Electrochemical Deposited Nanoflakes Co(OH) 2 Porous Films for Electrochemical Capacitors

Nanoflakes Co(OH) 2 porous films have been successfully electrochemical deposited on nickel foam substrate from cobalt nitrate dissolved in water and water‐ethanol (1:1 volume ratio) solutions, respectively. Field emission scanning electron microscope (FESEM) studies indicate that the films electrodeposited from both solutions have nanoflakes porous structure. Cyclic voltammetry (CV) and galvanostaitc charge/discharge measurements show that the Co(OH) 2 films electrode deposited in water‐ethanol solution has excellent electrochemical capacitance between a potential range of 0‐0.4 V, and the maximum specific capacitance as high as 2369 F g −1 could be achieved in 2 M KOH solution at a charge‐discharge current density of 2 A g −1 , suggesting its potential application in the electrode material for electrochemical capacitors. Meanwhile, the properties of the nanoflakes Co(OH) 2 porous films electrodeposited in water solution are also discussed for comparison.