Method for preparing self-healing gel polymer electrolyte through in-situ polymerization

Abstract

The invention relates to a method for preparing a self-healing gel polymer electrolyte through in-situ polymerization. The method comprises the following steps: preparing a self-healing monomer UPyMA from self-healing raw materials including 2-amino-4-hydroxy-6-methylpyrimidine, dimethyl sulfoxide (DMSO) and a double-bond monomer isocyano ethyl methacrylate; the preparation method comprises the following steps: uniformly mixing polyethylene glycol methyl ether acrylate (PEGMEA), polyethylene glycol diacrylate (PEGDA) and a thermal initiator azodiisobutyronitrile (AIBN) to obtain a polymer matrix, and then mixing the polymer matrix with an electrolyte to obtain a precursor solution; fully dissolving a self-healing monomer UPyMA in the precursor solution to obtain a self-healing monomer solution; self-healing monomer solutions are injected into the two sides of the PP diaphragm respectively, and a battery is assembled; a PEGMEA and UPyMA copolymer containing a 3D cross-linked network is constructed through an in-situ thermal polymerization method, so that the self-healing gel polymer electrolyte PEGUPY with relatively low battery interface resistance is prepared. By introducing the self-healing monomer for copolymerization, the interface impedance is successfully reduced, meanwhile, the growth of lithium dendrites is inhibited, and the cycle performance of the battery is improved.

Description

Technical Field

[0001] The invention relates to a method for preparing a gel polymer, in particular to a method for preparing a self-healing gel polymer electrolyte by in-situ polymerization. Background Art

[0002] Lithium-ion batteries are considered the primary energy storage devices for portable and wearable electronic devices due to their high energy density, high operating voltage, low self-discharge effect, and lack of memory effect. However, traditional lithium-ion batteries are mostly rigid structures, and the electrolyte easily separates from the electrode material when bent or folded, leading to internal short circuits and even safety issues in the battery. Gel polymer electrolytes composed of polymers and lithium salts have advantages such as good flexibility, thermal stability, and processability, making them the main choice for safe electrolytes. The preparation of gel electrolytes includes casting, phase separation, electrospinning, and in-situ polymerization. Among them, the in-situ polymerization method is the direct polymerization of the precursor solution into a film in the battery, which has the advantages of low production cost, seamless interface contact, and strong processability, and is more suitable for large-scale production of gel electrolytes.

[0003] In gel polymer electrolytes prepared by in situ polymerization, impurity particles that penetrate the electrode / electrolyte interface can lead to irregular lithium deposition, resulting in damage and cracks at the electrode-electrolyte interface. Once cracks are generated, they will aggravate the growth of lithium dendrites. Although in situ polymerization can ensure good interfacial contact, changes in the electrode volume will occur during the battery cycle, resulting in a decrease in interfacial contact and an increase in battery impedance. Self-healing refers to the ability to spontaneously recover from mechanical damage and is an important survival characteristic in nature. Endowing gel polymers with self-healing properties helps to extend the service life of the polymer and repair microcracks, which can effectively inhibit the formation of lithium dendrites. Therefore, the preparation of flexible, electrochemically superior self-healing gel polymer electrolytes by in situ polymerization is of great significance in inhibiting lithium dendrites and improving battery safety.

[0004] Purpose of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a self-healing gel polymer electrolyte by in-situ polymerization. The prepared self-healing gel polymer electrolyte effectively reduces the interfacial impedance, inhibits dendrite growth and improves battery cycle stability.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] 1) 2-2.5 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine was added to 60-100 mL of dimethyl sulfoxide (DMSO) and heated with stirring to fully dissolve it. 2.64-3.0 g of the double bond monomer isocyanoethyl methacrylate was then added and naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration and washing, the white solid was vacuum dried to obtain the self-healing monomer UPyMA;

[0008] 2) washing the self-healing monomer UPyMA synthesized in step 1) and drying it in a vacuum oven to obtain the self-healing monomer UPyMA from which the solvent has been removed;

