Evaluation of an NH4VO3-derived electrolyte for the vanadium-redox flow battery

Abstract The electrolyte used in the vanadium-redox flow battery provides an energy storage system the produces no waste products. Initially, the electrolyte was derived from VOSO4 and significant cost reductions were obtained by using an electrolyte derived from V2O5. The use of NH4VO3 as the starting material for electrolyte production offers further possible cost reductions. A coulombic efficiency of 98%, a voltage efficiency of 94%, and an overall energy efficiency of 91.8% are obtained at a constant charging and discharging current density of 14.5 mA cm−2 for a test vanadium-redox flow cell that employs an electrolyte derived from NH4VO3. The electrolyte has been further treated to examine the possibility of ammonium removal. Cell-resistance measurements and cyclic voltammetry studies are reported for the treated and untreated NH4VO3 electrolyte.