Materials and devices for sustainable energy applications

Materials for energy transport
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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.

Electrical wire

Figure 1 Quantum wires for electricity transport

Materials for 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.

Hydrogen storage

Figure 2 Reversible/tunable hydrogen storage materials.

References

Xu and Yakobson
Xu and Xue, Nanotechnology; Xue and Xu, Applied Physics Letters, J. Comp. Theo. Nanosci. (2010)