Researchers have found a solution to use a fluoride-based battery at room temperature. An alternative to the lithium-ion battery, still experimental but promising to be more efficient and less polluting. Valuable assets for the energy transition.

Fluoride batteries are ten times more energy dense and less polluting. It is the promise made by researchers working on fluoride batteries as an alternative to the lithium-ion batteries currently in use. On December 7, in an article of Science magazine, a team from Honda’s Research Institute, California Institute of Technology (Caltech) and Nasa’s Jet Propulsion Laboratory reported that they had successfully operated such a battery at room temperature.

8 times more autonomous

The concept of fluoride batteries is not new, the researchers explain, but until now they had the enormous disadvantage of having to be heated to very high temperatures to operate: no less than 150°C. The advance presented by the scientists is, therefore, to have developed a liquid fluoride-based electrolyte that, together with a “copper-lanthanum trifluoride core and shell cathode,” operates at room temperature.

However, you will still have to wait before you can enjoy a smartphone or laptop that can last a whole week without being recharged. Many years of development are still required before such a battery can leave the laboratories.

Robert Grubbs, also co-author of the study, is, however, a little more moderate than his colleague from Honda. These batteries have the potential to last eight times longer than current batteries, “but working with fluoride is a challenge, especially because it is corrosive and reactive,” notes the researcher who was also awarded the 2005 Nobel Prize in Chemistry in a Caltech article.

Essential alternatives

Battery performance is a major industrial challenge to meet the necessary global energy transition and fight both global warming and air pollution. The intermittency of renewable energies (a wind turbine no longer produces energy when there is no wind) is a solvable problem thanks to energy storage. It can be possible through pumped energy transfer stations or batteries.

In addition to being polluting, this growing importance of lithium-ion batteries presents a risk of geopolitical tensions, as resources are highly concentrated in the hands of a few states. Alternatives are therefore developing. It is the same for the sodium battery, a very abundant supply for which a recent study by the University of Birmingham estimated that it was possible to obtain seven times more energy than the lithium-ion battery, at a constant weight.

The automotive industry is particularly interested in these solutions, with the switch to electric cars facing the constraint of battery life. With 57% growth and more than one million electric and hybrid vehicles sold in 2017, automakers like Honda are eager for cleaner and more sustainable solutions. Sodium or fluoride batteries, among other alternatives, should, therefore, continue to be developed.