MIT develops 0.1 mm long battery for cell-sized robots
Micro-robots are to be powered by a tiny zinc-air battery from MIT. The battery can already power actuators and sensors.
(Image: MIT)
Engineers at the Massachusetts Institute of Technology (MIT) have developed a tiny battery that absorbs oxygen from the air and uses it to oxidize zinc, generating a voltage of one volt. The battery could be used in cell-sized, autonomous robots that transport drugs in the human body with pinpoint accuracy.
The MIT battery is only 0.1 mm long and 0.002 mm thick. This makes it about as thin as a human hair, the scientists write in the study "High energy density picoliter-scale zinc-air microbatteries for colloidal robotics", which was published in Science Robotics. The micro-battery obtains its energy from the oxidation of zinc. The battery takes the oxygen required for this from the ambient air. According to the MIT researchers, the voltage of around one volt generated in this way is sufficient to supply a small circuit, a sensor or an actuator with power.
The battery itself consists of a strip of SU-8 polymer. A zinc electrode is embedded in it, which is connected to a platinum electrode. The electrodes interact with oxygen molecules from the air. The zinc oxidizes and releases electrons, which migrate to the platinum electrode and generate a current.
Micro-battery for tiny robots
The scientists want to integrate the battery into cell-sized robots that can then move autonomously - for example in the human body. The idea is for them to bring drugs such as insulin to the right target location so that their effect can be better released there. Such tiny robots are not new. Until now, they have been controlled by external magnetic fields or have received their energy from laser light, for example. However, the possible applications of such robots are then limited.
The zinc-air battery developed by MIT could give such robots a completely different level of autonomy. This type of battery is used in hearing aids, for example, and wherever a high energy density with a long service life is required.
The researchers have already been able to prove that the current of their battery is sufficient to power actuators. For example, they built an actuator that could move a small robot arm and a memristor, a passive electrical component that can store events by changing the electrical resistance. The scientists were also able to operate a clock with the battery that allows robots to keep track of time.
Sensors can also be operated with the tiny zinc-air battery. The scientists were able to power sensors that change their resistance as soon as chemicals from the air hit them.
Further improvements planned
The MIT scientists have so far connected their battery to the devices with a cable. In future, they want to integrate the battery directly into the device itself. They also want to further increase the voltage generated for other applications. For operation in micro-robots in the human body, the researchers want to manufacture the battery and the robots themselves from biocompatible materials so that everything can dissolve and degrade in the body.
(olb)