Polyimide-based separator containing zirconium oxide, method for manufacturing the same, and lithium secondary battery comprising the same

High-Safety Polyimide Separator with Pore-Sealing ZrO2-TNP Composite Dip-Coating

This technology forms a coating layer containing a composite of nano-sized zirconium oxide (ZrO2) and the free radical scavenger tri-1-naphthylphosphine (TNP) to seal the large pores of polyimide (PI) separators and ensure safety.

While polyimide separators offer excellent thermal stability, their inherent porous structure often fails to sufficiently separate the anode and cathode during battery assembly, leading to internal short circuits and current leakage.

This technology involves dispersing ZrO2 and TNP in a PVdF-HFP binder solution and applying it to the PI separator surface via dip-coating to seal the pores. By coating at least 6.44 mg/cm² of the ZrO2-TNP composite, it prevents internal shorts, while the radical scavenging function of TNP enhances thermal properties at high temperatures. It can be applied to NCM811-based high-nickel EV batteries or energy storage cells exposed to high heat, fundamentally reducing the risk of internal shorts that could lead to thermal runaway.

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Key Features:

• Zirconium oxide (ZrO2) and tri-1-naphthylphosphine (TNP) composite that seals pores when dip-coated onto polyimide-based separators
• Tri-1-naphthylphosphine (TNP) additive that forms the separator coating composite and acts as a free radical scavenger
• Step of preparing the composite by dispersing zirconium oxide (ZrO2) and tri-1-naphthylphosphine (TNP) in a binder solution
• Step of dip-coating the polyimide-based separator in the composite dispersion solution to coat the surface

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