Indispensable Interphase Passivation in Solvation‐Regulated Propylene Carbonate Electrolytes for Ah‐Level Lithium‐Ion Batteries at −50–120°C

ABSTRACT Propylene carbonate (PC) is a high‐permittivity, wide‐temperature solvent, but the Li + ‐PC co‐intercalation issue in graphite (Gr) anode curtailed its application in lithium‐ion batteries. Although solvation engineering suppresses co‐intercalation, long‐term cycling is always accompanied by a robust solid electrolyte interphase (SEI) formation. Is such a SEI indispensable for graphite cycling? Here, we distinguish the roles of solvation regulation and interphase passivation by employing ethoxy(pentafluoro)cyclotriphosphazene (PFPN) to weaken Li + –PC coordination and fluoroethylene carbonate (FEC) to form a passivating SEI. It's found that solvation regulation suppresses Li + ‐PC co‐intercalation at low currents but becomes insufficient at increased currents, where greater cathodic overpotential facilitates co‐intercalation reaction at exposed graphite sites. A continuous SEI serves as an additional Li + –PC transport barrier and is indispensable for sustaining demanding cycling. Accordingly, the optimized electrolyte enables 1.0 Ah Gr||NCM83 (LiNi 0.83 Co 0.11 Mn 0.06 O 2 ) pouch cells to achieve a high initial Coulombic efficiency of 93.5% and remain stable over 2000 cycles. Notably, the cell can operate from −50°C to 120°C, demonstrating exceptional wide‐temperature performance.