Materials for hydrogen storage

A. M. ROBINA; M. E. PRONSATO

Revista Argentina de Ingeniería

Publicación del Consejo Federal de Decanos de Ingeniería de la República Argentina

Lugar: CABA; Año: 2015 vol. 6 p. 41 - 47

2314-0925

In the present article two systemsstudied theoretically in the Physics Departmentof the Universidad Nacional del Sur arepresented. Both are related to the Physics of Materials,more specifically to intermetallic hydrogenstorage materials, and have been developed usingself-consistent Density Functional Theory (DFT)calculations. DFT is a phenomenally successfulapproach to finding solutions to the fundamentalexpression that describes the quantum behaviourof atoms and molecules, the Schrödinger equation,in settings of practical value.Laves phases, under the representative formscubic MgCu2 (C15) and hexagonal MgZn2 (C14)and MgNi2 (C36), have been extensively studieddue to their promising behavior as solid state hydrogenstorage materials, ease of synthesis by theconventional cast methods, flexibility in tailoringthe thermodynamic properties and good absorption/desorption kinetics and cycle life. However,they cannot be used for technological applicationsbecause of its too strong hydride stability at roomtemperature.In this work we studied the hydrogen absorptionfor Zr(Cr0.5Ni0.5)2, isostructural with theMgZn2 Laves phase, with the aim to find the mostenergetically favorable interstitial sites to locatehydrogen. Bulk modulus and volume cell changesdue to the hydrogenation process were also analyzedfor this phase.According to literature, the most stable werethe A2B2 sites, with an absorption energy averageof -0.25 eV, followed by the AB3 sites. Bulk Modulusfluctuated in the range of 150 and165 GPa.