Solid-state electrolyte membrane, method for preparing the same, and use thereof

Abstract

The application relates to a solid-state electrolyte film and a preparation method and application thereof. The solid-state electrolyte film comprises a main body film and a filling material; the main body film comprises a porous substrate layer, a first ceramic layer and a second ceramic layer, the first ceramic layer and the second ceramic layer are arranged on two opposite surfaces of the porous substrate layer respectively; the material of the porous substrate layer comprises expanded polytetrafluoroethylene; the material of the first ceramic layer comprises a first ceramic electrolyte material, the material of the second ceramic layer comprises a second ceramic electrolyte material, and the first ceramic electrolyte material and the second ceramic electrolyte material are different; the pores of the porous substrate layer, the first ceramic layer and the second ceramic layer are all filled with the filling material, and the filling material comprises at least one of lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a solid electrolyte, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries possess significant advantages such as high energy density, high efficiency, and long lifespan. These characteristics have led to their widespread application in energy storage systems, particularly in balancing power system loads and storing unstable energy sources like solar and wind power. With the global energy structure transformation and the rapid development of clean energy technologies, lithium-ion batteries, as the core of electrochemical energy storage technology, have seen technological breakthroughs that have not only improved energy density, cycle life, and safety performance but also expanded the application areas of hybrid and novel energy storage technologies. However, safety issues remain a major obstacle to the large-scale application of lithium-ion batteries, especially the widespread combustion and explosion accidents caused by thermal runaway. Lithium-ion battery thermal runaway refers to the accelerated chemical reactions occurring inside the battery under abnormal conditions, leading to a rapid rise in temperature and potentially causing serious accidents such as fires or explosions. This phenomenon is typically caused by a variety of factors, including internal short circuits, overcharging, mechanical damage, external heating, and battery aging.

[0003] Internal short circuits are a major cause of battery thermal runaway. Currently, mainstream lithium-ion batteries still use liquid electrolytes, which account for approximately 20% of the battery's weight. During battery operation, lithium ions in liquid electrolytes tend to deposit unevenly at the interface, forming lithium dendrites that can easily puncture the battery separator, leading to internal short circuits. When an internal short circuit occurs, the current path within the battery is altered, causing localized overheating and heat accumulation, which can easily trigger safety accidents. Developing solid-state electrolytes is a viable approach to overcome these problems.

[0004] However, traditional solid electrolyte membranes still struggle to balance high initial thermal runaway temperature, high ionic conductivity, and good contact stability. Summary of the Invention

[0005] Therefore, it is necessary to provide a solid electrolyte membrane, its preparation method, and its application. The solid electrolyte membrane of this application can simultaneously achieve a high initial thermal runaway temperature, high ionic conductivity, and good contact stability.

[0006] In a first aspect, this application provides a solid electrolyte membrane, comprising a main membrane and a filling material; the main membrane comprises a porous substrate layer, a first ceramic layer, and a second ceramic layer, wherein the first ceramic layer and the second ceramic layer are respectively disposed on two opposing surfaces of the porous substrate layer; the porous substrate layer is made of expanded polytetrafluoroethylene; the first ceramic layer is made of a first ceramic electrolyte material, the second ceramic layer is made of a second ceramic electrolyte material, and both the first and second ceramic electrolyte materials independently comprise Li 1.5 Al 0.5 Ti 1.5 (PO4)3, Li7La3Zr2O 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 6.75 La3Zr 1.75 Ta 0.25 O 12 And Li 1.5 Al 0.5 Ge 1.5 The material comprises at least one of (PO4)3, and the first ceramic electrolyte material and the second ceramic electrolyte material are different; the pores of the porous substrate layer, the first ceramic layer and the second ceramic layer are all filled with the filling material, and the filling material includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0007] In some embodiments, the thickness of the porous substrate layer is 2 μm to 18 μm.

[0008] In some embodiments, the pore size of the porous substrate layer is 0.3 μm to 8 μm.

[0009] In some embodiments, the porosity of the porous substrate layer is 60% to 85%.

