Electrochemical hydrogen storage characteristics of nanocrystalline Mg20Ni10−x Cu x (x =0–4) alloys prepared by melt-spinning

Abstract: In order to improve the electrochemical hydrogen storage characteristics of the Mg2Ni-type alloys, Ni in the alloy was partially substituted by element Cu, and the nanocrystalline Mg2Ni-type Mg20Ni10−x Cu x (x =0–4) alloys were synthesized by melt-spinning technique. The structures of the as-cast and spun alloys were studied by XRD, SEM and HRTEM. The electrochemical hydrogen storage performances were tested by an automatic galvanostatic system. The results show that the substitution of Cu for Ni does not change the major phase Mg2Ni, but it leads to a significant refinement of the grains of the as-cast alloys. All the as-spun alloys hold nanocrystalline structures and are free of amorphous phase. The discharge capacity of the alloys first increases and then decreases with rising amount of Cu substitution, whereas the electrochemical cycle stability of the alloys monotonously grows with increasing Cu content. [Copyright &y& Elsevier]