The advance of renewable energy and electric vehicles (EVs) has incentivized scientists to look into various ways to solve the problem with efficient energy storage, which is the key to wider adoption of green energy technologies.
Most previous research has focused on the chemical storage and the electrochemical reactions in batteries.
Now researchers at Australia’s Queensland University of Technology (QUT) are proposing a design based on the mechanical properties of nanostructures containing diamonds that could potentially be used in mechanical energy storage devices, including batteries, biomedical sensing systems, wearables, and small robotics and electronics.
The mechanical functions of a diamond nanothread (DNT) bundle have the potential to store and release energy when stretched or twisted. These diamond nanothread bundles consist of one-dimensional carbon threads.
“Similar to a compressed coil or children’s wind-up toy, energy can be released as the twisted bundle unravels,” Dr. Haifei Zhan from the QUT Centre for Materials Science said in a statement.
Zhan and his colleagues have found that the diamond bundles have high energy density—that is how much energy a system contains compared to its mass. The team have successfully modeled the mechanical energy storage and release capabilities of a DNT bundle and published their research paper in Nature Communications.
The model is just a first step in the team’s research into the potential of mechanical energy storage as compared to electrochemical energy storage. The scientists now plan to design an experimental nanoscale mechanical energy system as proof of concept and will spend the next two-three years building the system that will control the twisting and stretching of the nanothread bundle.
Despite the fact that research into diamond nanothreads is in very early stages, initial experiments show promising results. Compared to lithium-ion batteries, the diamond nanothread bundle has up to three times the energy density, according to the QUT scientists.
“Energy dense materials are very important to many applications, which is why we are always looking for lightweight materials that still perform well,” said Dr. Zhan.
High energy density and low weight of materials used could be a major breakthrough in solving the issue of how to pack high energy potential into a lightweight energy storage system.
Because of its low weight, the diamond nanothread could find applications in aerospace electronics. Because of the mechanical—not electrochemical—nature of its energy storage potential, the diamond bundles could be used for implanted biomedical sensing systems monitoring heart and brain functions, the researchers at the QUT say. And, for batteries, the mechanical nature of the energy would be safer than the electrochemical reactions in lithium-ion batteries.
“Unlike chemical storage such as lithium-ion batteries, which use electrochemical reactions to store and release energy, a mechanical energy system itself would carry much lower risk by comparison,” Dr. Zhan said.
Mechanical energy storage systems are one of the many recent research projects and innovations in energy storage. Heat, gravity, or geothermal energy could be used to store and release energy, scientists and companies have set to prove.
While lithium-ion batteries are currently the most popular and widely used energy storage solution, the future may lie in nanostructures using mechanical rather than chemical energy forces.
According to the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy, the constantly falling costs of available renewable technologies have spurred great interest in energy storage and various solutions to improve energy storage systems.
“There’s a misunderstanding. Storage is often looked upon as electrochemical storage or battery storage,” says Adarsh Nagarajan, the group manager for Power System Design and Planning at NREL, who works on integrating renewables onto the grid.
“Storage is beyond batteries. It’s beyond electrochemical. It’s much broader.”