First-principle calculation for a novel hydrogen storage material Mg₂Ni and its substitutes

A novel hydrogen storage material Mg₂Ni has been studied by the first-principle methods based on plane-wave pseudopotential theory. The corresponding electronic structure of hydrogen storage materials, Mg₂Ni, Mg₁₂Ni₅M₁ (M = Mn and Cu), and their hydride have also been investigated. The enthalpy of hydrogenation reaction is -65.07kJ/mol (H₂), which is in line with the experimental results. The stability of the new hydride alloy increased by substitution with Cu, and a small amount of alternative might be preventing powdering after several cycles. The Mn atom substitutes Ni atom of hydride alloy which would weaken the H-Ni bond, and the temperature of desorption decreased. The results will play an important role in practical application.