Flexible low-temperature-resistant gel electrolyte and application thereof in aqueous battery

Abstract

The invention discloses a flexible low-temperature-resistant gel electrolyte and application of the flexible low-temperature-resistant gel electrolyte in an aqueous battery, and belongs to the technical field of aqueous ion battery electrolytes. The preparation method of the flexible low-temperature-resistant gel electrolyte comprises the following steps: dissolving zinc perchlorate in deionized water to prepare a zinc perchlorate electrolyte solution, and adding acrylamide and N-acetyl-L-glutamine into the zinc perchlorate electrolyte solution to form a mixed solution; adding a cross-linking agent and an initiator into the mixed solution for complete dissolution to obtain a hydrogel precursor solution, and sequentially performing ultrasonic defoaming and heating curing on the hydrogel precursor solution to obtain the hydrogel. By introducing N-acetyl-L-glutamine, the activity and freezing point of free water are greatly reduced, and the N-acetyl-L-glutamine and a polymer chain form a dynamic hydrogen bond, so that the mechanical strength, low temperature resistance and electrochemical stability of the electrolyte are synergistically improved, and the problems of dendritic crystal growth, interface side reaction, low-temperature failure and the like of a zinc battery are effectively solved; and an ideal electrolyte material is provided for flexible and low-temperature energy storage devices.

Description

Technical Field

[0001] This invention relates to the field of aqueous ion battery electrolyte technology, specifically to the application of flexible low-temperature resistant gel electrolyte in aqueous batteries. Background Technology

[0002] Aqueous zinc-ion batteries (AZIBs) have become ideal candidates for large-scale energy storage systems and energy storage devices for flexible wearable electronic devices in recent years due to their abundant zinc resources, high electrochemical safety, and environmental friendliness, showing broad application prospects in the field of new energy storage. However, traditional aqueous zinc-ion batteries face many technical bottlenecks in practical applications: zinc dendrites are easily generated on the zinc anode during charge-discharge cycles, causing internal short circuits in the battery; at the same time, side reactions such as hydrogen evolution reaction and zinc anode corrosion occur, and the liquid electrolyte is prone to leakage, which seriously restricts the battery's cycle life and safety performance; especially in the context of flexible electronic devices, traditional glass fiber separators have low mechanical strength and poor interfacial adhesion, and are easily damaged by external forces such as bending and folding, further reducing battery reliability.

[0003] To address these issues, researchers have proposed a technical solution using hydrogel electrolytes to replace traditional liquid electrolytes and separators. The three-dimensional porous polymer network of hydrogels enables uniform ion transport, guides uniform zinc ion deposition to suppress dendrite growth, and offers features such as leak-free operation and high safety. Furthermore, its flexibility and adhesion can adapt to the deformation requirements of flexible batteries. However, existing hydrogel electrolytes still suffer from drawbacks such as low ionic conductivity, uneven pore structure, and insufficient mechanical strength. They are particularly prone to freezing at low temperatures, leading to a sharp drop in ion conductivity and failing to meet the application requirements of extreme low-temperature scenarios. Therefore, developing hydrogel electrolytes that combine flexibility, high ionic conductivity, and low-temperature tolerance has become a key breakthrough direction for the industry. Currently, some patents have proposed technical solutions for optimizing the performance of hydrogel electrolytes, but many shortcomings remain.

[0004] Patent publication number CN118629794A discloses a freeze-resistant, highly conductive, and customizable polymer gel electrolyte. This polymer gel electrolyte uses acrylamide as the matrix monomer and achieves synergistic freeze resistance and high conductivity by introducing nanocellulose and sodium alginate to regulate the network structure. Its curing temperature is 50-80℃ and curing time is 2-8h, which is similar to the curing process parameters of this application. However, this polymer gel electrolyte adopts a preparation route of copolymerizing zwitterionic monomers with acrylamide, which is relatively complex. Furthermore, it does not specifically optimize for the suppression of zinc dendrites and interfacial side reactions in aqueous zinc batteries, resulting in insufficient cycle stability in zinc battery systems.

