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CN-121983745-A - Triazine structure flexible polyimide COF composite diaphragm, preparation method and application thereof in water-based zinc-iodine battery

CN121983745ACN 121983745 ACN121983745 ACN 121983745ACN-121983745-A

Abstract

The invention provides a triazine structure flexible polyimide COF composite diaphragm, a preparation method and application thereof in a water system zinc-iodine battery, and relates to the technical field of water system zinc-iodine batteries. The composite diaphragm is prepared by uniformly coating pyromellitic dianhydride (PMDA) and 2,4, 6-tris (4-aminophenyl) -1,3, 5-triazine (TPT) on the surface of a glass fiber diaphragm after preparing an organic framework material in an o-dichlorobenzene/N-methylpyrrolidone mixed solvent by a solvothermal method. The area capacity of the water-based zinc-iodine battery of the composite diaphragm prepared by adopting the triazine structure and the flexible annular design reaches 7.8 to mAh cm ‑2 under the ultra-high area current density of 20 mA cm ‑2 , the high capacity and the high coulomb efficiency are still maintained after 800 cycles, the zinc ion diffusion coefficient is as high as 4.07 multiplied by 10 ‑8 cm²s ‑ 1, and the performance is obviously superior to that of the conventional diaphragm modification technology.

Inventors

  • YANG WEITING
  • LIANG YUBO
  • WANG JIANYI
  • GAO YANAN
  • SU XIAOFANG
  • CHEN MENGHUI
  • HU HUI

Assignees

  • 海南大学

Dates

Publication Date
20260505
Application Date
20260226

Claims (10)

  1. 1. The preparation method of the triazine structure flexible polyimide COF composite membrane is characterized by comprising the following steps of: step 1, performing ultrasonic treatment on pyromellitic dianhydride and 2,4, 6-tris (4-aminophenyl) -1,3, 5-triazine ligand in a mixed solvent to form a mixed solution; Step 2, heating, washing, purifying and drying the mixed solution to obtain a two-dimensional covalent organic framework; And step 3, assembling the obtained two-dimensional covalent organic framework and the conductive material on the membrane to obtain the flexible polyimide (COF) composite membrane with the triazine structure.
  2. 2. The preparation method of the triazine structure flexible polyimide COF composite membrane according to claim 1 is characterized in that the molar ratio of pyromellitic dianhydride to 2,4, 6-tris (4-aminophenyl) -1,3, 5-triazine is 3-5:2, and the dosage ratio of 2,4, 6-tris (4-aminophenyl) -1,3, 5-triazine to mixed solvent is 1-2mmol:20-40mL.
  3. 3. The method for preparing the triazine structure flexible polyimide COF composite membrane according to claim 1, wherein the mixed solvent comprises o-dichlorobenzene and N-methylpyrrolidone in a volume ratio of 1-3:1-7.
  4. 4. The preparation method of the triazine structure flexible polyimide COF composite membrane according to claim 1, wherein the ultrasonic time is 10-12min, and the heating temperature is 160-180 ℃ and the time is 100-120h.
  5. 5. The preparation method of the triazine structure flexible polyimide COF composite membrane according to claim 1 is characterized in that the conductive material is one or more selected from graphene, ketjen black, carbon black and acetylene black, and the membrane is one selected from filter paper and glass fiber membrane.
  6. 6. A triazine-structured flexible polyimide COF composite membrane produced by the production method of any one of claims 1 to 5.
  7. 7. The triazine structure flexible polyimide COF composite membrane of claim 6, wherein the triazine structure flexible polyimide COF composite membrane has a diameter of 18-20 mm and a thickness of 800-900 μm before assembly.
  8. 8. Use of the triazine structure flexible polyimide COF composite membrane prepared by the preparation method of any one of claims 1 to 5 or the triazine structure flexible polyimide COF composite membrane of any one of claims 6 to 7 in the preparation of an aqueous zinc-iodine battery.
  9. 9. The use according to claim 8, wherein the aqueous zinc-iodine battery comprises a positive electrode, a negative electrode, an electrolyte and a triazine structured flexible polyimide COF composite separator.
  10. 10. The use according to any one of claims 8-9, wherein the aqueous zinc-iodine battery is used in energy storage devices, power grid peak shaving energy storage, low speed electric vehicles, road lighting, harbor machinery, emergency power supplies.

