A gel electrolyte film capable of reducing side reactions inside a battery and a method for preparing the same

Abstract

The application discloses a gel electrolyte film capable of reducing internal side reactions of a battery and a preparation method thereof, and comprises the following steps: uniformly mixing trifluoroethyl methacrylate (TFMA) and an organic solvent TEP in a volume ratio of 3-4:6-7 in an inert atmosphere to obtain a mixed solution; adding lithium salt lithium bis-trifluoromethanesulfonimide (LiTFSI) and / or lithium difluoro(oxalato)borate (LiDFOB) into the mixed solution, and then adding an initiator and uniformly mixing to obtain a precursor solution; dropping the precursor solution on a cellulose film, assembling a semi-finished battery in the order of a negative electrode, the cellulose film loaded with the precursor solution and a positive electrode, heating at 60-80 DEG C for 12-24 h, and obtaining an in-situ polymerized gel electrolyte film. Since there is interaction between the polymer framework PTFMA and the organic solvent TEP, the proportion of the organic solvent TEP in a free state in the system is greatly reduced, thereby reducing the side reactions of TEP occurring at the lithium metal negative electrode and the positive electrode side, and effectively improving the cycle life of the battery.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery electrolyte technology, specifically relating to a gel electrolyte membrane that can reduce internal side reactions in batteries and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Research on lithium metal rechargeable batteries has been ongoing for nearly half a century. However, the organic electrolytes widely used in lithium metal batteries have physical properties such as volatility and flammability, which can easily lead to battery combustion or even explosions. In contrast to the safety hazards of organic electrolytes, solid electrolytes do not leak or volatilize, possess a certain mechanical strength, are not easily flammable, and have good mechanical properties and thermal stability, resulting in better safety and reliability. Among solid electrolyte systems, polymer-based solid electrolytes have better interfacial contact and compatibility than oxide- and sulfide-based electrolytes, and also exhibit higher air stability.

[0004] Various polymer electrolyte matrices for lithium metal batteries have been developed, including PVDF, PEO, PPC, and PVDF-HFP. However, due to the traditional complexation-decomplexation conduction mechanism between lithium ions and polymer segments, most pure polymer electrolytes exhibit low lithium-ion transference numbers and lithium-ion conductivity at room temperature. This leads to slow lithium-ion transport kinetics, resulting in capacity decay and poor cycle performance.

[0005] While existing gel electrolytes can solve the problem of low lithium-ion conductivity faced by traditional polymer electrolytes to some extent, the introduction of a large amount of organic solvents inevitably leads to redox decomposition at the positive / negative electrode interface, resulting in an increase in lithium-ion transport resistance at the interface. Furthermore, due to their own flammability, the flammability of the entire electrolyte system is increased. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a gel electrolyte membrane that can reduce internal side reactions in batteries and its preparation method.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a gel electrolyte that can reduce internal side reactions in a battery, comprising the following steps:

[0009] Trifluoroethyl methacrylate (TFMA) and organic solvent TEP were mixed evenly in an inert atmosphere at a volume ratio of 1-8:1-8 to obtain a mixture.

[0010] After adding lithium salts lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and / or lithium difluorooxalate borate (LiDFOB) to the mixture, an initiator is added and the mixture is stirred evenly to obtain the precursor solution.

[0011] The precursor liquid is dropped onto the cellulose membrane, and the semi-finished battery is assembled in the order of negative electrode - cellulose membrane loaded with precursor liquid - positive electrode. The battery is heated at 60-80℃ for 12-24 hours to obtain an in-situ polymerized gel electrolyte membrane.

[0012] A gel electrolyte is obtained by in-situ polymerization of the polymer precursor TFMA in a precursor fluid via a free radical addition reaction initiated by an initiator. The organic solvent TEP used in this preparation method possesses strong flame retardancy, and the flammability of the prepared gel electrolyte does not increase due to the introduction of the organic electrolyte, thus significantly improving the safety of the gel electrolyte in use.

