Composite solid electrolyte membrane and preparation method thereof, solid-state battery, battery pack and electric equipment

Abstract

The invention specifically discloses a composite solid electrolyte membrane and a preparation method thereof, a solid-state battery, a battery pack and electric equipment, the composite solid electrolyte membrane comprises an inorganic solid electrolyte, and the inorganic solid electrolyte comprises a small-particle first inorganic solid electrolyte and a large-particle second inorganic solid electrolyte; and the polymer electrolyte comprises a polymer matrix and a lithium salt, the lithium salt is doped in the polymer matrix, and the polymer electrolyte coats at least part of the surface of the inorganic solid electrolyte in the form of a fiber network. The inorganic solid electrolyte is subjected to multi-scale grain composition, and at least part of the surface of the inorganic solid electrolyte is coated with the lithiated polymer electrolyte in the form of a crude fiber network, so that the ionic conductivity and the mechanical strength of the composite solid electrolyte membrane can be effectively improved.

Description

Technical Field

[0001] This application belongs to the field of solid-state batteries, specifically relating to a composite solid-state electrolyte membrane and its preparation method, a solid-state battery, a battery pack, and an electrical device. Background Technology

[0002] With the surge in demand for high-energy-density and high-safety energy storage, all-solid-state lithium batteries are considered the core direction of next-generation battery technology. As the core component of solid-state batteries, solid electrolyte membranes need to have high ionic conductivity, low interfacial impedance, and excellent machinability. The current mainstream technical routes include inorganic ceramic electrolytes, polymer electrolytes, and organic-inorganic composite electrolytes, but all of them have significant technical bottlenecks, mainly reflected in the following aspects: (1) Single inorganic electrolyte system: Although sintered ceramic electrolytes have high ionic conductivity, the rigid interface results in a low electrode / electrolyte contact area (<60%) and an interfacial impedance as high as 10. 3 Ω·cm 2 The magnitude is also significant. Simultaneously, it exhibits brittle characteristics (fracture toughness <2 MPa·m). 1 / 2 (1) The film thickness is difficult to reduce to below 50 μm, which seriously restricts the improvement of the volumetric energy density of solid-state batteries. (2) Pure polymer electrolyte system: Pure polymer electrolyte system relies on chain segment movement to conduct ions, and the room temperature conductivity is generally low. Although plasticizer doping can improve its conductivity, it sacrifices its mechanical strength (tensile strength <1MPa) and deteriorates its thermal stability. (3) Traditional organic-inorganic composite electrolyte: The wet process introduces solvent residue, which easily leads to side reactions, and drying shrinkage leads to microcracks; and single-size fillers are prone to local agglomeration, and inorganic fillers are randomly distributed and cannot form continuous ion channels.

[0003] Therefore, existing solid electrolyte membranes suffer from problems such as low ionic conductivity and poor mechanical strength. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in related technologies. Therefore, one objective of this application is to provide a composite solid electrolyte membrane and its preparation method, as well as a solid-state battery, battery pack, and electrical device. This application effectively improves the ionic conductivity and mechanical strength of the composite solid electrolyte membrane by performing multi-scale particle gradation on the inorganic solid electrolyte and simultaneously encapsulating at least a portion of the surface of the inorganic solid electrolyte with a lithium-ionized polymer electrolyte in the form of a coarse fiber network.

[0005] The first aspect of this application discloses a composite solid electrolyte membrane. According to an embodiment of this application, the composite solid electrolyte membrane comprises: An inorganic solid electrolyte, comprising a first inorganic solid electrolyte and a second inorganic solid electrolyte, wherein the particle size D of the first inorganic solid electrolyte is...50,A The particle size D is smaller than that of the second inorganic solid electrolyte. 50,B ; A polymer electrolyte comprising a polymer matrix and a lithium salt, wherein the lithium salt is doped in the polymer matrix, and the polymer electrolyte is coated on at least a portion of the surface of the inorganic solid electrolyte in the form of a fibrous network.

[0006] According to the composite solid electrolyte membrane of the above embodiments of this application, by performing multi-scale particle gradation on the inorganic solid electrolyte, the bulk conductivity and interfacial contact of the composite solid electrolyte membrane can be simultaneously improved, and the interfacial impedance can be reduced. Simultaneously, the polymer electrolyte coating at least a portion of the surface of the inorganic solid electrolyte can effectively improve the flexibility of the composite solid electrolyte membrane, and the lithium salt doped in the polymer electrolyte can improve the ion conduction performance of the polymer electrolyte. Furthermore, the polymer electrolyte coating at least a portion of the surface of the inorganic solid electrolyte in the form of a coarse fiber network can enhance the mechanical strength of the composite solid electrolyte membrane while facilitating lithium-ion transport.

[0007] In addition, the composite solid electrolyte membrane according to the above embodiments of this application may also have the following additional technical features: In some embodiments of this application, the inorganic solid electrolyte includes at least one of oxide solid electrolyte, sulfide solid electrolyte, and halide solid electrolyte.

[0008] In some embodiments of this application, the oxide solid electrolyte includes a first oxide solid electrolyte and a second oxide solid electrolyte, wherein the particle size D of the first oxide solid electrolyte is... 50,A The particle size is 0.2µm~0.5µm, and the maximum particle size D of the first oxide solid electrolyte is... max,A <1.0µm; the particle size D of the second oxide solid electrolyte 50,B The particle size ranges from 0.8µm to 2.0µm, and the maximum particle size D of the second oxide solid electrolyte is... max,B <4.0µm.

[0009] In some embodiments of this application, the sulfide solid electrolyte includes a first sulfide solid electrolyte and a second sulfide solid electrolyte, wherein the particle size D of the first sulfide solid electrolyte is... 50,A The particle size ranges from 0.5µm to 2.0µm, and the maximum particle size D of the first sulfide solid electrolyte is... max,A <3.5µm; the particle size D of the second sulfide solid electrolyte 50,B The particle size ranges from 4.0 µm to 8.0 µm, and the maximum particle size D of the second sulfide solid electrolyte is... max,B <12µm.

[0010] In some embodiments of this application, the particle size distribution uniformity index K1 of the first inorganic solid electrolyte is 0.9~1.2; and / or, the particle size distribution uniformity index K2 of the second inorganic solid electrolyte is 0.8~1.3.

[0011] In some embodiments of this application, the mass ratio of the second inorganic solid electrolyte to the first inorganic solid electrolyte is (85:5) to (35:35); and / or, the mass ratio of the polymer matrix, the second inorganic solid electrolyte, and the first inorganic solid electrolyte is (10:85:5) to (30:35:35); and / or, the mass ratio of the polymer matrix to the lithium salt is (95:5) to (70:30).

