The search for optimum host-guest interactions: Atomic hydrogen storage properties of the novel ternary ordered intermetallic compound Cu3ZnSb: A DFT study

Abstract

Ternary Cu3ZnSb adopts the tetrahedral space group P4/nmm (129), with 10 atoms in the unit cell, distributed over four crystallographic positions in a perfectly ordered manner. It possesses two perfect tetrahedral interstitial positions, namely Cu3Sb and Cu2Zn2. The possible hydrogen storage properties in these two possible sites are explored by the aid of first-principles density functional theory calculations. The Cu-richer Cu3Sb site is energetically more favourable position for hydrogen atom, over the other one. The maximum possible H-uptake capacity would be within the range of ∼4 H per formula unit. The electronic structure modification, host-guest interactions, and electronic redistribution after hydrogen incorporation are explored from fundamental perspectives analyzing the density of states, crystal orbital Hamilton population, crystal orbital bond index, and Mulliken population calculations.