Surface treatment method for lithium secondary battery cathode active materials via simple stirring

Surface treatment of LiCoO2 without heat treatment by coating with a CuCoO2 film via room-temperature copper ion exchange

This technology forms a spinel-structured CuCoO2 film on the surface of lithium cobalt oxide (LiCoO2) particles without high-temperature heat treatment by dispersing and stirring the particles in a copper nitrate (Cu(NO3)2) aqueous solution to replace surface lithium with copper ions.

When operated at high voltages, LiCoO2 suffers from structural collapse and accelerated side reactions with the electrolyte, leading to a shortened lifespan. Conventional inorganic coatings used to prevent this require high-temperature heat treatment above 700°C, which limits process cost and energy efficiency.

This technology suppresses electrochemical side reactions by forming a 3–4 nm thin CuCoO2 or CuO coating layer on the LiCoO2 surface through simple room-temperature stirring. It can be applied to mass production lines for smartphone and laptop LCO cells requiring high-voltage operation, offering an economical solution by adding a surface modification process using only an aqueous reaction tank, without the need for additional firing furnaces.

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Key Features:

• Dispersing and stirring layered lithium cobalt oxide cathode active material in an aqueous copper(II) nitrate solution
• Replacing lithium within the cathode active material structure with copper elements from the solution to form a CuCoO2 film on the particle surface
• A stirring step performed for 6 to 144 hours to facilitate the copper substitution reaction without separate heat treatment
• A CuCoO2 film on the cathode active material surface, featuring a spinel-like structure and a thickness of 3–4 nm

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