Solid-state electrolyte membrane and solid-state battery

Abstract

This invention provides a solid-state electrolyte membrane and a solid-state battery, belonging to the field of secondary battery technology. The solid-state electrolyte membrane of this invention includes a first membrane layer, a second membrane layer, and a third membrane layer. The first membrane layer includes a halide electrolyte; the second membrane layer is disposed on the first membrane layer and includes a sulfide electrolyte; the third membrane layer is disposed on the second membrane layer and includes fluorinated polyimide and a covalent organic framework material. This solid-state electrolyte membrane, by optimizing the material composition of the three membrane layers, achieves high ionic conductivity and electrode compatibility while improving the thermodynamic matching and kinetic synergy between the membrane layers, thereby significantly reducing interlayer interface impedance and improving both the overall flexibility and long-cycle stability of the membrane. This provides key material support for the practical application of high-energy-density, high-safety solid-state lithium batteries.

Description

Technical Field

[0001] This invention relates to the field of secondary battery technology, and more particularly to a solid electrolyte membrane and a solid battery. Background Technology

[0002] With the increasing demand for high-energy-density and high-safety batteries from electric vehicles, wearable devices, and large-scale energy storage, traditional liquid lithium-ion batteries are becoming unsustainable due to risks such as flammability, leakage, and thermal runaway. As a core direction of next-generation energy storage technology, all-solid-state batteries use non-flammable solid electrolytes instead of organic liquid electrolytes, which not only significantly improves safety but also provides a compatible lithium metal anode, making it possible for solid-state batteries to achieve energy densities exceeding 500Wh / kg.

[0003] Current mainstream solid-state electrolytes (such as polymer solid-state electrolytes, sulfide solid-state electrolytes, and halide solid-state electrolytes) each have significant shortcomings in their respective systems. Single-system solid-state electrolyte materials have prominent limitations in constructing solid-state electrolyte membranes, making it difficult to simultaneously achieve high ionic conductivity, a wide electrochemical window, good mechanical structural stability, and electrochemical stability. To achieve multiple performance characteristics, the industry has often attempted to construct multilayer or gradient-component solid-state electrolyte membranes to compensate for the deficiencies of single materials. However, currently designed multilayer solid-state electrolyte membrane structures generally suffer from high interlayer interfacial impedance and weak bonding, and it is difficult to form a stable interfacial phase at the membrane-electrode interface. This leads to a continuous deterioration of the interfacial stability of the solid-state electrolyte membrane during cycling, affecting the rate capability and cycle performance of the battery.

[0004] Therefore, it is necessary to design a solid electrolyte membrane and a solid battery to improve the above problems. Summary of the Invention

[0005] This invention provides a solid electrolyte membrane and a solid battery to address the problem that existing solid electrolyte membrane structures cannot simultaneously achieve high ionic conductivity, wide electrochemical window, good electrode interface compatibility, structural stability, and electrochemical stability.

[0006] In a first aspect, the present invention provides a solid electrolyte membrane comprising a first membrane layer, a second membrane layer, and a third membrane layer. The first membrane layer comprises a halide electrolyte; the second membrane layer is disposed on the first membrane layer and comprises a sulfide electrolyte, wherein the sulfide electrolyte comprises Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δWherein, 0≤x≤1.5, 0≤y≤1.5, y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A includes at least one of Na and K; M1 includes at least one of Ge, Sn, Si, P, As, and B; M2 includes at least one of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 includes at least one of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; X includes at least one of O, Se, and Te; the third film layer is disposed on the second film layer, and the third film layer includes fluorinated polyimide and a covalent organic framework material.

[0007] In one example of the present invention, the thickness of the first film layer is 1~100 μm.

[0008] In one example of the present invention, the thickness of the second film layer is 1~200 μm.

[0009] In one example of the present invention, the thickness of the third film layer is 1~100 μm.

[0010] In one example of the present invention, the thickness of the first film layer is 10~30 μm.

[0011] In one example of the present invention, the thickness of the second film layer is 30~60 μm.

[0012] In one example of the present invention, the thickness of the third film layer is 10~30 μm.

[0013] In one example of the present invention, the covalent organic framework material in the third film layer has a mass content of 1 to 50 wt%.

[0014] In one example of the present invention, the covalent organic framework material in the third film layer has a mass content of 10~30wt%.

[0015] In one example of the present invention, the covalent organic framework material has nanopores.

[0016] In one example of the present invention, the pore size of the nanopore is 1~3nm.

[0017] In one example of the present invention, the specific surface area of ​​the covalent organic framework material is greater than 500 μm. 2 / g.

[0018] In one example of the present invention, when the covalent organic framework material is in the form of particles, the particle size of the particulate covalent organic framework material is 50 nm to 5 μm.

[0019] In one example of the present invention, when the covalent organic framework material is in sheet form, the sheet diameter of the covalent organic framework material is 50 nm to 5 μm, and the thickness of the covalent organic framework material is 2 to 100 nm.

[0020] In one example of the present invention, the framework of the covalent organic framework material contains heteroatoms, which include at least one of nitrogen, oxygen, fluorine or sulfur.

[0021] In one example of the present invention, the outer diameter of the covalent organic framework material is 50 nm to 5 μm, and the thickness of the covalent organic framework material is 2 to 100 nm.

[0022] In one example of the present invention, the covalent organic framework material is formed by covalently connecting building units, which are connected by linking groups, including at least one of imine bonds, hydrazone bonds, β-ketoenamine bonds, borate ester bonds, triazine rings, benzoxazole, benzothiazole, imide bonds, or urea bonds.

[0023] In one example of the present invention, the halide electrolyte includes Li3YCl6, Li3YBr6, Li3InCl6, Li3ScCl6, Li2ZrCl6, Li2HfCl6, Li3LuCl6, Li3ErCl6, and Li3Y (1 z) M z At least one of Cl6, wherein M includes at least one of rare earth elements and transition metal elements, and 0≤z≤0.5.

[0024] In one example of the present invention, the third film layer further includes a lithium salt, wherein the molar content of the lithium salt in the third film layer is 5 to 30 mol%, and the lithium salt includes at least one of LiTFSI, LiFSI, LiPF6 or LiBOB.

[0025] In a second aspect, the present invention also provides a method for preparing a solid electrolyte membrane, the method comprising: The halide electrolyte is formulated to form the first membrane layer; A sulfide electrolyte raw material is prepared by mixing Li source, A source, M1 source, M2 source, M3 source, S source, and X source in a stoichiometric ratio; the sulfide electrolyte raw material is then sintered to produce a sulfide electrolyte. The sulfide electrolyte is formulated to form a second film layer; A mixture is prepared by mixing dianhydride monomer, diamine monomer, and covalent organic framework material in a solvent at a predetermined mass ratio, and inducing the polymerization of the dianhydride monomer and the diamine monomer to form polyamic acid. The mixture is cast into a membrane and subjected to thermal imidization to form a third membrane layer. The first membrane layer, the second membrane layer, and the third membrane layer are stacked and pressed together to form a solid electrolyte membrane.

[0026] In one example of the present invention, the sintering treatment of the sulfide electrolyte raw material to produce the sulfide electrolyte includes: sintering the sulfide electrolyte raw material at a preset sintering temperature for 1 to 12 hours to obtain the sulfide electrolyte, wherein the sintering temperature is 150°C to 500°C.

[0027] In one example of the present invention, the thermal imidization treatment of the membrane includes: heating the cast membrane to a preset temperature in an inert atmosphere or vacuum environment; wherein the preset temperature is 150~220℃, and the heating time for the thermal imidization treatment is 2~6 hours.

[0028] In one example of the present invention, the preparation of the halide electrolyte to form the first film layer includes: mixing the halide electrolyte and the binder in a solvent at a mass ratio of (95~99.5):(0.5~5) to prepare a first slurry; coating the first slurry onto a substrate, and heating and drying the first slurry coated on the substrate to obtain the first film layer.

[0029] In one example of the present invention, the step of preparing the sulfide electrolyte to form the second film layer includes: mixing the sulfide electrolyte and the binder in a solvent at a mass ratio of (95~99.5):(0.5~5) to prepare a second slurry; coating the second slurry onto a substrate; and heating and drying the second slurry coated on the substrate to obtain the second film layer.

[0030] In a third aspect, the present invention also provides a solid-state battery comprising the solid electrolyte membrane described in any of the foregoing examples.

[0031] The solid electrolyte membrane provided by the present invention includes a first membrane layer, a second membrane layer and a third membrane layer arranged sequentially along the thickness direction. The first membrane layer includes a halide electrolyte, the second membrane layer includes a high-entropy sulfide electrolyte, and the third membrane layer includes fluorinated polyimide and a covalent organic framework material (COF).

