First-principle study of Li ion diffusion in copper thin film

The diffusion mechanism of Li ion in a copper thin film is investigated from first-principle calculations. The energy barriers for possible spatial hopping pathways are calculated with the adiabatic trajectory method. Theoretically, we have identified that lithium can diffuse through a copper thin film by successive nearest neighbor vacancy-atom exchanges at room temperature. It is found by comparing the different mechanisms that the nearest neighbor vacancy assisted jumping is highly probable. It is also confirmed that more free diffusion may be observed by increasing the number of copper vacancies in the thin film.