Preparation method of dendrite-free gel electrolyte and application thereof

Abstract

The application discloses a preparation method of dendrite-free gel electrolyte and application thereof, and comprises the following steps: synthesizing a porphyrin-based covalent organic framework (PPCOF); preparing a gel precursor solution; and preparing an in-situ polymerized PMMA-based gel electrolyte. The electrolyte has the characteristics of simple preparation method, cheap and easily available raw materials, good electrode interface contact (in-situ polymerization), and the like, and can solve the problems of poor PMMA-based GPE electrode contact, low lithium ion transference number and easy growth of lithium dendrites, thereby providing guidance for the development of dendrite-free solid-state lithium metal batteries.

Description

Technical Field

[0001] This invention belongs to the field of solid electrolyte preparation technology, specifically relating to a method for preparing dendrite-free gel electrolyte and its application. Background Technology

[0002] Traditional lithium-ion batteries face challenges related to safety and energy density due to the susceptibility of liquid electrolytes to leakage and explosion. Solid-state lithium batteries, with their cathodes and anodes physically isolated by a solid electrolyte, offer significantly improved safety and are therefore a promising future technology for lithium batteries. Polymer electrolytes have been extensively studied in recent years due to their excellent properties, including good safety and stability, as well as high mechanical flexibility. To achieve excellent battery performance, polymer electrolytes are required to possess high ionic conductivity, lithium-ion transference number, mechanical strength, and good electrochemical and thermodynamic stability. Polymer electrolytes can be divided into two categories: dry polymer electrolytes (DPEs), which have low room-temperature ionic conductivity (10⁻⁶ Ω·cm). -4 ~10 -5 The S / cm ratio is still difficult to use in batteries; another type is gel polymer electrolyte (GPE), which is a polymer network with a suitable microstructure formed by polymer, plasticizer and lithium salt through a certain method, and uses liquid electrolyte molecules fixed in the microstructure to achieve ion conduction.

[0003] While PMMA-based GPE has advantages, its low lithium-ion transference number (generally not exceeding 0.5) and difficulty in achieving sufficient contact with the electrode limit its further applications. An ideal electrolyte system should have a lithium-ion transference number close to 1, and the electrolyte itself should possess a high lithium-ion transference number to reduce concentration polarization during charge and discharge, decrease potential loss in the battery, promote uniform lithium transport, slow lithium dendrite growth, and thus effectively improve the long-cycle stability of solid-state lithium batteries. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments.

[0005] As one aspect of the present invention, the present invention provides a method for preparing a dendrite-free gel electrolyte, comprising,

[0006] (1) Dissolve 468.6 mg of terephthalaldehyde in 150 mL of propionic acid solvent and stir for 30 min; add 484.8 μL of pyrrole, 100 μL of trifluoroacetic acid, and 1 mL of nitrobenzene and stir at room temperature for 30 min.

[0007] (2) Heat the resulting mixture to 130°C and react continuously for 12 hours. After filtration, wash the mixture three times with deionized water and ethanol, and then filter to obtain filter cake.

[0008] (3) After vacuum drying at 60℃ for 12h, porphyrin-based covalent organic framework (PPCOF) was obtained.

[0009] (4) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents in a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA, crosslinking agent) in a molar ratio of 5:1, and mix and stir for 5 h;

[0010] (5) Add 0.005 g PPCOF to the above mixed solution and stir for 5 h; weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution, stir for 20 min to obtain the precursor solution;

[0011] (6) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0012] (7) Place in a 60℃ oven and heat for 12 hours to complete in-situ polymerization, obtaining dendrite-free gel electrolyte (E1M5F). 0.5 ).

[0013] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (1), the molar ratio of terephthalaldehyde to pyrrole is 1:2.

[0014] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (1), trifluoroacetic acid is used as an acid catalyst and nitrobenzene is used as an oxidant.

[0015] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (2), the reaction temperature is 130°C and the reaction time is 12h.

[0016] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (3), the drying includes drying the sample at 60°C.

[0017] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (4), ETPTA is used as a crosslinking agent and the molar ratio with MMA is 1:5.

[0018] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (5), the weight percentage of PPCOF is 0.5 wt%.

[0019] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (6), 30 μL of precursor mixed solution is added to each side of the PP membrane.

