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segunda-feira, 25 de julho de 2011

Grafeno incrível!

...Guarda a Energia Solar por períodos de tempo indefenidos, e liberta-a quando for preciso!
Ainda é só teoria computacional, mas quando se fabricar...

Modified carbon nanotubes can store solar energy indefinitely 

Storing the sun’s heat in chemical form — rather than converting it to electricity or storing the heat itself in a heavily insulated container — has significant advantages, since in principle the chemical material can be stored for long periods of time without losing any of its stored energy. The problem with that approach has been that until now the chemicals needed to perform this conversion and storage either degraded within a few cycles, or included the element ruthenium, which is rare and expensive.

Nanoletters- Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels

UPDATE - Ars Technica notes that the material has not been made yet and is computational chemistry

In terms of energy storage, the azo/CNT nanostructures outdo lithium-ion batteries. Kolpak and Grossman calculate that the azo/CNT system will have volumetric energy densities of about 690 watt-hours per liter; lithium-ion batteries range from 200 to 600 watt-hours per liter. For comparison, azobenzene alone has a volumetric energy density of only about 90 watt-hours per litter.

Kolpak and Grossman’s proposed azo/CNT system could be adapted for use with other photoactive molecules, as it appears that placing them on carbon nanotubes enhances their energy storage properties. This is perhaps the most important result from their work.

While Kolpak and Grossman have presented a promising new approach to making solar thermal fuels, there are potential drawbacks, and the fact that they haven't actually created the substance isn't even the most substantial. The energy stored in the azo/CNT system can only be released as heat. If you want to use the stored energy to power electrical devices, you would need to convert the heat to electricity. This adds a step that requires more equipment and can result in energy loss during the conversion.

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