The miniaturization of electronics would require micro batteries of corresponding sizes. German scientists have now once again shrunken down the size of batteries taking inspiration from Swiss rolls; they have managed to develop the smallest micro battery in the world that can supply power for ultra-small implantable sensors.
The micro battery developed by the Chemnitz University of Technology is different from common batteries. Take button cell batteries that contain a higher level of energy density for instance; they are primarily made with a wet chemical process, where the electrode material and additive are applied onto the foil after being made into a slurry. The particular standard process is able to effectively elevate energy and the power density of batteries, though the size of the batteries would definitely exceed 1mm².
The German research team aims to create batteries that are smaller than 1mm², and has now managed to attain their target by taking inspiration from Swiss rolls.
Swiss rolls are delicious as they are wrapped in layers of sponge cake with jam, and this provided an idea for the scientists at the Chemnitz University of Technology to replace existing materials with current collectors and electrode strips made with polymer, dielectric materials, and metals, which are placed on the surface of the tightened chips. A delamination of the layers of materials would release tension and roll up the materials.
（Source：《Advanced Energy Materials》）
The end result is a self-wound cylinder micro-battery that is similar to the size of a piece of dust at less than 1mm², and has a minimum energy density of 100µWh/mm². Research staffs believe that these batteries can be eventually integrated onto microchips, and applied on biocompatible sensors, which can be utilized to track the oxygen level of deep tissues and the recovery status after surgeries.
With that being said, the capture of electricity remains a problem. Micro batteries can convert mechanical vibrations into electricity, or capture light to charge, though these actions cannot be attained within human bodies. The research team believes that its chargeable micro battery can provide about 10 hours of power for the smallest computer chip in the world, with other possible applications also including robot systems and ultra-flexible electronics.
Oliver Schmidt, a professor at Chemnitz University of Technology, pointed out that the results have yielded uplifting mm²-grade energy storage performance. Although there is still room for improvement, Schmidt is optimistic that stronger and more improved micro batteries will appear in the future.
(Cover photo is a sketch; source: Gerhard H Wrodnigg / CC BY-SA)
