Non-aqueous vanadium acetylacetonate electrolyte for redox flow batteries

The electrochemistry of a single-component redox flow battery employing vanadium(III) acetylacetonate in acetonitrile and tetraethylammonium tetrafluoroborate has been investigated. The electrode kinetics of the anodic and cathodic reactions were studied using cyclic voltammetry. The V(II)/V(III) and V(III)/V(IV) couples were quasi-reversible and together yielded a cell potential of 2.2 V. The diffusion coefficient for vanadium acetylacetonate was estimated to be in the range of 1.8–2.9 × 10−6 cm2 s−1 at room temperature. The charge–discharge characteristics of this system were evaluated in an H-type glass cell, and coulombic efficiencies near 50% were achieved.