HKUST-1 Metal–Organic Frameworks-Derived CuO and Activated Candle Soot Carbon Nano-Onions for Highly Durable Asymmetric Supercapacitors: A Synergistic Contribution for Diffusion and Surface Controlled Charge Storage

Abstract

In the present work, a highly stable asymmetric supercapacitor is fabricated using HKUST-1 MOF-derived CuO as the cathode and low-cost activated candle soot carbon nanostructures as the anode. A pure phase of CuO is obtained by subsequent calcination of the HKUST-1 MOF octahedrons. Electrochemical measurements in a three-electrode system indicate a specific capacitance of 591 F/g for HKUST-1 MOF at a current density of 2 A/g with 2 M KOH. Whereas its derivative CuO exhibits a specific capacitance of 725 F/g, exceeding that of the pristine MOF by almost 20% at the same current density. The as-constructed HKUST-1-derived CuO//CSC device exhibits a high energy density of 28.45 Wh/kg at a power density of 1600 W/kg. Herein, we report a remarkably stable asymmetric supercapacitor device with 92.86% capacitance retention with ∼100% Coulombic efficiency after 5000 charge–discharge cycles. Thus, the synergistic combination of surface- and diffusion-controlled kinetics from redox-active MOF-derived metal oxides and conductive carbon nanostructures represents a futuristic approach to developing high-performance, durable supercapacitors.