An ultra-stable flexible all-solid-state polymer electrolyte and its preparation method

Abstract

This invention provides an ultra-stable flexible all-solid-state polymer electrolyte and its preparation method. The all-solid-state polymer electrolyte is obtained by combining a homogeneous mixture of a polymer matrix, lithium salt, and crown ether with a porous support membrane. The ultra-stable flexible all-solid-state polymer electrolyte provided by this invention features high strength, good flexibility, and stable electrochemical performance. Lithium-lithium symmetric batteries assembled based on it exhibit excellent cycle stability and fast-charging properties. A pouch battery assembled using this ultra-stable flexible all-solid-state polymer electrolyte with a lithium iron phosphate cathode and a lithium metal anode can still function normally after multiple folding and shearing operations, and retains 90.41% of its capacity after 300 cycles at a current density of 0.1C.

Description

Technical Field

[0001] This invention belongs to the field of manufacturing technology of films or sheets containing polymeric substances, and specifically relates to an ultra-stable flexible all-solid-state polymer electrolyte and its preparation method. Background Technology

[0002] Currently, with the rapid development of portable devices, electric vehicles, and other fields, lithium-ion batteries have been widely used. However, commercially available lithium-ion batteries often use flammable, leak-prone, and toxic liquid carbonate electrolytes. Due to their unstable electrochemical performance and poor thermal stability, they are prone to accidents such as fires and explosions, limiting their further development. In recent years, solid-state electrolytes, which offer higher safety, higher energy density, and a wider operating temperature range, have become a research hotspot in the battery field.

[0003] Solid polymer electrolytes (SPEs) have become a trend in the industrialization of solid-state batteries in recent years due to their good processability, simple preparation process, low cost, and better safety. However, existing SPEs still have problems with ion transport and interface stability. It is well known that lithium ions in SPEs shuttle between solvation sites on the polymer chain, and the segmented movement of the polymer chain promotes lithium ion transport. However, this stable binding structure significantly restricts the movement of electrochemically active lithium ions. Unfortunately, most SPEs are crystalline, further limiting their applications. Furthermore, the shear modulus of SPEs is almost insufficient to suppress dendrite formation. Uncontrolled dendrite growth and stripping during repeated cycling leads to the formation of dead lithium, promoting side reactions between the SPE and the lithium anode, ultimately impairing battery performance. In addition, most SPEs have low room-temperature ionic conductivity, requiring operation at higher temperatures, which further reduces their elastic stiffness and increases the risk of dendrite puncture. Despite researchers in this field designing novel solid-state polymer electrolyte systems (polymer electrolyte matrix and lithium salt) and composite solid electrolytes containing polymers and inorganic fillers as additives to address ion transport and interfacial stability issues in polymer composite solid-state electrolytes, the synthesis of novel polymer electrolytes and lithium salts typically requires complex and time-consuming steps; the dispersibility of inorganic fillers limits their ability to improve the conductivity of solid polymer electrolytes; furthermore, the addition of other additives, such as liquid plasticizers or polymer plasticizers, can further soften the polymer electrolyte, thereby accelerating interfacial degradation. Therefore, constructing high-performance polymer electrolytes with stable performance that can be scalably applied to all-solid-state batteries is of great significance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing an ultra-stable flexible all-solid polymer electrolyte and its preparation method. The all-solid polymer electrolyte has advantages such as good electrochemical stability and large-scale preparation, and can solve the problems of poor ion transport and interface stability in existing polymer electrolytes.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0006] An ultra-stable flexible all-solid-state polymer electrolyte is provided, which is obtained by combining a homogeneous mixture of polymer matrix, lithium salt and crown ether with a porous support membrane.

[0007] According to the above scheme, the polymer matrix is ​​any one or more blends of polyvinyl oxide electrolyte, polyvinylidene fluoride electrolyte, polyacrylonitrile electrolyte, polyN-methacrylamide electrolyte, polymethacrylate electrolyte, polyvinyl carbonate electrolyte, polypropylene carbonate electrolyte, polyvinyl carbonate electrolyte, polyethylene carbonate electrolyte, polytetrahydrofuran electrolyte, polyester electrolyte, polyurethane electrolyte, poly(1,3-dioxolane) electrolyte, and polysiloxane electrolyte.

