Hydrogel electrolyte modified by strong polar group as well as preparation method and application of hydrogel electrolyte

Abstract

The invention belongs to the technical field of electrochemistry, and particularly relates to a strong polar group modified hydrogel electrolyte as well as a preparation method and application thereof. The preparation method of the hydrogel electrolyte comprises the following steps: modifying dimethylaminoethyl methacrylate with a strong polar group to obtain dimethylaminoethyl methacrylate modified by the strong polar group; the preparation method comprises the following steps: mixing dimethylaminoethyl methacrylate modified by a strong polar group, acrylamide and zinc salt, adding a cross-linking agent and an initiator to obtain a mixed solution, and performing ultraviolet irradiation on the mixed solution to obtain the water-soluble polymer. The strong polar group is any one of a bromomethyl trifluoroborate group, an iodomethyl trifluoroborate group, a boron trifluoride methyl ether group and an ethyl trifluoroborate group. According to the hydrogel electrolyte, the shuttle effect of polyiodide is effectively inhibited, construction of a stable and efficient ion migration channel is facilitated, zinc is guided to preferentially grow along the crystal face, and growth of zinc dendrites is effectively inhibited.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical technology, and in particular relates to a hydrogel electrolyte modified with a strong polar group, and a preparation method and application thereof. Background Art

[0002] In recent years, aqueous zinc-ion batteries (Zn-I)—such as zinc-manganese oxide batteries, zinc-air batteries, and zinc-halogen batteries—have been considered one of the most promising battery types due to their high theoretical specific capacity of 820 mAh / g, low electrode potential of -0.76 V, excellent air stability, and abundant zinc resources. Among various aqueous Zn-I batteries, Zn-I batteries stand out due to the unique properties of iodine, which offers advantages such as low cost and extremely low water solubility. More importantly, iodine's rich valence states give it exceptional theoretical multi-electron conversion potential. Consequently, Zn-I batteries can deliver impressive potential outputs while also possessing high theoretical capacity. Compared to other Zn-halogen batteries, such as Zn-bromine / Zn-chlorine batteries, the solid-state iodine cathode in Zn-I batteries offers greater operability, milder reaction conditions, and significantly reduced corrosiveness. Therefore, Zn-I batteries offer unique advantages among halogen cathode materials and have become a key research area.

[0003] However, zinc-iodine batteries still face a series of key problems. One of them is the poor conductivity of the iodine positive electrode and the polyiodide. Iodine itself is thermodynamically unstable, and the polyiodide formed during the battery cycle, such as I 3- and I 5- It will dissolve and trigger the shuttle effect; secondly, when the zinc-iodine battery is used as the negative electrode, side reactions such as hydrogen evolution reaction and corrosion are very likely to occur. At the same time, the surface current density is unevenly distributed, resulting in uneven zinc deposition during the reduction process, and ultimately producing zinc dendrites.

[0004] Hydrogel electrolytes exhibit excellent wettability, flexibility, and thermal stability. Compared to liquid electrolytes, they significantly reduce the shuttle effect and dendrite growth, making them an ideal alternative. Currently, commonly used hydrogel electrolytes include gelatin, sulfobetaine methacrylate, and sodium carboxymethyl cellulose. However, in zinc-iodine batteries, these electrolytes exhibit significant problems such as the shuttle effect and dendrite growth, which can affect electrical performance and reduce discharge capacity. Summary of the Invention

[0005] In order to solve the problems of shuttle effect of polyiodide and zinc dendrite in zinc-iodine batteries in the prior art, the present invention provides a hydrogel electrolyte modified with strong polar groups, and a preparation method and application thereof.

[0006] To achieve the above objectives, the technical solutions of the present invention are specifically as follows.

