PNNL

Abstract

Lithium metal batteries face safety and low Coulombic Efficiency barriers. Superconcentrated electrolyte is stable with lithium metal but exhibits high cost and poor wettability. We report a localized superconcentrated electrolyte by diluting a superconcentrated electrolyte with an ‘inert’ diluent which does not dissolve the salt but miscible with the solvent used in the superconcentrated electrolyte. This electrolyte exhibits low cost, good wettability, and enables dendrite-free lithium cycling with high Coulombic Efficiency (99.3%) and stability (> 95% capacity retention after 300 cycles) of lithium||LiNixMnyCozO2 batteries. The concept of localized superconcentrated electrolyte can also be applied to other multi-functional electrolytes for broad applications.