A dual-network self-healing hydrogel electrolyte, a preparation method thereof and a water-based zinc ion battery

Abstract

The application discloses a preparation method of a double-network self-healing hydrogel electrolyte, and comprises the following steps: dissolving a quaternary ammonium polymer and a crosslinking agent in a zinc salt solution, ultrasonic stirring and dissolving until transparent, dropping glacial acetic acid to adjust the pH to 4-6, heating and stirring at 45-55 DEG C for 2-4 h to prepare a solution, adding an anionic monomer and acrylamide after cooling to room temperature, stirring, adding an initiator under ice bath and nitrogen protection, stirring and dissolving, removing bubbles by ultrasonic, and free radical polymerization at 55-65 DEG C for 1-4 h to form a gel. The application further discloses the double-network self-healing hydrogel electrolyte prepared by the above preparation method and a water-based zinc ion battery. The hydrogel electrolyte prepared by the application has high super tensile property and high conductivity, and has good self-healing ability, and exhibits super long cycle stability when applied to a water-based zinc ion battery, and can stably supply power even under extremely harsh conditions in a flexible water-based zinc ion battery.

Description

Technical Field

[0001] This invention relates to the field of solid electrolytes for zinc-ion batteries, and particularly to a dual-network self-healing hydrogel electrolyte, its preparation method, and an aqueous zinc-ion battery. Background Technology

[0002] Lithium-ion batteries have attracted significant attention due to their high energy density and good cycle stability. However, their flammability and explosiveness pose a major challenge to their application in flexible electronic devices that require repeated folding. Therefore, safe, inexpensive, and resource-rich aqueous zinc-ion batteries (ZIBs) have become a focus of research, with the potential to replace lithium-ion batteries in flexible electronic devices. However, the solvation structure of zinc ions in aqueous ZIBs leads to severe zinc dendrite formation and side reactions, resulting in poor cycle stability and reduced coulombic efficiency, hindering their development.

[0003] Hydrogel electrolytes can improve the cycling stability of zinc ions (ZIBs) by introducing various functional groups to immobilize free water and disrupt the solvation structure of zinc ions. However, existing hydrogel electrolytes often require cumbersome soaking steps, or lack sufficient ability to suppress zinc dendrites and side reactions, resulting in poor mechanical properties and hindering their application in flexible aqueous zinc-ion batteries. Chinese invention patent CN 114195935 A uses 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and acrylic acid dissolved in a zinc salt solution to prepare a polyanionic zinc salt hydrogel electrolyte after polymerization. While the method is simple, it only achieves stability for less than 400 hours in zinc symmetric batteries, exhibiting weak ability to suppress zinc dendrites and side reactions. Chinese invention patent CN 116574274 A uses a complex sugar of polysaccharides and disaccharides to crosslink with zinc ions to form a hydrogel electrolyte with good capacity retention, but requires a cumbersome soaking step and has poor tensile properties, making it unsuitable for flexible aqueous zinc-ion batteries requiring repeated folding. Therefore, developing hydrogel electrolytes with both high electrochemical performance and good mechanical properties remains a challenge. Summary of the Invention

[0004] To overcome the aforementioned shortcomings and deficiencies of the prior art, the present invention aims to provide a method for preparing a dual-network self-healing hydrogel electrolyte. This method is simple and, compared to traditional hydrogel electrolytes which require soaking, simplifies the process and facilitates industrialization. Furthermore, it allows for the preparation of Zn... 2+ It is more evenly distributed in hydrogel electrolytes; at the same time, it can effectively suppress the formation of zinc dendrites and side reactions.

[0005] Another objective of this invention is to provide a dual-network self-healing hydrogel electrolyte with excellent tensile properties and good self-healing properties, suitable for wearable flexible aqueous zinc-ion batteries.

[0006] Another object of the present invention is to provide an aqueous zinc-ion battery, in 1Ag -1 At current density, it can still retain 81.47% of its capacity after 1500 cycles, and can still provide stable power supply even under harsh conditions such as bending, folding, hammering, twisting, and even puncturing.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a dual-network self-healing hydrogel electrolyte includes the following steps:

[0009] The quaternized polymer and crosslinking agent were dissolved in a zinc salt solution and ultrasonically stirred until transparent. Glacial acetic acid was added dropwise to adjust the pH to 4-6. The solution was heated and stirred at 45-55℃ for 2-4 hours to prepare a solution. After cooling to room temperature, anionic monomer and acrylamide were added and stirred evenly. The initiator was added under ice bath and nitrogen protection. After stirring and dissolving, the bubbles were removed by ultrasonication. Free radical polymerization was carried out at 55-65℃ for 1-4 hours to form a gel.

