Researchers at Germany’s Chemnitz University of Technology have created microbatteries that could be used to power advanced IoT (Internet of things) applications such as smart microsensors and millimeter-scale computing devices in the future.
The fancy fitness bands and smartwatches we use today are examples of early IoT applications (a system of computers and sensors that are connected to one another via the internet). The researchers believe that in the future, we may see “smart dust,” a highly advanced version of IoT. This technology would most likely take the form of a massive network of billions of autonomous microsensors and microcomputers.
Such micro and nano-scale devices would be distributed throughout our cities, factories, and forests (just like dust and air) and would monitor the various changes occurring around us. For example, a smart dust network in the jungle would be able to predict fire incidents far in advance by continuously monitoring moisture and heat levels. The technology may also be capable of detecting the presence of new viruses in our environment and inform us about same before they spread.
According to the researchers, all of the components of the smart dust network would use the internet to connect and exchange information with one another, just like modern smart home devices. However, providing highly efficient and tiny power sources for smart dust and other micro and nano-scale devices is a significant challenge. This is where the microbatteries demonstrated by Chemnitz University researchers may be useful.
The science behind smart dust microbatteries
The microbatteries developed by researchers are similar to the Swiss roll batteries used in Tesla’s electric vehicles. Dr. Minshen Zhu told to nanowerk, one of the study’s authors and a scientist at Chemnitz University’s Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), “the most successful design in the bulky battery world is to comprise many layers of the electrode material into a limited volume.” Tesla, for example, uses so-called Swiss roll cylinder batteries in its electric vehicles.”
The microbatteries developed by researchers are similar to the Swiss roll batteries used in Tesla’s electric vehicles. According to Dr. Minshen Zhu, one of the study’s authors and a scientist at Chemnitz University’s Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), “the most successful design in the bulky battery world is to comprise many layers of the electrode material into a limited volume.” Tesla, for example, uses so-called Swiss roll cylinder batteries in its electric vehicles.”
However, due to their 1.8 cm diameter, Tesla’s cylindrical Swiss roll batteries cannot be used directly to power a smart dust system. The researchers required batteries with micrometre diameters because, unlike a car, a smart dust network is made up of micro-scale devices. Such components necessitate high-energy density power sources with a small footprint.
As a result, the researchers decided to develop their own modified on-chip Swiss role batteries. They used micro origami, a self-assembly technique that consists of a thin metal layer (which collects current) surrounded by a stack of flat actuator layers (which regulate current movement) and swellable hydrogen layers. This complex method resulted in the formation of multiple battery rolls, each smaller than a grain of rice.
Because each microbattery has a diameter of 178 m (178 x 10-6 metres), it can be easily integrated into any chip-based system that functions as a microcomputer or a tiny sensor chip.
Not an ordinary power source
The microbatteries include an electrode slurry (a mixture of conductive particles and solvent that determines battery performance) with a one-hour drying period. This is a significant accomplishment because traditional electrode slurries require around 10 hours to dry. Longer drying periods harm the micro-layered structure of the microbatteries and reduce their energy densities.
The researchers also connected the microbatteries with a 250 micrometer-long zinc wire to achieve a desirable electrode footprint in the sub-millimeter range. “Our work provides a new technology for creating on-chip microbatteries that is compatible with both on-chip processes (lithography, etching, and so on) and battery fabrication protocols (synthesis of high-performance electrode materials, making electrode slurries, and uniform coating on the current collector),” Dr. Zhu explained.
Although the technology appears to be a great energy solution for smart dust and other micro-scale devices, it is not Dr. Zhu and his team’s first Swiss roll microbattery. They previously developed microbatteries the size of a grain of salt, and they now hope to commercialise Swiss roll microbatteries for use in real-world IoT applications.
The study is published in the journal Advanced Energy Materials.