As one of the most promising anode materials, MnO2 has attracted much attention due to its much higher theoretical capacity. However, the low electrical conductivity and the large specific volume change limit its performance. Herein we synthesize rodlike MnO2/reduced graphene oxide (RGO) composite for Li-ion batteries by a simple in situ hydrothermal method. The graphene significantly improves the electrical conductivity and buffers the volume change. The composite shows a large reversible capacity and excellent cyclic stability. At the current density of 100 mA g−1, the first discharge and charge capacities are 1469.6 and 879.4 mAh g−1, respectively. After 55 cycles, the rodlike MnO2/RGO composite could deliver reversible capacity as high as 528.7 mAh g−1 at the current density of 100 mA g−1, corresponding to the capacity fading of only 0.8%. The superior electrochemical performance is the joint result of the high capacity of MnO2 and excellent electrical conductivity of RGO.

Hard and optically selective films are useful for low-emissivity applications and the surface layer of optical elements. In this paper, ZrAlN films were prepared by RF magnetron sputtering on glass substrates at room temperature under different power and gas flow rate. Microstructure, optical properties, chemical compositions and tribological properties of the coatings were investigated and the results indicate that the ZrAlN coatings, prepared with a nitrogen flow rate of 6 sccm, target power of 110 W for both Al and Zr, can give an excellent visible light transmittance that allows 90% of light in the range of 400–600 nm to transfer through the glass and films. Especially, the Transmittance of the ZrAlN is 93.4% at the wavelength of 550 nm which is higher than glass. The emissivity of ZrAlN coating is about 0.74, much lower than bare glass. The coatings maintain the optical properties even under salt spray test for 336 h. the results proved that the ZrAlN films are excellent anti-reflective coatings with superior mechanical property and high corrosion resistance, it can be used in low-emissivity glasses and some other optical components.

•An interdigitated CuS/TiO2 nanotube bulk heterojunction was achieved via ion exchange method.•The combination of pre-filling and post-exchanging process is essential in formation of the interdigitated structure.•Such a three-dimensional bulk heterojunction contributes to photovoltaic and optoelectronic applications.In photovoltaic and optoelectronic applications, a three-dimensional bulk heterojunction is highly desirable in view of the large interfacial area for rapid charge separation. An additional benefit of oriented charge transport is furnished when using anodized titania nanotube arrays as the substrates. However, filling the nanotubes with another p-type semiconductor integrate film, rather than discrete nanoparticles, is difficult with solution-based process. In this study, an interdigitated CuS/TiO2 bulk heterojunction was achieved by filling up TiO2 nanotube arrays with ZnS nanoparticles, and subsequently converting the ZnS nanoparticles into CuS film. Such a combination of pre-filling and post-exchanging process is essential in formation of the interdigitated structure. The rational design of the unique architecture demonstrated in this work provides a facile and general approach to fabricate bulk heterojunctions with other potential semiconductors.An interdigitated bulk heterojunction of CuS/TiO2 was fabricated with the assistance of intermediate ZnS nanoparticles subject to ion exchange.Download high-res image (238KB)Download full-size image

Titanium aluminum nitride (TiAlN) coatings were deposited by radio frequency magnetron sputtering on AZ31 magnesium alloy. A microhardness tester, a surface profilometer and an electrochemical systems were used to investigate the hardness, thickness, and corrosion resistance of the coated AZ31 magnesium alloy. XPS showed the presence of different phases such as TiN, TiO2, TiON, AlN, and Al2O3. It demonstrated that TiAlN coatings improved the magnesium alloy’s surface hardness. Furthermore, TiAlN coatings also enhanced the corrosion resistance of the AZ31 magnesium alloy in 3.5 wt% NaCl solution. Corrosion current density decreased from 2.820 × 10−7 A/cm2 for the coated alloy to 1.066 × 10−5 A/cm2 for the uncoated one.