[0013] The gel electrolyte of the present invention significantly reduces the proportion of free organic solvent TEP in the system due to the interaction between the polymer framework TFMA and the organic solvent triethyl phosphate (TEP). This reduces the side reactions of TEP on the lithium metal anode and cathode sides, thereby effectively improving the cycle life of the battery.

[0014] The present invention, through multiple adjustments of lithium salt concentration and polymer-organic solvent ratio, obtains a gel electrolyte that, under the condition of being able to form independently, possesses high lithium-ion conductivity.

[0015] The preparation method of the gel polymer electrolyte provided by the present invention is not the same as that of the prior art, which involves preparing the polymer electrolyte in advance and then assembling the battery. Instead, it adopts an in-situ polymerization method, that is, before the electrolyte solution has polymerized to form an independently shaped gel electrolyte, a fixed volume is measured and assembled into the battery, so that the polymerization reaction occurs inside the battery during the heating process.

[0016] In some embodiments, trifluoroethyl methacrylate (TFMA) and organic solvent TEP are in a volume ratio of 3-4:6-7.

[0017] In some embodiments, the content of both H2O and O2 in the inert atmosphere is less than 0.1 ppm.

[0018] In some embodiments, the volume ratio of TFMA to TEP is 3.5:6.5. This ratio ensures both good formability of the gel electrolyte and effectively improves lithium-ion conductivity.

[0019] In some embodiments, lithium salts lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium difluorooxalate borate (LiDFOB) are added to the mixture, wherein the concentration of LiTFSI is 0.2-2.5 M and the concentration of LiDFOB is 0.2-0.5 M.

[0020] In some embodiments, the initiator is azobisisobutyronitrile (AIBN).

[0021] In some embodiments, AIBN accounts for 1%-2% of the mass of the precursor fluid.

[0022] In some embodiments, the thickness of the cellulose membrane is 25-40 μm.

[0023] Preferably, the thickness of the gel electrolyte membrane is 80-100 μm.

[0024] Secondly, the present invention provides a gel electrolyte membrane that can reduce internal side reactions of a battery, which is prepared by the aforementioned preparation method.

[0025] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0026] 1. This invention, through multiple adjustments to the lithium salt concentration and polymer-organic solvent ratio, yields a gel electrolyte with high lithium-ion conductivity while maintaining the ability to form independently. If the TFMA:TEP ratio is too low, it may be difficult to obtain a self-forming gel after the final heating step; conversely, if the TFMA:TEP ratio is too high, the prepared gel will have excessively low lithium-ion conductivity due to the low solvent ratio. By rationally controlling the ratio of polymer framework, organic solvent, and lithium salt, the lithium-ion transport kinetics of the gel electrolyte are effectively improved, thereby significantly enhancing the cycle stability and specific capacity of lithium metal batteries.

[0027] 2. The gel electrolyte prepared by this invention has high flame retardancy, effectively improving the safety of battery operation. Unlike the ether-based and ester-based organic electrolytes used in traditional lithium-ion batteries, which have extremely high flammability, the introduced organic solvent TEP is often used as a phosphorus-based flame retardant, thus effectively reducing the risk of thermal runaway during battery operation, improving safety and stability.

[0028] 3. The gel electrolyte prepared in this invention exhibits excellent stability against both lithium metal anodes and lithium cobalt oxide cathodes. Most organic solvents are unstable and prone to side reactions with lithium metal anodes, as well as decomposition when used with high-voltage cathode materials. This invention, through the design of the gel electrolyte, instills intermolecular interactions between the polymer framework and the organic solvent. These interactions anchor some of the free solvent, reducing side reactions with the lithium metal anode and making it more suitable for LiCoO2-type cathodes. The reduction of free TEP solvent is significant for stabilizing both the lithium metal anode and cathode, minimizing internal battery side reactions, and improving cycle stability. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1 The image shows the SEM image and mapping of the gel electrolyte after polymerization in Example 1.