[0012] In some embodiments of this application, the oxide solid electrolyte includes at least one of LATP, LAGP, LLZO, and LLZTO; and / or, the sulfide solid electrolyte includes at least one of LPSX1 and LM1PS, wherein X1 is selected from at least one halogen element and M1 is selected from at least one Group IVA element; and / or, the halide solid electrolyte includes at least one of a Li-M2-X2 ternary compound, wherein X2 is selected from at least one halogen element and M2 is selected from at least one Group IIIA and Group IIIB element.

[0013] In some embodiments of this application, the polymer matrix includes at least one of the following: ethylene-methyl acrylate copolymer, styrene-butadiene-styrene front copolymer, hydrogenated styrene-butadiene block copolymer, polyurethane, polyamide, polyimide, styrene-butadiene rubber, hydrogenated nitrile rubber, acrylonitrile-butadiene-styrene copolymer, polybutyl acrylate, polyethylene terephthalate, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, polymethyl methacrylate, and cellulose polymers.

[0014] In some embodiments of this application, the lithium salt includes at least one of LiFSI, LiTFSI, LiClO4, and LiPF6.

[0015] A second aspect of this application provides a method for preparing the composite solid electrolyte membrane described in the first aspect. According to embodiments of this application, the method includes: The polymer matrix and lithium salt are mixed and stirred, heated and sheared to form a first molten slurry, which is then extruded, cooled and shaped, and granulated to obtain lithium-ionized polymer electrolyte particles. The lithium-ionized polymer electrolyte particles, the first inorganic solid electrolyte, and the second inorganic solid electrolyte are mixed and stirred, heated and sheared to form a second molten slurry, which is then extruded and cast into a film, cooled and shaped to obtain a composite solid electrolyte membrane.

[0016] The method for preparing composite solid electrolyte membranes according to the above embodiments of this application utilizes a dry melt casting process to achieve uniform composite formation of a lithiated polymer electrolyte, a first inorganic solid electrolyte, and a second inorganic solid electrolyte under solvent-free conditions, effectively avoiding interfacial side reactions and porosity defects. Furthermore, the combined casting-hot pressing process enables low-cost, large-scale production. In addition, this method employs a high-speed shear-induced lithiation polymer electrolyte system to form a coarse fiber network; its three-dimensional interconnected structure enhances the mechanical strength of the solid electrolyte membrane while facilitating lithium-ion transport.

[0017] In addition, the method for preparing the composite solid electrolyte membrane according to the above embodiments of this application may also have the following additional technical features: In some embodiments of this application, a first twin-screw extruder is used to heat and shear the mixture of the polymer matrix and the lithium salt to form the first molten slurry, which is then extruded; and / or, a second twin-screw extruder is used to heat and shear the mixture of the lithium-ionized polymer electrolyte particles, the first inorganic solid electrolyte, and the second inorganic solid electrolyte to form the second molten slurry, which is then extruded and cast into a film.

[0018] The first twin-screw extruder has a melt extrusion temperature of 50℃~300℃, a screw speed of 10r / min~200r / min, and a cooling and setting temperature of 5℃~25℃; and / or, the second twin-screw extruder has a melt extrusion temperature of 100℃~250℃, a screw speed of 10r / min~200r / min, a cooling and setting temperature of 5℃~25℃, and a traction speed of 0.1m / min~1m / min.

[0019] A third aspect of this application discloses a solid-state battery. According to embodiments of this application, the solid-state battery includes a composite solid-state electrolyte membrane as described in the first aspect and a composite solid-state electrolyte membrane prepared by the method of the second aspect. This facilitates the solid-state battery to possess high ionic conductivity and interfacial stability, low interfacial impedance, and excellent mechanical strength.

[0020] In a fourth aspect, this application proposes a battery pack. According to embodiments of this application, the battery pack includes a composite solid-state electrolyte membrane as described in the first aspect, a composite solid-state electrolyte membrane prepared by the method of the second aspect, or a solid-state battery as described in the third aspect. This facilitates the battery pack to possess high ionic conductivity and interfacial stability, low interfacial impedance, and excellent mechanical strength.

[0021] This application discloses an electrical device in its fifth aspect. According to embodiments of this application, the electrical device includes a composite solid-state electrolyte membrane as described in the first aspect, a composite solid-state electrolyte membrane prepared by the method of the second aspect, a solid-state battery as described in the third aspect, or a battery pack as described in the fourth aspect. The features and advantages described above for solid-state batteries also apply to this electrical device, and will not be repeated here.

[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0023] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of the composite solid electrolyte membrane according to an embodiment of this application. Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0025] In this application, 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.

[0026] The first aspect of this application discloses a composite solid electrolyte membrane. According to embodiments of this application, refer to the appendix... Figure 1 The composite solid electrolyte membrane includes: an inorganic solid electrolyte, which comprises a first inorganic solid electrolyte and a second inorganic solid electrolyte, wherein the particle size D of the first inorganic solid electrolyte is... 50,A The particle size D is smaller than that of the second inorganic solid electrolyte. 50,BThe polymer electrolyte comprises a polymer matrix and a lithium salt, wherein the lithium salt is doped into the polymer matrix (i.e., a lithium-doped polymer electrolyte), and the polymer electrolyte is coated on at least a portion of the surface of the inorganic solid electrolyte in the form of a fibrous network. Therefore, by employing multi-scale particle gradation of the inorganic solid electrolyte, this application can simultaneously improve the bulk conductivity and interfacial contact of the composite solid electrolyte membrane, while reducing interfacial impedance. Simultaneously, the polymer electrolyte coating on at least a portion of the surface of the inorganic solid electrolyte effectively enhances the flexibility of the composite solid electrolyte membrane, and the lithium salt doped in the polymer electrolyte improves its ion-conducting properties. Furthermore, the polymer electrolyte coating on at least a portion of the surface of the inorganic solid electrolyte in the form of a coarse fibrous network enhances the mechanical strength of the composite solid electrolyte membrane while facilitating lithium-ion transport.

[0027] The beneficial effects that the composite solid electrolyte membrane proposed in this application can achieve are described in detail below: The composite solid electrolyte membrane of this application comprises an inorganic solid electrolyte and a polymer electrolyte. The inorganic solid electrolyte is multi-scale particle size distribution. Large particles of the second inorganic solid electrolyte form the framework of the composite solid electrolyte membrane, effectively reducing interfacial impedance. Small particles of the first inorganic solid electrolyte fill the gaps, effectively improving the bulk conductivity of the composite solid electrolyte membrane, thus achieving the densest packing and simultaneously improving the bulk conductivity and interfacial contact of the composite solid electrolyte membrane, reducing interfacial impedance. Simultaneously, the polymer electrolyte is wrapped in a fibrous network on at least a portion of the surface of the inorganic solid electrolyte, giving the composite solid electrolyte membrane good flexibility. Furthermore, the lithium salt doped in the polymer electrolyte increases the lithium-ion conduction network within the polymer electrolyte, giving the lithiated polymer solid electrolyte a certain degree of ion conduction performance, further reducing interfacial impedance. In addition, the polymer electrolyte, in the form of a coarse fibrous network, coats at least a portion of the surface of the inorganic solid electrolyte. Its three-dimensional interconnected structure enhances the mechanical strength of the composite solid electrolyte membrane while facilitating lithium-ion transport, thereby contributing to improved mechanical strength and electrochemical performance of the composite solid electrolyte membrane.

