Studies of the Electronic, Optical, and Thermodynamic Properties for Metal-Doped LiH Crystals by First Principle Calculations

Abstract

Hydrogen as a clean and abundant energy source with high energy density is considered as a promising solution to future energy crisis, although storage of hydrogen is still challenging. Lithium hydride can be an alternative for hydrogen storage because of its small volume and high storage capacities, although this material is unsuitable as hydrogen reservoir because of its high dehydriding temperature. The density functional theory calculations based on the first principle are applied to study the physical properties of LiH without and with different metal M (M=Al, Fe, and Ru). The M-substituted systems exhibit lower dehydriding temperatures than the pure LiH, and Li1−xAlxH may be the most suitable candidate for hydrogen reservoir owing to the high hydrogen content and low dehydriding temperature. The stability and thermodynamic properties for hydrogen storage are discussed for these systems. The kinetics and the optical activity in the visible and infrared regions are enhanced by the metal dopants, characterized by the M impurity bands in the band gaps of the doped systems.