[0008] According to the above scheme, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, or lithium hexafluorophosphate.

[0009] One or more of lithium hexafluoroarsenate, lithium bis(oxalate-borate), lithium bis(fluorosulfonylimide), lithium di(fluorooxalate-borate), and lithium trifluoromethanesulfonate.

[0010] According to the above scheme, the crown ether is one or more of 12-crown ether-4, 15-crown ether-5, 18-crown ether-6, 21-crown ether-7, and 24-crown ether-8. By introducing crown ethers, this invention can, on the one hand, promote the dissolution of lithium salts, providing a higher lithium-ion concentration in the system; on the other hand, at the molecular and atomic level, the introduction of crown ethers disrupts the crystallization of the polymer electrolyte and weakens the coordination between the polymer and lithium ions, thereby promoting lithium-ion transport. Furthermore, due to the modulating effect of crown ethers, more anions enter the coordination structure of lithium ions and decompose on the negative electrode side to generate a protective solid electrolyte interface, reducing the risk of lithium dendrite puncture and improving interface stability.

[0011] According to the above scheme, the lithium salt accounts for 30-60% of the total mass of the polymer matrix, lithium salt and crown ether.

[0012] According to the above scheme, the crown ether accounts for 2 to 50% of the total mass of the polymer matrix, lithium salt and crown ether.

[0013] According to the above scheme, the porous support membrane is one of polyethylene terephthalate porous membrane, polyethylene porous membrane, polypropylene porous membrane, aramid porous membrane, polysulfonamide porous membrane, polyimide porous membrane, cellulose porous membrane, glass fiber porous membrane, and seaweed fiber porous membrane, with a thickness of 5-50 μm and a pore size of 20-200 nm.

[0014] This invention also includes a method for preparing the above-mentioned ultra-stable flexible all-solid-state polymer electrolyte, the specific steps of which are as follows:

[0015] 1) Add the polymer matrix, lithium salt and crown ether to the solvent, and heat and stir at 30-80℃ to obtain a polymer electrolyte dispersion;

[0016] 2) Lay the porous support membrane flat on a glass plate, and then uniformly coat the polymer electrolyte dispersion obtained in step 1) onto the porous support membrane to ensure that the polymer electrolyte dispersion completely penetrates into the pores of the porous support membrane. Then remove the solvent to obtain an ultra-stable flexible all-solid polymer electrolyte.

[0017] According to the above scheme, the solvent in step 1) is a mixture of one or more miscible components selected from methanol, ethanol, acetonitrile, tetrahydrofuran, dichloromethane, 1,3-dioxolane, N,N-dimethylformamide, and N-methylpyrrolidone.

[0018] According to the above scheme, in step 1), the total mass ratio of the polymer matrix, lithium salt and crown ether to the volume ratio of the solvent is 25 to 100 mg / mL.

[0019] According to the above scheme, the coating thickness of the polymer electrolyte dispersion on the porous support membrane in step 2) is 5-50 μm.

[0020] The present invention also includes the application of the above-mentioned ultra-stable flexible all-solid-state polymer electrolyte in batteries.

[0021] The present invention also includes a battery prepared based on the above-described ultra-stable flexible all-solid-state polymer electrolyte.

