According to a new study, scientists have made considerable advancements in the ongoing attempts to create high-energy-density batteries by showing the room-temperature workings of fluoride-ion-based, or FIB, energy cells.
Compared to other kinds of potential high-energy battery electrochemistry, like those based on nickel- or lithium-ion reactions, FIBs provide an attractive option.
Since fluorine has a low atomic weight, rechargeable batteries based on this element may provide extremely high energy densities—minimum eight times higher than the hypothetical values set for lithium-ion technologies.
Conversely, rechargeable batteries are restricted by the need for solid-state electrolytes that have to function at temperatures greater than 150 °C. The authors say that these restrictions in the electrolyte have posed a considerable problem for realizing low-temperature operating FIBs. In this regard, Victoria Davis and coworkers have reported a technique for producing a fluoride-ion electrochemical cell that has the ability to function at room temperature—a major feat made possible by a liquid fluoride-conducting and chemically stable electrolyte with a broad operating voltage and high ionic conductivity.
Davis and the team used dry tetraalkylammonium fluoride salts dissolved in an organic, fluorinated ether solvent to create the electrolyte. When combined with a composite cathode containing a core-shell nanostructure of fluorine, lanthanum, and copper, the investigators were able to show reversible electrochemical cycling at room temperature.