Symmetric, Robust, and High-Voltage Organic Redox Flow Battery Model Based on a Helical Carbenium Ion Electrolyte

Redox flow batteries (RFBs) represent a promising technology for grid-scale integration of renewable energy. However, cross-contamination problems, encountered with distinct catholyte and anolyte, limit the development of reliable organic RFBs. Herein, we report the first use of a helical carbocation with three oxidation states, for the development of symmetric cells. Essential kinetic properties of this molecule were assessed by cyclic voltammetry. Its stability was then evaluated by mono- and bi-electronic cycling experiments, resulting in 550 and 80 cycles respectively, with high-capacity retention. This helical ion-based electrolyte achieved a proof-of-principle 2.12 V open circuit potential as an all-organic nonaqueous symmetric RFB.