Computational analysis of hydrogen storage and physical behavior of Al, Ga, and In-based Copper hydrides

Abstract

Hydrogen is a promising clean energy carrier due to its high gravimetric energy density and decarbonization potential. This study investigates the structural, mechanical, electronic, and hydrogen storage properties of XCuH₃ (X = Al, Ga, In) hydrides using first-principles calculations. The optimized lattice constants are 3.50, 3.56, and 3.69 Å, corresponding to hydrogen storage capacities of 3.23, 2.22, and 1.67 wt% for AlCuH₃, GaCuH₃, and InCuH₃, respectively. AlCuH₃ demonstrates superior mechanical strength, thermal stability, and strong interatomic bonding, supported by its highest Debye temperature, bulk, shear, and Young's moduli. In contrast, InCuH₃ exhibits the greatest ductility with high Pugh's ratio, and pronounced elastic anisotropy, while GaCuH₃ shows intermediate properties. Band structure and density of states confirm metallic behavior, whereas Poisson's ratio highlights the ionic bonding contribution. Overall, these insights enhance the understanding of XCuH₃ hydrides, guiding their potential applications in hydrogen storage and energy technologies.