Research and Development

Separators for Lithium-ion Batteries

Innovative Separator LIELSORT®


With the growing popularization of tablet PCs and electric vehicles, lithium-ion batteries (LIBs) are expected to achieve both of larger capacity and higher energy density. LIELSORT electrically isolates the cathode from the anode to inhibit thermal runaway caused by short circuits and contributes high voltage stability and finally consumer safety. 

Cylindrical-type battery

Laminated-type battery


In responding to increasingly evolving and diversified market needs, Teijin developed LIELSORT, innovative separators using microporous polyethylene substrate, one coated with Teijinconex meta-aramid, and the other coated with the world's first fluorine-based compound, for superior heat-resistance and adhesion to polymer electrolyte.

Longer Battery Life as well as 20% Higher Output

The separator coated with Teijinconex meta-aramid maintains its shape even at 250℃. In spot heating tests, Teijin has verified that the separator does not break down even at 400℃. This superior heat-resistance persistently inhibits thermal runaway, enabling LIB production with greater safety.

Another type is fluoride coated separator. It has been designed for pouch-type of LIBs used for tablet PCs and smartphones for instance. This separator has excellent adhesion to electrodes and prevents leakage of electrolyte, resulting in a LIB with higher reliability and longer lifespan.

These two types of innovative separator LIELSORT products give superior resistance to oxidation and high affinity / wettability with electrolyte. LIELSORT may combine with a high-potential cathode and contribute LIB safety and lifespan liability.

Functionality of Innovative Separator LIELSORT®