Research demonstrates that indium dissolution in magnesium enhances hydrogenation/dehydrogenation properties of magnesium; however, the underlying mechanism requires further elucidation. First-principles molecular dynamics simulations reveal that the incorporation of In restructures the charge distribution on the Mg surface, promoting interfacial reaction activity and thereby enhancing hydrogenation/dehydrogenation kinetics. During the hydrogenation process, metastable intermetallic phases Mg2In and Mg3In form alongside MgH2. Upon subsequent dehydrogenation, these intermetallic phases decompose, allowing In atoms to diffuse into the Mg matrix and form the Mg(In) solid solution. Notably, hydrogen diffusion coefficients in MgH2–In are 3-fold higher than in MgH2. In incorporation markedly enhances hydrogenation/dehydrogenation kinetics for Mg/MgH2, with MgH2–In exhibiting twice the dehydrogenation rate of MgH2. These theoretical predictions are validated by parallel experiments. Mg–4 wt %In alloys prepared by high-energy ball milling show enhanced dehydrogenation kinetics and reduced enthalpy changes. Microstructural analysis confirms the simulated phase evolution (Mg2In → Mg3In → Mg(In)) and reveals that In incorporation refines particle size, thus further improving cycling performance. This work establishes a theoretical foundation for developing Mg–In solid solution alloys as high-performance hydrogen storage materials.
Du et al. (Thu,) studied this question.