Theoretical modeling of hydrogen storage materials: Prediction of structure, chemical bond character, and high-pressure behavior

Vajeeston, Ponniah; Ravindran, P.; Kjekshus, A.; Fjellvåg, Helmer

doi:10.1016/j.jallcom.2005.03.109

Cited by 19 publications

(8 citation statements)

References 34 publications

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“…that the bonds between the cations and the [AlH 4 ] − tetrahedra or the [AlH 6 ] 3 − octahedra are purely ionic, whereas the bonding within the tetrahedron or octahedron is partially ionic and partially covalent ( Fig. 2 ) [28] . It may best be described as covalent with a strong ionicity (polar covalent) [29,30] .…”

Section: Introductionmentioning

confidence: 99%

Crystal structure evolution of complex metal aluminum hydrides upon hydrogen release

Weidenthaler

2020

Journal of Energy Chemistry

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Section: Introductionmentioning

confidence: 99%

Crystal structure evolution of complex metal aluminum hydrides upon hydrogen release

Weidenthaler

2020

Journal of Energy Chemistry

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“…Among all the alkaline-earth hydrides, MgH 2 has been much studied both experimentally − and theoretically − for energy storage applications due to its low manufacturing cost and high gravimetric hydrogen density (7.6 wt %), as well as high volumetric hydrogen density (110 kg/m 3 ). But, the dehydrogenation of MgH 2 requires higher temperature, that is, 552 K (300 °C) at 1 atm. − The high enthalpy of formation (Δ H = −75 kJ/mol) and very slow hydrogenation/dehydrogenation kinetics led MgH 2 as a challenging energy storage material. In order to improve the hydrogen storage property of these hydrides, understanding their stability and analysis of the chemical bonding between the constituents are important.…”

Section: Introductionmentioning

confidence: 99%

Phase Stability, Phase Mixing, and Phase Separation in Fluorinated Alkaline Earth Hydrides

Varunaa¹,

Ravindran

2017

J. Phys. Chem. C

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Alkaline-earth hydrides (AH2) are considered as potential hydrogen storage material. Due to high decomposition temperature and slow sorption kinetics, these hydrides cannot be used for energy storage applications. As fluorine is more electronegative than hydrogen, substitution of hydrogen by fluorine will bring anisotropic bonding interaction, and hence, it may improve the hydrogen storage properties. Hence, the structural stability, electronic structure, and chemical bonding of AH2 and fluorinated AH2 (AH2–x F x ) are delineated using ab initio calculations. From the calculated enthalpy of formation we have predicted that AH2–x F x are relatively more stable than the corresponding pure hydrides. The positive and very low value of enthalpy of mixing for AH2–x F x imply that single-phase of AH2–x F x may form at reasonable temperatures. The band structure and density of states (DOS) calculations reveal that AH2–x F x are insulators. Partial DOS, charge density, electron localization function, and crystal orbital Hamiltonian population analyses conclude that these compounds are governed mainly by ionic bonding. The calculated H site energy increases as the fluorination increases and thus fluorination bring extra stability in the lattice. The present results suggest that hydrogen closer to fluorine can be removed more easily than that far away from fluorine. Hence, the fluorination brings disproportionation in the bonding between the constituents.

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“…Recently, there has been significant interest in the development of condensed-phase hydrogen storage materials. [1][2][3][4][5][6][7][8][9][10] In particular, many studies have focused on lightweight metal hydrides, such as LiH, MgH 2 , LiBH 4 , and LiNH 2 , due to their outstanding properties for practical applications. 11,12 For instance, lithium amide (LiNH 2 ) with a high gravimetric hydrogen density (18.5 wt %) has exhibited safe, efficient, and reversible hydrogen storage capacities, and thus has been studied extensively.…”

Section: Introductionmentioning

confidence: 99%

“…As a lightweight metal hydride (density 1.39 g/cm 3 ), sodium amide crystallizes into an orthorhombic cell under ambient conditions with space group Fddd (D 2h 24 ) and cell parameters a ) 8.964 Å, b ) 10.456 Å, c ) 8.073 Å, and Z ) 16. 17 The unit cell structure of NaNH 2 is shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

In Situ High-Pressure Study of Sodium Amide by Raman and Infrared Spectroscopies

Liu

Song

2010

J. Phys. Chem. B

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Here we report the first in situ high-pressure study of sodium amide (NaNH(2)) as an agent in potential hydrogen storage applications by using combined Raman and infrared (IR) spectroscopies at room temperature and pressures up to ~16 GPa. Starting with an orthorhombic crystal structure at ambient pressure, sodium amide was found to transform to two new phases upon compression as evidenced by the changes in the characteristic Raman and IR modes as well as by examining the pressure dependences of these modes. Raman and IR measurements on NaNH(2) collectively provided consistent information about the structural evolutions of NaNH(2) under compression. Upon decompression, all Raman and IR modes were completely recovered, indicating the reversibility of the pressure-induced transformations in the entire pressure region. The combined Raman and IR spectroscopic data together allowed for the analysis of possible structures of the new high-pressure phases of NaNH(2).

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Theoretical modeling of hydrogen storage materials: Prediction of structure, chemical bond character, and high-pressure behavior

Cited by 19 publications

References 34 publications

Crystal structure evolution of complex metal aluminum hydrides upon hydrogen release

Crystal structure evolution of complex metal aluminum hydrides upon hydrogen release

Phase Stability, Phase Mixing, and Phase Separation in Fluorinated Alkaline Earth Hydrides

In Situ High-Pressure Study of Sodium Amide by Raman and Infrared Spectroscopies

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