We report on the effect of different ethanol/water solvent ratios on the morphology of SnO2 nanocrystals prepared by the conventional hydrothermal method and their electrochemical properties. The nanocrystals were structurally and morphologically characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), surface area measurements, and transmission electron microscopy. The XRD patterns indicate that the sphere-like SnO2 microcrystals have a rutile-type tetragonal structure and FESEM images show that the microspheres have a diameter of 2–5 μm. We found that the ethanol/water volume ratio plays an important role in formation of the final product. Electrochemical tests revealed that the SnO2 microspheres had a high initial capacity of 1546 mAh g−1 at a current density of 100 mA g−1 and retained a reversible capacity of 439 mAh g−1 after 30 discharge cycles.

A novel SnO2/graphene composite has been synthesized via an in situ chemical synthesis method, in which single crystal SnO2 nanosheets are uniformly grown on graphene support. The as-prepared products were characterized by X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, Thermogravimetric analyses and Nitrogen adsorption/desorption. When used as an anode material for lithium ion batteries, the SnO2/graphene composite exhibits an enhanced reversible lithium storage capacity and good cyclic performance. The first discharge and charge capacities are 1,366 and 975 mAh g−1, respectively. After 100 cycles, the reversible discharge capacity is still maintained at 451 mAh g−1 at the current densities of 100 mA g−1, indicating that it’s a promising anode material for high performance lithium ion batteries.

Graphene was produced via a soft chemistry synthetic route for lithium ion battery applications. The sample was characterized by X-ray diffraction, nitrogen adsorption-desorption, field emission scanning electron microscopy and transmission electron microscopy, respectively. The electrochemical performances of graphene as anode material were measured by cyclic voltammetry and galvanostatic charge/discharge cycling. The experimental results showed that the graphene possessed a thin wrinkled paper-like morphology and large specific surface area (342 m2·g−1). The first reversible specific capacity of the graphene was as high as 905 mA·h·g−1 at a current density of 100 mA·g−1. Even at a high current density of 1000 or 2000 mA·g−1, the graphene maintained good cycling stability, indicating that it is a promising anode material for high-performance lithium ion batteries.

The preparation of amorphous TiO2 film coupled with various metal-oxide semiconductors and their photocatalytic activities evaluated by photo-degradation of methylene blue and rhodamine B aqueous solution are briefly reviewed. The proposed photoreaction mechanism of the amorphous composite semiconductor and the differences between amorphous TiO2-based films and crystalline TiO2 photocatalytic materials in terms of preparation and usage are addressed. The inactive intrinsic amorphous TiO2 film coupled with various metal oxides were found to gain high photocatalytic activity. These dopants induce forming new energy levels in the band gap of TiO2 to enhance the charge separation of the photoinduced electrons and holes and extend the light absorption of TiO2-based photocatalytic films into the visible region. In addition, two different effects of coupling metal oxides have been proved: the introduction of oxides of W, Cr, V, Ag, and Mo can significantly increase the photo-reactivity of amorphous TiO2 film, while the combination of oxides of Zr, Sn, Sb, Cu, Ta, Fe, and Ni cannot affect the inactivity of pure amorphous TiO2 film.

In this work, graphene/self-assembled SnO2 hybrid was prepared via a hydrothermal method. The structure and morphology of graphene/self-assembled SnO2 hybrid were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The XRD analysis confirms the well-crystallized SnO2 in composite. FESEM and TEM studies show the mechanism for the formation of graphene/self-assembled SnO2 hybrid. Due to characteristics of graphene/self-assembled SnO2 hybrid, our findings may have implications in the synthesis and fabrication of well-defined functional graphene/SnO2 hybrid materials. It may also provide a general approach for the preparation of graphene/metal oxide hybrid materials.Highlights► Graphene/self-assembled SnO2 hybrid was synthesized via hydrothermal reactions. ► In the synthesis process, no templates, surface active agents or organic solvents are required. ► TEM image shows that flower-like SnO2 nanorod clusters are single-crystalline.