The ongoing miniaturizing of electronics calls for an ongoing reimagining of the devices that power them, and a new example from scientists at the Chemnitz University of Technology has taken this technology into 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.

The groundbreaking energy storage solution was created through what's known as the Swiss-Roll process, inspired by the spongey cylindrical cakes rolled up with thick layers of jam inside. But instead of turning to sugar and flour, 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 snap back, 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.