[0009] 3) 1-1.3 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 μL of 1% polyethylene glycol diacrylate (PEGDA), and 1-2 mg of a 0.05% thermal initiator azobisisobutyronitrile (AIBN) were mixed to obtain a polymer matrix, and then the polymer matrix was dissolved in an electrolyte at a mass ratio of 1:1 under stirring to obtain a precursor solution, wherein the electrolyte used was 1 MOL / L LIPF6EC:DEC (1:1 v / v%);

[0010] 4) fully dissolving the self-healing monomer UPyMA from which the solvent has been removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 1% to 10%;

[0011] 5) Inject 35-50 μl of the self-healing monomer solution from step 4) onto both sides of a 19 mm diameter PP separator to assemble a battery;

[0012] 6) A PEGMEA and UPyMA copolymer containing a 3D cross-linked network was constructed by in situ thermal polymerization to prepare a self-healing gel polymer electrolyte PEGUPY with low interface resistance with the battery.

[0013] The heating and stirring in step 1) is carried out at 150° C. for 10 minutes.

[0014] The cleaning in step 1) is performed by using acetone and methanol three times each.

[0015] The vacuum drying in step 1) is performed at 30° C. for 5 h.

[0016] The cleaning in step 2) is performed by washing with acetone and methanol three times respectively and then drying in a vacuum oven at 30° C. for 4 hours.

[0017] The stirring in step 3) is carried out at a speed of 300 r / min for 1 hour.

[0018] The PP membrane in step 5) is Celgard 2500 membrane.

[0019] After the battery is assembled in step 5), the battery is allowed to stand to allow the self-healing monomer solution to fully penetrate the battery.

[0020] The in-situ thermal polymerization method of step 6) is to place the assembled battery in a 70° C. oven for 6 hours to allow the monomers to fully copolymerize, thereby completing the in-situ preparation of PEGUPY.

[0021] In response to the poor interface contact caused by the growth of lithium dendrites at room temperature and the repeated changes in electrode volume during the cycle of traditional gel polymer electrolytes, the present invention successfully reduces the interfacial impedance by introducing self-healing monomer copolymerization, while inhibiting the growth of lithium dendrites and improving the cycle performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the electrochemical impedance spectrum of the stainless steel-stainless steel button cell assembled from the precursor solutions of Examples 1-3 of the present invention and Comparative Example 1 at 0.1-105 Hz.

[0023] Figure 2 This is a time-voltage curve of a lithium-lithium symmetrical battery assembled from the precursor solutions of Example 1 of the present invention and Comparative Example 1 at 0.1 mA cm-2.

[0024] Figure 3 1 is a time-voltage curve of a lithium-lithium iron phosphate full battery assembled from the precursor solutions of Example 1 of the present invention and Comparative Example 1 at 0.2C.

[0025] Figure 4 It is the first cycle discharge specific capacity-voltage curve of the lithium-lithium iron phosphate full battery assembled by the precursor solutions of Example 1 of the present invention and Comparative Example 1 at 0.2C. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Example 1:

[0028] 1) 2 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine was added to 80 mL of dimethyl sulfoxide (DMSO) and stirred at 150°C for 10 min to fully dissolve it. Then, 2.64 g of the double bond monomer isocyanoethyl methacrylate was added and naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration, it was washed three times with acetone and methanol respectively, and dried in vacuum at 30°C for 5 h to obtain the self-healing monomer UPyMA;

[0029] 2) washing the self-healing monomer UPyMA synthesized in step 1) with acetone and methanol three times respectively, and then drying in a vacuum oven at 30° C. for 4 h to obtain the self-healing monomer UPyMA from which the solvent has been removed;

[0030] 3) 1 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 μL of 1% polyethylene glycol diacrylate (PEGDA), and 1.5 mg of a 0.05% thermal initiator azobisisobutyronitrile (AIBN) were mixed to obtain a polymer matrix. The polymer matrix was then dissolved in an electrolyte at a mass ratio of 1:1 by stirring at 300 rpm for 1 hour to obtain a precursor solution. The electrolyte used was 1 MOL / LLIPF6 EC:DEC (1:1 v / v%).

[0031] 4) fully dissolving the self-healing monomer UPyMA from which the solvent was removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 3%;

[0032] 5) Inject 40 μl of the self-healing monomer solution from step 4) onto both sides of a 19 mm diameter Celgard 2500 separator, assemble the battery, and allow it to stand to allow the self-healing monomer solution to fully penetrate the separator.

