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采用基于密度泛函理论(Density functional theory’DFT)的总体能量和平面波赝势方法,计算了LaNi5-xCox(x=0,0.5)贮氢合金及其氢化物的晶体结构、电子结构和成键特性,获得了其总体能量、能带结构、态密度以及Mulliken布居值;计算结果表明:在LaNi5合金中,Ni2c与La原子间的相互作用大于Ni3g与La原子间的相互作用,Ni2c-Ni2c和Ni3g-Ni3g原子间存在明显的共价作用。合金中引入Co原子和H原子后,Ni2c-Ni2c和Ni3g-Ni3g相互作用明显减弱。H与Ni3g之间共价作用明显大于H与Ni2c间作用,即在四面体中引入H后,晶格膨胀导致Ni2c原子向外移动,使合金a轴膨胀大于c轴膨胀。
The crystal structure, electronic structure and bonding of LaNi5-xCox (x = 0,0.5) hydrogen storage alloys and their hydrides were calculated using the total energy and plane wave pseudopotential method based on Density functional theory (DFT) The results show that in LaNi5 alloy, the interaction between Ni2c and La atoms is larger than the interaction between Ni3g and La atoms, and the Ni2c-Ni2c And Ni3g-Ni3g atoms have obvious covalent interaction. The introduction of Co atoms and H atoms in the alloy significantly reduces the interaction between Ni2c-Ni2c and Ni3g-Ni3g. The covalent interaction between H and Ni3g is obviously larger than that between H and Ni2c. That is to say, the introduction of H into the tetrahedron results in the outward lattice movement of the Ni2c atoms and the expansion of the alloy a-axis more than the c-axis.