[0010] The quaternized polymer is at least one of quaternized chitosan, quaternized gelatin, and quaternized polyethyleneimine;

[0011] The crosslinking agent is one of glutaraldehyde, glyoxal, and succinal.

[0012] The anionic monomer is one of sodium acrylate, sodium methacrylate, sodium itaconic acid, and potassium acrylate;

[0013] The initiator is one of potassium sulfate, sodium persulfate, ammonium persulfate, or azobisisobutyramidine hydrochloride.

[0014] Preferably, the mass ratio of the quaternized polymer to acrylamide is (0.05-0.25):1.

[0015] Preferably, the mass ratio of the anionic monomer to the quaternized polymer is (0.8-1.2):1.

[0016] Preferably, the mass ratio of the initiator to acrylamide is (0.005-0.015):1.

[0017] Preferably, the mass-volume ratio of the quaternized polymer to the crosslinking agent is (0.4-2)g:(10-60)uL.

[0018] Preferably, the zinc salt is one of zinc chloride, zinc sulfate, zinc trifluoromethanesulfonate, zinc acetate, and zinc perchlorate.

[0019] A dual-network self-healing hydrogel electrolyte is prepared by the method described above.

[0020] Aqueous zinc-ion batteries, including the aforementioned dual-network self-healing hydrogel electrolyte.

[0021] Preferably, the aqueous zinc-ion battery comprises a zinc sheet negative electrode, a hydrogel electrolyte, and H2O. + Carbon cloth cathode doped with polyaniline.

[0022] Preferably, the aqueous zinc-ion battery is a wearable flexible aqueous zinc-ion battery.

[0023] The principle of this invention is as follows:

[0024] This invention introduces dynamic covalent bonds—imine bonds—into the hydrogel electrolyte through a Schiff base reaction between an aldehyde crosslinking agent and the amino groups on a quaternized polymer. This results in a hydrogel electrolyte with excellent self-healing properties. The introduced quaternized polymer and anionic monomers provide various non-covalent interactions for the hydrogel, giving it good mechanical properties. Simultaneously, the introduction of cations and anions establishes uninterrupted ion transport channels, improving conductivity, and immobilizes free water, disrupting the solvation structure of zinc ions, thereby inhibiting zinc dendrite growth and side reactions, and ultimately improving the cycling stability of ZIBs. The self-healing ability and good mechanical properties of the hydrogel electrolyte enhance its anti-interference capabilities when applied to flexible aqueous zinc-ion batteries, allowing flexible ZIBs to provide stable power supply even under harsh conditions.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) The dual-network self-healing hydrogel electrolyte prepared in this invention exhibits excellent cycling stability when applied to ZIBs, demonstrating a stable cycling voltage of 1400 h in a Zn||Zn symmetric cell. When used in a full cell, it achieves a stable voltage of 1 Ag. -1 At current density, it retains 81.47% of its capacity after 1500 cycles.

[0027] (2) The dual-network self-healing hydrogel electrolyte prepared by the present invention has excellent tensile properties and good self-healing properties, so that it will not be mechanically broken when applied to flexible aqueous zinc-ion batteries that need to be repeatedly folded, and can recover even if it is broken.

[0028] (3) The dual-network self-healing hydrogel electrolyte prepared in this invention can still provide stable power supply even under harsh conditions such as bending, folding, hammering, twisting, and even puncturing when applied to flexible aqueous zinc-ion batteries.

[0029] (4) This invention is simple to prepare and conducive to industrialization. This invention prepares hydrogel electrolytes by dissolving all the reactants in a zinc salt solution, which simplifies the process compared to traditional hydrogel electrolytes that require soaking. This simplifies the process and facilitates industrialization. Furthermore, it allows for the efficient processing of Zn... 2+ It is more evenly distributed in hydrogel electrolytes. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the synthesis route of the dual-network self-healing hydrogel electrolyte in Embodiment 1 of the present invention.

