Determining Vanadium Concentrations Using the UV-Vis Response Method

The ability to determine the state of charge of vanadium solutions is critical to understanding reaction mechanisms and charge transport dynamics. This paper describes in detail the methods used to generate quantitative concentrations of three of the four species in an all-vanadium flow battery. The UV-Vis method was shown to provide concentration values that were more reliable than using either an electrode voltage or the integrated current with respect to time. Furthermore, a method was proposed to bring flow battery system into charge balance by independently reducing the negative electrolyte.