Plasma-Induced LiF/Li ₃ N Hybrid Interphase: A Scalable Strategy for Ultrastable Lithium Metal Anodes at High Current Densities

Lithium metal anodes offer ultrahigh capacity (3860 mAh·g–1) and the lowest redox potential (−3.04 V vs S.H.E.), yet interfacial instability hinders their practical application. While Li3N and LiF are effective solid electrolyte interphase (SEI) components, conventional methods fail to construct homogeneous Li3N-rich interfaces. To overcome these limitations, we developed a nitrogen–fluorine plasma treatment approach that generates high-energy F/N-containing species, which chemically react with lithium to form an artificial LiF–Li3N composite layer.This hybrid structure synergizes LiF’s high Li+ adsorption with Li3N’s low ion-diffusion barrier (theoretically verified), enabling dendrite-free lithium deposition through uniform nucleation, enhancing the cycle life and rate performance of lithium metal. Symmetric cells with modified anodes achieve unprecedented stability over 120 h at 5 mA·cm–2/5 mAh·cm–2 in carbonate electrolytes. Full cells paired with NCM811 cathodes retain 91.33% capacity after 200 cycles at 2 C, outperforming control cells (58%). Even under more extreme 5 C conditions, the cells retained 78% capacity after 200 cycles, whereas the control group experienced catastrophic failure at the 63rd cycle. The methodology’s industrial viability is demonstrated via 83.4% capacity retention in pouch cells after 140 cycles. This work establishes plasma-assisted interface engineering as an efficient strategy for high-rate lithium metal batteries.