替代元素对ZrMn2合金及其氢化物电子结构的影晌

采用基于密度泛函的赝势平面波方法,计算Zr4Mn6M2(M=Al,Co,Fe,Mn,V)及其氢化物的电子结构,并分析了成键特性。结果表明,Zr4Mn6M2(M=Al,Co,Fe,Mn,V)中晶胞参数值(a、c值),及其相应氢化物的稳定性都随替代元素M的3d轨道电荷占据数的增加而减小。加Co后Zr4Mn6Co2H12中H分别与Co,Mn的相互作用增强,成键更加稳定,可延长合金的循环寿命,并使平台氢压更趋平坦。加V可使合金氢化物中Mn(2)-H间相互作用减弱,因而加V可以减小吸放氢滞后效应,并有效降低平台氢压。

Influence of Substitute Elements on ZrMn2 Alloy and Electronic Structures of Its Hydrides

Electron structures of Zr4Mn6M2(M=V,Co,Fe,Al,Mn)and their hydrides are calculated by the plane wave pseudo-potential method which is based on density functional theory.It is found that both the lattice parameters of the alloys and their stability decrease with the increase of 3d electrons of the element M. After Co is added, the chemical bonds of the atom H in Zr4Mn6Co2H3 to Mn(2) and Co become stronger and stable. So, Zr4Mn6Co2H 12 has good hydrogen storage, such as longer cycle life and smoother equilibrium plateau pressure. The substitution of the atom V makes the interaction between Mn(2) and H weak and the peak of V 3d band decreased obviously in the electron density of states. As a result,the equilibrium plateau pressure and hysteresis of Zr4Mn6V2H 12 is less than that of ZrMn2H3.