Effects of microstructure on the electrode properties of melt-spun Mg-based amorphous alloys

Amorphous and nanocrystalline Mg-based alloys (Mg60Ni25)100−xNdx (x = 2, 5, 10, 15) were prepared by rapid solidification. 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. The experimental results showed that the discharge capacities increased with increasing Nd atomic content and the optimum Nd content is between 10 and 15 mol%. The highest discharge capacity reached more than 580 mAh/g at the discharge current densities of 50 mA/g for (Mg60Ni25)90Nd10 samples. However, the discharge capacity gradually becomes low with the crystallization proceeding of amorphous structure. It was suggested that the amorphous structure was a key factor to achieve high discharge capacity and good cycling stability.