[0007] A first aspect of the present invention provides a strongly polar group-modified hydrogel electrolyte, wherein the hydrogel electrolyte is prepared by modifying dimethylaminoethyl methacrylate with a strongly polar group to obtain dimethylaminoethyl methacrylate modified with a strongly polar group; mixing the dimethylaminoethyl methacrylate modified with a strongly polar group, acrylamide, and a zinc salt, and adding a crosslinking agent and an initiator to obtain a mixed solution; and subjecting the mixed solution to ultraviolet irradiation to obtain a hydrogel electrolyte; The strong polar group is any one of a bromomethyl trifluoroboron group, an iodomethyl trifluoroboric acid group, a boron trifluoride methyl ether group, and an ethyl trifluoroboric acid group.

[0008] The present invention can effectively inhibit the shuttle effect of polyiodides through the strong electrostatic repulsion between any one of the strong polar groups bromomethyl trifluoroboron group, iodomethyl trifluoroboric acid group, trifluoroboron methyl ether group, and ethyl trifluoroboric acid group and polyiodides, thereby effectively improving the rate performance of zinc-iodine batteries; the strong polar group and high-flux Zn 2+ The electrostatic interaction between ions is significantly enhanced, which is conducive to the construction of stable and efficient ion migration channels, guiding the preferential growth of zinc along the crystal plane, effectively inhibiting the growth of zinc dendrites, and enabling the zinc-iodine battery to still have a high discharge capacity at high current density.

[0009] In another preferred embodiment, the reagent selected from the group consisting of bromomethyl potassium trifluoroborate, iodomethyl potassium trifluoroborate, boron trifluoride methyl ether complex, and ethyl potassium trifluoroborate.

[0010] In another preferred embodiment, the strongly polar group-modified dimethylaminoethyl methacrylate is obtained by the following process: A reagent containing a strong polar group is mixed with dimethylaminoethyl methacrylate in a volume ratio of 8-40:6-20, and a molecular substitution reaction is carried out in an organic reagent environment and a protective atmosphere to obtain dimethylaminoethyl methacrylate modified with a strong polar group. The protective atmosphere is nitrogen.

[0011] Mixing reagents containing strong polar groups with dimethylaminoethyl methacrylate in a ratio of 8~40:6~20 can avoid side reactions or incomplete reactions. If the volume ratio of reagents containing strong polar groups is too low, the reaction sites are not completely replaced and the product polarity is insufficient. If the ratio is too high, excess reagents compete with side reactions, resulting in an increase in by-products.

[0012] In another preferred embodiment, the organic reagent is any one of cyclohexane, acetone, dichloromethane, ethylene glycol monoethyl ether, and ethyl acetate; and the molecular substitution reaction is carried out at a temperature of 40°C to 150°C and for a time of 8 to 48 hours. By maintaining this reaction temperature and time, the reaction rate is maintained while avoiding the occurrence of polymerization side reactions.

[0013] The second aspect of the present invention provides a method for preparing the hydrogel electrolyte modified with a strong polar group, comprising the following steps: A reagent containing a strong polar group and dimethylaminoethyl methacrylate are mixed in a volume ratio of 8-40:6-20, and the mixture is reacted at a temperature of 40° C. to 150° C. for 8 h to 48 h in an organic reagent environment and a protective atmosphere to obtain dimethylaminoethyl methacrylate modified with a strong polar group; A crosslinker and an initiator are added to dimethylaminoethyl methacrylate modified with a strong polar group, acrylamide, and a zinc salt in an aqueous environment, and the mixture is stirred to obtain a mixed solution; wherein the mass volume ratio of dimethylaminoethyl methacrylate to water is 20 mg to 100 mg: 40 L to 200 mL; the mass ratio of dimethylaminoethyl methacrylate, acrylamide, and zinc salt is 20 to 100: 0.8 to 3.2: 1.2 to 6; and the mass ratio of zinc salt, crosslinker, and initiator is 1.2 to 6: 10 to 80: 1 to 10. The mixed solution is exposed to ultraviolet light to obtain the hydrogel electrolyte modified with the strong polar groups.

