Structural phase stability studies on MBeH3 (M = Li, Na, K, Rb, Cs) from density functional calculations
P Vajeeston1, P Ravindran, H Fjellvåg
1Department of Chemistry, Center for Materials Sciences and Nanotechnology, University of Oslo, Box 1033 Blindern, N-0315 Oslo, Norway. ponniahv@kjemi.uio.no
Inorganic Chemistry
|December 20, 2007
Summary
Density functional theory predicts stable MBeH(3) phases for hydrogen storage. These materials exhibit insulating properties and band gaps suitable for various applications.
Area of Science:
- Materials Science
- Computational Chemistry
- Solid State Physics
Background:
- Metal beryllium hydrides (MBeH3) are potential candidates for hydrogen storage materials.
- Understanding their structural and electronic properties is crucial for material design.
Purpose of the Study:
- To predict the ground-state crystal structures and electronic properties of MBeH3 phases using computational methods.
- To evaluate their potential for hydrogen storage.
Main Methods:
- Density functional theory (DFT) calculations were employed.
- Generalized gradient approximation (GGA) was used for electronic structure calculations.
- Structural optimization was performed on 24 initial configurations.
Main Results:
- Ground-state crystal structures were predicted for LiBeH3, NaBeH3, KBeH3, RbBeH3, and CsBeH3.
- LiBeH3 and NaBeH3 adopt perovskite-related orthorhombic and cubic structures, respectively.
- KBeH3, RbBeH3, and CsBeH3 crystallize in a monoclinic structure.
- The predicted MBeH3 phases can store up to 15.93 wt % hydrogen.
- All investigated phases are insulators with band gaps ranging from 1.79 to 3.44 eV.
Conclusions:
- DFT calculations successfully predicted stable MBeH3 phases with potential for hydrogen storage.
- The diverse crystal structures and insulating electronic properties offer avenues for further material development.
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