Hydrogen storage in magnesium-based composites has been an outstanding research area including a remarkable improvement of the H-sorption properties of this system in the last 5 years. Numerous additives of various morphologies have been applied with great success to accelerate the absorption/desorption reactions. Different combinations of catalysts and preparation conditions have also been explored to synthesize better hydrogen storing materials. At the same time, ball milling is still commonly and effectively applied for the fabrication of Mg-based alloys and composites in order to reduce the grain size to nanometric dimensions and to disperse the catalyst particles over the surface of the host material. In this review, we present the very recent progress, from 2016 to 2021, on catalyzing the hydrogen sorption of Mg-based materials by ball milling. The various catalyzing routes enhancing the hydrogenation performance, including in situ formation of catalysts and synergistic improvement achieved by using multiple additives, will also be summarized. At the end of this work, some thoughts on the prospects for future research will be highlighted.

As the most abundant element in the world, hydrogen is a promising energy carrier and has received continuously growing attention in the last couple of decades. At the very moment, hydrogen fuel is imagined as the part of a sustainable and eco-friendly energy system, the “hydrogen grand challenge”. Among the large number of storage solutions, solid-state hydrogen storage is considered to be the safest and most efficient route for on-board applications via fuel cell devices. Notwithstanding the various advantages, storing hydrogen in a lightweight and compact form still presents a barrier towards the wide-spread commercialization of hydrogen technology. In this review paper we summarize the latest findings on solid-state storage solutions of different non-equilibrium systems which have been synthesized by mechanical routes based on severe plastic deformation. Among these deformation techniques, high-pressure torsion is proved to be a proficient method due to the extremely high applied shear strain that develops in bulk nanocrystalline and amorphous materials.