Computational exploration of high-capacity hydrogen storage in alkali metal-decorated MgB2 material.

In this study, a novel substrate complex is developed by integrating alkali metals such as Li/Na/K onto magnesium diboride (MgB 2). The research involves comprehensive density functional theory (DFT) to analyze the complex optimized structures, thermodynamic characteristics, and H 2 storage capabilities. The results underscore a subtle charge transfer from Li/Na/K to the pristine MgB 2 monolayer, augmenting its electropositive characteristics. This attribute proves particularly advantageous for H 2 storage, as it enhances the electrostatic interactions between the complex and hydrogen (H 2) molecules. The structure of Li/Na/K-decorated MgB 2 with various numbers of attached H 2 molecules is also explored. The maximum H 2 adsorption is observed with nine H 2 molecules for Li (n = 9H 2) and eight H 2 molecules for both Na and K (n = 8H 2). The adsorption energies for these configurations fall within the range of −0.24 to −0.21 eV for Li, −0.22 to −0.20 eV for Na, and −0.25 to −0.20 eV for K. Notably, gravimetric capacities of 14.6 wt%, 23.37 wt%, and 18.94 wt% are attained for Li, Na, and K-decorated MgB 2 , respectively. These values demonstrate a significant surpassing of the U–S Department of Energy (DOE) target of 5.5 wt%. This groundbreaking material has the potential to play a crucial role in promoting efficient and sustainable solutions for H 2 storage, meeting the increasing need for clean energy technologies. [Display omitted] • DFT study of alkali metal decorated magnesium diboride for hydrogen storage. • Adsorption energies in the range of −0.25 to −0.20 eV Li/Na/K-decorated MgB 2. • H 2 storage capacity of Li/Na/K decorated MgB 2 is 14.60, 23.37, and18.94 wt%. [ABSTRACT FROM AUTHOR]