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CN-122025746-A - Rigid-flexible composite solid electrolyte material, preparation method and application

CN122025746ACN 122025746 ACN122025746 ACN 122025746ACN-122025746-A

Abstract

The invention discloses a rigid and flexible synergistic composite solid electrolyte, a preparation method and application thereof, and belongs to the technical field of solid batteries. Aiming at the problems that the mechanical property and the electrochemical property of the existing solid electrolyte are difficult to be compatible, the interface contact is poor and the ionic conductivity is insufficient, the material is formed by in-situ polymerization of a composite solid electrolyte base film through electrolyte, the composite solid electrolyte base film consists of a solid phase component and an organic solvent, wherein the solid phase component accounts for 10% -40% of the total mass of the material, the organic solvent accounts for 60% -90% of the total mass of the material, and the solid phase component consists of 32% -52% of a polymer matrix, 3% -13% of inorganic solid electrolyte powder, 11% -25% of a plasticizer and 30% -42% of lithium salt. The invention obviously improves the ionic conductivity and mechanical strength of electrolyte by the synergistic effect of the rigid ceramic filler, the flexible polymer matrix and the plasticizer, has flexible and controllable process, and has excellent cycle stability (such as 95.5 percent of capacity retention rate of 500 circles).

Inventors

  • ZHU WEN
  • QIU PENGYUAN

Assignees

  • 武汉睿意新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (8)

  1. 1. A hardness-softness-combination composite solid electrolyte material is characterized by being formed by in-situ polymerization of a composite solid electrolyte base film through electrolyte, wherein the composite solid electrolyte base film comprises 10% -40% of solid phase components and 60% -90% of organic solvents, the solid phase components comprise 32% -52% of polymer matrixes, 3% -13% of inorganic solid electrolyte powder, 11% -25% of plasticizers and 30% -42% of lithium salts.
  2. 2. The hardness-softness-combination composite solid electrolyte material according to claim 1, wherein the inorganic solid electrolyte powder is one or a mixture of more than two of lithium lanthanum zirconium oxide, lithium aluminum lanthanum zirconium oxide, lithium lanthanum niobium zirconium oxide, lithium lanthanum titanium zirconium oxide, lithium aluminum titanium phosphate, lithium aluminum germanium phosphate, lithium lanthanum titanate or sulfide-based electrolyte.
  3. 3. The composite solid electrolyte material of claim 1, wherein the organic solvent is one or more of N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, acetone, tetrahydrofuran, cyclopentanone, and 2-methyltetrahydrofuran-3-one.
  4. 4. The composite solid electrolyte material of claim 1, wherein the polymer matrix is one or more of polyethylene oxide, polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, polyacrylonitrile, polydimethylsiloxane, polypropylene carbonate, thermoplastic polyurethane or cellulose acetate.
  5. 5. The composite solid electrolyte material of claim 1, wherein the plasticizer is one or more of ethylene carbonate, propylene carbonate, succinonitrile, bis (2-methoxyethyl) ether or polyethylene glycol diacrylate.
  6. 6. The composite solid electrolyte material of claim 1, wherein the lithium salt is one or more of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bistrifluoromethylsulfonimide, lithium difluorosulfonylimide, lithium dioxaoxalato borate, lithium difluorooxalato borate, and lithium fluoroborate sulfite.
  7. 7. A method of preparing the rigid-flexible composite solid electrolyte material of any of claims 1 to 6, comprising the steps of: (1) Adding inorganic solid electrolyte powder into an organic solvent, and magnetically stirring at normal temperature for 20-60 min until a uniform suspension is formed; (2) Adding a polymer matrix and a plasticizer into the suspension, and continuously magnetically stirring for 2-12 hours at 40-80 ℃ until the system is completely dissolved; (3) Spreading the slurry on a clean glass plate, controlling the thickness of a wet film to be 50-1000 mu m by adopting an adjustable scraper, and drying in a vacuum drying oven at 30-150 ℃ for 6-48 hours until the mass is constant to obtain a composite solid electrolyte base film; (4) And (3) dripping the electrolyte with the in-situ polymerization function on the surface of the composite solid electrolyte base film, or soaking the surface of the solid electrolyte base film by adopting electrolyte, fully soaking, and then preserving the heat for 2-48 hours at 40-100 ℃ to initiate in-situ polymerization reaction to form the composite solid electrolyte film.
  8. 8. The method for preparing the rigid-flexible composite solid electrolyte material according to claim 7, wherein the electrolyte with the in-situ polymerization function is a vinylene carbonate/azodiisobutyronitrile system electrolyte, the electrolyte uses vinylene carbonate as a reactive solvent and azodiisobutyronitrile as an initiator, the lithium salt is one or a mixture of more than two of LiPF 6 、LiFSI、LiTFSI、LiBF 4 、LiClO 4 、LiBF 2 SO 4 and LiBOB, the mass ratio of the VC to the lithium salt is 1 (0.5-2), the mass ratio of the solvent to the initiator is 1:0.005-0.02, and the initiation condition is that the electrolyte is heated to 40-100 ℃ and kept for 2-12 h.

