First-principles Study of Li Adatom Adsorption and Migration on Perfect/Defected AlN Nanosheets

We present first-principle calculations to understand the adsorption and migration behavior of Li adatoms on perfect as well as defected AlN nanosheets. The defects in 2-D AlN were considered in the form of Al/N vacancy. The migration of Li was considered along four different paths P1, P2, P3 and P4. It is revealed that Adsorption of Li is exothermic in nature and the adsorption energy varies from -0.58 eV to -0.78 eV. Perusal of migration profiles indicates that P3 and P4 are the most favourable paths for Li migration with energy barrier as low as similar to 100 meV whereas the barrier for P1 and P2 is almost doubled. Despite of lower energy barrier, Li migration on perfect AlN nanosheet is expected to be immune at room temperatures whereas the adsorption at vacancy defected surface leads to strong trapping phenomena. Present results suggest that AlN nanosheet could be a potential building block as anode material for energy storage devices.