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

Abstract

Zeolitic imidazolate framework (ZIF) rhombic dodecahedron was homogenously decorated with Fe2O3 nanoparticles (size<100 nm) to form a two-component composite of ZIF(67-8)/Fe2O3 using a facile solvothermal approach. The performance of the obtained composites was examined as electrode materials for supercapacitors (SCs) cathode. The ZIF-8/Fe2O3composites 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/Fe2O3 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)/Fe2O3 composites is largely due to the incorporation of Fe2O3 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/Fe2O3 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.