Vitamin-powered batteries store intermittent power

We all know B vitamins are good for an energy boost, but, inspired by vitamin B2, Harvard researchers have discovered a new way to store energy: they’ve found a whole new class of high-performing organic molecules that enable large batteries to store electricity from energy sources like solar and wind power that can be intermittent.

After developing a high-capacity flow battery that stores energy in organic molecules (quinones) and a food additive (ferrocyanide), the researchers turned their attention to other organic molecules, seeking even better performance. However, finding the same versatility as quinones in other organic systems has been challenging, the researchers found.

“Now, after considering about a million different quinones, we have developed a new class of battery electrolyte material that expands the possibilities of what we can do,” said Kaixiang Lin, a PhD student at Harvard and first author of the paper.

“Its simple synthesis means it should be manufacturable on a large scale at a very low cost, which is an important goal of this project.”

Flow batteries store energy in solutions in external tanks — the bigger the tanks, the more energy they store. In 2014, a Harvard research team replaced metal ions used as conventional battery electrolyte materials in acidic electrolytes with quinones, molecules that store energy in plants and animals. In 2015, they developed a quinone that could work in alkaline solutions alongside a common food additive.

In this most recent research, the team found inspiration in vitamin B2, which helps to store energy from food in the body. The key difference between B2 and quinones is that nitrogen atoms, instead of oxygen atoms, are involved in picking up and giving off electrons.

“With only a couple of tweaks to the original B2 molecule, this new group of molecules becomes a good candidate for alkaline flow batteries,” said Michael J Aziz, from the Harvard John A Paulson School of Engineering and Applied Sciences (SEAS).

“They have high stability and solubility and provide high battery voltage and storage capacity. Because vitamins are remarkably easy to make, this molecule could be manufactured on a large scale at a very low cost.”

“We designed these molecules to suit the needs of our battery, but really it was nature that hinted at this way to store energy,” said Roy Gordon, co-senior author of the paper. “Nature came up with similar molecules that are very important in storing energy in our bodies.”

The team will continue to explore quinones, as well as this new universe of molecules, in pursuit of a high-performing, long-lasting and inexpensive flow battery.

The new research is published in Nature Energy.