To overcome these limitations, researchers from MIT demonstrated that by adding bioengineered viruses to nanowires during the production stage -- tiny electrode wires about the width of a red blood cell -- some of these problems could be alleviated.
This virus, called M13, works by increasing the surface area of the wire, which in turn increases the area where electrochemical activity takes place when batteries are charged or discharged.
In a process similar to how an abalone pulls calcium from seawater to grow its shell, the nanowires, with the help of the M13 virus, pulls molecules of metal from room-temperature water, which the virus then binds into specific structural shapes. Specifically, the viruses produce manganese oxide wires -- and they have the rough, spiky surface required for the desired increase in surface area.
The final part of the process involves adding a small amount of metal, namely palladium, to increase the electrical conductivity of the nano wires.
Taken together, these modifications show that it may soon be possible to create a fully functional battery with an energy density that's two to three times greater than today's best lithium-air batteries -- the energy density being the amount of energy that can be stored for a given weight.