[0010] In some embodiments, the material of the first ceramic layer further includes a first oxide additive.

[0011] In some embodiments, the material of the second ceramic layer further includes a second oxide additive.

[0012] In some embodiments, the first oxide additive includes at least one of silicon dioxide and aluminum oxide.

[0013] In some embodiments, the second oxide additive includes at least one of silicon dioxide and aluminum oxide.

[0014] In some embodiments, the material of the first ceramic layer also includes a polymer material.

[0015] In some embodiments, the material of the second ceramic layer also includes a polymer material.

[0016] In some embodiments, the filler material further includes a polymer material.

[0017] In some embodiments, the polymer material includes at least one of poly(vinylidene fluoride-hexafluoropropylene), polyacrylonitrile, and polyacrylic acid.

[0018] Secondly, this application provides a method for preparing a solid electrolyte membrane, comprising the following steps:

[0019] A porous substrate layer is provided, wherein the material of the porous substrate layer includes expanded polytetrafluoroethylene;

[0020] A first ceramic layer and a second ceramic layer are respectively prepared on two opposing surfaces of the porous substrate layer. The material of the first ceramic layer includes a first ceramic electrolyte material, and the material of the second ceramic layer includes a second ceramic electrolyte material. The first ceramic electrolyte material and the second ceramic electrolyte material include Li. 1.5 Al 0.5 Ti 1.5 (PO4)3, Li7La3Zr2O 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 6.75 La3Zr 1.75 Ta 0.25 O 12 And Li 1.5 Al 0.5 Ge 1.5 At least one of (PO4)3, and the first ceramic electrolyte material and the second ceramic electrolyte material are different;

[0021] A filling material is filled into the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer, wherein the filling material includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0022] In some embodiments, after filling the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer with the filler material, the following steps are further included:

[0023] The solid electrolyte membrane is subjected to hot pressing treatment.

[0024] In some embodiments, the temperature of the hot pressing process is 60°C to 120°C.

[0025] In some embodiments, the pressure of the hot pressing process is 2 MPa to 10 MPa.

[0026] Thirdly, this application provides a solid-state battery, including a solid electrolyte membrane as described in any one of the above claims or a solid electrolyte membrane prepared by any one of the above claims' preparation methods.

[0027] In the aforementioned solid electrolyte membrane, a porous substrate layer comprising expanded polytetrafluoroethylene (ePTFE) is used as the main substrate. ePTFE possesses excellent non-flammability, and its thermal runaway temperature can reach over 340°C, far exceeding that of other traditional polymer battery separators, significantly improving the thermal runaway temperature of the solid electrolyte membrane. Simultaneously, ePTFE has continuous pores that can be filled by the solid electrolyte. The solid electrolyte material filling the pores of ePTFE effectively inhibits lithium dendrite growth and prevents lithium dendrites from penetrating the electrolyte layer. Furthermore, the first and second ceramic layers on the two opposing surfaces of the porous substrate layer serve as contact layers with the positive and negative electrodes of the battery, respectively. This application uses a ceramic electrolyte material with more stable electrochemical performance as the contact layer. Moreover, the first and second ceramic electrolyte materials are different; during battery fabrication, the ceramic layer with relatively higher conductivity contacts the positive electrode, while the ceramic layer with relatively lower conductivity contacts the negative electrode, thereby improving the stability of the contact between the solid electrolyte membrane and the negative electrode. Furthermore, in the solid electrolyte membrane, a filler material with high ionic conductivity is used to fill the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer. This ensures the stability of the contact interface while also enabling the solid electrolyte membrane to have high overall ionic conductivity. The solid electrolyte membrane of this application can simultaneously achieve a high initial thermal runaway temperature, high ionic conductivity, and good contact stability. Attached Figure Description

[0028] Figure 1 A scanning electron microscope image of the porous substrate layer provided in Embodiment 1 of this application;

[0029] Figure 2 This is a cross-sectional view of the solid electrolyte membrane in Embodiment 1 of this application;