[0033] 6) The assembled battery was placed in an oven at 70°C for 6 h by in situ thermal polymerization to construct a PEGMEA and UPyMA copolymer containing a 3D cross-linked network, thereby preparing a self-healing gel polymer electrolyte PEGUPY (abbreviated as PEGUPY-3) with low interface resistance with the battery.

[0034] Example 2:

[0035] 1) 2.3 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine was added to 60 mL of dimethyl sulfoxide (DMSO) and stirred at 150°C for 10 min to fully dissolve it. Then, 2.8 g of the double bond monomer isocyanoethyl methacrylate was added and naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration, it was washed three times with acetone and methanol respectively, and dried in vacuum at 30°C for 5 h to obtain the self-healing monomer UPyMA;

[0036] 2) washing the self-healing monomer UPyMA synthesized in step 1) with acetone and methanol three times respectively, and then drying in a vacuum oven at 30° C. for 4 h to obtain the self-healing monomer UPyMA from which the solvent has been removed;

[0037] 3) 1.2 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 μL of 1% polyethylene glycol diacrylate (PEGDA), and 1.2 mg of a 0.05% thermal initiator azobisisobutyronitrile (AIBN) were mixed to obtain a polymer matrix. The polymer matrix was then dissolved in an electrolyte at a mass ratio of 1:1 by stirring at 300 rpm for 1 hour to obtain a precursor solution. The electrolyte used was 1 MOL / LLIPF6 EC:DEC (1:1 v / v%).

[0038] 4) fully dissolving the self-healing monomer UPyMA from which the solvent has been removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 5%;

[0039] 5) Inject 35 μl of the self-healing monomer solution from step 4) onto both sides of a 19 mm diameter Celgard 2500 separator, assemble the battery, and allow it to stand to allow the self-healing monomer solution to fully penetrate the separator.

[0040] 6) The assembled battery was placed in an oven at 70°C for 6 h by in situ thermal polymerization to construct a PEGMEA and UPyMA copolymer containing a 3D cross-linked network, thereby preparing a self-healing gel polymer electrolyte PEGUPY (abbreviated as PEGUPY-5) with low interface resistance with the battery.

[0041] Example 3:

[0042] 1) 2.5 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine was added to 100 mL of dimethyl sulfoxide (DMSO) and stirred at 150°C for 10 min to fully dissolve it. Then, 2.7 g of the double bond monomer isocyanoethyl methacrylate was added and naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration, the solid was washed three times with acetone and methanol respectively, and dried in vacuum at 30°C for 5 h to obtain the self-healing monomer UPyMA.

[0043] 2) washing the self-healing monomer UPyMA synthesized in step 1) with acetone and methanol three times respectively, and then drying in a vacuum oven at 30° C. for 4 h to obtain the self-healing monomer UPyMA from which the solvent has been removed;

[0044] 3) 1.3 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 μL of 1% polyethylene glycol diacrylate (PEGDA), and 2 mg of a 0.05% thermal initiator azobisisobutyronitrile (AIBN) were mixed to obtain a polymer matrix. The polymer matrix was then dissolved in an electrolyte at a mass ratio of 1:1 by stirring at 300 rpm for 1 hour to obtain a precursor solution. The electrolyte used was 1 MOL / LLIPF6 EC:DEC (1:1 v / v%).

[0045] 4) fully dissolving the self-healing monomer UPyMA from which the solvent was removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 7%;

[0046] 5) Inject 50 μl of the self-healing monomer solution from step 4) onto both sides of a 19 mm diameter Celgard 2500 separator, assemble the battery, and allow it to stand to allow the self-healing monomer solution to fully penetrate the separator.

[0047] 6) The assembled battery was placed in an oven at 70°C for 6 h by in situ thermal polymerization to construct a PEGMEA and UPyMA copolymer containing a 3D cross-linked network, thereby preparing a self-healing gel polymer electrolyte PEGUPY (abbreviated as PEGUPY-7) with low interface resistance with the battery.

