Intermolecular Hydrogen Bonding Tailors Solvation Structures for Low‐Temperature and Long‐Cycling Lithium‐Ion Batteries
Xiaoqi Wu, Huipeng Zeng, Siru He, Ruilin He, Zhen Zhang, Jiachun Wu, Jiayi Zhou, Zhida Wang, Tingting Li, Hongli Xu, Jun Wang, Chao‐Yang Wang, Guangzhao Zhang, Baomin Xu, Yonghong Deng, Shang‐Sen Chi
Abstract
Abstract Lithium iron phosphate/graphite (LFP/Gr) batteries are widely recognized for their excellent safety performance; however, their practical application under low‐temperature and fast‐charging conditions remains challenging due to sluggish lithium‐ion interfacial dynamics. In this work, a nitrile‐based electrolyte containing N,N‐dimethyltrifluoroacetamide (FDMA) is reported, which modulates lithium‐ion solvation through hydrogen bonding with the nitrile solvent (IBN), thereby optimizing interfacial transport and stabilizing the solid electrolyte interphase (SEI) at low temperatures. The Ah‐level LFP/Gr batteries with this electrolyte demonstrate outstanding cycling stability, maintaining 99.9% capacity retention over 800 cycles at −20 °C. Furthermore, the electrolyte delivers a discharge capacity of 759 mAh at −40 °C, more than three times higher than that of the baseline EC/DEC electrolyte. At room temperature, the pouch cells sustain 80% capacity retention after 535 cycles at a 2C fast‐charging rate with an average coulombic efficiency of 99.9%. This electrolyte design, driven by hydrogen‐bond‐regulated solvation structure, significantly enhances low‐temperature performance and cycling stability while maintaining excellent stability at room and elevated temperatures. These findings provide valuable insights for developing next‐generation electrolytes aimed at lithium‐ion batteries operating under extreme conditions.