[0032] This solid-state electrolyte membrane utilizes the high oxidation stability of halide electrolytes on the positive electrode side to enhance its electrochemical stability at high operating voltages, thereby achieving a wide electrochemical window performance. On the negative electrode side, a composite polymer electrolyte is introduced to improve the overall membrane flexibility, and a continuous Li3 structure is constructed in the third layer using ordered nanopores of COF material. +The transport pathway promotes the formation of a stable interface layer rich in LiF and Li3N between ions and active heteroatoms in the fluorinated polyimide backbone during cyclic ion conduction, improving the interfacial compatibility between the solid electrolyte membrane and the negative electrode, and significantly improving the low ionic conductivity of polymer electrolytes. A high-entropy sulfide electrolyte is introduced into the intermediate second membrane layer of the solid electrolyte membrane. Based on the synergistic effect of multiple principal elements in the high-entropy sulfide electrolyte, a smooth ion transport gradient is formed between the first and third membrane layers, and a stable ion conduction interface layer is constructed at the contact interface between the second membrane layer and the first and third membrane layers. This significantly improves the structural and interfacial thermodynamic stability while maintaining the high ionic conductivity of the solid electrolyte membrane.

[0033] In summary, the solid electrolyte membrane provided in this application optimizes the composition of the three membrane layers to achieve high ionic conductivity and electrode compatibility while improving the thermodynamic matching and kinetic synergy between the layers. This significantly reduces the interlayer impedance and improves the overall flexibility and long-cycle stability of the membrane, providing key material support for the practical application of high-energy-density and high-safety solid-state lithium batteries. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other embodiments based on these drawings without inventive effort.

[0035] In the attached diagram: Figure 1 This is a schematic diagram of the structure of a solid electrolyte membrane in one embodiment of the present invention; Figure 2 This is a schematic flowchart of a solid electrolyte membrane preparation method according to an embodiment of the present invention.

[0036] The attached figures are labeled as follows: 10. First membrane layer; 20. Second membrane layer; 30. Third membrane layer. Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0038] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as part of the scope of the invention.

[0039] In this specification, the average particle size (D50) can be defined as the particle size at which the cumulative percentage of particle size distribution in a volume-based particle group reaches 50%, i.e., half of the particles in the sample have a particle size less than or equal to this value, and the other half have a particle size greater than or equal to this value. The average particle size (D50) can be measured, for example, by laser diffraction. Laser diffraction can typically measure particle sizes from the submicron range to several millimeters, thus providing highly reproducible and high-resolution results.

[0040] Currently, each mainstream solid-state electrolyte system has significant shortcomings. For example, polymer electrolytes have good flexibility but suffer from low ionic conductivity and poor oxidation resistance at high potentials; sulfide electrolytes have high ionic conductivity but suffer from poor electrochemical stability and easy decomposition to release H2S; halide electrolytes, while having good oxidation resistance, are too hard and brittle and have poor chemical compatibility with lithium metal anodes. The limitations of single-system solid-state electrolyte materials in constructing solid-state electrolyte membranes are prominent due to their respective performance defects. No single type of solid-state electrolyte material can simultaneously satisfy high ionic conductivity (>10). -3 S / cm), wide electrochemical window (>4.5 V vs. Li) + The system requires a combination of factors, including good electrochemical stability and mechanical flexibility.

[0041] Research has revealed that while the industry has attempted to construct multilayer or gradient-component solid electrolyte membranes to compensate for the shortcomings of single materials, most existing multilayer solid electrolyte membrane structures rely solely on the physical stacking of material layers. This often results in delamination issues due to interlayer thermal expansion and modulus mismatch, and a lack of effective heterogeneous interlayer interface control mechanisms. Consequently, they fail to actively construct a stable interfacial phase with high lithium-ion conductivity and low electronic conductivity at the electrode / electrolyte interface. This leads to high interfacial impedance and weak bonding in these solid electrolyte membranes, affecting the rate and cycle performance of the battery.

[0042] To address the aforementioned issues, this application provides a solid electrolyte membrane. This membrane introduces a halide electrolyte in the first layer on the positive electrode side to accommodate the high-potential positive electrode, thereby broadening the electrochemical window of the solid electrolyte membrane. In the third layer on the negative electrode side, a polymeric electrolyte composed of COF material and fluorinated polyimide is introduced to enhance the overall flexibility of the solid electrolyte membrane and achieve stable compatibility with the negative electrode interface while ensuring that the ionic conductivity of the solid electrolyte membrane does not excessively decrease. In the second layer, the synergistic effect of multiple principal elements in the high-entropy sulfide electrolyte introduces lattice distortion and hysteresis diffusion effects to provide an intermediate layer with suitable ionic conductivity and flexibility, thereby forming a smooth ion transport gradient and an interface layer with ion transport properties between the first and third layers. By introducing a second film layer in the middle, the first and third film layers can be stably bonded together through the intermediate film layer with appropriate plastic deformation capability. This effectively avoids the high interfacial impedance caused by chemical incompatibility at heterogeneous interfaces, alleviates lithium ion accumulation and interfacial polarization caused by energy level abrupt changes in traditional heterogeneous interfaces, and achieves effective integration of halide electrolytes and polymer electrolytes. Thus, while maintaining the high ionic conductivity of the membrane, the structural and interfacial dynamic stability of the solid electrolyte membrane is significantly improved.

[0043] like Figure 1 As shown, in a first aspect, this application provides a solid electrolyte membrane, which includes a first membrane layer 10, a second membrane layer 20 and a third membrane layer 30, wherein the second membrane layer 20 is disposed on the first membrane layer 10 and the third membrane layer 30 is disposed on the second membrane layer 20.

[0044] In the solid electrolyte membrane, the first membrane layer 10 is configured to contact the positive electrode. The first membrane layer 10 includes a halide electrolyte, which has high oxidation stability and can maintain the electrochemical stability of the contact interface between the first membrane layer 10 and the positive electrode at high voltages above 4.5V, thereby improving the oxidation tolerance of the solid electrolyte membrane to the positive electrode at high voltages above 4.5V and broadening the electrochemical window of the solid electrolyte membrane.

[0045] The third film layer 30 is configured to contact the negative electrode. The third film layer 30 comprises fluorinated polyimide and a covalent organic framework (COF) material. The COF material is dispersed and mixed into the fluorinated polyimide, and the COF material and fluorinated polyimide are composite to form the polymer electrolyte in the third film layer 30. The fluorinated polyimide possesses suitable hardness and good flexibility. When in contact with the negative electrode (especially metallic lithium), it enables the third film layer 30 to resist the puncture effect of lithium dendrite growth and improves the overall flexibility of the solid electrolyte membrane to accommodate volume changes during charging and discharging of the negative electrode, preventing crack formation at the contact interface. Simultaneously, the fluorinated groups in the fluorinated polyimide induce the formation of a stable interface layer rich in highly ion-conductive LiF and Li3N at the contact site with the negative electrode during charge-discharge cycling. This reduces the interfacial impedance between the solid electrolyte membrane and the negative electrode, inhibits side reactions between active lithium and the electrolyte, and limits the uncontrolled growth of lithium dendrites. Furthermore, COF materials are crystalline porous polymers formed by covalently linked building blocks. COF materials possess ordered nano-ion channels, and the COF materials dispersed between flexible fluorinated polyimides can construct continuous Li₂ in the third film layer 30. + The transport path promotes rapid and directional transport of lithium ions in the third film layer 30 during cycling and significantly inhibits the movement of anions, thereby improving the mobility of lithium ions in the third film layer 30 and improving the defect of low ionic conductivity of polymer electrolyte.

[0046] The second membrane layer 20 is located between the first membrane layer 10 and the third membrane layer 30. The second membrane layer 20 includes a sulfide electrolyte, which includes a sulfide electrolyte with the chemical formula Li. 4±x-y A y (M1 a M2 b M3 c S4 δ X δ At least one of the following materials. Wherein, 0≤x≤1.5, 0≤y≤1.5, y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A includes at least one of Na and K; M1 includes at least one of Ge, Sn, Si, P, As, and B; M2 includes at least one of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 includes at least one of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; X includes at least one of O, Se, and Te.

[0047] The introduction of multiple metal elements or combinations of metal and non-metal elements (M1, M2, and M3) into the sulfide electrolyte enables the formation of a high-entropy alloy framework. This high-entropy alloy framework introduces a highly disordered amorphous structure into the solid electrolyte material, providing richer ion migration channels for the sulfide electrolyte. This effectively lowers the activation energy barrier for ion migration and transport within the sulfide electrolyte, resulting in a room-temperature ionic conductivity of 10⁻⁶. -3 S / cm~10 - 2 The order of magnitude is in the S / cm range.