[0048] Example 4:

[0049] 1) 2.1 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine was added to 70 mL of dimethyl sulfoxide (DMSO) and stirred at 150°C for 10 min to fully dissolve it. Then, 3 g of the double bond monomer isocyanoethyl methacrylate was added and naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration, it was washed three times with acetone and methanol respectively, and dried in vacuum at 30°C for 5 h to obtain the self-healing monomer UPyMA;

[0050] 2) washing the self-healing monomer UPyMA synthesized in step 1) with acetone and methanol three times respectively, and then drying in a vacuum oven at 30° C. for 4 h to obtain the self-healing monomer UPyMA from which the solvent has been removed;

[0051] 3) 1.1 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 μL of 1% polyethylene glycol diacrylate (PEGDA), and 1.3 mg of azobisisobutyronitrile (AIBN) at a 0.05% concentration as a thermal initiator were mixed to obtain a polymer matrix. The polymer matrix was then dissolved in an electrolyte at a mass ratio of 1:1 by stirring at 300 rpm for 1 hour to obtain a precursor solution, wherein the electrolyte used was 1 MOL / LLIPF6 EC:DEC (1:1 v / v%).

[0052] 4) fully dissolving the self-healing monomer UPyMA from which the solvent has been removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 1%;

[0053] 5) Inject 45 μl of the self-healing monomer solution from step 4) onto both sides of a 19 mm diameter Celgard 2500 separator, assemble the battery, and allow it to stand to allow the self-healing monomer solution to fully penetrate the separator.

[0054] 6) The assembled battery was placed in an oven at 70°C for 6 h by in situ thermal polymerization to construct a PEGMEA and UPyMA copolymer containing a 3D cross-linked network, thereby preparing a self-healing gel polymer electrolyte PEGUPY (abbreviated as PEGUPY-1) with low interface resistance with the battery.

[0055] Example 5:

[0056] 1) 2.3 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine was added to 90 mL of dimethyl sulfoxide (DMSO) and stirred at 150°C for 10 min to fully dissolve it. Then, 2.9 g of the double bond monomer isocyanoethyl methacrylate was added and naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration, it was washed three times with acetone and methanol respectively, and dried in vacuum at 30°C for 5 h to obtain the self-healing monomer UPyMA;

[0057] 2) washing the self-healing monomer UPyMA synthesized in step 1) with acetone and methanol three times respectively, and then drying in a vacuum oven at 30° C. for 4 h to obtain the self-healing monomer UPyMA from which the solvent has been removed;

[0058] 3) 1.2 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 μL of 1% polyethylene glycol diacrylate (PEGDA), and 1.8 mg of a 0.05% thermal initiator azobisisobutyronitrile (AIBN) were mixed to obtain a polymer matrix. The polymer matrix was then dissolved in an electrolyte at a mass ratio of 1:1 by stirring at 300 rpm for 1 hour to obtain a precursor solution, wherein the electrolyte used was 1 MOL / LLIPF6 EC:DEC (1:1 v / v%).

[0059] 4) fully dissolving the self-healing monomer UPyMA from which the solvent was removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 10%;

[0060] 5) Inject 42 μl of the self-healing monomer solution from step 4) onto both sides of a 19 mm diameter Celgard 2500 separator, assemble the battery, and allow it to stand to allow the self-healing monomer solution to fully penetrate the separator.

[0061] 6) The assembled battery was placed in an oven at 70°C for 6 h by in situ thermal polymerization to construct a PEGMEA and UPyMA copolymer containing a 3D cross-linked network, thereby preparing a self-healing gel polymer electrolyte PEGUPY (abbreviated as PEGUPY-10) with low interface resistance with the battery.

[0062] Comparative Example 1: 1 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 microliters of 1% volume fraction of polyethylene glycol diacrylate (PEGDA) and 1.5 mg of 0.05% mass concentration of thermal initiator azobisisobutyronitrile (AIBN) were dissolved in the electrolyte (1M LiPF6 dissolved in EC / DEC, v / v 1:1), wherein the mass ratio of the polymer matrix and the electrolyte was set to 1:1, and stirred at a speed of 300 r / min for 1 hour to obtain a precursor solution. When assembling the battery, the precursor solution was injected into the battery assembled with a polypropylene (PP) separator, and then the battery was placed in a 70°C oven for 6 hours to allow the monomers to fully copolymerize, thereby completing the in situ preparation of PEGUPY (referred to as PEGMEA).

