Effects of Cu and Y substitution on hydrogen storage performance of TiFe0.86Mn0.1Y0.1−xCux

The aim of this study is to investigate systematically the remarkably improved hydrogen storage capacity and faster activation performance of TiFe0.86Mn0.1Y0.1−xCux where x = 0.01, 0.03, 0.05, 0.07, 0.09 alloys. The designed alloys were synthesized via water-cooled copper crucible and the phase analysis, morphology study and elemental analysis of as-synthesized alloys were investigated. Afterwards, the hydrogen storage performance and kinetic test of alloys powder were employed. The results show that the hydrogen storage capacity increases first and then decreases slightly with increase of Y additives, whereas the absorption/desorption plateau pressure and slop decreases, and the highest hydrogen capacity of TiFe0.86Mn0.1Y0.05Cu0.05 is achieved 1.89 wt% at 10 °C. The element Cu causes deterioration in hydrogen capacity but improves activation, and the capacity decreases with increase of Cu content. Furthermore, the activation and kinetics rate of each alloy is improved with secondary phase particles (CuY and Cu4Y) observed in scanning electron microscope/energy dispersive spectroscopy (SEM/EDS), and the TiFe0.86Mn0.1Y0.05Cu0.05 alloy shows fastest kinetic rate at 10 °C, this may ascribe to the secondary phase which provides new channels for hydrogen flux to penetrate into the matrix. The interfaces between the matrix and secondary phase particles are very active for hydrogen absorption and improve hydrogen absorption performance remarkably.