Advanced interpretation of hydrogen absorption process in LaMgNi3.6M0.4 (M = Ni,Mn, Al,Co, Cu) alloys using statistical physics treatment

To obtain good economic and environmental benefits, LaMgNi_3.6M_0.4 (M = Al, Mn, Ni, Co, Cu) alloys are investigated for the hydrogen storage. The absorption data of hydrogen in the tested alloys are measured experimentally at 373 K. The hydrogen absorption isotherms are analyzed using three models derived from statistical physics formalism. The adequate model permits to discover significant details about the absorption phenomenon via determining the density of the interstitial sites (D_m), the number of hydrogen atoms per site (n) and the energetic parameter ΔE. The results indicate that multi-atomic (n > 1) and multi-linking (n < 1) phenomena are feasible for hydrogen absorption in LaMgNi_3.6M_0.4 (M = Al, Mn, Ni, Cu, Co) metals. The effects of the substitutions of Ni with Mn, Co, Cu and Al on the hydrogen absorption capacity are investigated. The interaction hydrogen/metal is analyzed by the calculation of the absorption energies. The chemical interaction is the responsible for the hydrogen absorption phenomenon. The contribution of this work is to provide advanced investigations of the hydrogen absorption mechanism in LaMgNi_3.6M_0.4 (M = Al, Mn, Ni, Co, Cu) metals, which are promising alloys for the hydrogen storage.