Enhanced electrochemical performance of fabricated asymmetric supercapacitor in redox additive electrolyte

Abstract

The present investigation reported the solvothermal synthesis of pristine Zeolitic Imidazolate Framework-8 (ZIF-8) as an electrode for the fabrication of energy conversion and storage devices (two-electrode assembly named as ECSDs) in redox-additive (0.35 M K4(Fe(CN)6).3H2O in 6 M NaOH) electrolyte (RAE). The synthesized electrode was characterized and compared utilizing Brunauer–Emmett–Teller (BET), X-Ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), and Scanning Electron Microscopy (SEM) analysis for porosity differences, specific surface area (SSA), structural, crystallinity, and hexagonal morphology. The prepared bare ZIF-8 coupled with activated carbon (ZIF-8//AC) to evaluate the specific capacity (Cs = 256 C/g at 32 A/g), energy (ED) density, and power density (PD), known as asymmetric supercapacitor (ASSC) device. In the wide (0.0–2.1 V) potential window, the device could reach a maximum PD of 30,001.5 W/kg (for the ED of 66.67 Wh/kg at 60 A/g) and a maximum ED of 142.22 Wh/kg (for the PD of 15999.75 W/kg at 32 A/g). Furthermore, at 50 A/g (ultrahigh current density), the device exhibited outstanding cyclic stability (86.5 %) and columbic efficiency (88 %) up to 6000 galvanostatic charge-discharge (GCD) cycles. Our examination indicated that the prepared ZIF-8 presented immense potential for the practical utility of ECSDs by lightning green (∼13 min) and red (∼8 min) light-emitting diodes (LEDs).