Modulating Interfacial Solvation via Ion Dipole Interactions for Low‐Temperature and High‐Voltage Lithium Batteries

Extending the stability of ether solvents is pivotal for developing low‐temperature and high‐voltage lithium batteries. Herein, we elucidate the oxidation behavior of tetrahydrofuran with ternary BF4−, PF6− and difluoro (oxalato) borate anions and the evolution of interfacial solvation environment. Combined in situ analyses and computations illustrate that the ion dipole interactions and the subsequent formation of ether‐Li+‐anion complexes in electrolyte rearrange the oxidation order of solvated species, which enhances the electrochemical stability of ether solvent. Furthermore, preferential absorption of anions on the surface of high‐voltage cathode favors the formation of a solvent‐deficient electric double layer and an anti‐oxidation cathode electrolyte interphase, inhibiting the decomposition of tetrahydrofuran. Remarkably, the formulated electrolyte based on ternary anion and tetrahydrofuran solvent endows the LiNi0.8Co0.1Mn0.1O2 cathode with considerable rate capability of 5.0 C and high capacity retention of 93.12 % after 200 cycles. At a charging voltage of 4.5 V, the Li||LiNi0.8Co0.1Mn0.1O2 cells deliver Coulombic efficiency above 99 % at both 25 and −30 °C. A non‐concentrated and fluorine‐free ether‐based electrolyte is developed to sustain lithium batteries working at high voltage and low temperature. Based on ion dipole interaction and competitive adsorption in electric double layer, the enhanced stability of electrolyte correlates with the evolution of solvation environment from bulk electrolyte to interface and the formation of antioxidant cathode electrolyte interface (CEI).