Binder-free electrode based on Zn-doped Ni3S2 vertically grown 2-dimensional nanostructures on Ni foam with boosted electrochemical performance for energy storage applications

Transition metal sulfides have drawn a lot of interest in the field of electrochemical energy storage. However, their performance is hampered due to the stacking faults during the electrode fabrication. In this study, we report the Zn-doped Ni₃S₂ vertically grown 2-dimensional nanostructures on the conductive nickel foam by a one-step, rapid, energy-efficient, and cost-effective microwave-assisted method. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM) analyses confirmed the morphological and phase composition as initially identified by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical investigations substantiated the boosted performance of the electrode, an impressive specific capacitance value of 1984 F g⁻¹ and 5.95 F cm⁻² at a discharge current of 3 mA cm⁻². Later on, this electrode, when tested in a Swagelok cell as a positive electrode and graphene nano pellets as a negative electrode, achieved a maximum energy density of 45.5 Whkg⁻¹ and 910 Wkg⁻¹ power at a discharge current rate of 1 A g⁻¹. The pseudocapacitive characteristics of this binder-free nanostructured electrode, driven by reversible redox reactions, highlight their potential for high-performance energy storage applications.