Harvard scientists power flow batteries with vitamins

Scientists from Harvard University have discovered how to create flow batteries using organic molecules inspired by vitamin B2. According to the researchers, these high-performing organic molecules can safely store electricity from intermittent energy sources such as solar and wind power in large batteries. Flow batteries are a cheaper alternative for energy storage. However, the disadvantage is that they often make use of rare earth metals and toxic compounds.

Harvard scientists had been working on cheaper, non-toxic and non-flammable alternatives since last year. They were able to develop a high-capacity flow battery that stored energy in organic molecules called quinones and a food additive called ferrocyanide, which is the first high-performance, non-flammable, non-toxic, non-corrosive and low-cost chemicals capable of storing large-scale electricity.

The team continued to work on improving the performance of the flow batteries by focusing on quinones, which are the energy-storing molecules in plants and animals. They found inspiration in vitamin B2 (riboflavin), which helps store energy from food in the body.

"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," Kaixiang Lin, first author of the study, said in a press release.

"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."

With a few tweaks to the original B2 molecule, the scientists discovered a new group of organic molecules that make good candidates for alkaline flow batteries.

"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," co-researcher Michael Aziz said in a statement.

According to the study, which was published in the journal Nature, the result of the discovery was a redox flow battery that demonstrates an open-circuit voltage approaching 1.2V, with a current efficiency of 99.7 percent and a capacity retention over 99.98 percent per cycle.

The scientists will conduct further studies on quinones and the new group of molecules in pursuit of more options for inexpensive, high-performing and long-lasting flow batteries.