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CN-121983643-A - Composite solid electrolyte membrane, preparation method thereof, solid battery, battery pack and electric equipment

CN121983643ACN 121983643 ACN121983643 ACN 121983643ACN-121983643-A

Abstract

The application particularly discloses a composite solid electrolyte membrane and a preparation method thereof, a solid battery, a battery pack and electric equipment, wherein the composite solid electrolyte membrane comprises an inorganic solid electrolyte, the inorganic solid electrolyte comprises a first inorganic solid electrolyte with small particles and a second inorganic solid electrolyte with large particles, the polymer electrolyte comprises a polymer matrix and lithium salt, the lithium salt is doped in the polymer matrix, and the polymer electrolyte is coated on at least part of the surface of the inorganic solid electrolyte in a fiber network mode. According to the application, the ionic conductivity and the mechanical strength of the composite solid electrolyte membrane can be effectively improved by carrying out multi-scale particle grading on the inorganic solid electrolyte and wrapping at least part of the surface of the inorganic solid electrolyte by the lithiated polymer electrolyte in the form of a coarse fiber network.

Inventors

  • ZHANG QIAN
  • TANG CHENGYU
  • XU JUNTAO

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20251028

Claims (15)

  1. 1. A composite solid electrolyte membrane comprising: An inorganic solid state electrolyte comprising a first inorganic solid state electrolyte and a second inorganic solid state electrolyte, the first inorganic solid state electrolyte having a particle size D 50,A that is less than the particle size D 50,B of the second inorganic solid state electrolyte; The polymer electrolyte comprises a polymer matrix and lithium salt, wherein the lithium salt is doped in the polymer matrix, and the polymer electrolyte is coated on at least part of the surface of the inorganic solid electrolyte in a fiber network mode.
  2. 2. The composite solid electrolyte membrane of claim 1 wherein the inorganic solid electrolyte comprises at least one of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.
  3. 3. The composite solid electrolyte membrane according to claim 2, wherein the oxide solid electrolyte comprises a first oxide solid electrolyte and a second oxide solid electrolyte, the first oxide solid electrolyte having a particle diameter D 50,A of 0.2 μm to 0.5 μm and a maximum particle diameter D max,A <1.0 μm, the second oxide solid electrolyte having a particle diameter D 50,B of 0.8 μm to 2.0 μm and a maximum particle diameter D max,B <4.0 μm.
  4. 4. The composite solid electrolyte membrane of claim 2, wherein the sulfide solid electrolyte comprises a first sulfide solid electrolyte and a second sulfide solid electrolyte, the first sulfide solid electrolyte having a particle size D 50,A to 2.0 μm and a maximum particle size D max,A <3.5 μm, the second sulfide solid electrolyte having a particle size D 50,B of 4.0 to 8.0 μm and a maximum particle size D max,B <12 μm.
  5. 5. The composite solid electrolyte membrane according to claim 1, wherein the particle size distribution uniformity index K 1 of the first inorganic solid electrolyte is 0.9 to 1.2; And/or the particle size distribution uniformity index K 2 of the second inorganic solid electrolyte is 0.8-1.3.
  6. 6. The composite solid electrolyte membrane according to claim 1, wherein a mass ratio of the second inorganic solid electrolyte to the first inorganic solid electrolyte is (85:5) - (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) - (30:35:35); and/or the mass ratio of the polymer matrix to the lithium salt is (95:5) - (70:30).
  7. 7. The composite solid electrolyte membrane of claim 2 wherein the oxide solid electrolyte comprises at least one of LATP, LAGP, LLZO, LLZTO; And/or the sulfide solid state electrolyte comprises at least one of LPSX 1 and LM 1 PS, wherein X 1 is selected from at least one of halogen elements, and M 1 is selected from at least one of group IVA elements; And/or the halide solid electrolyte comprises at least one of Li-M 2 -X 2 ternary compounds, wherein X 2 is selected from at least one of halogen elements, and M 2 is selected from at least one of group IIIA and IIIB elements.
  8. 8. The composite solid electrolyte membrane according to any one of claims 1 to 7, wherein the polymer matrix comprises at least one of an ethylene-methyl acrylate copolymer, a styrene-butadiene-styrene pre-block copolymer, a hydrogenated styrene-butadiene block copolymer, polyurethane, polyamide, polyimide, styrene-butadiene rubber, a hydrogenated nitrile rubber, an acrylonitrile-butadiene-styrene copolymer, polybutyl acrylate, polyethylene terephthalate, polyvinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, polymethyl methacrylate, cellulose-based polymer.
  9. 9. The composite solid electrolyte membrane according to any one of claims 1 to 7, wherein the lithium salt comprises at least one of LiFSI, liTFSI, liClO 4 and LiPF 6 .
  10. 10. A method of preparing the composite solid electrolyte membrane of any one of claims 1 to 9, comprising: Mixing a polymer matrix with lithium salt, heating and shearing to form first molten slurry, extruding, cooling and forming, and granulating to obtain lithiated polymer electrolyte particles; And mixing the lithiated polymer electrolyte particles, the first inorganic solid electrolyte and the second inorganic solid electrolyte, heating and shearing to form second molten slurry, extruding and casting to form a film, and cooling and forming to obtain the composite solid electrolyte membrane.
  11. 11. The method of claim 10, wherein the mixture of the polymer matrix and the lithium salt is sheared by heating using a first twin screw extruder to form the first molten slurry and extruded; and/or, heating and shearing the mixture of the lithiated polymer electrolyte particles, the first inorganic solid state electrolyte and the second inorganic solid state electrolyte by using a second double-screw extruder to form the second molten slurry, and extruding and tape-casting the second molten slurry into a film.
  12. 12. The method according to claim 11, wherein the melt extrusion temperature of the first twin-screw extruder is 50 ℃ to 300 ℃, the screw rotation speed is 10r/min to 200r/min, and the cooling shaping temperature is 5 ℃ to 25 ℃; And/or the melt extrusion temperature of the second double-screw extruder is 100-250 ℃, the screw rotating speed is 10-200 r/min, the cooling shaping temperature is 5-25 ℃, and the traction speed is 0.1-1 m/min.
  13. 13. A solid state battery comprising the composite solid state electrolyte membrane according to any one of claims 1 to 9, and the composite solid state electrolyte membrane produced by the method according to any one of claims 10 to 12.
  14. 14. A battery pack comprising the composite solid electrolyte membrane according to any one of claims 1 to 9, the composite solid electrolyte membrane produced by the method according to any one of claims 10 to 12, or the solid battery according to claim 13.
  15. 15. An electrical device, comprising the composite solid electrolyte membrane according to any one of claims 1 to 9, the composite solid electrolyte membrane produced 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.

