A Computational Investigation of Lithium-Based Metal Hydrides for Advanced Solid-State Hydrogen Storage

Hydrogen storage is a crucial step in commercializing hydrogen-based energy production. Solid-state hydrogen storage has gained much attention from researchers and needs extensive research. In the present study, we investigate the structural, mechanical, and optoelectronic properties of lithium-based LiAH3 (A=Mn, Fe, Co) metal hydrides to elucidate their potential for solid-state hydrogen storage. First, we evaluate the structure stability of LiAH3 hydrides using formation enthalpies calculations. Then, the mechanical stability is determined by elastic stiffness constants, which reveal that LiAH3 hydrides are stable mechanically as they meet the Born stability requirements. Electronic band structure calculations manifest that all LiAH3 hydrides possess a metallic character. Several optical properties have been discussed in detail. The gravimetric hydrogen storage capacities of LiMnH3, LiFeH3 and LiCoH3 hydrides are 4.65, 4.60 and 4.39 wt%, respectively, achieving the target of US-DOE for rechargeable equipment. Additionally, we have determined the volumetric hydrogen storage capacities (Cv) for all LiAH3 hydrides. It is worth mentioning that the highest Cv values have been obtained to be 180.80, 188.18 and 177.25gH2l-1 for LiMnH3, LiFeH3 and LiCoH3 hydrides, respectively, which have achieved the US-DOE target set for 2025. Our investigation predicts the applicability of lithium-based hydrides as promising solid-state hydrogen storage materials. In this work, we have comprehensively studied the structural, mechanical, optoelectronic and hydrogen storage properties of lithium-based LiAH3 (A=Mn, Fe, Co) metal hydrides. The gravimetric hydrogen storage capacities of LiAH3 hydrides have achieved the target the US-DOE set for rechargeable devices. Furthermore, the volumetric hydrogen storage capacities for the studied hydrides have been obtained to be 180.80, 188.18 and 177.25 gH2l-1 for LiMnH3, LiFeH3 and LiCoH3 hydrides, respectively, which have achieved the US-DOE target set for 2025. Our finding suggests that lithium-based metal hydrides have the potential to be utilized in advanced solid-state hydrogen storage systems. image