[0031] Figure 2 The image shows the tensile curve of the dual-network self-healing hydrogel electrolyte of Example 1 of the present invention.

[0032] Figure 3 The image shows the double-network self-healing hydrogel electrolyte of Example 1 of the present invention cut in half, one half stained with rhodamine b, and then self-healed at room temperature for 1 day.

[0033] Figure 4 To construct Zn||Zn symmetric cells using the dual-network self-healing hydrogel electrolyte of Example 1 of the present invention and the comparative example as electrolytes, respectively, at a current density of 0.5 mA / cm², 2 Voltage-time curve under [condition].

[0034] Figure 5 for Figure 4 The voltage-time curve of the local amplification after about 200 hours of cycling.

[0035] Figure 6 for Figure 4 The voltage-time curve of local amplification after approximately 1000 hours of cycling.

[0036] Figure 7 Using the dual-network self-healing hydrogel electrolyte of the comparative example (left) and Example 1 of the present invention (right) as the electrolyte for a Zn||Zn symmetric battery, at a high current density of 2 mA / cm²... 2 SEM image of the zinc sheet after 50 cycles.

[0037] Figure 8 The diagram shows the long-cycle performance of a full cell composed of the dual-network self-healing hydrogel electrolyte of Example 1 of the present invention and the electrolyte of the comparative example.

[0038] Figure 9 Figures show the stable power supply under different harsh conditions when using the dual-network self-healing hydrogel electrolyte of Example 1 of the present invention as the electrolyte to form a flexible aqueous zinc-ion battery. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0040] In the following embodiments, unless otherwise specified, the performance of the hydrogel electrolyte was tested using the following methods:

[0041] (1) Conductivity test: The hydrogel electrolyte is sandwiched between two copper plates, and the resistance is measured using the EIS tester of the electrochemical workstation. The conductivity is calculated using the following formula.

[0042] σ = l / RAl is the thickness of the hydrogel electrolyte, R is the volume resistivity measured by EIS, and A is the area of ​​the hydrogel electrolyte.

[0043] (2) Tensile property test: The rectangular hydrogel electrolyte sample was tested on the KJ-1065A-T tensile strength tester at room temperature. The actual measured length of the sample was 10 mm, the thickness was 1 mm, the width was 4 mm, and the tensile rate was 50 mm / min.

[0044] (3) Hydrogel electrolyte healing test (visual observation): The prepared hydrogel electrolyte was cut into two halves, one half was stained with rhodamine, and then the two pieces of hydrogel electrolyte were brought close to each other and left to stand at room temperature for 1 day. Then, the two ends were pinched and pulled with tweezers. It can be observed that the hydrogel electrolyte did not break.

[0045] Example 1

[0046] A method for preparing a dual-network self-healing hydrogel electrolyte includes the following steps:

[0047] Dissolve 0.8 g of quaternized chitosan and 20 μL of crosslinking agent in 40 mL of 2 M zinc sulfate solution. Stir ultrasonically until the solution is transparent. Add glacial acetic acid to adjust the pH to 4-6. Heat and stir at 50 °C for 3 h to prepare a solution. After cooling to room temperature, add 0.8 g of sodium acrylate and 8 g of acrylamide. Stir well. Add 0.08 g of potassium persulfate under ice bath and nitrogen protection. Stir to dissolve and remove bubbles by ultrasonication. Free radical polymerization at 60 °C for 2 h to form a gel.

[0048] The ionic conductivity calculated from the volume resistivity obtained by EIS testing in this embodiment is 33.61 mS / cm, which is higher than the 22.43 mS / cm in Chinese Invention Patent Publication CN 116574274 A. This is because the introduced quaternized chitosan and sodium acrylate anions and cations establish an interference-free ion transport channel within the hydrogel. Figure 2 It can be seen that the ultimate tensile stress in this embodiment is 77 kPa and the ultimate tensile strain is 5170%, which is much higher than the 40% in Chinese invention patent publication CN 116574274A. This is because quaternized chitosan is introduced to construct a double network structure, and the introduced carboxylate groups react with Zn.2+ A strong complexation reaction occurs, providing energy dissipation for the hydrogel electrolyte. Figure 3 It can be seen that this embodiment also has good self-healing ability.

