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CN-121618041-B - Multilayer composite solid electrolyte membrane, preparation method and prepared solid battery

CN121618041BCN 121618041 BCN121618041 BCN 121618041BCN-121618041-B

Abstract

The invention discloses a multilayer composite solid electrolyte membrane, a preparation method and a prepared solid battery, wherein the multilayer composite solid electrolyte membrane sequentially comprises a three-dimensional polymer network solid electrolyte, a LiPON layer and a polydopamine layer, the thickness of the three-dimensional polymer network solid electrolyte is 20-40 mu m, and the thickness of the polydopamine layer is less than 100nm. According to the invention, by adopting the synergistic effect of modifying LLZO and degrading chitosan by using the silane coupling agent, a better ion transmission coordination effect can be provided, and the efficiency of an ion channel is improved. The dendrite inhibition efficiency is improved, obvious cracks are avoided after 1000 times of circulation, the dendrite inhibition method is applied to a solid-state battery, the circulation life of the battery is prolonged, and the dendrite inhibition method has a capacity retention rate of 95% after 1000 times of circulation. The mechanical toughness of the solid electrolyte is improved, and the elongation at break can reach 130%. The aqueous solvent is used in the whole preparation process, so that the use of an organic solvent is avoided, the energy consumption is reduced by 40%, and the whole preparation process has no VOC emission, and is green, safe and environment-friendly.

Inventors

  • ZHOU HUI
  • YU CHANGBO
  • ZHOU CHANGJI
  • ZHANG CHENCHUN
  • CHEN YONGLONG
  • YU BIN

Assignees

  • 浙江中科立德新材料有限公司

Dates

Publication Date
20260512
Application Date
20260130

Claims (7)

  1. 1. The multilayer composite solid electrolyte membrane is characterized by sequentially comprising a three-dimensional polymer network solid electrolyte, a LiPON layer and a polydopamine layer, wherein the thickness of the three-dimensional polymer network solid electrolyte is 20-40 mu m, and the thickness of the polydopamine layer is less than 100nm; The preparation raw materials of the three-dimensional polymer networking solid electrolyte comprise, by weight, 20-40% of polyethylene oxide, 10-30% of degradation chitosan, 20-30% of modified LLZO, 15-40% of lithium salt, 6-10% of a cross-linking agent and 100% of a solvent; the molecular weight of the degraded chitosan is 9000-11000; The cross-linking agent comprises at least one of polyethylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, glycerol polyglycidyl ether or sorbitol polyglycidyl ether; the modified LLZO is silane coupling agent modified LLZO.
  2. 2. The multilayer composite solid electrolyte membrane of claim 1, wherein the method of preparing the degraded chitosan comprises the steps of: Dissolving chitosan powder with high polymerization degree in a peroxyacid aqueous solution to form a transparent viscous solution, and continuously stirring to perform degradation reaction; after degradation, adding LiOH solution for neutralization, and filtering to remove insoluble matters; Mixing the filtrate with ethanol to form chitosan turbid liquid, and freeze-drying to obtain the degraded chitosan.
  3. 3. The multilayer composite solid electrolyte membrane of claim 2 wherein the degradation reaction conditions satisfy at least one of a-d conditions: a, the deacetylation degree of chitosan with high polymerization degree is more than 90 percent, and the molecular weight is more than 10 ten thousand; the degradation temperature is 40-60 ℃; c, degradation time is 10-20h; the mass volume ratio of the chitosan with high polymerization degree to the aqueous solution of the peroxyacid is (5-15) g to 1L.
  4. 4. The multilayer composite solid electrolyte membrane according to claim 2, wherein the preparation method of the silane coupling agent modified LLZO comprises the steps of: drying LLZO, grinding and sieving to obtain LLZO powder; dissolving a silane coupling agent in absolute ethyl alcohol, stirring and dispersing uniformly, dropwise adding an acetic acid solution, and obtaining a silane coupling agent hydrolysis solution after hydrolysis reaction; adding LLZO powder into a silane coupling agent hydrolysis solution, uniformly stirring, and carrying out modification reaction; And after the reaction is finished, carrying out suction filtration, separation, washing and drying to obtain the silane coupling agent modified LLZO.
  5. 5. The multilayer composite solid electrolyte membrane of claim 4 wherein the conditions of the modification reaction satisfy at least one of the conditions e-g: e, dropwise adding acetic acid solution, wherein the pH value is 4-5; f, the temperature of the hydrolysis reaction is 30-40 ℃ and the hydrolysis reaction time is 1-5h; g, the temperature of the modification reaction is 50-80 ℃, and the modification reaction time is 6-12h.
  6. 6. A method for producing the multilayer composite solid electrolyte membrane according to any one of claims 2 to 5, comprising the steps of: polyethylene oxide, degradation chitosan, modified LLZO, lithium salt and a cross-linking agent are dissolved in a solvent, and a three-dimensional polymer network solid electrolyte is formed by casting; magnetron sputtering deposition of a LiPON layer on the surface of the three-dimensional polymer networked solid electrolyte; and (3) carrying out hot-pressing densification on the LiPON layer, and coating a polydopamine layer on the surface to obtain the multilayer composite solid electrolyte membrane.
  7. 7. A solid state battery comprising the multilayer composite solid state electrolyte membrane of any one of claims 1-5.