[0028] In the embodiments of this application, the specific type of the inorganic solid electrolyte is not particularly limited. Those skilled in the art can select it according to actual needs. As some preferred embodiments, the inorganic solid electrolyte includes at least one of oxide solid electrolyte, sulfide solid electrolyte and halide solid electrolyte.

[0029] According to some specific embodiments of this application, the above-mentioned oxide solid electrolyte includes a first oxide solid electrolyte and a second oxide solid electrolyte, wherein the particle size D of the first oxide solid electrolyte is... 50,AThe particle size is 0.2µm to 0.5µm (e.g., it can be 0.2µm, 0.25µm, 0.3µm, 0.35µm, 0.4µm, 0.45µm, 0.5µm, or any range between the two), and the maximum particle size D of the first oxide solid electrolyte is... max,A <1.0µm; Particle size D of the second oxide solid electrolyte 50,B The particle size is 0.8µm to 2.0µm (e.g., it can be 0.8µm, 1.0µm, 1.2µm, 1.4µm, 1.6µm, 1.8µm, 2.0µm, or any range between the two), and the maximum particle size D of the second oxide solid electrolyte is... max,B <4.0µm. By performing multi-scale particle gradation on the above-mentioned oxide solid electrolytes, the large particles of the second oxide solid electrolyte construct the framework of the composite solid electrolyte membrane, which can effectively reduce the interfacial impedance. The small particles of the first oxide solid electrolyte fill the gaps, which can effectively improve the bulk conductivity of the composite solid electrolyte membrane, thereby achieving the densest packing and simultaneously improving the bulk conductivity and interfacial contact of the composite solid electrolyte membrane, reducing the interfacial impedance.

[0030] In the embodiments of this application, the specific type of oxide solid electrolyte is not particularly limited. Those skilled in the art can select according to actual needs. As some preferred embodiments, the oxide solid electrolyte includes at least one of LATP, LAGP, LLZO, and LLZTO, more preferably at least one of LATP and LLZTO.

[0031] According to some specific embodiments of this application, the above-mentioned sulfide solid electrolyte includes a first sulfide solid electrolyte and a second sulfide solid electrolyte, wherein the particle size D of the first sulfide solid electrolyte is... 50,A The particle size ranges from 0.5µm to 2.0µm, and the maximum particle size D of the first sulfide solid electrolyte is... max,A <3.5µm; Particle size D of the second sulfide solid electrolyte 50,B The particle size ranges from 4.0 µm to 8.0 µm, and the maximum particle size D of the second sulfide solid electrolyte is... max,B <12µm. By performing multi-scale particle gradation on the above-mentioned sulfide solid electrolyte, the large particles of the second sulfide solid electrolyte construct the framework of the composite solid electrolyte membrane, which can effectively reduce the interfacial impedance. The small particles of the first sulfide solid electrolyte fill the gaps, which can effectively improve the bulk conductivity of the composite solid electrolyte membrane, thereby achieving the densest packing and simultaneously improving the bulk conductivity and interfacial contact of the composite solid electrolyte membrane, reducing the interfacial impedance.

[0032] In the embodiments of this application, the specific type of the sulfide solid electrolyte is not particularly limited, and those skilled in the art can select it according to actual needs. As some preferred embodiments, the sulfide solid electrolyte includes at least one of LPSX1 and LM1PS, wherein X1 is selected from at least one halogen element, and M1 is selected from at least one Group IVA element. Optionally, X1 is selected from at least one of Cl, Br, and I; M1 is selected from at least one of Ge, Sn, and Si. More preferably, at least one of LPSCl, LPSClBr, and LGePS is selected.

[0033] In the embodiments of this application, the specific type of the sulfide solid electrolyte is not particularly limited, and those skilled in the art can select it according to actual needs. As some preferred embodiments, the halide solid electrolyte includes at least one of the ternary compounds Li-M2-X2, wherein X2 is selected from at least one halogen element, and M2 is selected from at least one element of Group IIIA and Group IIIB. Optionally, X2 is selected from at least one of F, Cl, Br, and I; and M2 is selected from at least one of In, Al, Y, Ho, Sm, Lu, Tb, Dy, Er, Tm, and Sc. The particle size D of the above-mentioned sulfide solid electrolyte is... 50 The range is 0.2µm to 12.0µm, D max <20.0µm. More preferably, it is at least one of Li-In-Cl, Li-Y-Cl, and Li-In-Cl-F.

[0034] According to some specific embodiments of this application, the particle size distribution uniformity index K1 of the first inorganic solid electrolyte is 0.9~1.2, for example, it can be 0.9, 0.95, 1.0, 1.1, 1.15, 1.2 or any range between the two. It can be seen that the particle size distribution uniformity of the first inorganic solid electrolyte is good, which can further facilitate the multi-scale particle gradation of the inorganic solid electrolyte, thereby further effectively improving the bulk conductivity of the composite solid electrolyte membrane and further reducing the interfacial impedance.

[0035] According to some specific embodiments of this application, the particle size distribution uniformity index K2 of the second inorganic solid electrolyte is 0.8~1.3, for example, it can be 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 or any range between the two. It can be seen that the particle size distribution uniformity of the second inorganic solid electrolyte is good, which can further facilitate the multi-scale particle gradation of the inorganic solid electrolyte, thereby further effectively improving the bulk conductivity of the composite solid electrolyte membrane and further reducing the interfacial impedance.

[0036] It should be noted that the particle size distribution uniformity index , is a commonly used index to describe the uniformity of particle size distribution. Among them, D90 D represents the particle size at which the cumulative number distribution of particles reaches 90%. 50 D represents the particle size at which the cumulative number distribution of particles reaches 50%. 10 This indicates the particle size corresponding to a cumulative particle count distribution reaching 10%.

