Abstract
Nanoarchitecture of transition metal oxides has been deemed to play an important role in the supercapacitor electrode material. In this regard, transition metal (Ni, Mn, and Zn) doped Co
3
O
4
has been synthesized using a facile co-precipitation technique. X-ray diffraction analysis revealed the face-centered cubic lattice of Co
3
O
4
with slight variation in lattice parameters when iso-valent metals are doped at the Co site. Densely packed spherical grains of pure Co
3
O
4
with an average grain size of 50 nm are observed. However, the incorporation of a nominal amount of Ni, Mn, and Zn at Co-site resulted in a favorable porous morphology. Therefore increasing porosity with substitution and presence of constituent elements is noticed from the scanning electron microscope and elemental mapping, respectively. Electrochemical measurements including cyclic voltammetry, galvanostatic charge-discharge curves, and electrochemical impedance spectroscopy are carried out in 4 M KOH solution in three-electrode systems. It has been observed that all electrode materials displayed typical pseudocapacitive dominant behavior but it is more obvious in Mn
0.05
Co
2.95
O
4
. This composition also exhibited the highest value of specific capacitance of 80.8 F/g at the current density of 1 A/g. Therefore, based on the calculated values of energy and power density we claim that the Mn
0.05
Co
2.95
O
4
is a potential candidate for electrochemical supercapacitor applications.
Graphical abstract
Highlights
Transition metal doped Co
3
O
4
prepared by sol-gel auto combustion method.
Structural analysis revealed the formation of single-phase spinel structure of all compositions.
SEM and EDX investigations exhibited the flower-like morphology and elemental purity of pure Co
3
O
4
.
Specific capacitance, energy density, and power density have been evaluated and potential as an electrode material for supercapacitor.