[0031] Figure 2 The infrared absorption spectra of the gel electrolytes and their respective precursors obtained in Example 1 and Comparative Example 1 are shown.

[0032] Figure 3 The room temperature impedances are those measured by assembling SS / / SS cells in Examples 1-9 and Comparative Example 1. Specifically, a represents the room temperature impedance measured by assembling SS / / SS cells in Examples 1-8, b represents the room temperature impedance measured by assembling SS / / SS cells in Example 9, and c represents the room temperature impedance measured by assembling SS / / SS cells in Comparative Example 1.

[0033] Figure 4 Flame retardancy measured for Example 1(a) and Comparative Example 1(b).

[0034] Figure 5 The graph shows a comparison of the lithium cycling stability measured by assembling Li / / Li symmetric cells in Example 1 and Comparative Example 1.

[0035] Figure 6 The cycle life is given by the Li / / Li symmetric cell assembled with gel electrolyte as in Comparative Example 2.

[0036] Figure 7 The graph shows a comparison of the cycling stability measured for the assembled Li / / LCO full cells of Example 1 and Comparative Example 1.

[0037] Figure 8The infrared absorption spectra of the gel electrolytes prepared in Examples 1-4 without the addition of lithium salts and the infrared absorption spectra of pure TEP are shown. The gel materials referred to as 35TFMA-65TEP do not contain lithium salts, and TFMA:TEP = 35:65 (V:V).

[0038] Figure 9 for Figure 8 Peak fitting results of infrared absorption peaks of relevant samples. Detailed Implementation

[0039] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0040] Room temperature: This has a generally accepted meaning, specifically referring to 25-25℃;

[0041] The present invention will be further described below with reference to the embodiments.

[0042] Example 1

[0043] A method for preparing a gel electrolyte membrane that can reduce internal side reactions in a battery includes the following steps:

[0044] (1) The polymer precursor trifluoroethyl methacrylate (TFMA) and the organic solvent TEP were mixed in a glove box at room temperature at a ratio of 35:65 (volume ratio) and stirred for 0.5 h to mix evenly.

[0045] (2) Add 0.5M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 0.5M lithium difluorooxalate borate (LiDFOB), and 2 wt% of the initiator azobisisobutyronitrile (AIBN) to the mixed solution obtained in step (1), and stir at room temperature for 0.5 h to obtain the polymer precursor liquid.

[0046] (3) Cut the purchased NKK-TF4030 cellulose diaphragm into 16mm round pieces using a punching machine, and dry them in a glove box for 24 hours for later use.

[0047] Take 50 μL of the precursor liquid obtained in step (2) and add it to the cellulose membrane. Assemble the semi-finished battery in the order of negative electrode - cellulose membrane loaded with precursor liquid - positive electrode. Then heat the semi-finished battery at 60°C for 12 h to obtain an in-situ polymerized gel electrolyte membrane inside the battery.

[0048] Example 2

[0049] This embodiment is basically the same as Example 1, except that: in step (1), the polymer precursor trifluoroethyl methacrylate (TFMA) and the organic solvent TEP are mixed in a glove box at room temperature in a ratio of 40:60 (volume ratio).

[0050] Example 3

[0051] This embodiment is basically the same as Example 1, except that: in step (1), the polymer precursor trifluoroethyl methacrylate (TFMA) and the organic solvent TEP are mixed in a glove box at room temperature in a ratio of 60:40 (volume ratio).

[0052] Example 4

[0053] This embodiment is basically the same as Example 1, except that: in step (1), the polymer precursor trifluoroethyl methacrylate (TFMA) and the organic solvent TEP are mixed in a glove box at room temperature in a ratio of 80:20 (volume ratio).

[0054] Example 5

[0055] This embodiment is basically the same as that of embodiment 1, except that the concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) added in step (2) is 0.2 M.

[0056] Example 6

[0057] This embodiment is basically the same as that of embodiment 1, except that the concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) added in step (2) is 1M.

