Facile synthesis and properties of chromium-doped cobalt oxide (Cr-doped Co3O4) nanostructures for supercapacitor applications

Chromium-doped cobalt oxide (Crx-doped Co3O4x = 1–10 at%) nanoflowers were synthesized by a facile hydrothermal method. The structure, morphology, composition, and optical properties were analyzed with X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray, and photoluminescence spectroscopy. The electrochemical properties of the chromium-doped cobalt oxide (Crx-doped Co3O4x = 1–10 at%) nanoflowers were measured by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in 3 M KOH electrolyte. The 6 at% Cr-doped Co3O4 sample has demonstrated 1283 Fg−1 specific capacitance at 5 mV/s scan rate which is 67% more than pristine Co3O4 having specific capacitance 860.56 Fg−1. Moreover, it has presented outstanding specific capacitance retention of 72.86% after 1000 continuous charge–discharge cycles. These excellent electrochemical properties of 6 at% chromium-doped cobalt oxide (Crx-doped Co3O4x = 6 at%) nanoflowers showed that it is promising material for supercapacitor applications.