Hydrothermal synthesis of cerium-doped Co₃O₄ nanoflakes as electrode for supercapacitor application

In this work, cerium was doped in various concentrations ranging from 1.0 to 7.0 at. % by means of a facile hydrothermal synthesis route with an intention to improve the capacitive properties of Co₃O₄. X-ray powder diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (EDX) and HRTEM were employed to study the structural characteristics, morphology, elemental constitution and d-spacing of the synthesized material. The capacitive characteristics were analyzed through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) test and electrochemical impedance spectroscopy (EIS). Materials characterizations revealed the formation of pristine and Ce-doped Co₃O₄ nanoflakes, and their average size was in the range of 45 to 55 nm and possessing excellent elemental purity. The CV test showed that 5.0 at. % Ce-doped Co₃O₄ nanoflakes deliver outstanding specific capacitance, that is, 1309.6 F/g and excellent cyclic stability of 90.86% after 2000 CV cycles at a scan rate 5 mV/s. The GCD test at 1-10 A/g showed excellent rate capability, that is, 82.87% at high current density of 10 A/g. The EIS test revealed excellent electrical conductivity of the material. Experimental results suggest that Ce-doped Co₃O₄ has an outstanding potential for use in energy storage devices.