9

[0080] Preparation of polyacrylamide (PAM) gel electrolyte:

[0081] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0082] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0083] (3) 0.2 g of zinc powder was added to the above precursor solution and placed at room temperature for 7 min to obtain a polyacrylamide (PAM) gel electrolyte.

[0084] The state diagrams of the polyacrylamide gel system in Examples 7-9 at different times are shown in FIG. Figure 6, wherein a is a state diagram of the polyacrylamide gel system at different times in Example 7, b is a state diagram of the polyacrylamide gel system at different times in Example 8, and c is a state diagram of the polyacrylamide gel system at different times in Example 9.

[0085] Example 10

[0086] Preparation of in-situ PAM gel electrolyte aqueous zinc ion symmetric button cell:

[0087] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0088] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0089] (3) Cutting a commercial zinc metal foil with a thickness of 0.1 mm into discs with a diameter of 12 mm, then ultrasonically cleaning it with anhydrous ethanol for 10 min and drying it at room temperature to obtain a clean zinc metal electrode;

[0090] (4) Assembly of aqueous zinc ion symmetric button cell (CR2032 type) with in situ PAM gel electrolyte: 120 μL of precursor solution (5MAM+2M ZnSO4) was added dropwise to the zinc metal electrode, and the mixture was allowed to stand for 1 hour until the mixed solution turned into a gel-like liquid. Then, a zinc metal electrode of the same size was placed on top of the gel-like liquid to form a sandwich structure. The mixture was allowed to stand for 1 hour until the gel-like liquid turned into an in situ PAM gel electrolyte (In situ PAM). After that, the gasket and the shrapnel were placed in sequence, and finally the negative electrode shell was buckled on. The battery was packaged using a battery packaging machine to obtain an aqueous zinc ion symmetric button cell, which was marked as a Zn / In situ PAM / Zn symmetric battery.

[0091] Example 11

[0092] Preparation of symmetrical button cells with ex-situ PAM gel electrolyte aqueous zinc ion symmetric batteries:

[0093] (1) Add 3.55 g of acrylamide (AM) to 10 mL of deionized water and stir to dissolve to obtain a 5 mol / L AM aqueous solution;

[0094] (2) 5.75 g of zinc sulfate heptahydrate (ZnSO4·7H2O) was uniformly dispersed in 10 mL of 5MAM aqueous solution to obtain a precursor solution (5MAM + 2 M ZnSO4);

[0095] (3) The precursor solution was injected into a polytetrafluoroethylene mold with a diameter of 16 mm and a depth of 1 mm and placed at room temperature for 18 h to obtain an ex situ PAM gel electrolyte (Ex situ PAM);

[0096] (4) Cutting a commercial zinc metal foil with a thickness of 0.1 mm into discs with a diameter of 12 mm, then ultrasonically cleaning the discs with anhydrous ethanol for 10 min and drying them at room temperature to obtain clean zinc metal electrodes;

[0097] (5) Assembly of an aqueous zinc ion symmetric button cell (CR2032 type) with an ex-situ PAM gel electrolyte: Place the zinc metal electrode in the negative electrode shell, place the pre-prepared PAM gel on the zinc metal electrode, squeeze out the bubbles between the electrode and the PAM gel, and make the electrode and the PAM gel in close contact. Then, place a zinc metal electrode of the same size on top of the PAM gel to form a sandwich structure. Then, place the gasket and the spring in turn, buckle the negative electrode shell, and finally use a battery packaging machine to package the battery to obtain an aqueous zinc ion symmetric button cell, which is marked as a Zn / Ex situPAM / Zn symmetric battery.

[0098] Test Example 1

[0099] The aqueous zinc ion symmetrical button cells prepared in Examples 10-11 were subjected to constant current charge and discharge tests:

[0100] At a current density of 1 mA·cm -2 , surface capacity is 1mAh·cm -2 The aqueous zinc ion symmetric button cells (Zn / In situ PAM / Zn and Zn / Ex situ PAM / Zn) prepared in Example 10 and Example 11 were subjected to constant current charge and discharge tests. The results are shown in FIG. Figure 7 As shown ( Figure 7 In situ PAM represents Zn / In situ PAM / Zn, and Ex situ PAM represents Zn / Exsitu PAM / Zn). Figure 7 It can be seen that the Zn / Ex situ PAM / Zn symmetrical button cell experienced a short circuit phenomenon after about 1460h of cycling (see Figure 7 The voltage polarization of the Zn / In situ PAM / Zn symmetric button cell always maintains a lower voltage polarization than that of the Zn / Ex situ PAM / Zn symmetric cell, and the reversible plating and stripping time reaches 3800h. Figure 7) It can be seen that there is no soft short circuit in the in-situ PAM symmetric battery during cycling, which indicates that the in-situ PAM provides a good electrode-electrolyte interface, which largely suppresses the side reactions during battery cycling and improves the battery's cycling stability.

[0101] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A green and controllable method for preparing in-situ polyacrylamide gel electrolyte, characterized in that: The steps are: using only ZnSO4 to induce acrylamide polymerization to prepare polyacrylamide gel; The concentration of ZnSO4 is 1-3 mol / L; The concentration of acrylamide in the solution system is 1-8 mol / L; The temperature during the polymerization is 20±10° C., and no external energy is added.

2. A green and controllable method for preparing in-situ polyacrylamide gel electrolyte, characterized in that: The steps are: using ZnSO4 and Zn to induce acrylamide polymerization to prepare polyacrylamide gel; The concentration of ZnSO4 is 1-3 mol / L; The concentration of acrylamide in the solution system is 1-8 mol / L; The temperature during the polymerization is 20±10° C., and no external energy is added.

3. The green and controllable method for preparing in-situ polyacrylamide gel electrolyte according to claim 2, characterized in that: The molar ratio of the Zn to the acrylamide is (0.01-0.3):

1.

4. Application of the green and controllable rate preparation method of in-situ polyacrylamide gel electrolyte according to claim 1 in aqueous zinc ion batteries.

5. The use according to claim 4, characterized in that A polyacrylamide gel electrolyte was in situ constructed on the surface of the zinc negative electrode using a solution system containing ZnSO4 and acrylamide.

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