[0058] Example 7

[0059] This embodiment is basically the same as that of embodiment 1, except that the concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) added in step (2) is 1.5M.

[0060] Example 8

[0061] This embodiment is basically the same as that of embodiment 1, except that the concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) added in step (2) is 2M.

[0062] Example 9

[0063] This embodiment is basically the same as that of embodiment 1, except that the concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) added in step (2) is 2.5M.

[0064] Comparative Example 1

[0065] A method for preparing a gel electrolyte for lithium metal batteries includes the following steps:

[0066] This comparative example is basically the same as Example 1, except that the polymer precursor added in step (1) is ethyl methacrylate (HEMA).

[0067] Comparative Example 2

[0068] A method for preparing a gel electrolyte for lithium metal batteries includes the following steps:

[0069] This comparative example is basically the same as Example 1, except that the lithium salt added in step (2) is a single LiTFSI with a concentration of 1M.

[0070] To test the electrochemical performance, flame retardancy, and cycle stability of the gel electrolyte materials obtained in Examples 1-9 and Comparative Examples 1-2, the specific methods are as follows:

[0071] (1) Synthesis and morphology characterization: The gel electrolyte obtained by in-situ polymerization was removed from the battery for morphological observation (SEM) and infrared spectroscopy (FT-IR) testing. Figure 1 The synthesized gel electrolyte has a smooth surface and uniform elemental distribution. According to... Figure 2 After being heated at 60℃ for 12 hours, it is located at 1600-1650cm. -1 The disappearance of the infrared absorption peak related to the C=C stretching vibration proves that this condition can successfully induce in-situ polymerization.

[0072] (2) Lithium-ion conductivity: The electrolyte was assembled into a symmetrical battery of "stainless steel sheet / electrolyte / stainless steel sheet". Electrochemical impedance spectroscopy was measured using an electrochemical workstation at a frequency of 0.1 Hz to 1000 kHz and a temperature of 25 °C. The ionic conductivity (σ) was calculated using the following formula:

[0073]

[0074] In the formula, L is the electrolyte membrane thickness, R is the electrolyte resistance obtained from impedance spectroscopy, and S is the electrode area.

[0075] Figure 3 Table 1 shows the room temperature impedance measured after assembling SS / / SS batteries in Examples 1-9 and Comparative Example 1, respectively. Table 1 also shows the calculated room temperature lithium-ion conductivity of Examples 1-9. Based on experiments, the highest solubility of LiDFOB using a dual lithium salt design is 0.5 M; therefore, its concentration was kept constant to investigate the effects of the contents of LiTFSI, TFMA, and TEP on the lithium-ion conductivity of the system.

[0076] Table 1. Lithium-ion conductivity calculated from the room temperature impedance of SS / / SS batteries measured in Examples 1-9.

[0077]

[0078]

[0079] according to Figure 3 As shown in Table 1, the lithium-ion conductivity decreases at the same lithium salt concentration as the proportion of polymer framework in the gel electrolyte increases while the content of organic solvent decreases. However, when the proportions of polymer framework and organic solvent in the gel electrolyte and the concentration of LiDFOB remain constant, the lithium-ion conductivity of the resulting gel electrolyte shows a trend of first increasing and then decreasing with increasing LiTFSI concentration. The highest lithium-ion conductivity, approximately 0.933 mS / cm, is achieved when the LiTFSI concentration is 0.5 M. Therefore, for all embodiments, Example 1 yielded the highest room-temperature lithium-ion conductivity, with a composition of 0.5 M LiTFSI, 0.5 M LiDFOB, and TFMA:TEP = 35:65 (V:V). The gel electrolyte obtained in Example 1 is denoted as SGPE, and the gel electrolyte in Comparative Example 1 is denoted as CGPE.

