A non-perfluoropolymer material, a method for preparing the same and its use in lithium metal batteries

Abstract

The application discloses a non-perfluoropolymer material, a preparation method thereof and application of the non-perfluoropolymer material in a lithium metal battery, and belongs to the technical field of lithium batteries. A lithium salt, a crosslinking agent, a non-perfluoropolymer monomer and an ester solvent are uniformly mixed to obtain a precursor solution, an initiator is added, and a non-perfluoropolymer material precursor solution is obtained. The non-perfluoropolymer material precursor solution is dropped on a diaphragm, the diaphragm is assembled into a battery, and then heating is performed to complete the reaction, so that the non-perfluoropolymer material is generated in situ on the diaphragm. The non-perfluoropolymer monomer is 2,2,3,3-tetrafluoropropyl methacrylate, the crosslinking agent is trimethylolpropane triacrylate, the volume ratio of the non-perfluoropolymer monomer to the crosslinking agent is (1-1000):(1000-1), and the total volume of the crosslinking agent and the non-perfluoropolymer monomer accounts for 1-99% of the total volume of the crosslinking agent, the non-perfluoropolymer monomer and the ester solvent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer electrolyte preparation, and particularly relates to a non-perfluoropolymer material, a preparation method thereof and application thereof in lithium metal batteries. BACKGROUND

[0002] Lithium (Li) metal has a high theoretical capacity, about ten times that of the traditional graphite anode (3860 mAh g -1 vs 372 mAh g -1 ), and is therefore considered to be the most promising high-energy-density lithium metal battery anode material.

[0003] Compared with liquid and all-solid-state electrolytes, cross-linked network gel polymer electrolytes (GPEs) provide an effective solution to improve the interfacial reaction stability and safety of metal-based batteries (such as lithium metal batteries and sodium metal batteries) with high theoretical energy density. However, the low Li + ionic conductivity and Li + + transference number of GPEs still limit the rate and stability of chemical reactions at the electrode, resulting in low actual energy density and short cycle life of the battery. In the past few decades, in order to improve the safety of the battery, GPEs such as polycarbonates and polyethers have been developed, and better cycle life has been achieved by changing the cross-linked network structure and introducing functional additives. However, improving the ionic conductivity of GPEs is still a challenge for building lithium batteries with high energy capacity and long life. The lack of in-depth understanding of the conduction mechanism and transfer path of Li + + in GPEs is the reason why the ionic transfer rate is difficult to improve.

[0004] The present application forms a weak hydrogen bond between the non-perfluoromonomer (TFM) containing EWG and the anion, clarifies the influence of the regulation of the polymer skeleton on the ion transport in the ion transport process, and significantly improves the ion transference number and ionic conductivity in the PTFM. Excellent electrochemical / chemical stability is exhibited under long cycle of high load cathode.

[0005] The present application first proves that intermolecular hydrogen bonds are formed in GPEs, effectively limiting the migration of anions, improving the cation transference number and ionic conductivity. Notably, the present study reveals the influence mechanism of cation / anion interaction on the ionic conductivity of GPEs through "preparation of a non-perfluoropolymer material", which is of great significance for the development of high-performance and high-safety batteries. SUMMARY

[0006] To solve the deficiencies of the prior art, the purpose of the present application is to provide a non-perfluoropolymer material, a preparation method thereof and its application in lithium metal batteries. The present application uses 2,2,3,3-tetrafluoropropyl methacrylate (TFM) molecules as non-perfluoropolymer monomers to construct a quasi-solid-state electrolyte of non-perfluoropolymer material, studies the interaction between the backbone and lithium salt anion in the non-perfluorinated electrolyte material containing electron-withdrawing groups (EWG), limits the invalid migration of anions, and significantly improves the ion migration number and ionic conductivity in PTFM. Excellent electrochemical / chemical stability is shown under long cycle of high load positive electrode.

