Cathode material for lithium secondary batteries containing N,N,N,N-tetraethylsulfamide, its manufacturing method, and a lithium secondary battery comprising the same

High-Nickel Cathode Materials with Amine/Sulfone-Functionalized Artificial CEI Formed via NTESA Heat Treatment Modification

This technology improves interfacial stability by mixing N,N,N,N-tetraethylsulfamide (NTESA) with cathode active materials and applying heat treatment to form an artificial Cathode-Electrolyte Interphase (CEI) layer functionalized with amine and sulfone groups on the cathode surface.

Due to their high nickel content, Ni-rich NCM cathode active materials generate Ni4+ species during charging, which accelerate electrolyte decomposition. This leads to increased interfacial resistance between the electrode and electrolyte, resulting in reduced cycle life.

This technology involves mixing the NTESA additive at 1.0–5.0 wt% relative to the cathode material and heat-treating it at 400°C to modify the surface. The resulting amine/sulfone-functionalized CEI layer scavenges HF and prevents direct contact with the electrolyte, thereby suppressing electrolyte decomposition and transition metal dissolution. It can be applied to the post-processing stage for manufacturers of high-nickel cathodes like NCM811, reducing conversion costs by simply adding a mixing step to existing firing equipment.

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Key Features:

• A step of preparing a mixture by combining an NCM-based cathode active material with an N,N,N,N-tetraethylsulfamide additive for cathode material production
• A step of heat-treating the mixture of the cathode active material and the tetraethylsulfamide additive in an electric furnace at 400°C
• A Cathode-Electrolyte Interphase (CEI) layer functionalized on the cathode surface, containing amine and sulfone groups
• An N,N,N,N-tetraethylsulfamide additive contained in an amount of more than 1.0 wt% and less than 5.0 wt% relative to the weight of the cathode material

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