[0080] (3) Flame retardancy test: The time taken for the gel electrolyte materials described in Example 1 and Comparative Example 1 to extinguish from ignition was tested, and their flammability was compared. Figure 4 Combustion tests were conducted on the gel electrolyte materials described in Example 1 and Comparative Example 1 at different times. The gel electrolyte in Example 1, after ignition for 3 seconds, exhibited self-extinguishing flame after the heat source was removed, indicating that the designed gel electrolyte of Example 1 has good flame retardant properties. The gel electrolyte in Comparative Example 1, after ignition for 3 seconds, continued to burn after the flame was removed, indicating relatively poor flame retardancy compared to Example 1. Example 1 and Comparative Example 1 used different polymer frameworks, resulting in differences in their flame retardancy. This suggests that the polymer framework PTFMA used in Example 1 has better flame retardancy than the polymer framework PHEMA used in Comparative Example 1.

[0081] (4) Lithium Cycle Stability Test: NKK-TF4030 cellulose membrane was pre-cut into 16mm round pieces and stored in a glove box for 24 hours for later use. The lithium metal sheet had a diameter of 15.6mm and a thickness of 0.45μm. A 2032-type button cell semi-finished product was assembled using the lithium metal sheet, a cellulose membrane loaded with 50μL of electrolyte precursor as the electrolyte, and the lithium metal sheet as the electrode-electrolyte-electrode sequence. The resulting semi-finished battery was heated at 60℃ for 12 hours to obtain the final Li / / Li symmetric cell. 0.1mA / cm 2 0.05mAh / cm 2 The lithium symmetric batteries corresponding to Example 1 and Comparative Example 1 were cycled at current density and capacity density, and their performance was as follows: Figure 5As shown, the battery assembled using Example 1 has a cycle life of 1000 hours, which is significantly better than the cycle life of the Li / / Li symmetric battery assembled using Comparative Example 1. This indicates that the gel electrolyte prepared in Example 1 has better lithium stability and fewer side reactions with lithium metal sheets during cycling.

[0082] The Li / / Li symmetric battery assembled using the gel electrolyte in Comparative Example 2 has the following cycle life: Figure 6 As shown, under the same experimental conditions, its cycle life is significantly lower than that of the Li / / Li symmetric battery assembled with gel electrolyte in Example 1. This indicates that the combined use of LiTFSI and LiDFOB dual lithium salts can maximize the improvement of the electrolyte's lithium cycle stability compared to the use of a single lithium salt at the same concentration. This suggests that the use of dual lithium salts generates a protective SEI interface during cycling, preventing continuous side reactions between the electrolyte and the lithium metal anode.

[0083] (5) Cyclic stability test of Li / / LCO full cell: The active material, conductive agent, and binder were mixed in NMP solvent at a mass ratio of 8:1:1. Super P was used as the conductive agent and PVDF as the binder. After stirring evenly, the mixture was coated onto aluminum foil and vacuum dried at 80°C for 12 hours. The resulting material was then cut into small round pieces with a diameter of 14 mm to serve as the positive electrode. NKK-TF4030 cellulose membrane was pre-cut into 16 mm round pieces and stored in a glove box for later use. Using the above-obtained round pieces as the positive electrode, Li metal sheets as the negative electrode, and 50 μL of electrolyte precursor loaded on the cellulose membrane as the electrolyte, CR2032 button cells were assembled sequentially to obtain a semi-finished battery. The semi-finished battery was heated at 60°C for 12 hours to obtain the finished battery. All battery assembly (H2O and O2 contents were both below 0.1 ppm) was completed under glove box conditions. During testing, the Li / / LiCoO2 battery was cycled at a constant current charge-discharge rate of 0.2C at room temperature. The measured cycle data are as follows: Figure 7 As shown, the Li / / LCO full cell assembled in Example 1 had an initial cycle capacity of approximately 139.84 mAh / g (second cycle), and after more than 200 cycles, the capacity reached 106.11 mAh / g, with a capacity retention of approximately 76%. In contrast, the Li / / LCO full cell assembled in Comparative Example 1 not only had a lower initial discharge capacity but also experienced rapid capacity decay. This indicates that when the two electrolytes are applied to the high-voltage LCO cathode, the side reactions of the gel electrolyte in Comparative Example 1 are more pronounced, meaning that the gel electrolyte corresponding to Example 1 is more suitable for the high-voltage cathode.

