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CN-122025793-A - Nitro-functionalized metal-organic framework-based composite solid electrolyte and preparation method and application thereof

CN122025793ACN 122025793 ACN122025793 ACN 122025793ACN-122025793-A

Abstract

The invention discloses a nitro functional metal organic framework-based composite solid electrolyte and a preparation method and application thereof, and belongs to the technical field of lithium batteries. The preparation method comprises the steps of carrying out hydrothermal reaction on zirconium salt and nitroterephthalic acid, carrying out centrifugal washing and drying to obtain nitrofunctionalized metal organic frame powder, carrying out ion stirring replacement on chitosan quaternary ammonium salt and lithium salt, carrying out centrifugal washing and drying to obtain polyion liquid powder, dissolving the nitrofunctionalized metal organic frame powder and the polyion liquid powder in an organic solvent to obtain a mixed solution, casting the mixed solution on a substrate, drying to obtain an electrolyte membrane, soaking the electrolyte membrane in an organic electrolyte, and fully absorbing to obtain the product. The composite solid electrolyte provided by the invention can obviously improve the ion conductivity and the migration number of lithium ions, inhibit the growth of lithium dendrites, improve the interfacial compatibility of electrodes and electrolytes, and further improve the cycling stability of a lithium metal battery.

Inventors

  • HUI XIAOBIN
  • Zhu Ruixiao
  • YIN LONGWEI
  • ZHAO YUTONG

Assignees

  • 山东大学
  • 山东大学苏州研究院

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. A preparation method of a nitro functional metal organic framework-based composite solid electrolyte comprises the following steps: (1) Carrying out hydrothermal reaction on zirconium salt and nitroterephthalic acid, and centrifugally washing and drying to obtain nitrofunctional metal-organic framework powder; (2) Ion stirring replacement is carried out on chitosan quaternary ammonium salt and lithium salt, and polyion liquid powder is obtained through centrifugal washing and drying; (3) Dissolving nitro functional metal organic frame powder and polyion liquid powder in an organic solvent to obtain a mixed solution, casting the mixed solution on a substrate, and drying to obtain an electrolyte membrane; (4) Soaking the electrolyte membrane in organic electrolyte, and fully absorbing to obtain the electrolyte membrane; In the step (2), the mass ratio of the chitosan quaternary ammonium salt to the lithium salt is 1:1.4-1.6; In step (2), the lithium salt is lithium bis (trifluoromethanesulfonyl) imide or lithium bis (fluorosulfonyl) imide; In the step (3), the mass fraction of the nitro-functional metal-organic framework powder is 1-9wt% based on the total mass of the nitro-functional metal-organic framework powder and the polyionic liquid powder.
  2. 2. The process according to claim 1, wherein in step (1), the molar ratio of zirconium salt to nitroterephthalic acid is 1:0.8-1.2; In the step (3), the mass of the organic solvent is 5-7 times of the total mass of the nitro functional metal organic frame powder and the polyion liquid powder.
  3. 3. The method of claim 1, wherein in step (1), the zirconium salt is zirconium tetrachloride or zirconium oxychloride; In the step (1), the solvent used in the hydrothermal reaction is N, N-dimethylformamide; in the step (2), the chitosan quaternary ammonium salt is hydroxypropyl trimethyl ammonium chloride chitosan; In step (3), the organic solvent is N-methylpyrrolidone; In the step (4), the organic electrolyte comprises lithium salt and a solvent, the lithium salt in the organic electrolyte comprises lithium bis (trifluoromethanesulfonyl) imide or lithium bis (fluorosulfonyl) imide, the solvent in the organic electrolyte comprises at least one of 1, 3-dioxolane, ethylene glycol dimethyl ether, ethylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate or fluoroethylene carbonate, and the concentration of the lithium salt in the organic electrolyte is 0.5-1.5 mol/L.
  4. 4. The method according to claim 1, wherein in the step (1), the temperature of the hydrothermal reaction is 115 to 125 ℃ and the time of the hydrothermal reaction is 22 to 26 hours; In the step (1), the rotational speed of centrifugal washing is 7800-8200rpm, the times of centrifugal washing is 2-4 times, the drying time is 22-26h, and the drying temperature is 50-70 ℃.
  5. 5. The method according to claim 1, wherein in the step (2), the ion stirring and displacement time is 5 to 7 hours, the centrifugal washing speed is 4800 to 5200rpm, the drying is freeze-drying, and the drying time is 22 to 26 hours.
  6. 6. The method of claim 1, wherein in the step (3), the mixed solution is cast on the substrate to a thickness of 90 to 110 μm; in the step (3), the drying temperature is 55-65 ℃ and the drying time is 10-14h.
  7. 7. The method of claim 1, wherein in step (4), the soaking time is 5 to 7 hours.
  8. 8. A nitro-functionalized metal-organic framework-based composite solid electrolyte, characterized in that it is obtained by the preparation method according to any one of claims 1 to 7.
  9. 9. Use of the nitro-functionalized metal-organic framework-based composite solid electrolyte of claim 8 in lithium metal batteries.
  10. 10. A lithium metal battery comprising a negative electrode, a positive electrode and a solid electrolyte, wherein the negative electrode is a lithium metal sheet, the positive electrode is a lithium iron phosphate positive electrode, and the solid electrolyte is the nitro-functional metal-organic framework-based composite solid electrolyte of claim 8.

