Impact of doping of cobalt on electrochemical properties of Cr2O3 for high performance supercapacitor applications

Pristine chromium oxide and cobalt-doped (1 %, 3 %, and 5 %) chromium oxide nanoparticles were synthesized by the facile auto-combustion method. The electrochemical characterization was performed using galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV). The XRD patterns of both pristine Cr 2 O 3 and Co-doped Cr 2 O 3 were indexed to a rhombohedral structure with an R-3c space group without any impurity peaks. Optical band gap of Cr 2 O 3 is redshifted from 2.96 eV to 2.64 eV with Co incorporation into the host lattice. TEM analysis confirms the formation of Cr 2 O 3 spherical nanoparticle with better crystallinity and it deteriorates with Co doping. The N 2 adsorption desorption studies show that BET specific surface area found to be decreased from 40.93 to 24.56 m 2 /g by the incorporation of Co into the Cr 2 O 3 host lattice. When subjected to the current density of 1 Ag −1 , the Cr 2 O 3 nanoparticle exhibited a specific capacity of about 151 Cg −1 revealed under the galvanostatic charge discharge investigations. The remarkable electrochemical performance of Cr 2 O 3 suggests that the electrode material has the potential to produce favorable electrodes that are competent for use in energy storage devices.