[0014] In another preferred embodiment, the cross-linking agent is ammonium persulfate; and the initiator is N,N'-methylenebisacrylamide.

[0015] In another preferred embodiment, the zinc salt is any one of zinc nitrate, zinc sulfate, zinc chloride, zinc trifluoromethanesulfonate, and zinc formate.

[0016] In another preferred embodiment, the stirring time for obtaining the mixed liquid is 4 hours to 18 hours, and the stirring speed is 100 r / min to 800 r / min.

[0017] In another preferred embodiment, the power of the ultraviolet irradiation is 5W~50W, and the time is 2h~10h.

[0018] The third aspect of the present invention provides the use of the hydrogel electrolyte modified with strong polar groups in the preparation of zinc-iodine batteries.

[0019] Compared with the prior art, the present invention has the following beneficial effects.

[0020] The present invention can effectively inhibit the shuttle effect of polyiodides through the strong electrostatic repulsion between any one of the strong polar groups bromomethyl trifluoroboron group, iodomethyl trifluoroboric acid group, trifluoroboron methyl ether group, and ethyl trifluoroboric acid group and polyiodides; the strong polar group and high-flux Zn 2+The electrostatic interaction between ions is significantly enhanced, which is conducive to the construction of stable and efficient ion migration channels, guiding the preferential growth of zinc along the crystal plane, effectively inhibiting the growth of zinc dendrites, and maintaining a high discharge capacity of the zinc-iodine battery. During the polymerization process, the cross-linking agent causes the acrylamide chain segments and the dimethylaminoethyl methacrylate modified with strong polar groups to link with each other and form a three-dimensional network to obtain a hydrogel skeleton. Under ultraviolet light irradiation, the initiator absorbs energy and produces free radicals, triggering the free radical copolymerization of acrylamide and the dimethylaminoethyl methacrylate modified with strong polar groups. Ultraviolet irradiation is the energy source, which precisely controls the simultaneous completion of polymerization and cross-linking, and finally obtains a hydrogel electrolyte.

[0021] The hydrogel electrolyte modified with strong polar groups in the present invention can still maintain efficient ion transport and stable electrochemical reactions at high current density, and can significantly improve the battery cycle stability and service life, achieving a long cycle life of up to 2500 hours in the Zn / / Zn symmetric battery; in the Zn / / I2 battery, the hydrogel electrolyte modified with strong polar groups in the present invention can achieve a discharge capacity of 160.3mAh / g at a high current density of 5A / g, allowing the battery to still maintain a relatively high discharge capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 For DMB 13 C NMR spectrum, where a~g represent carbon atoms at different positions respectively.

[0023] Figure 2 DMB pictures of various shapes.

[0024] Figure 3 Optical photographs for DMB thickness measurement.

[0025] Figure 4 This is the SEM image of DMB.

[0026] Figure 5 The rate performance of Zn / / Zn symmetric cells with DMA and DMB gel electrolytes is shown in the figure at 0.5, 1, 2, 3, 5, 8, and 10 mA cm -2 Indicates different current densities.

[0027] Figure 6 The graph shows the cycling performance test results of Zn / / Zn symmetric batteries with DMA and DMB gel electrolytes.

[0028] Figure 7 This is the CV curve of Zn / / I2 battery with DMB gel electrolyte.

[0029] Figure 8The charge and discharge curves of Zn / / I2 battery with DMB gel electrolyte at different current densities.

[0030] Figure 9 This is the rate performance measurement result of Zn / / I2 battery with DMB gel electrolyte. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific examples, but they should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0032] Since the zinc-iodine battery forms multiple iodides such as I 3- and I 5- The water-containing network in the hydrogel is Zn 2+ The hydrogel provides a channel for rapid transport of zinc, while the polymer backbone allows for fine-tuning of its physicochemical properties through functional group modification. Furthermore, the hydrophilic groups and charge properties of the hydrogel surface form a protective film that isolates the zinc anode surface from the electrolyte. In summary, research on optimizing hydrogel electrolytes is imperative.

