NASA scientists are contemplating building a nano battery to power nanoscale devices.

In the absence of a nano battery, nanoscale devices are typically driven by power sources many times their own size.

Researchers say a key problem is how to assemble a battery on such a tiny scale, but NASA says one promising avenue is exploiting the ability of the iron-containing protein ferritin to carry either a positive or negative charge.

Ferritin self-assembles relatively easily into a uniform nanolayer. So it is straightforward to create a layer of ferritin and then cover it with another layer of the opposite charge. The result, researchers say, is a capacitor just a few nanometres thick that can store charge between its layers - in other words a battery.

Adding more layers of alternately charged ferritin increases the capacitance of this bio-nanobattery, reports New Scientist.

NASA reckons its battery is not only stable and robust, but can be produced easily and quickly too.