“Dragging effect” induced fast desolvation kinetics and −50 ℃ workable high-safe lithium batteries

Propylene carbonate (PC) was once considered as the most suitable alternative to ethylene carbonate (EC) due to its high ionic conductivity and low melting point (−49 °C), whereas it shows a poor electrochemical compatibility with graphite anodes. Although designing an anion-induced ion-solvent-coordinated (AI-ISC) structure could effectively restrain the decomposition of PC on anodes, the strong interaction of Li+-PC leads to sluggish Li+ desolvation process as well as unsatisfactory low temperature performance. Here, we discovered and disclosed the mechanism of the "dragging effect" between Li+-solvent and anion-solvent, and exquisitely design a self-adapting double-layer solvation structure where free solvents outside the primary solvation sheath could effectively weaken the interactions between Li+-PC and Li+- PF6−. The rational designed LiPF6-PC/TFEP/EMC electrolyte exhibits fast desolvation kinetics and low-temperature adaptability, therefore endowing 4Ah Gr||LiNi0.8Mn0.1Co0.1O2 and 1Ah Gr||LiFePO4 pouch cells with −50 ℃ workability, long cycle life and enhanced safety. It is believed that the regulation of "dragging effect" induced self-adapting double-layer solvation structure will eventually pave the way for developing cost-effectiveness, flame-retardant, and low-temperature workable electrolytes towards all-climate and safer lithium-ion battery applications.