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CN-122000451-A - Preparation method and application of flame-retardant N, S-containing in-situ polymerization gel electrolyte

CN122000451ACN 122000451 ACN122000451 ACN 122000451ACN-122000451-A

Abstract

The invention belongs to the technical field of polymer solid-state batteries, and particularly relates to a preparation method and application of a flame-retardant N, S-containing in-situ polymerized gel electrolyte. The gel electrolyte consists of a diolefin chain extender, a dimercapto chain extender, a trifunctional isocyanurate-containing cross-linking agent, a catalyst, an organic electrolyte and lithium salt, and is polymerized in situ in the battery through mercapto-alkene click chemical reaction to form a three-dimensional network structure. The isocyanurate unit can improve the interface compatibility of the electrolyte and the electrode and the cycling stability of the battery. The electrolyte has the advantages of high ionic conductivity, low interface impedance, excellent thermal stability, incombustibility and the like, is suitable for lithium primary batteries and lithium secondary batteries, and is particularly suitable for in-situ polymerized lithium metal batteries with high requirements on safety. The method has the advantages of simple and convenient process and mild reaction conditions, is highly compatible with the existing liquid battery manufacturing process, and is favorable for realizing large-scale industrialized application.

Inventors

  • RUAN WENHONG
  • Akomat Qasim
  • MA MENGQI

Assignees

  • 中山大学

Dates

Publication Date
20260508
Application Date
20260204

Claims (10)

  1. 1. The flame-retardant N, S-containing in-situ polymerization gel electrolyte is characterized by comprising a diolefin chain extender, a dimercapto chain extender, a trifunctional isocyanurate-containing cross-linking agent, a catalyst, an organic electrolyte and lithium salt; The diene chain extender is selected from one or more of diallyl ether, divinyl sulfone, 1, 3-diallyl-2, 2-dimethyl malonate, N-diallyl acrylamide, dipropyleneamine, divinylbenzene, ethylene glycol dimethacrylate and polyethylene glycol diacrylate, the dimercapto chain extender is selected from one or more of 1, 2-ethanedithiol, 1, 5-pentanedithiol, 1, 6-hexandithiol, 1, 8-octadithiol, 1, 9-nonandithiol, 1, 10-decanedithiol, 1, 16-hexadecanedithiol, 1, 2-propanedithiol, 1, 2-benzene dithiol, 1, 2-octadithiol, butane-2, 2-dithiol, pyridine-2, 6-dithiol, p-terphenyl-4, 4' -dithiol, stilbene-2, 2' -dithiol, thiophene-3, 4-dithiol, durene-alpha 1, a 2-dithiol, 2, 3-piperazine dithiol, naphthalene-2, 3-dithiol, 1, 3-dione, 7-bis (2, 7-octadithiol), triglycidyl, 3-bis (2, 6-ethanedithiol), triglycidyl, 4' -dithiol, 3-bis (2, 6-ethanedithiol), triglycidyl, 3-bis (2, 6-isocyanurate) and triglycidyl isocyanurate, the triglycidyl amide is selected from one or more of these two or more of the following, one or more of tri [2- (3-mercaptopropionic acid) ethyl ] isocyanurate, and one or more of triethylamine, n-hexylamine, 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU) and dimethylphenylphosphine.
  2. 2. The flame retardant N, S-containing in situ polymerized gel electrolyte of claim 1, wherein the bis-olefin chain extender is selected from ethylene glycol dimethacrylate, the bis-mercapto chain extender is selected from 3, 6-dioxo-1, 8-octanedithiol, the trifunctional isocyanurate-containing cross-linker is selected from tris [2- (3-mercaptopropionyl) ethyl ] isocyanurate, and the catalyst is selected from triethylamine.
  3. 3. The flame retardant N, S-containing in situ polymerized gel electrolyte of claim 1, wherein the organic electrolyte comprises a mixed solvent of one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.
  4. 4. A flame retardant N, S-containing in situ polymeric gel electrolyte according to claim 1, wherein said lithium salt is selected from one or more of lithium LiClO 4 、LiPF 6 、LiCF 3 SO 3 、LiBF 4 、LiAsF 6 、LiSbF 6 、LiN(CF 3 SO 2 ) 2 、LiCF 3 CF 2 SO 3 、 difluoro (oxalato) borate, lithium (malonato oxalato) borate.
  5. 5. The method for preparing the flame-retardant N, S-containing in-situ polymerized gel electrolyte according to any one of claims 1 to 4, which comprises the following steps: S1, mixing a diolefin chain extender, a dimercapto chain extender and a trifunctional isocyanurate-containing cross-linking agent to prepare a polymer solution; S2, adding an organic electrolyte and lithium salt into the polymer solution of the S1, uniformly stirring, adding a catalyst, and stirring to obtain a precursor solution; And S3, standing and heating the precursor solution of the S2, and then performing in-situ crosslinking through a sulfhydryl-alkene clicking reaction to form a polymer network containing nitrogen and sulfur, and finally polymerizing to form the gel electrolyte.
  6. 6. The method for preparing a flame-retardant N, S-containing in-situ polymerized gel electrolyte according to claim 5, wherein the molar ratio of double bonds to mercapto groups in the diolefin chain extender, the dimercapto chain extender and the trifunctional isocyanurate-containing cross-linking agent is 1:1.
  7. 7. The method for preparing a flame retardant N, S-containing in situ polymerized gel electrolyte according to claim 5, wherein in S3, the standing is performed at room temperature for 10-15 h, and the heating is performed at 40-60 ℃ for 10-48 h.
  8. 8. Use of the flame retardant N, S-containing in situ polymerized gel electrolyte according to any of claims 1-4 in lithium metal batteries.
  9. 9. The use according to claim 8, wherein the lithium metal battery is a gel state polymer lithium battery or an all solid state polymer lithium battery, including lithium primary batteries and lithium secondary batteries.
  10. 10. The application of the lithium metal battery according to claim 8, wherein the specific application method is that after the diolefin chain extender, the dimercapto chain extender, the trifunctional isocyanurate-containing cross-linking agent, the catalyst, the organic electrolyte and the lithium salt are prepared into a precursor solution, the precursor solution is injected into a battery shell containing a positive plate, a porous diaphragm and a lithium metal negative electrode, and gel electrolyte is formed inside the battery after in-situ polymerization, so that the lithium metal battery is prepared.

