Enhancement of the hydrogen storage properties and sorption kinetics of Mg-La28.9Ni67.5Si3.6 nanocomposites

The challenges of elevated ab/desorption temperatures and sluggish sorption kinetics continue to pose obstacles for the potential use of Mg/MgH2-based hydrides as hydrogen storage materials in automobile applications. LaNiSi alloy is a superior catalyst for molecular hydrogen dissociation. So, to improve the hydrogen sorption kinetics as well ab/desorption capacity of magnesium, here in this report we added La28.9Ni67.5Si3.6 alloy as a catalyst. The alloy of La28.9Ni67.5Si3.6 was synthesized by an Arc melting furnace into an inert environment. Study of surface morphology and crystal structure of synthesized nanocomposites has been done by a HRTEM and XRD analysis. XRD confirm the presence of various phases in the composites, which is possibly during ball milling and de/rehydrogenation reaction. The PCT analysis demonstrates that the introduction of La28.9Ni67.5Si3.6 nanocomposites leads to enhancements in both the hydrogen storage capacity and sorption kinetics of Mg/MgH2. Specifically, Mg with a 5 wt% addition of La28.9Ni67.5Si3.6 nanocomposites exhibits the highest hydrogen storage capacity, measuring approximately 6.44 wt%, nearly twice that of pure Mg subjected to 50 h of milling. DSC analysis provides corroborating evidence, revealing that as the concentration of La28.9Ni67.5Si3.6 increases, the dehydrogenation temperature of Mg/MgH2 decreases. Furthermore, the addition of La28.9Ni67.5Si3.6 composites leads to a reduction in the activation energy of the dehydrogenation reaction of MgH2, decreasing it from 191.27 to 77.89 -kJ/mol.