Nickel foam-supported porous Ni(OH)2/NiOOH composite film as advanced pseudocapacitor material

A porous net-like β-Ni(OH)2/γ-NiOOH composite film is prepared by a chemical bath deposition. The as-prepared porous composite film shows a highly porous structure built up by many interconnected nanoflakes with a thickness of about 20 nm. The pseudocapacitive behavior of the porous composite film is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge tests in 1 M KOH. The porous β-Ni(OH)2/γ-NiOOH composite film exhibits a noticeable pseudocapacitance with 1420 F g−1 at 2 A g−1 and 1098 F g−1 at 40 A g−1, respectively, much higher than those of the dense Ni(OH)2 film (897 F g−1 at 2 A g−1 and 401 at 40 A g−1). The porous architecture is responsible for the enhancement of the electrochemical properties, and it increases electrochemical reaction area, shortens ions diffusion paths and relaxes volume change caused by the electrochemical reactions.