Studies on spray deposited Ni doped Mn^sub 3^O^sub 4^ electrodes for supercapacitor applications

The doping influenced morphological alteration and its consequent impact on electrochemical properties of Mn3O4 electrodes has been investigated. The Ni doped Mn3O4 are characterized for its surface morphological, compositional, structural, optical and electrochemical properties. The polycrystalline nature of Ni doped Mn3O4 films with tetragonal Hausmannite crystal structure has been confirmed from x-ray diffraction. The field emission scanning electron microscope study shows that Ni doped Mn3O4 films have porous nanoflakes type surface morphology. The band gap energy for Ni doped Mn3O4 films ranges between 2.55 and 3.29 eV depending on the Ni doping. The specific capacitance of 705 Fg‒1 from cyclic voltammetry and 740 F g−1 from galvanostatic charge/discharge has been perceived. The Ni doped Mn3O4 electrode show good electrochemical cycling stability. The electrochemical impedance study showed charge transfer resistance of 6.8 Ωcm2 for 0.50 mol % Ni doped Mn3O4 electrode.