Tuning the hydrogen storage properties of MgH ₂ : advanced approaches with alloying, doping, perovskites, and nanostructured engineering

Magnesium hydride (MgH 2 ) is recognized as a promising solid-state hydrogen storage material due to its high theoretical hydrogen capacity (7.6 wt%), low cost, and abundance. However, its practical application is hindered by high thermodynamic stability, slow hydrogenation–dehydrogenation kinetics, and elevated operating temperatures. This review provides a comprehensive overview of recent advances in improving the hydrogen storage properties of MgH 2 through various modification strategies. Key approaches, including alloying with transition metals and high-entropy alloys, catalytic doping using metal oxides, phosphides, and carbon-supported materials (such as graphene or CNTs), and nanostructuring techniques, are systematically discussed. In addition, magnesium-based composites and complex hydrides such as Mg(BH 4 ) 2 and Mg(AlH 4 ) 2 are explored for their enhanced hydrogen storage capabilities under catalytic and nanoconfined conditions. Particular attention is given to emerging strategies involving perovskite additives and nanoscale single-atom catalysts, which significantly improve hydrogen sorption kinetics, reduce activation energy, and lower desorption temperatures, thereby enhancing the overall hydrogen storage performance of MgH 2 systems. The review highlights the synergistic effects of combining multiple modification techniques to overcome the intrinsic limitations of MgH 2 . Despite substantial progress, challenges remain in achieving efficient hydrogen storage at near-ambient conditions with long-term stability.