Engineers from the Massachusetts Institute of Technology (MIT) have designed a microscale zinc-air battery to power cell-sized autonomous robots. These microbots have potential applications in medicine, from drug delivery within the human body to other fields such as inspecting gas pipelines for leaks.
The battery, measuring a miniscule 0.1 millimeters long and 0.002 millimeters thick (roughly the thickness of a human hair), is capable of extracting oxygen from the air to oxidize zinc. This process generates a current of up to 1 volt, sufficient to power a small circuit, sensor, or actuator.
"We think this is going to be very enabling for robotics," expresses Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior author of the study. "We're building robotic functions onto the battery and starting to put these components together into devices."
The research team including Ge Zhang PhD '22 and Sungyun Yang, an MIT graduate student, have been working on tiny robots that can sense and respond to their environment for several years. One of their major challenges was ensuring these tiny bots have sufficient power.
Clearly the marionette systems, powered by an external power source like solar energy, pose restrictions - the robots have to constantly be under a light source. This restricts their movement. Placing a power source like a battery inside these tiny robots broadens their scope of applications by offering them considerably more freedom to explore.
"But if you want a small robot to be able to get into spaces that you couldn't access otherwise, it needs to have a greater level of autonomy. A battery is an essential component for something that's not going to be tethered to the outside world," explains Strano.
The researchers utilized a battery known as a zinc-air battery due to its high energy density. The microbattery they designed constituted a zinc electrode linked to a platinum electrode, inserted into a strip of a polymer called SU-8 that’s commonly used for microelectronics. This electrode interaction with oxygen molecules from the air oxidizes the zinc, leading to the formation of a current.
The researchers illustrated that their battery could amply power an actuator demonstrated by raising and lowering a robotic arm. Besides, the battery could also power a memristor, an electrical component that stores event memories by altering its electrical resistance, and a clock circuit to allow robotic devices to monitor time.
Future research would focus on developing robots where the battery is incorporated within the device, creating the backbone for designing tiny robots to be injected into the human body. There, they would target a specific site and then dispense a drug like insulin. The researchers have foreseen these devices being constructed out of biocompatible materials that disintegrate once their function is served.
Disclaimer: The above article was written with the assistance of AI. The original sources can be found on ScienceDaily.