[0037] According to some specific embodiments of this application, the mass ratio of the second inorganic solid electrolyte to the first inorganic solid electrolyte is (85:5) to (35:35), for example, it can be 85:5, 70:10, 60:15, 45:25, 35:35 or any range between the two. By limiting the mass ratio of the second inorganic solid electrolyte to the first inorganic solid electrolyte within the above range, it is more beneficial to the multi-scale particle size distribution of the inorganic solid electrolyte, and it is more beneficial to the second inorganic solid electrolyte with large particles to construct the framework of the composite solid electrolyte membrane, which can effectively reduce the interfacial impedance. The first inorganic solid electrolyte with small particles fills the gaps, which can effectively improve the bulk conductivity of the composite solid electrolyte membrane, thereby further improving the bulk conductivity of the composite solid electrolyte membrane and further reducing the interfacial impedance.

[0038] According to some specific embodiments of this application, the mass ratio of the polymer matrix, the second inorganic solid electrolyte, and the first inorganic solid electrolyte is (10:85:5) to (30:35:35), for example, it can be 10:85:5, 15:70:15, 20:60:20, 30:35:35, or any range between the two. By limiting the mass ratio of the polymer matrix, the second inorganic solid electrolyte, and the first inorganic solid electrolyte to the above range, it is more beneficial to the multi-scale particle size distribution of the inorganic solid electrolyte, thereby further effectively improving the bulk conductivity of the composite solid electrolyte membrane and further reducing the interfacial impedance; at the same time, it is more beneficial to improve the flexibility of the composite solid electrolyte membrane.

[0039] According to some specific embodiments of this application, the mass ratio of the polymer matrix to the lithium salt is (95:5) to (70:30), for example, it can be 95:5, 85:15, 75:25, 70:30 or any range between the two. By limiting the mass ratio of the polymer matrix to the lithium salt to the above range, the lithium-ion conduction network in the polymer electrolyte can be further increased, so that the lithium-ionized polymer solid electrolyte has a certain ion conduction performance, and the interface impedance can be further reduced.

[0040] In the embodiments of this application, the specific type of polymer matrix is ​​not particularly limited, and those skilled in the art can select it according to actual needs. As some preferred embodiments, the polymer electrolyte includes at least one of the following: ethylene-methyl acrylate copolymer, styrene-butadiene-styrene front copolymer, hydrogenated styrene-butadiene block copolymer, polyurethane, polyamide, polyimide, styrene-butadiene rubber, hydrogenated nitrile rubber, acrylonitrile-butadiene-styrene copolymer, polybutyl acrylate, polyethylene terephthalate, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, polymethyl methacrylate, and cellulose polymers.

[0041] In the embodiments of this application, the specific types of lithium salts are not particularly limited, and those skilled in the art can select them according to actual needs. As some preferred embodiments, the lithium salts include at least one of LiFSI, LiTFSI, LiClO4 and LiPF6.

[0042] A second aspect of this application provides a method for preparing the composite solid electrolyte membrane of the first aspect. According to embodiments of this application, the method includes: S100: The polymer matrix and lithium salt are mixed and stirred, heated and sheared to form a first molten slurry, which is then extruded, cooled and shaped, and granulated to obtain lithium-ionized polymer electrolyte particles. In this step, a certain proportion of polymer matrix and lithium salt are weighed out and mixed evenly at room temperature. Then, the mixture is heated and sheared under certain temperature and stirring conditions using a first twin-screw extruder to ensure thorough mixing and melting into a stable slurry. After extrusion through a specific extruder die, it is directly cooled, shaped, and granulated. Thus, pre-lithiation of the polymer matrix can effectively increase the lithium-ion network in the polymer electrolyte, giving the lithium-ionized polymer solid electrolyte certain ion-conducting properties and further reducing interfacial impedance.

[0043] In some specific embodiments, the above-mentioned dry powder is mixed mechanically for a time of 0.1h to 6h (e.g., 0.1h, 1h, 2h, 3h, 4h, 5h, 6h, or any range between the two), thereby ensuring uniform mixing of the polymer matrix and the lithium salt. More preferably, the mixing time is 0.5h to 3h.

[0044] According to some specific embodiments of this application, the melt extrusion temperature of the first twin-screw extruder is 50°C to 300°C (for example, it can be 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, or any range between the two), the screw speed is 10 r / min to 200 r / min (for example, it can be 10 r / min, 50 r / min, 75 r / min, 100 r / min, 125 r / min, 150 r / min, 175 r / min, 200 r / min, or any range between the two), and the cooling and setting temperature is 5°C to 25°C (for example, it can be 5°C, 10°C, 15°C, 20°C, 25°C, or any range between the two). Therefore, the polymer electrolyte can be further pre-lithiated.

[0045] S200: Lithified polymer electrolyte particles, a first inorganic solid electrolyte, and a second inorganic solid electrolyte are mixed and stirred, heated and sheared to form a second molten slurry, which is then extruded and cast into a film, cooled and shaped to obtain a composite solid electrolyte membrane.

[0046] In this step, lithiated polymer electrolyte particles, a first inorganic solid electrolyte, and a second inorganic solid electrolyte are mixed and thoroughly mixed under specific temperature and stirring conditions. The mixture is then heated and melted using a second twin-screw extruder, and sheared to obtain a melt mixture. This melt is then cast into a film through an extruder die, and the cast film is directly cooled and shaped to obtain the composite solid electrolyte membrane. Therefore, the dry melt casting process can achieve uniform composite formation of lithiated polymer electrolyte, a first inorganic solid electrolyte, and a second inorganic solid electrolyte under solvent-free conditions, avoiding interfacial side reactions and porosity defects. The combined casting-hot pressing process enables low-cost, large-scale production. Furthermore, the high-speed shear-induced lithiation of the polymer electrolyte system forms a coarse fiber network, whose three-dimensional interconnected structure enhances the mechanical strength of the solid electrolyte membrane while facilitating lithium-ion transport.

[0047] In some specific embodiments, the mixing temperature is 20°C to 60°C (e.g., 20°C, 30°C, 40°C, 50°C, 60°C, or any range between these two), and the mixing time is 0.1h to 6h (e.g., 0.1h, 1h, 2h, 3h, 4h, 5h, 6h, or any range between these two), thereby ensuring uniform mixing of the lithium-ionized polymer electrolyte, the first inorganic solid electrolyte, and the second inorganic solid electrolyte. More preferably, the mixing time is 0.5h to 3h.

