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CN-121983662-A - Thioether crosslinked solid polymer electrolyte membrane and preparation method and application thereof

CN121983662ACN 121983662 ACN121983662 ACN 121983662ACN-121983662-A

Abstract

The invention relates to the technical field of electrolyte, in particular to a thioether crosslinked solid polymer electrolyte membrane, a preparation method and application thereof. The preparation method comprises the steps of taking N, N-dimethylformamide, respectively adding 3, 6-dioxa-1, 8-octanedithiol and isocyanic triglycidyl uric acid, uniformly stirring to obtain a mixed solution, adding lithium bis (trifluoromethylsulfonyl) imide into the mixed solution, putting the mixed solution into a magnet to completely dissolve the mixed solution on a magnetic stirrer to obtain a precursor solution, pouring a proper amount of the precursor solution into a polytetrafluoroethylene mold, paving the mixture, and performing cross-linking polymerization in a blast oven to form a film. The three-dimensional thioether crosslinked network structure provided by the invention has a large number of weakly coordinated thioether groups, can promote the dissociation of lithium salt, generate a large number of free Li + , increase the number of Li + , and simultaneously obviously reduce the crystallinity of the polymer, so that the ionic conductivity is improved, the mechanical stability of the membrane is improved, and the service life of a battery is effectively prolonged.

Inventors

  • CHENG YU
  • ZHANG YI
  • YANG YINGKUI
  • BI SHUGUANG
  • RAN JIANHUA
  • Liang Caiqian

Assignees

  • 武汉纺织大学

Dates

Publication Date
20260505
Application Date
20260208

Claims (9)

  1. 1. A method for preparing a thioether crosslinked solid polymer electrolyte membrane, comprising the steps of: S1, taking N, N-dimethylformamide, respectively adding 3, 6-dioxa-1, 8-octane dithiol and isocyanuric acid triglycidyl ester, and uniformly mixing to obtain a mixed solution; S2, adding lithium bis (trifluoromethylsulfonyl) imide into the mixed solution, and stirring to completely dissolve the lithium bis (trifluoromethylsulfonyl) imide to obtain a precursor solution; s3, pouring a proper amount of precursor solution into a polytetrafluoroethylene mould, paving, and polymerizing and crosslinking in a blast oven to form a film, thus obtaining the solid polymer electrolyte membrane.
  2. 2. The process according to claim 1, wherein in step S1, the molar ratio of 3, 6-dioxa-1, 8-octanedithiol to triglycidyl isophthalonitrile to triglycidyl isocyanurate is 1-3:1.
  3. 3. The preparation method according to claim 1, wherein the mass ratio of N, N-dimethylformamide to 3, 6-dioxa-1, 8-octanedithiol is 25:3-1.
  4. 4. The method according to claim 1, wherein in step S2, the molar ratio of 3, 6-dioxa-1, 8-octanedithiol to lithium bis (trifluoromethylsulfonyl) imide is 3:2-1.
  5. 5. The method according to claim 3, wherein in step S2, magnetic stirring is used, the rotation speed of the magnetic stirring is 1000-1500 rpm, the temperature is 50-100 ℃ and the time is 5-7 h.
  6. 6. The method according to claim 1, wherein in step S3, the polymerization temperature is 60 to 80 ℃ and the polymerization time is 4 to 5 h.
  7. 7. A thioether crosslinked solid polymer electrolyte membrane, characterized by being produced by the production method according to any one of claims 1 to 6.
  8. 8. The thioether-crosslinked solid polymer electrolyte membrane according to claim 7, wherein the thioether-crosslinked solid polymer electrolyte membrane has a thickness of from 30 to 100 μm.
  9. 9. Use of the thioether crosslinked solid polymer electrolyte membrane according to claim 7 or 8 in a solid state lithium ion battery.

