Li-Al-N-H系络合物贮氢反应的第一性原理研究

Investigations on Li-Al-N-H complex for hydrogen storage by first principle

采用基于密度泛函理论(DFT)的平面波赝势(PW-PP)方法,计算Li-Al-N-H系络合物贮氢反应中各个化合物的晶胞参数、电子结构、生成焓和贮氢反应的反应焓。结果表明:Li3AlN2的Li—N、Al—N键主要为离子键,LiNH2的N—H键主要为共价键,Li—N键主要为离子键;298K时贮氢反应的反应焓计算值分别为-23.7和-55.3kJ/mol,与实验值均符合得较好;反应中各固态、气态物质的晶胞的结构优化后的晶格常数、键长与键角等与相应的实验值均符合较好。

The cell parameters, electronic structures, formation enthalpies and reaction enthalpies of LiNH2 and Li3AlN2 were investigated using plane-wave pseudo-potential method based on density function theory. The results show that the calculated cell parameters are in agreement with the experimental ones. The interactions between Li-N and Al-N are strong ionic bonds in Li3AlN2. The interaction between N and H is strong covalent bond and the interaction between Li and N is strong ionic bond in LiNH2. The calculated reaction enthalpies are -23.7 and -55.3 kJ/mol, respectively, which are in agreement with the experimental ones.