Researchers have come up with a material that could absorb the Sun's heat and store it in chemical form; this could be used for solar energy if the Sun is not available.
This method would not be able to effectively produce electricity, but it could be used for heat, MIT Technology Review reported.
"It could change the game, since it makes the sun's energy, in the form of heat, storable and distributable," Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, who is a co-author of a paper describing the new process in the journal Nature Chemistry, said in the article.
Molecules known as photoswitches can assume two shapes; when they are exposed to sunlight they absorb energy and "jump" from one shape to the other. The photoswitches can be prompted to return to their past configuration with a sharp jolt of electricity or heat; once they relax they tend to generate heat. The switches have the ability to store energy from the Sun indefinitely and release it when prompted to do so.
In order for the researchers to achieve their desired energy density the molecules needed to be packed extremely close together; this can be a difficult task to achieve. The researchers decided to try attaching these molecules to carbon nanotubes (CNTs).
"It's incredibly hard to get these molecules packed onto a CNT in that kind of close packing," lead author Timothy Kucharski, a postdoc at MIT and Harvard said in the news release.
The team found that even though they were only able to achieve about half of the density they had hoped the material still was capable of a significant amount of heat storage.
"After additional analysis, they realized that the photoswitching molecules, called azobenzene, protrude from the sides of the CNTs like the teeth of a comb. While the individual teeth were, indeed, twice as far apart as the researchers had hoped for, they were interleaved with azobenzene molecules attached to adjacent CNTs," the report stated.
This meant the molecules were much closer together than the researchers had previously believed. This finding could allow for the creation of a variety of new heat-storing material.
"Now we're looking at whole new classes of solar thermal materials where you can enhance this interactivity," Grossman said.
