Electrodeposition of ordered mesoporous cobalt hydroxide film from lyotropic liquid crystal media for electrochemical capacitors

A novel ordered mesoporous cobalt hydroxide film (designated H-I-e Co(OH)(2)) has been successfully electrodeposited on titanium substrate from the hexagonal lyotropic liquid crystalline phase using surfactant Brij 56 as the structure-directing agent. Low-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies indicate that the film electrodeposited from the liquid crystal template has a regular nanostructure consisting of a hexagonal array of cylindrical pores. Cyclic voltammeter (CV) and galvanostatic charge/discharge measurements show that the ordered mesoporous H-I-e Co(OH)(2) film electrode has excellent electrochemical capacitance between a potential range of - 0.1 - 0.45 V, and a maximum specific capacitance as high as 1084 F g(-1) could be achieved in 2 M KOH solution at a charge - discharge current density of 4 A g(-1). Meanwhile, the properties of Co(OH)(2) film electrodeposited from aqueous solution without templates (designated Aq-e Co(OH)(2)) are also discussed for comparison.