A method for preparing sodium polyacrylate hydrogel containing covalent organic framework material by in situ polymerization

Abstract

The present invention provides a method for preparing a sodium polyacrylate hydrogel containing a covalent organic framework material by in-situ polymerization. First, the crosslinking agent N,N'-methylenebisacrylamide is dissolved in acrylic acid and neutralized with sodium hydroxide solution to obtain a sodium acrylate solution. Potassium hydroxide and zinc acetate are dissolved in water and then poured into the sodium acrylate solution and stirred to mix evenly. The covalent organic framework material TpPa (SO3H) is then added and stirred to disperse evenly. Finally, the initiator ammonium persulfate is added. After completion, the solution is poured into a mold and allowed to stand for gel polymerization to obtain a hydrogel electrolyte.

Description

Technical Field

[0001] This invention relates to the preparation of polymer hydrogel membranes and gel electrolytes, and is applied to the field of green energy storage devices, represented by rechargeable metal-based batteries. Background Technology

[0002] With rapid societal development, zinc-based batteries have become a promising option for advanced energy storage devices due to their high energy density, safety, environmental friendliness, and cost-effectiveness. Flexible zinc-based batteries, including flexible zinc-air batteries (FAZABs), offer advantages such as high flexibility, wearability, safety, and a low risk of electrolyte leakage, making them highly promising for wearable and implantable electronic devices. For batteries, the electrolyte system, as the ion conductor connecting the anode and cathode, determines the mass transfer and interfacial chemistry throughout the charge-discharge process, and is crucial to the overall performance of ZABs (e.g., energy density, rechargeability, and operating voltage).

[0003] Gel electrolytes (GPEs) consist of two parts: a polymer matrix and an electrolyte, combining the advantages of both liquid and solid electrolytes. Compared to liquid electrolytes, GPEs endow ZABs with portability, flexibility, and wearability. They also play a significant role in preventing electrolyte leakage, stabilizing the three-phase interface, and suppressing zinc dendrite formation. However, the use of GPEs in FAZABs presents the following problems: (a) Compared to liquid electrolytes, polymer electrolytes exhibit lower ionic conductivity. (b) The semi-open structure of the battery accelerates moisture loss from the GPEs, leading to battery failure. (c) During battery cycling, the interface between the zinc anode and the electrolyte is unstable, easily resulting in dendrite formation. Therefore, it is necessary to improve GPEs to enhance their conductivity, mechanical stability, and alkali resistance, thereby increasing battery life. Introducing covalent organic framework (COF) materials into GPEs, such as sulfonic acid groups and carboxyl groups modified on the COFs, can form hydrogen bonds with the polymer chains, thereby improving the water retention and mechanical properties of GPEs. In addition, sulfonic acid groups can induce uniform zinc deposition, which has great potential for optimizing GPEs. Summary of the Invention

[0004] To address the aforementioned issues, this invention introduces COF material during the in-situ polymerization of sodium polyacrylate. The modified groups on the COF can form hydrogen bonds with the sodium polyacrylate molecular chains and water molecules, resulting in a gel electrolyte with high ionic conductivity and electrolyte retention capacity. Simultaneously, the modification with sulfonic acid groups can induce uniform zinc deposition, inhibiting zinc plate corrosion and dendrite formation. This technology is intended for application in rechargeable flexible zinc-air batteries, providing a stable and uniform electrode / electrolyte interface for the zinc anode and achieving a long cycle life for the zinc-air battery.

[0005] In view of this, the present invention provides a method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material through in-situ polymerization, the preparation of which includes the following steps:

[0006] Step 1: Preparation of Sodium Acrylate Solution: First, dissolve sodium hydroxide in water and N,N'-methylenebisacrylamide in acrylic acid, stirring separately to obtain uniformly dispersed solutions. The purpose of this step is to ensure that sodium hydroxide and N,N'-methylenebisacrylamide are uniformly dispersed in the water and acrylic acid solutions respectively, facilitating subsequent uniform mixing of the two solutions. Slowly add the sodium hydroxide solution dropwise to the acrylic acid solution containing N,N'-methylenebisacrylamide while continuing to stir to obtain a neutralized sodium acrylate solution.

[0007] In some embodiments, the concentration of sodium hydroxide is 5-10 mol / L, the concentration of the crosslinking agent N,N'-methylenebisacrylamide in the acrylic acid solution is 30-40 mg / mL, and the molar ratio of sodium hydroxide to acrylic acid is 1:1.0-1.10.

