Enhanced Electrochemical Hydrogen Storage Characteristics of Mg₂Ni-Type Alloy by Substituting Mg with La

Abstract:

The melt-spinning technique is applied to the preparation of the nanocrystalline and amorphous Mg₂Ni-type alloys with nominal compositions of Mg_2-xLa_xNi (x=0, 0.2, 0.4, 0.6). The as-spun alloy ribbons possessing a continuous length, a thickness of about 30 μm and a width of about 25 mm were prepared. The structures of the as-spun alloy ribbons are characterized by XRD, SEM and TEM. The electrochemical performances of the as-spun alloy ribbons are measured by an automatic galvanostatic system. The results show that no amorphous structure is detected in the as-spun Mg₂Ni alloy, whereas the as-spun alloys substituted by La display a nanocrystalline and amorphous structure, confirming that the substitution of La for Mg notably intensifies the amorphous forming ability of the Mg₂Ni-type alloy. For La content x≤0.2, the substitution of La for Mg brings to the formation of LaMg₃ and La₂Mg₁₇ phases without changing the Mg2Ni major phase. But as La content is increased to x≥0.4, such substitution changes the major phase of the alloys to (La, Mg)Ni₃+LaMg₃. The discharge capacity of the as-cast alloys grows with the increasing amount of La substitution, whereas that of the as-spun alloys yields a maximum value with variation of La content. Furthermore, the substitution of La for Mg remarkably enhances the cycle stability of the as-cast and spun alloys. And the high rate dischargeability (HRD) of the as-cast and spun alloys first mounts up then falls with rising La content.

• Periodical: Advanced Materials Research (Volumes 399-401)
• Pages: 1461-1466
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.399-401.1461
• Online since: November 2011
• Authors: Hui Ping Ren, Bao Wei Li, Yin Zhang, Zai Guang Pang, Zhong Hui Hou, Yang Huan Zhang
• Keywords: Electrochemical Hydrogen Storage, Melt-Spinning, Mg₂Ni-Type Alloy, Substituting Mg with La

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