Separator coating composition containing lithium p-toluenesulfinate, a separator using the same, and a rechargeable battery comprising the same

200°C Heat-Resistant Polyimide Separator with Integrated Artificial CEI PTSL Coating

This technology enhances the thermal stability of polyimide (PI) separators by coating their surfaces with lithium p-toluenesulfinate (PTSL) particles and a binder. The coating layer acts as an artificial Cathode Electrolyte Interphase (CEI) at the cathode interface, suppressing electrolyte side reactions.

Conventional polyethylene (PE) separators shrink at around 130°C, posing risks of internal short circuits and cell explosions at high temperatures. Furthermore, using high-energy-density cathodes, such as Ni-rich NCM, often leads to reduced cycle life due to side reactions with the electrolyte.

This technology involves applying PTSL with a polymer binder onto one or both sides of a porous support to form a coating layer. The sulfonate (SOx) functional group of PTSL functions as an artificial CEI layer that inhibits electrolyte decomposition, improves separator wettability and ion conductivity, and provides heat resistance exceeding 200°C. It can be applied to EV cells using high-nickel cathodes and power tool batteries prone to overheating during fast charging, solving both thermal safety and cathode interface protection challenges simply by replacing the separator.

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Key Features:

• Separator coating composition comprising lithium p-toluenesulfinate, a polymer binder, and a solvent
• Rechargeable battery separator formed by coating lithium p-toluenesulfinate on one or both sides of a porous support
• Separator coated with lithium p-toluenesulfinate exhibiting a Gurley value of 11.5 seconds/100 cc of air
• Lithium p-toluenesulfinate coating layer that maintains thermal stability up to 200°C and improves electrolyte absorption

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