Materials and devices for sustainable energy applications
Materials for energy transport
Quantum wires featuring ultrahigh electrical conductivity, such as metallic carbon nanotubes, have been proposed for long-distance electricity transportation. From current fabrication techniques, metallic carbon nanotubes are always mixed with semiconducting ones. It's hard to separating them to ensure a high metallic nanotube percentage. Using numetic procedures, we study the percolation limits for a rope of quantum wires. The effects of aspect ratio have shown significant effects on the percolation threshold.
Figure 1 Quantum wires for electricity transport
energy harvesting and storage
Nanostructures such as carbon nanotube, graphene, and nanoporous materials are promising materials for hydrogen storage due to their large surface-volume ratio. The key is to have a reversible mechanism, or in other words, a method to store / release the hydrogen adsorptions. Our first-principles calculation results suggest that strain engineering is one candidate. We demostrate this concept with both carbon nanotubes and graphene sheets.
Figure 2 Reversible/tunable hydrogen storage materials.
Xu and Yakobson
Xu and Xue, Nanotechnology; Xue and Xu, Applied Physics Letters, J. Comp. Theo. Nanosci. (2010)