Li原子修饰笼型Si5团簇的结构和储氢性能

摘要

The geometry structures,electronic properties and hydrogen storage properties of Si5 and Li2Si5 clusters are investigated by using the hybrid density functional theory (DFT) B3LYP method at 6-311 + G (d,p) set basis level.Our results indicate that the lowest energy structure of Si5 cluster is a three-dimensional cage,and it can not efficiently store hydrogen molecules for Si5 cage by the same method.It will remarkably improve the hydrogen storage capacity coated by Li atoms.The Si5 cage coated by two Li atoms (Li2Si5) can store up to 10 H2 molecules,in which every Li atom can efficiently adsorb five H2 molecules,corresponding to a maximum mass fraction of 11.554％ with an average adsorption energies of 7.259 ～ 11.330 kJ/mol per H2 molecule.The results demonstrate that Li decorated Si5 cage can serve as an ideal hydrogen storage material under ambient conditions.%采用杂化密度泛函B3LYP理论,对Si5及Li原子修饰的Si5团簇的几何结构和电子性质及储氢性能进行了研究.结果表明:Si5团簇最低能量构型为笼型结构,纯笼型Si5团簇不能有效地吸附氢分子;Li原子的修饰可以显著改善其储氢能力,在两个Li原子端位修饰Si5笼型团簇体系中,其氢分子的平均吸附能为7.259 ～11.330 kJ/mol,每个Li原子周围可以有效吸附5个氢分子,储氢质量分数达11.554％.因此,Li修饰Si5笼型团簇体系有望成为理想的储氢材料.