[0048] The sulfide electrolyte utilizes multi-key element doping to regulate the ion conduction properties of the material. The lithium chemical potential and ion migration activation energy of the sulfide electrolyte in this application are between those of the halide electrolyte in the first layer 10 and the polymer electrolyte in the third layer 30. The second layer 20, located in the middle, introduces the sulfide electrolyte, enabling a smooth ion transport gradient along the thickness direction within the solid electrolyte membrane. This effectively alleviates lithium-ion accumulation and interfacial polarization caused by energy level abrupt changes at heterogeneous interfaces in traditional multilayer solid electrolyte membranes, reduces the interfacial impedance between the three layers, and ultimately achieves efficient interlayer transport of lithium ions within the solid electrolyte membrane.

[0049] The sulfide electrolyte in the second film layer 20, through the synergistic effect of multiple key elements, can induce the formation of a LiF-rich interface layer with the COF material in the third film layer 30, and covalently or ionicly bond with the passivation layer on the surface of the halide electrolyte in the first film layer 10, thereby forming a stable lithium-ion transport channel between the first film layer 10 and the second film layer 20. Based on the highly ionicly conductive interface layer formed between the second film layer 20 and the first and third film layers 10 and 30, the high impedance caused by chemical incompatibility at heterogeneous interfaces in traditional multilayer solid electrolyte membranes can be avoided, improving the compatibility of multilayer heterogeneous interfaces in solid electrolyte membranes and increasing the ionic conductivity of the solid electrolyte membrane. Furthermore, the sulfide electrolyte, through the synergistic effect of multiple key elements, can introduce lattice distortion and hysteresis diffusion effects into the second film layer 20 to block the Cl- of the halide electrolyte in the first film layer 10. - or Br - The interdiffusion of residual functional groups of polymer electrolyte in the third membrane layer 30 during cycling improves the kinetic stability of the membrane while maintaining the high ionic conductivity of the solid electrolyte membrane.

[0050] Meanwhile, sulfide electrolytes utilize the introduction of elements M1, M2, and M3 to form bonds of varying strengths with elements S or X, creating a gradient bonding network structure where strong and weak bonds coexist. Among these, elements of class M1 (such as Ge and P) can form strong covalent bonds with elements S or X (e.g., [GeS4]). 4- [PS4] 3-The strong covalent bonds formed constitute a rigid network framework in the solid electrolyte, effectively improving the mechanical strength of the solid electrolyte material. The bonding strength between some M2 and M3 elements and S or X elements is relatively weak or more ionic. The weakly bonded regions occupied by M2 and M3 elements in the sulfide electrolyte can undergo local slippage or reconstruction under stress, playing a role in energy dissipation and preventing crack propagation. The gradient bonding network structure with both strong and weak bonds can improve the overall structural strength of the sulfide electrolyte material while also optimizing its flexibility. This effectively improves the high brittleness of glassy sulfide electrolytes, enhances their fracture toughness and fatigue resistance, and allows the sulfide electrolyte to adapt to hot pressing and electrode volume changes during cycling, thus maintaining its structural and performance stability.

[0051] The high ionic conductivity of solid-state electrolyte membranes typically relies on rigid halide electrolyte materials, while mechanical flexibility depends on polymer electrolyte materials. However, halide electrolytes are too brittle, and polymer electrolytes are too soft; direct composites of the two are prone to delamination or microcracks during processing or battery charge-discharge cycles. Sulfide electrolytes, with their unique lattice distortion structure and moderate mechanical flexibility, enable the second layer 20 in the solid-state electrolyte membrane to maintain sufficient rigidity to resist lithium dendrite growth and penetration, while also possessing a certain degree of plastic deformation capability to accommodate the bending deformation of flexible devices. The second layer 20, located in the middle, leverages its excellent mechanical compatibility to maintain tight interfacial contact in the three-layer structure of the solid-state electrolyte membrane under low stacking pressure (<5MPa), avoiding performance degradation due to interfacial debonding.

[0052] In summary, the solid-state electrolyte membrane of this application, based on an effective heterogeneous interlayer interface dynamics regulation mechanism, enables the first membrane layer 10, the second membrane layer 20, and the third membrane layer 30 to work synergistically. Specifically, the halide electrolyte in the first membrane layer 10 supports the compatibility of the solid-state electrolyte membrane with the high-voltage electrode; the sulfide electrolyte in the second membrane layer 20 helps the solid-state electrolyte membrane organically combine the first membrane layer 10 and the third membrane layer 30, achieving high ionic conductivity, low interfacial impedance, and good structural stability; and the polymer electrolyte in the third membrane layer 30 ensures the structural stability of the solid-state electrolyte membrane at the negative electrode interface. Through the synergistic effect of the three membrane layers, the solid-state electrolyte membrane of this application can support high areal capacity (≥4 mAh / cm³) in solid-state batteries. 2 The stable operation of the electrodes enables the solid-state battery to maintain more than 80% of its capacity after 300 cycles at a high voltage of 4.5V or above.

[0053] In some embodiments, the thickness of the first film layer 10 is any value in the range of 1 to 100 μm, for example, it can be 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm. Optionally, the thickness of the first film layer 10 can be any value in the range of 10 to 30 μm, for example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm.

[0054] In some embodiments, the thickness of the second film layer 20 is any value in the range of 1 to 200 μm, for example, it can be 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm. Optionally, the thickness of the second film layer 20 can be any value in the range of 30 to 60 μm, for example, it can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, or 60 μm.

[0055] In some embodiments, the thickness of the third film layer 30 is any value in the range of 1 to 100 μm, for example, it can be 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm. Optionally, the thickness of the third film layer 30 can be any value in the range of 10 to 30 μm, for example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm.

[0056] In some embodiments, the halide electrolyte includes Li3YCl6, Li3YBr6, Li3InCl6, Li3ScCl6, Li2ZrCl6, Li2HfCl6, Li3LuCl6, Li3ErCl6, and Li3Y. (1 z) M z At least one of Cl6. In Li3Y (1 z) M zIn Cl6, M includes at least one rare earth element or transition metal element, and 0 ≤ z ≤ 0.5. The halide electrolyte can be any of the materials listed above, such as Li3YCl6, Li3YBr6, Li3InCl6, Li3ScCl6, Li2ZrCl6, Li2HfCl6, Li3LuCl6, Li3ErCl6, or Li3Y (1 z) M z Cl6; the halide electrolyte can also be any two or more combinations of the materials listed above. For example, the halide electrolyte can be a combination of Li3YCl6 and Li3InCl6, or a combination of Li2ZrCl6 and Li2HfCl6, or a combination of Li3YBr6 and Li3ErCl6, or Li3ScCl6, Li3LuCl6 and Li3Y (1 z) M z Combinations of Cl6, or combinations of Li3YCl6, Li3InCl6, and Li2HfCl6, etc., are not listed here. When the halide electrolyte is a combination of two or more materials, the proportion of each material within the combination is not limited and can be mixed in any proportion. In other embodiments, the halide electrolyte may also be materials not listed above.

[0057] In some embodiments, the mass content of the covalent organic framework material in the third film layer 30 is any value in the range of 1 to 50 wt%, for example, the mass content of the covalent organic framework material can be 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0058] In one embodiment, the mass content of the covalent organic framework material in the third film layer 30 can be any value within the range of 10 to 30 wt%, for example, the mass content of the covalent organic framework material can be 10 wt%, 12 wt%, 14 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, or 30 wt%. Optionally, the mass content of the covalent organic framework material in the third film layer 30 can be any value within the range of 15 to 25 wt%, for example, the mass content of the covalent organic framework material can be 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, or 25 wt%.

[0059] In some embodiments, the covalent organic framework material is formed by covalently linking building units, which are connected by linking groups. The building units include at least one of amine monomers, aldehyde monomers, ketaldehyde monomers, acylhydrazine monomers, boric acid monomers, vicinal diol monomers, nitrile monomers, dianhydride monomers, and isocyanate monomers. The linking groups include at least one of imine bonds, hydrazone bonds, β-ketoenamine bonds, borate ester bonds, triazine rings, benzoxazoles, benzothiazoles, imine bonds, or urea bonds.

[0060] In some embodiments, the covalent organic framework material has a two-dimensional or three-dimensional periodic topology, and nanoporous structures are formed within the ring-shaped topology of the covalent organic framework material. In one embodiment, the pore size of the nanopores in the covalent organic framework material ranges from 1 to 3 nm, and the specific surface area of ​​the covalent organic framework material is greater than or equal to 500 m². 2 / g.

