Abstract: A nickel-doped Mg nanocrystals encapsulated by molecular-sieving reduced graphene oxide (rGO) layers is disclosed. Dual-channel doping, which combines external (rGO strain) and internal (Ni doping) mechanisms, efficiently promotes both hydriding and dehydriding processes of Mg nanocrystals, simultaneously improving both the kinetic and thermodynamic properties of the material. The composite achieves both high hydrogen storage capacity and excellent kinetics while maintaining robustness. The realization of three complementary functional components in one material-environmentally friendly and earth-abundant Mg for storage, Ni dopants for catalysis, and rGO layers for encapsulation-breaks new ground in metal hydrides and makes solid-state materials viable candidates for hydrogen-fueled applications.