[0020] As a preferred embodiment of the preparation method of the dendrite-free gel electrolyte of the present invention: in step (7), the in-situ thermal polymerization temperature is 60°C and the polymerization time is 12h.

[0021] The beneficial effects of this invention are as follows: This invention provides a method for preparing a dendrite-free gel electrolyte. First, a porphyrin-based covalent organic framework (PPCOF) is synthesized as the electrolyte filler. Experimental results show that PPCOF provides a rapid and continuous ion channel in the prepared electrolyte, accelerating lithium-ion transport and improving ionic conductivity. Simultaneously, PPCOF can effectively immobilize anions, thereby increasing the lithium-ion transference number of the gel electrolyte, regulating lithium-ion transport, and uniformly distributing lithium flux, thus effectively slowing down lithium dendrite growth and improving the lifespan of solid-state lithium batteries. This gel electrolyte exhibits a high conductivity of 1.01 mS / cm and an electrochemical window of >5V at room temperature. The assembled Li / / Li battery can cycle stably for nearly 10,000 hours at a current of 0.5 mA, demonstrating excellent lithium stability and a wide temperature range. Furthermore, the assembled Li / / LFP full cell also exhibits good rate capability and long cycle performance. This electrolyte has the advantages of simple preparation method, cheap and readily available raw materials, and good contact with the electrode interface (in-situ polymerization). It is expected to solve problems such as poor contact of PMMA-based GPE electrodes, low lithium-ion transference number and easy growth of lithium dendrites, and provide some ideas for the development of solid-state lithium metal batteries. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0023] Figure 1 Preparation of PPCOF.

[0024] Figure 2 The optimal ratio of MMA and ETPTA was determined.

[0025] Figure 3 The optimal ratio of PPCOF packing material was determined.

[0026] Figure 4 This is the SEM image of Example 1.

[0027] Figure 5XRD images of E1M5 and Example 1.

[0028] Figure 6 For LE, E1M5, E1M5F 0.5 LSV comparison.

[0029] Figure 7 For LE, E1M5, E1M5F 0.5 Comparison of lithium-ion transference numbers.

[0030] Figure 8 For LE, E1M5, E1M5F 0.5 Comparison of ion migration barriers.

[0031] Figure 9 For LE, E1M5, E1M5F 0.5 Comparison of depositional morphology on Cu.

[0032] Figure 10 For LE, E1M5, E1M5F 0.5 Comparison of COMSOL simulations of sedimentary morphology.

[0033] Figure 11 For LE, E1M5, E1M5F 0.5 Comparison of SEI layer morphology.

[0034] Figure 12 For the assembly of Li / E1M5F 0.5 Long-cycle performance of Li batteries.

[0035] Figure 13 For the assembly of LFP / E1M5F 0.5 The rate capability and long-cycle performance of / Li batteries. Detailed Implementation

[0036] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0037] Example 1:

[0038] (1) Dissolve 468.6 mg of terephthalaldehyde in 150 mL of propionic acid solvent and stir for 30 min; add 484.8 μL of pyrrole, 100 μL of trifluoroacetic acid and 1 mL of nitrobenzene and stir at room temperature for 30 min to obtain a mixture;

[0039] (2) Heat the mixture obtained in step (1) to 130°C and react continuously for 12 hours. After filtration, wash the mixture three times with deionized water and ethanol, and then filter to obtain filter cake.

[0040] (3) The product of step (2) was dried under vacuum at 60°C for 12 h to obtain porphyrin-based covalent organic framework (PPCOF).

[0041] (4) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents and a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA, crosslinking agent) in a molar ratio of 5:1, and mix and stir for 5 h to obtain a mixed solution;

[0042] (5) Add 0.005 g PPCOF to the mixed solution obtained in step (4) and stir for 5 h; weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution, stir for 20 min to obtain the precursor solution;

[0043] (6) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0044] (7) Place in a 60℃ oven and heat for 12 hours to complete in-situ polymerization, obtaining dendrite-free gel electrolyte (E1M5F). 0.5 ).

[0045] Compare with Example 1:

[0046] (1) Dissolve 468.6 mg of terephthalaldehyde in 150 mL of propionic acid solvent and stir for 30 min; add 484.8 μL of pyrrole, 100 μL of trifluoroacetic acid, and 1 mL of nitrobenzene and stir at room temperature for 30 min.