[0063] Application Example 1:

[0064] Assembling the stainless steel-stainless steel button cell battery:

[0065] Stainless steel was used as the positive and negative electrodes, polypropylene was used as the separator, the precursor solution configured in the above Examples 1-3 and Comparative Example 1 was added, and a 2025-type battery shell was used. The stainless steel-stainless steel button battery was assembled in the order of negative electrode shell, stainless steel sheet, precursor solution, separator, precursor solution, stainless steel sheet, gasket, spring sheet, and positive electrode shell.

[0066] The electrochemical impedance spectroscopy test of the zinc-zinc symmetrical button cells assembled in each embodiment and comparative example was performed on an electrochemical workstation in a frequency range of 0.1 Hz to 10 5 Hz. The test was carried out on Chenhua CHI660E, and the test temperature was maintained at 30℃.

[0067] Figure 1 The stainless steel-stainless steel battery assembled with the precursor solutions in Examples 1-3 and Comparative Example 1 was tested at 0.1 Hz-10 5 Electrochemical impedance spectroscopy at Hz frequency.

[0068] As can be seen from the figure, without the use of self-healing monomer copolymerization, the bulk impedance of the gel polymer electrolyte is 14.16Ω. However, when using different amounts of UPyMA monomer copolymerization, the bulk impedance of the gel polymer electrolyte decreases, and when the UPyMA monomer is used in an appropriate amount (Example 1), the bulk impedance can be reduced to 7Ω.

[0069] This indicates that the introduction of an appropriate amount of UPyMA monomer significantly reduces the bulk impedance of the gel electrolyte.

[0070] Application Example 2:

[0071] Assembling Li-Li button cells:

[0072] A lithium sheet with a thickness of 0.4 mm was used as the positive and negative electrodes, polypropylene was used as the separator, the precursor solution configured in the above Example 1 and Comparative Example 1 was added, and a 2025-type battery shell was used. The lithium-lithium symmetrical button battery was assembled in the order of negative electrode shell, lithium sheet, precursor solution, separator, precursor solution, lithium sheet, gasket, spring sheet, and positive electrode shell.

[0073] experiment:

[0074] The lithium-lithium symmetrical button cells assembled in Example 1 and the comparative example were subjected to electrochemical tests. -2 Constant current charge and discharge tests were performed at a current density of 100 nm. The test was performed on a Xinwei battery testing system and the test temperature was maintained at 30°C.

[0075] Cyclic overpotential:

[0076] Figure 2 The symmetrical battery assembled with the precursor solutions in Example 1 and Comparative Example 1 was tested at 0.1 mA cm -2 The current density and 0.1 mAh cm -2 Time-voltage curve under the capacity.

[0077] As shown in the figure, without UPyMA monomers, the overpotential of the lithium-lithium symmetric battery reached 154mV after 300h of cycling. However, when using UPyMA monomers at a mass concentration of 3%, the overpotential of the symmetric battery remained stable at around 67mV. This indicates that the introduction of an appropriate amount of UPyMA monomers significantly reduced the overpotential of the symmetric battery.

[0078] Use Example 3:

[0079] Assembling a lithium-ion iron phosphate full battery:

[0080] Lithium iron phosphate was used as the positive electrode active material, a lithium sheet was used as the negative electrode, polypropylene was used as the separator, the electrolyte configured in Example 1 and Comparative Example 1 was added, and a 2025-type battery shell was used. The lithium-lithium iron phosphate button battery was assembled in the order of negative electrode shell, lithium sheet, precursor solution, separator, precursor solution, positive electrode active material, gasket, spring sheet, and positive electrode shell.

[0081] experiment:

[0082] Electrochemical tests were performed on the full batteries assembled in Example 1 and Comparative Example 1. The tests were conducted on a Newway battery testing system with a battery voltage range of 2.5 to 4.0 V and a test temperature of 30°C.

