I&EC 127 |
| LiAl-substituted MgH2 materials, LiAlMg10H24, was found to be thermodynamically stable and to offer substantially lowered energy barrier and reaction enthalpy for hydrogen storage applications. A quantum mechanical approach, the density functional theory (DFT) method, was used in deriving the stable structure, computing the thermodynamics parameters, and evaluating the hydrogen absorption/desorption reaction kinetics. The composition, LiAlMg10H24, was shown to be capable of retaining the ordered MgH2 crystal structure, with stability verified through the lattice dynamics calculations of the density functional perturbation theory (DFPT) method. The enthalpy of reaction of hydrogen absorption/desorption based on the nano particles built from the crystalline bulk phases was determined to be ca. 61 KJ/molH2, a 14% reduction from that of the pure MgH2 phases. Molecular hydrogen was found to dissociate without an energy barrier at the Li-Al juncture on the surfaces of the nano particles of the LiAlMg10 nominal composition. |
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Computational Material Design in Chemical Industries, Sponsored by Novel Chemistry with Industrial Applications Sub-Division
8:30 AM-11:40 AM, Tuesday, 12 September 2006 Moscone Center -- Room 252/254, Oral
Division of Industrial & Engineering Chemistry |