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CN-122025444-A - Method for preparing flame-retardant gel polymer electrolyte by in-situ polymerization and application of flame-retardant gel polymer electrolyte in super capacitor

CN122025444ACN 122025444 ACN122025444 ACN 122025444ACN-122025444-A

Abstract

The invention discloses a method for preparing a flame-retardant gel polymer electrolyte by in-situ polymerization and application of the flame-retardant gel polymer electrolyte in a super capacitor, and belongs to the technical field of super capacitors. The method solves the problems of poor contact and unbalanced performance of the flame-retardant electrolyte and the electrode interface by constructing a precursor solution containing a bromine-phosphorus synergistic flame-retardant unit step by step and polymerizing in situ. The phosphorus-nitrogen synergistic mechanism forms a gas phase and solid phase dual flame-retardant protective layer, the auxiliary additive adjusts rheological property to ensure that flame-retardant components are uniformly dispersed, and the lithium salt coordinates with polar groups to inhibit migration of the flame retardant and enhance mechanical strength. In-situ polymerization enables the cross-linked polymer network to be combined with the electrode molecular level, so that a three-dimensional ion transmission channel is constructed, interface impedance is reduced, and the contact defect of the traditional solid electrolyte is avoided. By defining the mass ratio of flame retardant to auxiliary additive, flame retardant-electrochemical performance balance is achieved. Compared with the prior art, the liquid precursor completely infiltrates the electrode pores, is polymerized into gel and then is in seamless connection with the electrode, the bromine-phosphorus synergic flame retardant interrupts the combustion chain reaction and generates the heat insulation carbon layer, the safety of the supercapacitor is improved, and the energy density is kept stable.

Inventors

  • ZHANG LISONG
  • LIU GUANGCHEN
  • LI JINGYU
  • SUN WEI
  • TIAN GUIZHEN
  • XIN FUQIANG
  • DONG SHUXIN
  • ZHAO JUNRUI
  • CUI WENXI
  • WANG ZHIPENG
  • LIU XIANGLIANG
  • Dai Benqian
  • BAI JINQUAN
  • CHEN HAO
  • ZHAO KUN
  • WU PENGYUE
  • WANG XIAOHUI
  • CHEN SI
  • Lou Fangxi
  • XUE LEI
  • Gao Yushuan
  • Bian Shengjun

Assignees

  • 西安热工研究院有限公司
  • 华能伊敏煤电有限责任公司

Dates

Publication Date
20260512
Application Date
20260204

Claims (10)

  1. 1.A method for preparing a flame retardant gel polymer electrolyte by in situ polymerization, comprising: S1, adding a super flame retardant additive and an auxiliary additive into a mixed solvent, and stirring and dissolving to obtain a mixed solution; s2, adding lithium salt into the mixed solution for dissolution, and stirring to obtain a precursor solution; s3, dropwise adding the precursor solution to the surface of the electrode of the supercapacitor, and heating to initiate ring-opening polymerization of the 1, 3-dioxolane to form a flame-retardant gel polymer electrolyte with a crosslinked structure on the surface of the electrode in situ; The structural formula of the super flame retardant additive is 。
  2. 2. The method for preparing a flame retardant gel polymer electrolyte by in situ polymerization according to claim 1, wherein in S1, the auxiliary additive is any one of vinylene carbonate, tripropylene borate and vinyl sulfate.
  3. 3. The method for preparing the flame-retardant gel polymer electrolyte by in-situ polymerization according to claim 1, wherein in S1, the mixed solvent is prepared from 1, 3-dioxolane, fluoroethylene carbonate, ethylene carbonate, diethyl carbonate and methyl ethyl carbonate in a volume ratio of 15-18:1:4-6:4-6:5-6.
  4. 4. The method for preparing the flame-retardant gel polymer electrolyte by in-situ polymerization, according to claim 1, wherein in S1, the mass volume ratio of the total addition amount of the super flame-retardant additive and the auxiliary additive to the mixed solvent is 3-4 mg/100 mL.
  5. 5. The method for preparing the flame-retardant gel polymer electrolyte by in-situ polymerization, according to claim 4, wherein the mass ratio of the super flame-retardant additive to the auxiliary additive is 10-12:1.
  6. 6. The method for preparing the flame-retardant gel polymer electrolyte by in-situ polymerization according to claim 1, wherein in S2, the lithium salt is lithium hexafluorophosphate, the mass volume ratio of the lithium salt to the mixed solution is 12-14 mg/100 mL, the stirring temperature is 23-27 ℃, and the stirring time is 30-60 min.
  7. 7. The method for preparing the flame-retardant gel polymer electrolyte by in-situ polymerization according to claim 1, wherein in S3, the heating initiation temperature is 60-90 ℃ and the heating initiation time is 2-4 h.
  8. 8. The method for preparing the flame-retardant gel polymer electrolyte by in-situ polymerization according to claim 1, wherein in S3, the super capacitor is prepared by the steps of preparing a positive electrode shell, a positive electrode plate, a diaphragm, a precursor solution, a graphite plate, a stainless steel plate, an elastic sheet and a negative electrode shell in sequence, wherein NCM811 is selected as the positive electrode, and natural graphite is selected as the negative electrode.
  9. 9. A flame retardant gel polymer electrolyte prepared by the method of any one of claims 1 to 8.
  10. 10. Use of the flame retardant gel polymer electrolyte of claim 9 in a supercapacitor.

