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A novel ionothermal strategy for developing a chemical conversion film on magnesium alloys is proposed based on the interaction of a deep eutectic solvent (DES) with the substrate. Upon heating the choline chloride/urea mixture-based DES can react with the AZ31B magnesium alloy surface to form a promising anti-corrosion conversion film. Interestingly, the chemical conversion film is mainly composed by MgH 2 and MgCO 3 phases. The as-grown conversion film exhibits superhydrophobicity after surface modification in a stearic acid/ethanol solution. Electrochemical tests and visual investigations indicate the corrosion resistance of the magnesium alloy can be improved by the conversion film. [ABSTRACT FROM AUTHOR]

A novel electrocatalyst for methanol oxidation reaction in alkaline medium is elaborately fabricated by a sponge-template method involving an electroless plating of amorphous Ni–P on sponge and the following annealing process at 500 °C in air. The electrocatalyst is characterized by NiO nanoparticle/nanoflake grown on the Ni–P alloy tube. The vital annealing process aims to remove templates, crystallize Ni–P, and generate NiO nanostructures on the outside surface of Ni–P tubes, thus leading to the final structure of NiO/Ni–P composites. The tubular Ni–P framework surface is decorated with microspherical NiO (EP-M) or nanoflake NiO (EP-F), which strongly depends on the electroless plating time. For comparison, porous NiO nanoflakes are also synthesized by chemical bath deposition. The EP-M containing ∼83.8 wt.% NiO and ∼16.2 wt.% Ni–P has the largest BET surface area of 210.03 m 2 g −1 among the three samples. Moreover, the EP-M exhibits a high current density (∼467 A g −1 ) and long-term chronoamperometry stability (≥20,000 s) toward methanol oxidation in alkaline solution. The improved catalytic activity of the composite catalyst might be attributed to the strong electronic interaction between NiO and Ni–P as revealed by X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: The collective influence of crucial electrodeposition parameters (temperature, deposition voltage and bath composition) on the properties of Zn–Ni films electrodeposited in a choline chloride–urea eutectic-based ionic liquid was investigated. The microstructures, chemical compositions, phase structures and corrosion behaviors of electrodeposited films were analyzed using scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and linear cyclic voltammetry, respectively. The surface morphologies and chemical compositions of the films were strongly dependent on the electrodeposition parameters. It was found that the amounts of nickel in the Zn–Ni alloy films were significantly higher than that present in the electrolytes and was always above 50%, indicating normal codeposition mechanism. Electrodeposition of high Zn content alloy is favorable at high electrodeposition voltages, high temperatures and high Zn (II)/Ni (II) ratios. Electrochemical measurements shows that under the conditions considered, the Zn–Ni film from 0.45M Zn (II)–0.05M Ni (II) deposited at 55°C and 0.8V exhibits the highest barrier corrosion resistance compared with the other films and this was attributed to a dense, smooth and crack free morphology with optimum Zn content. [Copyright &y& Elsevier]

Abstract: Carbon perfectly coated LiFePO4 cathode materials are synthesized by carbon-thermal reduction method using polystyrene (PS) spheres as carbon source. The PS spheres with diameters of 150–300nm used for the pyrolysis reaction not only inhibit the particle growth but also lead to uniform distribution of carbon coating on the surface of LiFePO4 particles. Rate capability and cycling stability of LiFePO4/C with the carbon contents ranging from 1.4wt% to 3.7wt% are investigated at −20°C. The LiFePO4/C with 3.0wt% C exhibits excellent electrochemical capability at low temperature, which delivers 147mAhg−1 at 0.1C. After 100 cycles at a charge–discharge rate of 1C, there is still 100% of initial capacity retained for the LiFePO4/C electrode at −20°C. According to the transmission electron microscope analysis and cyclic voltammetry measurement, this can be attributed to the good carbon coating morphology and optimal carbon coating thickness. [Copyright &y& Elsevier]

Abstract: This work attempts to reveal the microstructure of interface and the relation between interface mixing and hardening mechanism in TiN/CNx multilayer films. The growth and microstructure of these interfacial layers are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Investigation result indicates that the interface species are mainly composed of Ti–C–N, the growth of interlayer mainly depends on the deposition temperature. The thickest interlayer (about 2.5nm) is produced at 300°C, and the interlayer disappears at 500°C. Nanoindentation testing indicates that the film with a maximum interlayer thickness of about 2.5nm exhibits superhardness up to 40GPa. Based on the experimental results, it is suggested that the interfacial intermixing and the crystal quality of TiN are the main reasons for the superhardness effect in TiN/CNx nanostructured multilayers. [ABSTRACT FROM AUTHOR]

