High-performance pristine ZIF-67 asymmetric supercapacitor device with excellent energy and power density for energy storage application

Abstract

The current work describes a simple and safe method for creating ZIF-67 (zeolitic imidazolate framework-67) nanostructures. X-ray diffraction (XRD) patterns reveal that the material exhibits a cubic phase free from contaminating impact. The synthesized material has a notable porosity, a high specific surface area (SSA) of ∼ 1071 m2 g−1, and a clearly defined hexagonal shape with high-resolution transmission electron microscope (HRTEM) analysis. Moreover, the electrochemical analysis in the three-electrode setup shows an extraordinary specific capacitance (CS) of 472 F g−1 and exceptional cyclic performance of 91.6 % retention in a 6 M NaOH aqueous electrolyte. Furthermore, activated carbon (AC) is being used as the negative electrode and ZIF-67 as the positive electrode to design a device with a wide potential window (1.50 V). The outstanding performance of the Asymmetric supercapacitor (ASC) device is evident in its exceptional CS (358 F g−1). This, coupled with its remarkable energy (22 Wh kg−1) and power density (4164 W kg−1), highlights its suitability for demanding energy storage applications. Notably, the device demonstrates extraordinary cyclic stability, retaining over 132 % of its initial capacitance after 5000 charge-discharge cycles, solidifying its long-term reliability. Finally, LEDs (Light Emitting Diodes) of various colors are being illuminated using three series-connected devices. Hence, the recent work is illustrating the possible practical benefit of the ongoing development of supercapacitive energy storage systems.