Methodology for Pyrolysis-induced Thermal Runaway Analysis in Li-ion Batteries

Abstract

As the adoption of lithium-ion batteries (LIBs) grows due to the demand for highenergy density storage solutions, ensuring their safety becomes paramount. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), which have traditionally been tools in polymer thermal analysis since the 1950s, have seen increasing use in LIB thermal research in recent decades. However, applying these techniques to LIBs poses challenges due to the multifaceted composition of LIBs and its sensitivity to environmental conditions. This research aims to overcome the inherent limitations of TGA and DSC when applied to LIBs by introducing a robust, standardized experimental protocol to ensure accuracy and consistency. Employing TGA and DSC concurrently and using sealed crucibles with pinholes, we present a comprehensive thermal profile of next-generation LiFSI-based electrolytes, revealing behaviors that differ based on solvent choice. Our analysis discerned distinct thermal properties between LiFSI-carbonate and LiFSI-ether electrolytes. Specifically, carbonate-based electrolytes displayed a pronounced exothermic peak at 350°C, indicative of significant decomposition reactions. In contrast, the LiFSI-ether electrolyte exhibited an exothermic reaction at 210°C, followed by an endothermic event near 300°C. Such variances in thermal behavior emphasize the profound influence of solvent selection on the thermal profiles of electrolyte solutions. A techno-economic assesment on sodium-ion batteries is also presented.