【摘 要】
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Alloying effect on the stability of MgH2 has been studied by using ab-initio total-energy calculations.Considering two different crystallographic modificati
【机 构】
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School of Materials Science and Engineering,Guilin University of Electronic Technology,Guilin,Guangx
【出 处】
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第十六届全国相图学术会议暨相图与材料设计国际研讨会
论文部分内容阅读
Alloying effect on the stability of MgH2 has been studied by using ab-initio total-energy calculations.Considering two different crystallographic modifications (rutile-type and fluorite-type structures)and the substitution effect from some transitional metals (Sc,Ti,Y),rare earths (La,Ce),and group ⅡA elements (Ca,Sr,Ba),the formation enthalpy and electronic structure of Mg1-xMxH2 have been calculated.The results show that MgH2 with the rutile-type structure becomes unstable and transforms into a fluorite-type structure beyond certain substitutional alloy contents,especially for Ti,Ce and Ba.Further analysis of electronic structure shows that the interactions between the substitutional atoms and H weaken the strength of Mg-H and Mg-Mg bonds,directly lowering the stability of Mg-based hydrides.This work may have predictive value for Mg based hydrogen storage alloy.
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