Scientists and researchers at the Chemnitz University of Technology have taken battery technology into a tiny new territory. By deploying what’s described as a Swiss-roll-inspired self-assembly process, the researchers have produced the world’s smallest battery, which they say could find use in powering small sensors in the human body, among other applications.
It was created through the Swiss-Roll process, inspired by the spongey cylindrical cakes rolled up with thick layers of jam inside. Here, the scientists layered current collectors and electrode strips made of polymeric, metallic, and dielectric materials onto a tensioned wafer surface.
Peeling off these individual layers sees the tension released and the materials snapback, rolling up around each other to take on the same architecture as a Swiss roll cake to create a “self-wound cylinder micro-battery.” This device is smaller than one square millimeter across and around the size of a grain of dust, with a minimum energy density of 100 microwatt hours per square centimeter.
This makes the battery suitable for eventual integration into tiny chips with electrical circuits which could take the shape of biocompatible sensors in the human body. These devices can be used for tracking oxygen levels in deep tissues and monitoring recovery from surgeries to keeping an eye on vital organs.
But many of these types of sensors rely on harvesting methods to generate electricity, for example turning mechanical vibrations into energy, or capturing heat for the same purpose. The scientists claim that these can power the world’s smallest computer chips for around 10 hours, as a solution to this problem. Other possible applications include robotic systems and ultra-flexible electronics.
“There is still a huge optimization potential for this technology, and we can expect much stronger micro batteries in the future,” said Professor Oliver Schmidt, who led the research.
The research was published in the journal Advanced Energy Materials.