Paper is poised to be the next key material for developing flexible energy sources for next-generation wearable devices thanks to an international team of researchers from the United States and South Korea.

Researchers from the Georgia Institute of Technology—collaborating with scientists from Korea University—have developed a flexible and inexpensive-to-fabricate paper-based supercapacitor that could be used to help power biomedical and fitness wearables, sensors to power the Internet of Things (IoT), and myriad other devices.

“Flexible energy storage devices are a key enabling factor for the propagation of wearable or paper electronics in biomedical, consumer electronics, and military applications,” said Seung Woo Lee, an assistant professor in the Woodruff School of Mechanical Engineering at Georgia Tech, who led the research. “In this work, we demonstrated high-performance, flexible energy storage devices based on the paper substrates.”

Paper and textile substrates have been considered ideal materials for energy sources for wearable tech due to their low cost, flexibility, and highly porous structures—which can absorb active electrode materials, he told Design News. However, one limitation has been that these substrates must be coated with electrically conductive materials due to their insulating nature to generate electricity.

Supercapacitors commercially are not as widely used as batteries because while they have high power density, they often have low energy density—which means they charge fast and have long lifecycles, but can’t store as much energy as batteries per unit weight. The goal of the team in their work was to boost the energy density of the supercapacitors while maintaining their high power output.