Physical Organic Approach to Persistent, Cyclable, Low-Potential Electrolytes for Flow Battery Applications

The deployment of nonaqueous redox flow batteries for grid-scale energy storage has been impeded by a lack of electrolytes that undergo redox events at as low (anolyte) or high (catholyte) potentials as possible while exhibiting the stability and cycling lifetimes necessary for a battery device. Herein, we report a new approach to electrolyte design that uses physical organic tools for the predictive targeting of electrolytes that possess this combination of properties. We apply this approach to the identification of a new pyridinium-based anolyte that undergoes 1 e – electrochemical charge–discharge cycling at low potential (−1.21 V vs Fc/Fc + ) to a 95% state-of-charge without detectable capacity loss after 200 cycles.