Temperature Controlled Synthesis of Ce-MnO2 Nanostructure: Promising Electrode Material for Supercapacitor Applications

The objective of this study was to prepare Ce-MnO2 nanostructure composite as an electrode material for supercapacitor application. Ce-MnO2 nanostructure composite was synthesized by facile hydrothermal method at different temperatures. Structural details of pure and Ce-MnO2 nanostructure composite were studied using powder X-ray diffraction technique. The formation of flower like structure and strong interaction with Ce and MnO2 were confirmed by field emission electron microscope technique. Their electrochemical performances were elucidated by using cyclic voltammetry, charge-discharge, and electrochemical impedance spectroscopy techniques. Nearly rectangular shaped cyclic voltagram was observed for synthesized Ce-MnO2 nanostructure composite electrode, indicating the existence of electric double layer capacitance nature. Ce-MnO2 (130) nanostructure composite exhibited high specific capacitance value of 147.25 F/g at applied current density of 1 A/g in 1 M Li2SO4 aqueous electrolyte. Furthermore, resistive and capacitive behaviors of these electrodes were studied from Nyquist and bode diagrams within frequency range of 10 mHz to 100 kHz.