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CN-122011499-A - Preparation method of in-situ growth ZIF-71 polypropylene composite membrane and application of in-situ growth ZIF-71 polypropylene composite membrane in nonaqueous flow battery

CN122011499ACN 122011499 ACN122011499 ACN 122011499ACN-122011499-A

Abstract

The invention relates to a composite membrane of a zeolite imidazole ester frame (ZIF-71) and a polypropylene (PP) membrane in a metal organic frame, a preparation method and application thereof in a nonaqueous flow battery, belongs to the technical field of flow batteries, and provides a ZIF-71/PP composite membrane with different surface morphologies, which is prepared by different in-situ growth methods, and has in-situ grown 2-nitroimidazole zinc zeolite imidazole ester frame layers with different morphologies, so that active substances are effectively blocked from crossing and stringing in the nonaqueous flow battery. In addition, the superior performance of nonaqueous flow batteries demonstrates that composite separators of metal-organic frameworks and polypropylene can maintain structural integrity during prolonged operation in the organic environment.

Inventors

  • XU ZHI
  • HUANG KANG
  • Gai Pizhu

Assignees

  • 南京工业大学

Dates

Publication Date
20260512
Application Date
20260210

Claims (10)

  1. 1. The in-situ grown ZIF-71/polypropylene composite membrane is characterized by comprising a polypropylene porous base membrane and a ZIF-71 selective layer which is grown in-situ at the interface of the polypropylene porous base membrane, wherein the ZIF-71 selective layer consists of compact ZIF-71, and the thickness of the ZIF-71 selective layer is 1-2 mu m.
  2. 2. The in situ grown ZIF-71/polypropylene composite membrane of claim 1, wherein the ZIF-71 selective layer has a microscopic morphology of blocks or flower spheres.
  3. 3. The in-situ grown ZIF-71/polypropylene composite film according to claim 1, wherein the electrolyte contact angle of the composite film is 20-40 °, preferably 20-30 °, and the swelling ratio of the composite film in an organic solvent is 3-10%, preferably 3-6%.
  4. 4. The in situ grown ZIF-71/polypropylene composite membrane of claim 1, wherein the composite membrane has a permeability to 10-methylphenothiazine of less than 7.78 x 10 -10 cm 2·s-1 and/or a permeability to 2,1, 3-benzothiadiazole of less than 1.61 x 10 -9 cm 2·s-1 .
  5. 5. A preparation method of an in-situ growth ZIF-71/polypropylene composite membrane according to any one of claims 1-4 is characterized by comprising the steps of preparing zinc source solution and ligand solution respectively, immersing a polypropylene porous base membrane in a solvent for pretreatment, placing the pretreated polypropylene porous base membrane in a diffusion device, adding the zinc source solution and the ligand solution into two side spaces separated by the diffusion device respectively, performing diffusion reaction under the controlled temperature and humidity conditions, and growing a ZIF-71 selective layer on the surface of the polypropylene porous base membrane in situ, taking out the membrane after the reaction is finished, and drying to obtain the in-situ growth ZIF-71/polypropylene composite membrane.
  6. 6. The preparation method according to claim 5, wherein in the first step, the zinc source solution is a methanol solution of anhydrous zinc acetate, the ligand solution is a methanol solution of 4, 5-dichloroimidazole, and in the second step, the solvent is anhydrous methanol.
  7. 7. The method according to claim 6, wherein in the first step, the concentration of the methanol solution of the anhydrous zinc acetate is 0.9-1.8 mg/mL, or 0.005-0.01 mol/L, the concentration of the methanol solution of the 4, 5-dichloroimidazole is 1.4-6.8 mg/mL, or 0.01-0.05 mol/L, and the molar ratio of the anhydrous zinc acetate to the 4, 5-dichloroimidazole is 1 (2-5), preferably 1 (3.5-4.5).
  8. 8. The method according to claim 5, wherein in the third step, the diffusion device is an H-type diffusion cell, the ambient temperature of the diffusion reaction is 20-40 ℃, preferably 25-30 ℃, the ambient humidity of the diffusion reaction is 30-70% RH, preferably 35-50% RH, and the time of the diffusion reaction is 12-48H.
  9. 9. The method according to claim 5, wherein the third step further comprises stirring the solution at a rotation speed of 100-300 r/min, and the fourth step has a drying temperature of 60-80 ℃, preferably 60-65 ℃.
  10. 10. Use of the in-situ grown ZIF-71/polypropylene composite membrane of any one of claims 1-4 in a nonaqueous flow battery.