[0008] The temperature for magnetic stirring of the sodium acrylate solution is 0~10℃.

[0009] This is to obtain a neutralized sodium acrylate solution. The cold water bath, strong magnetic stirring, and slow dripping of sodium hydroxide solution are to avoid the explosive polymerization of acrylic acid caused by the large amount of heat released during the neutralization reaction.

[0010] Step 2: Preparation of potassium hydroxide / zinc salt / sodium acrylate mixed solution: Dissolve potassium hydroxide and zinc acetate in water and stir magnetically to obtain a uniform dispersion. Then add the prepared sodium acrylate solution to the potassium hydroxide / zinc acetate solution and stir to disperse evenly.

[0011] In some implementations, the concentration of potassium hydroxide is 5-8 mol / L, and the concentration of zinc salt is 0.1-0.5 mol / L.

[0012] Zinc salts include any one of zinc acetate, zinc sulfate, zinc chloride, zinc oxalate, and zinc nitrate.

[0013] Step 3: Preparation of the sodium acrylate mixed solution containing covalent organic framework material (COF): Add the COF material to the prepared sodium acrylate solution and stir to disperse it evenly. The purpose of this step is to ensure that the mixed solution and COF material are mixed evenly.

[0014] The covalent organic framework material (COF material) is selected from any one of TpPa(SO3H), TpPa(COOH), TpBD(SO3H)2, and TpBD(COOH)2.

[0015] In some implementations, the concentration of the covalent organic framework material in the solution is 0.12–0.36 mg / mL.

[0016] Step 4: Preparation of sodium polyacrylate hydrogel containing covalent organic framework material: Add a certain amount of initiator ammonium persulfate to the above solution, then pour the solution into a mold and let it stand for gel polymerization. After step 3, sodium acrylate, crosslinking agent, potassium hydroxide, zinc acetate, and COF material are uniformly dispersed. Adding an initiator under these conditions will help form a more uniform structure.

[0017] In some embodiments, the concentration of the initiator ammonium persulfate in the mixed solution is 1-2 mg / mL, and the standing time is 10-20 min.

[0018] The initiator ammonium persulfate induces the free radical polymerization of sodium acrylate monomers to form sodium acrylate chains. These sodium acrylate chains further react with an N,N'-methylenebisacrylamide crosslinking agent to form a sodium polyacrylate polymer. Simultaneously, the carboxylic acid groups on the sodium acrylate chains form hydrogen bonds through water molecules and the N and O atoms on the COF surface, thereby forming a crosslinked polymer. The battery assembled using the technical solution of this application has a power density of 200 mW / cm³. -2 The above; further optimization can reach 230 mW / cm². -2 The above; further optimization can reach 200 mW / cm. -2 The battery cycle life is above 50 hours, preferably above 80 hours, preferably above 100 hours, and preferably above 120 hours. Attached Figure Description

[0019] Figure 1 The diagram shows the structures of the six COF materials used.

[0020] Figure 2 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 1 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample of Example 1 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown, where (a) is the electrochemical impedance spectroscopy (EIS), (b) is the rate capability, (c) is the open-circuit voltage, (d) is the discharge polarization curve and the corresponding power density, and (e) is the discharge voltage at 1 mA / cm². -2 The constant current charge-discharge curve at that time.

[0021] Figure 3 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 2 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample of Example 2 are measured at 1 mA cm⁻¹.-2 The constant current charge-discharge curves are shown, where (a) is the electrochemical impedance spectroscopy (EIS), (b) is the rate capability, (c) is the open-circuit voltage, (d) is the discharge polarization curve and the corresponding power density, and (e) is the discharge voltage at 1 mA / cm². -2 The constant current charge-discharge curve at that time.

[0022] Figure 4 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 3 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample of Example 3 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown, where (a) is the electrochemical impedance spectroscopy (EIS), (b) is the rate capability, (c) is the open-circuit voltage, (d) is the discharge polarization curve and the corresponding power density, and (e) is the discharge voltage at 1 mA / cm². -2 The constant current charge-discharge curve at that time.

