Separator is one of the four key components of lithium ion battery. The separator is not directly involved in the internal reaction of Li ion battery,but its structure and properties directly affect the capacity of the battery,circulation and safety.However, due to the low melting point of polyolefin material itself (PE about 135 ℃,PP about 165℃) and the drawing process is included in the preparation process, the diaphragm is easy to shrink and melt at high temperature. Eventually, it leads to safety accidents. In addition, the non-polar polyolefin membrane is difficult to be infiltrated by the polar organic electrolyte,the pores in the diaphragm cannot be filled with electrolyte.This leads to an increase in diaphragm impedance. Finally, it affects the cycle and rate performance of the battery. These disadvantages of polyolefin separator hinder the further application of lithium ion battery in many fields.

         ●   Separators are electrochemically inactive thin porous membranes that physically separate the cathode from the anode, while allowing ion transport to occur.

         ●   Separator shutdown above the melting point seeks to prevent thermal runaway by stopping ion flow between the cathode and anode, but separator breakdown at even higher temperatures can lead to thermal runaway.

         ●   Ceramic-coated separators and high melting point polymer materials are promising candidates due to their improved thermal stability and tolerance for abuse, but further development is still needed for increased safety and reliability.

        In view of these shortcomings of polyolefin membrane,Polyvinylidene fluoride(PVDF) as a binder, it is widely used in electrode manufacturing process and diaphragm coating process of lithium ion battery. However PVDF has a lower melting point(115～170℃), When the outside temperature is close to the melting point of the adhesive，the adhesive melts and cannot effectively adhere to the inorganic particles. In order to improve the thermal stability of diaphragm at higher temperature，more and more attention has been paid to the application of new adhesives in the coating process of lithium-ion battery separators. These high melting point binders can effectively adhere to inorganic particles at higher temperatures . But these adhesives don't work in the electrolyte like PVDF and swelling occurs in the electrolyte，Improve adhesion and ionic conductivity. Therefore, the use of this kind of high melting point adhesive can improve the thermal stability of ceramic coated diaphragm at higher temperature,But often at the cost of reducing the electrochemical performance of the battery .

        The solution of Seperator Coating Binder of Lovachem.

        Lova Froce A Series