Hydrogenation properties of (V 0.85 Fe 0.15 ) 100− x M x –Ce BCC solid solution alloys with M = Cr, Mo, Al

The structure and hydrogenation properties of (V 0.85 Fe 0.15 ) 100− x M x –Ce ( x = 0, 1, 3, 5; at%) alloys with M = Cr, Mo, Al were investigated. All the alloys show the same phase composition consisting of BCC matric and CeO 2 phases which distribute along the grain boundary. The hydrogen capacities of (V 0.85 Fe 0.15 ) 100− x M x –Ce change little with M, and none of them exceeds 2.0 wt%. But the plateau pressure shows remarkable linearly variation with the amount of M and the lattice parameter of BCC matric. The additions of Cr, Mo and Al raise the plateau, but the linear relation of plateau versus BCC lattice parameter of Mo/Al‐added alloys is opposite to that of Cr‐added alloys and many other conventional hydrogen storage alloys. The radius of hydrogen site is introduced to explain the inconsistent. The plateau pressure of (V 0.85 Fe 0.15 ) 100− x M x –Ce with any kind of M added increases with the contraction of the hydrogen site. The plateau pressure of (V 0.85 Fe 0.15 ) 100− x M x –Ce can also be reflected by the stability of hydride which is judged by the enthalpy change during the dehydrogenation.