Stable Solid Electrolyte Interphase in Cylindrical Anode-Free Li-Metal NMC90 Batteries with Li₂NiO₂ Prelithiation and Fluorine-Rich Electrolytes for High Energy Density

This study advances anode-free lithium-metal batteries (AFLMBs) by integrating nickel-rich NMC90 cathodes and fluorine-rich electrolytes in large-format 18650 cylindrical cells. A key innovation is the incorporation of 10 wt % Li-rich Li₂NiO₂ as a prelithiation agent in the cathode, which mitigates initial lithium-loss and improves the Coulombic efficiency. The electrolyte includes 30% (v/v) fluoroethylene carbonate (FEC) as a cosolvent, which suppresses inactive lithium deposition and stabilizes the solid electrolyte interphase (SEI). Unlike conventional AFLMBs that require external pressure, this work uses a stainless-steel casing with a tailored jelly roll configuration to mechanically regulate lithium plating. The optimized cells deliver an energy density of 320 Wh/kg, maintain stable cycling over 140 cycles, and support 4C-rate operation. Post-mortem analysis reveals a LiF-rich SEI that extends the cycle life, while <i>operando</i> X-ray diffraction provides insights into structural evolution. This research offers a scalable strategy for high-energy AFLMBs through the synergy of prelithiation, electrolyte design, and mechanical stabilization.