Electronic Structures and Li Migration in Cubic Nickel Nitrides Intercalation compounds : From First Principles Studies

摘要

The electronic structure and diffusion behavior of Li intercalation in cubic Ni4N4 are investigated fromfirst principles calculations. Results indicate that the optimal Li interstitial site is an octahedralinterstitial site in cubic Ni4N4. The Li intercalation energies indicate that the maximum amount oflithium intercalation is seven and the corresponding theoretical specific capacity reaches 644.8 mAh/g,which is far higher than that of commercial graphite (theoretical specific capacity: 372 mAh/g).Moreover, the analyses of the energy bands, density of states, charge density population, and electronlocalization function all indicate that the bonding states are formed by the strong hybridization of theNi 3d and N 2p orbitals. Finally, interstitial Li migration is considered. The results show that interstitialLi migration from octahedral interstitial site (Oh) site to Oh site can be fast with an energy barrier of0.43 eV.