ZIF-8-Derived Nitrogen-Doped Carbon/MXene composite Modified Graphite Felt as High-Performance Anode for All Vanadium Redox Flow Batteries

Abstract Vanadium redox flow batteries (VRFBs) have been recognized as a highly promising technology for electrochemical energy storage, attributed to their excellent safety features and extended operational lifespan. However, their energy efficiency is significantly constrained by the limited electrochemical activity of the negative electrode. In this work, a nitrogen-doped porous carbon-coated MXene composite (Zn-NC/MXene) was fabricated through the in-situ growth of ZIF-8 on MXene followed by carbonization at 800 °C. This architecture features a synergistic combination of MXene’s high electrical conductivity with the abundant porosity and nitrogen-doped active sites derived from ZIF-8 derived carbon framework. Electrochemical measurements demonstrate that the Zn-NC/MXene composites significantly improve the catalytic activity and reaction kinetics of the V 3+ /V 2+ redox couple. Battery testing demonstrates that at 200mA cm −2 , the VRFB employing Zn-NC/MXene/GF as the anode achieves a 26.17% relative increase in energy efficiency (EE) and a 162.53% relative enhancement in electrolyte utilization compared to the battery using plasma-treated graphite felt (GF). The resulting approach presents a promising strategy for fabricating high-performance VRFB anodes that exhibit exceptional catalytic activity.