NLi_(4)^(+)超碱团簇的结构及储氢性能的理论研究

THEORETICAL STUDY ON THE STRUCTURE AND HYDROGEN STORAGE PROPERITIES OF NLi_(4)^(+) SUPERALKALI CLUSTERS

采用密度泛函理论(B3LYP)方法,在6-311++G(d,p)基组水平上对NLi4超碱团簇和NLi_(4)^(+)超碱离子团簇的几何结构和稳定性等物理化学性质进行理论计算,进而研究NLi_(4)团簇和NLi_(4)^(+)团簇的储氢性能。结果表明:NLi4团簇和NLi4+团簇结构稳定性均比较高,但是通过理论计算表明NLi_(4)团簇不能有效吸附氢分子,而NLi_(4)^(+)团簇在吸附氢分子过程中不仅结构稳定,而且NLi_(4)^(+)团簇中的每一个锂原子均可有效吸附3个氢分子,氢分子平均吸附能为1.517~2.931 kCal/mol,储氢质量分数达36.67 wt%,合适的吸附能和较高储氢容量表明NLi_(4)^(+)团簇可有望成为良好的储氢材料。

Using the density functional theory(B3LYP)method,the geometric structure,stability and other physical and chemical properties of NLi_(4) superalkali clusters and NLi_(4)^(+)superalkali ion clusters were theoretically calculated at the level of 6-311++G(d,p)basis set,and the hydrogen storage properties of NLi_(4) and NLi_(4)^(+)clusters were also studied.The results showed that:both of NLi_(4) and NLi_(4)^(+)clusters had good structural stability,but theoretical calculation showed that NLi_(4) clusters could not effectively adsorb hydrogen molecules,while NLi_(4)^(+)clusters were not only structurally stable in the process of adsorption of hydrogen molecules,but each lithium atom in the NLi_(4)^(+)clusters could effectively adsorb 3 hydrogen molecules.The average adsorption energies of hydrogen molecules was 1.517~2.931 kCal/mol,and the mass fraction of hydrogen storage reached 36.67 wt%.Appropriate adsorption energy and high hydrogen storage density indicated that NLi_(4)^(+)clusters were expected to be good hydrogen storage materials.