MACROMOLECULAR DESIGNS FOR NON-AQUEOUS REDOX FLOW BATTERY SYSTEMS
Elena C. Montoto1, Gavvalapalli Nagarjuna1, Nina Sekerak1, Marissa Kneer2, Kenneth Hernandez-Burgos1, Jeffrey S. Moore1, Joaquin Rodriguez-Lopez1.
1University of Illinois at Urbana-Champaign, Urbana, IL, 2Taylor University, Upland, IN.
Redox flow batteries (RFBs) have been shown to offer efficient grid-scale energy storage applications due to their performance and easy scalability. Aqueous RFBs are currently limited by the potential window of water, thus non-aqueous counterparts that can use a wider range of redox active species offer several advantages such as higher power and energy densities. Nevertheless, currently used ion-exchange membranes (IEMs) show low ionic conductivity in organic media. By utilizing size-exclusion principles in designing redox active species, poorly performing IEMs can be substituted with inexpensive porous separators that show higher ionic conductivities. For this approach, we have studied organic redox active colloids (RACs) in the submicron range to prevent crossover through nanoporous separators. A key challenge is controlling the size of RACs without adversely affecting chemical and structural stability, solubility, and rheological properties. This work will demonstrate the progress made toward identifying an all-RAC NRFB system by electrochemical methods. Both catholyte and anolyte RAC materials will be shown along with their characterization and performance. Our goal is to show that the use of RACs and porous separators are a viable method for designing NRFB systems.