Enhanced lithium storage and chemical diffusion in metal-LiF nanocomposites: Experimental and theoretical results

An extra storage of Li has been observed experimentally at low potential in Me/LiF nanocomposites where Me refers to transition metals such as Cu, Co, etc., with a pseudocapacitive behavior characterized by a high rate performance. To understand the mechanistic details of the lithium storage anomaly, we have performed comparative ab initio calculations on the atomic and electronic structure of the nonpolar Cu/ LiF001 and model Li/ LiF001 interfaces. For this aim, we inserted extra Li atoms at several possible sites of the periodic two-dimensional Me/LiF Me= Cu, Li interfaces. The energetically most favorable site for extra Li atom is