Complexation of F^– by Li⁺ and Mg²⁺ Ions as Inorganic Anion Acceptors in Lactone-Based Li⁺/F^– and Mg²⁺/F^– Hybrid Electrolytes for Fluoride Shuttle Batteries

The development of high-quality fluoride-ion transporting electrolytes is a crucial demand for fluoride shuttle batteries (FSBs). However, the uncontrolled chemical and electrochemical activities ions narrow available potential window, hindering high-voltage FSB cells. We present method upgrading recently developed lactone-based liquid by complexation F – with Li + Mg 2+ ions. In resultant /F hybrid electrolytes, 2 MgF were most probable soluble complexes, effective concentrations could reach ?0.15 M along excess (Mg ) Unique interactions between observed using 19 nuclear magnetic resonance spectroscopy. thus served as inorganic anion acceptors ultimate redox stabilities to expand negative window near ?3 V vs SHE. proposed complex formation was also supported conductometric titration method. demonstrated superior versatile performances electrolyte, which enabled reversible charge/discharge reactions various metal electrodes composite in wide range series. Further, electrolyte opened valid new reaction paths aluminum, making it promising electrode