[0023] Figure 5 The open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample prepared in Example 4 were measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown, where (a) is the open-circuit voltage, (b) is the rate, (c) is the discharge polarization curve and the corresponding power density, and (d) is the discharge rate at 1 mA cm⁻¹. -2 The constant current charge-discharge curve at that time.

[0024] Figure 6 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 5 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample in Example 5 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown, where (a) is the electrochemical impedance spectroscopy (EIS), (b) is the rate capability, (c) is the open-circuit voltage, (d) is the discharge polarization curve and the corresponding power density, and (e) is the discharge voltage at 1 mA / cm². -2 The constant current charge-discharge curve at that time.

[0025] Figure 7 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 6 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample of Example 6 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown, where (a) is the electrochemical impedance spectroscopy (EIS), (b) is the rate capability, (c) is the open-circuit voltage, (d) is the discharge polarization curve and the corresponding power density, and (e) is the discharge voltage at 1 mA / cm². -2 The constant current charge-discharge curve at that time.

[0026] Figure 8 The open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample prepared in Example 7 were measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown, where (a) is the open-circuit voltage, (b) is the rate, (c) is the discharge polarization curve and the corresponding power density, and (d) is the discharge rate at 1 mA cm⁻¹. -2 The constant current charge-discharge curve at that time. Detailed Implementation

[0027] Characterization conditions

[0028] In this embodiment of the invention, the electrochemical impedance spectroscopy (EIS) was measured using a Shanghai Chenhua workstation. The testing method was as follows: a certain thickness ( T Cut the hydrogel into 1 cm wide pieces. W ), 1 cm long L The electrode is a long strip with its top and bottom surfaces in contact with copper foil. A stainless steel electrode clip is then clamped onto the copper foil for testing, with a frequency range of 0.01~10. 6 HZ. Based on ionic conductivity σ = T / A * R ( T (Indicates the thickness of the gel). A The cross-sectional area of ​​the polymer gel electrolyte ( A = L * W (The cross-sectional area is the product of the gel's length and width). R The ionic conductivity of the gel can be calculated from the resistance of the polymer gel electrolyte.

[0029] The flexible zinc-air battery assembled from gels prepared in this embodiment of the invention has the following structure: a zinc plate as the anode, and 3.5 mg of carbon black, 3.5 mg of carbon nanotubes, and 3.5 mg of CoN4 material loaded on a 1 cm³ substrate. 2 The carbon cloth serves as the air cathode, with the cathode and anode sandwiched on both sides of the electrolyte to form a sandwich structure. One side of the cathode is covered with a current collector, and the outermost layer of the battery is wrapped with breathable tape.

[0030] The open-circuit voltage and discharge polarization curve of the flexible zinc-air battery prepared in this embodiment of the invention were measured by the Shanghai Chenhua workstation, and the rate and charge-discharge cycle curves were measured by the battery on the Blue Electricity testing system.

[0031] Example 1

[0032] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, and neutralized with 3.75 mL of 10 mol / L sodium hydroxide. The mixture was stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, and then poured into the sodium acrylate solution. The mixture was stirred for 10 min to ensure homogeneity. Finally, 40 mg of the initiator ammonium persulfate was added. After completion, the solution was poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, thus obtaining the hydrogel electrolyte.

[0033] Figure 2 The electrochemical impedance spectroscopy (EIS) measured for the sample prepared in Example 1, and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density measured for the flexible air battery assembled in Example 1, at 1 mA cm⁻¹ -2 The constant current charge-discharge curves are shown in Figure (a). From Figure (a), the ionic conductivity of the gel electrolyte can be calculated to be 270 mS / cm. -1 A zinc-air battery was assembled using this electrolyte. Figure (b) shows the rate capability of the prepared battery. Figure (c) shows the open-circuit voltage of 1.43 V, and Figure (d) shows the power density of the battery of 139 mW / cm². -2 From Figure (e), the cycle life of the battery is 72 h.

[0034] Example 2

[0035] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, neutralized with 3.75 mL of 10 mol / L sodium hydroxide, and stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, then poured into the sodium acrylate solution and stirred for 10 min to mix thoroughly. Next, 6 mg of TpPa was added, and the mixture was stirred for 10 min to disperse thoroughly. Finally, 40 mg of the initiator ammonium persulfate was added. The solution was then poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, yielding the hydrogel electrolyte.

[0036] Figure 1 The diagrams show the structural schematics of the six COF materials used, with Figure (a) showing the structural schematic of TpPa.

