Magnesium-based alloys are promising hydrogen storage materials because of their high storage capacity and low cost. It was found that the electrochemical activity of nanocrystalline hydrogen storage alloys can be improved in many ways, by alloying with other elements, by ball-milling the alloy powders with a small amount of nickel or graphite powders. The surface modification of nanocrystalline hydrogen storage alloys with graphite by ball-milling leads to an improvement in both discharge capacity and charge-discharge cycle. In this work, an amorphous 2Mg+ 3d/x wt% Ni materials were prepared by mechanical alloying (MA) of Mg and 3d elemental powders (3d = Fe, Ni  x=0, 100 and 200%) under high purity argon atmosphere in SPEX 8000 Mixer Mill. The effect of the Ni addition on the electrochemical properties of the synthesized nanostructured alloys was investigated in details. The discharge capacity of amorphous 2Mg+Fe (Ni) high energy ball milled with Ni was improved. With increasing nickel content in the studied 2Mg+Fe (Ni) materials, at first cycle, the discharge capacity increases first and then decreases, and for x = 100 in 2Mg+Fe reaches a maximum value of 155 mAh g⁻¹. The elemental nickel was distributed inside of mechanically alloyed Mg-Fe (Ni) particles homogenously. It is generally agreed that the role of nickel particles is to catalyze the electrochemical reaction and/or reduce the diffusion resistance of hydrogen. Additionally, when coated with palladium, the discharge capacity of an amorphous 2Mg+Fe (Ni) powders was increased. The elemental palladium was distributed on the surface of ball milled alloy particles homogenously and role of these particles is to catalyse the dissociation of molecular hydrogen on the surface of studied alloy.  Mechanical coating with palladium effectively reduced the degradation rate of the studied electrode materials. Compared to that of the uncoated powders, the degradation of the coated was suppressed. The amorphous Mg-based hydrides offer a breakthrough in prospects for practical applications.

This work was supported by the Polish National Committee for Scientific Research under the contract No PBZ-KBN-117/T08/07 and also financial supported of UE project “Human Capital” by the Provincial Work Office in Poznan

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/18778 must be provided.

1. Hydriding properties of Mg-3d/M type nanocomposites (3d=Cu, Ni; M=C, Ni, Cu, Pd)