Search

CN-122025788-A - Preparation method and application of lithium ion gel electrolyte containing functional coupling 3D COFs material

CN122025788ACN 122025788 ACN122025788 ACN 122025788ACN-122025788-A

Abstract

The invention discloses a preparation method and application of a lithium ion gel electrolyte containing a functional coupling 3D COFs, and belongs to the technical field of lithium ion battery electrolytes. The invention adopts porphyrin/phthalocyanine-hydrazide functional coupling 3D COFs material as a modified component, and the material is prepared by connecting porphyrin/phthalocyanine aldehydes with a hydrazide building block through an acylhydrazone bond, and has the synergistic function of a three-dimensional intercommunication pore canal and a catalytic site-adsorption site. The prepared gel electrolyte consists of a polymer matrix, the 3D COFs material, lithium salt and an organic solvent according to a specific proportion, and the preparation process adopts a solution blending process, does not need an additional initiator, and is simple and controllable. The invention breaks through the bottleneck of unbalanced performance and complex process of the traditional 2D COFs gel electrolyte, obviously improves the ion conductivity, the lithium ion migration number and the cycling stability of the lithium ion battery, and is suitable for semi-solid/solid lithium ion batteries and various electrode systems.

Inventors

  • JIANG RONG
  • WANG RUIRUI
  • LI CHUNLI
  • LIU ZHIXIN
  • ZHAN XIAONING

Assignees

  • 北京化工大学

Dates

Publication Date
20260512
Application Date
20260319

Claims (10)

  1. 1. A method for preparing a lithium ion gel electrolyte containing a functionally coupled 3D COFs, comprising the steps of: s1, preparing a functional coupling 3D COFs material, wherein the functional coupling 3D COFs material is prepared by performing acylhydrazone bond condensation reaction on porphyrin/phthalocyanine group building elements and hydrazide group building elements; S2, dispersing the polymer, the lithium salt and the plasticizer into a solvent according to a preset proportion, and uniformly stirring and mixing to obtain a polymer matrix solution; s3, adding the prepared functionally coupled 3D COFs material into a polymer matrix solution, and uniformly stirring to uniformly disperse the functionally coupled 3D COFs material in the system, so as to obtain a stable precursor solution; And S4, transferring the precursor solution into a custom mold for drying, and removing the solvent to form the uniform 3D COFs composite lithium ion gel electrolyte membrane.
  2. 2. The method for preparing the lithium ion gel electrolyte containing the functionally coupled 3D COFs according to claim 1, wherein in the step S2, the polymer is selected from one or more of polyethylene oxide, polypropylene carbonate, polyvinylidene fluoride-hexafluoropropylene copolymer and polymethyl methacrylate, the lithium salt is selected from one or more of lithium bis (trifluoromethanesulfonyl) imide, lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide and lithium trifluoromethanesulfonate, the plasticizer is selected from one or more of propylene carbonate, ethylene carbonate, tetraglyme and polyethylene glycol dimethyl ether, and the solvent is one or two of acetonitrile and N, N-dimethylformamide.
  3. 3. The preparation method of the lithium ion gel electrolyte containing the functionally coupled 3D COFs, which is characterized in that in the step S2, the preset proportion of the polymer, the lithium salt and the plasticizer is (6-8): 1-2): 3-5: (mol ratio), the stirring temperature is 30-50 ℃ and the stirring time is 2-4 h.
  4. 4. The preparation method of the lithium ion gel electrolyte containing the functional coupling 3D COFs, which is disclosed in claim 1, is characterized in that in the step S3, the mass ratio of the functional coupling 3D COFs material to the polymer matrix is (1-3): 7-9, and the precursor solution is obtained by adding the functional coupling 3D COFs material and stirring for 6-10 h at the temperature of 50-70 ℃.
  5. 5. The method for preparing the lithium ion gel electrolyte containing the functionally coupled 3D COFs according to claim 1, wherein the functionally coupled 3D COFs material in step S1 is formed into a three-dimensional interworking crystalline framework by a condensation reaction of porphyrin/phthalocyanine group building elements and hydrazide group building elements through acylhydrazone bonds.
  6. 6. The method for preparing a lithium ion gel electrolyte containing a functionally coupled 3D COFs according to claim 5, wherein after porphyrin/phthalocyanine group building elements and hydrazide group building elements are mixed to form a mixed solution, a catalyst is added into the mixed solution, the mixed solution is placed in a liquid nitrogen bath to perform a freezing-pumping-thawing cycle, then a 3D COFs framework is formed through an acylhydrazone bond condensation reaction under a heating condition, and finally the generated 3D COFs framework is washed and dried to obtain the functionally coupled 3D COFs material.
  7. 7. The method for preparing a lithium ion gel electrolyte comprising functionally coupled 3D COFs according to claim 5, wherein the porphyrin/phthalocyanine group building element is selected from one or more of 5,10,15, 20-tetra (4-aldehyde phenyl) porphyrin (p-Por-CHO), 5,10,15, 20-tetra ([ 1,1':3',1 "-terphenyl ] -4, 4" -dicarboxaldehyde group)) -porphyrin (TTEP), tetra-aldehyde group phthalocyanine and 2,3,9,10,16,17,23,24-eight (4-aldehyde phenyl) phthalocyanine, wherein the central metal M of the phthalocyanine group building element is selected from one or more of V, cr, mn, zn, co, ni, cu, fe; the hydrazide group building element is a hydrazide derivative taking tricarbazolyl benzene as a center or a hydrazide derivative taking triazene as a center; preferably, the hydrazino building block is a 12-linked 5,5',5 ", 5 '" ' - (9, 10-dihydro-9, 10- [1,2] benzanthracene-2,3,6,7,14,15-hexa-yl) hexa (isophthalhydrazide).
  8. 8. The method for preparing a lithium ion gel electrolyte containing a functionally coupled 3D COFs according to claim 5, wherein the molar ratio of porphyrin/phthalocyanine group building elements to hydrazide group building elements is (1-2): 1-1.5.
  9. 9. The preparation method of the lithium ion gel electrolyte containing the functionally coupled 3D COFs, which is disclosed in claim 6, is characterized in that the catalyst is one or more selected from quinoline, isoquinoline, triethylamine and 4-dimethylaminopyridine, the mixed solution further comprises an organic solvent, the volume ratio of the organic solvent to the catalyst is 10 (1-1.5), the times of freezing-pumping-thawing cycles are 3-5, the target temperature of the freezing stage is-196 ℃ to-80 ℃, the target temperature of the thawing stage is room temperature, and the vacuum degree of the pumping stage is less than or equal to 10Pa.
  10. 10. The method for preparing the lithium ion gel electrolyte containing the functionally coupled 3D COFs, which is disclosed in claim 6, is characterized in that after the freeze-air suction-thawing cycle is completed, acylhydrazone bond condensation reaction is carried out at 160-180 ℃ for 96-120 hours to form a 3D COFs framework, and the generated 3D COFs framework is washed for three times, wherein cleaning agents used for the three times are tetrahydrofuran, water and acetone respectively.