[0048] According to some specific embodiments of this application, the melt extrusion temperature of the second twin-screw extruder is 100℃~250℃ (for example, it can be 100℃, 120℃, 140℃, 160℃, 180℃, 200℃, 220℃, 250℃ or any range between the two), and the screw speed is 10r / min~200r / min (for example, it can be 10r / min, 50r / min, 70r / min, 100r / min, 120r / min, 150r / min). The speed range is 180 r / min, 200 r / min, or any range between two of these values. The cooling and setting temperature is 5℃~25℃ (e.g., 5℃, 10℃, 15℃, 20℃, 25℃, or any range between two of these values), and the traction speed is 0.1 m / min~1 m / min (e.g., 0.1 m / min, 0.2 m / min, 0.4 m / min, 0.6 m / min, 0.8 m / min, 1 m / min, or any range between two of these values). This further ensures the uniform composite of the lithiated polymer electrolyte, the first inorganic solid electrolyte, and the second inorganic solid electrolyte under solvent-free conditions, avoiding interfacial side reactions and porosity defects. Furthermore, it further ensures that the lithiated polymer electrolyte system forms a coarse fiber network, whose three-dimensional interconnected structure enhances the mechanical strength of the solid electrolyte membrane while facilitating lithium-ion transport.

[0049] Furthermore, the above method also includes: S300: The composite solid electrolyte membrane obtained in step S200 is subjected to multi-stage hot pressing under certain temperature and pressure to reduce it to the required thickness.

[0050] In some specific embodiments, the hot pressing temperature is 50℃~200℃ and the pressure is 2MPa~20MPa.

[0051] As some specific embodiments, the processes of steps S100 to S300 described above must be carried out in a glove box or dew point room.

[0052] The method for preparing composite solid electrolyte membranes according to the above embodiments of this application utilizes a dry melt casting process to achieve uniform composite formation of a lithiated polymer electrolyte, a first inorganic solid electrolyte, and a second inorganic solid electrolyte under solvent-free conditions, effectively avoiding interfacial side reactions and porosity defects. Furthermore, the combined casting-hot pressing process enables low-cost, large-scale production. In addition, this method employs a high-speed shear-induced lithiation polymer electrolyte system to form a coarse fiber network; its three-dimensional interconnected structure enhances the mechanical strength of the solid electrolyte membrane while facilitating lithium-ion transport.

[0053] A third aspect of this application discloses a solid-state battery. According to embodiments of this application, the solid-state battery includes a composite solid-state electrolyte membrane as described in the first aspect and a composite solid-state electrolyte membrane prepared by the method of the second aspect. This facilitates the solid-state battery to possess high ionic conductivity and interfacial stability, low interfacial impedance, and excellent mechanical strength.

[0054] In some embodiments of this application, the solid-state battery includes a positive electrode, a negative electrode, and the aforementioned composite solid-state electrolyte membrane. During the charging and discharging process of the solid-state battery, active ions repeatedly insert and extract between the positive and negative electrode. The composite solid-state electrolyte membrane acts as a conductor of ions between the positive and negative electrode.

[0055] In some embodiments of this application, the negative electrode sheet includes a negative current collector and a negative active layer disposed on at least one side surface of the negative current collector. The negative active layer includes a negative active material, an optional negative conductive agent, and an optional negative adhesive.

[0056] In some embodiments of this application, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0057] In some embodiments of this application, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include at least one of elemental tin, tin oxide compounds, and tin alloys.

[0058] In some embodiments of this application, the negative electrode binder may include at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0059] In some embodiments of this application, the negative electrode conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0060] In some embodiments of this application, the negative electrode active layer may optionally include other additives, such as thickeners and plasticizers, including at least one of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, 1,3-dioxolane, 1,4-dioxane, propylene carbonate, ethylene carbonate, diethyl carbonate or dimethyl carbonate, succinate, and adiponitrile.

[0061] In a fourth aspect, this application proposes a battery pack. According to embodiments of this application, the battery pack includes a composite solid-state electrolyte membrane as described in the first aspect, a composite solid-state electrolyte membrane prepared by the method of the second aspect, or a solid-state battery as described in the third aspect. This facilitates the battery pack to possess high ionic conductivity and interfacial stability, low interfacial impedance, and excellent mechanical strength.

[0062] In some embodiments, the battery pack can be a battery module, and the number of battery cells contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0063] In some embodiments, the battery pack can be a battery module, and the number of battery modules contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0064] This application discloses an electrical device in its fifth aspect. According to embodiments of this application, the electrical device includes a composite solid-state electrolyte membrane as described in the first aspect, a composite solid-state electrolyte membrane prepared by the method of the second aspect, a solid-state battery as described in the third aspect, or a battery pack as described in the fourth aspect. The features and advantages described above for solid-state batteries also apply to this electrical device, and will not be repeated here.

[0065] Solid-state battery cells, solid-state battery modules, and solid-state battery packs can be used as power sources for electrical devices or as energy storage units for electrical devices. Electrical devices can include, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0066] As electrical equipment, solid-state battery cells, solid-state battery modules, or solid-state battery packs can be selected according to their usage requirements.

[0067] As one example, the electrical device can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the electrical device for solid-state batteries, solid-state battery packs or solid-state battery modules can be used.

[0068] Another example of the device could be a mobile phone, tablet computer, laptop computer, etc. Such devices typically require a thin and light design and can use solid-state battery cells as a power source.

[0069] It should be noted that the features and advantages described above for solid-state batteries also apply to this electrical device, and will not be repeated here.

[0070] The embodiments of this application are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. In addition, unless otherwise specified, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods. For reaction conditions not listed, they are also readily available to those skilled in the art.

[0071] Example 1 This embodiment provides a composite solid electrolyte membrane, the preparation method of which includes: Step 1: Pre-lithiation of the polymer matrix. In this embodiment, the polymer matrix is ​​an ethylene-methyl acrylate copolymer, and the lithium salt is LiTFSI. The polymer matrix and lithium salt are weighed in a glove box at a mass ratio of 85:15 and mixed at room temperature for 30 minutes to ensure uniform mixing of the dry powders. Then, the mixture is heated to 160°C using a twin-screw extruder at a speed of 50 r / min to ensure thorough mixing, melting, and shearing into a stable slurry. After extrusion through a specific extruder die, the slurry is directly cooled, shaped, and granulated. The cooling and setting temperature is 20°C.

[0072] Step 2: The lithiated polymer particles are mixed with two types of inorganic solid electrolyte powders of different particle sizes at room temperature for 1 hour until fully mixed and homogeneous. In this embodiment, the inorganic solid electrolyte is LATP, wherein the particle size D of the first inorganic solid electrolyte is... 50,A 0.5 μm, D max,A The particle size D of the second inorganic solid electrolyte is 0.9 μm. 50,B It is 1.5 μm, D max,B The thickness is 3.2 μm. The mass ratio of the polymer matrix and the second inorganic solid electrolyte to the first inorganic solid electrolyte is 15:70:15.

[0073] Step 3: The mixed material is heated and melted using a twin-screw extruder, and then sheared to obtain a mixed melt. The melt extrusion temperature is 190 ℃, and the screw speed is 50 r / min. The melt is then cast into a film through the extruder die, and the cast film is then directly cooled and shaped to obtain a composite solid electrolyte membrane with a thickness of 100 μm. The cooling and shaping temperature is 20 ℃, and the traction speed is 0.2 m / min.

