Tuning Physical and Electrochemical Properties of Lithium Metal Batteries: Effect of Lithium Difluorophosphate at Different Concentrations in 1,2‐Dimethoxyethane

Despite the reported benefits of lithium difluorophosphate (LiDFP), studies on its physical and electrochemical properties remain limited. This work systematically investigates LiDFP and its potential for lithium metal battery (LMB) electrolytes using a combined experimental and theoretical approach. Solubility, ionic conductivity, viscosity, lithium‐ion transference number, diffusion coefficient, and contact angle are experimentally evaluated to provide a comprehensive understanding of its behavior. A key finding is the decoupling of ionic conductivity and viscosity at high concentrations. Additionally, Raman and nuclear magnetic resonance spectroscopy, along with molecular dynamics simulations, reveal the formation of large cation–anion aggregates at high concentrations, which facilitate lithium‐ion transport and contribute to the stabilization of the solid electrolyte interphase. The results reported herein emphasize the potential of LiDFP as an attractive component for advanced electrolyte formulations in energy storage, providing new insights into optimizing LMB performance.