In-situ solvothermal synthesis of free-binder NiCo2S4/nickel foam electrode for supercapacitor application: Effects of CTAB surfactant

The free-binder NiCo₂S₄/nickel foam electrode was prepared using a two-step solvothermal method: double-layered hydroxide formation and sulfurization. The effects of cetyltrimethylammonium bromide (CTAB) on the structural, microstructural, and electrochemical properties throughout the sulfurization process were investigated using various characterization techniques. By adding the CTAB surfactant, the sheetlike morphology of NiCo₂S₄ material was transformed to a fine particular morphology. Using one mmol CTAB surfactant, the specific capacitance of NiCo₂S₄/nickel foam increased from 578 to 835 C g⁻¹ due to the downsizing of particles, inducing the higher electroactive sites for redox reactions. An asymmetric capacitor of NiCo₂S₄ as positive and CuCo₂S₄ as negative electrodes demonstrated an energy density of 23.2 Wh kg⁻¹ at a power density of 5040 W kg⁻¹.