Abstract: TiN/CN x multilayer films with bilayer periods of 4.5–40.3nm were deposited by direct-current magnetron sputtering. Layer morphology and structure of the multilayered films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The TiN/CN x multilayers exhibited coherent epitaxial growth due to the mutual growth-promoting effect at small bilayer period and some crystalline regions going through the interface of TiN/CN x . Nanoindentation tests showed that the hardness of the multilayers varied from 12.5 to 31GPa, with the highest hardness being obtained with a bilayer period of 4.5nm. The tribological properties of the films were investigated using a ball-on-disk tribometer in humid air, and the TiN/CN x multilayer with a bilayer period of 4.5nm also exhibited the lowest friction coefficient and the highest wear resistance. [Copyright &y& Elsevier]

Graphical abstract Abstract Exploring high performance cathode materials is of great means for the development of bi-functional electrochromic energy storage devices. Herein, Nb-doped WO 3 mesoporous films as integrated high-quality cathode are successfully constructed via a facile sol-gel method. Chemical state and crystallinity of the WO 3 based films are significantly influenced by doping concentration. Compared with the pure WO 3 , the optimal Nb-doped film shows improved optical-electrochemical properties with high specific capacity (74.4 mAh g−1 at 2 A g−1), excellent high-rate capability, large optical contrast (61.7% at 633 nm), and ultra-fast switching speed (3.6 s and 2.1 s for coloring and bleaching process, respectively). These positive features suggest the potential application of Nb-doped WO 3 mesoporous cathode. Our research paves the way for the development of multifunctional photoelectrochemical energy devices. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 nanorods are synthesized by combustion method using alcohol as both solvent and fuel, which is a facile and effective strategy for the large-scale and inexpensive fabrication. The Fe 2 O 3 nanorods are with the well distributed diameters of 20–30 nm and length ranging from 80 to 100 nm. As an anode material for lithium-ion batteries, the Fe 2 O 3 nanorod electrode delivers a high discharge capacity of 761.7 mA h g −1 after 60 cycles at 500 mA g −1 , and 727.2 mA h g −1 at a high current density of 2000 mA g −1 . The good electrochemical performance is attributed to the sufficient contact of active material and electrolyte, large surface area, and short diffusion length of Li + . [ABSTRACT FROM AUTHOR]

Abstract: Novel Li1.2Mn0.5Co0.25Ni0.05O2 microcube is prepared through a simple binary template method. After calcined at 800 °C, lithium and nickel are permeated into the cathode material and a well-crystallized Li-rich layered oxide is obtained. Furthermore, hollow circle cube architecture is formed due to the decomposing of the carbonate. As a cathode material for lithium ion batteries (LIBs), the oxide with such architecture can deliver high initial discharge capacity of 272.9 mAh g−1 at a current density of 20 mA g−1. High reversible discharge capacities of 208 mAh g−1 and 110 mAh g−1 are obtained at a current density of 200 mA g−1 and 2000 mA g−1, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are performed to further study the hollow Li1.2Mn0.5Co0.25Ni0.05O2 microcube. It is remarkable that such architecture makes the Li-rich layered oxide Li1.2Mn0.5Co0.25Ni0.05O2 a promising cathode material for LIBs. [Copyright &y& Elsevier]

A porous Co3O4 nanoflake array film grown on nickel foam is prepared by a hydrothermal synthesis for pseudo-capacitor application. The pseudocapacitive behavior of the Co3O4 nanoflake array is investigated by cyclic voltammograms (CV), galvanostatic charge–discharge tests and electrochemical impedance spectroscopy (EIS) in 2 M KOH at different temperatures. The specific capacity is 210, 289 and 351 F g−1 at 2 A g−1 tested at −5 °C, 25 °C and 60 °C, respectively, corresponding to that of 184, 243 and 242 F g−1 at 20 A g−1. After 4000 cycles at 2 A g−1, the remaining specific capacity is 187, 342 and 124 F g−1 tested at −5 °C, 25 °C and 60 °C. It shows that with increasing the temperature from −5 °C to 60 °C, the specific capacity increases, while the cycling stability becomes worse. The operation temperature has a pronounced influence on the pseudocapacitive performance of Co3O4 nanoflake array. [ABSTRACT FROM AUTHOR]