Multifunctional Cyclic Phosphoramidate Solvent for Safe Lithium-Ion Batteries

Abstract

Since the use of high-energy-density batteries continues to expand in largescale applications, guaranteeing their safety is attracting increasing attention from the public sector and scientific communities. Considerable research efforts have been dedicated to identifying safer alternatives to the traditional electrolytes based on cyclic carbonate solvents, which represent the most flammable battery components. Nevertheless, developing functional electrolytes that may provide high safety and uncompromised electrochemical performance remains challenging. In this study, a multifunctional nonflammable solvent with improved storage stability, viz., 2-(N,Ndimethylamino)-1,3,2-dioxaphospholane 2-oxide (DMAP), is synthesized. The DMAPbased electrolytes enable the formation of a stable passivation film with high electrochemical and thermal stabilities and the suppression of exothermic reactions, resulting in the high reversibility of graphite anodes along with improved battery safety. Strategic optimization of the molecular structures of cyclic phosphoramidates should be a promising approach toward preparing highly safe batteries with high energy densities.