[0049] Zinc-zinc symmetric batteries consist of a negative zinc electrode, a positive zinc electrode, and an electrolyte. Aqueous zinc-ion full batteries consist of a positive electrode material (H... + The electrolyte consists of polyaniline-doped carbon cloth, a negative electrode material (zinc sheet), and an electrolyte. The comparative example uses a 2M ZnSO4 electrolyte, while Example 1 uses a hydrogel electrolyte. The cells were assembled into a button cell, and the battery performance was tested as follows:

[0050] Depend on Figures 4-6 It can be seen that in the comparative example of zinc-zinc symmetric cells, 0.5 mA / cm 2 The stable cycling time at the specified current density was less than 150 hours, far lower than the 1400 hours of Example 1, indicating that Example 1 can effectively suppress zinc dendrites and side reactions, thus exhibiting better cycling stability. Figure 7 SEM images of the zinc sheet also confirmed this. Figure 8 It can be seen that, in the comparative example, under a high current density of 1 A / g in the full cell, the capacity can only be maintained at 53.27% after 1500 cycles, which is far lower than the 81.47% in Example 1.

[0051] In the zinc-zinc symmetric battery, Example 1 can stably cycle for over 1400 hours, far exceeding the 350 hours reported in Chinese Invention Patent CN114195935 A, indicating its excellent ability to suppress zinc dendrites and side reactions. In the full cell, at a high current density of 1 A / g, after 1500 stable cycles, the capacity still retains 81.47%, with a single-cycle capacity loss rate of 0.012%, which is far better than the 82.4% capacity retention and 0.088% single-cycle capacity loss rate reported in Chinese Invention Patent CN 114195935 A after 200 cycles.

[0052] Depend on Figure 9 It can be seen that the brightness of the bulb remains basically unchanged under various harsh conditions (pressing, bending, folding, knocking, puncturing) in the flexible aqueous zinc-ion battery, indicating that it can provide stable power supply.

[0053] Example 2

[0054] A method for preparing a dual-network self-healing hydrogel electrolyte includes the following steps:

[0055] Dissolve 0.4 g of quaternized chitosan and 10 μL of glyoxal in 40 mL of 2 M zinc chloride solution. Stir ultrasonically until the solution is transparent. Add glacial acetic acid to adjust the pH to 4-6. Heat and stir at 50 °C for 2 h to prepare a solution. After cooling to room temperature, add 0.4 g of potassium acrylate and 8 g of acrylamide. Stir well. Add 0.04 g of ammonium persulfate under ice bath and nitrogen protection. Stir to dissolve and remove bubbles by ultrasonication. Free radical polymerization is carried out at 60 °C for 4 h to form a gel.

[0056] The ionic conductivity of this embodiment is 28.12 mS / cm, and the tensile strain can reach 4621%. When assembled into an aqueous zinc-ion battery according to Example 1, the capacity retention rate is 78.31% after 1500 cycles at a current density of 1 A / g in the full cell.

[0057] Example 3

[0058] A method for preparing a dual-network self-healing hydrogel electrolyte includes the following steps:

[0059] Dissolve 2g of quaternized gelatin and 60uL of succinate in 40mL of 2M zinc trifluoromethanesulfonate solution. Stir ultrasonically until the solution is transparent. Add glacial acetic acid to adjust the pH to 4-6. Heat and stir at 50℃ for 4h to prepare a solution. After cooling to room temperature, add 2g of sodium methacrylate and 8g of acrylamide. Stir well. Add 0.12g of sodium persulfate under ice bath and nitrogen protection. Stir to dissolve and remove bubbles by ultrasonication. Perform free radical polymerization at 60℃ for 1h to form a gel.

[0060] The ionic conductivity of this embodiment is 14.87 mS / cm, and the tensile strain can reach 1651%. When assembled into an aqueous zinc-ion battery according to Example 1, the capacity retention rate is 69.42% after 1500 cycles at a current density of 1 A / g in the full cell.

[0061] Example 4

[0062] A method for preparing a dual-network self-healing hydrogel electrolyte includes the following steps:

[0063] Dissolve 1.2g of quaternized gelatin and 40uL of glyoxal in 40mL of 2M zinc perchlorate solution. Sonicate the solution until transparent. Add glacial acetic acid to adjust the pH to 4-6. Heat and stir at 50℃ for 2h to prepare a solution. After cooling to room temperature, add 1.2g of sodium itaconic acid and 8g of acrylamide. Stir well. Add 0.08g of azobisisobutyramidine hydrochloride under ice bath and nitrogen protection. Stir to dissolve and remove air bubbles by sonication. Perform free radical polymerization at 60℃ for 3h to form a gel.

