SUN STORAGE BREAKTHROUGH

Solar thermal storage: MIT breakthrough on solar triggered, reversible heat storage
Rikki Stancich, 12 August 2011 (CSP Today)

"…Rather than storing solar energy as heat, [Jeff Grossman] and Alexie Kolpak at MIT have developed a method of storing energy in a chemical form, by combining a compound called azobenzene with tiny tubular structures of pure carbon (carbon nanotubes) to produce a material capable of reversibly storing solar energy…"

[Professor Jeff Grossman, Department of Materials Science and Engineering, Massachusetts Institute of Technology:] “…[The] carbon nanotube serves as a template for the azobenzene molecules, making the pack together on the surface of the nanotube…in a way they would not normally order, either in a liquid or a solid phase…[It] gives us the opportunity to control the photochemistry of the azobenzene molecule in completely new ways…[and] turn this ordinary chromophore into an appealing material for solar thermal fuels.”

(from Grossman/Kolpak - click to enlarge)

[Professor Jeff Grossman, Department of Materials Science and Engineering, Massachusetts Institute of Technology:] “…[The] resulting fuel is transportable and can be made to store the energy for long periods of time (even years). Until it is ‘activated’ the molecule will simply remain in its excited state, not releasing any of the energy…”

[Professor Jeff Grossman, Department of Materials Science and Engineering, Massachusetts Institute of Technology:] “…The density of energy storage in the fuel is about the same as the best lithium ion batteries, but of course it should be noted that this fuel is also rechargeable by sunlight. The same material both converts and stores energy, and our predictions show that it could do so for >10^4 cycles…”