The structures and electrochemical properties of the Ti1.4V0.6Ni ribbon before and after heat treatment are investigated systematically. The structure of the sample is characterized by X-ray powder diffraction analysis. Electrochemical properties including the discharge capacity, the cyclic stability and the high-rate discharge ability are tested. X-ray powder diffraction analysis shows that after heat treatment at 590 °C for 30 min, all samples mainly consist of the icosahedral quasicrystal phase (I-phase), Ti2Ni phase (FCC), V-based solid solution phase (BCC) and C14 Laves phase (hexagonal). Electrochemical measurements show that the maximum discharge capacity of the alloy electrode after heat treatment is 330.9 mA?h/g under the conditions that the discharge current density is 30 mA/g and the temperature is 30 °C. The result indicates that the cyclic stability and the high-rate discharge ability are all improved. In addition, the electrochemical kinetics of the alloy electrode is also studied by electrochemical impedance spectroscopy (EIS) and hydrogen diffusion coefficient (D).
The Ti0.9Zr0.1V0.2Ni1.5La0.5 alloy samples were synthesized by melt-spinning technique at the different wheel velocity （cooling rate）, and the structure and electrochenfical hydrogen storage properties were investigated. The result indicated that the structure of the melt-spun ribbons mainly contains C14 Laves phase and V-based solid solution phase. The discharge capacity, cyclic stability, high-rate discharge ability and electrochemical kinetic of the alloy electrodes are correlated with the cooling rate （wheel velocity）, and the maximum discharge capacity is over 200 mA.h/g at the wheel velocity of 20 m/s.
Jian WANGGuang-bo CHEQing-wei WANGWan-xi ZHANGLi-min WANG
A novel mixed-valent heterometallic pentanuclear CoⅢ3 CoⅡ Dy Ⅲ cluster has been rationally assembled taking advantage of a bifunctional ligand with o-vanillin and tripodal tris(hydroxymethyl)aminomethane units. This unique heterometallic cluster represents a rare example of T-shaped molecules exhibiting slow magnetic relaxation.
Mg?1Zn?0.5Ca alloys were prepared by traditional steel mould casting and water-cooled copper mould injection casting at higher cooling rate. Microstructure, mechanical properties and bio-corrosion resistance of two alloys were contrastively investigated. Grain size reduces remarkably and microstructure becomes homogenous when raising cooling rate. The bio-corrosion behaviour in 3.5% sodium chloride solution (3.5% NaCl) and Hank’s solution at 37°C was investigated using electrochemical polarization measurement and the results indicate that the alloy prepared at higher cooling rates has better corrosion resistance in both types of solution. Further mass loss immersion test in Hank’s solution reveals the same result. The reason of corrosion resistance improvement is that raising cooling rate brings about homogeneous microstructure, which leads to micro-galvanic corrosion alleviation. The tensile test results show that yield strength, ultimate tensile strength and elongation are improved by raising cooling rate and the improvement is mainly due to grain refinement.
Supercapacitors（SCs） have attracted much attention as one of the alternative energy devices due to their high power performance,long cycle life,and low maintenance cost.Graphene is considered as an innovative and promising material due to its large theoretical specific surface area,high electrical conductivity,good mechanical properties and chemical stability.Herein,we report an effective strategy for elaborately constructing rationally functionalized self-standing graphene（SG） obtained from giant graphene oxide（GGO） paper followed by an ultrarapid thermal-processing.This treatment results in both the exfoliation of graphene sheets and the reduction of GGO by elimination of oxygencontaining groups.The as-prepared SG electrode materials without additive and conducting agent provide an excellent combination of the electrical double layer capacitor（EDLC） and pseudocapacitor（PC） functions and exhibit superior electrochemical performance,including high specific capacitance,good rate capability and excellent cycling stability when investigated in three-electrode electrochemical cells.
The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the as-cast alloy and restrain grain growth during solution treatment, which was derived from the constitutional supercooling during solidification process and the formation of stable intermetallic compounds Ce Mg12 and Mg17La2. Furthermore, Ce/La microalloying and solution treatment resulted in an evolution from the original lamellar Ca2Mg6Zn3/α-Mg to the divorced eutectic structure. The thermal stability of Mg-Zn-Ca alloy could be effectively improved by Ce/La addition, because the low-melting-point binary Mg-Zn phase was transformed to Mg x Zn y-Ca-（Ce/La） phase with higher thermal stability and the amount of Ca2Mg6Zn3/α-Mg eutectic structure was reduced.
