Anti-freezing hydrogel electrolyte as well as preparation method and application thereof

Abstract

The invention discloses an anti-freezing hydrogel electrolyte as well as a preparation method and application thereof. Comprising the following steps: dissolving a zinc salt in water to obtain a zinc salt solution, adding an acrylamide monomer, an additive, an initiator and a cross-linking agent into the zinc salt solution to obtain a zinc salt mixed solution, degassing the zinc salt mixed solution, and carrying out thermal initiation polymerization to obtain the anti-freezing hydrogel electrolyte, wherein the additive is zinc phytate, the initiator is ammonium persulfate, and the cross-linking agent is N, N '-methylene bisacrylamide. According to the electrolyte, acrylamide is used as a monomer to be polymerized in a zinc salt aqueous solution to form a PAM hydrogel system, a zinc phytate component is introduced, the water molecule state and the zinc ion solvation structure are regulated and controlled through the polydentate coordination effect, the free water content is remarkably reduced, and the water crystallization behavior under the low-temperature condition is effectively inhibited. In an ultralow temperature environment, the hydrogel electrolyte can keep a continuous zinc ion transmission channel, and shows good ion transmission capability, zinc deposition / stripping stability and interface stability.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage materials technology, and particularly relates to an antifreeze hydrogel electrolyte, its preparation method and application. Background Technology

[0002] In recent years, aqueous zinc-ion batteries (ZIBs) have shown broad application prospects in large-scale energy storage and cryogenic energy storage due to their advantages such as high theoretical capacity, high safety, low cost, and environmental friendliness. As an important component of aqueous zinc batteries, hydrogel electrolytes combine the high ion transport capacity of liquid electrolytes with the structural stability of solid electrolytes and have been widely used in zinc battery systems. However, because hydrogels typically contain a high proportion of free water molecules, they are prone to freezing at low temperatures. The ordered crystallization of free water significantly hinders the migration of zinc ions and causes embrittlement of the gel network structure, leading to a decrease in electrolyte ionic conductivity and deterioration of mechanical properties, thus severely limiting the stable operation of aqueous zinc batteries in low-temperature environments.

[0003] To improve the low-temperature performance of hydrogel electrolytes, existing research mainly focuses on lowering the freezing temperature by increasing salt concentration, introducing organic solvents, or constructing complex network structures. However, high-concentration salt systems often suffer from increased viscosity, restricted ion migration, and exacerbated interfacial side reactions; the introduction of organic solvents may affect the safety and long-term stability of the electrolyte; and complex network or multi-component hydrogels have limitations in preparation processes and performance control, making it difficult to simultaneously ensure good ion transport capacity and mechanical stability while maintaining low-temperature antifreeze performance. Therefore, developing an aqueous antifreeze hydrogel electrolyte that can effectively suppress water crystallization at low temperatures while maintaining good ion conductivity and mechanical properties remains a key technical problem that urgently needs to be solved in the field of aqueous zinc batteries. To address these issues, this invention provides an antifreeze hydrogel electrolyte, its preparation method, and its applications. By introducing coordination regulation, it effectively suppresses water crystallization at low temperatures, maintaining good mechanical properties while ensuring ion transport capacity, thus providing an innovative solution for the stable operation of aqueous zinc batteries under low-temperature conditions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an antifreeze hydrogel electrolyte, its preparation method, and its application.

[0005] According to a first aspect of the present invention, a method for preparing an antifreeze hydrogel electrolyte is provided, comprising the following steps: dissolving a zinc salt in water to obtain a zinc salt solution; adding an acrylamide monomer, an additive, an initiator, and a crosslinking agent to the zinc salt solution to obtain a zinc salt mixed solution; and subjecting the zinc salt mixed solution to thermally initiated polymerization after degassing to obtain the antifreeze hydrogel electrolyte; wherein the additive is zinc phytate, the initiator is ammonium persulfate, and the crosslinking agent is N,N′-methylenebisacrylamide.

[0006] According to a second aspect of the present invention, an antifreeze hydrogel electrolyte is provided.

[0007] According to a third aspect of the invention, the application of an antifreeze hydrogel electrolyte is provided, in which an aqueous zinc-ion battery is constructed using the antifreeze hydrogel electrolyte for electrochemical testing.

