Studies on the hydrogen absorption properties of LaNi5−xSnx and La0.95Ni4.6Sn0.3 alloys using magnetic and thermoelectric power measurement

Magnetic and thermoelectric power (TEP) measurements are used to quantify hydrogen availability, absorption, and desorption in materials for nickel-hydride batteries and hydrogen storage. The effect of the concentration of conduction electrons is introduced and used to investigate hydride properties of these alloys. To investigate hydrogenation properties the calculated average number ofd-band electrons in hydrogen storage material is related to the measured thermoelectric power. Also, a thermodynamic exprssion of equilibrium is applied to demonstrate the relationship between the TEP and the activity of hydrogen for hydrogen adsorption. Magnetization decreases with increasing absorbed hydrogen in the stoichiometric LaNi_4.78Sn_0.22 alloy. However, magnetization increases with increasing hydrogen content in the nonstoichiometric La_0.95Ni_4.6Sn_0.3 alloy. The TEP for the stoichiometric LaNi_4.78Sn_0.22 alloy monotonically increases as a function of hydrogen content. However, the TEP of the nonstoichiometric La_0.95Ni_4.6Sn_0.3 alloy decreases as hydrogen content increases.