Nano hexagonal Co3O4 platelets for supercapacitor applications—synthesis and characterization

Abstract

Co3O4 hexagonal platelets were synthesized by simple low-cost chemical oxidation method without any surfactant. Structural and morphological analysis was carried out by XRD, FTIR, FESEM and TEM measurements. Paramagnetic nature of the samples was confirmed from VSM analysis. SAED and intensity translated spectra were indexed and matching with the XRD phase. The thermal stability of the samples was tested by using thermogravimetric experiment and showed the stability up to 760 °C. The hexagonal Co3O4 platelets were used to analyze the electrochemical characteristics for supercapacitor applications and the highest specific capacitance was observed as 718 F g−1 with a current density of 1 A g−1. The capacitance retention capacity was studied by cyclic stability of the prepared electrode materials up to 4000 cycles and showed 96% of capacity retention. The Impedance spectra was measured before and after completing the cyclic stability measurement and interpreted with the electrochemical behavior of Co3O4 hexagonal platelets. Two electrodes cell is fabricated to analyze the electrochemical characteristics and the asymmetric cell showed a highest specific capacitance of 66 F g−1 with an applied current load of 1 A g−1. The highest energy density of 23.35 Wh K−1g−1 was observed with a power density of 560 W K−1g−1. The physical and electrochemical characteristics of the hexagonal Co3O4 platelets in three electrodes and two electrodes asymmetric device are discussed in detail. The present synthesis method could be extended for the synthesis of other electrode materials to obtain a novel morphology.