[0061] In some embodiments, the topological framework of the covalent organic framework material contains heteroatoms, including at least one of N, O, F, and S. When the nanopores of the covalent organic framework material facilitate lithium-ion migration, the heteroatoms on its framework can induce the formation of an interfacial protective layer containing LiF and / or Li3N upon contact with lithium metal.

[0062] It should be noted that the structural type of the covalent organic framework material is not limited, and the covalent organic framework material can be nanoparticles or nanosheets. In some embodiments, the particle size or sheet size of the covalent organic framework material is any value in the range of 50 nm to 5 μm, for example, 50 nm, 100 nm, 300 nm, 500 nm, 800 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm. The thickness of the sheet-like covalent organic framework material is any value in the range of 2 to 100 nm, for example, 2 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, or 100 nm.

[0063] In some embodiments, the third film layer 30 further includes a lithium salt, and the molar content of the lithium salt in the third film layer 30 is any value in the range of 5 to 30 mol%, for example, it can be 5 mol%, 8 mol%, 10 mol%, 13 mol%, 15 mol%, 18 mol%, 20 mol%, 23 mol%, 25 mol%, 28 mol%, or 30 mol%.

[0064] In some embodiments, the lithium salt in the third film layer 30 includes at least one of LiTFSI, LiFSI, LiPF6, or LiBOB. That is, the lithium salt can be any one of the materials listed above, such as LiTFSI, LiFSI, LiPF6, or LiBOB; the lithium salt can also be any combination of two or more of the materials listed above, for example, a combination of LiTFSI and LiFSI, or a combination of LiPF6 and LiBOB, or a combination of LiTFSI and LiPF6, or a combination of LiFSI, LiBOB, and LiTFSI, etc., etc., which will not be listed here. When the lithium salt is a combination of two or more materials, the proportion of each material within the combination is not limited, and they can be mixed in any proportion. In other embodiments, the lithium salt can also be a material not listed above.

[0065] In some embodiments, the ionic conductivity of the halide electrolyte in the first membrane layer 10 is 1 × 10⁻⁶. -3 ~1×10 - 2 The ionic conductivity of the sulfide electrolyte in the second membrane layer 20 is 1×10⁻⁶ S / cm. -3 ~2×10 -2 S / cm, the ionic conductivity of the polymer electrolyte in the third film layer 30 is 1×10⁻⁶. -5 ~1×10 -3 S / cm. The solid electrolyte membrane forms a smooth transition ion transport gradient along the thickness direction, which alleviates the lithium ion accumulation and interfacial polarization caused by energy level abrupt changes at heterogeneous interfaces in traditional multilayer solid electrolyte membranes.

[0066] In a second aspect, this application also provides a method for preparing a solid electrolyte membrane, such as... Figure 2 As shown, the preparation method includes the following steps: S1. The halide electrolyte is prepared to form the first membrane layer; S2. Mix the Li source, A source, M1 source, M2 source, M3 source, S source, and X source in a stoichiometric ratio to prepare a sulfide electrolyte raw material; sinter the sulfide electrolyte raw material to produce a sulfide electrolyte. S3. The sulfide electrolyte is prepared to form a second film layer; S4. The dianhydride monomer, diamine monomer, and covalent organic framework material are mixed in a solvent according to a preset mass ratio, and the dianhydride monomer and the diamine monomer are induced to polymerize to form polyamic acid, so as to prepare a mixture. S5. Cast the mixture into a membrane and subject the membrane to thermal imidization treatment to form a third membrane layer. S6. The first membrane layer, the second membrane layer and the third membrane layer are stacked and pressed together to form a solid electrolyte membrane.

[0067] In some embodiments, in step S1, the halide electrolyte and the binder are mixed in a solvent at a mass ratio of (95~99.5):(0.5~5) to prepare a first slurry; the first slurry is coated onto a substrate, and the first slurry coated onto the substrate is heated and dried (e.g., heated and dried at a temperature of 60°C~100°C for 6 to 24 hours) to obtain a first film layer.

[0068] In some embodiments, step S2 includes the following steps: S21, According to the chemical formula of solid electrolyte Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δ The Li source, A source, M1 source, M2 source, M3 source, S source, and X source are mixed evenly according to the stoichiometric ratio, and then added to a ball mill jar for ball milling to obtain a uniformly mixed sulfide electrolyte raw material.

[0069] During the ball milling process, the ball-to-material mass ratio is (1~100):1, for example, 1:1, 25:1, 50:1, 75:1 or 100:1; the ball milling speed is 50~1500 rpm, for example, 50 rpm, 100 rpm, 300 rpm, 500 rpm, 700 rpm, 1000 rpm, 1300 rpm or 1500 rpm; the ball milling time is 1~48 hours, for example, 1 hour, 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours or 48 hours.

[0070] S22. Sinter the sulfide electrolyte raw material at a preset sintering temperature for 1 to 12 hours, then cool the sintered product to room temperature at a cooling rate of 1 to 10°C / s to obtain the sulfide electrolyte. The sintering temperature for the sulfide electrolyte raw material can be any value within the range of 150°C to 500°C, for example, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, or 500°C. When the sintering temperature is within the above suitable range, both the density and glassy purity of the sintered sulfide electrolyte material can be considered. If the sintering temperature is too low, the resulting sulfide electrolyte material will have insufficient density, resulting in a large number of voids remaining in the solid electrolyte, leading to low ionic conductivity and high Young's modulus. If the sintering temperature is too high, crystallization will begin to occur in the sulfide electrolyte, reducing the glassy purity of the sulfide electrolyte, which in turn causes a sharp increase in Young's modulus and a significant decrease in ionic conductivity.

[0071] Furthermore, in step S2, the Li source can be selected from compounds containing the Li element or elemental Li. More specifically, the Li source can be selected from one or more of Li2S, Li2O, LiOH, Li2Se, Li2Te, and metallic Li.

[0072] The source A can be selected from compounds or elemental substances containing element A. Further, the source A can be selected from one or more of Na2S, K2S, Na2O, K2O, Na2Se, K2Se, metallic Na, and metallic K.

[0073] The M1 source can be selected from compounds containing the M1 element, such as one or more of sulfides, oxides, selenides, and tellurides containing the M1 element.

[0074] The M2 source can be selected from compounds containing the M2 element, such as one or more of sulfides, oxides, selenides, and tellurides containing the M2 element.

[0075] The M3 source can be selected from compounds containing the M3 element, such as one or more of sulfides, oxides, selenides, and tellurides containing the M3 element.

[0076] The S source is selected from compounds containing the element S. Further, the S source is selected from one or more of elemental S, Li2S, Na2S, sulfides of M1, sulfides of M2, and sulfides of M3.

[0077] The X source is selected from compounds containing the X element. Further, the X source is selected from one or more of the oxides, selenides, tellurides, and Se and Te corresponding to the M1, M2, and M3 elements.

[0078] In some embodiments, in step S3, the sulfide electrolyte and the binder are mixed in a solvent at a mass ratio of (95~99.5):(0.5~5) to prepare a second slurry; the second slurry is coated onto a substrate, and the second slurry coated onto the substrate is heated and dried (e.g., heated and dried at a temperature of 60°C~100°C for 6 to 24 hours) to obtain a second film layer.

[0079] In the above embodiments regarding steps S1 and S3, the binder used to prepare the slurry is selected from polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyurethane, polyvinyl alcohol (PVA), sodium alginate (Alg), and ethylene. propylene Diene monomers, styrene The slurry is prepared from at least one of the following: butadiene rubber, polyvinylidene fluoride (PVDF), fluororubber, β-cyclodextrin polymer (β-CDp), polypropylene emulsion (LA132), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy resin (PFA), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride-hexafluoropropylene copolymer, and polyvinylidene fluoride-trifluorochloroethylene copolymer. The solvent used to prepare the slurry is selected from at least one of the following: toluene, chlorobenzene, xylene, dimethyl carbonate, N-methylformamide, n-hexane, dimethyl glycol ether, dibutyl ether, ethanol, 1,2-ethylenediamine, 1,2-ethylenedithiol, acetonitrile, tetrahydrofuran, methanol, isopropyl ether, acetone, hexene, ethyl acetate, benzyl acetate, butyl butyrate, and diisobutyl ketone. The substrate used to prepare the first or third film layer is selected from one or more mixtures of PET, aluminum foil, steel foil, and copper foil.

