Ti–V–Mn based metal hydrides for hydrogen storage

• Ti0.47V0.46Mn and Ti0.50V0.51Mn alloys were produced by arc melting.
• Compositional differences led to different unit cell volumes for the C14 Laves phase.
• Change in composition caused a significant change in plateau pressure and hysteresis.

Two Ti–V–Mn BCC-Laves phase alloys with the nominal composition Ti0.5V0.5±xMn (x = −0.04 and 0.01), were synthesised by arc melting. This compositional difference resulted in different compositions and unit cell volumes for the C14 Laves phase. Ti0.47V0.46Mn and Ti0.50V0.51Mn demonstrated reversible hydrogen sorption capacities of 1.53 and 1.56 ± 0.05 wt.% (at 120 bar H2 at 303 K) respectively, however, the change in composition results in a small change in the enthalpy of hydride decomposition, and a significant change in plateau pressure and hysteresis. This may allow for the plateau pressure to be tuned to meet the requirements of different solid-state hydrogen storage applications.