Diamond nanothreads could beat batteries for energy storage, theoretical study suggests
Computational and theoretical studies of diamond-like carbon nanothreads suggest that they could provide an alternative to batteries by storing energy in a strained mechanical system. The team behind the research says that nanothread devices could power electronics and help with the shift towards renewable sources of energy.
The traditional go-to device for energy storage is the electrochemical battery, which predates even the widespread use of electricity. Despite centuries of technological progress and near ubiquitous use, batteries remain prone to the same inefficiencies and hazards as any device based on chemical reactions – sluggish reactions in the cold, the danger of explosion in the heat and the risk of toxic chemical leakages.
Another way of storing energy is to strain a material that then releases energy as it returns to its unstrained state. The strain could be linear like stretching and then launching a rubber band from your finger; or twisted, like a wind-up clock or toy. Over a decade ago, theoretical work done by researchers at the Massachusetts Institute of Technology suggested that strained chords made from carbon nanotubes could achieve impressive energy-storage densities, on account of the material’s unique mechanical properties.
Outperforms carbon nanotubes
Now, a new theoretical study by a team including Haifei Zhan, Gang Zhang and Yuantong Gu at Queensland University of Technology in Australia and the Agency for Science, Technology and Research (A*STAR) in Singapore reveals there may be circumstances in which bundles of carbon nanothreads outperform carbon nanotube bundles in terms of energy storage.
“We expected a good mechanical energy storage capability [for carbon nanothreads],” says Zhang of their results. “But surprisingly we found its energy density can be up to three times the lithium-ion battery in theory.”
First described in 2015, nanothreads joined a catalogue of carbon nanomaterials that have emerged over the past four decades. Nanothreads are 1D structures with carbon atoms linked by single bonds (like those in diamond) to three other carbon atoms and a hydrogen atom. Where the hydrogen atom is missing, the carbon atom may bond to a fourth carbon atom in an adjacent thread. This bonding contrasts with the hexagonal carbon lattices found in buckyballs, carbon nanotubes and graphene. In these materials, electron orbitals from each carbon atom are shared between just three other carbon atoms.
Since 2015 studies have revealed several ways that carbon atoms can arrange themselves in a 1D carbon nanothread structure…