[0074] Step 4: The above-mentioned composite solid electrolyte membrane is subjected to multi-stage hot pressing and thinning at 100 ℃ and 2 MPa pressure to finally obtain a high-strength composite solid electrolyte membrane with a thickness of 50 μm.

[0075] Example 2 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 2: In this embodiment, the inorganic solid electrolyte is LATP, wherein the particle size D of the first inorganic solid electrolyte is... 50,A 0.2 μm, D max,A The particle size D of the second inorganic solid electrolyte is 0.5 μm. 50,B It is 0.8 μm, D max,B It is 2.4 μm.

[0076] Example 3 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 2: In this embodiment, the inorganic solid electrolyte is LATP, wherein the particle size D of the first inorganic solid electrolyte is... 50,A 0.5 μm, D max,A The particle size D of the second inorganic solid electrolyte is 0.9 μm. 50,B It is 2.0 μm, D max,B It is 3.8 μm.

[0077] Example 4 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 1: The mass ratio of polymer matrix to lithium salt is 90:10.

[0078] Example 5 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 1: The mass ratio of polymer matrix to lithium salt is 95:5.

[0079] Example 6 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 1: The mass ratio of polymer matrix to lithium salt is 70:30.

[0080] Example 7 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 2: The mass ratio of the polymer matrix and the second inorganic solid electrolyte to the first inorganic solid electrolyte is 10:85:5.

[0081] Example 8 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 2: The mass ratio of the polymer matrix, the second inorganic solid electrolyte, and the first inorganic solid electrolyte is 30:35:35.

[0082] Example 9 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 2: In this embodiment, the inorganic solid electrolyte is Li6PS5Cl, wherein the particle size D of the first inorganic solid electrolyte is... 50,A It is 1.0 μm, D max,A The particle size D of the second inorganic solid electrolyte is 2.2 μm. 50,B It is 6.0 μm, D max,B It is 10.0 μm. Example 10 The preparation method in this embodiment is basically the same as that in Example 1, except that: Step 1: The mass ratio of polymer matrix to lithium salt is 90:10.

[0083] Step 2: In this embodiment, the inorganic solid electrolyte is Li6PS5Cl, wherein the particle size D of the first inorganic solid electrolyte is... 50,A It is 1.0 μm, D max,A The particle size D of the second inorganic solid electrolyte is 2.2 μm. 50,B It is 6.0 μm, D max,B It is 10.0 μm.

[0084] Example 11 The preparation method of this embodiment is basically the same as that of Example 9, except that: Step 2: In this embodiment, the inorganic solid electrolyte is Li6PS5Cl, wherein the particle size D of the first sulfide solid electrolyte is... 50,A 0.5 μm, D max,A The particle size D of the second sulfide solid electrolyte is 1.5 μm. 50,B It is 4.0 μm, D max,B It is 8.0 μm.

[0085] Example 12 The preparation method of this embodiment is basically the same as that of Example 9, except that: Step 2: In this embodiment, the inorganic solid electrolyte is Li6PS5Cl, wherein the particle size D of the first sulfide solid electrolyte is... 50,A It is 2.0 μm, D max,A The particle size D of the second sulfide solid electrolyte is 3.0 μm. 50,B It is 8.0 μm, D max,B It is 11.5 μm.

[0086] Example 13 This embodiment provides a composite solid electrolyte membrane, the preparation method of which includes: Step 1: Pre-lithiation of the polymer matrix. In this embodiment, the polymer matrix is ​​a hydrogenated styrene-butadiene block copolymer, and the lithium salt is LiTFSI. The polymer matrix and lithium salt are weighed in a glove box at a mass ratio of 85:15 and mixed at room temperature for 30 minutes to ensure uniform mixing of the dry powders. Then, the mixture is heated to 220°C using a twin-screw extruder at a speed of 50 r / min to ensure thorough mixing, melting, and shearing into a stable slurry. After extrusion through a specific extruder die, the slurry is directly cooled, shaped, and granulated at a cooling and setting temperature of 20°C.

[0087] Step 2: The lithiated polymer particles are mixed with two types of inorganic solid electrolyte powders of different particle sizes at room temperature for 1 hour until fully mixed and homogeneous. In this embodiment, the inorganic solid electrolyte is LATP, wherein the particle size D of the first inorganic solid electrolyte is... 50,A 0.5 μm, D max,A <1.0 μm; Particle size D of the second inorganic solid electrolyte 50,B It is 1.5 μm, D max,B <3.5 μm. The mass ratio of the polymer matrix and the second inorganic solid electrolyte to the first inorganic solid electrolyte is 20:60:20.

[0088] Step 3: The mixed material is heated and melted using a twin-screw extruder, and then sheared to obtain a mixed melt. The melt extrusion temperature is 230 ℃, and the screw speed is 50 r / min. The melt is then cast into a film through the extruder die, and the cast film is then directly cooled and shaped to obtain a composite solid electrolyte membrane with a thickness of 100 μm. The cooling and shaping temperature is 20 ℃, and the traction speed is 0.2 m / min.

[0089] Step 4: The above-mentioned composite solid electrolyte membrane is subjected to multi-stage hot pressing and thinning at 150 ℃ and 2 MPa pressure to finally obtain a high-strength composite solid electrolyte membrane with a thickness of 50 μm.

[0090] Example 14 The preparation method of this embodiment is basically the same as that of Example 13, except that: Step 1: The mass ratio of polymer matrix to lithium salt is 90:10.

[0091] Example 15 The preparation method of this embodiment is basically the same as that of Example 13, except that: Step 2: In this embodiment, the inorganic solid electrolyte is Li6PS5Cl, wherein the particle size D of the first inorganic solid electrolyte is... 50,A It is 1.0 μm, D max,A The particle size D of the second inorganic solid electrolyte is 2.2 μm. 50,B It is 6.0 μm, D max,B It is 10.0 μm.

[0092] Example 16 The preparation method of this embodiment is basically the same as that of Example 13, except that: Step 1: The mass ratio of polymer matrix to lithium salt is 90:10.

[0093] Step 2: In this embodiment, the inorganic solid electrolyte is Li6PS5Cl, wherein the particle size D of the first inorganic solid electrolyte is... 50,A It is 1.0 μm, D max,A The particle size D of the second inorganic solid electrolyte is 2.2 μm. 50,B It is 6.0 μm, D max,B It is 10.0 μm.

[0094] Comparative Example 1 The preparation method of this comparative example is basically the same as that of Example 1, except that: Step 1: The polymer matrix was not pre-lithiated.

