Unified structural and interfacial stabilization of Ni-rich NCM811 via surface-enriched fluorination

Fluorine incorporation offers a powerful route to stabilize Ni-rich layered cathodes, yet its atomic-scale impact on structural evolution, interfacial chemistry, and electrode–electrode cross-talk has remained poorly understood. Here, we demonstrate that a controlled XeF 2 solid–gas fluorination process creates a fluorine-enriched near-surface region in LiNi 0.8 Co 0.1 Mn 0.1 O 2 , modifying both structural evolution and electrolyte interactions. Fluorination reduces c-axis contraction, moderates structural changes associated with the H2 → H3 transition, and improves Li + transport kinetics. Spectroscopic analysis reveals that the modified surface promotes preferential DMC adsorption via O···TM/Li coordination on the (104) facet, suppressing EC-driven electrolyte decomposition and suppressing CEI overgrowth. Operando FT-IR and XPS further indicate reduced cathode–anode cross-talk and mitigated phosphorus-containing species formation on the graphite anode. As a result, the optimized fluorinated cathode exhibits improved rate capability and enhanced long-term full-cell stability. These findings demonstrate the surface-enriched fluorination simultaneously regulates structural evolution and interfacial chemistry, providing a practical strategy for improving the durability of high-energy Ni-rich cathodes.