Description

Multilayer composite solid electrolyte membrane, preparation method and prepared solid battery Technical Field The invention relates to the field of electrolyte materials, in particular to a multilayer composite solid electrolyte membrane, a preparation method and a prepared solid battery. Background With the development of scientific technology, solid-state batteries are considered as powerful candidates for next-generation energy storage technologies due to their high safety and high energy density. The solid-state electrolyte is the core component of the solid-state battery, and determines the ion conductivity, interfacial stability, and cycle life of the battery. The existing solid electrolyte has low ionic conductivity and insufficient mechanical strength at room temperature, has poor stability on a lithium metal negative electrode, is easy to cause growth of lithium dendrites, and causes potential safety hazards. In addition, the existing secondary battery mostly adopts organic solvents, and the preparation process is not environment-friendly and has high energy consumption, so that the development of a solid electrolyte with excellent ion conduction performance, long cycle life, green production and low energy consumption is important. Chinese patent application CN118511348a discloses a method for manufacturing a composite solid electrolyte, which can effectively improve ion conductivity of lithium ions by forming a ceramic ion conductor comprising a first polymer having a crosslinkable functional group and a ceramic compound, and can improve ion conductivity of the composite solid electrolyte by using the ceramic ion conductor, but the improvement of ion conductivity is not remarkable. Chinese patent application CN117813712a discloses a polymer solid electrolyte laminate and a method for preparing the same, comprising a protective layer formed on at least one surface of a polymer solid electrolyte, which can prevent the physical properties of the polymer solid electrolyte from being changed due to moisture and external air in a continuous process of laminating with an electrode after preparing the polymer solid electrolyte and in a process such as transportation, but its ion conductivity performance is not good. Disclosure of Invention In order to develop a solid electrolyte which is excellent in ion conduction performance, long in cycle life and low in energy consumption, and can be produced in a green manner, a first aspect of the invention provides a multilayer composite solid electrolyte membrane which is sequentially a three-dimensional polymer network solid electrolyte, a LiPON (lithium phosphorus oxygen nitrogen) layer and a polydopamine layer, wherein the thickness of the three-dimensional polymer network solid electrolyte is 20-40 mu m, the thickness of the polydopamine layer is <100nm, and the three-dimensional polymer network solid electrolyte comprises modified LLZO by taking chitosan as a framework. As an implementation mode, the preparation raw materials of the three-dimensional polymer networking solid electrolyte comprise, by weight, 20-40% of polyethylene oxide, 10-30% of degraded chitosan, 20-30% of modified LLZO, 15-40% of lithium salt, 6-10% of a cross-linking agent and 100% of a solvent. As one embodiment, the polyethylene oxide (PEO) has a number average molecular weight of 300 to 2500. As one embodiment, the molecular weight of the degraded chitosan is 9000-11000. As an embodiment, the preparation method of the degraded chitosan comprises the following steps: Dissolving chitosan powder with high polymerization degree in a peroxyacid aqueous solution to form a transparent viscous solution, and continuously stirring to perform degradation reaction; after degradation, adding LiOH solution for neutralization, and filtering to remove insoluble matters; Mixing the filtrate with ethanol to form chitosan turbid liquid, and freeze-drying to obtain the degraded chitosan. As an embodiment, the degradation reaction conditions satisfy at least one of the conditions a-d: a, the deacetylation degree of chitosan with high polymerization degree is more than 90 percent, and the molecular weight is more than 10 ten thousand; the degradation temperature is 40-60 ℃; c, degradation time is 10-20h; the mass volume ratio of the chitosan with high polymerization degree to the aqueous solution of the peroxyacid is (5-15) g to 1L. As one embodiment, the aqueous peroxyacid solution has a mass fraction of 1 to 5%. As one embodiment, the aqueous peroxyacid solution has a mass fraction of 1%. As one embodiment, the peroxyacid includes at least one of a peroxyorganic acid or a peroxyinorganic acid. As an embodiment, the peroxyacid includes at least one of peroxyformic acid, peroxyacetic acid, peroxytrifluoroacetic acid, peroxypropionic acid, peroxybutyric acid, peroxyisovaleric acid, long-chain peroxyfatty acid, peroxybenzoic acid, m-chloroperoxybenzoic acid, nitroperoxybenzoic acid, monoperoxyphthalic acid,