Novel Electrolytes for Low-Temperature Electrochemical Energy Storage Devices

Abstract

There are numerous markets (Aerospace, High-Atmosphere and Automotive) requiring energy storage devices with high performance at low-temperatures. Performance of conventional devices (i.e. Li-Ion Batteries, Electrochemical Capacitors) is currently limited at low-temperatures primarily due to the electrolyte. Current Li-Ion technology necessitates the use of particular electrolyte solvents which are highly viscous and have relatively low electrolytic conductivity, preventing high performance below -20 °C. Further, Electrochemical Capacitors commonly use a highly flammable and toxic electrolyte for performance down to -40 °C and a replacement electrolyte is highly sought. Using novel solvents for Low-Temperature electrochemical energy storage devices, high performance of both Li-Ion Batteries and Electrochemical Capacitors at temperatures as low as -60 °C and -75 °C, respectively, has been demonstrated. Novel mechanisms for the superior ionic conductivity in these solvents has been studied as well as the electrochemical stability at high potentials, possibly increasing the energy density of devices. Lastly, these novel solvents are non-toxic and have low flammability, improving the safety aspects of electrochemical energy storage devices.