Electrochemical Characteristics of Melt Spun Nanocrystalline and Amorphous Mg<sub>20</sub>Ni<sub>6</sub>M<sub>4</sub> (M=Co, Cu) Alloys Applied to Ni-MH Battery

The melt-spinning technique was used to synthesize the Mg 20 Ni 6 M 4 (M=Co, Cu) alloys with nanocrystalline and amorphous structure. The microstructures of the as-spun alloys were characterized by XRD and TEM. The electrochemical hydrogen storage properties of the alloys were measured. The results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg 2 Ni-type alloy. The discharge capacity and high rate discharge ability (HRD) of the alloys notably augment with the rising of the spinning rate. The action of the melt spinning on the cycle stability of the alloys is associated with the substitution element. For the (M=Co) alloy, the melt spinning exerts a dramatically positive impact, whereas for the (M=Cu) alloy, its impact is negative.