Fe/N Co-doped micro-mesoporous carbon nanofibers as high-performance catalysts for zinc-bromine flow batteries

Zinc-bromine flow batteries (ZBFBs) are promising for sustainable energy storage due to their high energy density and cost-effectiveness. However, the sluggish kinetics of the Br 2 /Br − redox reaction at the cathode limits their performance. Here, we developed Fe/N co-doped micro-mesoporous carbon nanofibers (Fe-N-CNFs) as a high-performance cathode catalyst. Synthesized via electrospinning Fe/Zn-ZIFs with PAN/PVP, followed by carbonization, the Fe-N-CNFs exhibited a hierarchical pore structure with a specific surface area of 1057 ​m 2 ​g −1 and an average pore size of 2.5 ​nm. The optimized catalyst, doped with 4 ​wt% Fe, achieved an energy efficiency of 81 ​% at 80 ​mA ​cm −2 and maintained a Coulombic efficiency of 98.4 ​% over 200 cycles. This work demonstrates the potential of integrating electrospinning with MOF-derived catalysts to enhance ZBFB performance, offering a scalable solution for high-efficiency energy storage systems.