Experimental Study of Hydrogen Storage at Low-Pressure and Low Temperatures Using Metal Hydrides

In this chapter, an experimental investigation is carried out to study the characteristics of the pressure-composition isotherms (P-C-T) of the LaNi4Mn0.5Co0.5 alloy. These isotherms provided important information about the phase transitions, thermodynamic properties and stability of the alloy under different conditions. The effects of feed pressure and cooling, as well as heating temperature on the rate of hydrogen uptake/desorption by the alloy were analyzed. The effects of the partial substitution of Ni by the elements Mn and Co on the phase structure and hydrogen storage properties of LaNi4Mn0.5Co0.5 alloy are studied. It is known that the Mn, Co elements decrease the plateau pressure of hydrogen absorption and desorption of LaNi4Mn0.5Co0.5 alloy. For that, the substitution of these elements improve kinetic velocity of hydrogen storage capacity. The LaNi4Mn0.5Co0.5 alloy also shows excellent plateau performance with very small hysteresis and sloping which is attributed to the interstitial size effect.