Electrochemical fabrication of Ni(OH)2/Ni 3D porous composite films as integrated capacitive electrodes

Ni(OH)(2) coated on Ni porous films are facilely fabricated by anode oxidation of 3D hierarchical porous Ni films which are prepared through a hydrogen bubble template electro-deposition method. The highly porous nickel films function as effective 3D conductive network current collectors and scaffolds to in situ form a thin layer of Ni(OH)(2) active material. The electrochemical capacitive performances are investigated by cyclic voltammetry (CV) and the galvanostatic charge-discharge technique in 6 M KOH electrolyte. The 3D porous Ni(OH)(2)/Ni integrated electrodes demonstrate a much higher specific capacity of 828 mF cm(-2) than 126 mF cm(-2) for the smooth Ni(OH)(2)/Ni electrode at a current density of 10 mA cm(-2). The 3D porous Ni(OH)(2)/Ni integrated electrodes also display a good capacity retention of 95% after 1000 cycles. The superior capacitive properties of 3D porous Ni(OH)(2)/Ni electrodes might result from the thin layer Ni(OH)(2) active materials in situ formed on the highly 3D porous Ni metallic current collector with large surface area, low contact resistance between Ni(OH)(2) active material and Ni current collector, and fast electron/ion conduction.