| In this dissertation, by means of plane-wave pseudo-potential method based on the density function theory, the relationship between electronic structures and hydrogen storage properties of ZrMn2 alloy and Li-based metal complex compounds was systemically investigated for developing high quality hydrogen storage materials. The detail contents are the influences of Co substitution for Mn on hydrogen storage properties of ZrMn2 alloy, structures of ZrMn2(110) surface and hydrogen-adsorption mechanism of ZrMn2 alloy, bond characters and hydrogen-storage mechanism of LiAlH4 and Li3AlH6, and thermodynamic stabilities of Li-Al-N-H-based complex compounds. The conclusions are summarized in the followings:1. For ZrMn2 alloys, Co substitution for Mn reduce sizes of some interspaces of ZrMn2-xCox alloys, which is a reason for plateau pressure of alloys increased with Co content. The density of state of Zr 4d band at Fermi level and interactions between H-Zr(2) atoms and H-Mn(6h) atoms act important effects to stability of hydrides.2. Compared with interspaces in ZrMn2 cells, the sizes of interspaces in relaxed ZrMn2(110) surface are small, which is a possible reason that hydrogen atoms are not easy to be pressed into interspaces of unactivated ZrMn2 alloys. The hollow site formed by one Zr and two Mn atoms on the ZrMn2(110) surface is the preferred adsorption position. The maximum potential barrier for hydrogen atoms through ZrMn2(110) surface is 1.033 eV, which indicates that hydrogen atoms are not easy to be pressed unactivated ZrMn2(110) surface.3. For both LiAlH4 and Li3AlH6, the interactions between Al-H atoms and Li-H atoms are strong covalent and ionic bond, respectively. Each step in decomposition reactions of LiAlH4 is endothermic reaction, and the reaction enthalpies of LiAlH4 decomposition reactions increase gradually with LiAlH4 decomposed step by step. The enthalpy change of reaction LiAlH4→LiH +Al+3/2H2 is greater than that ofreaction LiAlH4→1/3Li3AlH6 + 2/3Al + H2 , which indicates that LiAlH4decomposed into Li3AlH6 is easier than that into LiH. It is also a thermodynamic reason that LiAlH4 decomposes into Li3AlH6 and finally into LiH.4. The studies of bond characters and thermodynamic stabilities of Li-Al-N-H-based complex compounds reveal that the interactions between Li-N atoms and Al-N atoms are strong ionic bonds in Li3AlN2, and the interactions between N-H atoms and Li-N atoms are strong covalent bond and ionic bond in LiNH2, respectively. The values of calculated enthalpy change of reaction (1) 2LiNH2+ LiAlH4→Li3AlN2+ 4H2 and (2) LiNH2+2LiH+ AlN(?)Li3AlN2+2H2 at 298K are -23.7 kJ/mol·H2 and -55.3 kJ/mol·H2, which are in good agreement with experimental.
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