Authors: Jianing Tian, Nan Chen, Mai Feng, Lipu Sun, Binbin Yang, Fengling Zhang, Feng Wu, Renjie Chen
Published: 2025-05-27
Source: Full article
AbstractLithium‐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 (tLi+ = 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.