A kind of preparation method of modified diaphragm for lithium battery

A technology for lithium batteries and separators, which is applied in the field of preparation of modified separators for lithium batteries, can solve the problems that ion selectivity cannot be significantly improved, the thickness of polyolefin separators is increased, the performance of lithium batteries is affected, and the like, and the flying shuttle is suppressed. effect, improved wettability and fluid retention, excellent selectivity

Active Publication Date: 2020-11-03
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although these methods can effectively improve the wettability, liquid retention and heat resistance of commercial polyolefin separators, the effect after modification is still not good, for example, the ion selective passability cannot be significantly improved
In addition, the above modification method will significantly increase the thickness of the polyolefin separator and destroy the original structure of the pores, thereby affecting various performances of the lithium battery.

Method used

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  • A kind of preparation method of modified diaphragm for lithium battery
  • A kind of preparation method of modified diaphragm for lithium battery
  • A kind of preparation method of modified diaphragm for lithium battery

Examples

Experimental program
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Effect test

Embodiment 1

[0033] Positive electrode preparation process: The mass ratio of the slurry is mixed according to the mass ratio of sulfur: acetylene black: polytetrafluoroethylene = 90:5:5, and a 1×1 cm positive electrode is made on an aluminum sheet, and the prepared positive electrode is placed in a certain temperature for vacuum drying Dry at constant temperature in the box for more than 24 hours, and metal lithium is the negative electrode.

[0034] The preparation process of the modified diaphragm for lithium-sulfur batteries: the polyolefin diaphragm is ultrasonically cleaned for a certain period of time using acetone as the solvent, and then placed in a vacuum drying oven at a certain temperature to dry at a constant temperature for more than 24 hours, and the cleaned polyolefin diaphragm is single-sided Corona treatment (Corona Treating), the treatment time is 40 seconds, and the treated diaphragm is exposed to the air for 20 minutes.

[0035] Immerse the treated polyolefin separator...

Embodiment 2

[0037] The operation is the same as in Example 1, except that the cleaned polyolefin membrane is subjected to single-side plasma processing (Plasma Processing).

Embodiment 3

[0039] The operation was the same as in Example 1, except that the polyolefin separator was subjected to single-side corona treatment (Corona Treating), the treatment time was 80 seconds, and the treated separator was exposed to air for 20 minutes. A lithium-sulfur battery is assembled according to the positive electrode / separator / negative electrode.

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Abstract

The invention discloses a method for preparing a modified diaphragm for lithium batteries, comprising the following steps: S1. subjecting the battery diaphragm to corona or plasma treatment; S2. adding the treated battery diaphragm in S1 to an anionic polymer solution modified to obtain the modified separator for the lithium battery; the modified separator of the present invention can effectively inhibit the passage of anions and increase the number of migration of cations, especially in lithium-sulfur batteries, the modified separator can effectively Inhibit the "flying shuttle effect" that occurs during the cycle of lithium-sulfur batteries, and inhibit the attenuation of lithium-sulfur battery capacity. The modified diaphragm provided by the present invention has the advantages of high ion selectivity, simple preparation process and low economic cost, and is suitable for the development of high-performance lithium batteries (such as power lithium batteries, lithium-sulfur batteries, lithium cobalt oxide batteries, lithium manganate batteries and phosphoric acid lithium batteries) Lithium batteries, etc.) provide an effective way to improve.

Description

technical field [0001] The invention belongs to the technical field of battery separators, and more specifically relates to a preparation method of a modified separator for lithium batteries. Background technique [0002] In the structure of commercial lithium batteries, the separator is a very important part. In the battery, it mainly plays the role of isolating the positive and negative electrodes, passing lithium ions, and blocking electrons. Therefore, the charge and discharge capacity, cycle life, and safety performance of lithium batteries are all related to Diaphragms are closely related. [0003] The current commercial separators are mainly polyolefin separators, which use polyethylene (PE) and polypropylene (PP) as the main raw materials, and are produced by dry or wet processes. Polyolefin separators are roughly divided into single-layer polyethylene (PE) Diaphragm, single-layer polypropylene (PP) diaphragm, three-layer PP / PE / PP composite diaphragm. Both polyethy...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M50/403H01M50/411
CPCH01M50/403H01M50/411Y02E60/10
Inventor 黄逸夫王贤宏阮文红章明秋容敏智
Owner SUN YAT SEN UNIV
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