While some automakers are looking at solid-state batteries as the next big breakthrough for electric cars, Honda has announced that it’s testing new fluoride-ion batteries as an alternative to the current lithium-ion batteries.
Honda has teamed up with researchers at California Institute of Technology (Caltech) and NASA’s Jet Propulsion Laboratory to develop new fluoride-ion batteries, which it says have a higher energy density and better environmental footprint than current battery technologies. The team of scientists have co-authored a new paper on the topic that was published in Science, which discusses how they were able to overcome the current temperature limitations of fluoride-based battery (FIB) technology.
“Fluoride-ion batteries offer a promising new battery chemistry with up to ten times more energy density than currently available Lithium batteries,” said Dr. Christopher Brooks, Chief Scientist, Honda Research Institute, and a co-author of the paper. “Unlike Li-ion batteries, FIBs do not pose a safety risk due to overheating, and obtaining the source materials for FIBs creates considerably less environmental impact than the extraction process for lithium and cobalt.”
Honda says that thanks to the low atomic weight of fluorine, fluoride-ion batteries could offer high energy densities up to 10 times greater than lithium-ion batteries. The biggest hurdle to using the new technology is the fact that they are limited by their required temperature requirements. Currently, solid-state fluoride ion-conducting battery iterations need to operate at temperatures above 150 degrees Celsius to make the electrolyte fluoride-conducting.
To address this, the research team found a method for creating a fluoride-ion electrochemical cell capable of operating at room temperature thanks to a chemically stable liquid fluoride-conducting electrolyte with high ionic conductivity and a wide operating voltage. The scientists developed the electrolyte using dry tetraalkylammonium fluoride salts dissolved in an organic, fluorinated ether solvent. When paired with a composite cathode featuring a core-shell nanostructure of copper, lanthanum and fluorine, the researchers demonstrated reversible electrochemical cycling at room temperature.