Ferrous Nitrate–Nickel Oxide (Fe(NO₃)₂–NiO) Nanospheres Incorporated With Carbon Black and Polyvinylidenefluoride for Supercapacitor Applications

Ferrous nitrate/nickel oxide {Fe(NO₃)₂–NiO} nanocomposite was synthesized via two-step facile hydrothermal route. The nanocomposite exhibits crystalline structure as unveiled by X-ray diffraction (XRD) pattern, while as the scanning electron microscope (SEM) images divulge spherical morphologies for both Fe(NO₃)₂ as well as NiO nanoparticles differentiating from each other in size. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques were used to investigate supercapacitive behavior of the symmetrically fabricated nanocomposite electrode configuration using aqueous KOH as the electrolyte. The CV analyses demonstrate dominant electrical double layer capacitance (EDLC) behavior in the potential range of 0–1 V. From charge–discharge curves, the maximum specific capacitance calculated was 460 F g⁻¹ corresponding to the energy density of 16 W h kg⁻¹ at a high power density of 250 W kg⁻¹. EIS data affiliate well with the CV and GCD results justifying the maximum contribution of specific capacitance due to double layer capacitance. The nanocomposite retained 84% of its original capacitance after 1000 cycles and yielded maximum efficiency of 78%.