First-principles calculations to investigate structural, electronic, and thermodynamic properties of ammonia monochloroborane (NH3BH2Cl) as a promising hydrogen storage candidate

This study aims to investigate the structural, electronic, mechanical, piezoelectric, and lattice dynamic proprieties of Ammonia monochloroborane NH3BH2Cl, using first-principles calculations. Both density functional theory and density functional perturbation theory are employed in the computations with generalized gradient approximation and plane waves pseudo-potential formalism. The calculated lattice constants and atomic positions are found in good agreement compared to the experimental values reported in the literature with a deviation of less than 2.85%. The determined density of states reveals that NH3BH2Cl can be considered as an insulator with a wide bandgap of 5.5 eV. Both total and partial density of states, electron local function (ELF), and Born effective charge have been computed to analyse the chemical bond nature of the studied compound. The obtained results indicate the existence of a strong covalent chemical bonding between B and H to form hydric B–H part δ‒, and between N and H to form protic part δ+ in NH3BH2Cl compound. Electronic, dielectric, piezoelectricity and elastic tensors, and vibration modes in Gamma point are calculated and analysed for the first time. The results reveal that NH3BH2Cl is mechanically and dynamically stable. Finally, this study demonstrates that NH3BH2Cl compound can be potentially used as hydrogen storage medium with a capacity of ∼8.5 wt%, besides in piezoelectric (a large value of d15) and wide bandgap devices.