[0007] Based on the above purpose, the present application adopts the following technical scheme:

[0008] A preparation method of a non-perfluoropolymer material, the process is as follows: mixing lithium salt, crosslinking agent, non-perfluoropolymer monomer and ester solvent uniformly to obtain a precursor solution, adding an initiator to obtain a non-perfluoropolymer material precursor solution, dropping the non-perfluoropolymer material precursor solution on a separator, and assembling the separator with the non-perfluoropolymer material precursor solution into a battery, then heating to complete the reaction, i.e. generating a non-perfluoropolymer material in situ on the separator;

[0009] The non-perfluoropolymer monomer is 2,2,3,3-tetrafluoropropyl methacrylate, the crosslinking agent is trimethylolpropane triacrylate, the volume ratio of the non-perfluoropolymer monomer to the crosslinking agent is (1~1000):(1000~1), and the total volume of the crosslinking agent and the non-perfluoropolymer monomer accounts for 1~99% of the total volume of the crosslinking agent, the non-perfluoropolymer monomer and the ester solvent.

[0010] Further, the lithium salt is one or more of lithium bis(trifluoromethylsulfonyl)imide (LiN(CF3SO2)2), lithium bisfluorosulfonylimide (LiNF2(SO2)2), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium difluoro(oxalato)borate (LiDFOB), and the concentration of the lithium salt in the precursor solution is 0.5~2 mol / L. Preferably, the lithium salt is lithium bis(trifluoromethylsulfonyl)imide (LiN(CF3SO2)2).

[0011] Further, the initiator is one of cyclohexanone peroxide, azobisisobutyronitrile, azobisisoheptyl nitrile and a photoinitiator, and the addition amount of the initiator is 0.5~2.0 wt% of the precursor solution. The present application uses azobisisobutyronitrile as the initiator.

[0012] Further, the ester solvent is a mixture of two or three of ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), and fluoroethylene carbonate (FEC) in any ratio. Preferably, a mixture of two or three of ethylene carbonate (EC), diethyl carbonate (DEC), and fluoroethylene carbonate (FEC) is used as the solvent, and the volume ratio of the three is (1-100):(1-100):(1-100). Specifically, a mixture of diethyl carbonate (DEC) and fluoroethylene carbonate (FEC) in a volume ratio of 4:1 is used as the solvent.

[0013] Further, the heating temperature is 50-70°C, and the heating time is 6-24 h.

[0014] Further, the amount of the non-perfluoropolymer material precursor solution added to the separator is 50-500 μL / cm 2 .

[0015] The non-perfluoropolymer material is prepared by the above method.

[0016] The non-perfluoropolymer material is used in a lithium metal battery, which comprises a lithium metal as the negative electrode, a substrate coated with a positive active material as the positive electrode, a separator between the positive and negative electrodes, and the separator is impregnated with the non-perfluoropolymer material precursor solution.

[0017] The positive electrode is prepared by dissolving the positive active material, conductive agent, and binder in NMP and then coating the mixture on a substrate. The conductive agent is one or more of Ketjen black, carbon nanotube, super P, and conductive carbon black. The positive active material is one or more of lithium iron phosphate, nickel-cobalt-manganese ternary material 811, nickel-cobalt-manganese ternary material 622, and nickel-cobalt-manganese ternary material 532. The binder is one or more of polyvinylidene fluoride, sodium hydroxymethyl cellulose, and polyethylene oxide. The conductive agent accounts for 5-10 wt% of the total weight of the positive active material, conductive agent, and binder, and the binder accounts for 5-10 wt% of the total weight of the positive active material, conductive agent, and binder.

[0018] The separator is a glass fiber separator, and 50 μL of the non-perfluoropolymer material precursor solution is added to the surface of the glass fiber separator to obtain a separator impregnated with the non-perfluoropolymer material precursor solution. The diameter of the separator is 16 mm, and the thickness of the polymerized separator is 25 μm.

[0019] The substrate can be a conductive substrate commonly used in the battery field, such as an aluminum foil. The electrode area can be a commonly used electrode area, such as an area of 1.13 cm 2The positive active material loaded on the substrate can be commonly used in the battery field, such as lithium iron phosphate, nickel cobalt manganese, etc., and the conductive agent has various choices, such as carbon nanotubes, ketjen black, graphene, and the like. Taking the ketjen black as an example, the preparation process of the lithium iron phosphate positive electrode is as follows: the ketjen black, polyvinylidene fluoride and lithium iron phosphate are uniformly mixed in N-methyl-2-pyrrolidone, and then uniformly drawn on an aluminum foil by a four-side preparation device. The electrode is heated at 80°C under vacuum for 10 hours, and the lithium iron phosphate positive electrode is obtained. The proportion of the lithium iron phosphate material, the ketjen black and the polyvinylidene fluoride is 8:1:1, and the loading mass of the lithium iron phosphate can be selected according to different types of batteries. For example, when the button battery is 2032, the loading mass of the lithium iron phosphate is controlled to be 20 mg / cm2.

