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

Abstract

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 (C_v) for all LiAH₃ hydrides. It is worth mentioning that the highest C_v 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.