[0080] In some embodiments, step S4 includes the following steps: S41. Disperse the covalent organic framework material in a polar aprotic solvent to obtain a dispersion.

[0081] In step S41, the polar aprotic solvent is selected from at least one of N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), or dimethyl sulfoxide (DMSO).

[0082] S42. The diamine monomer and dianhydride monomer are added dropwise to the dispersion in sequence, and the dianhydride monomer and diamine monomer are polymerized in the dispersion to form polyamic acid under a protective atmosphere at room temperature to obtain a mixture.

[0083] In some embodiments, the dianhydride monomer may be a fluorinated aromatic dianhydride monomer, and the diamine monomer may be an aromatic diamine monomer.

[0084] In addition, in some embodiments, step S42 further includes adding a lithium salt in a preset mass ratio to the mixture, wherein the lithium salt includes at least one of LiTFSI, LiFSI, LiPF6 or LiBOB.

[0085] In some embodiments, in step S5, the mixture is cast into a film, and the cast film is subjected to gradient thermal imidization treatment, so that the polyamic acid in the film forms fluorinated polyimide to form a third film layer. The thermal imidization treatment includes: heating the cast film to a preset temperature by gradient heating; specifically, in a vacuum or inert atmosphere, the cast wet film is heated from room temperature to 60~90°C and held at that temperature for 30~60 minutes; then heated to 100~140°C and held at that temperature for 30~60 minutes; finally, the temperature is raised to a preset temperature of 150~220°C and held at that temperature for 60~120 minutes.

[0086] In some embodiments, in step S6, the second film layer is transferred onto the first film layer by a cold pressing or hot pressing process, and the substrate on the second film layer is peeled off; then the third film layer is transferred onto the second film layer by a cold pressing or hot pressing process, and the substrate on the third film layer is peeled off, so as to form a solid electrolyte membrane.

[0087] In a third aspect, the present invention also provides a solid-state battery, comprising a positive electrode, a negative electrode, and a solid electrolyte membrane as described in any of the above embodiments. The solid electrolyte membrane is disposed between the positive and negative electrode to isolate the positive and negative electrode and serves as a lithium-ion conductor between the positive and negative electrode.

[0088] The composition and fabrication methods of solid-state batteries are as follows: The positive electrode can be a positive electrode used in various systems in this field.

[0089] In some embodiments, the positive electrode sheet includes a positive current collector and a positive active material layer coated on at least one side of the positive current collector. The positive active material layer includes a positive active material, a positive binder, a positive conductive agent, and a positive solid electrolyte. The preparation process of this type of positive electrode sheet is as follows: the positive active material, the positive solid electrolyte, the positive conductive agent, and the positive binder are mixed in a mass ratio of (70~90):(5~25):(1~5):(1~3), and the solvent N-methylpyrrolidone (NMP) is added. Then, the mixture is thoroughly stirred and mixed under vacuum to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated onto the positive current collector, and the positive current collector is dried at room temperature and then transferred to an oven for drying. Finally, the positive electrode sheet is obtained by cold pressing and slitting.

[0090] The positive electrode current collector can be made of foil with good conductivity and mechanical strength, such as aluminum, nickel, titanium, gold, silver, chromium, molybdenum, copper, stainless steel or carbon. In addition to foil, the positive electrode current collector can also be made of any one or more of the following forms: film, mesh, porous, foam or non-woven fabric.

[0091] The positive electrode active material is selected from one or more of lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), and lithium-rich manganese oxide (LRMO).

[0092] The positive electrode solid electrolyte may include the high-entropy sulfide electrolyte in any of the above embodiments, and the positive electrode solid electrolyte may also include at least one of other sulfide electrolytes, halide electrolytes, oxide electrolytes and polymer electrolytes.

[0093] The positive electrode conductive agent is selected from one or a combination of carbon black, Ketjen black, acetylene black, graphene, carbon nanotubes, carbon nanofibers, porous carbon, etc. In one example, the positive electrode conductive agent includes carbon black and carbon nanofibers, and the mass ratio of carbon black to carbon nanofibers is 1:(0.2~1.5).

[0094] The positive electrode binder is selected from any one of polyvinylidene fluoride (PVDF), fluoroethylene-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), and styrene-butadiene rubber (SBR), or a combination of several in any proportion.

[0095] The negative electrode can be a negative electrode used in various systems in this field.

[0096] In some embodiments, the negative electrode sheet includes a negative current collector and a negative active material layer coated on at least one side of the negative current collector. The negative active material layer includes a negative active material, a negative solid electrolyte, a negative binder, and a negative conductive agent. The preparation process of this type of negative electrode sheet is as follows: the negative active material, the negative solid electrolyte, the negative conductive agent, and the negative binder are mixed in a mass ratio of (70~90):(5~25):(1~5):(1~3), deionized water is added as a solvent, and then the mixture is thoroughly stirred under vacuum to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated onto the negative current collector, and the negative current collector is dried at room temperature and then transferred to an oven for drying. After cold pressing and slitting, the negative electrode sheet is obtained.

[0097] The negative electrode current collector can be made of foil with good conductivity and mechanical strength, such as aluminum, nickel, titanium, gold, silver, chromium, molybdenum, copper, stainless steel or carbon. In addition to foil, the negative electrode current collector can also be made of any one or more of the following forms: film, mesh, porous, foam or non-woven fabric.

[0098] The negative electrode active material is selected from one or more of the following: tin, artificial graphite (single crystal graphite, polycrystalline graphite, pyrolytic graphite, graphite fiber, etc.), natural graphite (bulk graphite, flake graphite, earthy graphite, etc.), soft carbon, hard carbon, pure silicon (crystalline silicon, amorphous silicon or organosilicon), silicon oxide, silicon carbide, and nano metal oxides (Fe2O3, CuO, SnO2, Mn3O4 nanoparticles).

[0099] The negative electrode solid electrolyte may include the high-entropy sulfide electrolyte in any of the above embodiments, and the negative electrode solid electrolyte may also include at least one of other sulfide electrolytes, halide electrolytes, oxide electrolytes and polymer electrolytes.

[0100] The negative electrode conductive agent is selected from one or more of carbon black, acetylene black, graphene, carbon nanotubes, and carbon nanofibers, or a mixture of two or more in any proportion.

[0101] The negative electrode binder is selected from any one of polyvinylidene fluoride (PVDF), fluoroethylene-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), and styrene-butadiene rubber (SBR), or a combination of several of these in any proportion.

[0102] In other embodiments, the negative electrode can be a lithium metal sheet, an indium metal sheet, or a lithium-containing alloy sheet (such as a lithium-tin-indium alloy sheet, a lithium-silicon alloy sheet, a lithium-tin alloy sheet, or a lithium-aluminum alloy sheet). For example, in one example, the negative electrode is selected from a lithium metal sheet.

[0103] An example of a solid-state battery assembly method is described below: A positive electrode is integrated onto one side of a solid electrolyte membrane, and a negative electrode is integrated onto the other side. The positive electrode, solid electrolyte membrane, and negative electrode are pressed together under a pressure of 500 MPa. The pressed cell is then sealed and packaged under a vacuum or inert atmosphere to obtain a solid-state lithium-ion battery.

[0104] The technical solution of the present invention will be described in detail below through several specific embodiments and comparative examples. Unless otherwise stated, the raw materials and reagents used in the following embodiments are commercially available products or can be prepared by conventional methods in the art.

[0105] Example 1 This embodiment provides a solid electrolyte membrane, which includes a first membrane layer, a second membrane layer, and a third membrane layer stacked sequentially along the thickness direction. The first membrane layer includes a halide electrolyte Li3InCl6, and the thickness of the first membrane layer is 30 μm. The second membrane layer includes a sulfide electrolyte Li... 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4, the thickness of the second film layer is 45 μm; the third film layer includes fluorinated polyimide, trialdehyde-based phloroglucinol-p-phenylenediamine covalent organic framework material (TpPa-1COF) and lithium salt LiTFSI, the mass content of the covalent organic framework material in the third film layer is 20%, and the mass content of the lithium salt in the third film layer is 13%; the thickness of the third film layer is 20 μm.

[0106] The preparation process of this solid electrolyte membrane is as follows: (1) The halide electrolyte Li3InCl6 and the binder PVDF were mixed evenly in xylene solvent at a mass ratio of 97:3 to obtain the first slurry; the first slurry was coated on aluminum foil and vacuum dried at 80°C for 12 hours to obtain the first film layer with a thickness of 30μm.