[0030] Figure 3 Thermogravimetric analysis (TGA) of the solid electrolyte membrane in Embodiment 1 of this application;

[0031] Figure 4 This is a diagram showing the electrochemical stability window of the solid electrolyte membrane in Example 1 of this application;

[0032] Figure 5The discharge specific capacity diagram of the LiFePO4 / / Li battery corresponding to the solid electrolyte membrane in Example 1 of this application under charge and discharge conditions of 0.1C, 0.2C, 0.5C and 1C. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] The applicant discovered that traditional solid electrolyte membranes, primarily using conventional battery separators (such as polyethylene and polypropylene membranes), typically have thermal runaway temperatures below 150°C. Even with composite solid electrolyte membranes, it is difficult to raise the thermal runaway temperature above 200°C. Furthermore, in schemes attempting to increase the thermal runaway temperature through composite solid electrolyte membranes, the ionic conductivity of the composite solid electrolyte is relatively low, typically less than 1×10⁻⁶. -4 Scm -1 Meanwhile, traditional solid electrolyte membranes also suffer from short battery life and rapid failure. The applicant discovered that rapid battery failure is mainly due to the difference in reaction between the positive and negative electrodes. For example, when the same solid electrolyte material is used to contact both the positive and negative electrodes, the lithium metal negative electrode is prone to reacting with the solid electrolyte, leading to its decomposition.

[0039] To address the aforementioned problems, one embodiment of this application provides a solid electrolyte membrane, comprising a main membrane and a filling material; the main membrane includes a porous substrate layer, a first ceramic layer, and a second ceramic layer, the first ceramic layer and the second ceramic layer being respectively disposed on two opposing surfaces of the porous substrate layer; the porous substrate layer is made of expanded polytetrafluoroethylene; the first ceramic layer is made of a first ceramic electrolyte material, the second ceramic layer is made of a second ceramic electrolyte material, and both the first and second ceramic electrolyte materials independently comprise Li. 1.5 Al 0.5 Ti 1.5 (PO4)3, Li7La3Zr2O 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 6.75 La3Zr 1.75 Ta 0.25 O 12 And Li 1.5 Al 0.5 Ge 1.5The first ceramic electrolyte material and the second ceramic electrolyte material are different from each other; the pores of the porous substrate layer, the first ceramic layer and the second ceramic layer are filled with a filling material, which includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0040] In the aforementioned solid electrolyte membrane, a porous substrate layer comprising expanded polytetrafluoroethylene (ePTFE) is used as the main substrate. ePTFE possesses excellent non-flammability, and its thermal runaway temperature can reach over 340°C, far exceeding that of other traditional polymer battery separators, significantly improving the thermal runaway temperature of the solid electrolyte membrane. Simultaneously, ePTFE has continuous pores that can be filled by the solid electrolyte. The solid electrolyte material filling the pores of ePTFE effectively inhibits lithium dendrite growth and prevents lithium dendrites from penetrating the electrolyte layer. Furthermore, the first and second ceramic layers on the two opposing surfaces of the porous substrate layer serve as contact layers with the positive and negative electrodes of the battery, respectively. This application uses a ceramic electrolyte material with more stable electrochemical performance as the contact layer. Moreover, the first and second ceramic electrolyte materials are different; during battery fabrication, the ceramic layer with relatively higher conductivity contacts the positive electrode, while the ceramic layer with relatively lower conductivity contacts the negative electrode, thereby improving the stability of the contact between the solid electrolyte membrane and the negative electrode. Furthermore, in the solid electrolyte membrane, a filler material with high ionic conductivity is used to fill the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer. This ensures the stability of the contact interface while also enabling the solid electrolyte membrane to have high overall ionic conductivity. The solid electrolyte membrane of this application can simultaneously achieve a high initial thermal runaway temperature, high ionic conductivity, and good contact stability.

