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Hydrided Mg-3Ni-2MnO₂ composite powders were prepared by mechanical milling under hydrogen atmosphere. Heat and mass transfer, the effective thermal conductivity (ETC) of the hydrided Mg-3Ni-2MnO₂ powder reaction bed with various porosities were measured using a self-made apparatus. The effect of porosity on the bed is also analysized. The results show that the ETC of reaction bed is poor and it increases with decreasing porosity. Three porosities, 0.37, 0.53, 0.63 were selected in the present work. The bed with 0.53 porosity exhibits relatively fast reaction rates in both hydrogenation and dehydrogenation process. The hydrogenation process is a fast exothermic reaction resulting in a quick increase if the temperature of the bed during this process, and there is a temperature gradient: the temperature close to the bed wall is lower but higher at the center of bed. In dehydrogenation of the bed, the temperature of hydrided bed decreases due to the endothermic reaction, and the temperature at the center falls the lowest and keep at that temperature for a long time. The analyses reveal that increase of ETC don't always helps to improve the bed's hydriding and dehydriding rates. There should be an optimal porosity which helps to transfer both the heat and the mass.

Optimized geometry structures, total energies, infrared spectra, thermodynamics parameters of lanthanide hydrides and the reaction between lanthanide atom and hydrogen atom are studied use effective core potentials. Results indicate that lanthanide contract phenomenon are effected the bond lengths of lanthanide hydride. Most of lanthanide hydride will release heat (except for monohydrides of Tm and Yb) in the reaction. All of the calculated vibrating frequencies of lanthanide hydrides are positive. Most of the trihydride are stable than dihydride except for Yb. Bond orbits in lanthanide hydrides are mainly contributed by s and d compounds, there are much more f compound in lanthanide trihydride molecular.

The hydrogen storage property of Cl-doped LiNH₂ has been investigated by using first-principles method based on density functional theory. The calculated results show that Cl doping may result in the substitution of ${\text{NH}}_2^{-}$ by Cl⁻ in the hydride lattice and accordingly, a favorable thermodynamics modification. The electron structure analysis shows that Cl doping induces the movement of Li-2s towards higher energy levels and weakens the interaction between Li and N. The increased interaction between Cl and Li benefit the early release of NH₃. The hydrogen desorption property is thus improved.