Method for Manufacturing a Separator for Lithium Metal Secondary Batteries and a Lithium Metal Secondary Battery Manufactured Using the Same

Dendrite-Suppressing Lithium Metal Battery Separator Using Vapor-Phase Polymerized Conductive Polymer-Inorganic Thin-Film Coating

This technology forms a conductive polymer-inorganic composite thin-film coating on a porous substrate while maintaining its pores. By applying an oxidizing agent to the substrate and performing vapor phase polymerization with conductive monomers and inorganic precursors, it suppresses lithium dendrite growth and improves the thermal and electrical properties of the separator.

Using lithium metal anodes often leads to internal short circuits caused by uneven lithium dendrite growth. Existing modification methods like sputtering or laminating require complex, vacuum-based processes and often reduce energy density due to the thickness of the coating layers.

This technology involves applying an oxidizing agent, such as an iron-based compound, to the surface and pores of a polyolefin-based porous substrate. It then uses vapor phase polymerization with conductive monomers like pyrrole and inorganic precursors like TEOS or TTIP to create a 10–200nm thin-film coating. Applicable to next-generation high-energy-density batteries and lightweight cells for drones and air mobility, it ensures heat resistance and electrolyte wettability without increasing cell thickness.

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Key Features:

• Applying an oxidizing agent, such as FeCl3, to a polyolefin-based porous substrate while maintaining its pores
• Vapor phase polymerizing a mixture containing conductive monomers and inorganic precursors onto the porous substrate
• A coating layer containing conductive polymer resin and inorganic material, formed with a thickness between 10 nm and 200 nm
• A vapor phase polymerization step performed in an inert gas atmosphere at a temperature between 20 ℃ and 150 ℃

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This invention was developed with support from the Ministry of Science and ICT for target-specific functional dual-sided separator-based lithium metal batteries.

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