First-principles Quantum analysis of novel X4Mg3H14 (X= Li and Na) hydrides: Structural, optoelectronic, and hydrogen storage frontiers

초록

Solid-state hydrogen storage is essential for the progression of sustainable energy technologies, and perovskite hydrides have surfaced as viable options. In this study, we utilize density functional theory (DFT) to examine the structural, electrical, optical, and hydrogen storage characteristics of new X4Mg3H14 (X = Li and Na) hydrides. The structural study verifies their thermodynamic and dynamic stability, with Li4Mg3H14 demonstrating superior stability compared to Na4Mg3H14. Electronic band structures and density of states show that both compounds act like metals. Optical studies reveal notable dielectric responses, absorption peaks, and reflectivity, indicating possible optoelectronic uses. The gravimetric hydrogen storage capabilities are 12.29 wt% for Li4Mg3H14 and 7.88 wt% for Na4Mg3H14. These numbers meet and exceed the U.S. DOE goal. The predicted desorption temperatures (335 K for Li4Mg3H14 and 339 K for Na4Mg3H14) show that these materials can be stored at high temperatures. These results show that X4Mg3H14 hydrides, especially Li4Mg3H14, are good candidates for solid-state hydrogen storage applications.

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