Synthesis and electrochemical capacitance of mesoporous Co(OH)2

Mesoporous Co(OH)2 was synthesized by using CH3(CH2)10CH2OSO3Na as soft template and urea as hydrolysis-controlling agent. The composition and microstructure of Co(OH)2 was investigated by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and nitrogen adsorption and desorption isotherms. Structure characterizations indicated a good mesoporous structure for the prepared Co(OH)2 with adsorption average pore diameter of 11 nm and Brunauer–Emmett–Teller (BET) specific surface area of 283 m2 g−1. Cyclic voltammogram, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy (EIS) analysis showed that the Co(OH)2 possessed good capacitive behavior. The maximum specific capacitance of 341 F g−1 was obtained for the mesoporous Co(OH)2 at a charge/discharge current density of 5 mA cm−2.