Scientists claim that genetically modified viruses, used in the process of nanowires production, could boost the efficiency of lithium-air batteries, bringing the field one step closer to making the ultimate lightweight battery for electric vehicles.
The function of the virus is to capture the metal molecules from water and create structural shapes with huge surface area, a.k.a. virus-built nanowires, which can be used in the battery cathode.
The study appeared in Nature Communications, and it is authored by a team from MIT and supported by the U.S. Army Research Office and the National Science Foundation. Here, they describe how increasing the surface area of the nanowire increases the area where electrochemical activity takes place, optimizing the processes of charging and discharging. In order to do that, the team produced the M13 genetically modified virus to make wires out of manganese oxide and use them in the cathode of the lithium-air battery.
The virus is very efficient in extracting the manganese oxide from water and converting it into a nanowires with a rough and spiky surface with a large surface area. The authors explain that process is similar to the formation of abalone shells, where calcium is collected from seawater and deposited in the form of a solid structure. The advantage of this over any other existing technique is that the fabrication method does not require high temperatures or any additional chemicals. In addition, the solid structure is extremely stable, which makes it highly suitable and easy to implement in electrodes. The electrical conductivity of the new nanowires is further increased by an addition of small quantity of palladium, which boosts the catalyze reaction during charging and discharging.
The research is still in its initial stages, and a lithium-air battery, which contains the nanowires and is suitable for commercial use, is yet to be built. The team already produced the cathode, however they are still to find a durable material for the electrolyte. Nevertheless, the authors are convinced that if the technology proves successful, it will lead to the manufacturing of a lightweight lithium-air battery, which has three times higher energy density than the conventional batteries available on the market.