Surfactant-assisted ZIF-8/Graphene nanoplatelets nanocomposite based electrode material for high performance supercapacitor applications

Abstract

The present work reported the fabrication of high performance asymmetric supercapacitor device of graphene nanoplatelets and surfactant-assisted zeolitic imidazolate framework-8 based nanocomposite (NC: ZIF-8-C1@GNPs) electrode with organic (OE: 0.35 M K₄(Fe(CN)₆).3H₂O) electrolyte. For this, ZIF-8-C1 and NC were synthesized utilizing a solvothermal technique with cationic (cetyltrimethylammonium bromide; C1) surfactant and solid-state method, respectively. Structural characterization techniques including X-ray diffraction, X-ray photoelectron spectroscopy, Fourier Transform Infrared Spectroscopy, and Brunauer-Emmett-Teller revealed the cubic phase (I -43 m space group), and the formation of macropores (78 nm) and mesopores (∼7 nm) of the ZIF-8-C1 and NC. Scanning electron microscopy and high-resolution transmission electron microscopy elucidated the surface and inner-nanostructure morphological impact on synthesized nanocomposite (nanotubes plus nanoplatelets), respectively. The novelty of the present work is that the as-prepared NC electrodes have received minimal attention in the existing literature, highlighting a gap in research. Electrochemical investigations in three-electrode configuration confirmed that the NC electrode demonstrated exceptional performance for sustainable energy storage solutions in wide voltage window (0.0–1.0 V) than ZIF-8-C1 in -0.2–0.5 V window, achieving a significant specific capacitance of 5105 F/g (10 A/g). Furthermore, employing NC (cathode) and activated carbon (anode) electrodes in the device yielded remarkable performance characteristics in large (0.0–2.0 V) potential window, including a specific capacitance of 947.5 & 403.0 F/g (1 mV/s & 18 A/g), an energy density of 202.1 Wh/kg (18 A/g), and a power density of 52,246.6 W/kg (110 A/g). Moreover, at 50 A/g, the device exhibited excellent coulombic efficiency (92.9 %) and cycling stability (82.4 %) over 7000 charge-discharge cycles. The practical utility was demonstrated by illuminating light emitting diodes, thus open new avenues for energy storage applications.