PNNL

Abstract

Recharging battery-powered electric vehicles (EVs) in similar timeframe to that it takes for refueling gas-powered internal combustion vehicles is highly desired for large scale applications of EVs. It is well known that the electrolyte in a battery plays a critical role in fast-charging capability of the battery because it determines the rate of ion transport together with its derived electrode/electrolyte interphases on both cathode and anode of the battery. In this study, the effects of contents of salt, coordinating solvent and noncoordinating diluent on salt dissociation degree and electrolyte ionic conductivity are investigated, and a controlled solvation structure electrolyte is developed to improve the lithium ion mobility and conductivity in the electrolyte and to enhance the kinetics and stability of the electrode/electrolyte interphases in the battery. This electrolyte enables fast-charging capability of high energy density lithium-ion batteries (LIBs) at 4C rate (15-minute charging) and 5C rate (12-minute charging), which significantly outperforms the state-of-the-art electrolyte. The controlled solvation structure can shed light on future electrolyte design for fast-charging LIBs.