[0020] The preparation process of the nickel cobalt manganese 811 positive electrode is as follows: the ketjen black, polyvinylidene fluoride and nickel cobalt manganese 811 are uniformly mixed in N-methyl-2-pyrrolidone, and then uniformly drawn on an aluminum foil by a four-side preparation device. The electrode is heated at 80°C under vacuum for 10 hours, and the lithium iron phosphate positive electrode is obtained. The proportion of the lithium iron phosphate material, the ketjen black and the polyvinylidene fluoride is 8:1:1, and the loading mass of the lithium iron phosphate can be selected according to different types of batteries. For example, when the button battery is 2032, the loading mass of the lithium iron phosphate is controlled to be 20 mg / cm2.

[0021] The lithium metal battery of the non-perfluoropolymer material is obtained by the above method.

[0022] The application of the non-perfluoropolymer material in the lithium metal battery significantly improves the safety performance of the lithium metal battery due to the unique flame-retardant effect of the gel polymer electrolyte PTFM. Meanwhile, in the cycle process, the non-perfluoropolymer monomer material 2,2,3,3-tetrafluoropropyl methacrylate (TFM) acts as a multifunctional unit, and weak hydrogen bonds are formed through the interaction between the EWG in the non-perfluoropolymer and the anion. The interaction between lithium ions and anions is weakened, the Li + ion conductivity is improved, the uniform deposition of lithium ions is promoted, and the occurrence of side reactions is reduced.

[0023] The application can adjust the binding strength of the EWG and the lithium salt anion by designing and synthesizing a series of cross-linked polyesters with different electron-withdrawing groups (EWG). The interaction between the EWG and the anion is enhanced, and weak hydrogen bonds are formed. The interaction between lithium ions and anions is weakened, which is the key reason for the improvement of Li + ion conductivity. The results show that the Li + transfer number and the ion conductivity of the GPE (PTFM) added with (2,2,3,3-tetrafluoropropyl methacrylate) are the highest, which are 0.85 and 0.78 mS cm −1 , respectively, which are much higher than 0.53 and 0.14 mS cm −1The cycle life of Li / / PTFM / / NCM811 battery is 5 times of Li / / PMMA / / NCM811 battery, and the battery capacity is 5.5 mAh cm −2 . In addition, the energy density of graphite / / PTFM / / NCM811 pouch battery is 220 Wh kg −1 , and the capacity retention rate is 92% after 520 cycles. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 are the structural schematic diagrams of monomer and polymerization;

[0025] Figure 2 are the optical photos of GPE: (a) photo of GPE after polymerization, (b) infrared spectrum of GPE before and after polymerization;

[0026] Figure 3 are the electrochemical tests of GPE: (a) is the ion conductivity test of GPE, (b) is the ion transference number test of GPE;

[0027] Figure 4 are the solvent nuclear magnetic resonance spectrum analysis of MMA, MMA / Li + , TFM, TFM / Li + ;

[0028] Figure 5 are the molecular dynamics simulations of GPE (PMMA) and GPE (PTFM): (a, b) are the binding energies of GPE with anion (LFSI - ), (c, d) are the binding energies of GPE with lithium ion, (e) is the distance between C-H in TFM and C-F in TFSI, (f) is the distance between C-H in MMA and C-F in TFSI, (g) is the radial distribution function of Li-O (TFSI) in GPE, (h) is the ion diffusion coefficient;

[0029] Figure 6 are the half-cell performance tests: (a) is the cycle performance test of lithium symmetric battery, the current density is 0.5 mA cm -2 , the capacity is 2 mAh cm -2 , (b) is the cycle performance test of lithium symmetric battery, the current density is 1 mA cm -2 , the capacity is 1 mAh cm -2 ;

[0030] Figure 7For full battery performance test: (a) lithium iron phosphate as the positive electrode, lithium metal as the negative electrode, GPE-containing battery long cycle performance test, (b) NCM811 as the positive electrode, lithium metal as the negative electrode, GPE-containing battery long cycle performance test; the red and blue above represent the coulombic efficiency of different cycle numbers, the red and blue below represent the cycle capacity of different cycle numbers, Li||LiFePO4 and Li||NCM811 batteries are assembled for comparison. DETAILED DESCRIPTION

[0031] In order to make the technical objects, technical solutions and excellent effects of the present application clearer, the technical solutions of the present application will be further described below in combination with the drawings and specific examples.