[0041] It is understandable that the difference between the first ceramic electrolyte material and the second ceramic electrolyte material means that the first ceramic electrolyte material and the second ceramic electrolyte material are not completely identical. That is, when both the first ceramic electrolyte material and the second ceramic electrolyte material include multiple ceramic electrolyte materials, it can be that one of them is different or that multiple of them are different.

[0042] As is understandable, expanded polytetrafluoroethylene (ePTFE) is a porous material made from polytetrafluoroethylene (PTFE) through special stretching and other processes. Its structural characteristics include a columnar structure of PTFE connecting PTFE fibers arranged in various directions, balancing the forces in all directions. This unique microporous and ultra-microstructure gives it properties such as flexibility, suppleness, and resistance to wear. ePTFE has high tensile strength, capable of withstanding significant tensile forces without breaking during stretching. It also possesses excellent flexibility, allowing it to bend over a wide range without cracking or damage. Furthermore, ePTFE exhibits strong tear resistance, with high tear strength, making it resistant to tearing even when punctured or pulled by sharp objects, thus improving the material's durability and reliability.

[0043] It is understandable that the pores of the porous substrate layer are also filled with a first ceramic electrolyte material and a second ceramic electrolyte material.

[0044] In some embodiments, the porous substrate layer is an expanded polytetrafluoroethylene (ePTFE) membrane.

[0045] In some embodiments, the thickness of the porous substrate layer is 2 μm to 18 μm.

[0046] The use of expanded polytetrafluoroethylene in this application allows for a smaller thickness of the porous substrate layer, which is beneficial for reducing the internal resistance of the battery. Optionally, the thickness of the porous substrate layer is 2μm, 4μm, 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, or 18μm, or the thickness of the porous substrate layer can be within any two of the above-mentioned thicknesses.

[0047] In some embodiments, the thickness of the solid electrolyte membrane is 8 μm to 30 μm.

[0048] The thinner thickness of the solid electrolyte membrane is beneficial for reducing the internal resistance of the battery. Optionally, the thickness of the solid electrolyte membrane is 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm or 30μm, or the thickness of the solid electrolyte membrane can be within any two of the above thicknesses.

[0049] In some embodiments, the pore size of the porous substrate layer is 0.3 μm to 8 μm.

[0050] Optionally, the pore size of the porous substrate layer is 0.3μm, 0.5μm, 0.8μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm or 8μm, or the pore size of the porous substrate layer can be within any two of the above pore size ranges.

[0051] In some embodiments, the porosity of the porous substrate layer is 60% to 85%.

[0052] Optionally, the porosity of the porous substrate layer is 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, or 85%, or the porosity of the porous substrate layer may be within the range of any two of the above porosities.

[0053] In some embodiments, the material of the first ceramic layer further includes a first oxide additive.

[0054] In some embodiments, the material of the second ceramic layer also includes a second oxide additive.

[0055] In some embodiments, the first oxide additive includes at least one of silicon dioxide and aluminum oxide.

[0056] In some embodiments, the second oxide additive includes at least one of silicon dioxide and aluminum oxide.

[0057] In some embodiments, the material of the first ceramic layer also includes a polymer material.

[0058] It is understandable that the material of the first ceramic layer also includes polymer materials, meaning that the material of the first ceramic layer is a ceramic polymer composite electrolyte material.

[0059] In some embodiments, the material of the second ceramic layer also includes a polymer material.

[0060] It is understandable that the material of the second ceramic layer also includes polymer materials, meaning that the material of the second ceramic layer is a ceramic polymer composite electrolyte material.

[0061] In some embodiments, the filler material also includes a polymer material.

[0062] It is understandable that the filler material also includes polymer materials, which refers to organic polymer composite electrolyte materials.

[0063] In some embodiments, the polymer material includes at least one of poly(vinylidene fluoride-hexafluoropropylene), polyacrylonitrile, and polyacrylic acid.

[0064] In some embodiments, the initial thermal runaway temperature of the solid electrolyte membrane is greater than or equal to 250°C.

[0065] In some embodiments, the electrochemical stability window of the solid electrolyte membrane is greater than or equal to 4.6V.

