A spongy nanostructure of graphene oxide was synthesized to enhance the porosity and surface area. Then, CoNi₂S₄ and MoS₂ nanocomposites were fixed on the porous graphene oxide to increase the capacity and improve its performance as a substrate. Finally, they were integrated to produce the final nanocomposite. The presence of metal sulfides, as electroactive materials, promises a synergistic effect for use in supercapacitors by accelerating ion/electron diffusion rates and enlarging the active sites. The synthesized spongy nanocomposite (CoNi₂S₄ @MoS₂ @rGO) was characterized by various techniques, including Raman spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical techniques. The results of our study showed that the spongy nanocomposite has a specific capacitance of 3268 F g⁻¹ at 1.0 A g⁻¹ in a 3.0 M KOH solution. In addition, it can sustain 93.6% stability of its initial capacity after 3000 consecutive charge-discharge cycles at a current density of 10.0 A g⁻¹. Also, the optimal potential window (from zero to 1.40 V) was determined in the asymmetric configuration of this electrode. The energy density of 41 Wh kg⁻¹ and power density of 700 W kg⁻¹ indicate the applicability of this electrode in supercapacitor application.

Keywords: Spongy nanostructure Supercapacitor Asymmetric configuration Cobalt-nickel-sulfide Molybdenum-sulfide Graphene oxide