Description

Composite solid electrolyte membrane, preparation method thereof, solid battery, battery pack and electric equipment Technical Field The application belongs to the field of solid-state batteries, and particularly relates to a composite solid-state electrolyte membrane, a preparation method thereof, a solid-state battery, a battery pack and electric equipment. Background With the proliferation of high energy density, high safety energy storage demands, all-solid-state lithium batteries are considered as the core direction of next-generation battery technology. As a core component of the solid-state battery, the solid-state electrolyte membrane needs to have high ionic conductivity, low interface resistance, and excellent machinability. The current mainstream technical routes include inorganic ceramic electrolyte, polymer electrolyte and organic-inorganic composite electrolyte, but all have significant technical bottlenecks, and are mainly represented by (1) a single inorganic electrolyte system, namely, a sintered ceramic electrolyte has high ionic conductivity, but a rigid interface leads to a low electrode/electrolyte contact area (< 60%), and interface impedance is as high as 10 3Ω·cm2 orders of magnitude. Meanwhile, the brittle characteristic (fracture toughness <2 MPa.m 1/2) causes that the film thickness is difficult to be reduced below 50 mu m, and the volume energy density of the solid-state battery is seriously restricted. (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. Plasticizer doping can increase its conductivity, but sacrifices its mechanical strength (tensile strength <1 MPa) and thermal stability deteriorates. (3) The traditional organic-inorganic composite electrolyte is characterized in that solvent residues are introduced in a wet process, side reactions are easy to cause, micro cracks are caused by drying shrinkage, single-particle-size fillers are easy to form local aggregation, inorganic fillers are randomly distributed, and continuous ion channels cannot be formed. Therefore, the existing solid electrolyte membrane has the problems of low ionic conductivity, poor mechanical strength and the like. Disclosure of Invention The present application aims to solve at least one of the technical problems in the related art to some extent. To this end, an object of the present application is to propose a composite solid electrolyte membrane and a method for its preparation, a solid battery, a battery pack and an electrical apparatus. According to the application, the ionic conductivity and the mechanical strength of the composite solid electrolyte membrane can be effectively improved by carrying out multi-scale particle grading on the inorganic solid electrolyte and wrapping at least part of the surface of the inorganic solid electrolyte by the lithiated polymer electrolyte in the form of a coarse fiber network. The first aspect of the present application proposes a composite solid electrolyte membrane. According to an embodiment of the present application, the composite solid electrolyte membrane includes: An inorganic solid state electrolyte comprising a first inorganic solid state electrolyte and a second inorganic solid state electrolyte, the first inorganic solid state electrolyte having a particle size D 50,A that is less than the particle size D 50,B of the second inorganic solid state electrolyte; The polymer electrolyte comprises a polymer matrix and lithium salt, wherein the lithium salt is doped in the polymer matrix, and the polymer electrolyte is coated on at least part of the surface of the inorganic solid electrolyte in a fiber network mode. According to the composite solid electrolyte membrane provided by the embodiment of the application, the multi-scale particle grading is carried out on the inorganic solid electrolyte, so that the bulk conductivity of the composite solid electrolyte membrane can be synchronously improved to be in contact with an interface, and the interface impedance is reduced. Meanwhile, the polymer electrolyte is wrapped on at least part of the surface of the inorganic solid electrolyte, so that the flexibility of the composite solid electrolyte membrane can be effectively improved, and the ion conductivity of the polymer electrolyte can be improved by doping lithium salt in the polymer electrolyte. In addition, the polymer electrolyte is coated on at least part of the surface of the inorganic solid electrolyte in the form of a coarse fiber network, so that the mechanical strength of the composite solid electrolyte membrane can be enhanced, and the lithium ion transmission can be facilitated. In addition, the composite solid electrolyte membrane according to the above embodiment of the application may also have the following additional technical features: In some embodiments of the application, the inorganic solid state electrolyte