Chemistry Student Creates Molecule Storing Sun Energy for Hundred Years

A chemistry student in Copenhagen hit on a breakthrough effectively storing the sun’s energy.

Capturing the energy of the Sun is still rather inefficient. In just one hour planet Earth is hit by so much sunshine that humankind could cover its energy needs for an entire year. We just can’t capture this free energy efficiently yet. Research of a  student at Department of Chemistry, University of Copenhagen might have hit a breakthrough on capturing the energy of the sun.

Professor Mogens Brøndsted Nielsen leading a team at the Center for Exploitation of Solar Energy was attempting to develop molecules capable of harvesting and holding substantial amounts of solar energy, storing it for significant amounts of time, and releasing it on demand.

A year of research had shown them something that was taking on the shape of an irksome law of nature. As the capacity of the molecules to hold energy seemed to improve, the capacity to store it over time dropped; and vice versa.

The group is working with molecules known as the Dihydroazulene-Vinylheptafulvene system. Put very simply this stores energy by changing shape, but every time the Brøndsted group managed to design improved molecules, the molecules lost some of their ability to hold their “energy storage” shape, says professor Brøndsted. A student named Anders Bo Skov, who has recently started studying for his Master’s degree in chemistry at University of Copenhagen changed that.

“Regardless of what we did to prevent it, the molecules would change their shape back and release the stored energy after just an hour or two. Anders’ achievement was that he managed to double the energy density in a molecule that can hold its shape for a hundred years. Our only problem now is how we get it to release the energy again. The molecule does not seem to want to change its shape back again”, grins Mogens Brøndsted.

During his Bachelor studies Anders Bo Skov had four months to improve Brøndsted’s unstable molecule for his bachelor project. And he was successful at the task. Actually too successful as the stored energy is not getting released anymore by the stable molecules.

“What Anders has achieved is an important breakthrough. Admittedly we do not have a good method to release the energy on demand and we should increase the energy density further still. But now we know which path to take in order to succeed”, says professor Mogens Brøndsted. Skov too is excited: Mostly because his molecules are sustainable on more levels than just the obvious one. Not only do they harvest sustainable solar energy. They are also completely non-toxic, he relates.

“When it comes to storing solar power our biggest competition comes from lithium ion batteries and lithium is a poisonous metal. My molecule releases neither CO2, nor any other chemical compounds while working. It is “Sunlight in-power out”. And when the molecule wears out one day it degrades to a colorant which is also found in chamomile flowers”, explains the Masters student.

The results of the research have been published in a paper titled “Towards Solar Energy Storage in the Photochromic Dihydroazulene-Vinylheptafulvene System” in the journal Chemistry – A European Journal.