Redox flow batteries are a promising energy storage technology because their design allows power and energy to be decoupled. Organic electroactive active materials have attracted interest because of their tunability, which allows for molecules with high stability, high solubility, large voltage windows, and low cost to be synthesized.<br/><br/>A significant challenge in designing redox-active molecules for aqueous redox flow batteries is achieving high solubility. Charged or highly polar solubilizing groups, including carboxylates, phosphates, sulfonates, and PEG groups have been used to solubilize redox active materials. This paper reports increasing the solubility of an anthraquinone-based negative electrolyte by altering the structure of the substituents on attached to the anthraquinone ring system while simultaneously achieving a highly stable molecule in a minimal number of synthetic steps.<br/><br/>We investigated the electrochemical potential and kinetics of this electrolyte and tested its thermal stability in both the oxidized and reduced forms. We also report cell testing at high concentrations and elevated temperatures against a ferrocyanide positive electrolyte demonstrating the molecule’s ability to maintain high solubility and low capacity fade over extended cell cycling.

Highly soluble anthraquinone negative electrolyte for redox flow batteries

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.