Polyvinylidene fluoride micropore diaphragm

Abstract

The invention discloses a polyvinylidene fluoride micropore diaphragm which is mainly applied to a lithium ion battery. The micropore diaphragm is prepared by a supercritical fluid phase separation method.

Description

technical field [0001] The invention relates to a polyvinylidene fluoride microporous diaphragm, which is mainly used in lithium ion batteries. Background technique [0002] Lithium-ion batteries have been developed rapidly due to their excellent electrical properties such as high energy density, long cycle life and high voltage. Has been widely used in mobile phones, portable computers, cameras, video cameras and other electronic products. Lithium-ion batteries are divided into liquid lithium-ion batteries and solid-state lithium-ion batteries. Solid-state lithium-ion batteries are generally called polymer lithium-ion batteries or plastic lithium-ion batteries. The electrolyte of the ion battery is not a free electrolyte, but a gel electrolyte or a solid electrolyte. Polymer electrolytes not only have high ionic conductivity, long cycle life, minimal pollution and good processing performance, but also have better safety and flexibility in shape design. They are used to re...

AI Technical Summary

Problems solved by technology

The biggest disadvantage of the immersion precipitation method is that it is difficult to obtain a membrane with a symmetrical structure, and finger-shaped holes are prone to appear, which is not conducive to the contact between the separator and the electrode.

In recent years, the thermally induced phase separation method has been studied more. Its advantages are narrow pore size distribution, symmetrical structure, and no finger-like pores. The preparation process needs to use a large amount of solvent, which is easy to cause environmental pollution and other problems