How do you power a wearable device? Most of them require electricity, which must be stored so that it is available when needed. But batteries are problematic. They can be bulky, rigid, and filled with messy liquids that can cause trouble if they leak. One promising alternative is the use of super-capacitors — or “super-caps” — that can store a lot of electric, recharge quickly, and provide power as needed. One challenge with super-caps is how to produce them at an affordable cost.
A Scientist at Ulsan National Institute of Science and Technology (UNIST) in South Korea may have the answer. His team has developed super-caps using a standard desktop inkjet printer, fabricated on conventional paper. The process starts by depositing a conductive layer of carbon nanofibers (CNF). Electrodes are printed next, using conductive inks. Finally, a solid-state electrolyte is printed over the electrodes.
The result is a thin, lightweight, flexible, and inexpensive super-cap that can be printed in an arbitrary shape. This means that the device could be incorporated into the visual design of an object (such as arranging the electrodes to create the word “BATTERY” in the photo above). This technology could have many applications in smart garments as well as other wearable devices.