Solvent-in-salt electrolytes for fluoride ion batteries

In this paper* published in ACS Energy Letters, Professor Mauro Pasta's research group, together with the Department of Chemistry at Newcastle University, the performance of fluoride ion batteries (FIB) is examined.

FIBs contain promising chemistry due to their high theoretical energy density and the large elemental abundance of its active materials.  Nevertheless, its utilisation for room-temperature cycling has been impeded by the inability to find sufficiently stable and conductive electrolytes at room temperature.  

In this paper the authors report the use of solvent-in-salt electrolytes for FIBs, exploring multiple solvents to show that aqueous cesium fluoride exhibited sufficiently high solubility to achieve an enhanced (electro)chemical stability window (3.1 V) that could enable high operating voltage electrodes, in addition to a suppression of active material dissolution which allows for an improved cycling stability.  

The solvation structure and transport properties of the electrolyte are also investigated using spectroscopic and computational methods.

*  'Solvent-in-salt electrolytes for fluoride ion batteries'.