Protective layer for secondary battery cathodes and manufacturing method thereof

Cathode protective coating that preserves both initial capacity and cycle life using aluminum-doped zinc oxide thin films

This technology involves coating the surface of a lithium-ion battery cathode active material with an aluminum-doped zinc oxide (AZO) thin film, represented as Al(2/3)xZnxO (x=0.05~0.2), at a thickness of 1–10 nm. This prevents the formation of irreversible lithium secondary phases during charge/discharge cycles and ensures long-term stability.

Conventional oxide-based cathode protective layers often suffer from low electrical conductivity, which can degrade the electrical performance of the cathode. Furthermore, the limited range of materials compatible with atomic layer deposition (ALD) processes has historically made it difficult to achieve optimal cathode performance.

This technology utilizes Al(2/3)xZnxO—zinc oxide doped with aluminum—as a protective layer material. By forming a uniform 1–10 nm thin film via ALD, CVD, or sputtering, it allows for precise control over the physical and electrical properties of the cathode surface. It can be applied to the surface treatment of various commercial cathode materials, including NCM, LCO, LMO, and LFP, serving as a coating solution that minimizes initial capacity loss while significantly improving long-term cycle capacity retention.

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Key Features:

• A protective layer disposed on a secondary battery cathode, represented by the composition Al(2/3)xZnxO where x is between 0.05 and 0.2
• A cathode protective layer formed with a thickness of 1 nm to 10 nm to simultaneously improve initial capacity and capacity retention
• A step of forming a protective layer by depositing zinc oxide on a secondary battery cathode followed by aluminum doping
• A step performed via atomic layer deposition, chemical vapor deposition, or sputtering, involving doping through aluminum oxide deposition

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