Description

Preparation method and application of lithium ion gel electrolyte containing functional coupling 3D COFs material Technical Field The invention belongs to the technical field of lithium ion battery electrolyte materials, in particular relates to a lithium ion battery electrolyte material modification technology, and particularly relates to a functional coupling 3D COFs material for lithium ion gel electrolyte modification, and preparation and application of a gel electrolyte containing the material. Background At present, a commercial lithium ion battery mainly adopts a liquid electrolyte, but has potential safety hazards of liquid leakage, inflammability, easy initiation of lithium dendrite growth and the like, and the application of the battery in a high-energy density scene is limited. The gel electrolyte is used as an intermediate material between the liquid electrolyte and the solid electrolyte, so that the gel electrolyte not only maintains good interface compatibility and higher ionic conductivity of the liquid electrolyte, but also has excellent mechanical strength and flame retardant property of the solid electrolyte, and becomes an important direction for solving the safety problem of the liquid electrolyte. However, the conventional gel electrolyte has the defects that the ionic conductivity is difficult to achieve both normal temperature and low temperature performances, the ionic migration rate is obviously reduced at low temperature, the mechanical stability is insufficient, deformation and cracking are easy to occur in the battery charge-discharge cycle process, interface contact failure is caused, the compatibility with an electrode interface is poor, side reactions are easy to occur to generate an unstable solid electrolyte interface film, and the battery cycle life is influenced. In order to solve the problems, researchers often modify gel electrolyte by adding nano-fillers, while the traditional inorganic fillers can improve mechanical properties, the traditional inorganic fillers have poor compatibility with an organic gel matrix, are easy to generate agglomeration phenomenon, and reduce the comprehensive properties of the electrolyte. Covalent Organic Frameworks (COFs) are crystalline porous materials formed by covalent bonding of organic monomers, wherein 3D COFs have more complex ordered pore structures than 2D COFs with one-dimensional channels, which are more conducive to the transport of molecules and ions, and if specific functional sites are introduced into 3D COFs, the synergistic effect with gel electrolytes can be further enhanced. However, in the existing composite system of COF and gel electrolyte, COF materials are mostly in a single functional 2D structure, a dual-functional 3D structure design with ion transmission promotion and interface reaction regulation is lacking, the composite method has the problems of complex process, uneven COF dispersion, low functional site utilization rate and the like, the development of the 3D COFs composite gel electrolyte with high conductivity, strong mechanical property and excellent interface stability is still in an exploration stage, and in the prior art, the report of applying the 3D COFs with 'catalysis-adsorption-transmission' function coupling to the lithium ion gel electrolyte is not yet available, so that the development of the composite material and the preparation method thereof is of great significance in promoting the industrialization of high-safety and high-performance lithium ion batteries. In view of this, the present invention has been made. Disclosure of Invention The invention aims to overcome the defects of potential safety hazard, low ionic conductivity, insufficient mechanical strength, poor interface compatibility and the like of the traditional lithium ion electrolyte, and simultaneously solve the problems of limited pore channel transmission efficiency, single function and insufficient compatibility in a 2D COFs composite system, and provides a preparation method of the lithium ion gel electrolyte containing a functional coupling 3D COFs material, a preparation method of the 3D COFs material and a battery application scheme. In order to achieve the above object, the present invention provides a method for preparing a lithium ion gel electrolyte comprising a functionally coupled 3D COFs material, comprising the steps of: (1) Preparing a functional coupling 3D COFs material, wherein the functional coupling 3D COFs material is prepared by performing acylhydrazone bond condensation reaction on porphyrin/phthalocyanine group building elements and hydrazide group building elements; (2) Dispersing a polymer, lithium salt and a plasticizer into a solvent according to a preset proportion, and uniformly stirring and mixing to obtain a polymer matrix solution; (3) Adding the prepared functional coupling 3D COFs material into a polymer matrix solution, and uniformly stirring to uniformly disperse the functional coupling 3D