Researchers have created a high-functioning yet cheap ultracapacitor that is made from two one-atom-thick materials.

The research team mixed "graphene flakes with single-walled carbon nanotubes" to create the groundbreaking device, an American Institute of Physics news release reported.

Ultracapacitors are energy storage devices that can create surges by rapidly releasing the power. By combining the power the energy-density of batteries and the high power-density of capacitors the "ultracapacitor" can provide a boost to devices such as "electric vehicles, handheld electronics, audio systems and more," the news release reported.

Carbon nanotubes and graphene complement each other well, and both have attractive "electronic, thermal, and mechanical properties." These materials have both been considered for use in ultracapacitors in the past, but this is the first time researchers have considered combining the two.

"In our lab we developed an approach by which we can obtain both single-walled carbon nanotubes and graphene, so we came up with the idea to take advantage of the two promising carbon nanomaterials together," Michael Keidar, a professor in the Department of Mechanical and Aerospace Engineering in the School of Engineering and Applied Science at GW, and director of the Micro-propulsion and Nanotechnology Laboratory, said in the news release.

The team synthesized both the graphene flakes and nanotubes by "vaporizing a hollow graphite rod filled with metallic catalyst powder with an electric arc," the news release reported. These two structures were then mixed together to form an "ink" which they rolled onto paper.

The new device's capacitance (the measurement of its performance per unit of weight) was about three times higher than a device that was made with only nanotubes instead of the successful duo.

The researchers believe the two substances work well because the graphene flakes provide a surface and good conductivity while the nanotubes connect the structure together, forming a "network."

Besides being extremely small and light, the efficient device is a breakthrough because it will be cheaper than modern ultracapacitors.