[0084] (6) Verification of intermolecular forces of gel electrolyte in Example 1: Infrared spectroscopy was performed on samples TEP, 35TFMA-65TEP, 40TFMA-60TEP, 60TFMA-40TEP, and 80TFMA-20TEP. The results are as follows: Figure 8As shown. According to Figure 8 The P=O absorption peak of pure TEP is at ~1260 cm⁻¹. -1 A peak appears at the wavenumber. As the proportion of the polymer framework increases and the proportion of the organic solvent TEP decreases, the peak shift of the P=O absorption peak of TEP becomes more pronounced. The peak position of sample 80TFMA-20TEP shifts to ~1278 cm⁻¹. -1 At the wavenumber, this indicates that the poly(trifluoroethyl methacrylate) polymer framework can exert intermolecular interactions on triethyl phosphate, thereby affecting its molecular state. In contrast, adjusting the ratio of the poly(trifluoroethyl methacrylate) polymer framework to the organic solvent triethyl phosphate did not result in a significant shift in the P=O absorption peak, indicating that the intermolecular forces between the two are negligible. Therefore, the lithium cycling stability and LCO cycling stability of the gel electrolyte in Comparative Example 1 are lower than those in Example 1.

[0085] Detailed peak fitting results for samples 35TFMA-65TEP, 40TFMA-60TEP, 60TFMA-40TEP, and 80TFMA-20TEP are as follows: Figure 9 As shown, even though the proportion of the polymer framework PTFMA decreases and the proportion of TEP increases, resulting in a decrease in the intermolecular forces of the polymer framework on TEP, detailed peak fitting results for samples 35TFMA-65TEP show that TEP in an anchored state still accounts for a very high proportion, approximately 55%. This significantly reduces the proportion of freely mobile solvents participating in side reactions in Example 1.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a gel electrolyte that can reduce internal side reactions in a battery, characterized in that: Includes the following steps: Trifluoroethyl methacrylate (TFMA) and organic solvent TEP were mixed evenly in an inert atmosphere at a volume ratio of 3-4:6-7 to obtain a mixture. After adding lithium salts lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium difluorooxalate borate (LiDFOB) to the mixture, an initiator is added and the mixture is stirred evenly to obtain the precursor solution. The precursor liquid is dropped onto the cellulose membrane, and the semi-finished battery is assembled in the order of negative electrode - cellulose membrane loaded with precursor liquid - positive electrode. The battery is heated at 60-80℃ for 12-24 hours to obtain an in-situ polymerized gel electrolyte membrane.

2. The method for preparing a gel electrolyte that reduces internal side reactions in a battery according to claim 1, characterized in that: In the inert atmosphere, the contents of both H2O and O2 are less than 0.1 ppm.

3. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 1, characterized in that: The volume ratio of trifluoroethyl methacrylate (TFMA) to organic solvent TEP is 3.5:6.

5.

4. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 1, characterized in that: Lithium salts lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium difluorooxalate borate (LiDFOB) were added to the mixture.

5. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 1, characterized in that: The concentrations of LiTFSI and LiDFOB in the mixture were 0.2-2.5 M and 0.2-0.5 M, respectively.

6. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 1, characterized in that: The initiator is azobisisobutyronitrile (AIBN).

7. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 6, characterized in that: AIBN accounts for 1%-2% of the mass of the precursor fluid.

8. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 1, characterized in that: The thickness of the cellulose membrane is 25-40 μm.

9. The method for preparing a gel electrolyte that reduces internal side reactions of a battery according to claim 1, characterized in that: The thickness of the gel electrolyte membrane is 80-100 μm.

10. A gel electrolyte membrane capable of reducing internal side reactions in a battery, characterized in that: It is prepared by any one of the preparation methods described in claims 1-9.

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