Designing Electrolytes With Controlled Solvation Structure for Fast-Charging Lithium-Ion Batteries

摘要

Recharging battery-powered electric vehicles (Evs) in a similar timeframe asthose used for refueling gas-powered internal combustion vehicles is highlydesirable for rapid penetration of the EV market. It is well known that theelectrolyte in a battery plays a critical role in fast-charging capability of thebattery because it determines the rate of ion transport together with itsderived electrode/electrolyte interphases on both cathode and anode of thebattery. In this study, the effects of contents of salt, coordinating solvent, andnoncoordinating diluent on salt dissociation degree and electrolyte ionicconductivity are investigated, and a controlled solvation structure electrolyteis developed to improve the lithium ion mobility and conductivity in theelectrolyte and to enhance the kinetics and stability of theelectrode/electrolyte interphases in the battery. This electrolyte enablesfast-charging capability of high energy density lithium-ion batteries (LIBs) atup to 5 C rate (12-min charging), which significantly outperforms thestate-of-the-art electrolyte. The controlled solvation structure sheds light onthe future electrolyte design for fast-charging LIBs.