Search

Abstract: We report a silicon/graphene-sheet hybrid film prepared by combining electrophoretic deposition and radiofrequency magnetron deposition methods. The constructed hybrid film shows rough morphology with wrinkles and scrolling edges. As anode material for lithium ion batteries, the silicon/graphene-sheet hybrid film exhibits enhanced electrochemical performances with weaker polarization, higher capacity, better rate capability and cycling performance as compared to the bare silicon film. The silicon/graphene-sheet hybrid film delivers a high initial reversible capacity of 2204mAhg−1 and quite good cycling life (capacity maintenance is 87.7%) after 150cycles. The graphene-sheet in the hybrid film is responsible for the improvement of the electrochemical properties. The introduction of the graphene-sheet film not only enhances the adhesion between silicon and the current collector, but also alleviates the structure degradation caused by volume expansion and the shrinkage of silicon film during lithium-ion insertion/extraction, resulting in improved electrochemical performances. [Copyright &y& Elsevier]

Abstract: A three-dimensional (3D) porous nano-Ni supported Si composite film is successfully fabricated by the combination of hydrogen bubble template electrodeposition of porous nano-Ni film and radiofrequency magnetron sputtering amorphous silicon. As anode for lithium-ion batteries, the 3D porous Ni/Si composite film shows noticeable electrochemical performance with high capacity of 2444mAhg−1 at a current density of 0.84Ag−1, superior capacity retention of 83% after 100 cycles, as well as excellent rate capability with 1420 and 1273mAhg−1 at charge–discharge current densities of 4.2Ag−1 and 8.4Ag−1 after 100 cycles, respectively. The enhanced electrochemical performance is mainly attributed to the highly porous conductive architecture, which provides good mechanical support and electron conducting pathway for active silicon and alleviates the structure degradation caused by volume expansion during the cycling process. [Copyright &y& Elsevier]

Abstract: It is highly desirable to induce significant red-shift in the optical absorption edges of TiO2 phases so that this class of low-cost and environmentally friendly materials can be used as effective optical absorbing materials in novel photovoltaic cells with long-term sustainability or smart photo-catalysts beyond the ultraviolet range. This work focuses on studying the mechanisms of Mn-induced red-shift by combining theoretical modeling with advanced structural and spectroscopic characterization of doped thin films, aiming to provide fundamental guidance for effective doping through enhanced understanding of doping chemistry resulting from the interplay between doping atoms and defects. It is shown that Mn atoms doped into the Ti lattice sites are associated with oxidation valency higher than +3, resulting in maximized effectiveness in modifying the band structure to achieve remarkable optical red-shifting. The presence of oxygen vacancies reduces the Mn valency and its red-shifting effect, but their detrimental effect in bringing about localized defect levels is reduced owing to their association with Mn atoms, making Mn doping highly promising in activating various visible light functionalities of TiO2. [Copyright &y& Elsevier]

Abstract: A hierarchically porous NiO film on nickel foam substrate is prepared by a facile ammonia-evaporation method. The self-assembled film possesses a structure consisting of NiO triangular prisms and randomly porous NiO nanoflakes. The pseudocapacitive behaviors of the porous NiO film are investigated by cyclic voltammograms and galvanostatic charge–discharge tests in 1M KOH. The hierarchically porous NiO film exhibits a high discharge capacitance and excellent rate capability with 232Fg−1, 229Fg−1, 213Fg−1 and 200Fg−1 at 2, 4, 10, and 20Ag−1, respectively. The specific capacitance of 87% is maintained from 2Ag−1 to 20Ag−1. The porous NiO film also shows rather good cycling stability and exhibits a specific capacitance of 348Fg−1 after 4000 cycles. [Copyright &y& Elsevier]

Abstract: Hierarchically porous Co3O4 film is prepared by a cathodic electrodeposition via liquid crystalline template. The as-prepared Co3O4 film has a net-like structure of interconnected nanoflakes with a thickness of 15–20nm. Interestingly, the Co3O4 nanoflakes possess mesoporous walls ranging from 2 to 3nm. As cathode material for supercapacitors, the hierarchically porous Co3O4 film exhibits superior supercapacitor performances with high specific capacitances (443Fg−1 at 2Ag−1 and 334Fg−1 at 40Ag−1) as well as excellent cycle life, making it suitable for high-performance supercapacitor application. The improved supercapacitor performances are due to its unique hierarchically porous morphological characteristics, which provide fast ion and electron transfer, large reaction surface area, resulting in fast reaction kinetics. [Copyright &y& Elsevier]

