Competitive Coordination in Weakly Solvating Ether Electrolytes to Enable Fast‐Charging and Low‐Temperature Li‐Ion Batteries

ABSTRACT Conventional carbonate‐based electrolytes suffer from high freezing point and sluggish desolvation kinetics, which seriously restricts the rate and low temperature performance of lithium‐ion batteries (LIBs). Ether‐based electrolytes hold the merits of high ionic conductivity and low freezing point while they are easily co‐intercalated into the graphite layers. Herein, a weakly solvating ether of diethoxymethane (DEM) with finely tuned alkyl chain is introduced to replace the conventional 1,2‐dimethoxyethane (DME) solvent, which promotes the competitive Li + coordination with 1,3‐dioxolane (DOL), leading to an anion‐dominated solvation structure at a conventional low concentration of ∼1 m . This induces the formation of an inorganic‐rich interphase, inhibiting the co‐intercalation of ether solvent and enabling highly reversible Li + (de)intercalation to the graphite anode even at high rates and low temperatures. Coupled with its improved oxidation stability and reduced desolvation barrier, the resulting DEM/DOL electrolyte enables the graphite||LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cells to operate stably at a high rate of 5.0 C for over 2000 cycles and retain high capacity of 122 mAh g −1 at a low‐temperature of −20°C.