[0064] The ionic conductivity of this embodiment is 24.36 mS / cm, and the tensile strain can reach 3407%. When assembled into an aqueous zinc-ion battery according to Example 1, the capacity retention rate is 75.25% after 1500 cycles at a current density of 1 A / g in the full cell.

[0065] Example 5

[0066] A method for preparing a dual-network self-healing hydrogel electrolyte includes the following steps:

[0067] Dissolve 1.6 g of quaternized polyethyleneimine and 30 μL of glutaraldehyde in 40 mL of 2 M zinc acetate solution. Stir the solution with ultrasound until it becomes transparent. Add glacial acetic acid to adjust the pH to 4-6. Heat and stir at 50 °C for 3 h to prepare a solution. After cooling to room temperature, add 1.6 g of sodium acrylate and 8 g of acrylamide. Stir well. Add 0.1 g of potassium persulfate under ice bath and nitrogen protection. Stir to dissolve and remove bubbles with ultrasound. Free radical polymerization is carried out at 60 °C for 2 h to form a gel.

[0068] The ionic conductivity of this embodiment is 20.64 mS / cm, and the tensile strain can reach 2356%. When assembled into an aqueous zinc-ion battery according to Example 1, the capacity retention rate is 71.84% after 1500 cycles at a current density of 1 A / g in the full cell.

[0069] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a dual-network self-healing hydrogel electrolyte, characterized in that, Includes the following steps: The quaternized polymer and crosslinking agent were dissolved in a zinc salt solution and ultrasonically stirred until transparent. Glacial acetic acid was added dropwise to adjust the pH to 4-6. The solution was heated and stirred at 45-55℃ for 2-4 hours to prepare a solution. After cooling to room temperature, anionic monomer and acrylamide were added and stirred evenly. The initiator was added under ice bath and nitrogen protection. After stirring and dissolving, the bubbles were removed by ultrasonication. Free radical polymerization was carried out at 55-65℃ for 1-4 hours to form a gel. The quaternized polymer is at least one of quaternized chitosan, quaternized gelatin, and quaternized polyethyleneimine; The crosslinking agent is one of glutaraldehyde, glyoxal, and succinal. The anionic monomer is one of sodium acrylate, sodium methacrylate, sodium itaconic acid, and potassium acrylate; The initiator is one of potassium sulfate, sodium persulfate, ammonium persulfate, or azobisisobutyramidine hydrochloride.

2. The preparation method of the dual-network self-healing hydrogel electrolyte according to claim 1, characterized in that, The mass ratio of the quaternized polymer to acrylamide is (0.05-0.25):

1.

3. The method for preparing the dual-network self-healing hydrogel electrolyte according to claim 1 or 2, characterized in that, The mass ratio of the anionic monomer to the quaternized polymer is (0.8-1.2):

1.

4. The method for preparing the dual-network self-healing hydrogel electrolyte according to claim 1, characterized in that, The mass ratio of the initiator to acrylamide is (0.005-0.015):

1.

5. The method for preparing the dual-network self-healing hydrogel electrolyte according to claim 1, characterized in that, The mass-volume ratio of the quaternized polymer to the crosslinking agent is (0.4-2) g : (10-60) uL.

6. The method for preparing the dual-network self-healing hydrogel electrolyte according to claim 1, characterized in that, The zinc salt is one of zinc chloride, zinc sulfate, zinc trifluoromethanesulfonate, zinc acetate, and zinc perchlorate.

7. A dual-network self-healing hydrogel electrolyte, characterized in that, It is prepared by the method for preparing the dual-network self-healing hydrogel electrolyte according to any one of claims 1-6.

8. An aqueous zinc-ion battery, characterized in that, Includes the dual-network self-healing hydrogel electrolyte as described in claim 7.

9. The aqueous zinc-ion battery according to claim 8, characterized in that, Including zinc sheet negative electrode, hydrogel electrolyte and H + Carbon cloth cathode doped with polyaniline.

10. The aqueous zinc-ion battery according to claim 8, characterized in that, It is a wearable, flexible, aqueous zinc-ion battery.

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