Description

Method for preparing flame-retardant gel polymer electrolyte by in-situ polymerization and application of flame-retardant gel polymer electrolyte in super capacitor Technical Field The invention belongs to the technical field of supercapacitors, and particularly relates to a method for preparing a flame-retardant gel polymer electrolyte by in-situ polymerization and application of the flame-retardant gel polymer electrolyte in a supercapacitor. Background Super capacitor is used as an important electrochemical energy storage device, and has been widely applied in the fields of new energy automobiles, portable electronic equipment, smart grids and the like by virtue of the advantages of high power density, high charge and discharge speed, long cycle life and the like. However, commercial supercapacitors commonly employ liquid electrolytes based on carbonate-based organic solvents, which, while having relatively high ionic conductivity, have inherent disadvantages of high volatility, low flash point, and flammability and explosiveness. Under extreme conditions of high temperature (> 60 ℃), overvoltage, internal short circuit, mechanical abuse and the like, electrolyte leakage, severe gas generation and thermal runaway are extremely easy to occur, and finally combustion and even explosion accidents are caused. This fundamental potential safety hazard becomes a core obstacle limiting the expansion of supercapacitors to higher energy densities and wider application areas. Therefore, the development of high-safety and high-performance electrolyte materials has become a core development direction in the field of supercapacitors. To break through the safety bottleneck, the use of solid or quasi-solid electrolytes instead of liquid electrolytes has become a necessary trend. The prior art mainly develops and optimizes about three paths, namely, developing an intrinsic flame-retardant polymer matrix, and constructing a polymer with intrinsic flame-retardant property by chemically introducing flame-retardant functional units such as phosphorus (P), nitrogen (N), silicon (Si) and the like on a polymer main chain or a side chain such as polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polymethyl methacrylate (PMMA) and the like, wherein the synthesis process of the polymer is complex and high in cost, and the introduction of a rigid flame-retardant group often damages the chain segment movement capability of the polymer and the wettability of the polymer to an electrode, so that the ionic conductivity is reduced, the interface compatibility with the electrode is poor, and the interface impedance is increased; secondly, constructing a composite flame-retardant system, introducing a phosphorus-based, nitrogen-based, halogen-based or inorganic nano flame retardant into a polymer network through a physical blending or covalent bond anchoring mode, wherein although the flame-retardant effect can be improved, the physical blending is easy to cause agglomeration of the flame retardant, the ion transmission efficiency is reduced, the covalent bond anchoring can sacrifice the flexibility and interface contact performance of the polymer, thirdly, designing an intelligent thermally-responsive electrolyte, introducing a thermally-induced phase-change material, a dynamic covalent bond and the like to prepare an electrolyte with a temperature-sensitive protection or self-healing function, and the material can trigger physical/chemical state transition to block current when in thermal abuse or realize partial functional recovery after damage, however, the problems of high response threshold, low speed, harsh repair conditions, insufficient long-term electrochemical cycling stability and the like generally exist, and the material has a distance from practical application. Besides the materials, the existing gel polymer electrolyte preparation process also severely restricts the device performance, and currently, a mode of prefabricating a film-assembling device is mainly adopted, namely, a solid polymer electrolyte film is firstly prepared by solution casting, electrostatic spinning and other methods, and then the solid polymer electrolyte film, an electrode and a diaphragm are assembled into a device. Because of complex micro/nano-scale pores and a coarse structure on the surface of the electrode, rigid contact is formed between the prepared solid film and the electrode, a large number of gaps and interface defects are inevitably generated, so that the interface impedance is obviously increased, the transmission efficiency of lithium ions is seriously restricted, meanwhile, the wettability of the film is insufficient, the electrode pores cannot be completely covered, and the problems of capacity attenuation and poor cycling stability are further aggravated. In summary, although the prior art has been explored from the viewpoint of improving flame retardance or optimizing single performance, the following common problems are face