Description

Preparation method of in-situ growth ZIF-71 polypropylene composite membrane and application of in-situ growth ZIF-71 polypropylene composite membrane in nonaqueous flow battery Technical Field The invention relates to an in-situ grown zeolite imidazole ester frame (ZIF-71) polypropylene composite membrane with two different morphologies, a preparation method and application thereof in a non-aqueous flow battery, and belongs to the technical field of flow batteries. Background The large-scale utilization of intermittent energy sources such as solar energy, wind energy and the like is in need of a matched large-capacity energy storage technology to realize supply and demand balance. Flow batteries, particularly Vanadium Flow Batteries (VFB), are extremely potential grid-level energy storage technologies. However, the development of vanadium redox flow batteries is limited by high material costs and relatively low energy density (typically 25-30Wh seed L-1). In contrast, the non-aqueous flow battery (NAFBs) has a wider electrochemical stability window (up to 4V, 1.5V for far-aqueous systems) and a richer material selection space, with significant advantages in the high energy density energy storage field. The membrane is used as a core component of the flow battery, and has the dual functions of inhibiting cross permeation of active substances and promoting rapid transmission of charge carriers, so that the membrane becomes a research hot spot. However, the development of nonaqueous flow battery separators faces many challenges, and such separators are required to simultaneously meet the stringent requirements of excellent organic solvent resistance, high ionic conductivity of an organic solvent phase, low permeability of active materials, and the like. In addition, the non-aqueous electrolyte has inherent defects of high viscosity, poor ionic conductivity and the like, and further aggravates the difficulty in realizing the requirements. Currently, commercial polyolefin separators such as Celgard, fumasep are widely used in nonaqueous systems, but such separators generally have problems of insufficient ion selectivity or easy swelling in organic solvents. Therefore, the preparation has excellent organic solvent resistance and low active material permeability, and is important to promote the technical development of the nonaqueous flow battery. Disclosure of Invention The nonaqueous flow battery (NAFBs) requires that the separator have excellent stability against organic solvents and high permeability of active materials in the organic solvent phase to withstand the inherent corrosive effects of nonaqueous electrolyte. Aiming at the technical problem of low selectivity caused by severe crossing of non-aqueous flow battery diaphragm active substances, the invention designs the ZIF-71/PP composite membrane with the ZIF-71 selective layer with excellent organic solvent resistance and low active substance permeability through in-situ growth. Through the compact selective layer of ZIF-71, effective screening of active substances is effectively realized, and the organic-philic solvent ZIF-71 formed on the surface of PP has good electrolyte wettability, so that the service life of the battery is remarkably prolonged. The in-situ growth ZIF-71/polypropylene composite membrane comprises a polypropylene porous base membrane and a ZIF-71 selective layer which is in-situ grown at the interface of the polypropylene porous base membrane, wherein the ZIF-71 selective layer consists of compact ZIF-71, and the thickness of the ZIF-71 selective layer is 1-2 mu m. The micro morphology of the ZIF-71 selective layer is blocky or flower-spherical. The electrolyte contact angle of the composite film is 20-40 degrees, preferably 20-30 degrees, and the swelling rate of the composite film in an organic solvent is 3-10%, preferably 3-6%. The composite membrane has a permeability to 10-methylphenothiazine of less than 7.78X10 -10 cm2·s-1 and/or a permeability to 2,1, 3-benzothiadiazole of less than 1.61X 10 -9 cm2·s-1. The preparation method of the in-situ growth ZIF-71/polypropylene composite membrane comprises the following steps of preparing a zinc source solution and a ligand solution respectively, soaking a polypropylene porous base membrane in a solvent for pretreatment, placing the pretreated polypropylene porous base membrane in a diffusion device, adding the zinc source solution and the ligand solution into two separated side spaces of the diffusion device respectively, carrying out diffusion reaction under the controlled temperature and humidity conditions, and taking out the membrane after the reaction is finished, and drying to obtain the in-situ growth ZIF-71/polypropylene composite membrane. In the first step, the zinc source solution is a methanol solution of anhydrous zinc acetate, the ligand solution is a methanol solution of 4, 5-dichloroimidazole, and in the second step, the solvent is anhydrous methanol. In the first