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Functional diaphragm as well as preparation method and application thereof

A membrane and functional technology, applied in the field of functional membrane and its preparation, to achieve the effects of easy scale, improved safety and stability, and improved transmission

Active Publication Date: 2022-03-15
YUNNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The anionic covalent organic framework (COF) in the functional separator provided by the present invention inhibits the transmission of lithium salt anions through electrostatic interaction, while the open one-dimensional nanopores of COF ensure the rapid transmission of lithium ions in the battery. Lithium dendrite problem solved

Method used

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  • Functional diaphragm as well as preparation method and application thereof
  • Functional diaphragm as well as preparation method and application thereof
  • Functional diaphragm as well as preparation method and application thereof

Examples

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preparation example Construction

[0069] The present invention also provides a method for preparing the functional diaphragm described in the above technical solution, comprising the following steps:

[0070] Mixing an anionic covalent organic framework, polyvinylidene fluoride (PVDF) and N-methylpyrrolidone (NMP) to obtain a slurry;

[0071] The slurry is coated on the surface of the membrane to obtain the functional membrane.

[0072] The invention mixes the anion-containing covalent organic framework, polyvinylidene fluoride and N-methylpyrrolidone to obtain the slurry.

[0073] In the present invention, the mixing is preferably carried out under the condition of magnetic stirring, the time of magnetic stirring is preferably 6-12 hours, and the rotation speed is preferably 200-300 rpm.

[0074] After the slurry is obtained, the present invention coats the slurry on the surface of the membrane to obtain the functional membrane.

[0075] In the present invention, the coating is preferably applied with a doc...

Embodiment 1

[0081] An anionic covalent organic framework modified functional membrane (COF-COOH@PP), specifically comprising the following steps:

[0082] Step 1: The monomer 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde (63.0 mg) and 4,4'-diamino-1,1'-biphenyl-3,3'- Dicarboxylic acid (122.5 mg) was mixed in a hard ampoule, and 1,4-dioxane (1 mL) and 1,3,5-trimethylbenzene (3 mL) were added to the ampoule at a volume ratio of 1:3 ), the ampoule bottle containing the mixed solution was ultrasonically mixed for 10 minutes to mix the above solutions evenly; after adding 0.6 mL of 6M acetic acid aqueous solution dropwise to the solution, the ampoule bottle containing the mixed solution was placed in liquid nitrogen to freeze. In order to get rid of excess air and moisture in the ampoule that could affect the reaction, the ampoule was subjected to three repetitions of vacuuming-thawing-freezing. After the impurities are exhausted, the oil pump is used to evacuate again, and the vacuum is seal...

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Abstract

The invention provides a functional diaphragm as well as a preparation method and application thereof, and belongs to the technical field of lithium metal battery diaphragms. The invention provides a functional diaphragm which comprises a diaphragm and a compact modification layer which are stacked, and the compact modification layer contains an anionic covalent organic framework and polyvinylidene fluoride. According to the anionic covalent organic framework modified functional diaphragm provided by the invention, COF in the anionic COF compact modification layer can hinder shuttling of lithium salt anions through electrostatic interaction, so that the nucleation time of lithium dendrites is prolonged, and the safety and stability of a battery are improved; and by utilizing the one-dimensional nano open pore channel of the COF, the lithium ion transmission of the compact modification layer can be obviously improved, and the lithium ion transference number and the cycle performance of the battery are improved.

Description

technical field [0001] The invention relates to the technical field of diaphragms for lithium metal batteries, in particular to a functional diaphragm and its preparation method and application. Background technique [0002] In lithium metal batteries, due to the high activity of lithium metal electrodes and poor chemical / electrochemical stability, lithium dendrites are easily formed during the continuous lithium deposition / stripping process, which destroys the solid electrolyte interface (SEI) film and aggravates side reactions. , so as to continuously consume the lithium metal negative electrode, and even produce "dead lithium", which eventually leads to a decrease in Coulombic efficiency, resulting in irreversible capacity loss and deterioration of battery cycle performance. In more serious cases, the dendrites will also pierce the separator and make the positive and negative electrodes contact, causing the battery to short circuit, resulting in thermal runaway, causing t...

Claims

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Application Information

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IPC IPC(8): H01M50/449H01M50/426H01M50/403H01M10/052
CPCH01M50/449H01M50/426H01M50/403H01M10/052Y02E60/10
Inventor 郭洪安琪孙勇疆赵根福
Owner YUNNAN UNIV