Mechanical alloying fabrication of nickel/cerium/MgH2 nanocomposite for hydrogen storage: Molecular dynamics study and experimental verification

Abstract

This study employed mechanical alloying (MA) to synthesize magnesium-based nanocomposites for hydrogen storage. To fabricate the composite materials, firstly, the vacuum arc re-melting (VAR) method was used to make cerium–nickel (Ce-Ni) alloy with two compositions, including 50Ce-50Ni (wt%) (CN1) and 25Ce-75Ni (wt%) (CN2). Then, 10 wt% of these alloys was milled with magnesium hydride (MgH2) for 5 and 15 h. The impact of milling time on the hydrogen desorption features of the prepared nanocomposites was estimated by the thermal analyzer method and compared to pure MgH2. The molecular dynamics (MD) method was employed to describe the enthalpy change of the nanocomposites mentioned above and pure MgH2 at the atomic scale. Experimental enthalpy results calculated by measuring the peak area in DSC curves also confirmed the molecular dynamics data. Since the enthalpy values of the manufactured nanocomposites were significantly lower than pure MgH2 (−75 kJ/mol), the lower desorption temperature in these specimens was justified.