Polypropylene microporous diaphragm

Abstract

The invention discloses a polypropylene microporous diaphragm which is mainly used for a lithium ion battery. The microporous diaphragm is prepared by a supercritical fluid phase separation method.

Description

Technical field [0001] The invention relates to a polypropylene microporous diaphragm, which is mainly used for lithium ion batteries. Background technique [0002] Lithium-ion batteries have achieved rapid development due to their excellent electrical properties such as high energy density, long cycle life and high voltage. It has been widely used in the fields of electronic products such as mobile phones, portable computers, cameras, and video cameras. 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 working principle is the same as that of liquid lithium-ion batteries. The difference is polymer lithium The electrolyte of an ion battery is not a free electrolyte, but a gel electrolyte or a solid electrolyte. Polymer electrolyte not only has high ionic conductivity, long cycle life, minimal pollutio...

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