Enhancement of capacitance retention of ZnCo2S4@Metal organic framework composite electrodes by hydrothermal process

Abstract

Metal organic framework-derived materials are promising electrodes for electrochemical supercapacitors due to their surface area, porosity, and excellent redox behaviors. In the present study the fabrication of ZnCo₂S₄ and ZnCo₂S₄@ZIF-67 composites synthesized by solid-state grinding and hydrothermal processing for supercapacitor utilization. Studies using XRD, XPS, FTIR, BET, FE-SEM, and HR-TEM are employed to validate the morphological, surface, and structural characteristics. Highly conductive ZnCo₂S₄ nanostructured materials are intercalated with MOF surfaces to enhance electron transport. The high number of active sites involved in the rapid electrochemical phase fluctuation using 1 M KOH electrolyte may be the cause of this. ZnCo₂S₄ and ZnCo₂S₄@ZIF-67 composites are used to create the working electrode, while a 1 M KOH electrolyte is used for the supercapacitor. By employing a three-electrode design, the created composite electrodes improve cyclic retention with specific capacitances of 245 and 447.14F/g at 1 A/g, respectively. Two electrode configurations are used to build ZnCo₂S₄@ZIF-67/1M KOH/SSC, which produced results of 151.42F/g at 1 A/g, 85.2 % capacitance retention at 7 A g⁻¹ of 7000 cycles, and 18.93 Wh kg⁻¹ energy density at 642.85 W kg⁻¹ power density. Thus, the fabricated composite electrodes may find application in electrochemical symmetric supercapacitor via two electrode configuration systems.