[0008] The principle of this invention is as follows:

[0009] Introducing zinc phytate into the hydrogel electrolyte system allows multiple phosphate groups (–PO4³⁻) in the zinc phytate molecule to simultaneously engage in multi-site Zn–O coordination with Zn²⁺, competing with or substituting with water molecules originally located in the first solvation shell of Zn²⁺. Through this multidentate coordination mechanism, the solvation structure of Zn²⁺ is reconstructed, converting some free water molecules into coordinated or bound water, thereby reducing the proportion of free water in the system, increasing the degree of water molecule confinement, and reducing its tendency to form ice crystals under low-temperature conditions.

[0010] Meanwhile, the multidentate coordination structure provided by zinc phytate can form hydrogen bonds or weak coordination interactions with acrylamide polymer segments, further altering the local microenvironment of the gel network. This allows the resulting hydrogel to maintain a more stable three-dimensional network structure at low temperatures, avoiding the embrittlement, cracking, and structural damage caused by freezing in conventional gels. This structural stability enables the hydrogel electrolyte to maintain continuous Zn²⁺ transport channels even at extremely low temperatures, achieving effective ion migration.

[0011] Furthermore, the reconstruction of the solvation structure lowers the desolvation barrier of Zn²⁺ and makes the local current density on the electrode surface more uniform. This also helps to suppress the formation of zinc dendrites and the occurrence of side reactions under low-temperature conditions. Thus, the synergistic mechanism of multidentate coordination-solvation regulation-network stabilization enables the hydrogel electrolyte of this invention to simultaneously possess excellent ionic conductivity, interfacial stability, and structural integrity in low-temperature and even ultra-low-temperature environments.

[0012] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0013] The method for preparing the antifreeze hydrogel electrolyte of this invention is simple, with a clearly defined raw material system, requiring no complex post-processing steps, and offers advantages such as controllable process, adjustable formulation, and ease of large-scale preparation. The antifreeze hydrogel electrolyte prepared by this invention retains excellent antifreeze performance and ion transport capabilities even at extremely low temperatures. For example, a Zn||Zn symmetric battery constructed based on this hydrogel electrolyte maintains stable zinc plating / stripping behavior and a low polarization voltage at -60℃; in a full-cell system, the electrolyte exhibits good cycle stability and capacity retention at low temperatures. Simultaneously, the hydrogel electrolyte of this invention maintains good mechanical properties in low-temperature environments, and its structural integrity does not significantly deteriorate after tensile testing, ensuring reliable performance even under low-temperature and mechanical disturbance conditions. Based on these characteristics, the hydrogel electrolyte of this invention has broad application prospects in the fields of wide-temperature-range aqueous zinc-ion batteries and flexible energy storage devices. Attached Figure Description

[0014] Figure 1 Electrochemical impedance spectroscopy (EIS) Nyquist plots of the hydrogel electrolytes prepared in Examples 1 (PAM-ZnSO4-3ZP), 2 (PAM-ZnSO4-1ZP), 3 (PAM-ZnSO4-5ZP), and Comparative Example 1 (PAM-ZnSO4) under different temperature conditions.

[0015] Figure 2 Comparison of tensile stress-strain curves of hydrogel electrolytes prepared in Examples 1 (PAM-ZnSO4-3ZP), 2 (PAM-ZnSO4-1ZP), 3 (PAM-ZnSO4-5ZP), and Comparative Example 1 (PAM-ZnSO4) of the present invention.

[0016] Figure 3 Raman spectra and peak fitting results of the -OH vibration peaks of different hydrogel electrolyte samples prepared in Examples 1, 2, 3 and Comparative Example 1 of this invention in the wavenumber range of 3000–3800 cm⁻¹;

[0017] Figure 4 A statistical comparison chart of the peak area ratios of three types of hydrogen-bonded water molecules (strong hydrogen-bonded water, medium hydrogen-bonded water, and weak hydrogen-bonded water) in different hydrogel electrolyte samples prepared in Examples 1, 2, 3 and Comparative Example 1 of this invention.

[0018] Figure 5 A schematic diagram of the interfacial adhesion state between the antifreeze hydrogel electrolyte prepared in Example 1 of the present invention (PAM-ZnSO4-3ZP) and zinc sheet, copper sheet, carbon paper and plastic cap after standing at -60℃ for 24h.

[0019] Figure 6 The performance test results of Zn||Zn symmetric cells assembled with hydrogel electrolytes prepared in Example 1 (PAM-ZnSO4-3ZP) and Comparative Example 1 (PAM-ZnSO4) under different current densities are compared, and the results of long-cycle stability tests conducted under 1 mA·cm⁻² and 1 mAh·cm⁻² conditions are also shown in the figure.