[0095] Step 2: Particle size distribution of the inorganic solid electrolyte was not performed. In this comparative example, the inorganic solid electrolyte is LATP, and the particle size D of the LATP solid electrolyte is... 50 1.0 μm, D max The thickness is 2.7 μm. The mass ratio of the polymer matrix to the inorganic solid electrolyte LATP is 15:85.

[0096] Comparative Example 2 The preparation method of this comparative example is basically the same as that of Example 1, except that: Step 1: The polymer matrix was not pre-lithiated.

[0097] Comparative Example 3 The preparation method of this comparative example is basically the same as that of Example 1, except that: Step 1: The polymer matrix was not pre-lithiated.

[0098] Step 2: Particle size distribution of the inorganic solid electrolyte was not performed. In this comparative example, the inorganic solid electrolyte is Li6PS5Cl, and the particle size D of the Li6PS5Cl solid electrolyte is... 50 It is 6.0 μm, D max The thickness is 10.0 μm. The mass ratio of the polymer matrix to the inorganic solid electrolyte Li6PS5Cl is 15:85.

[0099] Comparative Example 4 Step 2: Particle size distribution of the inorganic solid electrolyte was not performed. In this comparative example, the inorganic solid electrolyte is Li6PS5Cl, and the particle size D of the Li6PS5Cl solid electrolyte is... 50 It is 6.0 μm, D max It is 10.0 μm.

[0100] Unlithiated polymer matrix particles and ungraded inorganic solid electrolyte powder were mixed at room temperature for 1 hour until fully mixed and homogeneous. The mixture was then directly subjected to screw melt extrusion-casting-hot pressing.

[0101] The parameters of the above embodiments and comparative examples are shown in Table 1.

[0102] Table 1

[0103] Test example: 1) Thickness Thickness testing was performed using a Maer thickness gauge in accordance with national standard GB / T 6672-2001 and ISO 4593:1993.

[0104] 2) Particle size statistics Offline statistical analysis—SEM / image method—was employed. In an argon-atmospheric glove box (H2O < 0.1 ppm, O2 < 1 ppm), a small amount of inorganic solid electrolyte powder was uniformly dispersed in a strictly dehydrated inert solvent. A drop of the dispersion was placed on a clean silicon wafer or aluminum foil, and the solvent was allowed to evaporate completely within the glove box, leaving dispersed particles, which were then attached to the SEM sample stage. The sample was then transferred from the glove box to the SEM or FIB-SEM (Focused Ion Beam Scanning Electron Microscopy) chamber using a dedicated transfer rod or vacuum transport box, avoiding contact with air. Multiple SEM or cross-sectional SEM images were captured at different magnifications to ensure statistical randomness and representativeness. Particle size statistics were performed using image analysis software (ImageJ, Nano Measurer, etc.), which generated a list of all measured particle sizes. Based on this list, a quantity-particle size distribution histogram and a cumulative distribution curve were plotted. The D-value was directly read from the cumulative distribution curve. 10 D 50 D 90 Dmax Equivalent (Note: This D) 50 Based on the quantity D 50 ).

[0105] 3) Cross-sectional morphology In an argon-atmospheric glove box (H2O < 0.1 ppm, O2 < 1 ppm), a composite solid electrolyte membrane measuring approximately 0.6 mm × 0.6 mm was cut and fixed onto a sample stage coated with conductive adhesive. The sample was then transferred from the glove box to the FIB-SEM (Focused Ion Beam Scanning Electron Microscopy) chamber using a dedicated transfer rod or vacuum transport box, avoiding contact with air. A cross-section of the composite solid electrolyte membrane was cut using a FIB system with a gallium ion beam as the emission source, and the microstructure and solid electrolyte particle distribution were observed using SEM. Simultaneously, EDS-mapping can be used to further analyze the elemental distribution of the composite solid electrolyte membrane cross-section.

[0106] 4) Tensile strength The composite solid electrolyte membrane was cut into 10mm × 100mm sample strips, and tensile tests were performed on them along the length of the strips. The clamping distance was set to 40mm, and the tensile rate was 50mm / min. Three strips were prepared for each sample, and the final result was the average value. The calculation formula is: tensile strength σ = F / S, where F is the maximum force that the sample can withstand when it breaks, and S is the original cross-sectional area.

[0107] 5) Ionic conductivity Electrochemical impedance spectroscopy (EIS) of the composite solid electrolyte membrane was obtained using the AC impedance method, and the ionic conductivity of the composite solid electrolyte membrane was calculated from this. The specific operation steps were as follows: the composite solid electrolyte membrane was cut into circular samples with a diameter of 10 mm using a cutting machine, and assembled into a clamp battery of stainless steel sheet (SS) / solid electrolyte membrane / stainless steel sheet (SS) system in an argon atmosphere glove box (H2O<0.1ppm, O2<1ppm).

[0108] AC impedance testing was performed at room temperature using an electrochemical workstation. A two-electrode system was used, with the test voltage set to 0V, the scanning frequency range of 0.1Hz to 1MHz, and the amplitude of 10mV. The bulk impedance of the composite solid electrolyte membrane was calculated based on the intersection of the high-frequency line and the real axis in the impedance spectrum. The ionic conductivity σ was then calculated using the formula: σ = d / (R•S), where d is the thickness of the composite solid electrolyte membrane (µm), and S is the effective area of ​​the composite solid electrolyte membrane (0.785cm²). 2 R is the bulk impedance (Ω) of the composite solid electrolyte membrane. Measure three or more parallel samples and calculate the average value.

[0109] 6) Electronic conductivity: The mold battery was assembled according to the method for testing ionic conductivity.

[0110] At room temperature, constant voltage polarization was performed using an electrochemical workstation (E1=0.2V, 30min; E2=0.1V, 30min). The resistance was calculated using DC current and voltage drop, and then the conductivity was calculated.

[0111] Calculation method: R'=(E2-E1) / (I2-I1), electronic conductivity σ e- =d / (R'•S), where d is the thickness of the composite solid electrolyte membrane (µm), and S is the effective area of ​​the composite solid electrolyte membrane (0.785cm²). 2 Let E be the steady-state voltage, I be the steady-state current, and R' be the steady-state resistance (Ω). Measure three or more parallel samples and calculate the average value.

[0112] The test results are shown in Table 2 below.

