Microstructural investigation and electrochemical property of Mg63Ni27Nd10 amorphous alloy

Amorphous Mg-based alloy Mg63Ni27Nd10 was prepared by melt-spinning. The phase structures and the electrochemical properties of the ribbons before and after charge/discharge cycling were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) analysis and galvanotactic charge-discharge cycle test, respectively. It was found that the amorphous structure begins to crystallize after four cycles of hydrogenation/dehydrogenation and a new nano-crystallized phase NdMg2Ni9 was detected with average grain size in the range 5-10nm. A good cycle life and high discharge capacity were also observed in the Mg63Ni27Nd10 alloy electrode. The highest discharge capacity reached 580.5 mAh g(-1) at the discharge current densities of 50 mA g(-1). It is suggested that homogeneous microstructure contributes to the enhancement in electrochemical characteristics, the presence of NdMg2Ni9 being beneficial for the improvement in cycle life of Mg63Ni27Nd10 alloy electrode. (c) 2008 Elsevier B.V. All rights reserved.