Low-Temperature, High Energy Density Non-Aqueous Redox Flow Battery
In our study the solubility of vanadium(III) acetylacetonate as redoxactive species and tetrabutylammonium hexafluorophosphate as supporting electrolyte were investigated in a ternary solvent mixture containing acetonitrile, 1,3-dioxolane and dimethyl sulfoxide. The solubility could be almost doubled compared to the well-known acetonitrile system . Furthermore the non-aqueous redox flow battery demonstrated good performance at -25°C (Figure 1).
Further studies to improve the solubility of redox-active species and to optimize battery tests are still under research.
Figure 1: Energy efficiency (EE) and coulombic efficiency (CE) of the V(acac)3 RFB in acetonitrile-1,3-dioxolane-dimethyl sulfoxid solvent mixture at -25°C.