Activated Carbon-Anchored 3D Carbon Network for Bromine Activity and its Enhanced Electrochemical Performance in Zn-Br2 Hybrid Redox Flow Battery

There has been a huge demand on the usage of biomass-derived activated carbon as an electrode and electrocatalyst for energy storage and conversion applications owing to its abundance, high surface area, good chemical stability, low cost, and eco-friendliness. Herein, we report for the first time, activated carbon (AC) derived from Phyllanthus Emblica Leaves (PEL) (Indian gooseberry) biomass as an electrocatalyst for enhancing the bromine electro-kinetics. The AC-anchored graphite felt (AC-GF) showed excellent improvement in the bromine reversibility, which reinforces the overall performance of the zinc bromine redox flow battery (ZBRFB). Specifically, the AC-GF showed significant improvement in voltage efficiency. The flow cell employing AC in the positive electrode showed high Coulombic, voltage, and energy efficiency of 99, 83 and 82 %, respectively at a current density of 30 mA cm(-2). Furthermore, the cell showed good cycle performance with 96.43 % Coulombic efficiency retention even after 100 cycles. Thus, the significant improvement in the cell performance unveils the good electrochemical/catalytic activity of the AC and therefore can be used as a potential low-cost electrocatalyst in ZBRFB.