Iron MOF-Derived Fe₂O₃/NPC Decorated on MIL-88A Converted Fe₃C Implanted Electrospun Porous Carbon Nanofibers for Symmetric Supercapacitors

Moderated thermal transformation of metal–organic frameworks (MOFs) empowers the synthesis of nanomaterials with precisely controlled porosities and morphologies, leading to enhanced performance in energy storage applications. Herein, we prepared MIL-88A-derived Fe 3 C-integrated EPCNFs (EPCNFs = electrospun porous carbon nanofibers) mats for the outside growth of Fe-MOFs using a moderated temperature calcination technique. The applied technique endorsed the conversion of the Fe-MOFs into Fe 2 O 3 /NPC (NPC = nanoporous carbon) without any destruction in the morphology of the nanorods. The integrated MIL-88A-derived Fe 3 C reduces the intrinsic resistance and synergizes with the overall performance of the resulting negative electrode (Fe 2 O 3 /NPC@Fe 3 C/EPCNFs). The resulting MOF-derived electrode materials have excellent performance within the −1 to 0 window potential range. The optimized electrode Fe 2 O 3 /NPC-350@Fe 3 C/EPCNFs exhibits a high specific capacitance (531 F g –1 at 1 A g –1 ) and stable cycling performance, retaining more than 90% even after 20000 cycles. The uniform, vertical, porous, and highly interconnected tetragonal rod-like nanomaterials can also maintain structural integrity during continuous charge/discharge. In addition, the assembled symmetric supercapacitor (Fe 2 O 3 /NPC-350@Fe 3 C/EPCNFs//Fe 2 O 3 /NPC-350@Fe 3 C/EPCNFs) exhibits an energy density of 21.6 W h kg –1 at a power density of 499.05 W kg –1 with superior cycling stability (20000 cycles at 20 A g –1 ), indicating the feasibility of the prepared electrode for practical application in energy storage systems.