[0033] In order to solve the shuttle effect and zinc dendrite problem of polyiodide in zinc-iodine battery and improve the electrochemical energy storage performance of zinc-iodine battery, the embodiment of the present invention provides a hydrogel electrolyte modified with a strong polar group. The strong polar group can have a strong electrostatic repulsion with polyiodide, and this strong electrostatic repulsion can effectively inhibit the shuttle effect of polyiodide; the strong polar group and high-flux Zn 2+ The electrostatic interaction between ions is significantly enhanced, which is conducive to the construction of stable and efficient ion migration channels, guiding the preferential growth of zinc along the crystal plane, and effectively inhibiting the growth of zinc dendrites.

[0034] In the following examples, dimethylaminoethyl methacrylate, potassium bromomethyl trifluoroborate, potassium iodomethyl trifluoroborate, boron trifluoride methyl ether complex, and potassium ethyl trifluoroborate were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0035] The following is a detailed description of a hydrogel electrolyte modified with strongly polar groups, its preparation method, and its application.

[0036] Example 1: A method for preparing a hydrogel electrolyte modified with a strong polar group, comprising the following steps.

[0037] S1, 6 mL of dimethylaminoethyl methacrylate and 8 g of potassium bromomethyltrifluoroborate were dissolved in 20 mL of acetone. The mixture was reacted at 60°C under a N2 atmosphere for 24 h. After removing the acetone under reduced pressure, the residue was repeatedly washed with ethyl acetate. The product was vacuum dried at 40°C for 48 h to obtain dimethylaminoethyl methacrylate modified with a strong polar group.

[0038] S2. Dissolve 60 mg of dimethylaminoethyl methacrylate modified with a methyl group in 30 mL of deionized water to prepare a solution; add 1.4 g of acrylamide, 2.8 g of zinc nitrate, 45 mg of ammonium persulfate, and 5 mg of N,N'-methylenebisacrylamide in sequence, and stir thoroughly at 500 rpm for 8 h to obtain a mixed solution.

[0039] S3. The mixed solution was transferred to ultraviolet light and reacted at 40W for 8 hours to complete polymerization to obtain a hydrogel electrolyte modified with strong polar groups.

[0040] Example 2: A method for preparing a hydrogel electrolyte modified with a strong polar group, comprising the following steps.

[0041] S1, 7 mL of dimethylaminoethyl methacrylate and 9 mg of potassium iodomethyl trifluoroborate were dissolved in 22 mL of cyclohexane. The mixture was reacted at 80°C under a N2 atmosphere for 20 h. After removing the cyclohexane under reduced pressure, the residue was repeatedly washed with ethyl acetate. The product was vacuum dried at 40°C for 48 h to obtain dimethylaminoethyl methacrylate modified with a strong polar group.

[0042] S2. Dissolve 80 mg of a strongly polar molecule in 50 mL of deionized water to prepare a solution; add 2.1 mg of acrylamide, 3.2 mg of zinc sulfate, 50 mg of ammonium persulfate, and 8 mg of N,N'-methylenebisacrylamide in sequence, and stir thoroughly at 300 rpm for 15 h to obtain a mixed solution.

[0043] S3. The mixed solution was transferred to ultraviolet light and reacted at 30W for 5 hours to complete polymerization to obtain a hydrogel electrolyte modified with strong polar groups.

[0044] Example 3: A method for preparing a hydrogel electrolyte modified with a strong polar group comprises the following steps.

[0045] S1, 6.5 mL of dimethylaminoethyl methacrylate and 8.5 mg of boron trifluoride methyl ether complex were dissolved in 25 mL of dichloromethane. The mixture was reacted at 100°C for 10 h under a N2 atmosphere. After removing cyclohexane under reduced pressure, the residue was repeatedly washed with ethyl acetate. The product was vacuum dried at 40°C for 48 h to obtain dimethylaminoethyl methacrylate modified with a strong polar group.

