Battery designed for "intelligent dust"

Novel energy storage brings twice the power with extremely small size

Rolled-up energy: Ultrathin coating systems are self-winding in a thousand-fold design into small energy storage devices. The combination of layers can be chosen almost arbitrarily, so that different types of energy storage are possible: capacitors release the energy quickly, batteries provide long-term storage. © TU Chemnitz
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A lot of power in the smallest of spaces: Researchers have developed a novel battery that solves previous problems in the miniaturization of these energy storage devices. The battery, which consists of alternating layers, forms almost as if by itself and quickly delivers high performance. This could predestine them for use in the tiny sensor systems of the "smart dust", as the scientists report in the journal "Nano Letters".

Without batteries no car starts, no cell phone or notebook. And pacemakers and hearing aids are also doing their job without them. Batteries and batteries provide our mobile world with the necessary energy. However, their performance is still very limited, and smaller and stronger energy stores are being sought. A commercially available battery consists of numerous, wound layers, between which the electron exchange takes place. But this is exactly where the problem lies: Because of this structure, batteries can only be scaled down to a limited extent so that the winding up of the layers only works on a macroscopic level.

Wrap layers instead

Scientists at the Chemnitz University of Technology and the Leibniz Institute for Solid State and Materials Research (IFW Dresden) have now developed a solution that overcomes this limitation in miniaturization. Instead of winding up the layers, the researchers alternately apply thin layers of metallic and dielectric materials to a flat surface. This creates a layer system that is highly braced in itself. This mechanical strain can be released by the targeted detachment of the thin layers, so that the layers roll up by themselves to an ultra-compact energy storage.

Simple technology - twice the performance

"This makes it possible to produce extremely compact energy units that can store an enormous amount of energy per unit area on a chip, more than twice as much as with conventional technologies, " explains Oliver G. Schmidt, Professor of Material Systems for Nanoelectronics at the TU Chemnitz. "And the best part is that the manufacturing process is extremely simple and works almost by itself. This is where the so-called self-organization is lovingly combined with production-ready technologies."

"We use hybrid materials for this, " reports Carlos Cesar Bof Bufon of the Chemnitz ad

Research group - different materials can be combined, such as metals and insulators, but also organic substances such as polymers or ultra-thin molecular layers. This increases the efficiency tremendously. The energy storage devices can therefore also be used in applications where high power is required quickly, such as for tiny electric motors. "The miniature batteries could also be used for the local power supply of silicon. Chips or for the drive of autonomous systems, such as small robots.

Batteries for smart Dust applications

A vision is the use in the so-called smart dust - the intelligent dust. These are tiny sensor systems that can be used, for example, for measuring temperature in cyclones. Or they go with train birds on the way to the south and follow the temperature course on the journey. "If the sensor systems are not larger than dust grains, of course, the power supply must not be large, " says Schmidt. It will take about five years to become ready for use, estimates the scientist. Ideas for further development already exist: a wire could be wrapped directly into the energy store as a coil, resulting in a miniaturized oscillating circuit.

(Technical University Chemnitz, 05.08.2010 - NPO)