Unveiling the Power of Filter Paper Reinforced Polymer Composite Membrane in Zinc-Bromine Redox Flow Battery Applications

Membranes in redox flow batteries (RFBs) play a crucial role by the dual functions of separating redox-active species in the two half-cells and facilitating the passage of ions that can balance the charge neutrality. Herein, we have systematically designed a filter paper (FP) - reinforced polymer composite membrane, filter paper at Polyvinyl alcohol and bromine complexing agent (FP@PVA+BCA) and filter paper at Polyacrylonitrile (FP@PAN) in a Zinc-Bromine RFB (ZBRFB) and the performance was evaluated. FP@PVA+BCA shows an excellent performance in terms of coulombic (87.51%), voltage (81.10%), and energy (70.98%) efficiencies at 20 mA cm −2 over 100 cycles. Even at a high current density of 50 mA cm −2 , FP@PVA+BCA membrane in ZBRFB leads to 60.12% of energy efficiency which indicates the stability of the membrane during the high-power delivery. The Nafion 117 membrane energy (EE) (57.54%). Similarly, the ZBRFB assembled with FP@PAN membrane establishes significant cycling performance with coulombic (CE) (88.69%), voltage (VE) (82.23%), and energy (EE) (72.97%) efficiencies after 100 cycles at 20 mA cm −2 . Therefore, the usage of filter paper-derived membrane in RFBs hold a great attention as it possesses several features such as low cost, flexibility, and eco-friendly.