[0066] In some embodiments, the ionic conductivity of the solid electrolyte membrane is 1×10⁻⁶. -4 Scm -1 .

[0067] This application provides a method for preparing a solid electrolyte membrane, comprising the following steps:

[0068] A porous substrate layer is provided, wherein the material of the porous substrate layer includes expanded polytetrafluoroethylene;

[0069] A first ceramic layer and a second ceramic layer are respectively prepared on two opposing surfaces of a porous substrate layer. The material of the first ceramic layer includes a first ceramic electrolyte material, and the material of the second ceramic layer includes a second ceramic electrolyte material. The first ceramic electrolyte material and the second ceramic electrolyte material include Li. 1.5 Al 0.5 Ti 1.5 (PO4)3, Li7La3Zr2O 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 6.75 La3Zr 1.75 Ta 0.25 O 12 And Li 1.5 Al 0.5 Ge 1.5 At least one of (PO4)3, and the first ceramic electrolyte material and the second ceramic electrolyte material are different;

[0070] A filler material is filled into the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer. The filler material includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0071] In some embodiments, preparing a first ceramic layer and a second ceramic layer on two opposing surfaces of a porous substrate layer includes the following steps:

[0072] A first slurry comprising a first ceramic electrolyte material is coated onto the surface of a porous substrate layer, and the porous substrate layer is subjected to a first ultrasonic treatment and a first drying treatment in sequence to prepare a first ceramic layer.

[0073] A second slurry comprising a second ceramic electrolyte material is coated onto the surface of a porous substrate layer, and the porous substrate layer is subjected to a second ultrasonic treatment and a second drying treatment in sequence to prepare a second ceramic layer.

[0074] A third solution containing a filling material is coated on the surfaces of the first ceramic layer and the second ceramic layer. The porous substrate layer is then subjected to a third ultrasonic treatment and a third drying treatment in sequence, so that the filling material fills the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer.

[0075] In some embodiments, the duration of the first and / or second and / or third ultrasonic treatments is 5 min to 30 min.

[0076] Optionally, the duration of the first and / or second and / or third ultrasound treatments is 5 min, 10 min, 15 min, 20 min, 25 min, or 30 min, or the duration of the first and / or second and / or third ultrasound treatments may be within any two of the above-mentioned durations.

[0077] In some embodiments, the temperature of the first ultrasonic treatment and / or the second ultrasonic treatment and / or the third ultrasonic treatment is 0°C to 50°C.

[0078] Optionally, the temperature of the first ultrasonic treatment and / or the second ultrasonic treatment and / or the third ultrasonic treatment is 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C or 50°C, or the temperature of the first ultrasonic treatment and / or the second ultrasonic treatment and / or the third ultrasonic treatment may also be within the range of any two of the above temperatures.

[0079] In some embodiments, the temperature of the first drying process and / or the second drying process and / or the third drying process is 25°C to 140°C.

[0080] Optionally, the temperature of the first drying treatment and / or the second drying treatment and / or the third drying treatment is 25°C, 30°C, 40°C, 50°C, 60°C, 80°C, 100°C, 120°C or 140°C, or the temperature of the first drying treatment and / or the second drying treatment and / or the third drying treatment may also be within the range of any two of the above temperatures.

[0081] In some embodiments, the time for the first drying treatment and / or the second drying treatment and / or the third drying treatment is 0.5h to 24h.

[0082] Optionally, the time for the first drying treatment and / or the second drying treatment and / or the third drying treatment is 0.5h, 1h, 2h, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 22h or 24h, or the time for the first drying treatment and / or the second drying treatment and / or the third drying treatment may also be within the range between any two of the above times.

[0083] In some embodiments, after filling the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer with the filler material, the following steps are further included:

[0084] The solid electrolyte membrane is subjected to hot pressing treatment.

[0085] In some embodiments, the hot pressing temperature is 60°C to 120°C.

[0086] Optionally, the hot pressing temperature is 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, or the hot pressing temperature may be within any two of the above temperatures.