[0020] Figure 7 Figure 1 shows the cycle stability test results of the Zn||Zn symmetric battery assembled by the hydrogel electrolyte prepared in Example 1 of this invention (PAM-ZnSO4-3ZP) under the conditions of -20℃, current density of 1mA·cm⁻², and deposition capacity of 1mAh·cm⁻².

[0021] Figure 8 A comparison of the Tafel polarization curves of the zinc electrodes corresponding to the hydrogel electrolytes prepared in Examples 1 (PAM-ZnSO4-3ZP), 2 (PAM-ZnSO4-1ZP), 3 (PAM-ZnSO4-5ZP), and Comparative Example 1 (PAM-ZnSO4) of this invention.

[0022] Figure 9 Figure 1 shows the cycle performance test results of the aqueous zinc-ion full cell assembled with the antifreeze hydrogel electrolyte prepared in Example 1 of the present invention (PAM-ZnSO4-3ZP) under different temperature conditions at a current density of 1A·g⁻¹.

[0023] Figure 10 The constant current charge-discharge curves of the aqueous zinc-ion full cell assembled with the antifreeze hydrogel electrolyte prepared in Example 1 of the present invention (PAM-ZnSO4-3ZP) under different temperature conditions at a current density of 1A·g⁻¹.

[0024] Figure 11 The figure shows the long-cycle performance test results of the aqueous zinc-ion full cell assembled with the antifreeze hydrogel electrolyte prepared in Example 1 of the present invention (PAM-ZnSO4-3ZP) at a current density of 1A·g⁻¹ under the condition of -40℃. Detailed Implementation

[0025] The present invention is further illustrated below by way of embodiments, but these embodiments are not intended to limit the invention to the scope of the embodiments described. The described embodiments are some, but not all, of the embodiments disclosed herein. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present disclosure.

[0026] Example 1

[0027] (1) Zinc sulfate heptahydrate was dissolved in water to prepare a zinc salt solution with a molar concentration of 2 mol·L⁻¹. Zinc phytate was added to the zinc salt solution, and the zinc phytate was fully dissolved in the zinc salt solution in the presence of trace amounts of phytic acid, with a molar concentration of 0.03 mol·L⁻¹. Acrylamide monomer, initiator and crosslinking agent were then added to the above mixed solution, wherein the acrylamide monomer served as the hydrogel skeleton monomer, the initiator was ammonium persulfate, and the crosslinking agent was N,N′-methylenebisacrylamide. The mass ratio of initiator to acrylamide was 0.002~0.006:1, and the mass ratio of crosslinking agent to acrylamide was 0.0003~0.002:1. The mixture was stirred to form a precursor solution for the antifreeze hydrogel electrolyte.

[0028] (2) After degassing the precursor solution for 10-30 min, it is cast into a mold and subjected to free radical polymerization at 60°C for 2 h to obtain an antifreeze hydrogel electrolyte, which is a polyacrylamide-zinc sulfate antifreeze hydrogel electrolyte containing 0.03 mol·L⁻¹ zinc phytate, denoted as PAM-ZnSO4-3ZP. Wherein, PAM represents the polyacrylamide skeleton, ZnSO4 represents the zinc sulfate electrolyte system, and ZP represents the introduction of the zinc phytate component.

[0029] Example 2

[0030] The only difference between Example 2 and Example 1 is that in step (1), the molar concentration of zinc phytate added is 0.01 mol·L⁻¹. The other steps are the same and will not be described again. The antifreeze hydrogel electrolyte obtained in Example 2 is a polyacrylamide-zinc sulfate antifreeze hydrogel electrolyte containing 0.01 mol·L⁻¹ zinc phytate, denoted as PAM-ZnSO4-1ZP.

[0031] Example 3

[0032] The only difference between Example 3 and Example 1 is that in step (1), the molar concentration of zinc phytate added is 0.05 mol·L⁻¹. The other steps are the same and will not be described again. The antifreeze hydrogel electrolyte obtained in Example 3 is a polyacrylamide-zinc sulfate antifreeze hydrogel electrolyte containing 0.05 mol·L⁻¹ zinc phytate, denoted as PAM-ZnSO4-5ZP.