[0022] The beneficial effects of this invention are as follows: 1. The ultra-stable flexible all-solid-state polymer electrolyte provided by this invention has the characteristics of high strength, good flexibility, and stable electrochemical performance. Lithium-lithium symmetric batteries assembled based on it can achieve a speed of 0.1 mA / cm². 2The battery exhibits stable cycling stability for over 4360 hours at a current density of [insert value here]. Using lithium metal as the negative electrode and lithium iron phosphate as the positive electrode, the full battery, equipped with this ultra-stable flexible all-solid-state polymer electrolyte, retains 76.3% capacity after 1000 cycles at a 1C (1C = 170 mAh / g) current density and 90% capacity after 500 cycles at a 2C current density, demonstrating excellent cycle stability and fast-charging properties. A pouch battery assembled using this ultra-stable flexible all-solid-state polymer electrolyte with a lithium iron phosphate positive electrode and a lithium metal negative electrode continues to function normally after multiple folding and shearing operations, and retains 90.41% capacity after 300 cycles at a 0.1C current density. 2. The preparation method of this invention is simple to operate, low in cost, and can be mass-produced, which is beneficial for industrial production and commercial application. Attached Figure Description

[0023] Figure 1 This is a photograph of the ultra-stable flexible all-solid-state polymer electrolyte prepared in Example 1 of the present invention.

[0024] Figure 2 The lithium-lithium symmetric battery assembled with the ultra-stable flexible all-solid-state polymer electrolyte prepared in Example 1 was tested at 60°C and a current density of 0.1 mA / cm². 2 Long-cycle performance graph;

[0025] Figure 3 The graph shows the cycling performance of the full cell assembled with the ultra-stable flexible all-solid polymer electrolyte prepared in Example 1 at 60°C and a current density of 1C (1C = 170 mAh / g).

[0026] Figure 4 The graph shows the cycling performance of the full cell assembled with the ultra-stable flexible all-solid polymer electrolyte prepared in Example 1 at 60°C and 2C (1C = 170 mAh / g) current density.

[0027] Figure 5 The graph shows the cycling performance of the pouch cell assembled with the ultra-stable flexible all-solid-state polymer electrolyte prepared in Example 1 at 60°C and a current density of 0.1C (1C = 170 mAh / g).

[0028] Figure 6 The solid-state NMR comparison diagrams are of the all-solid-state polymer electrolyte prepared in Example 1 and the all-solid-state polymer electrolyte without crown ether in Comparative Example 1.

[0029] Figure 7 The Raman spectra of the all-solid-state polymer electrolyte prepared in Example 1 and the all-solid-state polymer electrolyte without crown ether in Comparative Example 1 are compared.

[0030] Figure 8The lithium-lithium symmetric battery assembled with the all-solid-state polymer electrolyte prepared for Comparative Example 1 was tested at 60 °C and a current density of 0.1 mA / cm². 2 Long-cycle performance graph;

[0031] Figure 9 The lithium-lithium symmetric battery assembled with the ultra-stable flexible all-solid-state polymer electrolyte prepared in Example 1 was tested at 60°C and a current density of 0.1 mA / cm². 2 Surface image of lithium sheet after 4360 hours of cycling;

[0032] Figure 10 The lithium-lithium symmetric battery assembled with the all-solid-state polymer electrolyte prepared for Comparative Example 1 was tested at 60 °C and a current density of 0.1 mA / cm². 2 Surface morphology of lithium wafers after 179 hours of cycling. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] Example 1

[0035] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0036] 1) Weigh 262 mg of polyethylene oxide, 213 mg of lithium bis(trifluoromethanesulfonyl)imide and 25 mg of 15-crown ether-5 and add them to 16 mL of anhydrous acetonitrile. Heat and stir at 60 °C to obtain a polymer electrolyte dispersion.

[0037] 2) In a dry environment, a 5μm thick polyethylene porous support membrane (purchased from Yuntianhua Co., Ltd.) was laid flat on a glass plate. Then, while it was still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support membrane. After casting, it was evenly coated with a scraper to ensure that the polymer electrolyte dispersion completely penetrated into the pores of the porous support membrane (the coating thickness was about 25μm). After most of the solvent evaporated at 40°C, it was placed in a vacuum drying oven and vacuum dried at 60°C for 12 hours to obtain an ultra-stable flexible all-solid polymer electrolyte.

[0038] A physical image of the ultra-stable flexible all-solid-state polymer electrolyte prepared in this embodiment is shown below. Figure 1 As shown, the product is transparent, and the pattern on the paper can be seen through the electrolyte. The thickness of the ultra-stable flexible all-solid polymer electrolyte was measured to be 32 μm, and the tensile strength was 144.95 MPa. It has the characteristics of thinness and good mechanical properties.

