Thermal Decomposition Products and Pathways of Novel Organosilicon Electrolytes for Lithium-Ion Batteries

Abstract

Conventional lithium-ion battery carbonate-based electrolytes have displayed thermal instability and decomposition, leading to performance fade and concerns about the safety of these energy storage devices. In collaboration with the University of Wisconsin, Silatronix, Inc. has developed a novel class of organosilicon solvents for battery electrolytes which have enhanced thermal stability, long cycle lifetime, and decreased electrolytic gas evolution. We have studied the thermal stability of electrolyte systems with organosilicon solvents in comparison with conventional carbonate electrolytes. We report the quantitative analysis of solution and gas phase decomposition products over the course of several weeks under conditions of high heat and artificially increased water content. Our comparative studies of carbonate and organosilicon electrolyte thermal hydrolysis include discovery of an important donor-acceptor complex, computational modeling to identify key decomposition intermediates, and the development of kinetic degradation models. These studies help us to understand what gives rise to the superior thermal stability of these electrolyte solvents.