Taking a step towards stretchable electronics, scientists from the University of Texas at Austin have designed incredibly flexible battery electrodes from plain old sugar cubes. The electrodes, according to the team, are being developed for use in newly-built, bendable sodium-ion batteries. The findings of the research were recently published in the Advanced Materials journal.
Although stretchable electronics have been around for some time now, most of these devices have at least a few rigid parts. The new contraption, as pointed out by the researchers, could pave the way for fully-flexible gadgets. To create the innovative battery electrodes, the team started with the sugar cubes, using them to determine the shape, size as well as porosity required for optimal performance and efficiency.
The cubes were then carefully placed into a dish containing a special polymer gel. The next steps involved placing the Petri dish in vacuum; heating it inside an oven and finally, washing it until all the sugar got dissolved. The resultant polymeric sponge was found to be amazingly stretchable. When submerged into a highly-conductive solution containing graphene, the sponge got completely saturated, producing “sponge electrodes” in the process. Speaking about the breakthrough, Guihua Yu of UT Austin said:
This first-of-its-kind battery design maintains better mechanical properties compared with most reported designs using one or more rigid components that fail to meet the stretchability requirement for the entire device. Moreover, the demonstrated electrochemical performance rivals most previously reported stretchable energy systems. This novel stretchable sodium-ion battery represents a promising alternative for the next generation of energy-storage technologies in a broad range of applications.
As explained by the team, its porous structure lends the sponge its many incredible properties, including stretchability, high storage capacity, amazing mechanical strength as well as efficient sodium-ion transportation. At present, the battery can be elongated to around 50-percent more than its original length, without actually damaging the internal components. By altering the polymer’s properties, or even using a new elastomer, the scientists would be able to further enhance the sugar cube-derived electrodes’ flexibility.
Even after 100 cycles of being stretched to approximately 50-percent strain, the sodium-ion battery was found to reserve over 90-percent of its total capacity. The researchers are currently looking for ways to adopt the technology for larger batteries, while also trying to improve its lifespan. Once fully developed, the contraption could be used in flexible electrical displays, clean energy-harvesting devices, wearable communication gadgets, special health-monitoring sensors as well as a range of implantable medical devices. Yu added:
Future directions will be focused on further improving the mechanical properties and electrochemical performance, along with lowering the manufacturing cost.