Researchers develop ultra-thin supercapacitors that can be printed onto paper

Using a standard inkjet printer and regular paper, South Korean scientists can now print power sources in any design imaginable.

The supercapacitor printed into the letters ‘OR’ powers a temperature sensor at the bottom of the glass and the light-emitting diodes

 Light, thin and flexible – these are essential properties of power sources for wearable electronics and smart objects. However, batteries usually consist of coiled solid structures and liquid components, which makes it difficult to develop appropriate designs.

Sang-Young Lee and his team from the Ulsan National Institute of Science and Technology (UNIST) have designed a new class of supercapacitors that are both flat and flexible. Supercapacitors typically store more energy per mass, and can discharge and charge faster than batteries, but they are often much bigger than other portable power sources. Lee’s supercapacitors, however, consist of liquid components that cure to a solid under UV light, making it possible to print them into beautiful designs with a regular inkjet printer.

The capacitor’s electrode pairs consist of black carbon nanofiber layers, activated carbon and silver nanowire inks, and a clear electrolyte printed in between each electrode pair. To show a possible application of their flexi-printed power source, Lee’s team combined it with light-emitting diodes and a temperature sensor, creating a temperature-sensing cup.