Characterization of Organic Redox Couples for Development of an Organic Redox Flow Cell

Abstract

Effective grid-scale energy storage is essential for greater incorporation of re-newable sources into the energy supply. Redox flow cells are a promising storage technology, but have yet to achieve the capabilities necessary for large-scale use. The use of organic redox couples as the fuel and oxidant in flow cells could bring the technology closer to this objective. The abilities of benzo(c)cinnoline and anthraquinone to serve as fuels in redox flow cells were evaluated via electro-chemical and spectroscopic techniques. Benzo(c)cinnoline was found to undergo a quasi-reversible reduction, but the product of this reaction appears to be too unstable for energy storage. Anthraquinone also undergoes a quasi-reversible reduction that may be appropriate for energy storage, but is too insoluble to be a practical fuel. This work demonstrates the potential of organic redox couples to serve as fuels in flow cell systems, but further work is needed to improve solubility, reversibility, and stability.