[0107] (2) Under an argon atmosphere, 1.835 mol Li₂S, 0.06 mol SnS₂, 0.21 mol SiS₂, 0.165 mol P₂S₅, 0.1 mol Sb₂S₅, and 0.1 mol Al₂S₃ were placed in a ball mill jar, and milling beads were added at a ball-to-material mass ratio of 30:1. The mixture was ball-milled at 100 rpm for 10 minutes, and then ball-milled at 600 rpm for 16 hours to obtain a homogeneous sulfide electrolyte raw material. The sulfide electrolyte raw material was placed in a crucible and sintered in a furnace at 200 °C for 20 hours. The sintered product was cooled to room temperature at a cooling rate of 5 °C / s to obtain Li₂S. 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4; Finally, the sulfide electrolyte Li with a D50 particle size of 1 μm was obtained by sieving. 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4.

[0108] (3) The sulfide electrolyte and the binder PVDF are mixed evenly in xylene solvent at a mass ratio of 97:3 to obtain a second slurry; the second slurry is coated on aluminum foil and vacuum dried at 80°C for 12 hours to obtain a second film layer with a thickness of 45μm.

[0109] (4) Disperse TpPa-1 COF in NMP solvent to obtain a dispersion. Add fluorinated aromatic dianhydride and aromatic diamine monomer in a molar ratio of 1:1 to the dispersion to carry out polymer reaction and form a mixture containing polyamic acid and COF material. Finally, add lithium salt LiTFSI in a preset mass ratio to the mixture and stir evenly.

[0110] (5) The mixture is cast into a film with a thickness of 20 μm on aluminum foil, and the cast film is heated from room temperature to 80°C and held for 30 minutes, then heated to 120°C and held for 40 minutes, and finally heated to 60°C and held for 90 minutes, so that the polyamic acid in the film forms fluorinated polyimide to form the third film layer.

[0111] (6) The second film layer is transferred onto the first film layer by a cold pressing process, and the aluminum foil on the second film layer is peeled off; the third film layer is transferred onto the second film layer by a cold pressing process, and the aluminum foil on the third film layer is peeled off, so as to make a solid electrolyte membrane.

[0112] Example 2 This embodiment provides a solid electrolyte membrane with the same system as in Example 1. The difference between this embodiment and Example 1 is that in step (2), a sulfide electrolyte raw material containing 1.95 mol Li₂S, 0.6 mol SiS₂, 0.05 mol Sb₂S₅, 0.04 mol MoS₃, 0.06 mol WS₃, and 0.1 mol Al₂S₃ is used to prepare a membrane with the chemical formula Li. 3.9 Si 0.6 (Sb 0.5 Mo 0.2 W 0.3 ) 0.2 Al 0.2 S4 is a sulfide electrolyte.

[0113] Example 3 This embodiment provides a solid electrolyte membrane with the same system as in Example 1. The difference between this embodiment and Example 1 is that in step (2), a sulfide electrolyte raw material containing 2.02 mol Li₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, 0.03 mol Al₂S₃, 0.05 mol In₂S₃, and 0.04 mol SrS is used to prepare a membrane with the chemical formula Li. 4.04 Si0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S4 is a sulfide electrolyte.

[0114] Example 4 This embodiment provides a solid electrolyte membrane with the same system as in Example 1. The difference between this embodiment and Example 1 is that in step (2), a sulfide electrolyte raw material containing 1.9 mol Li₂S, 0.05 mol Na₂S, 0.05 mol K₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, and 0.1 mol Al₂S₃ is used to prepare a membrane with the chemical formula Li. 3.8 Na 0.1 K 0.1 Si 0.6 Sb 0.2 Al 0.2 S4 is a sulfide electrolyte.

[0115] Example 5 This embodiment provides a solid electrolyte membrane with the same system as in Example 1. The difference between this embodiment and Example 1 is that in step (2), a sulfide electrolyte raw material containing 1.7 mol Li2S, 0.6 mol SiS2, 0.1 mol Sb2S5, 0.1 mol Al2S3, 0.2 mol Li2O, and 0.1 mol Li2Te is used to prepare a membrane with the chemical formula Li4Si. 0.6 Sb 0.2 Al 0.2 S 3.7 O 0.2 Te 0.1 Sulfide electrolytes.

[0116] Example 6 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the sulfide electrolyte in the second membrane layer is Li4Si. 0.4 Sb 0.4 Al 0.2 S4.

[0117] Example 7 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the sulfide electrolyte in the second membrane layer is Li4Si. 0.8 Sb 0.1 Al 0.1 S4.

[0118] Example 8 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the sulfide electrolyte in the second membrane layer is Li4Si. 0.4 Sb 0.3 Al 0.3 S4.

[0119] Example 9 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the sulfide electrolyte in the second membrane layer is Li. 2.5 Na 1.5 Si 0.6 Sb 0.2 Al 0.2 S4.

[0120] Example 10 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the sulfide electrolyte in the second membrane layer is Li4Si. 0.6 Sb 0.2 Al 0.2 S3Se.

[0121] Example 11 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the halide electrolyte in the first membrane layer is Li3YCl6.

[0122] Example 12 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the thickness of the first membrane layer is 1 μm.

[0123] Example 13 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the thickness of the first membrane layer is 30 μm.

[0124] Example 14 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the thickness of the first membrane layer is 50 μm.

[0125] Example 15 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the thickness of the first membrane layer is 100 μm.

[0126] Example 16 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the second membrane layer is 1 μm.

[0127] Example 17 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the second membrane layer is 30 μm.

[0128] Example 18 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the second membrane layer is 60 μm.

[0129] Example 19 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the second membrane layer is 100 μm.

[0130] Example 20 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the thickness of the second membrane layer is 200 μm.

[0131] Example 21 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the third membrane layer is 1 μm.

[0132] Example 22 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the third membrane layer is 10 μm.

[0133] Example 23 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the third membrane layer is 30 μm.

[0134] Example 24 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the third membrane layer is 50 μm.

[0135] Example 25 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the thickness of the third membrane layer is 100 μm.

[0136] Example 26 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the COF material in the third membrane layer is a 4-cyanobenzonic acid self-condensing triazine-boron oxide ring covalent organic framework (TB-COF).

[0137] Example 27 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the COF material in the third membrane layer is a benzobisthiazolyl covalent organic framework (BBT-COF).

[0138] Example 28 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the COF material in the third membrane layer is a covalent organic framework-5 (COF-5).

[0139] Example 29 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the mass content of COF material in the third membrane layer is 1%.

[0140] Example 30 This embodiment provides a solid electrolyte membrane with the same system as in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the mass content of COF material in the third membrane layer is 10%.

[0141] Example 31 This embodiment provides a solid electrolyte membrane with the same system as that in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the mass content of COF material in the third membrane layer is 15%.

[0142] Example 32 This embodiment provides a solid electrolyte membrane with the same system as that in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the mass content of COF material in the third membrane layer is 25%.

[0143] Example 33 This embodiment provides a solid electrolyte membrane with the same system as in Example 3. The difference between this embodiment and Example 3 is that the mass content of COF material in the third membrane layer is 30%.

[0144] Example 34 This embodiment provides a solid electrolyte membrane with the same system as that in Embodiment 3. The difference between this embodiment and Embodiment 3 is that the mass content of COF material in the third membrane layer is 50%.

[0145] Comparative Example 1 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the solid electrolyte membrane does not contain a first membrane layer.

[0146] Comparative Example 2 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the solid electrolyte membrane does not contain a second membrane layer.

[0147] Comparative Example 3 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the solid electrolyte membrane does not contain a third membrane layer.

[0148] Comparative Example 4 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the sulfide electrolyte in the second membrane layer is Li4SnS4.

[0149] Comparative Example 5 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the thickness of the second membrane layer is 500 μm.

[0150] Comparative Example 6 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the mass content of COF material in the third membrane layer is 0%.

[0151] Comparative Example 7 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the mass content of COF material in the third membrane layer is 55%.

[0152] Comparative Example 8 This comparative example provides a solid electrolyte membrane with the same system as Example 3. The difference between this comparative example and Example 3 is that the thickness of the third membrane layer is 150 μm.

[0153] The solid electrolyte membranes of Examples 1 to 34 and Comparative Examples 1 to 8 were assembled into solid-state batteries, and the DC internal resistance, rate performance and cycle performance of the solid-state batteries were tested to verify the improvement effect of the solid electrolyte membrane provided in the embodiments of this application on the cycle and rate performance of solid-state batteries. The relevant parameters of the solid electrolyte membrane are shown in Table 1, and the performance test results are shown in Table 2.