[0083] Cycle life

[0084] from Figure 3 and Figure 4It can be seen that under the current density of 0.2C, the in-situ polymerized gel polymer battery containing the precursor solution of Example 1 can be stably cycled for 200 cycles, and the battery's first cycle discharge capacity is 143.7 mAh g -1 , its capacity remained at 72.44%. In contrast, the capacity of the battery assembled from the precursor solution of Comparative Example 1 rapidly decayed, with only 79% of the capacity remaining after 80 cycles. This indicates that the introduction of the self-healing monomer UPyMA can effectively improve the cycling stability of the battery, demonstrating its successful application as a comonomer in gel polymer electrolytes.

[0085] This invention addresses the interfacial safety issues associated with in-situ polymerized gel electrolytes, producing an electrolyte system with high safety, excellent electrochemical performance, and superior interfacial properties. This effectively addresses the low ionic conductivity, severe polarization during charge and discharge, and poor cycling stability of currently developed PEGMEA-based gel polymer electrolytes at room temperature. Compared to traditional in-situ polymerized gel polymer electrolytes, the self-healing gel polymer electrolyte of this invention effectively reduces interfacial impedance, inhibits dendrite growth, and improves battery cycling stability, providing a solution for improving the next generation of gel electrolyte systems for flexible electronic devices.

Claims

1. A method for preparing a self-healing gel polymer electrolyte by in-situ polymerization, characterized in that The following steps are involved: 1) 2-2.5 g of the self-healing raw material 2-amino-4-hydroxy-6-methylpyrimidine is added to 60-100 mL of dimethyl sulfoxide (DMSO) and heated and stirred to fully dissolve it, and then 2.64-3.0 g of the double bond monomer isocyanoethyl methacrylate is added, and the mixture is naturally cooled to room temperature to precipitate a large amount of white solid. After vacuum filtration and washing, the white solid is vacuum dried to obtain the self-healing monomer UPyMA; 2) washing the self-healing monomer UPyMA synthesized in step 1) and drying it in a vacuum oven to obtain the self-healing monomer UPyMA from which the solvent has been removed; 3) 1-1.3 mL of polyethylene glycol methyl ether acrylate (PEGMEA), 20 microliters of 1% polyethylene glycol diacrylate (PEGDA) and 1-2 mg of 0.05% thermal initiator azobisisobutyronitrile (AIBN) are mixed to obtain a polymer matrix, and then the polymer matrix is ​​dissolved in an electrolyte at a mass ratio of 1:1 under stirring to obtain a precursor solution, wherein the electrolyte uses 1 MOL / L LIPF6EC:DEC (1:1 V / V%); 4) fully dissolving the self-healing monomer UPyMA from which the solvent is removed in step 2) in the precursor solution to obtain a self-healing monomer solution with a mass concentration of 1% to 10%; 5) Inject 35-50 μl of the self-healing monomer solution of step 4) on both sides of a PP separator with a diameter of 19 mm to assemble a battery; 6) A PEGMEA and UPyMA copolymer containing a 3D cross-linked network was constructed by in situ thermal polymerization to prepare a self-healing gel polymer electrolyte PEGUPY with low interface resistance with the battery.

2. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The heating and stirring in step 1) is stirring at 150° C. for 10 min.

3. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The cleaning in step 1) is performed by using acetone and methanol for three times respectively.

4. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The vacuum drying in step 1) is performed at 30° C. for 5 h.

5. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The cleaning in step 2) is performed by washing with acetone and methanol three times respectively and then drying in a vacuum oven at 30° C. for 4 hours.

6. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The stirring in step 3) is carried out at a speed of 300 r / min for 1 hour.

7. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The PP diaphragm in step 5) is Celgard 2500 diaphragm.

8. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: After the battery is assembled in step 5), the battery is allowed to stand to allow the self-healing monomer solution to fully infiltrate the battery.

9. The method for preparing a self-healing gel polymer electrolyte by in-situ polymerization according to claim 1, characterized in that: The in-situ thermal polymerization method of step 6) is to place the assembled battery in a 70° C. oven for 6 hours to allow the monomers to fully copolymerize, thereby completing the in-situ preparation of PEGUPY.

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