Lauren E. VanGelder1 Anjula M. Kosswattaarachchi2 Timothy R. Cook2 Ellen Matson1

1, University of Rochester, Rochester, New York, United States
2, University at Buffalo, State University of New York, Buffalo, New York, United States

Non-aqueous redox-flow batteries have emerged as promising systems for large-capacity, reversible energy storage capable of meeting the variable demands of the electrical grid. Here, we investigate the potential for a Lindqvist polyoxovanadate-alkoxide (POV-alkoxide) clusters to serve as the electroactive species for a symmetric, non-aqueous redox-flow battery. POV-alkoxides display four quasi-reversible redox events, and demonstrate significant solubility and stability in acetonitrile across all charge-states. Using the POV-alkoxide cluster in acetonitrile as the electrolyte solution at both the anode and cathode of a static H-cell, we obtain coulombic efficiencies of nearly 100% for over 500 charge-discharge cycles. This application of hexavanadate clusters as electrolytes in organic media demonstrates that the remarkable redox properties of multi-metallic metal-oxide assemblies can be harnessed for non-aqueous energy storage applications, and represents an important new direction for the generation of high performance non-aqueous redox-flow batteries.