[0032] Material source: ethyl methyl carbonate (EMC), fluoroethylene carbonate (FEC), configured as a liquid electrolyte in a volume ratio of 8:2, lithium bis (trifluoromethyl sulfonyl imide) (LiTFSI), all the above materials are purchased from Suzhou Dodd Chemical Co., Ltd., China. The water content of the solvent is less than 20 ppm, and the water content of the lithium salt is less than 40 ppm. 2,2,3,3-tetrafluoropropyl methacrylate (TFM), methyl methacrylate (MMA) are purchased from Macklin Chemical Co., Ltd. Lithium iron phosphate, nickel-cobalt-manganese ternary material 811, Ketjen black are purchased from Kurun Chemical Co., Ltd. The glass fiber separator is a battery grade separator, model: whatman battery separator 1822-090.

[0033] The argon gas used in the experiment has a purity of 99.999%. All the materials used for battery assembly are stored in an argon-filled glove box.

[0034] Example 1:

[0035] A lithium symmetric battery assembly method of a non-perfluoropolymer material, the process is as follows:

[0036] (1) Electrolyte preparation: the non-perfluoropolymer monomer 2,2,3,3-tetrafluoropropyl methacrylate (TFM) and the crosslinking agent trimethylolpropane triacrylate (TPA) were mixed uniformly at a volume ratio of 1:1, then the mixed solution of monomers and crosslinking agent was mixed again with ester solvent (volume ratio, EMC:FEC=8:2) at a volume ratio of 1:9, and then LiTFSI and azobisisobutyronitrile (AIBN) were added, so that the concentration of LiTFSI in the total liquid of monomers, crosslinking agents and ester solvents was 1 mol / L, and the amount of azobisisobutyronitrile added was 0.5% of the total mass of monomers, crosslinking agents and ester solvents. The non-fluoropolymer monomer methyl methacrylate (MMA) and the crosslinking agent trimethylolpropane triacrylate (TPA) were first mixed uniformly at a volume ratio of 1:1, then the mixed solution of monomers and crosslinking agent was mixed again with ester solvent (volume ratio, EMC:FEC=8:2) at a volume ratio of 1:9, and then LiTFSI and azobisisobutyronitrile (AIBN) were added, so that the concentration of LiTFSI in the total liquid of monomers, crosslinking agents and ester solvents was 1 mol / L, and the amount of azobisisobutyronitrile added was 0.5% of the total mass of monomers, crosslinking agents and ester solvents. The structures of TFM, TPA and MMA are shown in detail in Figure 1 .

[0037] (2) Assembly: the battery was assembled in an argon-filled glove box, lithium was selected as the positive and negative electrode, the positive and negative electrodes were separated by a glass fiber separator, 50 μL of the non-perfluoropolymer electrolyte precursor solution or non-fluoropolymer electrolyte precursor solution prepared in (1) was dropped on the glass fiber separator, and the battery was assembled and packaged, and then heated at 60°C for 6 h after packaging (the diameter of the separator was 16 mm, and the thickness of the polymerized product was 25 μm), and the TFM and TPA in the non-perfluoropolymer electrolyte precursor were polymerized to form PTFM, and the MMA and TPA in the non-fluoropolymer electrolyte precursor were polymerized to form PMMA. The structures of PTFM and PMMA are shown in detail in Figure 1 . The physical photos of PTFM and PMMA after polymerization are shown in Figure 2 (a), and the infrared spectra of monomers MMA, TFM and polymers PMMA, PTFM after polymerization are shown in Figure 2 (b), Figure 2 (a) shows that the polymerized electrolyte does not flow when inverted, Figure 2 (b) the infrared spectrum shows that the C=C characteristic peak at 1630 cm -1 disappears in the polymerized electrolyte, indicating that the monomers are completely polymerized.

[0038] The ion transference number and ionic conductivity of the non-fluorine gel polymer electrolyte PMMA and the non-perfluorine gel polymer electrolyte PTFM were detected at room temperature, as shown in Figure 3 , the ion transference number of the non-fluorine gel polymer electrolyte PMMA was 0.53 and the ionic conductivity was 0.14 mS cm -1 at room temperature, and the ion transference number and ionic conductivity of the non-perfluorine gel polymer electrolyte PTFM containing EWG were 0.85 and 0.78 mS cm -1 .

