Surface coating method using elemental materials for lithium secondary battery oxides

Cathode surface treatment method for forming a uniform coating layer using elemental material sublimation heat treatment

This technology involves mixing lithium transition metal oxides with elemental materials such as sulfur (S) or phosphorus (P), followed by heat treatment at the sublimation temperature of the elemental material (150–600°C) to form a uniform compound coating layer on the surface of the active material.

Layered lithium transition metal oxides (particularly high-nickel types) have historically suffered from reduced cycle life and capacity retention due to side reactions with electrolytes during high-voltage charging and discharging, phase transitions caused by surface nickel exposure, and subsequent structural instability.

By utilizing elemental materials like sulfur (S) to form a compound-based protective layer on the cathode active material surface through a sublimation process, this technology can be effectively used to enhance the efficiency of secondary battery manufacturing processes.

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Key Features:

• A step of uniformly mixing an elemental material consisting of sulfur with a lithium transition metal oxide
• A step of heat-treating the mixture at 150 to 400°C, the sublimation temperature of sulfur, for at least 2 hours
• A step of forming a uniform coating layer composed of a compound of the elemental material on the surface of the lithium transition metal oxide through heat treatment
• A configuration that forms a compound coating layer on the surface of the active material by heat-treating at the sublimation temperature of elemental materials such as sulfur or phosphorus

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