A First‐Principles Study of Manganese‐Based Perovskite‐Type Hydrides for Hydrogen Storage Application

Abstract

Herein, a series of perovskite‐type hydride materials RMnH 3 ( R = Ca, Sr, and Ba) are investigated by density functional theory for solid‐state hydrogen storage. Their structural, mechanical, electronic, and optical properties are calculated and their thermodynamic, dynamic, and mechanical stability is assessed. All compounds crystallize in the undistorted cubic perovskite system with the Pm‐3m symmetry. The results from mechanical properties, based on parameters such as Poisson's ratio ( ν ) and the G/B ratio, indicate that CaMnH 3 and SrMnH 3 exhibit brittle behavior, primarily attributed to the dominance of ionic bonds, while BaMnH 3 is distinguished by its ductility, resulting from a prevalence of covalent bonds. Additionally, the electronic structure analysis reveals that all examined hydrides possess metallic behavior. Further calculations of the optical properties are also performed, providing supplementary insights into the physical features of the hydrides. The gravimetric hydrogen storage capacities ( C wt% ) are calculated, with values of 2.96 wt% for CaMnH 3 , 2.019 wt% for SrMnH 3 , and 1.513 wt% for BaMnH 3 , accompanied by respective desorption temperatures of 214.83, 193.42, and 145.43 K. Overall, these results highlight the potential of perovskite hydrides RMnH 3 as promising materials for hydrogen storage applications, significantly contributing to a sustainable energy future.