Li原子修饰笼型Si_5团簇的结构和储氢性能

The structures and hydrogen storage properties of Li atoms decorated Si_5 cluster

采用杂化密度泛函B3LYP理论,对Si_5及Li原子修饰的Si_5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:Si_5团簇最低能量构型为笼型结构,纯笼型Si_5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Si_5笼型团簇体系中,其氢分子的平均吸附能为7.259~11.330 k J/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Si_5笼型团簇体系有望成为理想的储氢材料。

The geometry structures,electronic properties and hydrogen storage properties of Si5and Li2Si5clusters are investigated by using the hybrid density functional theory(DFT)B3LYP method at6311+G(d,p)set basis level.Our results indicate that the lowest energy structure of Si5cluster is a three dimensional cage,and it can not efficiently store hydrogen molecules for Si5cage by the same method.It will remarkably improve the hydrogen storage capacity coated by Li atoms.The Si5cage coated by two Li atoms(Li2Si5)can store up to10H2molecules,in which every Li atom can efficiently adsorb five H2molecules,corresponding to a maximum mass fraction of11554%with an average adsorption energies of7259~11330kJ/mol per H2molecule.The results demonstrate that Li decorated Si5cage can serve as an ideal hydrogen storage material under ambient conditions.