Organic additive coating method for improving interfacial stability of lithium-ion battery cathode materials

High-nickel cathode material with an artificial CEI formed via wet coating of a sulfonate-based organic precursor

This technology improves cathode interfacial stability by wet-coating the surface of high-nickel cathode active materials with N,N-dimethylpyrrolidinium methyl sulfate, followed by heat treatment to form a sulfonate-based artificial CEI layer that suppresses electrolyte decomposition.

High-capacity high-nickel NCM cathode active materials are highly reactive, leading to rapid side reactions with the electrolyte. The resulting decomposition products increase interfacial resistance, which severely degrades cycle performance and causes swelling.

This technology involves synthesizing the amphiphilic organic precursor N,N-dimethylpyrrolidinium methyl sulfate, wet-coating it onto the cathode surface at 1–10 wt%, and heat-treating it at 550–650℃ under atmospheric pressure to immobilize the sulfonate-based artificial CEI layer. Applicable to post-processing for NCM811 powder suppliers or high-energy-density EV cell manufacturing, it achieves superior performance metrics, including 97.4% capacity retention and 99.8% average Coulombic efficiency after 50 cycles.

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Key Features:

• Preparing a ternary layered high-nickel (High-Ni) cathode active material represented by LiNixCoyMnzO2
• Adding the cathode active material to a coating solution containing N,N-dimethylpyrrolidinium methyl sulfate and stirring to wet-coat the organic precursor onto the surface
• Separating the wet-coated cathode active material and heat-treating it to immobilize the N,N-dimethylpyrrolidinium methyl sulfate layer on the surface
• Synthesizing the precursor by adding dimethyl sulfate to a mixed solution of N-methylpyrrolidine and acetonitrile to induce N-methylation

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