Functional diaphragm for lithium-sulfur battery as well as preparation method and application of functional diaphragm

A lithium-sulfur battery and a functional technology are applied in the field of functional separators for lithium-sulfur batteries and their preparation, which can solve the problems of capacity reduction, impact on battery performance, low ionic conductivity, etc., to prevent the formation of polysulfides, improve Lithium ion migration number and the effect of improving ionic conductivity

Pending Publication Date: 2021-08-03
HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The "shuttle effect" leads to the loss of lithium polysulfide from the positive electrode, which reduces the active material and reduces the utilization rate of sulfur, resulting in a decrease in capacity
The pore structure of traditional lithium battery separators cannot effectively block the shuttle of lithium polysulfide. In addition, the shortcomings of traditional separators such as hydrophobicity, low polarity, and low surface energy lead to low liquid absorption and poor liquid retention of the separator, which in turn leads to low ion conductivity. , affecting battery performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A preparation method of a functional separator for a lithium-sulfur battery, comprising the following steps:

[0036] Coating the first slurry on the positive side of the base film to obtain a first coating on the base film, coating the second slurry on the negative side of the base film and forming a second coating to obtain the function for lithium-sulfur batteries The coating method is roller coating, the thickness of the first coating layer is 2 microns, the thickness of the second coating layer is 2 microns, and the base film is a polyethylene film.

[0037] The preparation method of the first slurry is as follows: mixing a dispersant with a first solvent, the dispersant being 5 wt % of the first solvent, stirring for 20 minutes until uniform, then adding a carbon-based conductor and a first binder, stirring for 20 minutes until uniform, Sand milled for 20min to obtain the first slurry, in terms of parts by mass, the ratio of the carbon-based conductor and the firs...

Embodiment 2

[0040] A preparation method of a functional separator for a lithium-sulfur battery, comprising the following steps:

[0041] Coating the first slurry on the positive side of the base film to obtain a first coating on the base film, coating the second slurry on the negative side of the base film and forming a second coating to obtain the function for lithium-sulfur batteries The coating method is roller coating, the thickness of the first coating layer is 2.5 microns, the thickness of the second coating layer is 2 microns, and the base film is a polyethylene film.

[0042] The preparation method of the first slurry is as follows: mixing a dispersant with a first solvent, the dispersant being 5 wt % of the first solvent, stirring for 30 minutes until uniform, then adding the carbon-based conductor and the first binder, stirring for 30 minutes until uniform, Sand milled for 36 minutes to obtain the first slurry, in terms of parts by mass, the ratio of the carbon-based conductor a...

Embodiment 3

[0045] A preparation method of a functional separator for a lithium-sulfur battery, comprising the following steps:

[0046]Coating the first slurry on the positive side of the base film to obtain a first coating on the base film, coating the second slurry on the negative side of the base film and forming a second coating to obtain the function for lithium-sulfur batteries A separator, wherein the coating method is roll coating, the thickness of the first coating layer is 3 microns, the thickness of the second coating layer is 2 microns, and the base film is a polypropylene film.

[0047] The preparation method of the first slurry is as follows: mixing a dispersant with a first solvent, the dispersant being 5 wt % of the first solvent, stirring for 40 minutes until uniform, then adding a carbon-based conductor and a first binder, stirring for 40 minutes until uniform, Sand milled for 40 minutes to obtain the first slurry. In terms of parts by mass, the ratio of the carbon-base...

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PUM

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Abstract

The invention discloses a functional diaphragm for a lithium-sulfur battery as well as a preparation method and application of the functional diaphragm, and the preparation method comprises the following steps: coating the positive electrode side of a base membrane with first slurry to obtain a first coating on the base membrane, and coating the negative electrode side of the base membrane with second slurry to form a second coating to obtain the functional diaphragm for the lithium-sulfur battery, wherein a preparation method of the first slurry comprises the following steps: mixing a dispersing agent and a first solvent, performing uniform stirring, adding a carbon conductor and a first binder, performing uniform stirring, and and performing sanding to obtain the first slurry; a preparation method of the second slurry comprises the following steps: adding unsaturated carboxylic acid and a second binder into a second solvent, and performing uniform stirring to obtain the second slurry, the unsaturated carboxylic acid being olefine acid. According to the preparation method, the ionic conductivity of the diaphragm can be improved, and battery polarization can be reduced, so the rate capability of the battery is improved.

Description

technical field [0001] The invention belongs to the technical field of battery separators, and in particular relates to a functional separator for lithium-sulfur batteries and a preparation method and application thereof. Background technique [0002] Lithium-sulfur batteries have the advantages of high energy density, high theoretical capacity, etc. In addition, the characteristics of abundant raw materials and low cost have also promoted the rapid growth of their market. However, lithium-sulfur batteries still have the problems of poor battery cycle performance, low rate performance, and poor safety and stability performance, which are closely related to the characteristics of the battery separator. [0003] The power lithium-ion battery is mainly composed of a positive electrode, a negative electrode, an electrolyte, a diaphragm and a shell. The separator plays a role in blocking the electron conductance of the positive and negative electrodes in the battery, allowing th...

Claims

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Application Information

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IPC IPC(8): H01M50/403H01M50/417H01M50/446H01M50/451H01M50/457H01M10/052
CPCH01M10/052Y02E60/10
Inventor 袁海朝徐锋苏柳苏碧海
Owner HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
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