[0005] Patent publication number CN114316305B proposes a hydrogel electrolyte with antifreeze properties. By introducing ethylene glycol and combining it with a freezing method to reconstruct the water network, it achieves stable operation over a wide temperature range of -40-60℃ and possesses compressible and flexible characteristics. However, the antifreeze mechanism of this hydrogel electrolyte relies on the hydrogen bonding effect of ethylene glycol. When the amount of ethylene glycol added is high, it will reduce the ionic conductivity of the electrolyte. At the same time, this electrolyte does not construct a targeted zinc electrode interface protection structure, which cannot effectively inhibit the corrosion and dendrite growth of the zinc anode, making it difficult to break through the low-temperature cycle life of the assembled zinc battery.

[0006] Patent publication number CN118290771B discloses a soybean protein composite gel electrolyte with low hysteresis, low temperature resistance, and fatigue strength. The matrix is ​​formed by copolymerizing soybean protein and acrylamide, and the ion conduction and low-temperature performance are optimized after salt solution treatment. However, the preparation of this soybean protein composite gel electrolyte requires two steps: copolymerization and salt solution soaking. The process is cumbersome and time-consuming. Furthermore, the soybean protein matrix is ​​prone to swelling in high-salt environments, resulting in insufficient structural stability of the electrolyte for long-term use. Moreover, its low-temperature resistance is only suitable for environments above -20°C, failing to meet the requirements of extreme low temperatures.

[0007] In summary, existing patented hydrogel electrolytes have significant shortcomings in terms of preparation process, zinc battery compatibility, and extreme low-temperature tolerance. They are difficult to simultaneously achieve a synergistic improvement in flexible mechanical properties, high electrochemical stability, and wide-temperature range operation. Therefore, there is an urgent need to develop a flexible low-temperature resistant gel electrolyte with a simple preparation process and balanced performance to meet the practical application requirements of aqueous zinc batteries. Summary of the Invention

[0008] To address the shortcomings of existing aqueous zinc-ion batteries using hydrogel electrolytes, such as insufficient mechanical strength, susceptibility to freezing and failure at low temperatures, and inability to effectively suppress zinc dendrite growth and interfacial side reactions, this invention aims to provide a flexible, low-temperature resistant hydrogel electrolyte with a simple preparation method and mild conditions for application in aqueous zinc-ion batteries. By introducing functional additives to reconstruct the hydrogen bond network of water, the mechanical properties, low-temperature resistance, and electrochemical stability of the electrolyte are synergistically improved, providing an ideal electrolyte material for flexible and low-temperature energy storage devices.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] A method for preparing a flexible, low-temperature resistant gel electrolyte includes the following steps:

[0011] S1. Dissolve zinc perchlorate in deionized water and mix thoroughly to obtain a zinc perchlorate electrolyte solution;

[0012] S2. Add acrylamide and N-acetyl-L-glutamine to zinc perchlorate electrolyte solution and stir continuously until acrylamide and N-acetyl-L-glutamine are completely dissolved to obtain a mixture;

[0013] S3. Add the crosslinking agent and initiator to the mixture and continue stirring until the crosslinking agent and initiator are completely dissolved to obtain the hydrogel precursor solution;

[0014] S4. The hydrogel precursor solution is subjected to ultrasonic treatment to remove air bubbles, and the hydrogel solution is then heated and solidified to obtain a flexible, low-temperature resistant gel electrolyte.

[0015] Furthermore, the concentration of the zinc perchlorate electrolyte solution is 0.1-4.0%. .

[0016] Furthermore, the concentration of acrylamide in the mixture is 0.2-2.0%. The concentration of N-acetyl-L-glutamine in the mixture is 0.01-0.95%. .

[0017] Further, the crosslinking agent is N,N'-methylenebisacrylamide, and the amount of crosslinking agent added is 0.5-5‰ of the mass of acrylamide; the initiator is at least one of ammonium persulfate and potassium persulfate, and the amount of initiator added is 1-10‰ of the mass of acrylamide.

