Search

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]

Abstract: A hierarchically porous cobalt oxide (Co3O4) array film, in which the skeleton is composed of ordered non-close-packed bowl array possessing nanoporous walls, is successfully prepared by electrodeposition through self-assembled monolayer polystyrene sphere template. As an anodic coloring material for electrochromic application, the hierarchically porous Co3O4 array film exhibits enhanced electrochromic properties with higher optical modulation, faster switching speed and better cycling performance, compared to dense Co3O4 film. The porous Co3O4 array film presents a quite good transmittance modulation with 42% in the visible range and also shows good reaction kinetics with fast response time of about 2s, much higher than those of the dense film (25% and 4.5s). The better electrochromic performances of the porous film are attributed to its highly porous morphology, which shortens the ion diffusion paths and provides bigger surface area. [Copyright &y& Elsevier]

Abstract: A porous nanowall Co3O4 film is prepared by a facile cathodic electrodeposition. The as-prepared porous nanowall Co3O4 film shows a net-like porous structure with huge porosity. The porous network is made up of free standing interconnected Co3O4 nanoflakes with a thickness of 20nm. As cathode material for pseudocapacitors, porous nanowall Co3O4 film exhibits weaker polarization, higher electrochemical reactivity and better cycling performance as compared to the dense Co3O4 film. The specific capacitance of porous nanowall Co3O4 film is 325Fg−1 at 2Ag−1 and 247Fg−1 at 40Ag−1, respectively, much higher than that of the dense Co3O4 film (230Fg−1 at 2Ag−1 and 167Fg−1 at 40Ag−1). The better pseudocapacitive performances of the porous nanowall Co3O4 film are attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, and relaxes the volume change caused by the reaction during the cycling process. [Copyright &y& Elsevier]

Abstract: Self-organized macroporous tungsten trioxide (WO3) films are obtained by anodic oxidation of DC-sputtered tungsten (W) layers on 10mm×25mm indium tin oxide (ITO)-coated glass. Under optimized experimental conditions, uniformly macroporous WO3 films with a thickness of ca. 350nm are formed. The film shows a connected network with average pore size of 100nm and a pore wall thickness of approximately 30nm. The anodized film becomes transparent after annealing without significant change in macroporous structure. In 0.1M H2SO4, the macroporous WO3 films show enhanced electrochromic properties with a coloration efficiency of 58cm2 C−1. Large modulation of transmittance (∼50% at 632.8nm) and a switching speed of about 8s are also achieved with this macroporous film. [ABSTRACT FROM AUTHOR]

Abstract: Highly ordered porous Cu2O film is electrodeposited on copper foil through a self-assembled polystyrene sphere template. Compared with the dense Cu2O film and the octahedral Cu2O powder, the ordered porous Cu2O film exhibits an improved electrochemical cycling stability. The capacity of the porous Cu2O film can maintain 336mAhg−1 and 213mAhg−1 after 50 cycles at the rate of 0.1C and 5C, respectively. The reversible capacity holds 63.4% as the discharge–charge rate even increases by 50 times. The enhanced high rate properties of the ordered porous film should be attributed to the sufficient contact surface of Cu2O/electrolyte and the short diffusion length of Li+. Moreover, the direct contact between Cu2O and current collector and the decreasing inactive interfaces of Cu2O/polymer binder are also suggested as being responsible for the enhanced high rate property. [Copyright &y& Elsevier]

Abstract: Well-crystallized FeS2 powders are synthesized via solid state reaction. Influence of particle size on electrochemical performances has been conducted. Compared with other anode materials, FeS2 powder with mean particle size of 0.28μm exhibits high coulombic efficiency, initial discharge specific capacity, low polarization and enhanced electrode process kinetics. The enhanced electrochemical properties are attributed to the dense powder packing, better electrical contact and relative stable structure during cycling process. Smaller FeS2 particles (0.078 and 0.071μm) have difficulty in dispersing and mixing with carbon black and binder and less dense packing state, leading to a decrease of reactive contact surface area and poor electrochemical performance. [Copyright &y& Elsevier]

Abstract: Highly porous nickel oxide (NiO) thin films were prepared on ITO glass by chemical bath deposition (CBD) method. SEM results show that the as-deposited NiO film is constructed by many interconnected nanoflakes with a thickness of about 20nm. The electrochromic properties of the NiO film were investigated in a nonaqueous LiClO4–PC electrolyte by means of optical transmittance, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The NiO film exhibits a noticeable electrochromic performance with a variation of transmittance up to 38.6% at 550nm. The CV and EIS measurements reveal that the NiO film has high electrochemical reaction activity and reversibility due to its highly porous structure. The electrochromic (EC) window based on complementary WO3/NiO structure shows an optical modulation of 83.7% at 550nm, much higher than that of single WO3 film (65.5% at 550nm). The response time of the EC widow is found to be about 1.76s for coloration and 1.54s for bleaching, respectively. These advantages such as large optical modulation, fast switch speed and excellent cycle durability make it attractive for a practical application. [Copyright &y& Elsevier]