NASA grant funding Arruda’s research on vanadium redox

Dr. Thomas Arruda, assistant professor in the Department of Chemistry, has been awarded a 2018 grant from the NASA Research Infrastructure Development Program to support work he and his undergraduate students are doing to discover what is still largely unknown about the electrochemical reactions of vanadium redox which, once understood and optimized, could lead to its use as reliable, long-term energy storage for both terrestrial and interplanetary human space travel and colonization.

As sub-recipients of the $15,000 award from NASA Rhode Island EPSCoR-RID, Arruda and his students received federal support for their proposal, “Understanding Factors That Limit the Performance of Vanadium Redox Flow Batteries.” Students trained in the use electrochemical methods and electron paramagnetic resonance (EPR) will investigate how the chemical element vanadium reacts when used in redox flow batteries (VRFBs). When completed, their results will be published in peer-reviewed journals.

“We’re not studying the efficiency of these cells; we’re not building these cells. A lot of people are doing that,” Arruda said. “What our undergraduate student researchers are doing is fundamental experiments to learn more about the basics of these electrochemical reactions, to understand how those reactions happen and under what conditions.”

Working with Arruda on the project are Sophia Tiano ’19, Daniel Donnelly ’19, Virginia Trudel ’19 and Sean Flanagan ’17. Tiano, Donnelly and Flanagan have all received stipends during past summers to conduct research related to vanadium redox, funded by prior awards through the NASA Rhode Island Space Grant Symposium.

A byproduct of the fossil fuel industry, the chemical element vanadium is of interest to NASA as a long-term energy storage solution because the element can be charged up to four different oxidation numbers. It is not the type of battery you’ll find in a phone or laptop, Arruda said, but rather in large-scale systems where two tanks of the liquid can be stored at different charges, so each electrolyte solution can be flowed into a central reactor where a highly energetic reaction takes place and energy can be harvested.

The goal of these flow batteries is to save the energy generated from various sources, including wind and solar, for the grid. NASA has been conducting redox flow battery research since the 1970s, exploring the potential of iron and chromium for the purpose. However, those materials haven’t proven reliable for the application.

“There is always this balance in chemistry between kinetics and thermodynamics,” Arruda said. “Sometimes a reaction really wants to happen and it does, but it happens really slowly because there’s a kinetic step in the way. Sometimes a reaction doesn’t want to happen at all but if you do something to initiate it, it happens.”

With vanadium, Arruda and his student researchers are focusing on sulfuric acid and its influence on the reaction rate as a supporting electrolyte. “What we’re finding in our recently published paper (Lawton et. al., Batteries, in press) is that the higher the concentration of sulfuric acid, the faster the reaction happens,” Arruda said. “It’s kind of well-known that the acid concentration significantly influences the rate of the reaction, but the question is why. We’re trying to address that.”