The dream of achieving a battery that allows an electric car to offer the autonomy of a model with a combustion engine, without having to ballast the vehicle with tons, is getting closer. One of the latest movements comes from the Illinois Institute of Technology and the Argonne National Laboratory, dependent on the United States Department of Energy, have developed a lithium-air battery that could make that dream come true.
And it is that energy and volumetric density is very important in applications such as road transport. But key in other potentially very interesting sectors such as air. Something that the new lithium-air design developed by these teams could make it possible to begin to address it in a broader way.
The main component of this new design of Lithium-air is a solid electrolyte. which replaces the liquid electrolyte usually used in the industry. An advance whose details have been published in science magazine.
Thanks to this, batteries offer benefits that start with greater safety due to their thermal stability. Again, an important aspect in cars or vehicles that move on land, but essential to achieve its expansion in sectors such as airplanes.
Lithium-air battery, greater safety and energy density
Undoubtedly the most interesting point is that the chemistry of the batteries developed by this team will allow increase energy density up to four times compared to current lithium batteries. Something that translates directly into greater autonomy.
According to its designers: «This lithium-air battery has the highest projected energy density of any battery technology being considered for the next generation beyond lithium-ion«.
In earlier lithium-air designs, lithium in a lithium metal anode moves through a liquid electrolyte to combine with oxygen during discharge, producing lithium peroxide (Li 2 O 2 ) or superoxide (LiO 2 ) in the cathode. Lithium peroxide or superoxide decomposes back into its lithium and oxygen components during charging. This chemical sequence stores and releases energy on demand.
But in this case a solid electrolyte composed of a ceramic polymer material made of relatively inexpensive elements in the form of nanoparticles has been used. This new solid allows chemical reactions that produce lithium oxide (Li 2 O) in the discharge.
According to Rachid Amine of the Argonne Laboratory: “More stored electrons means higher energy density. The chemical reaction of lithium superoxide or peroxide only involves one or two stored electrons per oxygen molecule, while that of lithium oxide involves four electrons.”.
The equipment’s lithium-air design is the first lithium-air battery to have achieved a four-electron reaction at room temperature. It also works with oxygen supplied by air from the surrounding environment. The ability to run on air avoids the need for oxygen tanks to operate, a problem with earlier designs.
But one of the keys to this chemistry so far has been its low shelf life. But in this case the developers have found the key, which has allowed them in the first prototypes managed to exceed 1,000 repeated charge and discharge cyclesdemonstrating its stability during the process.
This has led designers to set a goal of achieving a battery with a record energy density of 1,200 Wh/kg. That’s almost four times better than current commercial lithium batteries.
Of course as always, the question here is when. At the moment there are no dates for its arrival at a commercial phase, but if we take into account the deadlines of other manufacturers, it is to be expected that the more than 10 years of work with this type of chemical will give results in the short term, with the hope that in 2025 the first packs will begin to be installed.