[0039] The ultra-stable flexible all-solid-state polymer electrolyte prepared in this embodiment was applied to the assembly of a lithium-lithium symmetric battery. Specifically, the ultra-stable flexible all-solid-state polymer electrolyte was sandwiched between two lithium metal sheets and placed inside a 2016-type coin cell casing. The casing was then pressurized and sealed using a manual sealing machine. The assembled lithium-lithium symmetric battery was tested at 60°C with an energy density of 0.1 mA / cm². 2 Current density, 0.1 mAh / cm 2 The energy density was subjected to constant current charge-discharge testing, and the results are as follows: Figure 2 As shown, the assembled lithium-lithium symmetric battery can cycle stably for more than 4360 hours without significant change in polarization voltage, indicating that it has extremely high interfacial stability with lithium metal.

[0040] The ultra-stable flexible all-solid-state polymer electrolyte prepared in this embodiment was applied to the assembly of an all-solid-state lithium metal battery. Specifically, the prepared ultra-stable flexible all-solid-state polymer electrolyte, lithium metal sheet, and lithium iron phosphate cathode sheet were sequentially placed into a 2016-type coin cell casing. The casing was then pressurized and sealed using a manual packaging machine. After assembly, a long-cycle charge-discharge test was conducted at 60°C, charging at 1C and 2C (1C = 170 mAh / g) rates to 4V and then discharging to 2.5V. The test results are as follows: Figure 3 and Figure 4 As shown in the figure, the full battery retains 76.3% of its capacity after 1000 cycles at a current density of 1C (1C = 170mAh / g); and 90% of its capacity after 500 cycles at a current density of 2C. It has excellent cycle stability and fast charging properties, and can be used in high-rate all-solid-state batteries.

[0041] The ultra-stable flexible all-solid-state polymer electrolyte prepared in this embodiment was applied to the assembly of an all-solid-state lithium metal pouch battery. Specifically, the prepared lithium iron phosphate cathode sheet, ultra-stable flexible all-solid-state polymer electrolyte, and lithium metal sheet were sequentially stacked and assembled. The assembly was then packaged using a pouch battery packaging machine. After assembly, a long-cycle charge-discharge test was performed at 60°C, charging to 4V at a rate of 0.1C (1C = 170 mAh / g) and then discharging to 2.5V. The test results are as follows: Figure 5 As shown, after 300 cycles at a current density of 0.1C, it still retains 90.41% of its capacity and can still function normally after multiple folding and shearing.

[0042] Comparative Example 1

[0043] A flexible all-solid polymer electrolyte is prepared in a manner similar to that of Example 1, except that 15-crown ether-5 is not added during the preparation process.

[0044] Figure 6This is a comparison of solid-state NMR spectra of the all-solid-state polymer electrolyte prepared in Example 1 and the all-solid-state polymer electrolyte without crown ether in this comparative example. It can be seen that after the addition of crown ether, the spectrum... 7 The lithium peak shifts to a higher field, indicating that the addition of crown ether weakens the coordination between the polymer and lithium ions.

[0045] Figure 7 The image shows a comparison of the Raman spectra of the all-solid polymer electrolyte prepared in Example 1 and the all-solid polymer electrolyte without crown ether in this comparative example. After adding crown ether, the content of coordinated anions in the system increases and the content of free anions decreases, indicating that the modulation effect of crown ether allows more anions to enter the coordination structure of lithium ions.

[0046] Figure 2 and Figure 8 The lithium-lithium symmetric batteries assembled with all-solid-state polymer electrolytes prepared in Example 1 and Comparative Example 1, respectively, were tested at 60°C and a current density of 0.1 mA / cm². 2 The long-term cycling performance graph shows that the sample of Example 1 can cycle stably for 4360 hours, while the sample of Comparative Example 1 can only cycle for 179 hours under the same conditions. This indicates that the addition of crown ether is beneficial to improving interfacial stability, thereby greatly improving the cycle life.