[0018] Furthermore, the power of the ultrasonic treatment is 100-300W, and the duration of the ultrasonic treatment is 10-20min.

[0019] Furthermore, the temperature for heat curing is 40-80℃, and the curing time is 3-10 hours.

[0020] The present invention also provides the application of the flexible low-temperature resistant gel electrolyte in aqueous zinc-ion batteries.

[0021] The present invention also provides an aqueous zinc ion electrolyte, which is made of the above-mentioned flexible low-temperature resistant gel electrolyte and is applied in the field of energy storage.

[0022] Furthermore, the positive electrode material of the aqueous zinc-ion battery includes, but is not limited to, one of iodine-based compounds, manganese-based compounds, and vanadium-based compounds, and the negative electrode material of the aqueous zinc-ion battery includes, but is not limited to, one of metallic zinc and zinc-based alloys.

[0023] In this invention, the flexible low-temperature resistant gel electrolyte, through the interaction of N-acetyl-L-glutamine with water molecules and polymer chains, not only reconstructs the hydrogen bond network of water, reducing the activity and freezing point of free water to achieve low-temperature resistance, but also forms dynamic hydrogen bonds with polyacrylamide chains, enhancing the mechanical strength of the electrolyte; at the same time, the three-dimensional cross-linked network can guide the uniform deposition of zinc ions, effectively inhibiting zinc dendrite growth and interfacial side reactions.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The process for preparing gel electrolytes is simple, and the prepared gel electrolytes have good flexibility, tensile strength, puncture resistance and water retention. Its tensile strength is not less than 120 kPa, its puncture resistance is not less than 1.61 N, and its water retention rate at room temperature for 15 days is not less than 92%, which can meet the deformation requirements of flexible electronic devices.

[0026] 2. The prepared gel electrolyte has significantly reduced free water content and activity, enabling dense and uniform zinc ion deposition, effectively inhibiting zinc dendrite formation, improving battery coulombic efficiency and cycle performance, and extending battery life.

[0027] 3. The prepared gel electrolyte can significantly inhibit hydrogen evolution reaction and zinc anode corrosion, broaden the electrochemical stability window of the electrolyte, and ensure the electrochemical safety of the battery.

[0028] 4. The prepared gel electrolyte can form strong hydrogen bond interactions with water molecules, which can effectively destroy the ice crystal structure of aqueous solution. It can still maintain stable ion conduction ability under extreme low temperature environment of -40℃. The assembled Zn / / Zn symmetric cell can cycle stably for more than 2360h at -40℃. The Zn / / Cu half cell has an average coulombic efficiency of no less than 99.42% after 2000 cycles at -20℃, and has excellent low temperature electrochemical reversibility. Attached Figure Description

[0029] Figure 1 Fourier transform infrared spectra of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1.

[0030] Figure 2 The image shows a comparison of the tensile properties of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1.

[0031] Figure 3 The image shows a comparison of puncture tests on the flexible, low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1.

[0032] Figure 4 Comparison of compression tests of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1.

[0033] Figure 5 The graph shows the relationship between the water retention rate and time of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 at 25°C for 15 days.

[0034] Figure 6 This is a comparison chart of the LSV curves of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1.

[0035] Figure 7 This is a cross-sectional scan of the zinc metal negative electrode of the flexible low-temperature resistant gel electrolyte prepared in Example 1.

[0036] Figure 8 This is a cross-sectional scan of the zinc metal negative electrode of the flexible low-temperature resistant gel electrolyte prepared in Comparative Example 1.

[0037] Figure 9 The Zn / / Zn symmetric cell assembled from the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 operates at 1 mA / cm². 2 1mAh / cm 2 Conditional constant current charge and discharge performance.

[0038] Figure 10 The Zn / / Cu half-cell assembled from the flexible, low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 was tested at 2 mA / cm². 2 1mAh / cm 2 Comparison curves of coulomb efficiency under the given conditions.

