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Abstract: 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 20nm. The pseudocapacitive behavior of the porous composite film is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge tests in 1M KOH. The porous β-Ni(OH)2/γ-NiOOH composite film exhibits a noticeable pseudocapacitance with 1420Fg−1 at 2Ag−1 and 1098Fg−1 at 40Ag−1, respectively, much higher than those of the dense Ni(OH)2 film (897Fg−1 at 2Ag−1 and 401 at 40Ag−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. [Copyright &y& Elsevier]

Abstract: Highly ordered porous NiO film is prepared by self-assembled monolayer polystyrene sphere template-assisted electrodeposition. The as-prepared NiO film shows an ordered hexagonal close-packed bowel-like array that is made up of macrobowls with about 500nm in diameter. The electrochromic properties of NiO film are investigated in an aqueous alkaline electrolyte (0.1M KOH) by means of transmittance, cyclic voltammetry and chronoamperometry measurements. The ordered porous NiO film prepared with PS sphere template exhibits a noticeable electrochromism with reversible color changes from transparent to dark brown, and presents quite good transmittance modulation with a variation of transmittance up to 76% at 550nm. The ordered porous NiO film also shows high coloration efficiency (41cm2 C−1), fast switching speed (3s and 6s) and good cycling performance, compared with the dense NiO film prepared without PS sphere template. The improvements of electrochromic performances are attributed to the highly porous morphology, which shortens the ion diffusion paths and provides bigger surface area. [Copyright &y& Elsevier]