Pseudocapacitance of Co doped NiO nanoparticles and its room temperature ferromagnetic behavior

Highlights: • Pseudocapacitance of Co doped NiO nanoparticles shows that it is well suited for electrode material of super capacitors. • Room temperature ferromagnetism was observed in both pure and Co doped NiO samples. • Doping of transition metal ion like Co in NiO sites enhances its electrochemical behavior. - Abstract: Co doped NiO nanoparticles Co_xNi_1-xO (x = 0.0, 0.1, 0.2, 0.3, 0.4) were synthesized by the Sol-gel technique. The impact of Co doping concentration on structural, functional and magnetic properties of NiO nanoparticles was analyzed by X-ray diffraction (XRD), FESEM with EDAX, FTIR and VSM. The average crystallite size was measured to be 34 nm and 11 nm for NiO and Co doped NiO nanoparticles respectively. FESEM reveals that particles are spherical in shape with average size around 30 nm. The elemental composition was analyzed by EDAX. FTIR spectra reveal the existence of NiO peaks in the prepared samples, room temperature ferromagnetism was observed for pure and Co doped NiO nanoparticles by VSM. Pure NiO particles shows ferromagnetic behavior with low coercivity and it increases gradually when doping ratio increases. Higher saturation magnetization was obtained for the sample 0.1 M of Co doped NiO nanoparticle as 22.09 emu/gm. An attempt has been made to study the pseudocapacitance behavior of pure and Co doped NiO nano particles in various scan rates. Electrochemical studies show that 0.4 M Co doped sample gives better charge storage capacity with maximum specific capacitance of 379 Fg⁻¹ at a scan rate of 20 mVs⁻¹. It reveals that it is a promising electrode material for super capacitor applications.