Description

Thioether crosslinked solid polymer electrolyte membrane and preparation method and application thereof Technical Field The invention relates to the technical field of electrolytes, in particular to a thioether crosslinked solid polymer electrolyte membrane, a preparation method and application thereof. Technical Field Solid state lithium metal batteries have higher energy density and superior safety compared to conventional liquid electrolyte lithium ion batteries, making them a potential candidate for future development of electric vehicles. The solid electrolyte is used as an important component of the solid lithium metal battery, and has great influence on the cycle stability and the service life of the solid lithium metal battery. Among the solid electrolytes, although the inorganic solid electrolyte has high ion conductivity and exhibits excellent thermal/chemical stability, poor interface contact may cause problems such as high interface resistance and non-uniform lithium ion transport, and the preparation cost of the inorganic solid electrolyte is high, which is difficult to be industrially applied. In contrast, solid polymer electrolytes exhibit good interfacial contact due to their high flexibility and processability. Solid polymer electrolytes, particularly polyether electrolytes, have been widely studied for their high ether group solvating ability and optimal chain spacing. However, the most commonly used polyethylene oxide has a high crystallinity and a high melting point, resulting in poor ionic conductivity and a low cation transfer number, which hinders its practical application in solid molecular films. Disclosure of Invention In view of this, it is possible, In order to achieve the above purpose, the technical scheme of the invention is realized as follows: A method for preparing a thioether crosslinked solid polymer electrolyte membrane, comprising the steps of: s1, taking a proper amount of N, N-dimethylformamide, respectively adding 3, 6-dioxa-1, 8-octane dithiol and isocyanuric acid triglycidyl ester, and uniformly mixing to obtain a mixed solution; S2, adding lithium bis (trifluoromethyl sulfonyl) imide into the mixed solution, and adding a magneton on a magnetic stirrer to completely dissolve the lithium bis (trifluoromethyl sulfonyl) imide to obtain a precursor solution; s3, pouring a proper amount of precursor solution into a polytetrafluoroethylene die, paving, and polymerizing and crosslinking in a blast oven to form a film, thus obtaining the thioether crosslinked network type polymer electrolyte. Further, in the step S1, the molar ratio of the 3, 6-dioxa-1, 8-octanedithiol to the triglycidyl isophthalonitrile urate is 1-3:1. Further, the mass ratio of the N, N-dimethylformamide to the 3, 6-dioxa-1, 8-octanedithiol is 25:3-1. Further, in the step S2, the molar ratio of the 3, 6-dioxa-1, 8-octanedithiol to the lithium bis (trifluoromethylsulfonyl) imide is 3:2-1. Further, in step S2, the rotation speed of the magnetic stirring is 1000-1500 rpm, the temperature is 50-100 ℃ and the time is 5-7 h. Further, in step S3, the polymerization temperature is 60-80 ℃ and the polymerization time is 4-5 h. On the basis of the scheme, the second object of the invention is to provide a thioether crosslinked solid polymer electrolyte membrane, which is prepared by adopting the preparation method, and comprises thioether crosslinked network polymer and bis (trifluoromethyl sulfonyl) imide lithium. Further, the thickness of the thioether-crosslinked solid polymer electrolyte membrane is from 30 to 100. Mu.m. Based on the scheme, a third object of the invention is to provide application of thioether crosslinked solid polymer electrolyte membrane in solid lithium ion batteries. Compared with the prior art, the invention has the following advantages: (1) Firstly, the invention is based on thiol-epoxy click chemistry, and S atoms in mercapto groups of 3, 6-dioxa-1, 8-octanedithiol have lone pair electrons which are used as nucleophiles to attack ternary rings of isocyanuric acid triglycidyl epoxy groups. The epoxy three-membered ring is opened by a nucleophile to generate a three-dimensional thioether crosslinked network structure. A large amount of weakly coordinated thioether groups can promote dissociation of lithium salts, producing a large amount of free Li +, increasing the amount of Li +. And secondly, the steric hindrance of the three-dimensional thioether crosslinked network crosslinked points can prevent ordered stacking of molecular chains, so that the crystallinity of the polymer is obviously reduced, the proportion of an amorphous region is enlarged, the segment movement capacity is improved, the activation energy of segment movement of an amorphous region is reduced, and the ionic conductivity is improved. Meanwhile, the weak polarity of the thioether group enables interaction force among molecular chains to be weak, friction resistance among molecular chain segments is small, and chain