Iron MOF-derived Fe2O3/NPC decorated on MIL-88A converted Fe3C implanted electrospun porous carbon nanofibers for symmetric supercapacitors

Abstract

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 Fe3C-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 Fe2O3/NPC (NPC = nanoporous carbon) without any destruction in the morphology of the nanorods. The integrated MIL-88A-derived Fe3C reduces the intrinsic resistance and synergizes with the overall performance of the resulting negative electrode (Fe2O3/NPC@Fe3C/EPCNFs). The resulting MOF-derived electrode materials have excellent performance within the -1 to 0 window potential range. The optimized electrode Fe2O3/NPC-350@Fe3C/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 (Fe2O3/NPC-350@Fe3C/EPCNFs//Fe2O3/NPC-350@Fe3C/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.