Ni-rich NCM811 cathodes offer a high specific capacity but experience severe degradation under high-rate cycling owing to interfacial side reactions and structural instability. In this study, BaTiO₃ (BT), a high-dielectric ferroelectric, was applied as a nanodot surface coating using a room-temperature, solvent-free Resonant Acoustic Mixing (RAM) process. The RAM process enables uniform nanoparticle dispersion without requiring thermal treatment or complex post-processing, thereby providing a simple and efficient strategy for interfacial modification using dielectric coatings. NCM811 powders were coated with varying amounts of BT (1-10 wt%) and evaluated via rate capability, impedance spectroscopy, and long-term cycling. Among them, the 2 wt% composition showed the most pronounced improvement. The BT-coated electrodes exhibited consistently enhanced rate performance compared to bare NCM across all charge-discharge rates (C-rates; 0.1-10C). Notably, at 10 C, the 2 wt% BT-coated sample delivered a 14.2% higher discharge capacity, confirming superior high-rate capability. Charge transfer resistance was reduced by 51.8%, and lithium-ion diffusion improved by 107%, indicating faster reaction kinetics. Furthermore, under long-term cycling at 10 C, the coated electrode retained more than 50% of its initial capacity after 200 cycles, demonstrating improved structural and interfacial stability. These findings demonstrate that the BT nanodot coating, applied via a solvent-free and room-temperature RAM process, functions as a multifunctional interfacial layer that suppresses interfacial degradation through physical protection and enhances lithium-ion mobility by modulating local electric fields. The RAM technique enabled uniform nanodot dispersion without damaging the NCM crystal structure and offers an efficient, scalable, and post-treatment-free route for advanced lithium-ion battery cathode design.

Keywords: Lithium-ion battery, Ni-rich cathode, BaTiO₃ coating, Resonant acoustic mixing, High-rate cycling