[0047] (2) Heat the resulting mixture to 130°C and react continuously for 12 hours. After filtration, wash the mixture three times with deionized water and ethanol, and then filter to obtain filter cake.

[0048] (3) After vacuum drying at 60℃ for 12h, porphyrin-based covalent organic framework (PPCOF) was obtained.

[0049] (4) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents in a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and pentaerythritol tetraacrylate (PETEA, crosslinking agent) in a molar ratio of 5:1, and mix and stir for 5 h.

[0050] (5) Add 0.005 g PPCOF to the above mixed solution and stir for 5 h; weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution, stir for 20 min to obtain the precursor solution;

[0051] (6) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0052] (7) Heat in a 60℃ oven for 12 hours to complete in-situ polymerization and obtain gel electrolyte (P1M5F). 0.5 ).

[0053] Subsequently, in the electrochemical performance tests, including impedance, lithium-ion conductivity, electrochemical window testing, lithium symmetry, and LFP half-cell performance tests, P1M5F... 0.5 The ionic conductivity was 0.42 mS / cm, the electrochemical window was ~4.6 V, and the assembled Li / / Li battery only cycled for 300 h at a current of 0.5 mA, with performance significantly lower than that of E1M5F in Example 1. 0.5 performance.

[0054] Compare with Example 2:

[0055] The effect of different amounts of ETPTA crosslinking agent on electrochemical performance.

[0056] (1) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents and a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA, crosslinking agent) in a molar ratio of 1:1, 5:1 or 10:1 respectively, and mix and stir for 5 h;

[0057] (2) Weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution. Stir for 20 min to obtain the precursor solution.

[0058] (3) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0059] (4) Heat in a 60℃ oven for 12 hours to complete in-situ polymerization and obtain gel electrolytes (E1M1, E1M5 and E1M). 10 ).

[0060] Subsequently, some basic electrochemical performance tests were conducted, and the results are as follows: Figure 2 As shown, E1M1, E1M5 and E1M 10 The ionic conductivities of E1M1 and E1M are 0.457 mS / cm, 0.581 mS / cm, and 0.472 mS / cm, respectively. 10The ionic conductivity of both MMA and ETPTA is lower than that of E1M5, and LSV testing also revealed that their electrochemical windows are not as wide as those of E1M5. Therefore, the molar ratio of MMA to ETPTA was determined to be 5:1.

[0061] Compare with Example 3:

[0062] (1) Dissolve 468.6 mg of terephthalaldehyde in 150 mL of propionic acid solvent and stir for 30 min; add 484.8 μL of pyrrole, 100 μL of trifluoroacetic acid, and 1 mL of nitrobenzene and stir at room temperature for 30 min.

[0063] (2) Heat the resulting mixture to 130°C and react continuously for 12 hours. After filtration, wash the mixture three times with deionized water and ethanol, and then filter to obtain filter cake.

[0064] (3) After vacuum drying at 60℃ for 12h, porphyrin-based covalent organic framework (PPCOF) was obtained.

[0065] (4) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents in a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA, crosslinking agent) in a molar ratio of 5:1, and mix and stir for 5 h;

[0066] (5) Add 0.002 g and 0.01 g PPCOF to the above mixed solution and stir for 5 h; weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution, stir for 20 min to obtain the precursor solution;

[0067] (6) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0068] (7) Place in a 60℃ oven and heat for 12 hours to complete in-situ polymerization, obtaining gel electrolyte (E1M5F). 0.2 (and E1M5F1).

[0069] Electrochemical performance tests were then conducted, and the results are as follows: Figure 3 As shown, E1M5F 0.2 The ionic conductivities of E1M5F1 and E1M5F1 are 0.732 mS / cm and 0.815 mS / cm, respectively. 0.2 The ionic conductivity of both PPCOF and E1M5F1 is lower than that of Example 1, and LSV testing also revealed that their electrochemical windows are not as wide as those of Example 1. Therefore, the optimal addition amount of PPCOF was determined to be 0.5 wt%.

[0070] Compare with Example 4:

[0071] (1) Dissolve 468.6 mg of terephthalaldehyde in 150 mL of propionic acid solvent and stir for 30 min; add 484.8 μL of pyrrole, 100 μL of trifluoroacetic acid, and 1 mL of nitrobenzene and stir at room temperature for 30 min.

