Scientists have created an incredible lithium-oxygen battery that is extremely energy dense, can be recharged more then 2000 times, and is 90 percent more efficient than current models.
Lithium-oxygen batteries have been dubbed the "ultimate" batteries because their theoretical energy density is ten times higher than a lithium-ion battery, the University of Cambridge reported. This type of high-energy-density battery could be the equivalent of gasoline for electric cars, but there are still challenges that must be faced before it is realistic for the device to replace gas.
The researchers have now offered potential solutions to some of these problems by producing a lab-based demonstrator of a lithium-oxygen battery that is a vast improvement over previous models. The new device relies on a highly porous, "fluffy" carbon electrode made from graphene and other chemical additives.
"What we've achieved is a significant advance for this technology and suggests whole new areas for research - we haven't solved all the problems inherent to this chemistry, but our results do show routes forward towards a practical device," said Professor Clare Grey of Cambridge's Department of Chemistry, the paper's senior author.
Past attempts to create this type of battery have seen challenges such as " low efficiency, poor rate performance, unwanted chemical reactions, and can only be cycled in pure oxygen." This new breakthrough is characterized by very different chemistry than has been seen before because it relies on lithium hydroxide (LiOH) instead of lithium peroxide (Li2O2). When water is added and lithium iodide is employed as a "mediator," the battery experienced fewer chemical reactions, making it much more stable. The addition of the highly porous form of graphene and lithium iodide also allowed the scientists to widen the voltage gap, making for a more efficient battery.
While this new model gives the researchers hope for the future, the development of a usable "ultimate" battery is likely still a decade away. The team plans to find a way to protect the metal electrode so that it doesn't generate spindly lithium metal fibers that can lead to a battery explosion.
"While there are still plenty of fundamental studies that remain to be done, to iron out some of the mechanistic details, the current results are extremely exciting - we are still very much at the development stage, but we've shown that there are solutions to some of the tough problems associated with this technology," Grey concluded.
The findings were published in a recent edition of the journal Science.
