Cables that store electricity

Researchers at the University of Central Florida have developed a way to both transmit and store electricity in a single lightweight copper wire.

Copper wire is the starting point but eventually as the technology improves, special fibres could also be developed with nanostructures to conduct and store energy, says nanotechnology scientist and professor Jayan Thomas, who worked on the project with his PhD student Zenan Yu.

More immediate applications could be seen in the design and development of electrical vehicles, space-launch vehicles and portable electronic devices. By being able to store and conduct energy on the same wire, heavy, space-consuming batteries could become a thing of the past. It is possible to further miniaturise the electronic devices or the space that has been previously used for batteries could be used for other purposes. In the case of launch vehicles, that could potentially lighten the load, making launches less costly, Thomas said.

Thomas and his team began with a single copper wire. Then he placed a sheath over the wire made up of nanowhiskers the team grew on the outer surface of the copper wire. These whiskers were then treated with a special alloy, which created an electrode. Two electrodes are needed for the powerful energy storage. So they had to figure out a way to create a second electrode.

They did it by adding a thin plastic sheet around the whiskers and wrapping it around using a metal sheath after generating nanowhiskers on it (the second electrode and outer covering). The layers were then glued together with a special gel. Because of the insulation, the inner copper wire retains its ability to channel energy, but the layers around the wire independently store powerful energy.

In other words, Thomas and his team created a supercapacitor on the outside of the copper wire. Supercapacitors store powerful energy, like that needed to start a vehicle or heavy-construction equipment.

Although more work needs to be done, Thomas said the technique should be transferable to other types of materials. That could lead to specially treated clothing fibres being able to hold enough power for big tasks. For example, if flexible solar cells and these fibres were used in tandem to make a jacket, it could be used independently to power electronic gadgets and other devices.

Thomas and Yu’s study is the focus of the cover story of the 30 June issue of the material science journal Advanced Materials and Nature has published a discussion about this technology in the current issue.

Yu works in Thomas’s Nano Energy-Photonics Group. It conducts research focused primarily on nanostructured supercapacitors and lithium-ion batteries, nanoarchitectured light-trapping solar cells, photorefractive polymers for 3D display applications and nonlinear optical materials.