Bundle of diamond threads can store and release energy

April 21 (UPI) -- Scientists at the Queensland University of Technology in Australia have developed a new energy storage technology using tiny diamond threads.

When the so-called diamond nanothread bundle is stretched or twisted, it stores energy. When the bundle is allowed to unravel, the energy is released.

Researchers estimate the technology could be used to harvest mechanical energy and power wearable technologies and biomedical devices. They described the bundle's impressive potential this week in the journal Nature Communications.

"Similar to a compressed coil or children's wind-up toy, energy can be released as the twisted bundle unravels," QUT mechanical engineer Haifei Zhan said in a news release. "If you can make a system to control the power supplied by the nanothread bundle it would be a safer and more stable energy storage solution for many applications."

In addition to powering devices designed to monitor heart and brain functions, the bundle could be integrated into small robotics and electronics. Their adoption could eliminate some of the risks posed by other sources of power.

"Unlike chemical storage such as lithium ion batteries, which use electro-chemical reactions to store and release energy, a mechanical energy system itself would carry much lower risk by comparison," Zhan said. "At high temperatures chemical storage systems can explode or can become non-responsive at low temperatures."

Previous tests have shown that carbon nanotubes can lift up to 50,000 times their own weight. Zhan and his colleagues estimate the new bundle could be used to develop self-powered artificial muscles.

Tests showed the bundle's stored energy density is 1.76 megajoules per kilogram, four or five times that of a conventional steel spring and three times the stored energy density of a Li-ion battery.

"Energy dense materials are very important to many applications, which is why we are always looking for lightweight materials that still perform well," Zhan said. "The benefits for aerospace applications are obvious. If we can reduce the weight of a system, we can significantly reduce its fuel requirements and costs."

Zhan and his colleagues are now working on developing a complete energy storage device using the bundle technology. To start, the scientists must build a mechanism to control the twisting and stretching of the bundle's nanothreads.