[0072] (2) Heat the resulting mixture to 130°C and react continuously for 12 hours. After filtration, wash the mixture three times with deionized water and ethanol, and then filter to obtain filter cake.

[0073] (3) After vacuum drying at 60℃ for 12h, porphyrin-based covalent organic framework (PPCOF) was obtained.

[0074] (4) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents in a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA, crosslinking agent) in a molar ratio of 5:1, and mix and stir for 5 h;

[0075] (5) Add 0.005 g PPCOF to the above mixed solution and stir for 5 h; weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution, stir for 20 min to obtain the precursor solution;

[0076] (6) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0077] (7) Place in a 60℃ oven and heat for 12 hours to complete in-situ polymerization, and obtain gel electrolytes (E1M5 and E1M5F). 0.5 ).

[0078] (8) The preparation process of E1M5 is the same as the above steps except that PPCOF is not added.

[0079] Electrochemical performance testing was conducted. Figure 6 Note that the electrochemical windows of LE and E1M5 are ~4.3V and ~4.9V, respectively, and the electrochemical windows of both LE and E1M5 are smaller than those of Example 1 (>5V); Figure 7 It is noted that the lithium-ion transference numbers of LE and E1M5 are 0.41 and 0.49V, respectively, and the lithium-ion transference numbers of both LE and E1M5 are less than those of Example 1 (0.87). Figure 8The ion migration barriers of LE and E1M5 are 0.045 eV and 0.063 eV, respectively, both greater than those in Example 1 (0.042 eV). Therefore, the introduction of PPCOF effectively improves the electrochemical performance of the gel electrolyte. Its Li / / LFP full cell also exhibits good rate capability and long cycling performance, such as... Figure 13 As shown.

[0080] Compare with Example 5:

[0081] (1) Dissolve 468.6 mg of terephthalaldehyde in 150 mL of propionic acid solvent and stir for 30 min; add 484.8 μL of pyrrole, 100 μL of trifluoroacetic acid, and 1 mL of nitrobenzene and stir at room temperature for 30 min.

[0082] (2) Heat the resulting mixture to 130°C and react continuously for 12 hours. After filtration, wash the mixture three times with deionized water and ethanol, and then filter to obtain filter cake.

[0083] (3) After vacuum drying at 60℃ for 12h, porphyrin-based covalent organic framework (PPCOF) was obtained.

[0084] (4) Measure 1 mL of 1 M LiDFOB electrolyte, with EC and DMC as solvents in a volume ratio of 1:1 (LE); add 0.1 g of methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA, crosslinking agent) in a molar ratio of 5:1, and mix and stir for 5 h;

[0085] (5) Add 0.005 g PPCOF to the above mixed solution and stir for 5 h; weigh 1 wt% azobisisobutyronitrile (AIBN, initiator) and add it to the above mixed solution, stir for 20 min to obtain the precursor solution;

[0086] (6) Add 30uL of the above precursor mixture solution to each side of the PP membrane and assemble Li / / Li and Li / / LFP batteries (CR2032);

[0087] (7) Place in a 60℃ oven and heat for 12 hours to complete in-situ polymerization, and obtain gel electrolytes (E1M5 and E1M5F). 0.5 ).

[0088] (8) The preparation process of E1M5 is the same as the above steps except that PPCOF is not added.

[0089] The lithium deposition morphology was investigated by assembling Li / / Cu cells, and the results are as follows: Figure 9 As shown. For a current density of 0.5 mA / cm²... -2The Li|Cu battery, after 50 cycles, was disassembled and subjected to SEM testing. The results showed that, compared to LE ( Figure 9 a) E1M5 has a certain positive effect on the regulation of lithium deposition, but the presence of grains is still clearly visible. Figure 9 b), and after adding PPCOF ( Figure 9 c) Dendrite growth was significantly suppressed, confirming the significant role of PPCOF in regulating lithium deposition. This was verified using COMSOL simulations, compared to LE ( Figure 10 a) E1M5 has a smaller potential difference, resulting in slower lithium dendrite growth. Figure 10 b), and after adding PPCOF ( Figure 10 c) The potential difference further narrows, dendrite growth slows down, and after the same deposition time, the dendrites are smaller, which also confirms the significant role of PPCOF in regulating lithium deposition. To further confirm the regulatory effect of PPCOF on lithium deposition, a current density of 0.5 mA cm⁻¹ was used. -2 The Li / / Li symmetric cell was disassembled after 50 cycles, and the SEI layer on the surface of the negative electrode Li was subjected to SEM testing. The results showed that compared with LE ( Figure 11 a) Although the lithium wafers after E1M5 cycling have a certain degree of flatness, obvious cracks can still be observed. Figure 11 b), while after adding the PPCOF cycle ( Figure 11 c) The lithium sheet surface is smooth and flat, without obvious protrusions or cracks, which further demonstrates the positive role of PPCOF in regulating lithium deposition.

