The world’s smallest battery has been developed by Chemnitz University of Technology researchers.
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Why the sudden demand for a smaller battery?
The trend toward miniaturisation is expanding as computers become smaller and smaller, and mobile phones offer computing power comparable to that of a laptop. To function, smart dust applications (or tiny microelectronic devices) such as biocompatible sensor systems in the body require computers and batteries that are smaller than a dust mote.
Until now, two major factors have stymied this progress: a lack of on-chip power sources that allow for operation at any time and in any location, and difficulties in manufacturing integrable microbatteries.
How can these problems be resolved?
Several scientists, including Dr. Oliver G. Schmidt, who is the head of the Professorship for Material Systems of Nanoelectronics at Chemnitz University of Technology, talk about how to solve these two problems in the most recent issue of the prestigious journal Advanced Energy Materials. They say that a solution can be found by combining these two factors.
Researchers looked at how battery-powered smart dust applications could be made in the sub-millimeter range, and they showed off the world’s smallest battery as an application-oriented prototype.
Energy storage performance at the sub-square-millimetre level is “encouraging,” says Dr Minshen Zhu, one of those who took part in the study.
Dr. Schmidt said there is still a lot of room to improve this technology, and we can expect stronger microbatteries in the future.
Scientists looked at how to make their own
Power to run tiny computers that are less than a millimetre wide can be provided by making the right batteries or using “harvesting” methods to get electricity.
This is called “harvesting.” Micro-thermoelectric generators turn heat into electricity, but their output power is too low to run chips that are smaller than a speck on the ground. Small photovoltaic cells that convert light into electricity on chips could also be used to power tiny devices. Mechanical vibrations could be another source of energy.
As a result, the world’s smallest battery isn’t possible to use on demand in most places, because light and vibrations aren’t always available at the same time and in the same places. Also in the human body, small sensors and actuators need a constant source of power. Powerful, small batteries could solve this problem, but they would be hard to find.
In addition, the production of small batteries is very different from the production of standard batteries when it comes to making batteries. This is because wet chemistry is used to make small batteries that have a lot of energy. A slurry is made of electrode materials and other ingredients, like carbon materials and binders, and then spread on a metal foil.
Microbatteries that are made with standard technologies can have a lot of energy and power density, but they take up a lot of space.
Another way to make on-chip batteries is to use layers of thin films, electrode pillars, or microelectrodes that are interconnected. It’s also possible that these designs don’t have enough energy storage, and the size of these batteries can’t be reduced to less than one square millimetre at all.
How did this technology come to be?
People who worked on this project wanted to make a battery that was smaller than one square millimetre across and could be put on a chip. It had to have a minimum energy density of 100 microwatt hours per square centimetre.
In order to do this, the team made current collectors and electrode strips at the microscale. This is the same process that Tesla uses to make batteries for its electric cars on the big scale.
A process called “micro-origami” was used by the researchers. It is made by layering thin layers of polymeric, metallic, and dielectric materials on a wafer surface.
It was easy to release the mechanical tension by peeling off the thin layers, which then automatically snapped back to roll up into the shape of a “swiss roll” (micro origami). So, no outside forces were needed to make a self-wound cylinder microbattery like this one. If you want to make chips, you can use this method. It can make high-speed micro-batteries on the surface of the wafer.
Rechargeable microbatteries made by this method could keep the world’s smallest batteries running for about 10 hours. Because this battery is so small, it could be used for things like sensors and actuators in the Internet of Things, small medical implants, microrobotic systems, and ultra-flexible electronics in the future.
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Scientists develop world’s smallest battery: The size of a grain of sand. (n.d.). Retrieved February 21, 2022, from https://www.innovationnewsnetwork.com/scientists-develop-worlds-smallest-battery-size-grain-sand/18564/
Li, Y., Zhu, M., Bandari, V. K., Karnaushenko, D. D., Karnaushenko, D., Zhu, F., & Schmidt, O. G. (2022). On‐Chip Batteries for Dust‐Sized Computers. Advanced Energy Materials, 2103641. https://doi.org/10.1002/AENM.202103641