Description

Nitro-functionalized metal-organic framework-based composite solid electrolyte and preparation method and application thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a nitro functional metal organic framework-based composite solid electrolyte, and a preparation method and application thereof. Background The information disclosed in the background of the invention is only for enhancement of understanding of the general background of the invention and is not necessarily to be taken as an admission or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art. The lithium metal battery becomes the core development direction of the next generation high energy density energy storage system because the lithium cathode has extremely high theoretical specific capacity and lowest oxidation-reduction potential. The electrolyte is used as a key medium for ion transmission in the battery, the performance of the electrolyte directly determines the cycle stability, the multiplying power performance and the safety performance of the battery, and the electrolyte is a core link for restricting the industrialization process of the lithium metal battery. In recent years, solid polymer electrolytes have become a research hotspot in the field of lithium metal battery electrolytes by virtue of advantages of good flexibility, capability of alleviating solid/solid interface point contact problems, excellent thermal stability, nonflammability and the like. However, the solid polymer electrolyte has short plates with slow ion transmission kinetics, and the room-temperature ion conductivity is usually lower than 10 -4S·cm-1, so that the practical application requirements are difficult to meet. Therefore, researchers construct gel polymer electrolyte by introducing electrolyte into solid polymer electrolyte, so that the flexibility and the thermal stability of the solid polymer electrolyte are reserved, the high ion conduction characteristic of the electrolyte is integrated, and the migration of ions in a polymer three-dimensional network can be accelerated. However, gel polymer electrolytes still have inherent defects that the migration number (t Li+) of lithium ions is generally less than 0.5, concentration polarization is easily caused by co-migration of anions and cations and lithium dendrite growth is aggravated, mechanical strength is insufficient, lithium dendrite puncture is difficult to resist, electrode and electrolyte interface compatibility is poor, irreversible side reaction is easily generated, and interface impedance is increased. To solve the above problems, the introduction of functional fillers to construct a composite gel electrolyte becomes a key strategy, wherein Metal Organic Frameworks (MOFs) can provide rich ion transport active sites due to the ultra-high specific surface area, and the pore structure is adjustable to realize selective transport of lithium ions, which is regarded as an ideal filler. However, unmodified MOFs have poor electrochemical stability, and active sites in the cycle are prone to irreversible side reactions with electrodes, which affect the long-cycle stability of the battery. Although research attempts are made to perform functional modification on MOFs, the existing functional MOFs-based composite gel electrolyte still has the problems that the ionic conductivity and the cycling stability are difficult to be compatible, the preparation process is complex and the like, and the industrialized application of the functional MOFs-based composite gel electrolyte is limited. Disclosure of Invention In order to solve the defects in the prior art, the invention aims to provide a nitro functional metal organic framework-based composite solid electrolyte, and a preparation method and application thereof. According to the invention, the nitro functional UiO66 (UiO 66-NO 2) is used as a filler, and the polyion liquid is used as a matrix to construct the composite solid electrolyte, so that the ionic conductivity and the migration number of lithium ions can be remarkably improved, the growth of lithium dendrites is inhibited, the interfacial compatibility of the electrode/electrolyte is improved, and the cycling stability of the lithium metal battery is further improved. The solid electrolyte has simple preparation process and low cost, and has wide industrial application prospect. In order to achieve the above object, the present invention is realized by the following technical scheme: in a first aspect, a method for preparing a nitro-functionalized metal-organic framework-based composite solid electrolyte includes the steps of: (1) Carrying out hydrothermal reaction on zirconium salt and nitroterephthalic acid, and centrifugally washing and drying to obtain nitrofunctional metal-organic framework powder; (2) Ion stirring replacement is carried out on chitosan quaternary ammonium