Fluorinated Linkers Enable High‐Voltage Pyrrolidinium‐based Dicationic Ionic Liquid Electrolytes

Abstract

AbstractNovel fluorinated, pyrrolidinium‐based dicationic ionic liquids (FDILs) as high‐performance electrolytes in energy storage devices have been prepared, displaying unprecedented electrochemical stabilities (up to 7 V); thermal stability (up to 370 °C) and ion transport (up to 1.45 mS cm−1). FDILs were designed with a fluorinated ether linker and paired with TFSI/FSI counterions. To comprehensively assess the impact of the fluorinated spacer on their electrochemical, thermal, and physico‐chemical properties, a comparison with their non‐fluorinated counterparts was conducted. With a specific focus on their application as electrolytes in next‐generation high‐voltage lithium‐ion batteries, the impact of the Li‐salt on the characteristics of dicationic ILs was systematically evaluated. The incorporation of a fluorinated linker demonstrates significantly superior properties compared to their non‐fluorinated counterparts, presenting a promising alternative towards next‐generation high‐voltage energy storage systems.