[0033] Comparative Example 1

[0034] The difference between Comparative Example 1 and Example 1 is that zinc phytate and phytic acid components are not added in step (1). The remaining preparation steps are the same as in Example 1 and will not be repeated. The hydrogel electrolyte obtained in Comparative Example 1 is a polyacrylamide-zinc sulfate hydrogel electrolyte without the introduction of zinc phytate, denoted as PAM-ZnSO4.

[0035] The performance and electrochemical properties of the four hydrogel electrolytes prepared in Examples 1-3 and Comparative Example 1 were tested using the following methods:

[0036] (1) Ionic conductivity test.

[0037] Four types of hydrogel electrolytes were sandwiched between two stainless steel electrodes, and electrochemical impedance spectroscopy (EIS) was performed using an electrochemical workstation to obtain the impedance values ​​of the hydrogel electrolytes. Their ionic conductivity was then calculated using the following formula:

[0038] σ = L / (R × S);

[0039] Where L is the thickness of the hydrogel electrolyte, R is the impedance value measured by EIS, and S is the effective contact area between the hydrogel electrolyte and the stainless steel electrode. The EIS data is derived from... Figure 1 Given, where: Figure 1 (a) EIS curve of Comparative Example 1 (PAM-ZnSO4); Figure 1 (b) EIS curve of Example 2 (PAM-ZnSO4-1ZP); Figure 1 (c) EIS curve of Example 1 (PAM-ZnSO4-3ZP); Figure 1 (d) is the EIS curve of Example 3 (PAM-ZnSO4-5ZP). Figure 1 Each subplot was tested under different temperature conditions using EIS to compare the ion conductivity of different hydrogel electrolytes in low-temperature environments.

[0040] The ionic conductivity test results of each embodiment and comparative example under different temperature conditions are shown in Table 1.

[0041] Table 1: Conductivity Test Results (mS cm) -1 )

[0042] Temperature (°C) Example 1 Example 2 Example 3 Comparative Example 1 20 29.09 20.94 18.05 13.39 10 20.94 19.99 16.89 11.76 0 15.4 8.59 12.47 6.7 -10 10.07 6.63 10.47 1.24 -20 6.31 4 5.45 0.42 -30 4.44 1.67 3.32 0.12 -40 3.12 0.59 2.47 / -50 2.53 0.18 1.07 / -60 2.01 0.08 0.547 /

[0043] As shown in Table 1, the ionic conductivity of all samples decreased with decreasing temperature. However, Examples 1-3 exhibited significantly higher ionic conductivity than Comparative Example 1 at temperatures ranging from 20℃ to -60℃. Especially at low temperatures, Comparative Example 1 could not obtain stable conductivity data at -40℃ and below, while Examples 1-3 maintained measurable ionic conductivity at -60℃. Specifically, Example 1 maintained an ionic conductivity as high as 2.01 mS·cm⁻¹ at -60℃, significantly better than the PAM-ZnSO4 of Comparative Example 1.

[0044] (2) Tensile property test.

[0045] The four types of hydrogel electrolyte samples were cut into rectangular specimens and subjected to tensile tests on a ZQ-990LB universal testing machine. The gauge length of the four hydrogel electrolyte samples was 30 mm, the thickness was 1 mm, the width was 6 mm, and the tensile rate was 100 mm / min.

[0046] The tensile properties of the hydrogel electrolytes prepared in Examples 1 (PAM-ZnSO4-3ZP), 2 (PAM-ZnSO4-1ZP), 3 (PAM-ZnSO4-5ZP), and Comparative Example 1 (PAM-ZnSO4) of this invention are as follows: Figure 2 As shown. Figure 2 Different curves are labeled with legends to represent different samples, used to compare the differences in mechanical properties among the samples. It can be seen that, compared to Comparative Example 1, the hydrogel electrolytes prepared in Examples 1-3 exhibit higher fracture strain and better mechanical integrity. These results indicate that the introduction of zinc phytate improves the mechanical properties of the hydrogel electrolyte, helping it maintain structural integrity and stability under low temperature or external force conditions.

[0047] (3) Water state form test.