[0087] In some embodiments, the pressure of the hot pressing process is 2 MPa to 10 MPa.

[0088] Optionally, the pressure of the hot pressing treatment is 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa or 10MPa, or the pressure of the hot pressing treatment can be within the range of any two of the above pressures.

[0089] This application provides a solid-state battery, including a solid electrolyte membrane according to any one of the above claims or a solid electrolyte membrane prepared by any one of the above claims' preparation methods.

[0090] In some embodiments, the solid-state battery further includes a positive electrode and a negative electrode. The conductivity of the first ceramic electrolyte material is lower than that of the second ceramic electrolyte material. The first ceramic layer is in contact with the negative electrode, and the second ceramic layer is in contact with the positive electrode.

[0091] The following are specific embodiments.

[0092] Example 1

[0093] Preparation method of solid electrolyte membrane:

[0094] (1) Lay out a 3μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0095] (2) Weigh 0.1g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and 2.0g of Li 1.5 Al 0.5 Ti 1.5 (PO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry I;

[0096] (3) Weigh 0.1g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and 2.0g of Li7La3Zr2O 12 (LLZO) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry II;

[0097] (4) Weigh 1.0 g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and 1.5 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) into 8 mL of ethyl acetate solvent, seal and stir at room temperature for 12 h to obtain transparent viscous liquid III;

[0098] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0099] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0100] (7) After drying, cut the film and heat press it flat.

[0101] Reference Figures 1-5 As shown, Figure 1 Please see the scanning electron microscope image of the ePTFE membrane in Example 1. Figure 2 This is a cross-sectional view of the solid electrolyte membrane prepared in Example 1. Figure 3 The thermogravimetric analysis (TGA) of the solid electrolyte membrane prepared in Example 1 is shown below. Figure 4 This is a diagram showing the electrochemical stability window of the solid electrolyte membrane prepared in Example 1. Figure 5 The diagram shows the discharge specific capacity of the LiFePO4 / / Li battery corresponding to the solid electrolyte membrane prepared in Example 1 under charge and discharge conditions of 0.1C, 0.2C, 0.5C and 1C.

[0102] Example 2

[0103] (1) Lay out a 5μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0104] (2) Weigh 0.1g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and 2.0g of Li 1.5 Al 0.5 Ti 1.5(PO4)3 (LATP) and 0.1g Al2O3 were dissolved in 8mL of ethyl acetate, sealed, and stirred at room temperature for 12h to obtain a uniformly dispersed milky white slurry I;

[0105] (3) Weigh 0.1g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and 2.0g of Li7La3Zr2O 12 (LLZO) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry II;

[0106] (4) Weigh 1.0 g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and 1.5 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) into 8 mL of ethyl acetate solvent, seal and stir at room temperature for 12 h to obtain transparent viscous liquid III;

[0107] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0108] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0109] (7) After drying, cut the film and heat press it flat.

[0110] Example 3

[0111] (1) Lay out an 8μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0112] (2) Weigh out 0.1g of polyacrylonitrile (PAN) and 2.0g of Li 1.5 Al 0.5 Ti 1.5 (PO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry I;

[0113] (3) Weigh out 0.1g of polyacrylonitrile (PAN) and 2.0g of Li7La3Zr2O 12 (LLZO) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry II;

[0114] (4) Weigh 1.0 g of polyacrylonitrile (PAN) and 1.5 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into 8 mL of ethyl acetate solvent, seal and stir at room temperature for 12 h to obtain transparent viscous liquid III;

[0115] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0116] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0117] (7) After drying, cut the film and heat press it flat.

[0118] Example 4

[0119] (1) Lay out an 8μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0120] (2) Weigh out 0.1g of polyacrylonitrile (PAN) and 2.0g of Li 1.5 Al 0.5 Ti 1.5 (PO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry I;

[0121] (3) Weigh out 0.1g of polyacrylonitrile (PAN) and 2.0g of Li 6.4 La3Zr 1.4 Ta 0.6 O 12 0.1 g SiO2 was dissolved in 8 mL of ethyl acetate solvent, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry II;

[0122] (4) Weigh 1.0 g of polyacrylonitrile (PAN) and 1.5 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into 8 mL of ethyl acetate solvent, seal and stir at room temperature for 12 h to obtain transparent viscous liquid III;

[0123] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0124] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0125] (7) After drying, cut the film and heat press it flat.

