Ion-dipole regulation based on bidentate solvent for stabilizing high-voltage lithium metal batteries

Abstract

The poor compatibility of ester electrolytes with lithium metal anode severely limits its use in high voltage lithium metal batteries (LMBs). In this work, a bidentate solvent 1,2-diethoxyethane (DEE) is introduced into ester electrolyte to regulate the ion-dipole interactions to enhance the solubility of LiNO3, which enables compatibility with Li anode and maintains the high voltage cathode stability. In the designed electrolyte, the steric effect of DEE facilitates the participation of NO3– and PF6− anions in the Li+ solvation structure, thus promoting the generation of inorganic-rich solid electrolyte interphase (SEI). And the low viscosity of DEE also ensures that the ester electrolyte poses good interfacial wettability. As a result, our designed electrolyte enables the high-loading Li||NCM622 and Li||NCM811 (∼3 mA h cm−2) full cells to achieve stable cycling over 200 cycles, 8 times longer than that of a conventional ester electrolyte. This work suggests that regulation of intermolecular interactions in conventional ester electrolytes is a scalable and effective approach to achieve excellent electrochemical performance of LMBs.