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 highly porous cobalt oxide thin film was prepared on ITO glass by a facile chemical bath deposition (CBD) method. The as-prepared cobalt oxide film has an intercrossing net-like morphology. The electrochromic performance of cobalt oxide film was investigated in 0.1MKOH by means of transmittance, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The cobalt oxide thin film exhibits a noticeable electrochromism with reversible color changes from pale yellow to dark grey and presents a transmittance variation with 36% in the visible range. The porous cobalt oxide thin film also shows good reaction kinetics with fast switching speed, and the coloration and bleaching time are 2.5 and 2s, respectively. [Copyright &y& Elsevier]

Abstract: NiO thin films on ITO substrate were prepared by chemical bath deposition (CBD) and sol–gel method, respectively. The microstructure and morphology of the NiO films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Both the films have polycrystalline cubic NiO, but have distinct morphology. The CBD NiO thin film with a highly porous structure exhibited a noticeable electrochromic performance. The variation of transmittance was high up to 82% at 550nm and the coloration efficiency (CE) was calculated to be 42cm2 C−1. The sol–gel NiO thin film with a smoothly compact structure presented 35% and 28cm2 C−1 at 550nm, respectively. The electrochemical properties of both the NiO thin films were investigated in 1M KOH electrolyte by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The CV and EIS measurements revealed that the CBD NiO thin film had better electrochemical reversibility, higher reactivity and reaction kinetics due to its highly porous structure. [Copyright &y& Elsevier]

Abstract: Hexagonal structured WO3 films with tree-like morphology were synthesized on tungsten foils by a hydrothermal method. Each nanotree was composed of several (typically six) nanosheet-shaped “branches”. TEM examination revealed that the nanosheet was a single crystal and its long axis was oriented toward 〈001〉 direction. The WO3 nanotree films retain the hexagonal structure after being annealed up to 400°C for 2h, while they have a phase transition to monoclinic structure after being annealed at 500°C for 2h. Electrochromic (EC) performance of the films was examined in a propylene carbonate solution of 1M LiClO4 using an electrochemical workstation and an UV–Vis spectrometer. Due to the large tunnels of hexagonal structure and highly porous surface morphology, a large modulation of optical reflectance of WO3 nanotree films up to 30% and coloration efficiency of 43.6cm2 C−1 at 500nm were achieved by annealing the WO3 nanotree films at 400°C for 2h. [Copyright &y& Elsevier]

Abstract: Co-doped NiO nanoflake arrays with a cellular-like morphology are fabricated by low temperature chemical bath deposition. As anode material for lithium ion batteries (LIBs), the array film shows a capacity of 600mAhg−1 after 50 discharge/charge cycles at low current density of 100mAg−1, and it retains 471mAhg−1 when the current density is increased to 2Ag−1. Appropriate electrode configuration possesses some unique features, including high electrode–electrolyte contact area, direct contact between each naonflake and current collector, fast Li+ diffusion. The Co2+ partially substitutes Ni3+, resulting in an increase of holes concentration, and therefore improved p-type conductivity, which is useful to reduce charge transfer resistance during the charge/discharge process. The synergetic effect of these two parts can account for the improved electrochemical performance. [Copyright &y& Elsevier]

Abstract: NiO film with sandwich-like morphology is fabricated on nickel foam by a simple ammonia-evaporation process. Ammonia plays a major role in controlling the final geometry during this template- and surfactant-free synthesis. The obtained NiO film is constructed by regular triangular prisms with side length of 500nm. Each triangular prism is self-assembled by single crystalline platelets. As an anode for lithium ion battery, this NiO film electrode exhibits high discharge capacity and excellent cycling performance. The reversible capacity of the sandwich-like NiO film sustains 400mAhg−1 even after 50 cycles at 2C, much higher than that of the dense NiO film prepared by eletrodeposition (198mAhg−1). The high rate capability and reversibility of this NiO film can be attributed to its unique sandwich-like architecture. [Copyright &y& Elsevier]