[0090] In summary, this invention provides a dendrite-free gel polymer electrolyte prepared by using PMMA as the polymer matrix and adding PPCOF to regulate the electrochemical performance and lithium deposition of the electrolyte. Figure 1 Infrared spectroscopy revealed the disappearance of C=O and the appearance of C=N and NH in PPCOF, confirming the successful synthesis of PPCOF. Furthermore, SEM analysis was performed to further observe the morphology of PPCOF, and the results showed… Figure 1 b) It was found that the filler was spherical with a diameter of 2 μm; this can be obtained by small-angle XRD testing. Figure 1 c) The typical characteristic peaks of PPCOF confirm the successful synthesis of the porphyrin-based covalent organic framework (PPCOF). Figure 2 and Figure 3 The optimal molar ratio of MMA to TPTA was determined to be 5:1, and the optimal addition amount of PPCOF was determined to be 0.5 wt%. Figure 5 This indicates that the uniform dispersion of PPCOF in the polymer matrix is ​​beneficial to the formation of continuous phase lithium transport channels, thereby effectively improving electrochemical performance. Figure 6-8 ).pass Figure 9-11 This indicates that the addition of PPCOF can promote uniform lithium-ion deposition at the interface, reduce concentration polarization, and slow down dendrite growth. The SEI layer in Example 1 is also smoother and denser, which is also a result of uniform lithium-ion deposition. Example 1 exhibits excellent lithium stability; the assembled Li / / Li battery can cycle stably for nearly 10,000 hours at a current of 0.5 mA. Figure 12 The assembled Li / / LFP full cells also exhibited good rate performance and long cycle life, such as... Figure 13 As shown.

[0091] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a dendrite-free gel electrolyte, characterized in that: include, (1) Dissolve terephthalaldehyde in a solvent and stir; add pyrrole, trifluoroacetic acid and nitrobenzene, stir at room temperature to obtain a mixture; (2) Heat the mixture obtained in step (1) to 120-140°C and react continuously for 10-14 hours. After filtration and washing, filter the mixture to obtain a filter cake. (3) After vacuum drying the filter cake, a porphyrin-based covalent organic framework is obtained; (4) Add methyl methacrylate and ethoxylated trimethylolpropane triacrylate in a molar ratio of 4 to 6:1 to the LiDFOB electrolyte, mix and stir for 5 to 6 hours to obtain a mixed solution; (5) Add the porphyrin-based covalent organic framework to the mixed solution in step (4), stir for 5-6 hours, add the initiator to the mixed solution, stir for 20-30 minutes to obtain the precursor solution; (6) The precursor mixture solution is dropped onto both sides of the PP membrane to assemble Li / / Li or Li / / LFP batteries; (7) Heat in an oven at 50-60℃ for 10-12 hours to obtain dendrite-free gel electrolyte.

2. The method for preparing dendrite-free gel electrolyte according to claim 1, characterized in that: In step (1), the molar ratio of terephthalaldehyde to pyrrole is 1:

2.

3. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: In step (2), the reaction temperature is 130℃ and the reaction time is 12h.

4. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: In step (3), the drying includes drying the sample at 60°C.

5. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: In step (4), the molar ratio of methyl methacrylate and ethoxylated trimethylolpropane triacrylate is 5:

1.

6. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: In step (5), the porphyrin-based covalent organic framework accounts for 0.5 wt% of the weight in the mixed solution.

7. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: The solvent for the LiDFOB electrolyte is a mixture of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:

1.

8. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: In step (6), 30 μL of the precursor mixture solution is added to each side of the PP diaphragm.

9. The method for preparing dendrite-free gel electrolyte according to claim 1 or 2, characterized in that: In step (1), the solvent includes propionic acid.

10. The application of the dendrite-free gel electrolyte prepared by the method of claim 1 in a battery, characterized in that: The battery includes a lithium battery.

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