[0126] Example 5

[0127] (1) Lay out a 15μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0128] (2) Weigh out 0.1g PAA and 2.0g Li 1.5 Al 0.5 Ti 1.5 (PO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry I;

[0129] (3) Weigh 0.1g PAA and 2.0g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Dissolved in 8 mL of ethyl acetate, sealed and stirred at room temperature for 12 h, a uniformly dispersed milky white slurry II was obtained;

[0130] (4) Weigh 1.0g PAA and 1.5g lithium bis(trifluoromethanesulfonyl)imide (LiFSI) into 8mL ethyl acetate solvent, seal and stir at room temperature for 12h to obtain transparent viscous liquid III;

[0131] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0132] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0133] (7) After drying, cut the film and heat press it flat.

[0134] Example 6

[0135] (1) Lay out a 15μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0136] (2) Weigh 0.1g PVDF-HFP and 2.0g Li 1.5 Al0.5 Ti 1.5 Lithium aluminum germanium phosphate (LiPO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain lithium germanium aluminum phosphate (LiPO4)3 (LATP). 1.5 Al 0.5 Ge 1.5 (PO4)3 (LAGP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry II;

[0137] (4) Weigh 1.0g PVDF-HFP and 1.5g lithium bis(trifluoromethanesulfonyl)imide (LiFSI) into 8mL ethyl acetate solvent, seal and stir at room temperature for 12h to obtain transparent viscous liquid III;

[0138] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0139] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0140] (7) After drying, cut the film and heat press it flat.

[0141] Example 7

[0142] (1) Lay out a 15μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0143] (2) Weigh 0.1g PVDF-HFP and 2.0g Li 1.5 Al 0.5 Ti 1.5 (PO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry I;

[0144] (3) Weigh 0.1g PVDF-HFP and 2.0g Li 1.5 Al 0.5 Ge 1.5 (PO4)3 (LAGP) and 0.1g Al2O3 were dissolved in 8mL of ethyl acetate, sealed, and stirred at room temperature for 12h to obtain a uniformly dispersed milky white slurry II;

[0145] (4) Weigh 1.0g PVDF-HFP and 1.5g lithium bis(trifluoromethanesulfonyl)imide (LiFSI) into 8mL ethyl acetate solvent, seal and stir at room temperature for 12h to obtain transparent viscous liquid III;

[0146] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0147] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0148] (7) After drying, cut the film and heat press it flat.

[0149] Example 8

[0150] (1) Lay out an 18μm thick ePTFE membrane and fix it on a frame to ensure that the membrane is taut. Soak it in ethanol and sonicate it for 30 minutes, then dry it.

[0151] (2) Weigh 0.1g PVDF-HFP and 2.0g Li 1.5 Al 0.5 Ti 1.5 (PO4)3 (LATP) was dissolved in 8 mL of ethyl acetate, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry I;

[0152] (3) Weigh 0.1g PVDF-HFP and 2.0g Li 1.5 Al 0.5 Ge 1.5 (PO4)3 (LAGP) and 0.1 g SiO2 were dissolved in 8 mL of ethyl acetate solvent, sealed, and stirred at room temperature for 12 h to obtain a uniformly dispersed milky white slurry II;

[0153] (4) Weigh 1.0g PVDF-HFP and 1.5g lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into 8mL ethyl acetate solvent, seal and stir at room temperature for 12h to obtain transparent viscous liquid III;

[0154] (5) Spray slurry I evenly onto one side of the fixed ePTFE, sonicate for 5 minutes, then spray slurry II evenly onto the other side of the ePTFE, sonicate for 5 minutes, then transfer to an 80℃ oven and vacuum dry for 24 hours.