[0154] The assembly process of solid-state batteries is as follows: Positive electrode preparation: The positive electrode active material Li... 1.2 Ni 0.35 Mn 0.65 O2, the sulfide electrolyte, positive electrode conductive agent carbon fiber, and positive electrode binder hydrogenated nitrile rubber prepared in the examples or comparative examples are mixed thoroughly in xylene solvent at a mass ratio of 70:25:2:3 to obtain a positive electrode slurry; the positive electrode slurry is coated onto the positive electrode current collector aluminum foil, and after drying and cold pressing, an areal capacity of 4 mAh / cm² is obtained. 2 The positive electrode sheet is cut into 10mm diameter round pieces for later use.

[0155] Negative electrode preparation: The negative electrode active material (a graphite and silicon-carbon composite material with a mass ratio of 1:1, where the silicon content in the silicon-carbon composite material is 50%), the sulfide electrolyte prepared in the examples or comparative examples, the negative electrode conductive agent acetylene black, and the negative electrode binder styrene-butadiene rubber were mixed thoroughly in xylene solvent at a mass ratio of 70:25:2:3 to obtain a negative electrode slurry. The negative electrode slurry was coated onto a copper foil current collector, and after drying and cold pressing, an area capacity of 4.4 mAh / cm² was obtained. 2 The negative electrode sheet is cut into 10mm diameter round pieces for later use.

[0156] Solid-state battery assembly: A solid electrolyte membrane is integrated onto the side of the positive electrode sheet where the positive active material layer is located, and a negative electrode sheet is integrated onto the side of the solid electrolyte sheet opposite to the positive electrode sheet. These are then pressed together under a pressure of 500 MPa to obtain a battery cell. The cell undergoes processes such as settling, hot and cold pressing, and encapsulation to obtain a solid-state battery. The solid-state battery assembly process is completed in a glove box with an inert atmosphere.

[0157] DC internal resistance (DCR) test of solid-state battery at 50% charge: The solid-state battery was placed in a constant temperature chamber at 25°C and left to stand for 10 minutes. The battery was then charged at a constant current rate of 0.33C to 4.8V, followed by constant voltage charging to a current rate of 0.05C. After standing for 10 minutes, the battery was discharged at a current rate of 0.33C to 2.5V, and the theoretical capacity of the battery was measured. Then, the battery was charged at a constant current rate of 0.33C to 4.8V, followed by constant voltage charging to a current rate of 0.05C. After standing for 10 minutes, the battery was discharged at a current rate of 0.33C to 50% SOC. After standing for 1 hour, the initial voltage V1 of the battery was recorded. Then, the battery was discharged at a current rate of 4C for 30 seconds, and the voltage V2 of the battery after discharge was recorded. Finally, the DCR of the battery at 50% SOC was calculated using the following formula: DCR(Ω) = (V1 - V2) / I0.

[0158] Solid-state battery cycle performance testing: At room temperature (25°C), a low pressure of 1 MPa was applied to the solid-state battery, and within the test voltage range of 2.5V (discharge cutoff voltage) to 4.8V (charge cutoff voltage), the battery was first activated by two charge-discharge cycles at a 0.05C rate. Then, it was activated by 1C / 1C (where the 1C rated current density is 4 mA / cm²). 2 The solid-state battery was charged and discharged at a current rate of 1C, and the discharge capacity Q0 of the battery in the first cycle was recorded. After repeating this charge and discharge cycle for 300 cycles, the discharge capacity Q1 of the battery after the 300th charge and discharge cycle was recorded, and Q1 / Q0×100% was taken as the discharge capacity retention rate of the battery after 300 cycles.

[0159] Solid-state battery rate performance testing: At room temperature (25°C), a low pressure of 1 MPa was applied to the solid-state battery. The battery was then activated by two charge-discharge cycles within a voltage range of 2.5V to 4.8V at a 0.05C rate (where the 1C rated current density was 4 mA / cm²). 2 Then, within the test voltage range of 2.5V to 4.8V, the solid-state battery was charged in constant current and constant voltage mode at a constant rate of 0.33C; after resting for 15 minutes, the battery was discharged to the lower limit of the operating cutoff voltage at a constant rate of 0.33C; the above steps were repeated for three charge-discharge cycles, and the discharge capacity C in the third cycle was recorded. 0.33 Charge the solid-state battery at a constant current and constant voltage (DCV) rate of 0.33C; after resting for 15 minutes, discharge the battery to the lower limit of the operating cutoff voltage at a constant current rate of 0.5C; repeat this charge-discharge cycle three times. Charge the solid-state battery at a constant current and constant voltage (DCV) rate of 0.33C; after resting for 15 minutes, discharge the battery to the lower limit of the operating cutoff voltage at a constant current rate of 1C; repeat this charge-discharge cycle three times. Charge the solid-state battery at a constant current and constant voltage (DCV) rate of 0.33C; after resting for 15 minutes, discharge the battery to the lower limit of the operating cutoff voltage at a constant current rate of 2C; repeat this charge-discharge cycle three times, and record the discharge capacity C2 in the third cycle. Calculate the 2C fast-charging capacity retention rate of the solid-state battery using the following formula: (C2 / C 0.33 )×100%.

[0160] Table 1: Parameters of solid electrolyte membranes prepared in Examples 1 to 28 and Comparative Examples 1 to 8

[0161] Table 2: Performance test results of solid-state batteries prepared in Examples 1 to 28 and Comparative Examples 1 to 8

[0162] Comparing the test results of Examples 1 to 11 and Comparative Examples 2 and 4, it can be seen that, compared with Comparative Example 2 which does not introduce a second film layer or Comparative Example 4 which uses a conventional sulfide electrolyte, the embodiments of this application introduce a high-entropy sulfide electrolyte in the intermediate second film layer to significantly reduce the interfacial impedance of the solid-state battery and improve its cycle and rate stability. Specifically, in the second film layer of the solid electrolyte membrane, the multi-principal solid solution structure of the sulfide electrolyte effectively suppresses grain boundary migration and phase transitions between film layers, improves interfacial chemical stability and mechanical flexibility, and reduces Young's modulus to achieve "flexible wetting" with the cathode material, thereby maintaining a stable ion pathway under a low stacking pressure of 1 MPa. Simultaneously, the sulfide electrolyte in the second film layer, in conjunction with the COF material in the third film layer, induces the formation of a protective layer rich in LiF or Li3N to help the solid electrolyte membrane construct a bistable interface system between the positive and negative electrodes. In Comparative Example 2, where the first and third layers of the solid electrolyte membrane are in direct contact, there is a lack of an intermediate layer with suitable ionic conductivity and shaping properties between them. This leads to increased interfacial resistance and easy delamination between the first and third layers, resulting in severe degradation of the solid-state battery's cycle and rate performance. Similarly, in Comparative Example 4, where a conventional sulfide electrolyte is used in the second layer, the single composition of the conventional sulfide electrolyte increases interfacial side reactions between the second and first / third layers, raising the risk of dendrite penetration. This also leads to increased internal resistance and severe degradation of cycle and rate performance in the solid-state battery.

[0163] Comparing the test results of Example 3 and Comparative Examples 1 and 3, it can be seen that when the first or third film layer is not introduced into the solid electrolyte membrane, the interface between the solid electrolyte membrane and the positive or negative electrode will be incompatible, resulting in an increase in side reactions between the solid electrolyte membrane and the positive or negative electrode, which in turn leads to a rapid decay of the cycle life and rate performance of the solid battery during charging and discharging.

[0164] Comparing the test results of Examples 3, 16 to 20 and Comparative Example 5, it can be seen that when the thickness of the second film layer is low (e.g., 1 μm), although it can reduce the ion transport resistance within the solid electrolyte membrane, the insufficient mechanical strength of the intermediate film layer makes it easily penetrated by lithium dendrites, leading to an increase in the internal resistance of the solid battery and a decrease in cycle life and rate performance. When the thickness of the second film layer is within a suitable range of 30-60 μm, the solid electrolyte membrane can achieve both good ionic conductivity and mechanical strength, minimizing the interfacial impedance within the solid electrolyte membrane, thereby optimizing the cycle performance and rate performance of the solid battery. When the thickness of the second film layer is relatively thick (e.g., 60-200 μm), it leads to a prolonged ion diffusion path within the solid electrolyte membrane, causing the internal resistance of the solid battery to gradually increase and the fast-charging performance of the battery to decrease. If the thickness of the second film layer in Comparative Example 5 is too thick (e.g., the thickness exceeds 200 μm), the ionic conductivity of the solid electrolyte membrane will be too low and the rigidity will be too high, making it difficult to meet the performance requirements of flexible solid-state batteries. This will cause the cycle capacity retention rate and fast charging capacity retention rate of the solid-state battery to drop sharply and become unusable.

