Ultralayered Co₃O₄ for High-Performance Supercapacitor Applications

Abstract

Ultralayered Co₃O₄ structures with high porosity have been synthesized by a facile homogeneous precipitation process under hydrothermal conditions. The superstructures consist of well-arranged micrometer length rectangular 2D flakes with high specific surface area, pore volume, and uniform pore size distribution. The electrochemical measurements demonstrate that charge storage occurs in ultralayered Co₃O₄ due to reversible redox reactions. The charge–discharge study shows that the material is capable of delivering very high specific capacitance of 548 F g^–1 at a current density of 8 A g^–1 and retains 66% of capacitance at 32 A g^–1. The charge–discharge stability measurements show excellent specific capacitance retention capability, ca. 98.5% after 2000 continuous charge–discharge cycles at high current density of 16 A g^–1. The exceptional cyclic, structural, and electrochemical stability at higher current rate with ∼100% Coulombic efficiency, and very low ESR value from impedance measurements promise good utility value of ultralayered Co₃O₄ material in fabricating a wide range of high-performance electrochemical supercapacitors.