Facile approach to prepare loose-packed cobalt hydroxide nano-flakes materials for electrochemical capacitors

Abstract Cobalt hydroxide nano-flakes are successfully synthesized by a facile chemical precipitation method. Electrochemical characterization is performed using cyclic voltammetry, chronopotentiometry and impedance spectroscopy, respectively. These cobalt hydroxide nano-flakes maintain high utilization at high rates of discharge. A maximum specific capacitance of 735 F g −1 can be achieved in 2 M aqueous KOH with the potential range from −0.2 to 0.4 V (vs. SCE) in a half-cell setup configuration for the nano-flakes Co(OH) 2 electrode, suggesting its potential application in electrochemical capacitors. Furthermore, the effect of annealing temperatures on the electrochemical capacitance characteristics is also been systematically explored.