Nanostructured Electrode Materials Derived from Metal–Organic Framework Xerogels for High-Energy-Density Asymmetric Supercapacitor

This work successfully demonstrates metal–organic framework (MOF) derived strategy to prepare nanoporous carbon (NPC) with or without Fe₃O₄/Fe nanoparticles by the optimization of calcination temperature as highly active electrode materials for asymmetric supercapacitors (ASC). The nanostructured Fe₃O₄/Fe/C hybrid shows high specific capacitance of 600 F/g at a current density of 1 A/g and excellent capacitance retention up to 500 F/g at 8 A/g. Furthermore, hierarchically NPC with high surface area also obtained from MOF gels displays excellent electrochemical performance of 272 F/g at 2 mV/s. Considering practical applications, aqueous ASC (aASC) was also assembled, which shows high energy density of 17.496 Wh/kg at the power density of 388.8 W/kg. The high energy density and excellent capacity retention of the developed materials show great promise for the practical utilization of these energy storage devices