Effective enhancement of hydrogen storage kinetics and cyclic stability of MgH2 via NiCo alloy

Magnesium hydride (MgH 2 ) is a promising hydrogen storage material for high hydrogen density, but its application is hindered by sluggish kinetics. Herein, a NiCo alloy was synthesized via hydrothermal treatment followed by calcination to enhance the hydrogen storage performance of MgH 2 . The MgH 2 +7 wt% NiCo system exhibits a starting desorption temperature of 211 °C and a dehydrogenation activation energy of 82.47 kJ/mol, and the dehydrogenated product absorbs 5.49 wt% H 2 in 1 min at 120 °C. Moreover, this system shows a 6.9 wt% hydrogen with 95.2% retention after 20 cycles, exhibiting exceptional cycling stability. The enhanced hydrogen storage performance of MgH 2 stems from the synergistic effects of structural regulation and electronic modulation. In-situ formed Mg 2 Ni/Mg 2 NiH 4 acts as a “hydrogen pump” to provide hydrogen transport pathways, while electronic interactions between Ni and Co facilitate H 2 dissociation and diffusion. This research offers valuable perspectives for designing transition metal-based additives for solid-state hydrogen storage.