Carbon Aerogel Functionalized Carbon Felt Electrode For High-Efficiency Alkaline Zinc and Vanadium Redox Flow Batteries

Redox flow batteries (RFBs) offer scalable energy storage solutions by decoupling power and energy density. However, enhancing power density and efficiency remains challenging. In this study, carbon aerogel (CA) is introduced as a high-surface-area electrode material to improve the electrochemical activity and stability of RFBs. CA was synthesized via sol-gel polycondensation of resorcinol and formaldehyde, with KOH as a catalyst, yielding a thermally stable, highly-porous structure. Characterization through Brunauer–Emmett–Teller analysis demonstrated a surface area of 80.41 m 2 g −1 , enhancing active sites and promoting efficient ion transport. Electrochemical testing of CA-modified zinc (ZRFB) and vanadium redox flow batteries (VRFB) revealed substantial performance improvements. In ZRFB, CA-electrode cells achieved a coulombic efficiency of 93% at 40 mA cm −2 and an energy efficiency of 63%. VRFB cells demonstrated even higher efficiency, with a coulombic efficiency of 98% and energy efficiency of 91% at 100 mA cm −2 . This study highlights CA as a cost-effective, scalable electrode material that significantly boosts RFB performance, making it highly suitable for grid-scale energy storage applications.