[0039] The nuclear magnetic resonance spectrum analysis was carried out by adding LiTFSI into the MMA and TFM solvents and the mixed solvents (the concentration of LiTFSI in the solvents was 1 mol / L) into the MMA and TFM solvents respectively, and it was found that, different from the H chemical environment in the MMA, the H in -CF2CF2H in the TFM had an interaction with TFSI, so that the chemical shift was shifted to the high field. Figure 4

[0040] The molecular dynamics of the GPE(PMMA) and GPE(PTFM) were simulated, and the results are shown in Figure 5 , it was found by the molecular dynamics simulation that the distance between C-H in the TFM and C-F in the TFSI was only 3.8 Å, which belonged to weak hydrogen bond. It was further concluded that the weak hydrogen bond was formed by adjusting the binding strength of the EWG and the lithium salt anion, so as to affect the interaction between the lithium ion and the anion, and then improve the Li ion transference number and ionic conductivity.

[0041] The battery performance was tested at room temperature under the current density of 0.5 mA cm -2 , the capacity of 2 mAh cm -2 and the current density of 1 mA cm -2 , and the capacity of 1 mAh cm -2 , and the results are shown in Figure 6 . As shown in Figure 6 , under the current density of 1 mA cm -2 and the capacity of 1 mAh cm -2 , the Li||PTFM||Li battery could be stably operated for more than 1800 h. In comparison, the Li||PMMA||Li symmetric battery was operated for 400 h. Under the current density of 0.5 mA cm -2 and the capacity of 2 mAh cm -2 ​Under the same conditions, the Li||PTFM||Li cell can be operated stably for more than 2000 h. In contrast, the Li||PMMA||Li symmetric cell can only be operated for less than 400 h. The reason for its good cycle stability is mainly due to the high number of example migration and ionic conductivity of PTFM, uniform deposition during lithium ion cycling, thereby inhibiting the occurrence of side reactions.

[0042] Example 2:

[0043] A method for assembling a lithium-iron phosphate battery of a non-perfluoropolymer material, the process is as follows:

[0044] (1) Preparation of the positive electrode: lithium iron phosphate material, polyvinylidene fluoride, and Ketjen black are uniformly mixed in N-methyl-2-pyrrolidone at a mass ratio of 8:1:1, then uniformly drawn on an aluminum foil with a four-sided preparation device, and the electrode is heated at 80°C under vacuum for 10 h. The loading mass of lithium iron phosphate is controlled at ~20 mg / cm2;

[0045] (2) Preparation of the electrolyte: same as step (1) of Example 1.

[0046] (3) Take 50 μL of the prepared non-perfluoropolymer electrolyte precursor solution or fluorine-free polymer electrolyte precursor solution and drop it on the glass fiber separator;

[0047] (4) Assembly: the battery is assembled in an argon-filled glove box, lithium is selected as the negative electrode, the positive and negative electrodes are separated by the glass fiber separator of step (3), and after assembly and packaging, it is heated at 60°C for 6 h. The battery performance is tested at room temperature.

[0048] Example 3:

[0049] A method for assembling a lithium-ternary nickel-cobalt-manganese 811 battery of a non-perfluoropolymer material, the process is as follows:

[0050] (1) Preparation of the positive electrode: ternary nickel-cobalt-manganese 811 material, polyvinylidene fluoride, and Ketjen black are uniformly mixed in N-methyl-2-pyrrolidone at a mass ratio of 8:1:1, then uniformly drawn on an aluminum foil with a four-sided preparation device, and the electrode is heated at 80 o C, vacuum for 10 h, the loading mass of ternary nickel-cobalt-manganese 811 is controlled at ~20 mg / cm2;

[0051] (2) Preparation of the electrolyte: same as step (1) of Example 1.

[0052] (3) Take 50 μL of the prepared non-perfluoropolymer electrolyte precursor solution or fluorine-free polymer electrolyte precursor solution and drop it on the glass fiber separator;

[0053] (4) Assembly: The battery was assembled in an argon-filled glove box, lithium was selected as the negative electrode, the positive electrode and the negative electrode were separated by the glass fiber separator of step (3), and after assembly and packaging, it was heated at 60°C for 6 h. The performance of the battery was tested at room temperature.