[0047] Figure 9 and Figure 10 The lithium-lithium symmetric batteries assembled with all-solid-state polymer electrolytes prepared in Example 1 and Comparative Example 1, respectively, were tested at 60°C and a current density of 0.1 mA / cm². 2 The microstructure of the lithium sheet surface after 4360h and 179h cycling is shown in the images. The lithium-lithium symmetric battery assembled with the ultra-stable flexible all-solid-state polymer electrolyte prepared in Example 1 still has a smooth lithium sheet surface after 4360h cycling, with no lithium dendrites generated. However, the lithium-lithium symmetric battery assembled with the ultra-stable flexible all-solid-state polymer electrolyte prepared in Comparative Example 1 has an uneven lithium sheet surface after only 179h cycling, with obvious lithium dendrite growth. The comparison shows that the addition of crown ether can generate a solid electrolyte interface with a protective function, reduce the risk of lithium dendrite puncture, and improve interface stability.

[0048] Example 2

[0049] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0050] 1) Weigh 248 mg of polyethylene oxide, 202 mg of lithium bis(trifluoromethanesulfonyl)imide and 50 mg of 15-crown ether-5 and add them to 12 mL of anhydrous acetonitrile. Heat and stir at 70 °C to obtain a polymer electrolyte dispersion.

[0051] 2) In a dry environment, a 16 μm thick polypropylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion to ensure complete penetration into the pores of the porous support film. After most of the solvent evaporated at 40°C, the film was placed in a vacuum drying oven at 60°C for 12 hours to obtain a 15 μm thick ultra-stable flexible all-solid polymer electrolyte. The room temperature ionic conductivity of this electrolyte was 2 × 10⁻⁶. -5 S / m.

[0052] Example 3

[0053] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0054] 1) Weigh 292 mg of polyethylene oxide, 158 mg of lithium bis(trifluoromethanesulfonyl)imide and 50 mg of 15-crown ether-5 and add them to 10 mL of anhydrous acetonitrile. Heat and stir to obtain a polymer electrolyte dispersion.

[0055] 2) In a dry environment, a 5 μm thick polyethylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion, ensuring complete penetration into the pores of the porous support film. After most of the solvent evaporated at 40°C, the film was placed in a vacuum drying oven at 60°C for 12 hours to obtain a 10 μm thick ultra-stable flexible all-solid polymer electrolyte with a tensile modulus of 58.12 MPa.

[0056] Example 4

[0057] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0058] 1) Weigh 220 mg of polyethylene oxide, 180 mg of lithium bis(trifluoromethanesulfonyl)imide and 100 mg of 15-crown ether-5 and add them to 10 mL of anhydrous acetonitrile. Heat and stir to obtain a polymer electrolyte dispersion.

[0059] 2) In a dry environment, a 25 μm thick polypropylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion, ensuring complete penetration into the pores of the porous support film. After most of the solvent evaporated at 40°C, the film was placed in a vacuum drying oven at 60°C for 12 hours to obtain a 30 μm thick ultra-stable flexible all-solid-state polymer electrolyte. The assembled lithium-lithium symmetric battery exhibited a current of 0.1 mA / cm² at 60°C. 2Current density, 0.1 mAh / cm 2 It can cycle stably for more than 1500 hours at the energy density, and the polarization voltage does not change significantly.

[0060] Example 5

[0061] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0062] 1) Weigh 262 mg of polyethylene oxide, 213 mg of lithium bis(trifluoromethanesulfonyl)imide and 25 mg of 12-crown ether-4 and add them to 16 mL of anhydrous acetonitrile. Heat and stir to obtain a polymer electrolyte dispersion.

[0063] 2) In a dry environment, a 20 μm thick polypropylene-polyimide support film was laid flat on a glass plate. Then, while still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion to ensure complete penetration into the pores of the porous support film. After most of the solvent evaporated at 40°C, the film was placed in a vacuum drying oven at 60°C for 12 hours to obtain a 25 μm thick ultra-stable flexible all-solid polymer electrolyte with a tensile modulus of 70.12 MPa.

