Achieving Rapid Ultralow-Temperature Ion Transfer via Constructing Lithium–Anion Nanometric Aggregates to Eliminate Li<sup>+</sup>–Dipole Interactions
Yiwei Zheng, Haoqing Ji, Tao Qian, Sijie Li, Jie Liu, Jinqiu Zhou, Zhenkang Wang, Yufei Li, Chenglin Yan
Abstract
Sluggish desolvation in extremely cold environments caused by strong Li + –dipole interactions is a key inducement for the capacity decline of a battery. Although the Li + –dipole interaction is reduced by increasing the electrolyte concentration, its high viscosity inevitably limits ion transfer at low temperatures. Herein, Li + –dipole interactions were eliminated to accelerate the migration rate of ions in electrolytes and at the electrode interface via designing Li + –anion nanometric aggregates (LA-nAGGs) in low-concentration electrolytes. Li + coordinated by TFSI – and FSI – anions instead of a donor solvent promotes the formation of an inorganic-rich interfacial layer and facilitates Li + transfer. Consequently, the LA-nAGG-type electrolyte demonstrated a high ionic conductivity (0.6 mS cm –1 ) at −70 °C and a low activation energy of charge transfer (38.24 kJ mol –1 ), enabling Li||NiFe-Prussian blue derivative cells to deliver ∼83.1% of their room-temperature capacity at −60 °C. This work provides an advanced strategy for the development of low-temperature electrolytes.