Description

Rigid-flexible composite solid electrolyte material, preparation method and application Technical Field The invention belongs to the technical field of solid electrolyte materials and all-solid-state batteries, and particularly relates to a composite solid electrolyte with a polymer as a matrix, a preparation method thereof, an application method of an in-situ polymerization technology and application of the electrolyte in all-solid-state lithium ion batteries. Background With the rapid development of portable electronic devices and new energy automobiles, the market demands for high-energy density and high-safety batteries are increasingly urgent. The safety of the existing liquid lithium ion battery faces serious challenges due to the leakage, combustibility and thermal runaway risks of the electrolyte, and an all-solid-state battery becomes the core direction for solving the problem. The solid electrolyte is mainly divided into an inorganic solid electrolyte and a polymer electrolyte, wherein the inorganic electrolyte has excellent mechanical property, can inhibit lithium dendrite, but has poor interface contact and large brittleness, and the polymer electrolyte has good flexibility and good interface suitability, but has low room-temperature ionic conductivity, poor mechanical strength and insufficient electrochemical stability. The existing composite solid electrolyte has the problems of poor component cooperativity, low ion transmission efficiency and high interface impedance, and the common polymer matrix (such as PEO and PVDF) is difficult to meet the high performance requirement. In addition, the existing all-solid-state battery often relies on a small amount of liquid electrolyte to improve interface contact, so that the improvement of safety and cycle stability is limited, and development of a composite solid-state electrolyte system with excellent comprehensive performance is needed. Disclosure of Invention Aiming at the problems that the mechanical property and the electrochemical property of the existing solid electrolyte are difficult to be compatible, the interface contact is poor, the ionic conductivity is insufficient and the like, the invention provides a rigid-flexible composite solid electrolyte material, a preparation method and application thereof, and the cooperative optimization of mechanical strength, ion transmission efficiency and interface compatibility is realized, so that the cycle stability and multiplying power performance of an all-solid-state battery are improved. In addition, the interface contact problem between the electrode and the electrolyte is solved by combining an in-situ polymerization technology, so that the interface resistance is effectively reduced. The composite solid electrolyte material is prepared by in-situ polymerization of a composite solid electrolyte base film through electrolyte, wherein the composite solid electrolyte base film consists of 10% -40% of solid phase components and 60% -90% of organic solvents by mass, and the solid phase components consist of 32% -52% of polymer matrix, 3% -13% of inorganic solid electrolyte powder, 11% -25% of plasticizers and 30% -42% of lithium salts by mass. Further, the inorganic solid electrolyte powder is one or a mixture of two or more of Lithium Lanthanum Zirconium Oxide (LLZO), lithium Aluminum Lanthanum Zirconium Oxide (LALZO), lithium lanthanum niobium zirconium oxide (LLZNO), lithium lanthanum titanium zirconium oxide (LLZTO), lithium Aluminum Titanium Phosphate (LATP), lithium Aluminum Germanium Phosphate (LAGP), lithium Lanthanum Titanate (LLTO) or sulfide-based electrolyte. Further, the organic solvent is one or a mixture of more than two of N-methyl pyrrolidone (NMP), N-Dimethylformamide (DMF), N-Dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), acetone, tetrahydrofuran, cyclopentanone and 2-methyltetrahydrofuran-3-one (dihydro-L-glucosone). Further, the polymer matrix is one or a mixture of more than two of polyethylene oxide (PEO), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polydimethylsiloxane (PDMS), polypropylene carbonate (PPC), thermoplastic Polyurethane (TPU) or Cellulose Acetate (CA). Further, the plasticizer is one or a mixture of more than two of Ethylene Carbonate (EC), propylene Carbonate (PC), succinonitrile (SN), bis (2-methoxyethyl) ether (PEGDME) or polyethylene glycol diacrylate (PEGDA). Further, the lithium salt is one or a mixture of two or more of lithium hexafluorophosphate (LiPF 6), lithium perchlorate (LiClO 4), lithium tetrafluoroborate (LiBF 4), lithium hexafluoroarsenate (LiAsF 6), lithium bistrifluoro-methanesulfonimide (LiTFSI), lithium difluorosulfimide (LiFSI), lithium dioxalate borate (LiBOB), lithium difluorooxalato borate (lipfob), or lithium fluoroborate sulfite (LiBF 2SO3 F). A method of preparing a rigid-flexible composite solid electrolyte material according to any one of the preced