Engineers design tiny batteries for powering cell-sized robots

The brand new battery, which is 0.1 millimeters lengthy and 0.002 millimeters thick — roughly the thickness of a human hair — can seize oxygen from air and use it to oxidize zinc, making a present of as much as 1 volt. That is sufficient to energy a small circuit, sensor, or actuator, the researchers confirmed.

“We expect that is going to be very enabling for robotics,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior writer of the examine. “We’re constructing robotic capabilities onto the battery and beginning to put these parts collectively into gadgets.”

Ge Zhang PhD ’22 and Sungyun Yang, an MIT graduate scholar, are the lead writer of the paper, which seems in Science Robotics.

Powered by batteries

For a number of years, Strano’s lab has been engaged on tiny robots that may sense and reply to stimuli of their surroundings. One of many main challenges in growing such tiny robots is ensuring that they’ve sufficient energy.

Different researchers have proven that they will energy microscale gadgets utilizing solar energy, however the limitation to that method is that the robots will need to have a laser or one other gentle supply pointed at them always. Such gadgets are generally known as “marionettes” as a result of they’re managed by an exterior energy supply. Placing an influence supply equivalent to a battery inside these tiny gadgets may free them to roam a lot farther.

“The marionette techniques do not really want a battery as a result of they’re getting all of the power they want from exterior,” Strano says. “However in order for you a small robotic to have the ability to get into areas that you just could not entry in any other case, it must have a better stage of autonomy. A battery is important for one thing that is not going to be tethered to the surface world.”

To create robots that might turn into extra autonomous, Strano’s lab determined to make use of a sort of battery generally known as a zinc-air battery. These batteries, which have an extended lifespan than many different sorts of batteries because of their excessive power density, are sometimes utilized in listening to aids.

The battery that they designed consists of a zinc electrode linked to a platinum electrode, embedded right into a strip of a polymer known as SU-8, which is often used for microelectronics. When these electrodes work together with oxygen molecules from the air, the zinc turns into oxidized and releases electrons that circulation to the platinum electrode, making a present.

On this examine, the researchers confirmed that this battery may present sufficient power to energy an actuator — on this case, a robotic arm that may be raised and lowered. The battery may additionally energy a memristor, {an electrical} part that may retailer reminiscences of occasions by altering its electrical resistance, and a clock circuit, which permits robotic gadgets to maintain monitor of time.

The battery additionally gives sufficient energy to run two various kinds of sensors that change their electrical resistance after they encounter chemical substances within the surroundings. One of many sensors is made out of atomically skinny molybdenum disulfide and the opposite from carbon nanotubes.

“We’re making the fundamental constructing blocks with a view to construct up capabilities on the mobile stage,” Strano says.

Robotic swarms

On this examine, the researchers used a wire to attach their battery to an exterior gadget, however in future work they plan to construct robots during which the battery is included into a tool.

“That is going to type the core of a variety of our robotic efforts,” Strano says. “You may construct a robotic round an power supply, kind of like you possibly can construct an electrical automobile across the battery.”

A kind of efforts revolves round designing tiny robots that may very well be injected into the human physique, the place they may search out a goal web site after which launch a drug equivalent to insulin. To be used within the human physique, the researchers envision that the gadgets can be product of biocompatible supplies that might break aside as soon as they have been not wanted.

The researchers are additionally engaged on growing the voltage of the battery, which can allow extra purposes.

The analysis was funded by the U.S. Military Analysis Workplace, the U.S. Division of Vitality, the Nationwide Science Basis, and a MathWorks Engineering Fellowship.