Cofactor‐Assisted Weakly Solvated Electrolytes for Low‐Temperature Charging of Graphite Anode

Abstract Lithium‐ion batteries (LIBs) undergo significant capacity degradation at low temperatures, primarily due to the high melting point and strong Li + coordination ability of commercial ethylene carbonate (EC)‐based electrolytes. However, while ether‐based weakly solvated electrolytes (WSEs) show great promise for low‐temperature applications, their co‐intercalation into the graphite induces structure degradation, posing a significant challenge. Here, a Cofactor‐Assisted Weakly Solvated Electrolyte (CAWSE) is proposed, inspired by the cofactor‐induced modulation of surface charge distribution of enzyme molecules. To validate this mechanism, 2H,3H‐decafluoropentane (HFC) is introduced as a cofactor into a 1 m lithium bis(fluorosulfonyl)imide (LiFSI)/tetrahydrofuran (THF) electrolyte. The HFC modulates the surface charge distribution of THF through intermolecular interactions, inducing a rearrangement of solvent molecules around Li + , and significantly mitigating solvent co‐intercalation into graphite. The resulting solvation structure effectively reduces desolvation energy and stabilizes the solid electrolyte interphase, enhancing Li + transport kinetics and reducing polarization resistance at low temperatures. CAWSE exhibits high ionic conductivity (1.3 mS cm −1 at −70 °C) and a high Li + transference number (t Li + = 0.58), enabling stable Li || graphite cycling at −50 °C. At −40 °C, the cells maintain a charge capacity of 182 mAh g −1 with 82.4% retention over 100 cycles. This study presents a solvation structure rearrangement strategy, offering new insights into the development of co‐intercalation‐free electrolytes for low‐temperature graphite‐based LIBs.