[0064] Example 6

[0065] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0066] 1) Weigh 262 mg of polyethylene oxide, 213 mg of lithium bis(trifluoromethanesulfonyl)imide and 25 mg of 18-crown ether-6 and add them to 16 mL of anhydrous acetonitrile. Heat and stir to obtain a polymer electrolyte dispersion.

[0067] 2) In a dry environment, a 5 μm thick polyethylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion to ensure complete penetration into the pores of the porous support film. After most of the solvent evaporated at 40°C, the film was placed in a vacuum drying oven at 60°C for 12 hours to obtain a 35 μm thick polyethylene ultra-stable flexible all-solid polymer electrolyte. The room temperature ionic conductivity of this electrolyte was 1.12 × 10⁻⁶. -5 S / m.

[0068] Example 7

[0069] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0070] 1) Weigh 300 mg of polyvinylidene fluoride, 150 mg of lithium bis(trifluoromethanesulfonyl)imide and 50 mg of 15-crown ether-5 and add them to 5 mL of N,N-dimethylformamide. Heat and stir to obtain a polymer electrolyte dispersion.

[0071] 2) In a dry environment, a 5μm thick polyethylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion, ensuring complete penetration into the pores of the porous support film. After most of the solvent evaporated at 80℃, the film was placed in a vacuum drying oven at 120℃ for 24 hours to obtain a 7μm thick ultra-stable flexible all-solid-state polymer electrolyte. The assembled lithium-lithium symmetric battery exhibited a current of 0.1 mA / cm² at 50℃. 2 Current density, 0.1 mAh / cm 2 It can cycle stably for more than 500 hours at the energy density, and the polarization voltage does not change significantly.

[0072] Example 8

[0073] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0074] 1) Weigh 300 mg of polyvinylidene fluoride, 150 mg of lithium perchlorate and 50 mg of 18-crown ether-6 and add them to 5 mL of N,N-dimethylformamide. Heat and stir to obtain a polymer electrolyte dispersion.

[0075] 2) In a dry environment, a 5μm thick polyethylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion to ensure complete penetration into the pores of the porous support film. After most of the solvent evaporated at 80℃, the film was placed in a vacuum drying oven at 120℃ for 24 hours to obtain an ultra-stable, flexible, all-solid-state polymer electrolyte with an elongation at break of 173.30%.

[0076] Example 9

[0077] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0078] 1) Weigh 300 mg of polyvinylidene fluoride-hexafluoropropylene, 150 mg of lithium perchlorate and 50 mg of 21-crown ether-7 and add them to 5 mL of N,N-dimethylformamide. Heat and stir to obtain a polymer electrolyte dispersion.

[0079] 2) In a dry environment, a 5 μm thick polyethylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion to ensure complete penetration into the pores of the porous support film. After most of the solvent evaporated at 80°C, the film was placed in a vacuum drying oven at 120°C for 24 hours to obtain a 17 μm thick ultra-stable flexible all-solid polymer electrolyte with a room temperature ionic conductivity of 1.84 × 10⁻⁶. -5 S / m.

[0080] Example 10

[0081] An ultra-stable flexible all-solid-state polymer electrolyte is prepared by the following steps:

[0082] 1) Weigh 300 mg of polyacrylonitrile, 150 mg of lithium difluorosulfonyl imide and 50 mg of 24-crown ether-8 and add them to 5 mL of N,N-dimethylformamide. Heat and stir to obtain a polymer electrolyte dispersion.

[0083] 2) In a dry environment, a 16 μm thick polypropylene support film was laid flat on a glass plate. While still hot, the polymer electrolyte dispersion obtained in step 1) was poured onto the porous support film. After casting, a scraper was used to evenly spread the dispersion to ensure complete penetration into the pores of the porous support film. After most of the solvent evaporated at 80°C, the film was placed in a vacuum drying oven at 120°C for 24 hours to obtain a 19 μm thick ultra-stable flexible all-solid polymer electrolyte with a room temperature ionic conductivity of 1.36 × 10⁻⁶. -5 S / m.

