Improved hydrogen storage in magnesium thin flakes via nickel and titanium/titanium carbide additives

Magnesium, as a promising material for solid-state hydrogen storage is limited for practical applications due to its sluggish kinetics, high desorption temperatures and the inability to reach its theoretical capacity of 7.7 wt% without extensive modifications or complex synthesis methods. In this study, Mg thin flakes produced by high energy ball milling of commercially pure Mg, were decorated with carbon-coated Ni nanoparticles and Ti/TiC composite particles through a dispersion process without milling media, ensuring a uniform distribution of catalysts without altering the flake-like morphology. The formation of Mg₂NiH₄ during the activation process played a key role in enhancing hydrogenation and dehydrogenation reactions, further amplified by the synergistic catalytic effect of Ti/TiC composite particles through spillover and hydrogen pump mechanisms. The optimized Mg–5 %Ni+0.5 %Ti/TiC composite achieved a hydrogen absorption capacity of 6.29 wt% in just 6 min at 300 °C/10 bar, while complete desorption occurred in 9 min at 350 °C; significantly improving upon pure Mg. Moreover, the material exhibited excellent cycling stability, maintaining full capacity over 15 cycles and even showing an increased capacity of 6.5 wt% after 30 cycles due to flake fragmentation induced by volumetric expansion-contraction effects. These results highlight the potential of Mg thin flakes as an intermediate material in a top-down approach for synthesizing fine Mg particles and composites with enhanced hydrogen storage performance.