Oyster shell-coated separator for lithium secondary batteries, manufacturing method thereof, and lithium secondary battery comprising the same

Lithium Metal Battery Separator with Dendrite Suppression via Oyster Shell CaCO3 Coating

This technology involves coating the surface of a polyethylene (PE) separator with a mixture of pulverized oyster shell powder—primarily composed of calcium carbonate (CaCO3)—and a PVDF binder. This process enhances the physical rigidity and hydrophilicity of the separator, effectively suppressing lithium dendrite growth.

Lithium metal batteries (LMBs) have historically faced issues with rapid lithium dendrite growth leading to internal short circuits. Furthermore, continuous electrolyte decomposition and thermal shrinkage of the separator at high temperatures have limited battery safety.

This technology forms a 2.0μm-thick coating layer on the PE separator surface by blade-casting a slurry made from pulverized oyster shells (containing CaCO3 and CaO). The coating improves thermal stability, electrolyte absorption, and wettability, while reducing side reactions at the lithium metal interface to ensure cycle life and safety. It is applicable to high-energy lithium metal batteries and lightweight cells for drones and wearables, contributing to an eco-friendly supply chain by recycling marine waste into low-cost ceramic materials.

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Key Features:

• Lithium secondary battery separator containing hydrophilic oyster shells and coated with oyster shells on the surface
• Coating layer containing calcium carbonate (CaCO3) and calcium oxide (CaO) derived from oyster shells as elements constituting the upper layer of the separator
• Step of preparing an oyster shell-containing slurry by adding pulverized oyster shells to a solution containing a binder and a solvent
• Step of coating the separator surface with oyster shells by blade-casting the oyster shell-containing slurry onto the separator

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