Effects of Zr addition on electrochemical characteristics of MgTiMnNi hydrogen storage alloys

The electrochemical hydrogen storage properties of 25 h milled Mg0.80Ti0.175Mn0.025ZrxNi1-x (x = 0, 0.025, 0.05, 0.1) quinary alloys were investigated. The substitution of Zr for Mg or Ni leads to an increase in structural disorder and amorphization. Thus, the maximum discharge capacity and the cycling stability of MgNi-based alloys can be enhanced. The x-ray diffraction patterns indicate that all additive elements are entirely dissolved in the synthesized alloys, and amorphous structure was successfully obtained by 25 h milling. Among the milled alloys, the Mg0.80Ti0.175Mn0.025Zr0.10Ni0.90 alloy exhibited the best discharge capacity of 604 mA h g−1 at the initial charge/discharge cycle. The obtained results demonstrate that using multi-component compositions is beneficial for enhancing the structural and cyclic stability of MgNi-based alloys. Therefore, substituting additive elements for Mg or Ni may offer impressive performance for efficient hydrogen storage applications.