[0054] Assembly of different types of batteries: The battery was assembled in an argon-filled glove box, lithium was selected as the negative electrode, the positive electrode and the negative electrode were separated by the glass fiber separator of step (3), and after assembly and packaging, it was heated at 60°C for 6 h. The performance of the battery was tested at room temperature.

[0055] The performance of the battery containing GPE with lithium iron phosphate as the positive electrode and lithium metal as the negative electrode prepared in Example 2 and the battery containing GPE with NCM811 as the positive electrode and lithium metal as the negative electrode prepared in Example 3 was tested, and the results are shown in Figure 7 , and Figure 7 It can be seen that at a high load, the PTFM battery with lithium iron phosphate as the positive electrode and the NCM811 battery with NCM811 as the positive electrode can be stably cycled for 650 cycles and 280 cycles, respectively. In comparison, the battery with PMMA as the electrolyte and lithium iron phosphate as the positive electrode was significantly attenuated in capacity after 200 cycles, and the battery with NCM811 as the positive electrode was significantly attenuated in capacity after 100 cycles.

[0056] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a non-perfluoropolymer material, characterized in that, The process is as follows: A precursor solution is obtained by uniformly mixing lithium salt, crosslinking agent, non-perfluoropolymer monomer and ester solvent. An initiator is added to obtain a non-perfluoropolymer material precursor solution. The non-perfluoropolymer material precursor solution is dropped onto a separator. After assembling the separator with the non-perfluoropolymer material precursor solution into a battery, the reaction is heated to complete, that is, non-perfluoropolymer material is generated in situ on the separator. The non-perfluoropolymer monomer is 2,2,3,3-tetrafluoropropyl methacrylate, and the crosslinking agent is trimethylolpropane triacrylate. The volume ratio of the non-perfluoropolymer monomer to the crosslinking agent is 1:1, and the total volume of the crosslinking agent and the non-perfluoropolymer monomer accounts for 1 to 99% of the total volume of the crosslinking agent, the non-perfluoropolymer monomer, and the ester solvent.

2. The method for preparing the non-perfluoropolymer material according to claim 1, characterized in that, The lithium salt is one or more of lithium hexafluorophosphate, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(fluorosulfonyl)imide, and the concentration of the lithium salt in the precursor solution is 0.5~2 mol / L.

3. The method for preparing the non-perfluoropolymer material according to claim 1, characterized in that, The initiator is one or more of cyclohexanone peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, and photoinitiators, and the amount of initiator added is 0.5~2.0 wt% of the precursor solution.

4. The method for preparing the non-perfluoropolymer material according to claim 1, characterized in that, The ester solvent is a mixture of two or three of the following in any proportion: ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, propylene carbonate, and fluoroethylene carbonate.

5. The method for preparing the non-perfluoropolymer material according to claim 1, characterized in that, The heating temperature is 50~70℃, and the heating time is 6~24 h.

6. The method for preparing the non-perfluoropolymer material according to claim 1, characterized in that: The amount of non-perfluoropolymer precursor solution added to the membrane is 50~500 μL / cm. 2 .

7. The non-perfluoropolymer material prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the non-perfluoropolymer material according to claim 7 in lithium metal batteries, characterized in that, Using lithium as the negative electrode, a current collector coated with a positive electrode active material is used as the positive electrode. The positive and negative electrodes are separated by a membrane with a non-perfluoropolymer precursor solution dropped on it. After assembly and encapsulation, the reaction is heated to complete, and the product is obtained.

9. The application according to claim 8, characterized in that, The preparation process of the positive electrode is as follows: the positive electrode active material, conductive agent, and binder are dissolved in NMP and then coated onto a substrate; the conductive agent is one or more of Ketjen black, carbon nanotubes, and conductive carbon black; the positive electrode active material is one or more of lithium iron phosphate, nickel-cobalt-manganese ternary material 811 (NCM811), nickel-cobalt-manganese ternary material 622, and nickel-cobalt-manganese ternary material 532; the binder is one or more of polyvinylidene fluoride, sodium hydroxymethyl cellulose, and polyethylene oxide; the conductive agent accounts for 5-10 wt% of the total weight of the positive electrode active material, conductive agent, and binder, and the binder accounts for 5-10 wt% of the total weight of the positive electrode active material, conductive agent, and binder.

10. The application according to claim 8, characterized in that, The diaphragm is a glass fiber diaphragm, and the substrate is aluminum foil.

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