[0048] Raman spectroscopy was used to analyze the state of water molecules in the four different hydrogel electrolyte samples. The tests were performed on a Thermo Scientific DXR3 micro Raman spectrometer with an excitation wavelength of 532 nm. The Raman spectra of the four hydrogel electrolytes in Examples 1-3 and Comparative Example 1 are shown below. Figure 3 and Figure 4 As shown. Figure 3 The images show the Raman spectra and peak fitting results of the –OH vibration peaks of different hydrogel electrolyte samples prepared in Examples 1, 2, 3 and Comparative Example 1 of this invention in the wavenumber range of 3000–3800 cm⁻¹. Figure 3The peak fitting results are shown below for: PAM-ZnSO4 (Comparative Example 1); PAM-ZnSO4-1ZP (Example 2); PAM-ZnSO4-3ZP (Example 1); and PAM-ZnSO4-5ZP (Example 3). Each spectrum contains three fitted peaks, corresponding to three water molecule states: strongly hydrogen-bonded water, moderately hydrogen-bonded water, and weakly hydrogen-bonded water, respectively, to reflect the differences in hydrogen bonding environment among different samples. Figure 4 This is a statistical comparison of the peak area percentages of three types of hydrogen-bonded water molecules (strongly hydrogen-bonded water, moderately hydrogen-bonded water, and weakly hydrogen-bonded water) in different hydrogel electrolyte samples prepared in Examples 1, 2, 3, and Comparative Example 1 of this invention. The bar charts show: PAM-ZnSO4 (Comparative Example 1); PAM-ZnSO4-1ZP (Example 2); PAM-ZnSO4-3ZP (Example 1); PAM-ZnSO4-5ZP (Example 3). The sum of the peak area percentages of the three types of water molecules is 100%, used to characterize the differences in the hydrogen bond structure of water molecules in different hydrogel samples and the regulatory effect of the introduction of zinc phytate. Figure 3-4 As can be seen, the characteristic peak distributions related to water molecules in the hydrogel electrolytes prepared in Examples 1-3 are significantly different from those in Comparative Example 1, indicating that the state of water molecules in the hydrogel system changes after the introduction of zinc phytate. These results demonstrate that by introducing zinc phytate, the state of water molecules in the hydrogel system can be regulated, thereby reducing the proportion of free water and altering the hydrogen bond structure of water molecules, which is beneficial for reducing the probability of water crystallization under low-temperature conditions.

[0049] (4) Low-temperature interfacial adhesion retention test.

[0050] To evaluate the compatibility and stability of the hydrogel electrolyte of this invention with different battery component interfaces under low-temperature conditions, the hydrogel electrolyte prepared in the embodiments of this invention was bonded to zinc sheets, copper sheets, carbon paper, and plastic caps, respectively, and then placed in a -60 ℃ low-temperature environment for 24 hours. After removal, the interfacial bonding state between the hydrogel electrolyte and each substrate was observed, and the results are as follows: Figure 5 As shown in the figure. Test results indicate that after prolonged standing under ultra-low temperature conditions, the hydrogel electrolyte prepared in this invention can still maintain good interfacial adhesion with the zinc sheet, copper sheet, carbon paper, and plastic cap, without obvious debonding, lifting, or interface separation. These results demonstrate that the hydrogel electrolyte prepared in this invention has good interfacial compatibility and dimensional stability in low-temperature environments, which is beneficial for maintaining continuous contact at the electrode / electrolyte interface, thereby improving the operational stability of aqueous zinc-ion batteries under low-temperature conditions.

[0051] (5) Cyclic performance test of zinc symmetric battery.

[0052] The antifreeze hydrogel electrolyte prepared in the embodiments of the present invention was cut into 16mm diameter discs using a punch, assembled into Zn||Zn symmetric coin cells, and its cycle stability was tested under different temperature conditions. Figure 6 As shown, when the hydrogel electrolyte prepared in Comparative Example 1 is used as the electrolyte, the Zn||Zn symmetric battery exhibits significant polarization and exceeds the test range at a current density of 10 mA·cm⁻², making it difficult to maintain stable cycling. In contrast, when using the hydrogel electrolyte prepared in Example 1 of this invention, the Zn||Zn symmetric battery can still operate stably under current densities as high as 50 mA·cm⁻², demonstrating excellent high-rate carrying capacity. Even after switching to 1 mA·cm⁻² and 1 mAh·cm⁻² conditions, the symmetric battery using the hydrogel electrolyte prepared in Example 1 of this invention can still cycle stably for over 700 hours with minimal voltage fluctuation. Furthermore, as... Figure 7 As shown, at -20℃ and a current density of 1 mA·cm⁻², the Zn||Zn symmetric cell based on Example 1 can operate continuously and stably for 800 hours without significant increase in voltage polarization, indicating that the hydrogel electrolyte prepared in this invention can effectively maintain the reversible deposition / stripping behavior of zinc. Furthermore, as... Figure 8 The Tafel polarization curves shown indicate that when using the hydrogel electrolyte provided in Example 1, the zinc electrode exhibits a lower corrosion current density, demonstrating that the electrolyte system prepared in this invention can effectively suppress the corrosion reaction and dendrite growth of the zinc anode, which is beneficial for achieving uniform zinc deposition. The above test results show that the hydrogel electrolyte provided in this invention can effectively maintain the stability of the ion transport channels and electrode / electrolyte interface inside the battery under low and even ultra-low temperature conditions, significantly improving the cycle stability of aqueous zinc-ion batteries under low temperature conditions. It is suitable for aqueous zinc-ion batteries and flexible energy storage device applications under wide temperature range conditions.

