Enhancement of Bromine Reversibility using Chemically Modified Electrodes and their Applications in Zinc Bromine Hybrid Redox Flow Batteries

Abstract One of the significant issues that play a vital role in the determination of the performance of Zinc‐Bromine Redox Flow Battery system is the reversibility of bromine/bromide redox couple. In this work, surface modified carbon paper is used to improve the reversibility of bromine/bromide redox couple and successfully demonstrated in Zinc‐Bromine Redox Flow Battery as a positive electrode. It is evidenced that the flow cell fabricated using surface modified carbon paper showed better reaction kinetics than that of pristine carbon paper based flow cell. Further, the samples are subjected to various electrochemical and physical characterization techniques to evidence the improvement in the cell function. From the obtained cell characteristics, it is noted that the cell fabricated using surface modified carbon delivered better efficiency in terms of Coulombic (95 %), voltaic (86 %), and energy (78 %) at a current density of 20 mA/cm2. Thus, the improved effective reversibility of bromine/bromide redox couple of functionalized carbon electrode material can be a potential candidate for Zinc‐Bromine Redox Flow Battery applications.