Description

Triazine structure flexible polyimide COF composite diaphragm, preparation method and application thereof in water-based zinc-iodine battery Technical Field The invention relates to the technical field of water-based zinc-iodine batteries, in particular to a triazine structure flexible polyimide (COF) composite diaphragm, a preparation method and application thereof in a water-based zinc-iodine battery. Background As an emerging water-based secondary battery, a water-based zinc-iodine battery (aqueous zinc-iodine batteries, abbreviated as Zn-I 2 battery) has the outstanding advantages of high safety, low cost, high theoretical energy density (the double electron transfer theoretical specific capacity of iodine reaches 422 mAh/g, the zinc cathode theoretical specific capacity of 820 mAh/g), abundant resources, environmental friendliness and the like, and is regarded as ideal choice for large-scale energy storage, renewable energy integration and flexible/wearable equipment. Compared with other water-based zinc batteries (such as zinc-manganese and zinc-vanadium systems), the zinc-iodine battery has moderate oxidation-reduction potential and strong reaction reversibility, and has higher power density and energy density potential. However, the commercialization process of aqueous zinc-iodine batteries is still subject to a number of core technical bottlenecks, mainly arising from the conversion reaction mechanism of the iodine positive electrode (I -I0I +, related to the formation and dissolution of polyiodides such as I 3-、I5-) and instability of zinc anodes. On the positive electrode side, even if a high specific surface area carbon material such as commercial coconut shell activated carbon is used as an iodine carrier, a certain physical limit and adsorption sites can be provided, but the conductivity of iodine species is poor, the reaction kinetics is slow, the polarization under high load is serious, and the generated polyiodide is easy to dissolve in a water-based electrolyte and diffuse to a zinc negative electrode, so that a serious polyiodide shuttle effect (polyiodide shuttle effect) is caused, and the loss of active substances, the self-discharge, the low coulomb efficiency and the rapid capacity decay are caused. On the negative side, zinc metal is prone to dendrite growth (HER), hydrogen evolution side reaction (HER), surface corrosion and passivation during cycling, forming dead zinc and uneven deposition, further exacerbating the shuttle effect, reducing zinc utilization and shortening battery life. These problems together limit the high area capacity (typically <5 mAh/cm 2), high rate performance and long stability of the battery. In the prior art, in order to alleviate the problems, research is mainly conducted from the aspects of anode host optimization, electrolyte regulation, diaphragm modification, anode protection and the like: (1) In the aspect of the anode, commercial coconut shell activated carbon is widely used as an iodine carrier due to low cost and high specific surface area (generally more than 1500 m < 2 >/g), a certain degree of iodine limiting domain is realized through physical adsorption, but the specific chemical adsorption sites and catalytic activity are lacked, the polyiodide dissolution and shuttling cannot be effectively inhibited, and the dynamics under high load are still limited. (2) In the aspect of the diaphragm, the traditional glass fiber diaphragm has insufficient shielding capability on polyiodide. In recent years, triazinyl Covalent Organic Framework (COF) modified membranes have become a research hotspot, and utilize nitrogen-rich sites of triazine rings to electrostatically repel polyiodide anions, promote uniform transmission of Zn 2+, and realize certain dendrite inhibition and cycle improvement. (3) In the aspect of the cathode, an artificial interface layer (such as a polymer, MOF and a carbon coating) is used for inhibiting dendrite and corrosion, but the existing protective layer is mostly made of rigid materials, and the coating has poor uniformity, insufficient mechanical flexibility and easy cracking or stripping in circulation and cannot meet the requirements of high current density and flexible devices. (4) In the aspect of electrolyte, an additive or high-concentration salt is introduced to regulate and control a solvation structure, so that shuttle and HER are partially relieved, but the problem of an interface cannot be fundamentally solved. Although triazinyl COFs exhibit zinc affinity polyiodine rejection advantages in zinc-iodine battery separator modification, polyimide-based COFs exhibit excellent chemical stability and carbonyl activity in other systems, most of the existing COF materials are rigid layered structures, have poor flexibility and limited mechanical strength, and are difficult to realize uniform and compact interface coatings or flexible battery applications. Meanwhile, no flexible annular COF material combining a triazine st