[0039] Figure 11 The flexible low-temperature resistant gel electrolyte prepared by Example 1 and Comparative Example 1, at -20°C, produces a Zn / / Cu half-cell with a current of 2 mA / cm². 2 1mAh / cm 2 Comparison curves of coulomb efficiency under the given conditions.

[0040] Figure 12 The flexible low-temperature resistant gel electrolyte prepared by Example 1 and Comparative Example 1 achieves a Zn / / Zn symmetric cell at -40°C with a speed of 1 mA / cm. 2 1mAh / cm 2 Conditional constant current charge and discharge performance.

[0041] Figure 13 To implement the cycling performance of a Zn / I2 coin cell at 1 A / g.

[0042] Figure 14 The cycling performance of the Zn / / I2 button cell in Comparative Example 1 is shown at 1 A / g.

[0043] Figure 15 The constant current cycling stability and coulombic efficiency of the Zn / / I2 pouch cell in Example 1 at 0.5 A / g are shown.

[0044] Figure 16 This is an optical image of a pouch cell under external force testing.

[0045] Figure 17 This is a schematic diagram of the preparation steps of a flexible, low-temperature resistant gel electrolyte. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments. The raw materials described in the present invention are all obtained through commercial means. Unless otherwise specified, the preparation methods described in the present invention are conventional preparation methods in the art. The following embodiments are intended to illustrate the present invention and not to further limit the present invention.

[0047] Example 1

[0048] according to Figure 17 The method for preparing the flexible low-temperature resistant gel electrolyte described herein is used to prepare the flexible low-temperature resistant gel electrolyte of Example 1.

[0049] S1. Accurately weigh a certain amount of zinc perchlorate solid and dissolve it in deionized water. Stir magnetically until the zinc perchlorate solid is completely dissolved and the mixture is homogeneous, preparing a solution with a concentration of 2.0. Zinc perchlorate electrolyte solution;

[0050] S2. Add acrylamide and N-acetyl-L-glutamine to the zinc perchlorate electrolyte solution, wherein the amount of acrylamide added is 0.2. The amount of N-acetyl-L-glutamine added was 0.37. Stir magnetically at room temperature for 40 minutes until acrylamide and N-acetyl-L-glutamine are completely dissolved, resulting in a clear and transparent mixture.

[0051] S3. Add N,N'-methylenebisacrylamide and ammonium persulfate to the mixture in sequence, and stir slowly for 30 minutes until the crosslinking agent and initiator are completely dissolved to obtain the hydrogel precursor solution. The amount of N,N'-methylenebisacrylamide added is 2‰ of the mass of acrylamide added in S2, and the amount of ammonium persulfate added is 3‰ of the mass of acrylamide added in S2.

[0052] S4. Place the obtained hydrogel precursor liquid in an ultrasonic cleaner with a power of 150W and sonicate for 15 minutes to completely remove the dissolved gas in the hydrogel precursor liquid. Carefully pour the degassed hydrogel precursor liquid into the mold and transfer the mold to a forced-air drying oven. Heat and cure at 60°C for 4 hours to complete the monomer polymerization and cross-linking curing process of acrylamide. After the reaction is completed, allow it to cool naturally to room temperature. The flexible low-temperature resistant gel electrolyte prepared in Example 1 can then be removed from the mold.

[0053] Comparative Example 1

[0054] Step 1. Accurately weigh a certain amount of zinc perchlorate solid and dissolve it in deionized water. Stir magnetically until the zinc perchlorate solid is completely dissolved and the mixture is homogeneous, preparing a solution with a concentration of 2.0. Zinc perchlorate electrolyte solution;

[0055] Step 2. Add acrylamide to the zinc perchlorate electrolyte solution, wherein the amount of acrylamide added is 0.2 g / L. Stir magnetically at room temperature for 40 minutes until acrylamide and N-acetyl-L-glutamine are completely dissolved, resulting in a clear and transparent mixture.

