Lattice dynamical investigation of hydrogen energy storage in metallic alloys

Hydrogen is the promising medium for both energy transmission and storage. Hydrogen can be stored safely inside certain metals and alloys. Attempts have been made for selecting good energy storage media. In the present work, the diffusion of hydrogen and deuterium in the bcc, substitutional alloy Cr_0.7Fe_0.3 and fcc substitutional alloy Ni_0.5Fe_0.5 have been reported in which Born-von Karman formalism with average atomic mass is used to compute the phonon dispersion. When H/2H is pumped into this alloy, it migrates through the host lattices by thermally activated jump to neighbouring empty interstitial sites. Mean Square Displacements (MSD) with hydrogen and deuterium interstitials are calculated for the temperature range 500 K-1250 K with normal to 2.5 GPa pressure by applying Green's function technique and scattering matrix formalism, The diffusion parameters are calculated using reaction coordinate technique in which the diffusivity is characterized by the diffusion constant which determines the storage capacity of the given systems of study. (author)