High-wettability lithium-ion battery separator and preparation method thereof

Abstract

The invention relates to the field of lithium-ion batteries, and discloses a high-wettability lithium-ion battery separator and a preparation method thereof. The separator contains an adhesive component which has high wettability on a lithium-ion battery electrolyte in the surface and the inside. The preparation method comprises the following steps of (1) dissolving an adhesive material into an oily solvent to obtain a mixture I; and (2) coating the surface of a polyolefin separator with the mixture I, immersing the solvent into an internal gap of the separator and then drying to obtain the lithium-ion battery separator with high wettability on the electrolyte. The prepared separator is high in wettability on the electrolyte, low in cost and simple in processing procedure.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a highly wettable lithium ion battery diaphragm and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in digital products, electric tools, electric vehicles and other fields because of their advantages such as high cell voltage, high specific energy and small self-discharge. At present, most of the separators of commercial lithium-ion batteries are made of PP or PE, which are prepared by unidirectional or biaxial stretching. However, since the polyolefin material is non-polar, the wettability of the prepared separator to the electrolyte is poor, which affects the rate performance of the lithium-ion battery, and this also restricts the development of related industries to a certain extent. [0003] In the currently published patents and literatures, the polar modification methods for polyolefin separators mainly include the foll...

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Problems solved by technology

However, there are certain defects in the above two methods. For method one, due to the poor polarity of polyolefin materials, when it is blended with polar materials, it is easy to separate phases, resulting in deterioration of the performance of the separator. For method two, it can only Increased polarity on the surface of the separator without improving the polarity inside the separator

In order to solve the above problems, some researchers choose some polar polymer materials, such as PET, cellulose, etc., to prepare lithium-ion battery separators through non-woven fabric technology. However, the separators prepared by this method have large pore diameters and poor mechanical properties. large discharge

[0004] At present, there are no related reports on the membrane with high wettability both on the surface and inside of the membrane.

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