[0056] Step 3. Add N,N'-methylenebisacrylamide and ammonium persulfate to the mixture in sequence, and stir slowly for 30 minutes until the crosslinking agent and initiator are completely dissolved to obtain the hydrogel precursor solution. The amount of N,N'-methylenebisacrylamide added is 2‰ of the mass of acrylamide added in S2, and the amount of ammonium persulfate added is 3‰ of the mass of acrylamide added in S2.

[0057] Step 4. Place the obtained hydrogel precursor liquid in an ultrasonic cleaner with a power of 150W and sonicate for 15 minutes to completely remove the dissolved gas in the hydrogel precursor liquid. Carefully pour the degassed hydrogel precursor liquid into the mold and transfer the mold to a forced-air drying oven. Heat and cure at 60°C for 4 hours to complete the monomer polymerization and cross-linking curing process of acrylamide. After the reaction is completed, allow it to cool naturally to room temperature. The flexible low-temperature resistant gel electrolyte prepared in Comparative Example 1 can then be removed from the mold.

[0058] like Figure 1 The figure shows the Fourier transform infrared (FTIR) spectra of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1. Compared with Comparative Example 1, the Fourier transform infrared spectrum of Example 1 shows a blue shift after the addition of N-acetyl-L-glutamine, which indicates that the hydrogen bond network of water has changed and the activity of water has decreased.

[0059] like Figure 2 The figure shows a comparison of the tensile properties of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1. The tensile strengths of the gel electrolytes prepared in Example 1 and Comparative Example 1 are 120 kPa and 80 kPa, respectively. This significant reinforcing effect can be attributed to the abundant amide and carboxyl groups in the N-acetyl-L-glutamine molecule. These groups can form a large number of dynamic hydrogen bonds and intermolecular interactions with the amide groups on the polyacrylamide polymer backbone. The additional physical crosslinking points can effectively disperse external stress, enhance the integrity and load-bearing capacity of the polymer network, and thus endow the gel electrolyte with higher mechanical strength.

[0060] like Figure 3 The figure shows a comparison of the puncture test results of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1. Puncture resistance is crucial for hydrogel electrolytes to resist internal dendrite puncture and external concentrated stress of the battery. The flexible low-temperature resistant gel electrolyte of Comparative Example 1 can only withstand a puncture force of 0.275N, while the flexible low-temperature resistant gel electrolyte of Example 1 exhibits excellent puncture resistance and can withstand a puncture force of up to 1.61N.

[0061] like Figure 4 As shown, the compression test comparison diagram of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 is shown. The maximum compressive stress of the flexible low-temperature resistant gel electrolytes in Example 1 and Comparative Example 1 can reach 768 kPa and 310 kPa, respectively. This shows that the gel electrolyte of Example 1 has stronger mechanical reliability and can adapt to complex external force extrusion scenarios.

[0062] like Figure 5 As shown, the graph illustrates the relationship between the water retention rate and time of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 at 25°C for 15 days. After 15 days at room temperature, the flexible low-temperature resistant gel electrolyte of Example 1 can maintain a water retention rate as high as 92.10%, while the flexible low-temperature resistant gel electrolyte of Comparative Example 1 can only retain 76.68% of the water. This indicates that there is a strong binding effect between the water molecules and the hydrophilic functional groups of the polymer in Example 1, which can effectively slow down the rate of evaporation of water molecules from the hydrogel matrix.

[0063] like Figure 6 The figure shows a comparison of the LSV curves of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1. This experiment used linear sweep voltammetry to further evaluate the performance of the flexible low-temperature resistant gel electrolyte in terms of electrochemical stability window. Compared with Comparative Example 1, the flexible low-temperature resistant gel electrolyte of Example 1 exhibited a lower hydrogen evolution reaction current response, which further verified the excellent performance of the flexible low-temperature resistant gel electrolyte of Example 1 in suppressing side reactions. Simultaneously, its oxygen evolution reaction current response was also relatively low, indicating that the overall electrochemical stability of the flexible low-temperature resistant gel electrolyte of Example 1 was enhanced. These performance improvements are mainly attributed to the reduction in free water content within the system and the enhanced interaction between water molecules and the polymer network.