[0046] S2. Dissolve 70 mg of a strongly polar molecule in 80 mL of deionized water to prepare a solution; add 2 mg of acrylamide, 4.2 mg of zinc chloride, 60 mg of ammonium persulfate, and 4 mg of N,N'-methylenebisacrylamide in sequence, and stir thoroughly at 800 rpm for 5 h to obtain a mixed solution.

[0047] S3. The mixed solution was transferred to ultraviolet light and reacted at 50W for 2 hours to complete polymerization to obtain a hydrogel electrolyte modified with strong polar groups.

[0048] Example 4: A method for preparing a hydrogel electrolyte modified with a strong polar group comprises the following steps.

[0049] S1. Dissolve 6 mL of dimethylaminoethyl methacrylate and 8 mg of potassium ethyltrifluoroborate in 20 mL of ethylene glycol monoethyl ether. React at 60°C under N2 atmosphere for 24 hours. Remove the ethylene glycol monoethyl ether under reduced pressure, and repeatedly wash the residue with ethyl acetate. Dry the product in vacuo at 40°C for 48 hours to obtain dimethylaminoethyl methacrylate modified with a strong polar group.

[0050] S2. Dissolve 60 mg of a strongly polar molecule in 35 mL of deionized water to prepare a solution; add 1.8 mg of acrylamide, 3.3 mg of zinc trifluoromethanesulfonate, 50 mg of ammonium persulfate, and 5.4 mg of N,N'-methylenebisacrylamide in sequence, and stir thoroughly at 400 rpm for 10 h to obtain a mixed solution.

[0051] S3. The mixed solution was transferred to ultraviolet light and reacted at 45W for 4 hours to complete polymerization to obtain a hydrogel electrolyte modified with strong polar groups.

[0052] The above Examples 1 to 3 all prepared a hydrogel electrolyte modified with a strong polar group, and the effects were comparable. The hydrogel electrolyte modified with a strong polar group in Example 1 is used as an example for description.

[0053] The hydrogel electrolyte modified with strong polar groups prepared in Example 1 was denoted as DMB, and the hydrogel electrolyte not modified with strong polar groups was denoted as DMA, and served as a control.

[0054] 1. Structural characterization.

[0055] DMB 13 C NMR Figure 1 As shown, the dimethylaminoethyl methacrylate modified with a strong polar group prepared in Example 1 was subjected to a 400 MHz spectral analysis with D2O as solvent. 1H NMR spectroscopy showed chemical shifts of 6.07–6.02 (1H), 5.52–5.47 (1H), 4.59–4.46 (2H), 3.79–3.65 (2H), 3.39–3.26 (2H), 3.21–3.04 (6H), 1.84–1.78 (3H), 1.73–1.58 (2H), 1.29–1.05 (22H), and 0.81–0.70 (3H).

[0056] DMB hydrogel electrolyte has excellent mechanical flexibility and shape adaptability. It can be easily formed into various complex shapes during various mechanical operations and maintains structural integrity throughout the process without cracking, delamination or other damage, showing excellent mechanical stability and durability. It can be prepared into any shape, such as Figure 2 The thickness of DMB is 0.38mm. The measurement process is shown in the picture below. Figure 3 shown.

[0057] DMB was scanned by electron microscope, and the results were as follows Figure 4 As shown, from Figure 4 It can be seen that the widely distributed and interconnected pore structure within the DMB hydrogel electrolyte gives it a significant specific surface area. This unique microstructure not only significantly enhances the adsorption and retention capacity of the electrolyte, but also provides unobstructed transmission channels for dissolved ions, thereby greatly improving the ion transmission efficiency and the overall performance of the electrolyte.

