First-principles study of hydrogen storage materials

Computational physics;Hydrogen storage;Condensed matter;Density functional theory

Ma, Zhu ; Physics

University:Georgia Institute of Technology

Department:Physics

关键词: Computational physics;    Hydrogen storage;    Condensed matter;    Density functional theory;   

Others  :  https://smartech.gatech.edu/bitstream/1853/22672/1/ma_zhu_200805_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

In this thesis, we use first-principles calculations to study the structural, electronic, and thermal properties of several complex hydrides. We investigate structural and electronic properties of Na-Li alanates. Although Na alanate can reversibly store H with Ti catalyst, its weight capacity needs to be improved. This can be accomplished by partial replacement of Na with lighter elements. We explore the structures of possible Na-Li alloy alanates, and study their phase stability. We also study the structural and thermal properties of Li/Mg/Li-Mg Amides/Imides. Current experimental results give a disordered model about the structure of Li-Mg Imide, in which the positions of Li and Mg are not specified. In addition the model gives a controversial composition stoichiometry. We try to resolve this controversy by searching for low-energy ordered phases. In the last part, we study the structural, energetic, and electronic properties of the La-Mg-Pd-H system. This quaternary system is another example of hydrogenation-induced metal-nonmetal transition without major reconstruction of metal host structure, and it is also with partial reversible H capacity. Experiment gives partially disordered H occupancy on two Wyckoff positions. Our calculation explains the structural and bonding characteristics observed in experiment.