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The Co–B alloy was prepared by the chemical reduction method and the annealing method. The structural and morphological characterizations were performed using TEM and XRD. The Electrochemical Measurements were performed using LAND battery test instrument. After annealing treatment,the initial Co–B alloy decomposes to crystalline Co and B with a kind of coating sphere structure. The excellent electrochemical hydrogen storage properties are also obtained. Keywords: Coating sphere structure, Co–B alloy, Annealing treatment, Hydrogen storage

The alloys Co2B were prepared by two ways of high temperature solid phase process and arc melting, the structure of the alloys was characterized by XRD and SEM. It showed that it was structure of tetragonal Co2B.The electrochemical experimental results demonstrated that the Co2B prepared by two means both showed excellent cycling stability. The initial discharge capacity of Co2B prepared by the high temperature solid phase process was 480.3 mA h g−1, there was no distinct declination after 70 charge–discharge cycles and the capacity kept about 195 mA h g−1. Co2B prepared by the high temperature solid phase process showed very good electrochemical reversibility in CV curves. The hydrogen storage mechanism was also discussed, it confirmed that the high initial capacity of Co2B prepared by the high temperature solid phase process was due to the oxidation of Co and B2O3, and it was irreversible. Keywords: Co2B alloy, Hydrogen storage, High temperature solid phase process, Arc melting, Negative electrode

The electronic conductivity of Cu0.1-doped VOx-NTs is up to magnitude higher than that of the undoped material. Doped vanadium oxide nanotubes also exhibit significantly improved kinetic behavior and rate capability. Cu0.1-doped VOx-NTs present good electrochemical behaviors at 10 mA/g discharge current density with initial specific capacity 120.2 mAh/g. Keywords: Rechargeable magnesium battery, Doped vanadium oxide nanotubes, Electrochemical intercalation

Vanadium oxide nanotubes (VOx-NTs) were obtained as the main product in a sol–gel reaction followed by hydrothermal treatment from V2O5 precursors and primary amines. The material has a considerable large distance between the layers (ca. 3.5 nm), a wide inner (15–40 nm) and outer diameter (60–100 nm), and the open tube ends which are favorable for the magnesium ion insertion. VOx-NTs are a new kind of material with a unique nanostructured morphology, which can electrochemically insert/deinsert magnesium ions reversibly from the cyclic voltammogram. AC impedance (EIS) demonstrated that Mg2+ diffusion into the nanotubes is faster than polycrystalline V2O5 during intercalation Mg2+ into the cathodes. X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRD) results gave the mechanism of Mg2+ insertion into the nanotubes, however, the specific capacity of the rechargeable magnesium is lower than that of lithium. Keywords: Rechargeable magnesium battery, Magnesium intercalation, Vanadium oxide nanotubes