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

Abstract

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.