In-situ grown Synergistic Co-based metal-organic framework/graphene oxide composite for enhanced supercapacitor performance

Abstract

The use of pristine metal-organic frameworks (MOFs) as active electrodes for energy storage is challenging in practice due to their low conductivity and electrochemical durability. To increase the energy storage performance of the pristine MOF, an in-situ graphene oxide (GO) composite of a cobalt succinate MOF (abbreviated as Co-MOF) is designed using cheap, commercially available starting materials for an energy storage electrode. Herein, we demonstrate the MOF-GO composite with GO weight percentages of 5% (Co-MOF-GO5) and 10% (Co-MOF-GO10) to elucidate the potential of these composites for high-performance supercapacitors. Among all, the Co-MOF-GO5 exhibits the highest specific capacitance of 552 F/g, with upright cycle stability of 5000 and better energy density (33 Wh/kg) and power density (2.9 kW/kg) in a three-electrode cell system compared with pristine Co-MOF and other composites. The calculated electrochemically active surface area (ECSA) and lower charge transfer resistance also support the better performance of the Co-MOF-GO5 compared to Co-MOF-GO10. To assess the practical applicability of Co-MOF-GO5 as an energy storage material, symmetric CR2032 coin-cell devices were fabricated by using the Co-MOF-GO5 at 2 both electrodes with aqueous KOH electrolyte, which can power a commercially available light-emitting diode bulb (∼1.8 V) for a few minutes.