Graphene helps Cambridge scientists get a step closer to the "ultimate" battery

Scientists at the University of Cambridge have created a graphene-based lithium-oxygen battery that is extremely energy dense, can be recharged more than 2000 times, and is 90% more efficient than current models. Lithium-oxygen batteries as regarded as the "ultimate" batteries because their theoretical energy density is ten times higher than a lithium-ion battery.

The researchers offered potential solutions to some of the problems facing such batteries before they can be realized, by producing a lab-based demonstrator of a lithium-oxygen battery that is a huge improvement over previous models. The new device relies on a highly porous carbon electrode made from graphene and other chemical additives. Although not all the problems have been solved, the results are a great advancement and show routes forward towards a practical device. 

Past attempts to create this type of battery have seen challenges such as low efficiency, poor rate performance, unwanted chemical reactions, and were only 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 research indeed gives hope for the future, the development of a usable form of such a battery is likely still about a decade away. The team plans to find a way to protect the metal electrode and solve further safety issues.

Source: hngn