New Zinc–Vanadium (Zn–V) Hybrid Redox Flow Battery: High-Voltage and Energy-Efficient Advanced Energy Storage System

Abstract

Herein for the first time, we have reported the performance and characteristics of new high-voltage zinc–vanadium (Zn–V) metal hybrid redox flow battery using a zinc bromide (ZnBr2)-based electrolyte. The Zn–V system showed an open-circuit voltage of 1.85 V, which is very close to that of zinc–bromine flow cell. The obtained results exhibited a voltaic, Coulombic, and energy efficiencies of 88, 82, and 72% at 20 mA.cm–2, respectively, in which low-cost microporous membrane was used as a separator. However, the cell tested using Nafion-117 membrane showed voltaic, Coulombic, and energy efficiencies of 84, 83, and 71%, respectively at a current density of 20 mA.cm–2. Furthermore, the Zn–V cell performance is also compared with the Zn–Br2 flow system to highlight the advancement of the new Zn–V system. The cell also showed stable performance up to 50 cycles at a current density of 20 mA.cm-2.