[0165] Comparing the test results of Examples 3, 12 to 15 and Comparative Example 1, it can be seen that in Comparative Example 1, the solid electrolyte membrane lacks a first membrane layer, causing the high-entropy sulfide electrolyte in the second membrane layer to be directly exposed to the high-voltage positive electrode surface. Since the electrochemical window of the sulfide electrolyte cannot reach 4.5V, the solid electrolyte membrane in the comparative example is oxidized and decomposed on the positive electrode side, leading to a sharp increase in the internal resistance of the solid-state battery and a rapid decrease in cycle and rate performance.

[0166] Furthermore, the test results from Examples 3, 12 to 15 show that when the thickness of the first film layer is within the suitable range of 20-50 μm, it can provide sufficient oxidation resistance for the solid electrolyte membrane to adapt to the high-voltage positive electrode, without excessively increasing the ion transport path and causing kinetic lag, thereby achieving optimal cycle life and rate performance of the solid battery. When the thickness of the first film layer is low, as in Example 12 (e.g., 1 μm), although it can reduce the ion transport path within the solid electrolyte membrane, it cannot suppress the solid electrolyte membrane from resisting oxidation and decomposition on the positive electrode side, resulting in a decrease in battery cycle stability. When the thickness of the first film layer is thick, as in Example 15 (e.g., 50-100 μm), it will lead to an extension of the ion diffusion path within the solid electrolyte membrane, causing the internal resistance of the solid battery to gradually increase and the fast-charging performance of the battery to decrease.

[0167] Comparing the test results of Examples 3, 21 to 25 and Comparative Example 3, it can be seen that the solid electrolyte membrane in Comparative Example 3 does not contain a third membrane layer, which makes it difficult for the solid electrolyte membrane to maintain good interfacial contact with the negative electrode under low pressure. As a result, the solid electrolyte membrane is difficult to adapt to the volume change of the negative electrode during cycling, which leads to the deterioration of the stability of the solid electrolyte membrane contact interface structure. Consequently, the cycle life and rate performance of the solid battery rapidly decline during charging and discharging.

[0168] Comparing the test results of Examples 3 and 21 to 25, it can be seen that when the thickness of the third film layer is within the suitable range of 10~30μm, the third film layer combines good flexibility, effective adhesion to the negative electrode, and a suitable ion transport path, resulting in optimal cycle life and rate performance of the solid-state battery. As in Example 15, when the thickness of the third film layer is low (e.g., 1μm), although it can reduce the ion transport path within the solid electrolyte membrane, the insufficient mechanical strength of the third film layer makes it difficult to resist dendrite penetration and adapt to the volume expansion of the negative electrode, leading to reduced stability of the negative electrode interface of the solid electrolyte membrane and affecting the cycle life and rate performance of the solid-state battery. As shown in Example 25, when the thickness of the third film layer is relatively thick (e.g., 50~150μm), it leads to a prolonged ion diffusion path within the solid electrolyte membrane, causing the internal resistance of the solid-state battery to gradually increase and the fast-charging performance of the battery to decrease.

[0169] Comparing the test results of Examples 3, 26 to 28 and Comparative Example 6, it can be seen that Examples 3 and 26 to 28 use COF materials linked by β-ketoenamine bonds, triazine rings, benzothiazoles, and imine bonds as polymer electrolyte fillers in the third film layer of the solid electrolyte. This results in significantly better cycle performance and rate performance of the solid batteries in Examples 3 and 26 compared to Comparative Example 6, which does not introduce COF materials in the third film layer. In Comparative Example 6, the solid electrolyte film lacks ordered channels and heteroatom sites provided by COF materials on the negative electrode side, leading to low ionic conductivity and high interfacial impedance, which increases the internal resistance of the battery and degrades cycle and rate performance. In contrast, the solid electrolyte film provided in this application utilizes the periodic nanopores of COF materials to construct a continuous ion transport path on the negative electrode side. Furthermore, the heteroatoms in the COF material framework can induce the formation of a dense, high-modulus LiF / Li3N composite interfacial layer in situ on the lithium metal surface, thereby significantly reducing the interfacial impedance of the solid electrolyte film and suppressing dendrite growth.

[0170] Comparing the test results of Examples 3, 29 to 34 and Comparative Examples 6 and 7, it can be seen that for the solid electrolyte membranes provided in the examples, as the mass content of COF material in the third film layer gradually increases from 0% to 30%, the performance of the solid-state battery shows a trend of first significantly improving and then tending to saturate or even slightly decreasing. In Comparative Example 6, the solid electrolyte membrane lacks ordered ion channels and interface phase regulation sites on the negative electrode side because the third film layer does not contain COF material, resulting in extremely high interfacial impedance. When the mass content of COF material in the third film layer increases to a certain level, the solid electrolyte membrane can construct an efficient continuous ion transport network in the third film layer, provide sufficient heteroatoms to form a uniform and dense LiF / Li3N protective layer in situ, and maintain the flexibility and integrity of the third film, thereby optimizing the cycle and rate performance of the battery. As in Comparative Example 7, when the mass content of COF material in the third membrane layer exceeds 30%, the COF material particles in the third membrane layer are prone to agglomeration, which destroys the continuous phase of polymer electrolyte in the third membrane layer, leading to increased brittleness of the solid electrolyte membrane and affected interfacial contact. This, in turn, increases the internal resistance of the solid battery and reduces cycle and fast charging performance.

[0171] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Anyone skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention. Anyone skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention.

Claims

1. A solid state electrolyte membrane, characterized by, include: A first membrane layer, the first membrane layer comprising a halide electrolyte; A second membrane layer is disposed on the first membrane layer, and the second membrane layer includes a sulfide electrolyte, wherein the sulfide electrolyte includes Li. 4±x-y A y (M1 a M2 b M3 c S4 δ X δ Wherein, 0≤x≤1.5, 0≤y≤1.5, y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A includes at least one of Na and K; M1 includes at least one of Ge, Sn, Si, P, As, and B; M2 includes at least one of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 includes at least one of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; and X includes at least one of O, Se, and Te. A third membrane layer is disposed on the second membrane layer, and the third membrane layer comprises fluorinated polyimide and a covalent organic framework material.

2. The solid electrolyte membrane according to claim 1, characterized in that, The thickness of the first film layer is 1~100 μm, the thickness of the second film layer is 1~200 μm, and the thickness of the third film layer is 1~100 μm.

3. The solid electrolyte membrane according to claim 1 or 2, characterized in that, The thickness of the first film layer is 10~30 μm; and / or, The thickness of the second film layer is 30~60 μm; and / or, The thickness of the third film layer is 10~30 μm.

4. The solid electrolyte membrane according to claim 1, characterized in that, The covalent organic framework material in the third membrane layer has a mass content of 10~30wt%.

5. The solid electrolyte membrane according to claim 1, characterized in that, The covalent organic framework material has nanopores; the framework of the covalent organic framework material contains heteroatoms, which include at least one of nitrogen, oxygen, fluorine or sulfur.

6. The solid electrolyte membrane according to claim 5, characterized in that, the covalent organic framework material has a specific surface area of greater than 500 m 2 / g; and / or, The pore size of the nanopore is 1~3 nm; and / or, When the covalent organic framework material is in the form of particles, the particle size of the granular covalent organic framework material is 50 nm to 5 μm; when the covalent organic framework material is in the form of sheets, the sheet size of the sheet-like covalent organic framework material is 50 nm to 5 μm, and the thickness of the sheet-like covalent organic framework material is 2 to 100 nm.

7. The solid electrolyte membrane according to claim 1, characterized in that, The covalent organic framework material is formed by covalently connecting building units, which are connected by linking groups, including at least one of imine bonds, hydrazone bonds, β-ketoenamine bonds, borate ester bonds, triazine rings, benzoxazole, benzothiazole, imide bonds, or urea bonds.

8. The solid electrolyte membrane according to claim 1, characterized in that, The halide electrolytes include Li3YCl6, Li3YBr6, Li3InCl6, Li3ScCl6, Li2ZrCl6, Li2HfCl6, Li3LuCl6, Li3ErCl6, and Li3Y (1 z) M z At least one of Cl6, wherein M includes at least one of rare earth elements and transition metal elements, and 0≤z≤0.

5.

9. The solid electrolyte membrane according to claim 1, characterized in that, The third film layer also includes a lithium salt, the molar content of which is 5-30 mol%, and the lithium salt includes at least one of LiTFSI, LiFSI, LiPF6 or LiBOB.

10. A solid-state battery, characterized in that, Includes the solid electrolyte membrane according to any one of claims 1 to 9.

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