NiS//MWCNT-Based Supercapacitor for Efficient Energy Storage

The current study focuses on the synthesis of nickel sulfide (NiS) nanoparticles through hydrothermal treatment using CTAB as surfactant and characterized by XRD, SEM and BET analysis. NiS electrode material for supercapacitor is characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charging and discharging (GCD) measurements in a 6 M aqueous KOH electrolyte. The NiS nanoparticles exhibited remarkable performance, achieving a specific capacitance of 850 Fg<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> at a current density of 1 Ag<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> and maintaining a cycling stability of 67% of the initial capacitance over 10,000 cycles, with a columbic efficiency of 98%. The NiS//MWCNT coin cell device demonstrated a capacitance of 50 Fg<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup>, an energy density of 23.5 Whkg<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> and a power density of 600 Wkg<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> Additionally, in a practical application, four NiS//MWCNT coin cell devices powered an Arduino-driven touch sensor capable of accurately detecting distances and recording multiple touch signals. By integrating multiwall carbon nanotubes as the negative electrode material in asymmetric supercapacitors, this study presents a novel approach to enhancing energy density and cycle life in supercapacitors.