A tiny battery the width of a human hair could be used to power autonomous robots for drug delivery within the human body, researchers have discovered.

A team from the Massachusetts Institute of Technology (MIT) has developed the cell-sized battery, which is just 0.1mm long and 0.002mm thick.

It works by capturing oxygen from air and using it to oxidise zinc, which can create a current of up to 1 volt – enough to power a small circuit, sensor or actuator.

“We think this is going to be very enabling for robotics,” said Professor Michael Strano, senior author of the study. “We’re building robotic functions onto the battery and starting to put these components together into devices.”

While other researchers have developed microscale robots that use solar power, they must have a laser or another light source pointed at them at all times. Such devices are known as ‘marionettes’ because they are controlled by an external power source. Putting a power source such as a battery inside these tiny...