Development of NiS@f-MWCNT nanocomposite-based high-performance supercapacitor coin cell prototype device

Abstract

This study presents the design and fabrication of a high-performance supercapacitor coin cell prototype utilizing a nickel sulfide/functionalized multi-walled carbon nanotube (NiS@f-MWCNT) nanocomposite. The nanocomposite was synthesized via a one-step hydrothermal method employing CTAB as a surfactant to ensure uniform growth and effective dispersion of NiS nanoparticles on f-MWCNTs. Structural and morphological analyses confirmed the successful integration of NiS with carbon nanotubes, leading to enhanced surface area, conductivity, and electrochemical activity. Electrochemical evaluations demonstrated a specific capacitance of ~1966 F g⁻¹ at 1 A g⁻¹ for NiS@f-MWCNT, significantly higher than bare NiS (~1400 F g⁻¹). Asymmetric supercapacitor devices assembled with NiS@f-MWCNT as the positive electrode and activated carbon as the negative electrode delivered a high energy density of ~74.1 Wh kg⁻¹ and a power density of ~1405 W kg⁻¹, along with excellent cyclic stability over 10,000 charge–discharge cycles. Furthermore, four such devices were integrated to power an Arduino-based temperature sensor, capable of detecting minor fluctuations with ±1 °C accuracy. The findings highlight the promising potential of NiS@f-MWCNT nanocomposites for next-generation energy storage systems and self-powered sensing applications, bridging the gap between laboratory-scale synthesis and practical device-level implementation.