Dual‐Salt Synergistically Induces the Formation of Organic–Inorganic Hybrid Solid Electrolyte Interphase to Suppress Lithium Dendrites

The uncontrolled growth of lithium dendrites in lithium metal anodes (LMA) remains a critical challenge for high‐energy‐density batteries, largely due to the formation of unstable solid electrolyte interphases (SEI) in conventional ester‐based electrolytes. Herein, we report a rationally designed dual‐salt electrolyte that constructs a mechanically robust and highly lithium‐ion conductive organic–inorganic hybrid SEI on LMA surfaces. The dual salts synergistically induce the formation of ionically conductive inorganic components, including LiF, Li 2 O, and Li 3 N, while simultaneously catalyzing the ring‐opening polymerization of cyclic ether solvents. This results in a SEI with enhanced flexibility and Li + transport, effectively suppressing dendritic lithium growth. Electrochemical evaluations show that the LMA with optimal dual‐salt electrolyte achieves a Coulombic efficiency (CE) of 99.15%, and Li||LiFePO 4 full cells retain 96.42% of the capacity over 200 cycles with an average CE of 99.3%. These findings highlight a synergistic interfacial engineering strategy, offering a promising pathway toward practical and safe LMA.