Thermal stability of the Mg2Ni-based hydrogen storage alloy doped Ti element

Abstract

Crystal structures, electronic structures, thermal stability and dehydrogenation energy of Mg-based hydrogen storage materials were investigated via the first-principle calculations, and the calculations of bonding properties, electronic structure, band structure, density of state, charge density difference and electronic structure of Mg2Ni alloy were examined. Namely, the work mainly took account of doping metal elements Ti to replace Mg and Ni elements in different proportions portion, and then form different crystals, including Mg12Ni6, Mg1.5NiTiMg(2)1/2, Mg5/3NiTiMg(2)1/3, Mg2NiH4, Mg2Ni3/4Ti1/4H4 aimed to improve the hydrogen storage characteristics of Mg-based metal hydrides. The results manifested Ti elements may hold the center position of octahedral sites, and the investigation further indicated that the hydrogen release performance and the thermal stability of hydrogen became lower through calculating absorption reaction enthalpy. Additionally, the metals Ti with high electronegativity interstitially exhibit useful effects on the characteristics of Mg-based hydrogen storage, which is beneficial to find the impact of the mechanism in terms of the electronic structure, and provide the theoretical support for designing new hydrogen storage materials.