Synergistic effects of Ce and Ni on hydrogen storage properties in Mg-based alloys

To address the kinetic limitations of Mg-based hydrogen storage materials, the synergistic effects of Ce and Ni on hydrogen storage kinetics of Mg-based alloys were investigated. Microstructural evolution studies reveal that the as-cast 18R-type long-period ordered stacking phase (LPSO) phase decomposes into MgH₂ and CeH_2.73 phases, with an average particle size of approximately 50 nm after initial hydrogen absorption. The Mg-10Ni-10Ce alloy demonstrates exceptional hydrogen storage kinetics. At 300 °C and 40 bar H₂, Mg-10Ni-10Ce particles with a size range of 200–400 μm can dehydrogenate up to 6.4 wt% within 10 min and rehydrogenate up to 5.9 wt% within 1 h. This performance significantly surpasses that of Mg-8Ni control samples with same particle size. Analysis reveals that the addition of Ni significantly enhances dehydrogenation kinetics, while CeH_2.73 particles accelerate H₂ dissociation and serve as nucleation sites for the MgH₂ phase. This synergistic effect markedly improves the hydrogen storage kinetics of the Mg-Ni-Ce alloy.