Wide‐Temperature Electrolyte Design via Cation‐Anion Solvation Engineering for 4.6 V Lithium‐Ion Batteries
Hao Zhang, Yan Zhao, Xiangrong Li, Haoliang Wang, Lu Wang, Yongli Song, Fen Qiao, Junfeng Wang, Feng Xu
Abstract
Abstract Conventional lithium‐ion batteries (LIBs) employing ethylene carbonate (EC)‐based electrolytes and thermally unstable LiPF 6 face dual challenges: sluggish Li‐ion transport at low temperatures (≤−20 °C) and severe decomposition at elevated temperatures (≥45 °C). Herein, a synergistic cation‐anion solvation engineering strategy is presented for wide‐temperature electrolytes, combining EC‐free carbonate solvents with a thermally stable ternary lithium salt system. By fine‐tuning solvent‐salt interactions, the designed electrolyte exhibits facilitated desolvation kinetics and superior ionic conductivity under subzero temperatures (0.19 mS cm −1 at −60 °C), while also maintaining excellent high‐temperature stability. The anion‐participated solvation structure induces an inorganic‐rich cathode‐electrolyte interphase (CEI), effectively stabilizing the interfacial phase of LiCoO 2 (LCO) under high voltages. Consequently, the LCO cathode with this electrolyte demonstrates robust performance under wide‐temperature operations. At 4.6 V (versus Li/Li + ), it retains 88.9% of its capacity after 400 cycles at 25 °C and 77.3% after 200 cycles at 45 °C. Remarkably, a reversible capacity of 110.1 and a discharge capacity of 92.6 mAh g −1 are delivered at −35 and −60 °C, respectively, highlighting its exceptional performance under extreme temperatures. This research pioneers a cation‐anion solvation design for tailored electrolytes, enabling reliable LIB operation across a wide temperature range.