Surface-treated cathode active material for lithium secondary batteries, method for manufacturing the same, cathode for lithium secondary batteries comprising said active material, and lithium secondary battery comprising said cathode

Nickel-rich cathode active material with electrolyte penetration blocked by vapor-deposited silane self-assembled monolayers

This technology forms a self-assembled monolayer (SAM) on the surface of nickel-rich layered oxide cathode active materials via vapor deposition of organic silane compounds, preventing electrolyte penetration into the particles and improving interfacial stability.

Nickel-rich cathode active materials have historically suffered from electrolyte penetration during high-voltage charging, leading to side reactions. This results in gas generation, micro-cracking, and electrode polarization, which limit battery capacity and lifespan.

This technology applies organic silane compounds, such as octyltrichlorosilane (OTS), via vapor deposition to create a 0.1–10 nm thick self-assembled monolayer. The hydrophobic film, anchored by Si-O-Ni covalent bonds, prevents direct contact between the electrolyte and the active material, thereby suppressing particle degradation and micro-cracking. Suitable for long-range EV cells and high-energy drone batteries requiring high-voltage charging, this nanometer-thin film effectively manages both gas expansion and particle cracking.

‍

‍

Key Features:

• Nickel-rich layered oxide represented by the chemical formula LiNixM1yM21-x-yO2, where x is between 0.66 and 0.99
• Self-assembled monolayer formed on the surface of the nickel-rich layered oxide, comprising organic silane compounds
• Si-O-Ni bond structure formed by covalent bonding between surface nickel and the silicon of the organic silane compounds
• Si-O-Si bond sections formed by connecting unreacted silicon of adjacent organic silane compounds

‍