The Influence of the Artificial Nanostructure on the LiF Formation at the Solid-electrolyte Interphase of Carbon-based Anodes

The solid-electrolyte interphase (SEI) is of crucial importance for the performance of Li-ion batteries. Here, Density Functional Theory (DFT) calculations are used to study the formation of one of the simplest and early appearing components of the SEI layer, namely LiF, which is produced by splitting HF impurities. The process is investigated on different models representing the basal and edge planes of a graphitic anode, and on covalently connected carbon nanotubes and graphene sheets, known as pillared graphene. The results show that 2 Li atoms are required to bind F in the ?initial state in order to make the reaction energetically favorable, or alternatively a H atom must be pre-adsorbed. The Li adsorption energy, and thereby the Li coverage at a given potential, varies for the diff?erent carbon structures, demonstrating that the arti?ficial nanostructure of the carbon can in?fluence the formation of the SEI.