VARTM-assisted high-performance solid-state structural supercapacitor device based on the synergistic effect of Ni(OH)2-Co3S4 nanocomposite for widened potential window and charge storage mechanism

Herein, we synthesized Ni(OH)2-Co3S4 nanocomposite through facile hydrothermal synthesis, where Ni(OH)2 NPs interact synergistically with Co3S4 layers. Remarkably, the interaction of Co3S4 NPs influenced the Ni-O bond interface, and synergistic impact stimulated the development of defects and ultimately improved the characteristics of the Ni(OH)2-Co3S4 NCs. The results indicate that at a current density of 2 A/g, the specific capacitance of Ni(OH)2-Co3S4 nanocomposites using a three-electrode system was twice that of Co3S4 nanoparticles and three times that of Ni(OH)2 nanoparticles, measuring 1187.05 F/g, 573.33 F/g, and 435.20 F/g, respectively. Similarly, Ni(OH)2-Co3S4 NCs electrodes retained the capacitance over 10,000 cycles with 92% stability. Further practical applicability was demonstrated by growing NCs on woven carbon fiber, and the structured supercapacitor device was fabricated using the VARTM technique, yielding a specific capacitance of 0.92 F/cm2 at 0.20 A/cm2. This device exhibited a maximum energy density of 74.30 Wh/kg at a power density of 500 W/kg and maintained excellent cycle stability for up to 100,000 cycles, retaining 48% of its initial capacitance. These outcomes emphasize the significance of interfacial nanoengineering and give essential information for building energy storage devices for the future.