In operando investigations of lithium-sulfur and lithium-ion battery electrolytes using ATR FT-IR spectroscopy

Abstract

An in operando spectro-electrochemical Lithium-Sulfur cell is used to show performance benefits of using a LiNO3 additive. Using attenuated total reflection infrared spectroscopy, we are able to track the evolution of lithium polysulfides in a coin cell during cycling. We see that the concentration of polysulfides in electrolyte containing LiNO3 is substantially higher, and capacity retention of the cell is improved. ATR FT-IR spectroscopy is used to monitor thermal decomposition of organic carbonate and room temperature ionic liquid electrolytes. Samples are tested in a flooded coin cell and heated up to a temperature of 175°C. The results will be used to monitor decomposition products and study limitations inherent to RTIL electrolyte.