[0113] Table 2

[0114] As shown in Table 2 above, comparing Examples 1-16 and Comparative Examples 1-4, the solid electrolyte membrane provided in this application exhibits excellent mechanical strength and ionic conductivity. By employing multi-scale particle gradation of the inorganic solid electrolyte, large particles construct the framework to reduce interfacial impedance, while small particles fill the gaps to enhance bulk conductivity, effectively reducing interfacial impedance. Simultaneously, the addition of dissociable lithium salts increases the lithium-ion conduction network in the polymer electrolyte, and the polymer electrolyte uniformly coats at least a portion of the surface of the inorganic solid electrolyte, resulting in a solid electrolyte membrane with good flexibility and ion conduction properties, further reducing interfacial impedance. Furthermore, the use of a high-speed shear-induced lithiation polymer electrolyte system to form a coarse fiber network, retaining a three-dimensional interconnected structure, enhances the mechanical strength of the solid electrolyte membrane while facilitating lithium-ion transport. All these factors contribute to improving the mechanical strength and electrochemical performance of the solid electrolyte membrane.

[0115] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0116] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A composite solid electrolyte membrane, characterized in that, include: An inorganic solid electrolyte, comprising a first inorganic solid electrolyte and a second inorganic solid electrolyte, wherein the particle size D of the first inorganic solid electrolyte is... 50,A The particle size D is smaller than that of the second inorganic solid electrolyte. 50,B ; A polymer electrolyte comprising a polymer matrix and a lithium salt, wherein the lithium salt is doped in the polymer matrix, and the polymer electrolyte is coated on at least a portion of the surface of the inorganic solid electrolyte in the form of a fibrous network.

2. The composite solid electrolyte membrane according to claim 1, characterized in that, The inorganic solid electrolyte includes at least one of oxide solid electrolyte, sulfide solid electrolyte, and halide solid electrolyte.

3. The composite solid electrolyte membrane according to claim 2, characterized in that, The oxide solid electrolyte includes a first oxide solid electrolyte and a second oxide solid electrolyte, wherein the particle size D of the first oxide solid electrolyte is... 50,A The particle size is 0.2µm~0.5µm, and the maximum particle size D of the first oxide solid electrolyte is... max,A <1.0µm; the particle size D of the second oxide solid electrolyte 50,B The particle size ranges from 0.8µm to 2.0µm, and the maximum particle size D of the second oxide solid electrolyte is... max,B <4.0µm.

4. The composite solid electrolyte membrane according to claim 2, characterized in that, The sulfide solid electrolyte includes a first sulfide solid electrolyte and a second sulfide solid electrolyte, wherein the particle size D of the first sulfide solid electrolyte is... 50,A The particle size ranges from 0.5µm to 2.0µm, and the maximum particle size D of the first sulfide solid electrolyte is... max,A <3.5µm; the particle size D of the second sulfide solid electrolyte 50,B The particle size ranges from 4.0 µm to 8.0 µm, and the maximum particle size D of the second sulfide solid electrolyte is... max,B <12µm.

5. The composite solid electrolyte membrane according to claim 1, characterized in that, The particle size distribution uniformity index K1 of the first inorganic solid electrolyte is 0.9~1.2; And / or, the particle size distribution uniformity index K2 of the second inorganic solid electrolyte is 0.8~1.

3.

6. The composite solid electrolyte membrane according to claim 1, characterized in that, The mass ratio of the second inorganic solid electrolyte to the first inorganic solid electrolyte is (85:5) to (35:35). And / or, the mass ratio of the polymer matrix, the second inorganic solid electrolyte, and the first inorganic solid electrolyte is (10:85:5) to (30:35:35). And / or, the mass ratio of the polymer matrix to the lithium salt is (95:5) to (70:30).

7. The composite solid electrolyte membrane according to claim 2, characterized in that, The oxide solid electrolyte includes at least one of LATP, LAGP, LLZO, and LLZTO; And / or, the sulfide solid electrolyte includes at least one of LPSX1 and LM1PS, wherein X1 is selected from at least one of halogen elements and M1 is selected from at least one of Group IVA elements; And / or, the halide solid electrolyte includes at least one of the ternary compounds Li-M2-X2, wherein X2 is selected from at least one halogen element and M2 is selected from at least one element of Group IIIA and Group IIIB.

8. The composite solid electrolyte membrane according to any one of claims 1 to 7, characterized in that, The polymer matrix includes at least one of the following: ethylene-methyl acrylate copolymer, styrene-butadiene-styrene front copolymer, hydrogenated styrene-butadiene block copolymer, polyurethane, polyamide, polyimide, styrene-butadiene rubber, hydrogenated nitrile rubber, acrylonitrile-butadiene-styrene copolymer, polybutyl acrylate, polyethylene terephthalate, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, polymethyl methacrylate, and cellulose polymers.

9. The composite solid electrolyte membrane according to any one of claims 1 to 7, characterized in that, The lithium salt includes at least one of LiFSI, LiTFSI, LiClO4, and LiPF6.

10. A method for preparing a composite solid electrolyte membrane according to any one of claims 1 to 9, characterized in that, include: The polymer matrix and lithium salt are mixed, heated and sheared to form a first molten slurry, which is then extruded, cooled and shaped, and granulated to obtain lithium-ionized polymer electrolyte particles. The lithium-ionized polymer electrolyte particles, the first inorganic solid electrolyte, and the second inorganic solid electrolyte are mixed, heated and sheared to form a second molten slurry, which is then extruded and cast into a film, cooled and shaped to obtain a composite solid electrolyte membrane.

11. The method according to claim 10, characterized in that, The mixture of the polymer matrix and the lithium salt is heated and sheared using a first twin-screw extruder to form the first molten slurry, which is then extruded. And / or, a second twin-screw extruder is used to heat and shear the mixture of the lithium-ion polymer electrolyte particles, the first inorganic solid electrolyte, and the second inorganic solid electrolyte to form the second molten slurry, which is then extruded and cast into a film.

12. The method according to claim 11, characterized in that, The first twin-screw extruder has a melt extrusion temperature of 50℃~300℃, a screw speed of 10r / min~200r / min, and a cooling and setting temperature of 5℃~25℃; And / or, the melt extrusion temperature of the second twin-screw extruder is 100℃~250℃, the screw speed is 10r / min~200r / min, the cooling and setting temperature is 5℃~25℃, and the traction speed is 0.1m / min~1m / min.

13. A solid-state battery, characterized in that, It includes the composite solid electrolyte membrane according to any one of claims 1 to 9, and the composite solid electrolyte membrane prepared by the method according to any one of claims 10 to 12.

14. A battery pack, characterized in that, It includes the composite solid electrolyte membrane according to any one of claims 1 to 9, the composite solid electrolyte membrane prepared by the method according to any one of claims 10 to 12, or the solid battery according to claim 13.

15. An electrical appliance, characterized in that, It includes the composite solid electrolyte membrane according to any one of claims 1 to 9, the composite solid electrolyte membrane prepared by the method according to any one of claims 10 to 12, the solid battery according to claim 13, or the battery pack according to claim 14.

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