[0064] like Figure 7 and Figure 8The images shown are cross-sectional scans of the zinc metal anodes of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1, respectively. These are the microstructures of the zinc electrode after 100 hours of cycling in a Zn / / Zn symmetric battery assembled from the two flexible low-temperature resistant gel electrolytes under conditions of a current density of 1 mA / cm² and an areal capacity of 1 mAh / cm². The zinc anode surface of Comparative Example 1 is rough and loose, with severe dendrites and corrosion products, while the zinc anode surface of Example 1 is smooth and flat, without dendrites and by-products. This indicates that the flexible low-temperature resistant gel electrolyte of Example 1 successfully suppressed the corrosion reaction and dendrite growth of the zinc anode.

[0065] like Figure 9 The figure shows the constant current charge-discharge performance of Zn / / Zn symmetric batteries assembled from the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 under the conditions of 1 mA / cm² and 1 mAh / cm². Under the same test conditions, the Zn / / Zn symmetric battery of Comparative Example 1 short-circuited after only more than 400 hours of cycling, while the cycle life of the Zn / / Zn symmetric battery of Example 1 was 4 times that of Comparative Example 1. Because the flexible low-temperature resistant gel electrolyte of Example 1 changed the hydrogen bond network of water, it effectively suppressed the corrosion reaction and guided the uniform deposition of zinc ions in the electrochemical cycle, inhibiting the growth of zinc dendrites, and finally achieved stable cycling of Zn / / Zn symmetric batteries for more than 1600 hours.

[0066] like Figure 10 As shown in the figure, the coulombic efficiency comparison curves of Zn / / Cu half-cells assembled with the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 are shown under the conditions of 2 mA / cm² and 1 mAh / cm². As can be seen from the figure, the cycle life of the Zn / / Cu half-cell assembled with the flexible low-temperature resistant gel electrolyte in Comparative Example 1 is significantly lower than that in Example 1. The Zn / / Cu half-cell in Example 1 can cycle stably for 550 cycles with an average coulombic efficiency of 99.35%, indicating that the electrochemical performance of the Zn / / Cu half-cell is significantly improved under the action of the flexible low-temperature resistant gel electrolyte in Example 1.

[0067] like Figure 11 As shown, the coulombic efficiency curves of the flexible low-temperature resistant gel electrolytes prepared in Example 1 and Comparative Example 1 at -20℃ for Zn / / Cu half-cells under the conditions of 2mA / cm² and 1mAh / cm² are compared. The Zn / / Cu half-cell assembled with the flexible low-temperature resistant gel electrolyte of Example 1 can stably cycle for 2000 cycles with an average coulombic efficiency of 99.42%. This data fully demonstrates that even in the low-temperature environment of -20℃, the flexible low-temperature resistant gel electrolyte of Example 1 can still effectively suppress dendrite growth and interfacial side reactions, ensuring the high reversibility of zinc ion deposition and stripping processes.

[0068] like Figure 12The figure shows the constant current charge-discharge performance of the flexible low-temperature resistant gel electrolyte prepared by Example 1 and Comparative Example 1 at -40°C under the conditions of 1 mA / cm² and 1 mAh / cm². The Zn / / Zn symmetric battery assembled with the flexible low-temperature resistant gel electrolyte of Example 1 can stably cycle for more than 2360 hours without short circuit in the extreme low temperature environment of -40°C. This proves that the electrolyte can continuously and effectively suppress the growth of zinc dendrites under this harsh condition, providing a solid and reliable electrolyte solution for the practical application of aqueous zinc-ion batteries in extreme low temperature environments such as cold regions, high-altitude exploration, and winter outdoor equipment.

[0069] like Figure 13 The figure shows the cycling performance of the Zn / / I2 coin cell prepared by the flexible low-temperature resistant gel electrolyte of Example 1 at 1A / g. After 1000 cycles at 1A / g, the coulombic efficiency of the Zn / / I2 coin cell of Example 1 is close to 100%, and the specific capacity is 167mAh / g; while this performance is difficult to achieve in the Zn / / I2 coin cell of Comparative Example 1.