Description

Preparation method and application of flame-retardant N, S-containing in-situ polymerization gel electrolyte Technical Field The invention belongs to the technical field of polymer solid-state batteries, and particularly relates to a preparation method and application of a flame-retardant N, S-containing in-situ polymerized gel electrolyte. Background Lithium metal batteries are recognized as one of the key core technologies for constructing next-generation high-energy-density energy storage systems by virtue of their high energy density and low reduction potential characteristics. However, the conventional liquid electrolyte (Liquid Electrolyte, LE) itself has flammability, and in addition, side reactions with the lithium metal negative electrode induce lithium dendrite growth, which severely restricts the large-scale commercial application of lithium metal batteries. Although researchers have developed polymer solid-state electrolytes in recent years to suppress the formation of lithium dendrites, such electrolytes have the common drawbacks of high interfacial resistance with lithium metal, low ionic conductivity, etc., so that all-solid-state lithium metal batteries have been difficult to industrialize until now. Gel polymer electrolytes (Gel Polymer Electrolyte, GPE) can significantly improve ionic conductivity while maintaining a certain mechanical strength by introducing a liquid electrolyte as a plasticizer into the polymer matrix. If the in-situ polymerization technology is further adopted, the monomer crosslinking reaction is directly initiated in the battery to construct GPE in situ, so that the interface impedance between the electrolyte and the electrode can be effectively reduced. In addition, the technology is highly compatible with the existing preparation technology of the liquid battery, and is beneficial to promoting large-scale mass production of the lithium metal battery. However, most current GPE systems still rely on flammable organic electrolytes as plasticizing components, resulting in their intrinsic safety being inadequate and presenting a combustion hazard. Therefore, developing a gel polymer electrolyte with flame retardant property is important to improving the safety performance of lithium metal batteries. At present, the GPE flame-retardant function is realized mainly by two technical paths, namely, the flame-retardant additive is added, the method is low in cost, but most commercial flame retardants are poor in electrochemical stability in a working potential window of a lithium metal battery, side reactions are easy to induce, and the cycle life of the battery is further damaged, and the flame-retardant function monomer unit is introduced into a polymer skeleton of the GPE in a chemical bonding mode, so that the intrinsic flame-retardant characteristic of the material can be endowed, and the safety and the cycle stability of the battery are expected to be cooperatively improved. Therefore, the development of the flame-retardant gel polymer electrolyte by using the flame-retardant monomer has important research value and application prospect. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a flame-retardant in-situ polymerization gel electrolyte containing nitrogen and sulfur elements, which consists of a diene chain extender, a dimercapto chain extender, a trifunctional isocyanurate-containing cross-linking agent, a catalyst, an organic electrolyte and lithium salt, and is polymerized in situ in a battery through a mercapto-alkene click chemical reaction to form a three-dimensional network structure. The invention successfully realizes the in-situ preparation of the polymer gel electrolyte by means of the mercapto-alkene click reaction and by utilizing the advantages of mild reaction conditions, simple and convenient operation, high reaction efficiency and no side reaction, and is expected to be widely applied to the field of intelligent lithium batteries. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the first aspect of the invention provides a flame-retardant N, S-containing in-situ polymerization gel electrolyte, which comprises a diolefin chain extender, a dimercapto chain extender, a trifunctional isocyanurate-containing cross-linking agent, a catalyst, an organic electrolyte and lithium salt; The diene chain extender is a double bond functional group polymer containing two vinyl groups and propenyl groups, and is selected from one or more of divinyl ketone, diallyl ether, divinyl sulfone, 1, 3-diallyl-2, 2-dimethyl malonate, N-diallyl acrylamide, dipropyleneamine, divinylbenzene, ethylene glycol dimethacrylate and polyethylene glycol diacrylate (molecular weight is within 200-10000); the dimercapto chain extender is selected from 1, 2-ethanedithiol, 1, 5-pentanedithiol, 1, 6-hexanedithiol, 1, 8-octadithiol, 1, 9-nonanedithiol, 1, 10-decanedithiol, 1, 16-hexadecanedit