Enhancing the electrochemical performance of nickel cobalt sulfide nanostructures via molybdenum doping for supercapacitor applications

Abstract

The electrode materials, which exhibit improved electrochemical characteristics, have broad applications in high-capacity and high-power-density storage devices like supercapacitors. This research investigates the synthesis, electrochemical performance, and characterization of novel nanostructures comprised of molybdenum-doped nickel cobalt sulfide (Mo-NiCo₂S₄ NSs) as active electrode materials. For the first time, Mo-NiCo₂S₄ nanostructures synthesized via a one-step hydrothermal method demonstrate high efficiency as supercapacitor materials, showcasing their potential for supercapacitor applications. To examine the physical and chemical characteristics of the synthesized Mo-NiCo₂S₄ nanostructures, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) analyses were employed. Furthermore, the electrochemical efficacy of novel electrode materials was investigated using three electrodes configuration, aiming for superior performance in supercapacitor applications. Moreover, the collaborative effect of Mo-NiCo₂S₄ NSs was examined via cyclic voltammogram (CV), galvanostatic charge-discharge (GCD) curves, and electrochemical impedance spectroscopy (EIS). The cotton-like modified morphology observed via SEM revealed an increase in redox-active sites, thereby enhancing the energy storage capacity of the electrode material. The optimized sample (5 % Mo-NiCo₂S₄ NSs) demonstrated a specific capacitance of 1740 F g⁻¹ at a current density of 4 A g⁻¹. Additionally, the optimized electrode displayed notable energy density (60.4 WhKg⁻¹) and power density (500 Wkg^-1). The modified cotton-like morphology of the optimized sample exhibited superior electrochemical performance compared to the NiCo₂S₄ NSs. This study suggests that Mo-NiCo₂S₄ nanostructures hold great promise as electrode materials for future supercapacitors in energy storage systems.