Transport Properties for Ionic Liquids used in Next Generation High Capacity Batteries

Abstract

Using room temperature ionic liquids (RTILs) as electrolytes in Li-ion battery systems provides important safety and performance benefits over the more volatile, combustible organic solvents currently used. However, in order to gain a more profound understanding of transport in these electrolytes, properties such as conductivity, transference numbers, and salt activity must be measured as a function of salt concentration. Experimental methods are proposed for calculating a complete set of transport properties for a room temperature ionic liquid system. These data are also used in conjunction with concentrated solution theory equations to develop a robust porous electrode model for advanced batteries. Furthermore, the effect of organic additives on the electrolyte conductivity, internal resistances and overall cell performance was studied for a RTIL-based electrolyte system.