[0037] Figure 3 The electrochemical impedance spectroscopy (EIS) measured for the sample prepared in Example 2, and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density measured for the flexible air battery assembled in Example 2, at 1 mA cm⁻¹ -2The constant current charge-discharge curves are shown in Figure (a). From Figure (a), the ionic conductivity of the gel electrolyte can be calculated to be 307 mS / cm. -1 A zinc-air battery was assembled using this electrolyte. Figure (b) shows the rate capability of the prepared battery. Figure (c) shows the open-circuit voltage of 1.44 V, and Figure (d) shows the power density of the battery of 180 mW / cm². -2 As shown in Figure (e), the cycle life of the battery is 76 h.

[0038] Example 3

[0039] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, neutralized with 3.75 mL of 10 mol / L sodium hydroxide, and stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, then poured into the sodium acrylate solution and stirred for 10 min to mix thoroughly. Next, 6 mg of TpPa(SO3H) was added, and the mixture was stirred for 10 min to disperse thoroughly. Finally, 40 mg of the initiator ammonium persulfate was added. The solution was then poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, yielding the hydrogel electrolyte.

[0040] Figure 1 The diagrams show the structures of six COF materials used, with Figure (c) showing the structure of TpPa(SO3H).

[0041] Figure 4 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 3 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled in Example 4 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown in Figure (a). From Figure (a), the ionic conductivity of the gel electrolyte can be calculated to be 346 mS / cm. -1 A zinc-air battery was assembled using this electrolyte. Figure (b) shows the rate capability of the prepared battery. Figure (c) shows the open-circuit voltage of 1.5 V, and Figure (d) shows the power density of the battery of 255 mW / cm³. -2 As shown in Figure (e), the cycle life of the battery is 120 h.

[0042] Example 4

[0043] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, neutralized with 3.75 mL of 10 mol / L sodium hydroxide, and stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, then poured into the sodium acrylate solution, and stirred for 10 min to mix thoroughly. Next, 6 mg of TpPa(COOH) was added, and stirred for 10 min to disperse thoroughly. Finally, 40 mg of the initiator ammonium persulfate was added. After completion, the solution was poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, thus obtaining the hydrogel electrolyte.

[0044] Figure 1 The diagrams show the structural schematics of the six COF materials used, with Figure (e) showing the structural schematic of TpPa(COOH).

[0045] Figure 5 The open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample prepared in Example 4 were measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves were obtained. A zinc-air battery was assembled using this electrolyte. Figure (a) shows an open-circuit voltage of 1.42 V, Figure (b) shows the rate capability of the prepared battery, and Figure (c) shows a power density of 232 mW / cm². -2 As shown in Figure (d), the cycle life of the battery is 51 h.

[0046] Example 5

[0047] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, neutralized with 3.75 mL of 10 mol / L sodium hydroxide, and stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, then poured into the sodium acrylate solution and stirred for 10 min to mix thoroughly. Next, 6 mg of TpBD was added, and the mixture was stirred for 10 min to disperse thoroughly. Finally, 40 mg of the initiator ammonium persulfate was added. The solution was then poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, yielding the hydrogel electrolyte.

[0048] Figure 1 The diagrams show the structures of the six COF materials used, with Figure (b) showing the structure of TpBD.

[0049] Figure 6The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 5 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled in Example 3 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown in Figure (a). From Figure (a), the ionic conductivity of the gel electrolyte can be calculated to be 325 mS / cm. -1 A zinc-air battery was assembled using this electrolyte. Figure (b) shows the rate capability of the prepared battery. Figure (c) shows the open-circuit voltage of 1.45 V, and Figure (d) shows the power density of the battery of 195 mW / cm³. -2 As shown in Figure (e), the cycle life of the battery is 87 h.

[0050] Example 6

[0051] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, neutralized with 3.75 mL of 10 mol / L sodium hydroxide, and stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, then poured into the sodium acrylate solution and stirred for 10 min to mix thoroughly. Next, 6 mg of TpBD(SO3H)2 was added and stirred for 10 min to disperse thoroughly. Finally, 40 mg of the initiator ammonium persulfate was added. After completion, the solution was poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, thus obtaining the hydrogel electrolyte.

[0052] Figure 1 The diagrams show the structures of the six COF materials used, with Figure (d) showing the structure of TpBD(SO3H)2.

