吸热型金属合金化对钒基贮氢材料性能的影响

Theoretical Study of the Effect of Endothermic Alloying on Storage Hydrogen Materials

利用电荷自洽离散变分Xα(SCC-DV-Xα)方法计算了吸热型金属合金化对钒基贮氢材料性能的影响。研究表明:在V63H64中加入吸热型金属Cr、Mn、Ni后,随着原子序数的增加,V51M12H64中H的净电荷依次逐渐增加,V的净电荷逐渐减小;氢化物V51M12H64中V-H之间的离子性相互作用逐渐减弱,共价性相互作用逐渐增强;V-H之间的相互作用主要是V-4s和H-1s、H-2s轨道之间的相互作用。研究还表明材料放氢的平衡压力与其费米能有很好的线性关系,加入吸热型金属后,导致氢化物V51M12H64中费米能增加,氢化物更不稳定,从而改善材料的吸放氢性能。

The effect of endothermic alloying on Vanadium-based hydrogen storage materials is calculated by using the Xα（SCC-DV-Xα）cluster method. The results shows that： when endothermic alloys, Cr, Mn, Ni are added into V63H64. the net charge of H in V51M12H64 increases gradually while that of V decreases by inches with the increment of atomic number. Moreover, the ionic interaction between V and H in V51M12H64 decreases while the covalent interaction strengthens gradually. And the orbital interaction between V and H is mainly among the 4s of V, ls and 2s of H. It also indicates from the calculation that the equilibrium plateau pressure of releasing hydrogen of material is directly proportional to the Fermi energy. And the Fermi energy of V51M12H64 increases thus the hydride becomes more unstable, so the hydrogen storage properties are improved effectively, from introduction of endothermic alloy into these Vanadium-based hydrogen storage materials.