Structures and hydrogen storage properties of AeVH3 (Ae = Be, Mg, Ca, Sr) perovskite hydrides by DFT calculations

Abstract

The capability of hydrogen to be an energy source has made the hydrogen storage as one of the most investigated research fields during the recent years, and novel perovskite materials have become the current focus for hydrogen storage applications. Here we study the AeVH3 (Ae = Be, Mg, Ca, Sr) perovskite-type hydrides to explorer their potential for hydrogen storage applications using the density functional theory (DFT) implemented CASTEP code along with exchange correlation potential. The study examines the electronic structure, optical properties, elastic features and mechanical stability of the materials. The crystal structure of AeVH3 compounds is found to be cubic with lattice constant as 3.66, 3.48, 3.76 and 3.83 for Ae = Be, Mg, Ca and Sr compounds, respectively. The calculated electronic structures of these compounds show ionic bonding and no energy bandgap. The mechanical characteristics of compounds are also investigated as to meet the Born stability criterion, these compounds should be mechanically stable. The Cauchy pressure and Pugh criteria revealed that these materials have a brittle character and rather hard. In low energy range, all optical properties are found to be suitable as needed for storing the hydrogen. Furthermore, the gravimetric ratios suggested that all the compounds are suitable for hydrogen storage as a fuel for a longer time and may provide remarkable contributions in diversity of power and transportation applications.