Triphenylboroxine and Triphenylborane as Anion Acceptors for Electrolyte in Fluoride Shuttle Batteries

Abstract

For liquid-based fluoride shuttle batteries, electrolyte composed of organic solvent and supporting electrolyte salt is developed. To increase the solubility of supporting electrolyte salt in organic solvent, anion acceptors (triphenylboroxine or triphenylborane) are added. The addition of anion acceptor greatly increases the solubility of supporting electrolyte salt, and discharge-charge reaction of BiF₃ electrode is confirmed in the prepared electrolytes. A supporting electrolyte salt (Cesium fluoride (CsF)) dissolves sparingly in an organic solvent (bis[2-(2-methoxyethoxy)ethyl]ether (tetraglyme: G4)); however, the solubility of the CsF in the G4 is greatly increased by addition of an anion acceptor (triphenylboroxine or triphenylborane). Using the developed electrolyte for fluoride shuttle battery, discharge and charge reactions of a metal fluoride electrode can be progressed.