Effects of Co introduction on hydrogen storage properties of Ti–Fe–Mn alloys

• Introduction of Co can improve pulverization resistance of TiFeMn alloys.
• Co introduction in TiFeMn ternary alloys can flat β phase dehydrogenation plateau.
• The substitute of Co for Mn in TiFeMn alloys can enhance hydrogen storage capacity.
• TiFe0.86Mn0.05Co0.05 presents the highest hydrogen storage capacity close to 2 wt.%.
• TiFe0.86Mn0.04Co0.1 has a pretty flat β phase dehydrogenation plateau.

TiFe0.86Mn0.1−xCox (x = 0, 0.04, 0.05, 0.06) alloys were prepared by RF magnetic levitation melting. These alloys are determined as a single CsCl type phase. As x increases from 0 to 0.06, the unit cell volume decreases while the maximum hydrogen capacity rises to a threshold and starts to reduce thereafter. The particle size test shows that the pulverization resistance of the alloys improves significantly with the introduction of Co. After that, the effects of further increasing of Co content in this series of alloys were investigated. It is found that the appropriate proportion of Mn and Co leads to a fairly flat β phase dehydrogenation plateau. In addition, all the alloys could be easily activated. Among these alloys, TiFe0.86Mn0.05Co0.05 exhibits the highest hydrogen storage capacity of 1.98 wt.% at the temperature of 273 K, while TiFe0.86Mn0.04Co0.1 presents the best plateau property.