What conditions of polymer electrolyte lithium ion battery diaphragm needs to meet ?

In recent years, the use of polymer electrolytes in lithium ion batteries has been commercialized. Polymer electrolytes are both ion transfer channels in lithium ion batteries and play a diaphragm role between positive and negative electrode materials. Polymer electrolytes can be divided into solid polymer electrolytes and gel polymer electrolytes. As a practical polymer electrolyte diaphragm, the following necessary conditions must be met:

1 has a high Ionic conductivity to reduce the internal resistance of the battery;

The transfer coefficient of lithium ions is basically unchanged to eliminate concentration polarization;

3 Neglected electron conductivity to ensure effective isolation between electrodes;

4 Electrode materials have high chemical and electrochemical stability;

Cheap prices and proper chemical composition ensure environmental friendliness.

Due to the low room temperature conductivity of solid polymer electrolytes, it is difficult to commercialize. Gel polymer electrolytes achieve Ionic conduction through liquid electrolyte molecules fixed in polymer networks. Both the stability of solid polymers and the high Ionic conductivity of liquid electrolytes show good application prospects.

Polymer electrolytes are combined with polyethylene and polyacrylate membranes to form polymer lithium-ion battery membranes, and colloidal polymers are covered or filled in microporous membranes. Compared with non-diaphragm polymer electrolyte lithium-ion batteries, they have superior properties., such as:

1 provides better protection when the internal short circuit;

The thickness of the electrolyte layer can be reduced;

3 provides sufficient safety when overcharging;

4 It has better mechanical properties and thermal stability. It can be seen that polyethylene and polyacrylate membranes occupy an important position in the ion battery diaphragm due to their special structure and properties, unless there is a real liquid free polymer electrolyte.

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