[0070] like Figure 14 The figure shows the cycling performance of the Zn / / I2 coin cell prepared by the flexible low-temperature resistant gel electrolyte of Comparative Example 1 at 1A / g. The specific capacity of the Zn / / I2 coin cell of Comparative Example 1 drops rapidly, and the specific capacity drops to 0mAh / g after 223 cycles at 1A / g.

[0071] like Figure 15 As shown, the constant current cycling stability and coulombic efficiency of the Zn / / I2 pouch cell prepared by the flexible low-temperature resistant gel electrolyte of Example 1 are displayed at a current density of 0.5 A / g. The Zn / / I2 pouch cell still retains a high capacity after 400 cycles, showing excellent cycling stability.

[0072] like Figure 16 The image shown is an optical image "XJU" of the Zn / / I2 pouch battery prepared by the flexible low-temperature resistant gel electrolyte of Example 1 under external force testing. When the flexible low-temperature resistant gel electrolyte of Example 1 is applied to a flexible battery system, the battery can maintain a stable voltage under extreme test conditions such as bending, freezing, hammering, and shearing, proving that it can meet the stringent requirements of flexible and special-shaped electronic devices.

[0073] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A method for preparing a flexible, low-temperature resistant gel electrolyte, characterized in that, Includes the following steps: S1. Dissolve zinc perchlorate in deionized water and mix thoroughly to obtain a zinc perchlorate electrolyte solution; S2. Add acrylamide and N-acetyl-L-glutamine to zinc perchlorate electrolyte solution and stir continuously until acrylamide and N-acetyl-L-glutamine are completely dissolved to obtain a mixture; S3. Add the crosslinking agent and initiator to the mixture and continue stirring until the crosslinking agent and initiator are completely dissolved to obtain the hydrogel precursor solution; S4. The hydrogel precursor solution is subjected to ultrasonic treatment to remove air bubbles, and the hydrogel solution is then heated and solidified to obtain a flexible, low-temperature resistant gel electrolyte.

2. The method for preparing a flexible low-temperature resistant gel electrolyte according to claim 1, characterized in that, The concentration of the zinc perchlorate electrolyte solution is 0.1-4.0%. .

3. The method for preparing a flexible low-temperature resistant gel electrolyte according to claim 1, characterized in that, The concentration of acrylamide is 0.2-2.0%. The concentration of the N-acetyl-L-glutamine is 0.01-0.95%. .

4. The method for preparing a flexible low-temperature resistant gel electrolyte according to claim 1, characterized in that, The crosslinking agent is N,N'-methylenebisacrylamide, and the amount of crosslinking agent added is 0.5-5‰ of the mass of acrylamide; the initiator is at least one of ammonium persulfate and potassium persulfate, and the amount of initiator added is 1-10‰ of the mass of acrylamide.

5. The method for preparing a flexible low-temperature resistant gel electrolyte according to claim 1, characterized in that, The ultrasonic treatment power is 100-300W, and the ultrasonic treatment duration is 10-20min.

6. The method for preparing a flexible low-temperature resistant gel electrolyte according to claim 1, characterized in that, The heating and curing temperature is 40-80℃, and the heating and curing time is 3-10 hours.

7. The method for preparing a flexible low-temperature resistant gel electrolyte according to claim 1, characterized in that, Application of the flexible low-temperature resistant gel electrolyte in aqueous zinc-ion batteries.

8. The application according to claim 6, characterized in that, The positive electrode material of the aqueous zinc-ion battery includes, but is not limited to, one of iodine, manganese-based compounds, and vanadium-based compounds, and the negative electrode material of the aqueous zinc-ion battery includes, but is not limited to, one of metallic zinc and zinc-based alloys.

9. The application according to claim 6, characterized in that, The application of aqueous zinc-ion batteries in the field of energy storage.

Images