Ab initio investigations of the electronic structure and chemical bonding of Li2ZrN2

The electronic structure of the ternary nitride Li2ZrN2 is examined from ab initio with DFT computations for an assessment of the properties of chemical bonding. The compound is found insulating with 1.8 eV band gap; it becomes metallic and less ionic upon removal of one equivalent of Li. The chemical interaction is found mainly between Zr and N on one hand and Li and N on the other hand. While all pair interactions are bonding, antibonding N–N interactions are found dominant at the top of the valence band of Li2ZrN2 and they become less intense upon removal of Li. From energy differences the partial delithiation leading to Li2−xZrN2 (x=∼1) is favored.