[0155] (6) After drying, the viscous liquid III is evenly sprayed onto both sides of the membrane prepared in step (5), ultrasonicated for 5 min, and then vacuum dried for 24 h.

[0156] (7) After drying, cut the film and heat press it flat.

[0157] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0158] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A solid electrolyte membrane, characterized in that, The system includes a main membrane and a filling material. The main membrane comprises a porous substrate layer, a first ceramic layer, and a second ceramic layer, wherein the first ceramic layer and the second ceramic layer are respectively disposed on two opposite surfaces of the porous substrate layer. The porous substrate layer is made of expanded polytetrafluoroethylene (ePTFE). The first ceramic layer is made of a first ceramic electrolyte material, and the second ceramic layer is made of a second ceramic electrolyte material. Both the first and second ceramic electrolyte materials independently comprise Li. 1.5 Al 0.5 Ti 1.5 (PO4)3, Li7La3Zr2O 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 6.75 La3Zr 1.75 Ta 0.25 O 12 And Li 1.5 Al 0.5 Ge 1.5 The material comprises at least one of (PO4)3, and the first ceramic electrolyte material and the second ceramic electrolyte material are different; the pores of the porous substrate layer, the first ceramic layer and the second ceramic layer are all filled with the filling material, and the filling material includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

2. The solid electrolyte membrane according to claim 1, characterized in that, The thickness of the porous substrate layer is 2μm~18μm; and / or, The pore size of the porous substrate layer is 0.3 μm to 8 μm; and / or, The porosity of the porous substrate layer is 60%~85%.

3. The solid electrolyte membrane according to any one of claims 1 to 2, characterized in that, The material of the first ceramic layer further includes a first oxide additive; and / or, The material of the second ceramic layer also includes a second oxide additive.

4. The solid electrolyte membrane according to claim 3, characterized in that, The first oxide additive includes at least one of silicon dioxide and aluminum oxide; and / or, The second oxide additive includes at least one of silicon dioxide and aluminum oxide.

5. The solid electrolyte membrane according to any one of claims 1 to 2, 4, characterized in that, The material of the first ceramic layer and / or the material of the second ceramic layer and / or the filler material further includes a polymer material.

6. The solid electrolyte membrane according to claim 5, characterized in that, The polymer material includes at least one of poly(vinylidene fluoride-hexafluoropropylene), polyacrylonitrile, and polyacrylic acid.

7. A method for preparing a solid electrolyte membrane, characterized in that, The steps include the following: A porous substrate layer is provided, wherein the material of the porous substrate layer includes expanded polytetrafluoroethylene; A first ceramic layer and a second ceramic layer are respectively prepared on two opposing surfaces of the porous substrate layer. The material of the first ceramic layer includes a first ceramic electrolyte material, and the material of the second ceramic layer includes a second ceramic electrolyte material. The first ceramic electrolyte material and the second ceramic electrolyte material include Li. 1.5 Al 0.5 Ti 1.5 (PO4)3, Li7La3Zr2O 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 6.75 La3Zr 1.75 Ta 0.25 O 12 And Li 1.5 Al 0.5 Ge 1.5 At least one of (PO4)3, and the first ceramic electrolyte material and the second ceramic electrolyte material are different; A filling material is filled into the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer, wherein the filling material includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide.

8. The method for preparing a solid electrolyte membrane according to claim 7, characterized in that, After filling the pores of the porous substrate layer, the first ceramic layer, and the second ceramic layer with the filler material, the following steps are also included: The solid electrolyte membrane is subjected to hot pressing treatment.

9. The method for preparing a solid electrolyte membrane according to claim 8, characterized in that, The hot pressing temperature is 60℃~120℃; and / or; The pressure of the hot pressing process is 2MPa~10MPa.

10. A solid-state battery, characterized in that, Solid electrolyte membranes include those prepared by the method of preparing solid electrolyte membranes according to any one of claims 1 to 6 or any one of claims 7 to 9.

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