Lithium‐Ion Conduction Through Frozen Phase of Organic Electrolytes for Lithium Batteries

ABSTRACT Organic ice electrolytes in their frozen states are presented as molecular‐solid Li + conductors for lithium metal batteries (LMBs), challenging the notion that frozen electrolytes lack ionic conductivity. Ethylene carbonate, a cyclic carbonate, was predicted to form Li + ‐conductive channels in its frozen crystal structure. A room‐temperature ice‐phase electrolyte, EC 0.2T (0.2 m LiTFSI in ethylene carbonate), exhibited a high ionic conductivity (∼0.64 mS cm − 1 ) and a high Li + transference number (∼0.8) via hopping mechanism through solid matrix formed by immobilized solvent molecules. Frozen EC 0.2T delivered liquid‐electrolyte‐level capacity in LFP||Li cells and, more importantly, significantly extended cycle life with a solvent‐derived, Li 2 O‐rich solid electrolyte interphase.