Modulating Interfacial Solvation via Ion Dipole Interactions for Low‐Temperature and High‐Voltage Lithium Batteries
Ping Liang, Jinhan Li, Dong Yang, Zhaodong Wang, Guoyu Ding, Kuiming Liu, Linlin Xue, Fangyi Cheng
Abstract
Abstract 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 BF 4 − , PF 6 − 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 LiNi 0.8 Co 0.1 Mn 0.1 O 2 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||LiNi 0.8 Co 0.1 Mn 0.1 O 2 cells deliver Coulombic efficiency above 99 % at both 25 and −30 °C.