Composite nanofiber lithium ion battery diaphragm and preparation method thereof

Abstract

The invention discloses a composite nanofiber lithium ion battery diaphragm and a preparation method thereof. The preparation method comprises the following steps: firstly, adding 1.5-3 parts of a dissolving-assisted salt and 0.5-2.5 parts of p-phenylenediamine into N-methyl-2-pyrrolidone with a water content of less than 100 ppm, stirring in water until the dissolving-assisted salt and the p-phenylenediamine are completely dissolved, then adding paraphthaloyl chloride, keeping stirring for polymerization, preparing a polymer solution with a mass concentration of 10-16% by using acetone or N, N-dimethylformamide as a solvent, uniformly stirring in water at a temperature of 50 DEG C, eliminating bubbles, and standing for 3-5 hours for later use; and coating the surface of a base membrane with the polymer solution by using a coating method. According to the invention, glass fiber filaments are added in a manufacturing process of a lithium ion diaphragm, so that the overall heat insulation performance of the diaphragm can be improved on the original basis; and the structural strength of the diaphragm layer is relatively high, so that external high temperature can be blocked in the application process, lithium ions are prevented from being damaged, and the application range is effectively widened.

Description

technical field [0001] The invention relates to the technical field of battery diaphragm processing, in particular to a composite nanofiber lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] Lithium-ion battery separator is a porous film, its function is to isolate the positive and negative electrodes, prevent the internal short circuit of the battery, and allow the ions in the electrolyte to pass freely between the positive and negative electrodes. The material of the lithium-ion battery separator is mainly porous polymer Films, such as polypropylene (PP), polyethylene (PE), polypropylene / polyethylene / polypropylene (PP / PE / PP) films; non-woven fabrics such as glass fiber non-woven fabrics, synthetic fiber non-woven fabrics, ceramic fibers Paper, etc., and polyolefin material has become a The most widely used diaphragm material, but the existing diaphragm itself does not have good heat insulation performance during use, and the exte...

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