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arXiv · 1610.00269

Structural Phase Stability in Fluorinated Calcium Hydride

R. Varunaa·P. Ravindran
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Abstract

In order to improve the hydrogen storage properties of calcium hydride (CaH2), we have tuned its thermodynamical properties through fluorination. Using ab-initio total energy calculations based on density functional theory, the structural stability, electronic structure and chemical bonding of CaH2-xFx systems are investigated. The phase transition of fluorinated systems from orthorhombic to cubic structure has been observed at 18% fluorine doped CaH2. The phase stability analysis shows that CaH2-xFx systems are highly stable and the stability is directly correlating with their ionicity. Density of states (DOS) plot reveals that CaH2-xFx systems are insulators. Partial DOS and charge density analyses conclude that these systems are governed by ionic bonding. Our results show that H closer to F can be removed more easily than that far away from F and this is due to disproportionation induced in the bonding interaction by fluorination.

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R. Varunaa, P. Ravindran. 2016-10-02. Structural Phase Stability in Fluorinated Calcium Hydride. https://doi.org/10.1063/1.4980184

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