A diamond solution for energy storage

A safer, more stable and more efficient energy storage solution than chemical-based batteries such as lithium-ion is being touted by Queensland University of Technology (QUT) researchers.

They’ve demonstrated a new form of energy storage using bundles of diamond nanothreads (DNT) – a collection of ultrathin one-dimensional carbon threads which store energy when twisted or stretched, and then release that energy as the twisted bundle unravels.

Dr Haifei Zhan, from the QUT Centre for Materials Science

, and his colleagues successfully modelled the mechanical energy storage and release capabilities of a DNT bundle.

“Similar to a compressed coil or children’s wind-up toy, energy can be released as the twisted bundle unravels,” Zhan says.

“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.”

The new carbon structure could be a potential micro-scale power supply for EVs, implanted biomedical sensing systems monitoring heart and brain functions, through to small robotics and electronics.

“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 says.

“At high temperatures chemical storage systems can explode or can become non-responsive at low temperatures. These can also leak upon failure, causing chemical pollution,” says Zhan, adding that mechanical energy storage systems don’t have such risks.

“Previous research has shown such a structure made with carbon nanotubes could lift 50,000 times its own weight.”

Zhan’s team found the nanothread bundle’s energy density is 1.76 MJ per kilogram, which was four to five orders higher than a conventional steel spring, and up to three times compared to li-ion batteries.

Carbon nanothread bundle applications as an energy source could be endless, Zhan says.

“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.

“The nanothread bundles could be used in next-generation power transmission lines, aerospace electronics, and field emission, batteries, intelligent textiles and structural composites such as building materials.

The team is now planning production of an experimental nanoscale mechanical energy system as proof of concept, and it could take two or three years to build the control mechanism for the system to story energy.