Effect of Mn, Ti/Cr ratio, and heat treatment on hydrogen storage properties of TI-V-CR-MN alloys

This study elucidates the effects of adding Mn, the Ti/Cr ratio, and high-temperature annealing on the hydrogen absorption-desorption properties of Ti-V-Cr-Mn body-centered cubic alloys. The hydrogen storage properties of alloys are also modified by integrating the positive effects. X-ray diffraction analysis indicates that the lattice parameters decrease linearly with an increasing Mn content. Additionally, the reversible hydrogen desorption capacity is increased as the Mn content is increased from 0 at.% to 15 at.%, without apparently degrading hydrogen absorption capacities. Despite increasing the desorption pressure, the decrease of Ti/Cr ratio slightly reduces the absorption and desorption capacities. The Ti₃₃V₃₃Cr ₁₉Mn₁₅ alloy has a reversible hydrogen desorption capacity as high as 2.48 mass% at 80°C. Moreover, the as-heat-treated (1200°C, 10 h) Ti₃₁V₃₃Cr₂₁Mn₁₅ alloy has a flatter plateau pressure and a higher amount of desorption pressure (greater than 1 atm) than those of the as-cast alloy.