[0058] 2. Performance determination of Zn / / Zn symmetrical battery.

[0059] 1) Rate performance test of Zn / / Zn symmetrical battery. The specific test process is as follows.

[0060] 0.5mA / cm 2 ,1mA / cm 2 ,2mA / cm 2 ,3mA / cm 2 ,5mA / cm 2 ,8mA / cm 2 ,10mA / cm 2 The current density and the fixed 1mAh / cm 2 Under the surface capacity, the rate performance test of Zn / / Zn symmetric battery was carried out with DMB as electrolyte, and the results are as follows Figure 5As shown in the figure, compared with the Zn / / Zn symmetric battery without DMA, the Zn / / Zn symmetric battery using DMB hydrogel electrolyte exhibits significantly better rate performance. Its voltage curve remains highly stable over different current density ranges, indicating that DMB can still maintain efficient ion transport and stable electrochemical reactions at high current density.

[0061] 2) Cycling performance test of Zn / / Zn symmetrical battery. The specific test process is as follows.

[0062] Using an electrochemical tester, at 1 mA / cm 2 The current density and 1mAh / cm 2 The long cycle test was carried out under the condition of surface capacity. The results are as follows Figure 6 As shown in the figure, at 1mA / cm 2 The current density and 1 mAh / cm 2 Under the condition of the surface capacity of the battery, the Zn / / Zn symmetric battery using DMB can achieve a long cycle life of up to 2500 hours, which is much better than the Zn / / Zn symmetric battery without DMA gel electrolyte, which only lasts about 150 hours. This shows that DMB hydrogel electrolyte has outstanding advantages in significantly improving battery cycle stability and service life.

[0063] 3. Zn / / I2 battery determination.

[0064] 1) Zn / / I2 battery CV curve. The specific test process is as follows.

[0065] The CV test was performed at a scan rate of 0.5mV / s and a voltage range of 0.5V~1.6V. The results are as follows Figure 7 As shown. Figure 7 The cyclic voltammetry (CV) curves shown in Figure 2 show that the Zn / / I2 battery using DMB gel electrolyte exhibits good electrochemical performance. The two distinct current peaks in the curve indicate that effective oxidation and reduction reactions occur in the battery. These reactions are reversible, indicating high energy conversion efficiency.

[0066] 2) Charge and discharge curves of Zn / / I2 battery at different current densities.

[0067] Different current densities of 0.25A / g, 0.5A / g, 1A / g, 2.5A / g, 4A / g and 5A / g and a fixed current density of 1mAh / cm 2 Under the surface capacity, the Zn / / I2 battery rate performance test was carried out with DMB as the electrolyte. The results are as follows Figure 8As shown. In the rate performance test, the Zn / / I2 battery using DMB gel electrolyte showed excellent performance. As the current density gradually increased to 0.25A / g, 0.5A / g, 1A / g, 2.5A / g, 4A / g and 5A / g, the discharge capacity of the battery reached 220.7mAh / g, 210.6mAh / g, 201.0mAh / g, 165.6mAh / g and 160.3mAh / g, respectively. These data highlight the significant advantages of DMB in improving electrochemical performance. Even at high current density, the battery can still maintain a high discharge capacity, demonstrating its potential in fast charge and discharge applications.

[0068] 3) Rate performance of Zn / / I2 battery.

[0069] like Figure 9 As shown, the Zn / / I2 battery using DMB gel electrolyte performs well at different rates. Even at high rates, the battery can maintain a high specific discharge capacity, showing excellent rate performance and cycle stability.

[0070] The above description is merely a preferred embodiment of the present invention, and the above specific embodiment is not intended to limit the present invention. Various variations and modifications are possible within the technical scope of the present invention. Any modifications, alterations, or equivalent substitutions made by a person skilled in the art based on the above description are within the scope of protection of the present invention.

