Galvanostatic, cyclic voltammetric and evolved gas analysis studies have been carried out on Mm Ni4.5 Al0.5 and CaNi5 alloys. Galvanostatic studies show ed that both Mm Ni4.5 Al0.5 and CaNi5 alloys show high storage capacity and they follow activation followed by degradation mechanism. Cyclic voltammetric studies showed that though the surface electron transfer reaction is the same, each hydride phase formation takes place at its own characteristic potentials. The fresh surface created during electrochemical cyclings show high electrocatalytic activity. Hydrogen evolution observed in EGA at room temperature is attributed to MmNi4.5 Al0.5 Hβ and CaNi5 Hδ}. Hydrogen evolution observed at high temperature from electrochernically charged alloys is attributed to the decomposition of MmNi4.5 Al0.5 Hα and CaNi5 Hβ mainly.