Preparation and electrochemical performance of the layered cobalt oxide (Co3O4) as supercapacitor electrode material

Layered Co3O4 composed of oriented self-assembled micrometer-length rectangular 2D flakes has been successfully synthesized by a hydrothermal method in combination with subsequent calcination process. Structural and morphological characterizations were performed using powder X-ray diffraction and field emission scanning electron microscopy. The component and thermal stability of the sample were measured by FT-IR and thermal analyses, including thermogravimetry and differential thermal analysis. The electrochemical performances of the as-prepared Co3O4 product were investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and constant current charge/discharge techniques. The electrochemical results demonstrate that the layered Co3O4 product displays good capacitive behavior with a specific capacitance of 263 F g(-1) within a potential range of -0.4-0.55 V at a current density of 1 A g(-1) and a large capacity retention with 89.4 % of the initial capacitance over 1,000 consecutive cycles at 3 A g(-1), indicating that the as-prepared Co3O4 product can be a promising electroactive material for supercapacitor.