Claims

1. A hydrogel electrolyte modified with a strong polar group, characterized in that: The hydrogel electrolyte is prepared by modifying dimethylaminoethyl methacrylate with a strong polar group to obtain dimethylaminoethyl methacrylate modified with a strong polar group; mixing the dimethylaminoethyl methacrylate modified with a strong polar group, acrylamide and zinc salt, adding a crosslinking agent and an initiator to obtain a mixed solution, and subjecting the mixed solution to ultraviolet irradiation. The strong polar group is any one of a bromomethyl trifluoroboron group, an iodomethyl trifluoroboric acid group, a boron trifluoride methyl ether group, and an ethyl trifluoroboric acid group.

2. The hydrogel electrolyte modified with strongly polar groups according to claim 1, characterized in that The reagent selected from the group consisting of bromomethyl potassium trifluoroborate, iodomethyl potassium trifluoroborate, boron trifluoride methyl ether complex, and ethyl potassium trifluoroborate.

3. The hydrogel electrolyte modified with strong polar groups according to claim 2, characterized in that The specific process for obtaining the strongly polar group-modified dimethylaminoethyl methacrylate is as follows: A reagent containing a strong polar group is mixed with dimethylaminoethyl methacrylate in a volume ratio of 8-40:6-20, and a molecular substitution reaction is carried out in an organic reagent environment and a protective atmosphere to obtain dimethylaminoethyl methacrylate modified with a strong polar group.

4. The hydrogel electrolyte modified with strongly polar groups according to claim 3, characterized in that The organic reagent is any one of cyclohexane, acetone, dichloromethane, ethylene glycol monoethyl ether, and ethyl acetate; The temperature of the molecular substitution reaction is 40° C. to 150° C., and the time is 8 h to 48 h.

5. A method for preparing the hydrogel electrolyte modified with a strong polar group according to claim 4, characterized in that: The following steps are involved: A reagent containing a strong polar group and dimethylaminoethyl methacrylate are mixed in a volume ratio of 8-40:6-20, and the mixture is reacted at 40° C. to 150° C. for 8 h to 48 h in an organic reagent environment and a protective atmosphere to obtain dimethylaminoethyl methacrylate modified with a strong polar group; A crosslinking agent and an initiator are added to dimethylaminoethyl methacrylate modified with a strong polar group, acrylamide, and a zinc salt in an aqueous environment, and the mixture is stirred to obtain a mixed solution; wherein the mass volume ratio of dimethylaminoethyl methacrylate modified with a strong polar group to water is 20 mg~100 mg:30 mL~200 mL; the mass ratio of dimethylaminoethyl methacrylate modified with a strong polar group to acrylamide to zinc salt is 20~100:0.8~3.2:1.2~6; and the mass ratio of zinc salt to crosslinker to initiator is 1.2~6:10~80:1~10; The mixed solution is exposed to ultraviolet light to obtain the hydrogel electrolyte modified with the strong polar groups.

6. The method for preparing a hydrogel electrolyte modified with a strong polar group according to claim 5, characterized in that: The cross-linking agent is ammonium persulfate; the initiator is N,N'-methylenebisacrylamide.

7. The method for preparing a hydrogel electrolyte modified with a strong polar group according to claim 5, characterized in that: The zinc salt is any one of zinc nitrate, zinc sulfate, zinc chloride, zinc trifluoromethanesulfonate, and zinc formate.

8. The method for preparing a hydrogel electrolyte modified with a strong polar group according to claim 5, characterized in that: The stirring time in the process of stirring to obtain the mixed liquid is 4 hours to 18 hours, and the stirring speed is 100 r / min to 800 r / min.

9. The method for preparing a hydrogel electrolyte modified with a strong polar group according to claim 5, characterized in that: The power of the ultraviolet irradiation is 5W~50W, and the time is 2h~10h.

10. Use of the strongly polar group-modified hydrogel electrolyte according to claim 4 in the preparation of a zinc-iodine battery.

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