[0084] The above embodiments are merely preferred embodiments for further illustrative purposes and are not intended to limit the implementation. Those skilled in the art will recognize that other improvements and modifications can be made without departing from the inventive principles described above. It is neither necessary nor possible to exhaustively list all possible examples here. Obvious improvements and modifications based on the inventive principles of this invention are still considered within the scope of protection of this invention.

Claims

1. An ultra-stable flexible all-solid-state polymer electrolyte, characterized in that, It is obtained by combining a polymer matrix, lithium salt and crown ether uniformly mixed with a porous support membrane, wherein the crown ether is 15-crown ether-5.

2. The ultra-stable flexible all-solid-state polymer electrolyte according to claim 1, characterized in that, The polymer matrix is ​​any one or more blends of polyvinyl oxide electrolyte, polyvinylidene fluoride electrolyte, polyacrylonitrile electrolyte, poly(N-methacrylamide) electrolyte, polymethacrylate electrolyte, polyvinyl carbonate electrolyte, polypropylene carbonate electrolyte, polyethylene carbonate electrolyte, polyethylene carbonate electrolyte, polytetrahydrofuran electrolyte, polyester electrolyte, polyurethane electrolyte, poly(1,3-dioxolane) electrolyte, and polysiloxane electrolyte.

3. The ultra-stable flexible all-solid-state polymer electrolyte according to claim 1, characterized in that, The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium bis(oxalateborate), lithium bis(fluorosulfonyl)imide, lithium difluorooxalateborate, and lithium trifluoromethanesulfonate; the lithium salt accounts for 30-60% of the total mass of the polymer matrix, lithium salt, and crown ether.

4. The ultra-stable flexible all-solid-state polymer electrolyte according to claim 1, characterized in that, The crown ether accounts for 2 to 50% of the total mass of the polymer matrix, lithium salt, and crown ether.

5. The ultra-stable flexible all-solid-state polymer electrolyte according to claim 1, characterized in that, The porous support membrane is one of the following: polyethylene terephthalate porous membrane, polyethylene porous membrane, polypropylene porous membrane, aramid porous membrane, polysulfonamide porous membrane, polyimide porous membrane, cellulose porous membrane, glass fiber porous membrane, and seaweed fiber porous membrane, with a thickness of 5~50μm and a pore size of 20~200nm.

6. A method for preparing the ultra-stable flexible all-solid-state polymer electrolyte according to any one of claims 1-5, characterized in that, The specific steps are as follows: 1) Add the polymer matrix, lithium salt and crown ether to the solvent, and heat and stir at 30~80℃ to obtain a polymer electrolyte dispersion; 2) Lay the porous support membrane flat on a glass plate, and then uniformly coat the polymer electrolyte dispersion obtained in step 1) onto the porous support membrane to ensure that the polymer electrolyte dispersion completely penetrates into the pores of the porous support membrane. Then remove the solvent to obtain an ultra-stable flexible all-solid polymer electrolyte.

7. The method for preparing the ultra-stable flexible all-solid-state polymer electrolyte according to claim 6, characterized in that, Step 1) The solvent is a mixture of one or more miscible components selected from methanol, ethanol, acetonitrile, tetrahydrofuran, dichloromethane, 1,3-dioxolane, N,N-dimethylformamide, and N-methylpyrrolidone; Step 1) The total mass ratio of the polymer matrix, lithium salt, and crown ether to the volume ratio of the solvent is 25~100 mg / mL.

8. The method for preparing the ultra-stable flexible all-solid-state polymer electrolyte according to claim 6, characterized in that, Step 2) The coating thickness of the polymer electrolyte dispersion on the porous support membrane is 5~50μm.

9. The application of the ultra-stable flexible all-solid-state polymer electrolyte according to any one of claims 1-5 in batteries.

10. A battery prepared from an ultra-stable flexible all-solid-state polymer electrolyte according to any one of claims 1-5.

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