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Abstract-We reported density functional studies of the structure and thermodynamics of NaMgH 3 in the cubic perovskite structure as well as corresponding fluorides. Analyses of the calculation results in terms of formation enthalpies, substitution enthalpies, reaction enthalpies showed that partial H were replaced with halogen in catalyst which improved thermodynamic properties, facilitate dehydrogenation of hydrides. The obtained calculation results suggested that halidedoped in NaMgH 3 may result in a favorable thermodynamics modification, and accordingly result in a favorable modification for onboard hydrogen storage application.

The chemical hydride NaMgH3 is considered to be a promising candidate for hydrogen storage materials with its high hydrogen gravimetric and volumetric densities. The mechanism of the improved dehydrogenating properties of NaMgH3 doped by F anion was investigated using plane-wave pseudopotential （PW-PP） approach based on the density functional theory （DFT）. Computational results show that the formation enthalpy and reaction enthalpy of the hydride decrease drastically with the substitution of F for H. This results in a favorable thermodynamic modification, and facilitates the dehydrogenation reaction of the hydrides.