Liquid Power: Utilizing Redox Active Liquids as Active Material in Redox Flow Batteries
Rebecca Potash (Abruña) and Samanvaya Srivastava (Archer) are researching a new spin on RFBs.
Redox flow batteries (RFB) are currently gaining attention for large-scale grid load-leveling applications. Contemporary technology is based primarily on aqueous salt electrode solutions that are limited by low operating salt concentrations, limiting the energy density of the cell. Recently, small, redox-active organic molecules have drawn attention as alternatives to metal oxide based electrodes in traditional coin cells. These molecules exhibit higher voltages, higher capacities, and lower cost, but also show significant capacity fade due to unwanted transport of active material as these compounds are highly soluble in common battery solvents and can even be liquids themselves. We propose bridging the gap between these technologies by supplying liquid redox-active organics as an undiluted active material in RFB's. These compounds have effective molarities of 5-10M and are not limited by the narrow voltage window of water, leading to a possible 10x increase in energy
density over current technologies.