[0053] (6) Full battery performance test.

[0054] Using phytic acid-doped polyaniline (PANI-PA) as the positive electrode material and zinc sheet as the negative electrode material, the hydrogel electrolyte prepared in this invention serves as both the electrolyte and the separator, assembling an aqueous zinc-ion full battery, and testing its electrochemical performance under different temperature conditions. Figure 9 and Figure 10 As shown, under a current density of 1 A·g⁻¹, the assembled full cell achieves a specific capacity of 156.7 mAh·g⁻¹ at 20°C; it maintains a specific capacity of 113.1 mAh·g⁻¹ at -20°C; and even in an ultra-low temperature environment of -60°C, the full cell can still output a specific capacity of approximately 50.4 mAh·g⁻¹. Furthermore, as... Figure 11As shown, at a temperature of -40℃, the aqueous zinc-ion batteries constructed based on the hydrogel electrolyte prepared in this invention all exhibit relatively stable charge-discharge behavior and good capacity retention.

[0055] The above test results demonstrate that the hydrogel electrolyte provided by this invention can effectively maintain the stability of ion transport channels and interfaces within the battery under extremely low temperature conditions, exhibiting strong antifreeze properties, thereby significantly improving the operating performance of aqueous zinc-ion batteries in low and even ultra-low temperature environments. This has certain research significance for promoting flexible electronic devices and large-scale energy storage applications. It should be understood that the low or ultra-low temperature conditions described in this invention include, but are not limited to, operating environment temperature ranges such as -20℃, -40℃, and -60℃.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. For those skilled in the art, various modifications or equivalent substitutions can be made to the present invention without departing from its spirit and essence, and all such modifications or equivalent substitutions should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing an antifreeze hydrogel electrolyte, characterized in that, Includes the following steps: A zinc salt is dissolved in water to obtain a zinc salt solution. Acrylamide monomer, additive, initiator and crosslinking agent are added to the zinc salt solution to obtain a zinc salt mixed solution. The zinc salt mixed solution is degassed and then subjected to thermally initiated polymerization to obtain an antifreeze hydrogel electrolyte. The additive is zinc phytate, the initiator is ammonium persulfate, and the crosslinking agent is N,N′-methylenebisacrylamide.

2. The preparation method according to claim 1, characterized in that, The zinc salt is selected from zinc sulfate, zinc fluoroborate, zinc trifluoromethanesulfonate, zinc acetate, or their hydrates, and the molar concentration of the zinc salt solution is 2 mol·L⁻¹.

3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of the initiator to the acrylamide monomer is 0.002 to 0.006:1, and the mass ratio of the crosslinking agent to the acrylamide monomer is 0.0003 to 0.002:

1.

4. The preparation method according to claim 1, characterized in that, The molar concentration of zinc phytate is 0.01–0.05 mol·L⁻¹.

5. The preparation method according to claim 1, characterized in that, Specifically, the steps include the following: (1) Add zinc salt to water and mix and stir to obtain the first solution; (2) Add the acrylamide monomer to the first solution and mix and stir to obtain the second solution; (3) Add zinc phytate to the second solution and mix and stir to obtain a third solution; phytic acid may be added to promote the dissolution of zinc phytate. (4) Add the initiator and crosslinking agent to the third solution and mix and stir to obtain the precursor solution; (5) The precursor solution is degassed and then cast into shape, and heated at 60~80 ℃ for 2~6 h to obtain an antifreeze hydrogel electrolyte.

6. An antifreeze hydrogel electrolyte obtained by the preparation method according to any one of claims 1-5.

7. The application of the antifreeze hydrogel electrolyte according to claim 6, characterized in that, An aqueous zinc-ion battery was constructed using the aforementioned antifreeze hydrogel electrolyte and electrochemical tests were conducted.

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