Hydrogen storage properties of Ti1.4V0.6Ni + x Mg (x = 1–3, wt.%) alloys

• Ti1.4V0.6Ni + Mg composite alloys were prepared by mechanical milling.
• The structures of composite alloys contain icosahedral quasicrystalline phase.
• Ti1.4V0.6Ni + Mg alloys show superior hydrogen storage properties.
• Hydrogen diffusion and anti-corrosion ability are improved by Mg addition.

We prepared Ti1.4V0.6Ni ribbons by arc-melting and subsequent melt-spinning techniques. Ti1.4V0.6Ni + x Mg (x = 1, 1.5, 2, 2.5 and 3, wt.%) composite alloys were obtained by the mechanical ball-milling method. The structures and hydrogen storage properties of alloys were investigated. Ti1.4V0.6Ni + x Mg composite alloys contained icosahedral quasicrystalline phase, Ti2Ni-type phase, β-Ti solid-solution phase and metallic Mg. The electrochemical and gaseous hydrogen storage properties of alloys were improved with Mg addition. Ti1.4V0.6Ni + 2 Mg alloy showed maximum electrochemical discharge capacity of 282.5 mAh g−1 as well as copacetic high-rate discharge ability of 82.3% at the discharge current density of 240 mA g−1 compared with that of 30 mA g−1, and the cycling life achieved above 200 mAh g−1 after 50 consecutive cycles of charging and discharging. The hydrogen absorption/desorption properties of Ti1.4V0.6Ni + x Mg (x = 1, 2 and 3, wt.%) alloys were better than Ti1.4V0.6Ni. Ti1.4V0.6Ni + 3 Mg alloy also exhibited a favorable hydrogen absorption capacity of 1.53 wt.%. The improvement in the hydrogen storage characteristics caused by adding Mg may be ascribed to better hydrogen diffusion and anti-corrosion ability.