Decoration of metal organic frameworks with Fe2O3 for enhancing electrochemical performance of ZIF-(67 and 8) in energy storage application

Zeolitic imidazolate framework (ZIF) rhombic dodecahedron was homogenously decorated with Fe ₂O ₃ nanoparticles (size<100 nm) to form a two-component composite of ZIF(67-8)/Fe ₂O ₃ using a facile solvothermal approach. The performance of the obtained composites was examined as electrode materials for supercapacitors (SCs) cathode. The ZIF-8/Fe ₂O ₃composites exhibited excellent capacitive performance with a specific capacitance of 1160 F/g at the current density of 2.7 A/g. Moreover, the specific capacitance of ZIF-8/Fe ₂O ₃ was still 808 F/g at a high current density of 26.6 A/g. The strong improvement in the capacitive efficiency of the ZIF-(67-8)/Fe ₂O ₃ composites is largely due to the incorporation of Fe ₂O ₃ nanoparticles, which enhanced the composite’s electrical conductivity and facilitated the movement of electrons between the active components. Moreover, an asymmetric supercapacitor was successfully fabricated in which ZIF-8/Fe ₂O ₃ and activated carbon (AC) acted as the optimistic positive and negative electrodes, respectively. The asymmetric device achieved an energy density of 28.5 Wh/kg and a power density of 11600 W/kg, with a performance recovery of 97% after 1500 recharge-discharge cycles. This study suggests that ZIF (67-8)-based composites have promising potential in promoting of electrode materials for future supercapacitors in energy storage employment.