Toward Lightweight Solid-State Hydrogen Storage: Computational Investigation of Potassium Antiperovskites

Abstract

The hydrogen economy presents a promising yet challenging frontier, as hydrogen is an abundant, cost-effective, and non-polluting element, but its application is still grappling with significant hurdles in harnessing its full potential. Using the density-functional theory, the structural, electrical, and mechanical properties of antiperovskite hydrides K3BH (B = S, Se, Te) are investigated. Band structure, total density of states, and partial density of states are determined by examining the electronic properties of the hydrides under consideration. K3BH hydrides exhibit semiconductor characteristics due to their energy bandgap being observed in close proximity to the Fermi level. Using the Perdew–Burke–Ernzerhof–generalized gradient approximation functional, the lattice constants of K3SH, K3SeH, and K3TeH are 5.9177, 6.1316, and 6.5203 Å, respectively. The gravimetric hydrogen-storage capacities are 3.24, 2.49, and 2.008 wt% for K3SH, K3SeH, and K3TeH, accompanied by respective desorption temperatures of 963.88, 793.19, and 672.70 K. These findings indicate that these materials hold significant potential for hydrogen storage. This study represents the first computational exploration of these antiperovskite hydrides, paving the way for transformative advancements in hydrogen-storage technologies.