Ab-initio investigation of the physical properties of LiBH3 perovskite for hydrogen storage applications

In this paper, a comprehensive ab initio investigation of novel hydride perovskites LibO${}_{3-x}$H${}_x$ (x $=$ 0, 1, 2, 3) was conducted using density functional theory. Their structural, mechanical, thermal, electronic, and optical properties were systematically explored, along with their hydrogen storage capacity and potential as efficient solid-state hydrogen storage materials. Following oxygen-to-hydrogen substitution, LiBH${}_3$ is also examined under 5% and 10% tensile strain to enhance its hydrogen desorption behavior. The complete hydrogenated compound, LiBH${}_3$, exhibits a high gravimetric hydrogen storage capacity of 14.55 wt% and a desorption temperature of 362.10 K, which is higher than that of many conventional hydrides. However, this is achieved at the cost of thermal and mechanical stability. The application of strain effectively lowers the desorption temperature to 343.23 K at 5% strain and 299.93 K at 10% strain, enabling more practical hydrogen release. These findings highlight strain-engineered LiBH${}_3$-based perovskites as tunable, cost-effective materials for hydrogen storage and motivate future experimental validation for clean energy applications.