[0053] Figure 7 The electrochemical impedance spectroscopy (EIS) of the sample prepared in Example 6 and the open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled in Example 5 are measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown in Figure (a). From Figure (a), the ionic conductivity of the gel electrolyte can be calculated to be 325 mS / cm. -1 A zinc-air battery was assembled using this electrolyte. Figure (b) shows the rate capability of the prepared battery. Figure (c) shows the open-circuit voltage of 1.47 V, and Figure (d) shows the power density of the battery of 220 mW / cm³. -2 As shown in Figure (e), the cycle life of the battery is 95 h.

[0054] Example 7

[0055] First, 60 mg of the crosslinking agent N,N'-methylenebisacrylamide was dissolved in 1.8 mL of acrylic acid, neutralized with 3.75 mL of 10 mol / L sodium hydroxide, and stirred for 10 min to obtain a sodium acrylate solution. 8.6 g of potassium hydroxide and 1.12 g of zinc acetate were dissolved in 20 mL of water, then poured into the sodium acrylate solution and stirred for 10 min to mix thoroughly. Next, 6 mg of TpBD(COOH)₂ was added and stirred for 10 min to disperse thoroughly. Finally, 40 mg of the initiator ammonium persulfate was added. The solution was then poured into a mold and allowed to stand for 10–20 min to allow gel polymerization, yielding the hydrogel electrolyte.

[0056] Figure 1 The diagrams show the structures of six COF materials used, with Figure (f) showing the structure of TpBD(COOH)2.

[0057] Figure 8 The open-circuit voltage, rate capability, discharge polarization curve, and corresponding power density of the flexible air battery assembled from the sample prepared in Example 7 were measured at 1 mA cm⁻¹. -2 The constant current charge-discharge curves are shown. A zinc-air battery was assembled using this electrolyte. Figure (a) shows an open-circuit voltage of 1.44 V, Figure (b) shows the rate capability of the prepared battery, and Figure (c) shows a power density of 248 mW / cm². -2 As shown in Figure (d), the cycle life of the battery is 93 h.

Claims

1. A method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material through in-situ polymerization, characterized in that, Includes the following steps: Zinc salt and potassium hydroxide solution are added to sodium acrylate solution and stirred until evenly dispersed. Then, covalent organic framework material is added and stirred until evenly dispersed. Ammonium persulfate initiator is added, and the mixture is poured into a mold for gel polymerization to obtain in-situ polymerized sodium acrylate hydrogel containing covalent organic framework material. The sodium acrylate solution is obtained by adding sodium hydroxide solution dropwise to an acrylic acid solution containing N,N'-methylenebisacrylamide and continuing to stir to obtain a neutralized sodium acrylate solution. The covalent organic framework material is selected from any one of TpPa(SO3H), TpPa(COOH), TpBD(SO3H)2, and TpBD(COOH)2.

2. The method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material by in-situ polymerization according to claim 1, characterized in that, The concentration of sodium hydroxide is 5-10 mol / L, the concentration of crosslinking agent N,N'-methylenebisacrylamide in the acrylic acid solution is 30-40 mg / mL, and the molar ratio of sodium hydroxide to acrylic acid is 1:1.0-1.

10.

3. The method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material by in-situ polymerization according to claim 1, characterized in that, The zinc salts mentioned include any one of zinc acetate, zinc sulfate, zinc chloride, zinc oxalate, and zinc nitrate.

4. The method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material by in-situ polymerization according to claim 1, characterized in that, The concentration of potassium hydroxide is 5-8 mol / L, and the concentration of zinc salt is 0.1-0.5 mol / L.

5. The method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material by in-situ polymerization according to claim 1, characterized in that, The concentration of the covalent organic framework material was 0.12–0.36 mg / mL.

6. The method for preparing sodium polyacrylate hydrogel containing a covalent organic framework material by in-situ polymerization according to claim 1, characterized in that, The concentration of the initiator ammonium persulfate in the mixed solution is 1~2 mg / mL, and the polymerization time is 10~20 min.

7. A gel electrolyte, characterized in that, This includes preparing an in-situ polymerized sodium polyacrylate hydrogel containing a covalent organic framework material using the method described in any one of claims 1-6.

8. A rechargeable flexible zinc-air battery, characterized in that, Includes the gel electrolyte as described in claim 7.

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