In the structure of lithium-ion batteries, the diaphragm is one of the key internal components. The performance of the diaphragm determines the interface structure, internal resistance, etc. of the lithium-ion battery, and directly affects the battery's capacity, cycle and safety performance. A diaphragm with excellent performance has an important purpose for improving the overall performance of the battery.

The important purpose of the separator is to separate the positive and negative electrodes of the lithium-ion battery to prevent the two poles from contacting and short-circuit. In addition, it also has the function of allowing electrolyte ions to pass through. The diaphragm material is non-conductive, and its physical and chemical properties have a great influence on the performance of the battery. Different types of batteries have different separators. Regarding the lithium-ion battery series, since the electrolyte is an organic solvent system, a separator material resistant to organic solvents is required. Generally, high-strength thin-film polyolefin porous membranes are used.

Types of lithium ion battery separators

Lithium-ion battery separators can be divided into different types according to their structure and composition. There are currently three important and common types in the market, namely porous polymer membranes, non-woven membranes, and inorganic composite membranes.

1. Porous polymer membrane

It refers to a lithium-ion battery separator with an even pore distribution prepared by mechanical methods, thermally induced phase separation methods, immersion precipitation methods and other methods.

2. Non-woven diaphragm

It is composed of oriented or random fibers, and is usually combined with organic matter or ceramic gel to obtain lithium-ion battery separators with better chemical and physical properties.

3. Inorganic composite membrane

Most of them are lithium-ion battery separators obtained by compounding inorganic nanoparticles and high polymers.