Advances in Chelated Metal Electrolyte for Aqueous Flow Batteries

Flow battery electrolyte containing chelated metal ions can support high voltage, high power, and high efficiency battery cycling in pH-neutral conditions. In this talk the coordination behavior and flow battery performance of chelated metal ions including vanadium, chromium, iron, and cerium will be presented. Key to enabling this approach is the fundamental understanding of the coordination properties of the chelating agent to specific metal ions and oxidation states. Techno-economic analyses suggest that the performance advantages of chelation more than offsets the cost of the chelating agents. Finally, strategies towards high concentration (> 2 M) cycling of these electrolytes will be presented, and the implications of energy density on overall system footprint will be discussed.