Abstract: Highly ordered porous Ni3P film was successfully electrodeposited through a self-assembled monodisperse polystyrene sphere template on copper substrate after heat treatment. The spherical pores left in the film after the removal of polystyrene spheres are well-ordered and close-packed. The diameter of the pores arranged in the film is about 800nm and the thickness of the wall connecting adjacent pores is 60nm. As anode for lithium ion batteries, the nanostructured porous Ni3P film exhibits improved capability and reversibility over the dense one. After 50 cycles, the reversible capacity of the porous Ni3P film is 403mAhg−1 and 239mAhg−1 at 0.2C and 2C, maintaining 78.1% and 67.9% of the capacity in the 2nd cycle, respectively. The enhanced electrochemical performance of the porous film is attributed to the better contact between Ni3P and electrolyte, which provides more sites for Li+ accommodation, shortens the diffusion length of Li+ and enhances the kinetics of electrode process. Moreover, the porous structure is stable and can sustain well even after 50 cycles. [ABSTRACT FROM AUTHOR]

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: NiO/poly(3,4-ethylenedioxythiophene) (PEDOT) films are prepared by chemical bath deposition and electrodeposition techniques using nickel foam as the substrate. These composite films are porous, and constructed by many interconnected nanoflakes. As anode materials for lithium ion batteries, the NiO/PEDOT films exhibit weaker polarization and better cycling performance as compared to the bare NiO film. Among these composite films, the NiO/PEDOT film deposited after 2 CV cycles has the best cycling performance, and its specific capacity after 50 cycles at the current density of 2C is 520mAhg−1. The improvements of these electrochemical properties are attributed to the PEDOT, a highly conductive polymer, which covers on the surfaces of the NiO nanoflakes, forming a conductive network and thus enhances the electrical conduction of the electrode. [Copyright &y& Elsevier]

Fabricating advanced cathode is critical for the development of high-performance lithium ion batteries (LIBs). In this work, we develop a facile hydrothermal method for construction of LiFePO 4 /N-C films on the carbon cloth forming integrated binder-free cathode. The LiFePO 4 /N-C films are composed of interconnected nanoscale LiFePO 4 /N-C particles with diameters of 100–200 nm. High porosity and good adhesion are obtained in the carbon cloth supported LiFePO 4 /N-C films (CC + LiFePO 4 /N-C films). As compared to the LiFePO 4 /C powder nanoparticles, the CC + LiFePO 4 /N-C films show much better electrochemical properties with higher capacities, smaller polarization and better high-rate cycling life. A high capacity of 169 mAh g −1 at 1C is achieved for the carbon cloth supported LiFePO 4 /N-C films, superior to the LiFePO 4 /C powder nanoparticles (154 mAh g −1 at 5C). This enhancement is owing to the unique integrated porous architecture and N-C coating. Our work shows a new way to construct integrated cathode for application in LIBs. [ABSTRACT FROM AUTHOR]

Abstract: Mg–Ni multilayer films with sequential Mg and Ni layers were prepared by direct current magnetron sputtering. The substrate temperature influences the microstructure of the films greatly. The film deposited at 298K exhibits multilayered structure, while the film shows nanocrystalline/amorphous composite structure at the deposition temperature of 473K. The optical properties between hydrogenation/dehydrogenation states of the films were performed using spectrophotometer in visible light region. The film deposited at 473K can switch from mirror-like metallic state towards brownish yellow transparent state under 0.6MPa H2 at 298K, and the optical transmittance modulation reaches up to 20% both at a wavelength of 770nm and IR region, while the film deposited at 298K exhibits low optical change, and the optical switching behavior can hardly be found. The extra free energy stored in the boundary of the nanocrystallines benefits the formation of magnesium-based hydride, resulting in the enhancement of the optical switching properties of the Mg–Ni film deposited at 473K. [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]

Abstract: Ni3P–Ni films were deposited on nickel foam substrates by electrodeposition in an aqueous solution. The structure and morphology of the electrodeposited films were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The annealed electrodeposited films consisted of tetragonal structured Ni3P and cubic metal Ni. As anode for lithium ion batteries, the electrochemical properties of the Ni3P–Ni films were investigated by cyclic voltammetry (CV), electrochemical impedance spectrum (EIS) and galvanostatic charge–discharge tests. The electrodeposition time had a significant effect on the electrochemical performances of the films. The Ni3P–Ni film electrodeposited for 20min delivered the initial discharge capacity of 890mAhg−1. Although the irreversible capacity at the first cycle was relative large, the Ni3P–Ni film exhibited good cycling stability and its discharging capacity still maintained 340mAhg−1 after 40 cycles. [Copyright &y& Elsevier]